Patent Publication Number: US-2021195669-A1

Title: Wireless in-vehicle networking architecture

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of and priority to U.S. Provisional Patent Application No. 62/952,554, filed Dec. 23, 2019, which is assigned to the assignee hereof and herein incorporated by reference in its entirety as if fully set forth below and for all applicable purposes. 
    
    
     BACKGROUND 
     Field of the Disclosure 
     Aspects of the present disclosure relate to wireless communications, and more particularly, to techniques for wirelessly networking devices in vehicles and improving communications reliability for wireless in-vehicle networks. 
     Description of Related Art 
     Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, broadcasts, etc. These wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power, etc.). Examples of such multiple-access systems include 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) systems, LTE Advanced (LTE-A) systems, code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems, to name a few. 
     These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level. New radio (e.g., 5G NR) is an example of an emerging telecommunication standard. NR is a set of enhancements to the LTE mobile standard promulgated by 3GPP. NR is designed to better support mobile broadband Internet access by improving spectral efficiency, lowering costs, improving services, making use of new spectrum, and better integrating with other open standards using OFDMA with a cyclic prefix (CP) on the downlink (DL) and on the uplink (UL). To these ends, NR supports beamforming, multiple-input multiple-output (MIMO) antenna technology, and carrier aggregation. 
     However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in NR and LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies. 
     SUMMARY 
     The systems, methods, and devices of the disclosure each have several aspects, no single one of which is solely responsible for its desirable attributes. Without limiting the scope of this disclosure as expressed by the claims that follow, some features will now be discussed briefly. After considering this discussion, and particularly after reading the section entitled “Detailed Description” one will understand how the features of this disclosure provide advantages that include reduced component costs, reduced weight, improved design flexibility, improved manufacturing flexibility, redundancy for critical networks, and higher communications reliability for in-vehicle networks. 
     Certain aspects provide a method for wireless communication performed by a device in a vehicle. The method generally includes wirelessly transmitting a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle; wirelessly transmitting the data packet to a transmission relay, wherein the intended destination of the data packet is the other device; monitoring for an acknowledgment (ACK) of the data packet from at least one of the other device or the transmission relay; and deciding whether to retransmit the data packet to at least one of the other device or the transmission relay. 
     Certain aspects provide a method for wireless communication performed by a central controller in a vehicle. The method generally includes receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and wirelessly transmitting, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to another device and second transmission resources for a second transmission to a first transmission relay. 
     Certain aspects provide a method for wireless communication performed by a device in a vehicle. The method generally includes receiving one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receiving a data packet from another device other than the central controller via the transmission resources; and wirelessly receiving the data packet from a first transmission relay via the transmission resources. 
     Certain aspects provide a method for wireless communication performed by a transmission relay in a vehicle. The method generally includes receiving one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receiving a data packet from a first device via a first device-to-device (D2D) communication link on the transmission resources; and wirelessly transmitting the data packet to a second device via a second D2D communication link on the transmission resources. 
     Aspects of the present disclosure provide means for, apparatus, processors, and computer-readable mediums for performing the methods described herein. 
     To the accomplishment of the foregoing and related ends, the one or more aspects comprise the features hereinafter fully described and particularly pointed out in the claims. The following description and the appended drawings set forth in detail certain illustrative features of the one or more aspects. These features are indicative, however, of but a few of the various ways in which the principles of various aspects may be employed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above-recited features of the present disclosure can be understood in detail, a more particular description, briefly summarized above, may be had by reference to aspects, some of which are illustrated in the drawings. It is to be noted, however, that the appended drawings illustrate only certain typical aspects of this disclosure and are therefore not to be considered limiting of its scope, for the description may admit to other equally effective aspects. 
         FIG. 1  is a block diagram conceptually illustrating an example telecommunications system, in accordance with certain aspects of the present disclosure. 
         FIG. 2  is a block diagram conceptually illustrating a design of an example a base station (BS) and user equipment (UE), in accordance with certain aspects of the present disclosure. 
         FIG. 3  shows an exemplary vehicle, according to previously known techniques. 
         FIG. 4  shows an exemplary vehicle, according to aspects of the present disclosure. 
         FIG. 5A  is a schematic diagram of an exemplary wIVN illustrating a transmission procedure, according to aspects of the present disclosure. 
         FIG. 5B  is a schematic diagram of an exemplary wIVN illustrating an interference management procedure, according to aspects of the present disclosure. 
         FIG. 6  is a flow diagram illustrating example operations for wireless communication by a transmitting device in a vehicle, in accordance with certain aspects of the present disclosure. 
         FIG. 7  is a flow diagram illustrating example operations for wireless communication by a central controller in a vehicle, in accordance with certain aspects of the present disclosure. 
         FIG. 8  is a flow diagram illustrating example operations for wireless communication by a receiving device in a vehicle, in accordance with certain aspects of the present disclosure. 
         FIG. 9  is a flow diagram illustrating example operations for wireless communication by a relay in a vehicle, in accordance with certain aspects of the present disclosure. 
         FIG. 10  is a call flow diagram illustrating example signaling for wireless in-vehicle networks, in accordance with aspects of the present disclosure. 
         FIG. 11  illustrates a communications device that may include various components configured to perform the operations shown in  FIG. 6 , in accordance with aspects of the present disclosure. 
         FIG. 12  illustrates a communications device that may include various components configured to perform the operations shown in  FIG. 7 , in accordance with aspects of the present disclosure. 
         FIG. 13  illustrates a communications device that may include various components configured to perform the operations shown in  FIG. 8 , in accordance with aspects of the present disclosure. 
         FIG. 14  illustrates a communications device that may include various components configured to perform the operations shown in  FIG. 9 , in accordance with aspects of the present disclosure. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one aspect may be beneficially utilized on other aspects without specific recitation. 
     DETAILED DESCRIPTION 
     Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for wirelessly networking devices in vehicles and improving communications reliability for wireless in-vehicle networks. According to previously known techniques, vehicles use wired in-vehicle networks (IVN). With the development of autonomous driving, more devices and sensors are connected in vehicles currently being produced or developed. The increased numbers of devices and sensors leads to significant increases in numbers of connections in a vehicle, which leads to complications in wiring in the vehicles. The increase in number of connections and complicated wiring pose significant problems for vehicle manufacturers, due to the weight, cost, design complexity, installation complexity, and maintenance complexity caused by the increased numbers of devices and sensors. It is therefore desirable to develop wireless IVN. However, to support IVN applications, it is desirable that wireless connections support extremely high reliability (e.g., 10 −7  or better reliability) with retransmissions in the network. It is also desirable that wireless IVN support relatively low latency (e.g., 10-30 ms latency) to meet service criteria of the IVN applications. It is desirable that wireless IVN meet these reliability and latency criteria in the presence of interference between the devices and interference from other vehicles or radio sources in proximity to a vehicle. 
     According to aspects of the present disclosure, techniques for employing a centrally controlled direct communication model with additional relays in a wireless in-vehicle network (wIVN) to achieve high reliability are provided. 
     In aspects of the present disclosure, a central controller manages resource allocation, timing, synchronization, and interference mitigation from other vehicles based on device reporting in a wireless in-vehicle network. 
     According to aspects of the present disclosure, usage of a transmission relay may provide higher reliability support in a managed manner in a wireless in-vehicle network. 
     The following description provides examples of wireless in-vehicle networks, and is not limiting of the scope, applicability, or examples set forth in the claims. Changes may be made in the function and arrangement of elements discussed without departing from the scope of the disclosure. Various examples may omit, substitute, or add various procedures or components as appropriate. For instance, the methods described may be performed in an order different from that described, and various steps may be added, omitted, or combined. Also, features described with respect to some examples may be combined in some other examples. For example, an apparatus may be implemented or a method may be practiced using any number of the aspects set forth herein. In addition, the scope of the disclosure is intended to cover such an apparatus or method which is practiced using other structure, functionality, or structure and functionality in addition to, or other than, the various aspects of the disclosure set forth herein. It should be understood that any aspect of the disclosure disclosed herein may be embodied by one or more elements of a claim. The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any aspect described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other aspects. 
     In general, any number of wireless networks may be deployed in a given geographic area. Each wireless network may support a particular radio access technology (RAT) and may operate on one or more frequencies. A RAT may also be referred to as a radio technology, an air interface, etc. A frequency may also be referred to as a carrier, a subcarrier, a frequency channel, a tone, a subband, etc. Each frequency may support a single RAT in a given geographic area in order to avoid interference between wireless networks of different RATs. In some cases, a 5G NR RAT network may be deployed. 
       FIG. 1  illustrates an example wireless communication network  100  in which aspects of the present disclosure may be performed. For example, the wireless communication network  100  may be an NR system (e.g., a 5G NR network). 
     As illustrated in  FIG. 1 , the wireless communication network  100  may include a number of base stations (BSs)  110   a - z  (each also individually referred to herein as BS  110  or collectively as BSs  110 ) and other network entities. A BS  110  may provide communication coverage for a particular geographic area, sometimes referred to as a “cell”, which may be stationary or may move according to the location of a mobile BS  110 . In some examples, the BSs  110  may be interconnected to one another and/or to one or more other BSs or network nodes (not shown) in wireless communication network  100  through various types of backhaul interfaces (e.g., a direct physical connection, a wireless connection, a virtual network, or the like) using any suitable transport network. In the example shown in  FIG. 1 , the BSs  110   a,    110   b  and  110   c  may be macro BSs for the macro cells  102   a,    102   b  and  102   c,  respectively. The BS  110   x  may be a pico BS for a pico cell  102   x.  The BSs  110   y  and  110   z  may be femto BSs for the femto cells  102   y  and  102   z , respectively. A BS may support one or multiple cells. The BSs  110  communicate with user equipment (UEs)  120   a - y  (each also individually referred to herein as UE  120  or collectively as UEs  120 ) in the wireless communication network  100 . The UEs  120  (e.g.,  120   x,    120   y,  etc.) may be dispersed throughout the wireless communication network  100 , and each UE  120  may be stationary or mobile. 
     According to certain aspects, the BSs  110  and UEs  120  may be configured for wireless in-vehicle networking. For example, BS  110   a  may be installed in a vehicle as a central controller of a wireless in-vehicle network, and UE  120   a  may be a device (e.g., a sensor, a camera, an engine controller, or a display) installed in the vehicle and wirelessly networked to the central controller and other devices in the vehicle. As shown in  FIG. 1 , the BS  110   a  includes a wireless in-vehicle networking manager  112 . The wireless in-vehicle networking manager  112  may be configured to receive, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and to wirelessly transmit, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to another device and second transmission resources for a second transmission to a first transmission relay, in accordance with aspects of the present disclosure. In some examples, the wireless in-vehicle networking manager  112  may receive one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receive a data packet from a first device other than the central controller via the transmission resources; and wirelessly transmit the data packet to a second device via the transmission resources. As shown in  FIG. 1 , the UE  120   a  includes a wireless in-vehicle networking manager  122 . The wireless in-vehicle networking manager  122  may be configured to wirelessly transmit a data packet directly to another device in the vehicle; to wirelessly transmit the data packet to a transmission relay, wherein the intended destination of the data packet is the other device; to monitor for an acknowledgment (ACK) of the data packet from at least one of the other device or the transmission relay; and to decide whether to retransmit the data packet to at least one of the other device or the transmission relay, in accordance with aspects of the present disclosure. In some examples, the wireless in-vehicle networking manager  122  may receive one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receive a data packet from another device other than the central controller via the transmission resources; and wirelessly receive the data packet from a first transmission relay via the transmission resources. 
     Wireless communication network  100  may also include relay stations (e.g., relay station  110   r ), also referred to as relays or the like, that receive a transmission of data and/or other information from an upstream station (e.g., a BS  110   a  or a UE  120   r ) and sends a transmission of the data and/or other information to a downstream station (e.g., a UE  120  or a BS  110 ), or that relays transmissions between UEs  120 , to facilitate communication between devices. The relays may be configured to receive one or more allocations of transmission resources from a central controller in the vehicle; to wirelessly receive a data packet from a first device other than the central controller via the transmission resources; and to wirelessly transmit the data packet to a second device via the transmission resources. 
       FIG. 2  illustrates example components of BS  110   a  and UE  120   a  (e.g., in the wireless communication network  100  of  FIG. 1 ), which may be used to implement aspects of the present disclosure. 
     At the BS  110   a,  a transmit processor  220  may receive data from a data source  212  and control information from a controller/processor  240 . The control information may be for the physical broadcast channel (PBCH), physical control format indicator channel (PCFICH), physical hybrid ARQ indicator channel (PHICH), physical downlink control channel (PDCCH), group common PDCCH (GC PDCCH), etc. The data may be for the physical downlink shared channel (PDSCH), etc. The processor  220  may process (e.g., encode and symbol map) the data and control information to obtain data symbols and control symbols, respectively. The transmit processor  220  may also generate reference symbols, such as for the primary synchronization signal (PSS), secondary synchronization signal (SSS), and cell-specific reference signal (CRS). A transmit (TX) multiple-input multiple-output (MIMO) processor  230  may perform spatial processing (e.g., precoding) on the data symbols, the control symbols, and/or the reference symbols, if applicable, and may provide output symbol streams to the modulators (MODs)  232   a - 232   t.  Each modulator  232  may process a respective output symbol stream (e.g., for OFDM, etc.) to obtain an output sample stream. Each modulator may further process (e.g., convert to analog, amplify, filter, and upconvert) the output sample stream to obtain a downlink signal. Downlink signals from modulators  232   a - 232   t  may be transmitted via the antennas  234   a - 234   t,  respectively. 
     At the UE  120   a,  the antennas  252   a - 252   r  may receive the downlink signals from the BS  110   a  and may provide received signals to the demodulators (DEMODs) in transceivers  254   a - 254   r,  respectively. Each demodulator  254  may condition (e.g., filter, amplify, downconvert, and digitize) a respective received signal to obtain input samples. Each demodulator may further process the input samples (e.g., for OFDM, etc.) to obtain received symbols. A MIMO detector  256  may obtain received symbols from all the demodulators  254   a - 254   r,  perform MIMO detection on the received symbols if applicable, and provide detected symbols. A receive processor  258  may process (e.g., demodulate, deinterleave, and decode) the detected symbols, provide decoded data for the UE  120   a  to a data sink  260 , and provide decoded control information to a controller/processor  280 . 
     On the uplink, at UE  120   a,  a transmit processor  264  may receive and process data (e.g., for the physical uplink shared channel (PUSCH)) from a data source  262  and control information (e.g., for the physical uplink control channel (PUCCH) from the controller/processor  280 . The transmit processor  264  may also generate reference symbols for a reference signal (e.g., for the sounding reference signal (SRS)). The symbols from the transmit processor  264  may be precoded by a TX MIMO processor  266  if applicable, further processed by the demodulators in transceivers  254   a - 254   r  (e.g., for SC-FDM, etc.), and transmitted to the BS  110   a.  At the BS  110   a,  the uplink signals from the UE  120   a  may be received by the antennas  234 , processed by the modulators  232 , detected by a MIMO detector  236  if applicable, and further processed by a receive processor  238  to obtain decoded data and control information sent by the UE  120   a.  The receive processor  238  may provide the decoded data to a data sink  239  and the decoded control information to the controller/processor  240 . 
     The memories  242  and  282  may store data and program codes for BS  110   a  and UE  120   a,  respectively. A scheduler  244  may schedule UEs for data transmission on the downlink and/or uplink. 
     The controller/processor  280  and/or other processors and modules at the UE  120   a  may perform or direct the execution of processes for the techniques described herein. For example, as shown in  FIG. 2 , the controller/processor  240  of the BS  110   a  has a wireless in-vehicle networking manager  241  that may be configured for receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and for wirelessly transmitting, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to another device and second transmission resources for a second transmission to a first transmission relay, according to aspects described herein. As shown in  FIG. 2 , the controller/processor  280  of the UE  120   a  has a wireless in-vehicle networking manager  281  that may be configured for wirelessly transmitting a data packet directly to another device in the vehicle; for wirelessly transmitting the data packet to a transmission relay, wherein the intended destination of the data packet is the other device; for monitoring for an acknowledgment (ACK) of the data packet from at least one of the other device or the transmission relay; and for deciding whether to retransmit the data packet to at least one of the other device or the transmission relay, according to aspects described herein. Although shown at the Controller/Processor, other components of the UE  120   a  and BS  110   a  may be used performing the operations described herein. 
       FIG. 3  shows an exemplary vehicle  300 , according to previously known techniques. The exemplary vehicle includes door sensors  305   a - b , cameras  310   a - d , in-cabin sensors  315   a - d , engine sensors  320   a - b , an exhaust sensor  325 , and a display  330 , which may be collectively referred to as devices. According to previously known techniques, the various devices may communicate with each other via a wired in-vehicle network via a bus that may be an implementation of a controller area network (CAN) bus, an Ethernet bus, or some other type of bus. 
     As discussed above, increasing numbers of devices and sensors in vehicles being developed leads to significant increases in numbers of connections in a vehicle, which leads to complications in wiring in the vehicles. The increase in number of connections and complicated wiring pose significant problems for vehicle manufacturers, due to the weight, cost, design complexity, installation complexity, and maintenance complexity caused by the increased numbers of devices and sensors. 
     Accordingly, it is desirable to develop techniques and apparatus for wireless IVN. 
     Example Wireless In-Vehicle Networking Architecture 
     Aspects of the present disclosure provide apparatus, methods, processing systems, and computer readable mediums for wirelessly networking devices in vehicles and improving communications reliability for wireless in-vehicle networks. 
       FIG. 4  shows an exemplary vehicle  400 , according to aspects of the present disclosure. The exemplary vehicle is similar to the exemplary vehicle  300  includes door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , an exhaust sensor  425 , and a display  430 , which may be collectively referred to as devices. According to aspects of the present disclosure, the exemplary vehicle also has a wireless network controller  450  and a wireless relay  460 . In the exemplary vehicle  400 , the various devices may with each other via a wireless in-vehicle network controlled by the wireless in-vehicle network controller  450  (wIVN controller). As illustrated, a device such as camera  410   b  may send a data packet directly to another device, such as display  430 , without the data packet going through the wIVN controller  450 . Also as illustrated a device such as camera  410   b  may send the data packet to another device, such as display  430 , via the relay  460 . 
     According to aspects of the present disclosure, a wireless in-vehicle network may operate according to 5G NR standards. 
     In aspects of the present disclosure, the controller  430  may serve as a relay in addition to acting as a network controller, if needed. That is, a device, such as camera  410   c,  may send a data packet to another device, such as display  430 , via the wIVN controller  450 . The wIVN controller receives the data packet, which includes an indication of an address of the destination device, and the controller forwards the data packet to the destination device. The wIVN controller  450  may determine the radio resources for the Relay  460 , or itself, for the forwarding of the packet from the source device  410   c,  as part of the resource allocation procedure. If the radio resources for the source device  410 &#39;s transmission and the forwarding is allocated and made known to the Relay  460  or the wIVN controller  450 , they may receive the transmission from source device  410   c  according to the resources allocation and forward the packet according to the forwarding resources allocation. 
     According to aspects of the present disclosure, a vehicle may have more than one relay, depending on the vehicle&#39;s design. The wIVN controller may also instruct different wireless in vehicle devices to act as Relays in the process of registration and authorization. 
     In aspects of the present disclosure, a wIVN controller may manage resource (e.g., time resources, frequency resources, and code resources) allocations for the various wIVN devices in a vehicle. 
     According to aspects of the present disclosure, wIVN devices may register with a wIVN controller using pre-configured security certificates in a manner similar to a vehicle-to-anything (V2X) unicast security model). 
     In aspects of the present disclosure, a wIVN controller may provide timing synchronization to all wIVN devices. 
     According to aspects of the present disclosure, transmissions between different wIVN devices are controlled by a wIVN controller. That is, a device, such as camera  410   a,  may transmit to another device, such as display  430 , using transmission resources granted for the transmission by the wIVN controller. 
     In aspects of the present disclosure, a wIVN controller may be considered a special wIVN device that may, for example, have a special pre-determined address. Alternatively or additionally, a wIVN controller may have an address that is learned by other wIVN devices when the other wIVN devices register with the wIVN controller. In some aspects of the present disclosure, a wIVN controller may broadcast (e.g., via a device-to-device (D2D) link) an announcement advertising the address of the wIVN controller, and other wIVN devices may obtain the address of the wIVN controller from the announcement. 
     Alternatively, a wIVN controller can act as a base station. That is, wIVN devices may use a Uu interface for UL and DL communications with the wIVN controller. The wIVN controller may then transmit resource allocations via the Uu interface to a transmitting device and a destination (i.e., receiving) device. In this case, the security association establishment may make use of non-access stratum (NAS) protocol (i.e., the wIVN controller has a mini 5G controller). In addition, when the wIVN controller acts as the base station, it may allocate the radio resources for direct wIVN devices communications over the Uu interface. The wIVN devices uses the allocated radio resources to perform communication directly over the device-to-device communication link. 
     According to aspects of the present disclosure, an address of a wIVN device in the wireless in-vehicle network may be mapped from wired IVN bus addresses. For example for devices on a controller area network (CAN) bus in a vehicle, the addresses of the devices may be mapped by the wIVN controller at registration time. The wIVN controller may, for example, allocate a prefix for devices on the CAN Bus. 
     In aspects of the present disclosure, different IVN buses (e.g., a CAN bus, a media oriented systems transport (MOST) bus, or an Ethernet bus) may be designated by the wIVN controller to different wireless channels (e.g., different frequency bands or different carrier frequencies within a frequency band). 
     According to aspects of the present disclosure, different buses of the same type (e.g., power train CAN or chassis CAN) may be designated by the wIVN controller to different wireless channels. 
       FIG. 5A  is a schematic diagram of an exemplary wIVN  500  illustrating a procedure for requesting a resources for transmission in wIVN networks, according to aspects of the present disclosure. In the exemplary wIVN  500 , a device (e.g., a camera)  510  determines to transmit data to another device (e.g., a display)  520 . The device  510  sends a transmit request  530  to a wIVN controller  515 . The transmit request may include an identifier of the device  510  and an identifier of the device  520 . The wIVN controller sends a transmit grant  532  to the device  510 . The transmit grant may include indications of transmission resources (e.g., time resources, frequency resources, or code resources). 
     The wIVN controller may optionally send a receive grant  534  to the device  520 . The receive grant can be for multiple devices, and may serve as a wake up signal for receiving devices (e.g., when a receiving device may power off in order to save power). The receive grant may indicate an identifier of the device  510  and the transmission resources on which the device  520  should receive the transmission from device  510 . The device  510  then transmits the data  536  to the device  520  via the transmission resources granted by the wIVN controller in the transmit grant  530 . 
     According to aspects of the present disclosure, a wIVN may use an enhanced Uu link for an NR sidelink Mode 1 operation for communications between devices. 
     In aspects of the present disclosure, a wIVN may use an enhanced PC5 sidelink design for communications between devices and allocating resources and managing interference. 
       FIG. 5B  is a schematic diagram of an exemplary wIVN  550  illustrating a procedure for a wIVN controller to configure reporting for interference management, according to aspects of the present disclosure. In the exemplary wIVN  550 , a wIVN controller  560  may configure a device  570  for interference management (e.g., by setting interference measurement thresholds and channels on which to measure interference) by sending an interference measurement configuration message  580  to the device. The device measures interference  590  and transmits a measurement report  582  to the wIVN controller, e.g. when the threshold is crossed. The wIVN controller may then adjust the operational configuration of the controller  560  and/or other devices, including device  570 , based on the measured interference. For example, the wIVN controller may send an interference measurement reconfiguration message  584  to the device. The wIVN controller may also optionally obtain interference assistance from a wide-area network (e.g., a public land mobile network (PLMN)) or from other vehicles using, e.g., inter-controller coordination. The wIVN controllers of different vehicles may be able to communicate with each other via Sidelink, which is already available for V2X communications. 
     According to aspects of the present disclosure, ultra-high reliability in wIVN may be accomplished with relays. Reliability superior to previously known wireless networking techniques may be achieved by utilizing wIVN with relay devices to act as redundant paths for messages. 
     In aspects of the present disclosure, wIVN devices can be configured by the controller to transmit data as groupcast messages to both the intended receiver and to one or more relays in the vehicle. 
     Alternatively, wIVN devices can be configured by the controller to transmit data as individual messages to each of the intended receiver and one or more relays in the vehicle. 
     According to aspects of the present disclosure, a controller can indicate in a receive grant (i.e., a grant indicating a recipient should receive a transmission) to a relay an intended destination for the packet the relay receives in response to the receive grant (i.e., the device that the transmitting device intends to receive the packet). 
     In aspects of the present disclosure, more than one relay may be deployed in a vehicle, depending on the vehicle and the network architecture. In some aspects, all wIVN devices may have the capability to act as a Relay, and upon registration with the wIVN controller, they may be instructed to operate as Relays for some transmissions or some group of UEs. 
     According to aspects of the present disclosure, the improved reliability enabled by use of a relay may be shown by comparing a hypothetical error probability (P(error)) of 10 −3  for a wireless transmission network which uses no relays with the hypothetical error probability of a wIVN using a single relay and the same 10 −3  error probability on each transmission. The hypothetical error probability of a wIVN using a single relay may be calculated as shown below: 
         P (error)= P (error in original transmission)× P (error in relay transmission)
 
         P (error)=10 −3 ×[1−(1−10 −3 ) 2 ]
 
         P (error)=10 −3 ×[1−(1−2×10 −3 +10 −6 )]
 
         P (error)=10 −3 ×[2×10 −3 −10 −6 ]
 
         P (error)=2×10 −6 −10 −9  
 
       FIG. 6  is a flow diagram illustrating example operations  600  for wireless communication, in accordance with certain aspects of the present disclosure. The operations  600  may be performed, for example, by a device in a vehicle (e.g., such as the UE  120   a  in the wireless communication network  100  or the device  410   b  in the vehicle  400 ). Operations  600  may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor  280  of  FIG. 2 ). Further, the transmission and reception of signals by the device in operations  600  may be enabled, for example, by one or more antennas (e.g., antennas  252  of  FIG. 2 ). In certain aspects, the transmission and/or reception of signals by the device may be implemented via a bus interface of one or more processors (e.g., controller/processor  280 ) obtaining and/or outputting signals. 
     The operations  600  may begin, at block  605 , by the device wirelessly transmitting a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle. For example and with reference to  FIG. 4 , the device may be one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , and the exhaust sensor  425  transmitting a data packet directly via a D2D communication link to the display  430 , without going through the wIVN controller  450 . As an example, the camera  410   a  may rely on a sidelink channel, which is an example of a D2D communication link, to send a data packet conveying captured image data to the display  430 . 
     Operations  600  continue at block  610  with the device monitoring for an acknowledgment (ACK) of the data packet. Continuing the example from above, the camera  410   a  monitors for an ACK of the data packet sent to the display  430 . 
     At block  615 , operations  600  continue with the device deciding whether to retransmit the data packet to the other device, based on the monitoring. Continuing the example from above, if the camera  410   a  fails to receive an ACK while monitoring in block  610 , the camera  410   a  may decide to retransmit the data packet to the display  430 . If the camera  410   a  does receive an ACK while monitoring in block  610 , then the camera  410   a  may decide not to retransmit the data packet to the display  430 . 
     In aspects of the present disclosure, a device performing operations  600  may wirelessly transmit the data packet to a transmission relay, wherein the intended destination of the data packet is the other device and wherein the monitoring for the ACK comprises monitoring for a first ACK from the other device and a second ACK from the transmission relay. According to aspects of the present disclosure, the device performing operations  600  (such as one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , the exhaust sensor  425 , and the display  430 ) may receive an allocation of first transmission resources from a central controller in the vehicle, wherein wirelessly transmitting the data packet directly to the other device comprises transmitting the data packet via the first transmission resources; and receive an allocation of second transmission resources from the central controller, wherein wirelessly transmitting the data packet to the transmission relay comprises transmitting the data packet via the second transmission resources. The device may also transmit a request for the allocation of first transmission resources and the allocation of second transmission resources to the central controller. The device may also register with the central controller prior to receiving the allocation of the first transmission resources. In aspects of the present disclosure, receiving the allocation of the first transmission resources may include receiving the allocation of the first transmission resources via a second D2D communication link (e.g., an enhanced PC5 sidelink or a Uu sidelink) and receiving the allocation of the second transmission resources may include receiving the allocation of the second transmission resources via the second D2D communication link or a third D2D communication link. According to aspects of the present disclosure, the device may discover an address of the central controller based on a broadcast via a device-to-device (D2D) communication link (e.g., one of the first, the second, the third, or a fourth D2D communication links). In aspects of the present disclosure, wirelessly transmitting the data packet to the transmission relay may include wirelessly transmitting the data packet to the central controller. That is, the central controller may act as the relay. 
     In aspects of the present disclosure, a device performing operations  600  may receive an allocation of first transmission resources from a central controller in the vehicle, wherein wirelessly transmitting the data packet directly to the other device as in block  605  may include transmitting the data packet via the first transmission resources. The device may discover an address of the central controller based on a broadcast via a device-to-device (D2D) communication link (e.g., the first or a second D2D communication link). According to some aspects of the present disclosure, receiving the allocation of the first transmission resources may include receiving the allocation of the first transmission resources via the first or a second D2D communication link (e.g., an enhanced PC5 sidelink or a Uu sidelink). 
     According to aspects of the present disclosure, the device performing operations  600  may wirelessly transmit the data packet to a second transmission relay, wherein the intended destination of the data packet is the other device. 
     In aspects of the present disclosure, a device performing operations  600  may determine a wireless in-vehicle-network address of the device (i.e., the device&#39;s own address) based on a wired in-vehicle-network bus to which the device is connected. 
     According to aspects of the present disclosure, wirelessly transmitting the data packet directly via the first D2D communication link to the other device as in block  605  may include transmitting simultaneously with a transmission relay transmitting the data packet to the other device. 
     In aspects of the present disclosure, a device performing operations  600  may receive, over the first or a second D2D communication link, a configuration (e.g., a configuration file indicating which frequencies to measure when and/or a command to measure one or more frequencies at one or more times) for the measurement of interference; and report an interference measurement according to the configuration. The device may also receive a configuration update for the wirelessly transmitting the data packet (e.g., indicating a precoder to use), wherein the configuration update is determined based on the interference measurement. 
       FIG. 7  is a flow diagram illustrating example operations  700  for wireless communication, in accordance with certain aspects of the present disclosure. The operations  700  may be performed, for example, by a central controller similar to a BS (e.g., such as a BS  110   a  in the wireless communication network  100  or the central controller  450  in the vehicle  400 ). Operations  700  may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor  240  of  FIG. 2 ). Further, the transmission and reception of signals by the central controller in operations  700  may be enabled, for example, by one or more antennas (e.g., antennas  234  of  FIG. 2 ). In certain aspects, the transmission and/or reception of signals by the central controller may be implemented via a bus interface of one or more processors (e.g., controller/processor  240 ) obtaining and/or outputting signals. 
     The operations  700  may begin, at block  705 , by the central controller receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle. For example, the central controller may be the wIVN controller  450  of  FIG. 4  or the wIVN controller  560  of  FIG. 5 . In one example, the wIVN controller  450  receives a request from the camera  410   a  to transmit from the camera  410   a  to the display  430  in the vehicle  400 . Although the camera  410   a  is used as an example, it should be understood that any one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , the exhaust sensor  425 , and the display  430  may send requests to the wIVN controller  450  to transmit to another one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , the exhaust sensor  425 , and the display  430 . 
     Operations  700  continue at block  710  with the central controller wirelessly transmitting, in response to the request and via a Uu interface or a PC5 interface, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device. Continuing the example, the wIVN controller  450  may wirelessly transmit, in response to the request from the camera  410   a,  via a Uu interface or a PC5 interface, one or more allocations of transmission resources to the camera  410   a . The transmission resources may include a first transmission resource for a first transmission (e.g., frames of image data) from the camera  410   a  directly to the display  430 . 
     In aspects of the present disclosure, the transmission resources of block  710  may include second transmission resources for a second transmission from the device to a first transmission relay. The allocation of the transmission resources can be provided to the devices and the first transmission relay individually or provided to both. When the transmission resources information is provided to both, the first transmission relay will receive the transmission from the device via the first transmission resources. The device and the first transmission relay may use the second transmission resources for re-transmission at the same time to the other device. This allows a combined transmission and increases the probability of the other device successfully receiving the transmission. In case there are multiple Relays in the wIVN network, all of them may be configured to perform the re-transmission of the packet using the second resources, and thus improve the probability of correct reception at the other devices of the combined signal. In another aspect of the present disclosure, the re-transmission of the packet is only initiated by the Relay or the original transmitting device if a negative acknowledgement (NACK) is received. In case a positive acknowledgement (ACK) is received for the original transmission, the second transmission resources can be released for other use, e.g., transmission of a new packet, or for interference measurements, etc. 
     According to aspects of the present disclosure, a central controller performing operations  700  may wirelessly transmit one or more other allocations of transmission resources to the first transmission relay for the first transmission relay to use for a third transmission to the other device. 
     In aspects of the present disclosure, the allocations of block  705  may include another allocation of the first transmission resources for a second transmission from the first transmission relay to the other device. 
     In aspects of the present disclosure, a central controller performing operations  700  may receive a data packet from the device and transmit the data packet to the other device. 
     According to aspects of the present disclosure, a central controller performing operations  700  may wirelessly transmit one or more other allocations of transmission resources to the device for a third transmission to a second transmission relay and wirelessly transmit one or more other allocations of transmission resources to the second transmission relay for the second transmission relay to use for a fourth transmission to the other device. 
     In aspects of the present disclosure, a central controller performing operations  700  may receive a registration request from the device prior to receiving the request to transmit. 
     According to aspects of the present disclosure, a central controller performing operations  700  may determine a wireless in-vehicle-network address of the device based on an address of the device on a wired in-vehicle-network bus to which the device is connected. 
     In aspects of the present disclosure, a central controller performing operations  700  may broadcast an indication of an address of the central controller via a device-to-device (D2D) communication link. 
     According to aspects of the present disclosure, a central controller performing operations  700  may wirelessly transmit, in response to the request and via a D2D communication link (e.g., a Uu interface or a PC5 interface), another allocation of the first transmission resources to the other device to receive the first transmission via the first transmission resources. 
     In aspects of the present disclosure, a central controller performing operations  700  may transmit, over a D2D communication link and to the device, a configuration for the measurement of interference (e.g., a configuration file indicating which frequencies to measure when and/or a command to measure one or more frequencies at one or more times); and may receive an interference measurement from the device according to the configuration. According to some aspects of the present disclosure, the central controller may transmit, to the device, a configuration update for transmitting from the device to the other device, wherein the configuration update is determined based on the interference measurement. 
       FIG. 8  is a flow diagram illustrating example operations  800  for wireless communication, in accordance with certain aspects of the present disclosure. The operations  800  may be performed, for example, by a device in a vehicle (e.g., such as the UE  120   a  in the wireless communication network  100  or the device  410   b  in the vehicle  400 ). Operations  800  may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor  280  of  FIG. 2 ). Further, the transmission and reception of signals by the device in operations  800  may be enabled, for example, by one or more antennas (e.g., antennas  252  of  FIG. 2 ). In certain aspects, the transmission and/or reception of signals by the device may be implemented via a bus interface of one or more processors (e.g., controller/processor  280 ) obtaining and/or outputting signals. 
     The operations  800  may begin, at block  805 , by the device receiving one or more allocations of transmission resources from a central controller in the vehicle. For example, the receiving device may be one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , the exhaust sensor  425 , and the display  430  of the vehicle  400  shown in  FIG. 4 . The central controller may be the wIVN controller  450 . In one example, the display  430  receives one or more allocations of transmission resources from the wIVN controller  450  in the vehicle  400 . 
     At block  810 , the device wirelessly receives a data packet from another device other than the central controller via the transmission resources. Continuing the example, the display  430  wirelessly receives a data packet from one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , and the exhaust sensor  425  via the transmission resources (i.e., the transmission resources of the one or more allocations from the wIVN controller  450  in block  805 ). 
     Operations  800  continue at block  815  with the device wirelessly receiving the data packet from a first transmission relay via the transmission resources. Continuing the example, the display  430  wirelessly receives the data packet from a first transmission relay via the transmission resources (i.e., the transmission resources of the one or more allocations from the wIVN controller  450  in block  805 ). The first transmission relay can be the relay  460  in the vehicle  400  or the BS  110   a  in the wireless communication network  100 . 
     According to aspects of the present disclosure, the one or more allocations of transmission resources of block  805  may include first transmission resources and second transmission resources; wirelessly receiving the data packet from the other device, as in block  810 , may include wirelessly receiving the data packet via the first transmission resources; and wirelessly receiving the data packet from the first transmission relay, as in block  815 , may include wirelessly receiving the data packet via the second transmission resources. 
     According to aspects of the present disclosure, wirelessly receiving the data packet from the first transmission relay, as in block  815 , may include wirelessly receiving the data packet from the central controller. 
     In aspects of the present disclosure, a device performing operations  800  may also wirelessly receive the data packet from a second transmission relay via the transmission resources. 
     According to aspects of the present disclosure, a device performing operations  800  may register with the central controller prior to receiving the one or more allocations. 
     In aspects of the present disclosure, a device performing operations  800  may determine a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected. 
     According to aspects of the present disclosure, a device performing operations  800  may power-on one or more components of the device in response to receiving the allocations. 
     In aspects of the present disclosure, wirelessly receiving the data packet from the first transmission relay as in block  815  may include receiving the data packet from the first transmission relay and the other device simultaneously. 
     According to aspects of the present disclosure, receiving the one or more allocations of the transmission resources as in block  805  may include receiving the one or more allocations of the transmission resources via a device-to-device (D2D) communication link. 
     In aspects of the present disclosure, a device performing operations  800  may receive, over a device-to-device (D2D) communication link, a configuration for the measurement of interference (e.g., a configuration file indicating which frequencies to measure when and/or a command to measure one or more frequencies at one or more times); and may report an interference measurement according to the configuration. 
       FIG. 9  is a flow diagram illustrating example operations  900  for wireless communication, in accordance with certain aspects of the present disclosure. The operations  900  may be performed, for example, by a transmission relay in a vehicle (e.g., such as the BS  110   a  in the wireless communication network  100  or the relay  460  in the vehicle  400 ). Operations  900  may be implemented as software components that are executed and run on one or more processors (e.g., controller/processor  240  of  FIG. 2 ). Further, the transmission and reception of signals by the transmission relay in operations  900  may be enabled, for example, by one or more antennas (e.g., antennas  234  of  FIG. 2 ). In certain aspects, the transmission and/or reception of signals by the transmission relay may be implemented via a bus interface of one or more processors (e.g., controller/processor  240 ) obtaining and/or outputting signals. 
     The operations  900  may begin, at block  905 , by the transmission relay receiving one or more allocations of transmission resources from a central controller in the vehicle. For example, the transmission relay may be the relay  460  that receives one or more allocations of transmission resources from the wIVN controller  450  in the vehicle  400 . 
     At block  910 , the transmission relay wirelessly receives a data packet from a first device other than the central controller via a first device-to-device (D2D) communication link on the transmission resources. Continuing the example, the relay  460  receives a data packet from one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , the exhaust sensor  425 , and the display  430  of the vehicle  400  via a first D2D communication link on the transmission resources (i.e., the transmission resources of the one or more allocations from the wIVN controller  450  in block  905 ). 
     Operations  900  continue at block  915  with the transmission relay wirelessly transmitting the data packet to a second device via a second D2D communication link on the transmission resources. Continuing the example, the relay  460  wirelessly transmits the data packet to another device, such as another one of the door sensors  405   a - b , cameras  410   a - d , in-cabin sensors  415   a - d , engine sensors  420   a - b , the exhaust sensor  425 , and the display  430  of the vehicle  400 , via a second D2D communication link on the transmission resources (i.e., the transmission resources of the one or more allocations from the wIVN controller  450  in block  905 ). 
     According to aspects of the present disclosure, the one or more allocations of transmission resources of block  905  may include first transmission resources and second transmission resources; wirelessly receiving the data packet from the first device, as in block  910 , may include wirelessly receiving the data packet via the first D2D communication link on the first transmission resources; and wirelessly transmitting the data packet to the second device, as in block  915 , may include wirelessly transmitting the data packet via the second D2D communication link on the second transmission resources. 
     In aspects of the present disclosure, wirelessly transmitting the data packet to the second device as in block  915  may include transmitting simultaneously with the first device transmitting the data packet to the second device. 
     In aspects of the present disclosure, wirelessly transmitting the data packet to the second device, as in block  915 , may include wirelessly transmitting the data packet to the central controller. 
     According to aspects of the present disclosure, a transmission relay performing operations  900  may register with the central controller prior to receiving the one or more allocations. 
     According to aspects of the present disclosure, a transmission relay performing operations  900  may determine a wireless in-vehicle-network address of the transmission relay based on a wired in-vehicle-network bus to which the transmission relay is connected. 
     In aspects of the present disclosure, a transmission relay performing operations  900  may receive, over a third D2D communication link, a configuration for the measurement of interference (e.g., a configuration file indicating which frequencies to measure when and/or a command to measure one or more frequencies at one or more times); and the transmission relay may report an interference measurement according to the configuration. According to some aspects of the present disclosure, the transmission relay may receiving a configuration update for the wirelessly transmitting the data packet as in block  915 , wherein the configuration update is determined based on the interference measurement. 
       FIG. 10  is an exemplary call flow  1000  of an exemplary wIVN, according to aspects of the present disclosure. The exemplary wIVN includes a first device (e.g., a camera or sensor)  1002 , a second device (e.g., a display or engine controller)  1004 , a central controller  1006 , and a relay  1008 . At  1010 , the first device determines to transmit data to the second device. At  1012 , the first device sends a transmit request to the central controller. At  1014 , the central controller transmits a grant of first transmission resources and optionally second transmission resources to the first device in response to the transmit request  1012 . At  1016 , the central controller optionally transmits a receive grant for the first transmission resources and third transmission resources to the second device. At  1018 , the central controller optionally transmits another receive grant to the relay for the first transmission resources or optionally the second transmission resources. At  1020 , the central controller transmits a grant of the third transmission resources to the relay. As described below, in block  1021  the first device transmits the data to the second device via the first transmission resources. In block  1021 , the first device also transmits the data and an identifier for the second device (destination ID) to the relay via the first transmission resources or the second transmission resources. The first device may send the data and the identifier in a single broadcast transmission  1022  so that both the second device and the relay receive the data and the identifier. Alternatively, the first device may send the data to the second device in a first transmission  1024  via the first transmission resources, and the first device may send the data and the identifier to the relay in a second transmission  1026  via the second transmission resources. At  1028 , the relay sends the data to the second device via the third transmission resources. 
       FIG. 11  illustrates a communications device  1100  that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in  FIG. 6 . The communications device  1100  includes a processing system  1102  coupled to a transceiver  1108 . The transceiver  1108  is configured to transmit and receive signals for the communications device  1100  via an antenna  1110 , such as the various signals as described herein. The processing system  1102  may be configured to perform processing functions for the communications device  1100 , including processing signals received and/or to be transmitted by the communications device  1100 . 
     The processing system  1102  includes a processor  1104  coupled to a computer-readable medium/memory  1112  via a bus  1106 . In certain aspects, the computer-readable medium/memory  1112  is configured to store instructions (e.g., computer-executable code) that when executed by the processor  1104 , cause the processor  1104  to perform the operations illustrated in  FIG. 6 , or other operations for performing the various techniques discussed herein for wireless in-vehicle networking. In certain aspects, computer-readable medium/memory  1112  stores code  1114  for wirelessly transmitting a data packet directly via device-to-device (D2D) communication to another device in the vehicle; code  1116  for monitoring for an acknowledgment (ACK) of the data packet; and code  1117  for deciding whether to retransmit the data packet to the other device, based on the monitoring. In certain aspects, the processor  1104  has circuitry configured to implement the code stored in the computer-readable medium/memory  1112 . The processor  1104  includes circuitry  1120  for wirelessly transmitting a data packet directly via device-to-device (D2D) communication to another device in the vehicle; circuitry  1124  for monitoring for an acknowledgment (ACK) of the data packet; and circuitry  1126  for deciding whether to retransmit the data packet to the other device, based on the monitoring. 
       FIG. 12  illustrates a communications device  1200  that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in  FIG. 7 . The communications device  1200  includes a processing system  1202  coupled to a transceiver  1208 . The transceiver  1208  is configured to transmit and receive signals for the communications device  1200  via an antenna  1210 , such as the various signals as described herein. The processing system  1202  may be configured to perform processing functions for the communications device  1200 , including processing signals received and/or to be transmitted by the communications device  1200 . 
     The processing system  1202  includes a processor  1204  coupled to a computer-readable medium/memory  1212  via a bus  1206 . In certain aspects, the computer-readable medium/memory  1212  is configured to store instructions (e.g., computer-executable code) that when executed by the processor  1204 , cause the processor  1204  to perform the operations illustrated in  FIG. 7 , or other operations for performing the various techniques discussed herein for wireless in-vehicle networking. In certain aspects, computer-readable medium/memory  1212  stores code  1214  for receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and code  1216  for wirelessly transmitting, in response to the request and via a Uu interface or a PC5 interface, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device. In certain aspects, the processor  1204  has circuitry configured to implement the code stored in the computer-readable medium/memory  1212 . The processor  1204  includes circuitry  1220  for receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and circuitry  1222  for wirelessly transmitting, in response to the request and via a Uu interface or a PC5 interface, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device. 
       FIG. 13  illustrates a communications device  1300  that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in  FIG. 8 . The communications device  1300  includes a processing system  1302  coupled to a transceiver  1308 . The transceiver  1308  is configured to transmit and receive signals for the communications device  1300  via an antenna  1310 , such as the various signals as described herein. The processing system  1302  may be configured to perform processing functions for the communications device  1300 , including processing signals received and/or to be transmitted by the communications device  1300 . 
     The processing system  1302  includes a processor  1304  coupled to a computer-readable medium/memory  1312  via a bus  1306 . In certain aspects, the computer-readable medium/memory  1312  is configured to store instructions (e.g., computer-executable code) that when executed by the processor  1304 , cause the processor  1304  to perform the operations illustrated in  FIG. 8 , or other operations for performing the various techniques discussed herein for wireless in-vehicle networking. In certain aspects, computer-readable medium/memory  1312  stores code  1314  for receiving one or more allocations of transmission resources from a central controller in the vehicle; code  1315  for wirelessly receiving a data packet from another device other than the central controller via the transmission resources; and code  1316  for wirelessly receiving the data packet from a first transmission relay via the transmission resources. In certain aspects, the processor  1304  has circuitry configured to implement the code stored in the computer-readable medium/memory  1312 . The processor  1304  includes circuitry  1320  for receiving one or more allocations of transmission resources from a central controller in the vehicle; circuitry  1322  for wirelessly receiving a data packet from another device other than the central controller via the transmission resources; and circuitry  1324  for wirelessly receiving the data packet from a first transmission relay via the transmission resources. 
       FIG. 14  illustrates a communications device  1400  that may include various components (e.g., corresponding to means-plus-function components) configured to perform operations for the techniques disclosed herein, such as the operations illustrated in  FIG. 9 . The communications device  1400  includes a processing system  1402  coupled to a transceiver  1408 . The transceiver  1408  is configured to transmit and receive signals for the communications device  1400  via an antenna  1410 , such as the various signals as described herein. The processing system  1402  may be configured to perform processing functions for the communications device  1400 , including processing signals received and/or to be transmitted by the communications device  1400 . 
     The processing system  1402  includes a processor  1404  coupled to a computer-readable medium/memory  1412  via a bus  1406 . In certain aspects, the computer-readable medium/memory  1412  is configured to store instructions (e.g., computer-executable code) that when executed by the processor  1404 , cause the processor  1404  to perform the operations illustrated in  FIG. 9 , or other operations for performing the various techniques discussed herein for wireless in-vehicle networking. In certain aspects, computer-readable medium/memory  1412  stores code  1414  for receiving one or more allocations of transmission resources from a central controller in the vehicle; code  1415  for wirelessly receiving a data packet from a first device other than the central controller via device-to-device (D2D) communication on the transmission resources; and code  1416  for wirelessly transmitting the data packet to a second device via D2D communication on the transmission resources. In certain aspects, the processor  1404  has circuitry configured to implement the code stored in the computer-readable medium/memory  1412 . The processor  1404  includes circuitry  1420  for receiving one or more allocations of transmission resources from a central controller in the vehicle; circuitry  1422  for wirelessly receiving a data packet from a first device other than the central controller via device-to-device (D2D) communication on the transmission resources; and circuitry  1424  for wirelessly transmitting the data packet to a second device via D2D communication on the transmission resources. 
     The techniques described herein may be used for various wireless communication technologies, such as NR (e.g., 5G NR), 3GPP Long Term Evolution (LTE), LTE-Advanced (LTE-A), code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal frequency division multiple access (OFDMA), single-carrier frequency division multiple access (SC-FDMA), time division synchronous code division multiple access (TD-SCDMA), and other networks. The terms “network” and “system” are often used interchangeably. A CDMA network may implement a radio technology such as Universal Terrestrial Radio Access (UTRA), cdma2000, etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. cdma2000 covers IS-2000, IS-95 and IS-856 standards. A TDMA network may implement a radio technology such as Global System for Mobile Communications (GSM). An OFDMA network may implement a radio technology such as NR (e.g. 5G RA), Evolved UTRA (E-UTRA), Ultra Mobile Broadband (UMB), IEEE 802.11 (Wi-Fi), IEEE 802.16 (WiMAX), IEEE 802.20, Flash-OFDMA, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunication System (UMTS). LTE and LTE-A are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A and GSM are described in documents from an organization named “3rd Generation Partnership Project” (3GPP). cdma2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2). NR is an emerging wireless communications technology under development. 
     The techniques described herein may be used for the wireless networks and radio technologies mentioned above as well as other wireless networks and radio technologies. For clarity, while aspects may be described herein using terminology commonly associated with 3G, 4G, and/or 5G wireless technologies, aspects of the present disclosure can be applied in other generation-based communication systems. 
     In 3GPP, the term “cell” can refer to a coverage area of a Node B (NB) and/or a NB subsystem serving this coverage area, depending on the context in which the term is used. In NR systems, the term “cell” and BS, next generation NodeB (gNB or gNodeB), access point (AP), distributed unit (DU), carrier, or transmission reception point (TRP) may be used interchangeably. A BS may provide communication coverage for a macro cell, a pico cell, a femto cell, and/or other types of cells. A macro cell may cover a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscription. A pico cell may cover a relatively small geographic area and may allow unrestricted access by UEs with service subscription. A femto cell may cover a relatively small geographic area (e.g., a home) and may allow restricted access by UEs having an association with the femto cell (e.g., UEs in a Closed Subscriber Group (CSG), UEs for users in the home, etc.). A BS for a macro cell may be referred to as a macro BS. A BS for a pico cell may be referred to as a pico BS. ABS for a femto cell may be referred to as a femto BS or a home BS. 
     A UE may also be referred to as a mobile station, a terminal, an access terminal, a subscriber unit, a station, a Customer Premises Equipment (CPE), a cellular phone, a smart phone, a personal digital assistant (PDA), a wireless modem, a wireless communication device, a handheld device, a laptop computer, a cordless phone, a wireless local loop (WLL) station, a tablet computer, a camera, a gaming device, a netbook, a smartbook, an ultrabook, an appliance, a medical device or medical equipment, a biometric sensor/device, a wearable device such as a smart watch, smart clothing, smart glasses, a smart wrist band, smart jewelry (e.g., a smart ring, a smart bracelet, etc.), an entertainment device (e.g., a music device, a video device, a satellite radio, etc.), a vehicular component or sensor, a smart meter/sensor, industrial manufacturing equipment, a global positioning system device, or any other suitable device that is configured to communicate via a wireless or wired medium. Some UEs may be considered machine-type communication (MTC) devices or evolved MTC (eMTC) devices. MTC and eMTC UEs include, for example, robots, drones, remote devices, sensors, meters, monitors, location tags, etc., that may communicate with a BS, another device (e.g., remote device), or some other entity. A wireless node may provide, for example, connectivity for or to a network (e.g., a wide area network such as Internet or a cellular network) via a wired or wireless communication link. Some UEs may be considered Internet-of-Things (IoT) devices, which may be narrowband IoT (NB-IoT) devices. 
     Certain wireless networks (e.g., LTE) utilize orthogonal frequency division multiplexing (OFDM) on the downlink and single-carrier frequency division multiplexing (SC-FDM) on the uplink. OFDM and SC-FDM partition the system bandwidth into multiple (K) orthogonal subcarriers, which are also commonly referred to as tones, bins, etc. Each subcarrier may be modulated with data. In general, modulation symbols are sent in the frequency domain with OFDM and in the time domain with SC-FDM. The spacing between adjacent subcarriers may be fixed, and the total number of subcarriers (K) may be dependent on the system bandwidth. For example, the spacing of the subcarriers may be 15 kHz and the minimum resource allocation (called a “resource block” (RB)) may be 12 subcarriers (or 180 kHz). Consequently, the nominal Fast Fourier Transfer (FFT) size may be equal to 128, 256, 512, 1024 or 2048 for system bandwidth of 1.25, 2.5, 5, 10, or 20 megahertz (MHz), respectively. The system bandwidth may also be partitioned into subbands. For example, a subband may cover 1.08 MHz (e.g., 6 RBs), and there may be 1, 2, 4, 8, or 16 subbands for system bandwidth of 1.25, 2.5, 5, 10 or 20 MHz, respectively. In LTE, the basic transmission time interval (TTI) or packet duration is the 1 ms subframe. 
     NR may utilize OFDM with a CP on the uplink and downlink and include support for half-duplex operation using TDD. In NR, a subframe is still 1 ms, but the basic TTI is referred to as a slot. A subframe contains a variable number of slots (e.g., 1, 2, 4, 8, 16, . . . slots) depending on the subcarrier spacing. The NR RB is 12 consecutive frequency subcarriers. NR may support a base subcarrier spacing of 15 KHz and other subcarrier spacing may be defined with respect to the base subcarrier spacing, for example, 30 kHz, 60 kHz, 120 kHz, 240 kHz, etc. The symbol and slot lengths scale with the subcarrier spacing. The CP length also depends on the subcarrier spacing. Beamforming may be supported and beam direction may be dynamically configured. MIMO transmissions with precoding may also be supported. In some examples, MIMO configurations in the DL may support up to 8 transmit antennas with multi-layer DL transmissions up to 8 streams and up to 2 streams per UE. In some examples, multi-layer transmissions with up to 2 streams per UE may be supported. Aggregation of multiple cells may be supported with up to 8 serving cells. 
     In some examples, access to the air interface may be scheduled. A scheduling entity (e.g., a BS) allocates resources for communication among some or all devices and equipment within its service area or cell. The scheduling entity may be responsible for scheduling, assigning, reconfiguring, and releasing resources for one or more subordinate entities. That is, for scheduled communication, subordinate entities utilize resources allocated by the scheduling entity. Base stations are not the only entities that may function as a scheduling entity. In some examples, a UE may function as a scheduling entity and may schedule resources for one or more subordinate entities (e.g., one or more other UEs), and the other UEs may utilize the resources scheduled by the UE for wireless communication. In some examples, a UE may function as a scheduling entity in a peer-to-peer (P2P) network, and/or in a mesh network. In a mesh network example, UEs may communicate directly with one another in addition to communicating with a scheduling entity. 
     In some examples, two or more subordinate entities (e.g., UEs) may communicate with each other using sidelink signals. Real-world applications of such sidelink communications may include public safety, proximity services, UE-to-network relaying, vehicle-to-vehicle (V2V) communications, Internet of Everything (IoE) communications, IoT communications, mission-critical mesh, and/or various other suitable applications. Generally, a sidelink signal may refer to a signal communicated from one subordinate entity (e.g., UE 1 ) to another subordinate entity (e.g., UE 2 ) without relaying that communication through the scheduling entity (e.g., UE or BS), even though the scheduling entity may be utilized for scheduling and/or control purposes. In some examples, the sidelink signals may be communicated using a licensed spectrum (unlike wireless local area networks, which typically use an unlicensed spectrum). 
     The methods disclosed herein comprise one or more steps or actions for achieving the methods. The method steps and/or actions may be interchanged with one another without departing from the scope of the claims. In other words, unless a specific order of steps or actions is specified, the order and/or use of specific steps and/or actions may be modified without departing from the scope of the claims. 
     As used herein, a phrase referring to “at least one of” a list of items refers to any combination of those items, including single members. As an example, “at least one of: a, b, or c” is intended to cover a, b, c, a-b, a-c, b-c, and a-b-c, as well as any combination with multiples of the same element (e.g., a-a, a-a-a, a-a-b, a-a-c, a-b-b, a-c-c, b-b, b-b-b, b-b-c, c-c, and c-c-c or any other ordering of a, b, and c). 
     As used herein, the term “determining” encompasses a wide variety of actions. For example, “determining” may include calculating, computing, processing, deriving, investigating, looking up (e.g., looking up in a table, a database or another data structure), ascertaining and the like. Also, “determining” may include receiving (e.g., receiving information), accessing (e.g., accessing data in a memory) and the like. Also, “determining” may include resolving, selecting, choosing, establishing and the like. 
     The previous description is provided to enable any person skilled in the art to practice the various aspects described herein. Various modifications to these aspects will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but is to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular is not intended to mean “one and only one” unless specifically so stated, but rather “one or more.” Unless specifically stated otherwise, the term “some” refers to one or more. All structural and functional equivalents to the elements of the various aspects described throughout this disclosure that are known or later come to be known to those of ordinary skill in the art are expressly incorporated herein by reference and are intended to be encompassed by the claims. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. No claim element is to be construed under the provisions of 35 U.S.C. § 112(f) unless the element is expressly recited using the phrase “means for” or, in the case of a method claim, the element is recited using the phrase “step for.” 
     The various operations of methods described above may be performed by any suitable means capable of performing the corresponding functions. The means may include various hardware and/or software component(s) and/or module(s), including, but not limited to a circuit, an application specific integrated circuit (ASIC), or processor. Generally, where there are operations illustrated in figures, those operations may have corresponding counterpart means-plus-function components with similar numbering. 
     The various illustrative logical blocks, modules and circuits described in connection with the present disclosure may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device (PLD), discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any commercially available processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration. 
     If implemented in hardware, an example hardware configuration may comprise a processing system in a wireless node. The processing system may be implemented with a bus architecture. The bus may include any number of interconnecting buses and bridges depending on the specific application of the processing system and the overall design constraints. The bus may link together various circuits including a processor, machine-readable media, and a bus interface. The bus interface may be used to connect a network adapter, among other things, to the processing system via the bus. The network adapter may be used to implement the signal processing functions of the PHY layer. In the case of a user terminal  120  (see  FIG. 1 ), a user interface (e.g., keypad, display, mouse, joystick, etc.) may also be connected to the bus. The bus may also link various other circuits such as timing sources, peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further. The processor may be implemented with one or more general-purpose and/or special-purpose processors. Examples include microprocessors, microcontrollers, DSP processors, and other circuitry that can execute software. Those skilled in the art will recognize how best to implement the described functionality for the processing system depending on the particular application and the overall design constraints imposed on the overall system. 
     If implemented in software, the functions may be stored or transmitted over as one or more instructions or code on a computer readable medium. Software shall be construed broadly to mean instructions, data, or any combination thereof, whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise. Computer-readable media include both computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. The processor may be responsible for managing the bus and general processing, including the execution of software modules stored on the machine-readable storage media. A computer-readable storage medium may be coupled to a processor such that the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. By way of example, the machine-readable media may include a transmission line, a carrier wave modulated by data, and/or a computer readable storage medium with instructions stored thereon separate from the wireless node, all of which may be accessed by the processor through the bus interface. Alternatively, or in addition, the machine-readable media, or any portion thereof, may be integrated into the processor, such as the case may be with cache and/or general register files. Examples of machine-readable storage media may include, by way of example, RAM (Random Access Memory), flash memory, ROM (Read Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable Programmable Read-Only Memory), EEPROM (Electrically Erasable Programmable Read-Only Memory), registers, magnetic disks, optical disks, hard drives, or any other suitable storage medium, or any combination thereof. The machine-readable media may be embodied in a computer-program product. 
     A software module may comprise a single instruction, or many instructions, and may be distributed over several different code segments, among different programs, and across multiple storage media. The computer-readable media may comprise a number of software modules. The software modules include instructions that, when executed by an apparatus such as a processor, cause the processing system to perform various functions. The software modules may include a transmission module and a receiving module. Each software module may reside in a single storage device or be distributed across multiple storage devices. By way of example, a software module may be loaded into RAM from a hard drive when a triggering event occurs. During execution of the software module, the processor may load some of the instructions into cache to increase access speed. One or more cache lines may then be loaded into a general register file for execution by the processor. When referring to the functionality of a software module below, it will be understood that such functionality is implemented by the processor when executing instructions from that software module. 
     Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL), or wireless technologies such as infrared (IR), radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk, and Blu-ray® disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Thus, in some aspects computer-readable media may comprise non-transitory computer-readable media (e.g., tangible media). In addition, for other aspects computer-readable media may comprise transitory computer- readable media (e.g., a signal). Combinations of the above should also be included within the scope of computer-readable media. 
     Thus, certain aspects may comprise a computer program product for performing the operations presented herein. For example, such a computer program product may comprise a computer-readable medium having instructions stored (and/or encoded) thereon, the instructions being executable by one or more processors to perform the operations described herein, for example, instructions for performing the operations described herein and illustrated in  FIG. 6 ,  FIG. 7 ,  FIG. 8 , and/or  FIG. 9 . 
     Further, it should be appreciated that modules and/or other appropriate means for performing the methods and techniques described herein can be downloaded and/or otherwise obtained by a user terminal and/or base station as applicable. For example, such a device can be coupled to a server to facilitate the transfer of means for performing the methods described herein. Alternatively, various methods described herein can be provided via storage means (e.g., RAM, ROM, a physical storage medium such as a compact disc (CD) or floppy disk, etc.), such that a user terminal and/or base station can obtain the various methods upon coupling or providing the storage means to the device. Moreover, any other suitable technique for providing the methods and techniques described herein to a device can be utilized. 
     It is to be understood that the claims are not limited to the precise configuration and components illustrated above. Various modifications, changes and variations may be made in the arrangement, operation and details of the methods and apparatus described above without departing from the scope of the claims. 
     Example Aspects of Wireless In-Vehicle Networking Architecture 
     In a first aspect, a method for wireless communications performed by a device in a vehicle, includes: wirelessly transmitting a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle; monitoring for an acknowledgment (ACK) of the data packet; deciding whether to retransmit the data packet to the other device, based on the monitoring; and wirelessly transmitting the data packet to a transmission relay, wherein an intended destination of the data packet is the other device, wherein the monitoring for the ACK comprises monitoring for a first ACK from the other device and a second ACK from the transmission relay. 
     In a second aspect, in combination with the first aspect, wirelessly transmitting the data packet directly via the first D2D communication link to the other device comprises transmitting simultaneously with a transmission relay transmitting the data packet to the other device. 
     In a third aspect, in combination with one or more of the first and second aspects, the method includes receiving an allocation of first transmission resources from a central controller in the vehicle, wherein wirelessly transmitting the data packet directly to the other device comprises transmitting the data packet via the first transmission resources; and receiving an allocation of second transmission resources from the central controller, wherein wirelessly transmitting the data packet to the transmission relay comprises transmitting the data packet via the second transmission resources. 
     In a fourth aspect, in combination with the third aspect, the method includes: transmitting a request for the allocation of first transmission resources and the allocation of second transmission resources to the central controller. 
     In a fifth aspect, in combination with the third aspect, the method includes: registering with the central controller using pre-configured security certificates prior to receiving the allocation of the first transmission resources or the allocation of the second transmission resources. 
     In a sixth aspect, in combination with the third aspect, receiving the allocation of the first transmission resources comprises receiving the allocation of the first transmission resources via a second D2D communication link; and receiving the allocation of the second transmission resources comprises receiving the allocation of the second transmission resources via the second D2D communication link or a third D2D communication link. 
     In a seventh aspect, in combination with the sixth aspect, the method includes discovering an address of the central controller based on a broadcast via one of the first, the second, the third, or a fourth D2D communication links. 
     In an eighth aspect, in combination with the one or more of the first through seventh aspects, the method includes: determining a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a ninth aspect, in combination with one or more of the first through eighth aspects, the method includes: receiving, over the first or a second D2D communication link, a configuration for measurement of interference; and reporting an interference measurement according to the configuration. 
     In a tenth aspect, in combination with the ninth aspect, the method includes receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the reporting the interference measurement. 
     In an eleventh aspect, a method for wireless communication performed by a central controller in a vehicle, includes: receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and wirelessly transmitting, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device, wherein the transmission resources further comprise second transmission resources for a second transmission from the device to a first transmission relay. 
     In a twelfth aspect, in combination with the eleventh aspect, the allocations comprise another allocation of the first transmission resources for a second transmission from the first transmission relay to the other device. 
     In a thirteenth aspect, in combination with one or more of the eleventh and the twelfth aspects, the method includes wirelessly transmitting one or more other allocations of transmission resources to the first transmission relay for the first transmission relay to use for a third transmission to the other device. 
     In a fourteenth aspect, in combination with one or more of the eleventh through the twelfth aspects, the method includes: wirelessly transmitting one or more other allocations of transmission resources to the device for a third transmission to a second transmission relay; and wirelessly transmitting one or more other allocations of transmission resources to the second transmission relay for the second transmission relay to use for a fourth transmission to the other device. 
     In a fifteenth aspect, in combination with one or more of the eleventh through fourteenth aspects, the method includes receiving a registration request from the device prior to receiving the request to transmit. 
     In a sixteenth aspect, in combination with one or more of the eleventh through fifteenth aspects, the method includes: determining a wireless in-vehicle-network address of the device based on an address of the device on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a seventeenth aspect, in combination with one or more of the eleventh through sixteenth aspects, the method includes: wirelessly transmitting, in response to the request and via a device-to-device (D2D) communication link, another allocation of the first transmission resources to the other device to receive the first transmission via the first transmission resources; transmitting, over a device-to-device (D2D) communication link and to the device, a configuration for measurement of interference; and receiving an interference measurement from the device according to the configuration. 
     In an eighteenth aspect, in combination with the seventeenth aspect, the method includes transmitting, to the device, a configuration update for transmitting from the device to the other device, wherein the configuration update is determined based on the interference measurement. 
     In a nineteenth aspect, a method for wireless communications performed by a device in a vehicle, includes: receiving one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receiving a data packet from another device other than the central controller via the transmission resources; and wirelessly receiving the data packet from a first transmission relay via the transmission resources. 
     In a twentieth aspect, in combination with the nineteenth aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the other device comprises wirelessly receiving the data packet via the first transmission resources; and wirelessly receiving the data packet from the first transmission relay comprises wirelessly receiving the data packet via the second transmission resources. 
     In a twenty-first aspect, in combination with the nineteenth aspect, the method includes registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a twenty-second aspect, in combination with the nineteenth aspect, the method includes determining a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a twenty-third aspect, in a wireless communications system, in combination with one or more of the nineteenth through twenty-second aspects, the method includes powering-on one or more components of the device in response to receiving the allocations. 
     In a twenty-fourth aspect, in combination with one or more of the nineteenth through twenty-third aspects, the method includes wirelessly receiving the data packet from the first transmission relay comprises receiving the data packet from the first transmission relay and the other device simultaneously. 
     In a twenty-fifth aspect, a method for wireless communications performed by a transmission relay in a vehicle, includes: receiving one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receiving a data packet from a first device via a first device-to-device (D2D) communication link on the transmission resources; and wirelessly transmitting the data packet to a second device via a second D2D communication link on the transmission resources. 
     In a 26 th  aspect, in combination with the twenty-fifth aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the first device comprises wirelessly receiving the data packet via the first D2D communication link on the first transmission resources; and wirelessly transmitting the data packet to the second device comprises wirelessly transmitting the data packet via the second D2D communication link on the second transmission resources. 
     In a 27 th  aspect, in combination with the twenty-fifth aspect, wirelessly transmitting the data packet to the second device comprises transmitting simultaneously with the first device transmitting the data packet to the second device. 
     In a 28 th  aspect, in combination with one or more of the twenty-fifth through 27 th  aspects, the method includes: registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 29 th  aspect, in combination with one or more of the twenty-fifth through 28 th  aspects, the method includes: determining a wireless in-vehicle-network address of the transmission relay based on a wired in-vehicle-network bus to which the transmission relay is connected, wherein determining the wireless in-vehicle-network address of the transmission relay comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 30 th  aspect, in combination with one or more of the twenty-fifth through 29 th  aspects, the method includes: receiving, over a third D2D communication link, a configuration for measurement of interference; reporting an interference measurement according to the configuration; and receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the interference measurement. 
     In a 31 st  aspect, a method for communications performed by a device in a vehicle, includes: wirelessly transmitting a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle; monitoring for an acknowledgment (ACK) of the data packet; deciding whether to retransmit the data packet to the other device, based on the monitoring; and wirelessly transmitting the data packet to a transmission relay, wherein an intended destination of the data packet is the other device, wherein the monitoring for the ACK comprises monitoring for a first ACK from the other device and a second ACK from the transmission relay. 
     In a 32 nd  aspect, in combination with the 31 st  aspect, wirelessly transmitting the data packet directly via the first D2D communication link to the other device comprises transmitting simultaneously with a transmission relay transmitting the data packet to the other device. 
     In a 33 rd  aspect, in combination with one or more of the 31 st  through 32 nd  aspects, the method includes: receiving an allocation of first transmission resources from a central controller in the vehicle, wherein wirelessly transmitting the data packet directly to the other device comprises transmitting the data packet via the first transmission resources; and receiving an allocation of second transmission resources from the central controller, wherein wirelessly transmitting the data packet to the transmission relay comprises transmitting the data packet via the second transmission resources. 
     In a 34 th  aspect, in combination with one or more of the 31 st  through 33 rd  aspects, the method includes: transmitting a request for the allocation of first transmission resources and the allocation of second transmission resources to the central controller. 
     In a 35 th  aspect, in combination with one or more of the 31 st  through 34 th  aspects, the method includes: registering with the central controller using pre-configured security certificates prior to receiving the allocation of the first transmission resources or the allocation of the second transmission resources. 
     In a 36 th  aspect, in combination with one or more of the 31 st  through 35 th  aspects, the method includes: receiving the allocation of the first transmission resources comprises receiving the allocation of the first transmission resources via a second D2D communication link; and receiving the allocation of the second transmission resources comprises receiving the allocation of the second transmission resources via the second D2D communication link or a third D2D communication link. 
     In a 37 th  aspect, in combination with one or more of the 31 st  through 36 th  aspects, the method includes: discovering an address of the central controller based on a broadcast via one of the first, the second, the third, or a fourth D2D communication links. 
     In a 38 th  aspect, in combination with one or more of the 31 st  through 37 th  aspects, the method includes: determining a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 39 th  aspect, in combination with one or more of the 31 st  through 38 th  aspects, the method includes: receiving, over the first or a second D2D communication link, a configuration for measurement of interference; and reporting an interference measurement according to the configuration. 
     In a 40 th  aspect, in combination with one or more of the 31 st  through 39 th  aspects, the method includes: receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the reporting the interference measurement. 
     In a 41 st  aspect, a method for wireless communications performed by a central controller in a vehicle, includes: receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and wirelessly transmitting, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device, wherein the transmission resources further comprise second transmission resources for a second transmission from the device to a first transmission relay. 
     In a 42 nd  aspect, in combination with the 41 st  aspect, the allocations comprise another allocation of the first transmission resources for a second transmission from the first transmission relay to the other device. 
     In a 43 rd  aspect, in combination with one or more of the 41 st  through 42 nd  aspects, the method includes: wirelessly transmitting one or more other allocations of transmission resources to the first transmission relay for the first transmission relay to use for a third transmission to the other device. 
     In a 44 th  aspect, in combination with one or more of the 41 st  through 43 rd  aspects, the method includes: wirelessly transmitting one or more other allocations of transmission resources to the device for a third transmission to a second transmission relay; and wirelessly transmitting one or more other allocations of transmission resources to the second transmission relay for the second transmission relay to use for a fourth transmission to the other device. 
     In a 45 th  aspect, in combination with one or more of the 41 st  through 44 th  aspects, the method includes: receiving a registration request from the device prior to receiving the request to transmit. 
     In a 46 th  aspect, in combination with one or more of the 41 st  through 45 th  aspects, the method includes: determining a wireless in-vehicle-network address of the device based on an address of the device on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 47 th  aspect, in combination with one or more of the 41 st  through 46 th  aspects, the method includes: wirelessly transmitting, in response to the request and via a device-to-device (D2D) communication link, another allocation of the first transmission resources to the other device to receive the first transmission via the first transmission resources; transmitting, over a device-to-device (D2D) communication link and to the device, a configuration for measurement of interference; and receiving an interference measurement from the device according to the configuration. 
     In a 48 th  aspect, in combination with one or more of the 41 st  through 47 th  aspects, the method includes: transmitting, to the device, a configuration update for transmitting from the device to the other device, wherein the configuration update is determined based on the interference measurement. 
     In a 49 th  aspect, a method for wireless communications performed by a device in a vehicle, includes: receiving one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receiving a data packet from another device other than the central controller via the transmission resources; and wirelessly receiving the data packet from a first transmission relay via the transmission resources. 
     In a 50 th  aspect, in combination with the 49 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the other device comprises wirelessly receiving the data packet via the first transmission resources; and wirelessly receiving the data packet from the first transmission relay comprises wirelessly receiving the data packet via the second transmission resources. 
     In a 51 st  aspect, in combination with one or more of the 49 th  through 50 th  aspects, the method includes: registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 52 nd  aspect, in combination with one or more of the 49 th  through 51 st  aspects, the method includes: determining a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 53 rd  aspect, in combination with one or more of the 49 th  through 52 nd  aspects, the method includes: powering-on one or more components of the device in response to receiving the allocations. 
     In a 54 th  aspect, in combination with one or more of the 49 th  through 53 rd  aspects, the apparatus includes means for transmitting to the UE the index corresponding to the CSI-RS pattern prior to transmitting the CSI-RSs using the CSI-RS pattern. 
     In a 55 th  aspect, a method for wireless communications performed by a transmission relay in a vehicle, includes: receiving one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receiving a data packet from a first device via a first device-to-device (D2D) communication link on the transmission resources; and wirelessly transmitting the data packet to a second device via a second D2D communication link on the transmission resources. 
     In a 56 th  aspect, in combination with the 55 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the first device comprises wirelessly receiving the data packet via the first D2D communication link on the first transmission resources; and wirelessly transmitting the data packet to the second device comprises wirelessly transmitting the data packet via the second D2D communication link on the second transmission resources. 
     In a 57 th  aspect, in combination with one or more of the 55 th  through 56 th  aspects, wirelessly transmitting the data packet to the second device comprises transmitting simultaneously with the first device transmitting the data packet to the second device. 
     In a 58 th  aspect, in combination with one or more of the 55 th  through 57 th  aspects, the method includes: registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 59 th  aspect, in combination with one or more of the 55 th  through 58 th  aspects, the method includes: determining a wireless in-vehicle-network address of the transmission relay based on a wired in-vehicle-network bus to which the transmission relay is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 60 th  aspect, in combination with one or more of the 55 th  through  59   th  aspects, the method includes: receiving, over a third D2D communication link, a configuration for measurement of interference; reporting an interference measurement according to the configuration; and receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the interference measurement. 
     In a 61 st  aspect, in a wireless communications system, an apparatus includes a memory; and a processor coupled to the memory and configured to: wirelessly transmit a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle; monitoring for an acknowledgment (ACK) of the data packet; deciding whether to retransmit the data packet to the other device, based on the monitoring; and wirelessly transmitting the data packet to a transmission relay, wherein an intended destination of the data packet is the other device, wherein the monitoring for the ACK comprises monitoring for a first ACK from the other device and a second ACK from the transmission relay. 
     In a 62 nd  aspect, in combination with the 61 st  aspect, the processor is further configured to: wirelessly transmit the data packet directly via the first D2D communication link to the other device by transmitting simultaneously with a transmission relay transmitting the data packet to the other device. 
     In a 63 rd  aspect, in combination with the 62 nd  aspect, the processor is further configured to: receive an allocation of first transmission resources from a central controller in the vehicle, wherein wirelessly transmitting the data packet directly to the other device comprises transmitting the data packet via the first transmission resources; and receive an allocation of second transmission resources from the central controller, wherein wirelessly transmitting the data packet to the transmission relay comprises transmitting the data packet via the second transmission resources 
     In a 64 th  aspect, in combination with the 63 rd  aspect, the processor is further configured to: transmit a request for the allocation of first transmission resources and the allocation of second transmission resources to the central controller. 
     In a 65 th  aspect, in combination with one or more of the 63 rd  through 64 th  aspects, the processor is further configured to: register with the central controller using pre-configured security certificates prior to receiving the allocation of the first transmission resources or the allocation of the second transmission resources. 
     In a 66 th  aspect, in combination with one or more of the 63 rd  through 65 th  aspects, the processor is further configured to: receive the allocation of the first transmission resources by receiving the allocation of the first transmission resources via a second D2D communication link; and receive the allocation of the second transmission resources by receiving the allocation of the second transmission resources via the second D2D communication link or a third D2D communication link. 
     In a 67 th  aspect, in combination with the 66 th  aspect, the processor is further configured to: discover an address of the central controller based on a broadcast via one of the first, the second, the third, or a fourth D2D communication links. 
     In a 68 th  aspect, in combination with one or more of the 61 st  through 67 th  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected; and wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 69 th  aspect, in combination with one or more of the 61 st  through 68 th  aspects, the processor is further configured to: receive, over the first or a second D2D communication link, a configuration for measurement of interference; and report an interference measurement according to the configuration. 
     In a 70 th  aspect, in combination with the 69 th  aspect, the processor is further configured to: receive a configuration update for wirelessly transmitting the data packet, wherein the configuration update is determined based on reporting the interference measurement. 
     In a 71 st  aspect, in a wireless communications system, an apparatus includes a memory; and a processor coupled to the memory and configured to: receive, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and wirelessly transmit, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device, wherein the transmission resources further comprise second transmission resources for a second transmission from the device to a first transmission relay. 
     In a 72 nd  aspect, in combination with the 71 st  aspect, the allocations comprise another allocation of the first transmission resources for a second transmission from the first transmission relay to the other device. 
     In a 73 rd  aspect, in combination with one or more of the 71 st  through 72 nd  aspects, the processor is further configured to: wirelessly transmitting one or more other allocations of transmission resources to the first transmission relay for the first transmission relay to use for a third transmission to the other device. 
     In a 74 th  aspect, in combination with one or more of the 71 st  through 73 rd  aspects, the processor is further configured to: wirelessly transmit one or more other allocations of transmission resources to the device for a third transmission to a second transmission relay; and wirelessly transmit one or more other allocations of transmission resources to the second transmission relay for the second transmission relay to use for a fourth transmission to the other device. 
     In a 75 th  aspect, in combination with one or more of the 71 st  through 74 th  aspects, the processor is further configured to: receive a registration request from the device prior to receiving the request to transmit. 
     In a 76 th  aspect, in combination with one or more of the 71 st  through 75 th  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the device based on an address of the device on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 77 th  aspect, in combination with one or more of the 71 st  through 76 th  aspects, the processor is further configured to: wirelessly transmit, in response to the request and via a device-to-device (D2D) communication link, another allocation of the first transmission resources to the other device to receive the first transmission via the first transmission resources; transmit, over a device-to-device (D2D) communication link and to the device, a configuration for measurement of interference; and receive an interference measurement from the device according to the configuration. 
     In a 78 th  aspect, in combination with the 77 th  aspect, the processor is further configured to: transmit, to the device, a configuration update for transmitting from the device to the other device, wherein the configuration update is determined based on the interference measurement. 
     In a 79 th  aspect, in a wireless communications system, an apparatus includes a memory; and a processor coupled to the memory and configured to: receive one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receive a data packet from another device other than the central controller via the transmission resources; and wirelessly receive the data packet from a first transmission relay via the transmission resources. 
     In an 80 th  aspect, in combination with the 79 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the other device comprises wirelessly receiving the data packet via the first transmission resources; and wirelessly receiving the data packet from the first transmission relay comprises wirelessly receiving the data packet via the second transmission resources. 
     In an 81 st  aspect, in combination with one or more of the 79 th  through 80 th  aspects, the processor is further configured to: register with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In an 82 nd  aspect, in combination with one or more of the 79 th  through 81 st  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the apparatus is connected, wherein determining the wireless in-vehicle-network address of the apparatus comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In an 83 rd  aspect, in combination with one or more of the 79 th  through 82 nd  aspects, the processor is further configured to: power-on one or more components of the apparatus in response to receiving the allocations. 
     In an 84 th  aspect, in combination with one or more of the 79 th  through 83 rd  aspects, wirelessly receiving the data packet from the first transmission relay comprises receiving the data packet from the first transmission relay and the other device simultaneously. 
     In an 85 th  aspect, in a wireless communications system, an apparatus includes a memory; and a processor coupled to the memory and configured to: receive one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receive a data packet from a first device via a first device-to-device (D2D) communication link on the transmission resources; and wirelessly transmit the data packet to a second device via a second D2D communication link on the transmission resources. 
     In an 86 th  aspect, in combination with the 85 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the first device comprises wirelessly receiving the data packet via the first D2D communication link on the first transmission resources; and wirelessly transmitting the data packet to the second device comprises wirelessly transmitting the data packet via the second D2D communication link on the second transmission resources. 
     In an 87 th  aspect, in combination with one or more of the 85 th  through 86 th  aspects, wirelessly transmitting the data packet to the second device comprises transmitting simultaneously with the first device transmitting the data packet to the second device. 
     In an 88 th  aspect, in combination with one or more of the 85 th  through 87 th  aspects, the processor is further configured to: register with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In an 89 th  aspect, in combination with one or more of the 85 th  through 88 th  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the apparatus is connected, wherein determining the wireless in-vehicle-network address of the apparatus comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 90 th  aspect, in combination with one or more of the 85 th  through 89 th  aspects, the processor is further configured to: receive, over a third D2D communication link, a configuration for measurement of interference; report an interference measurement according to the configuration; and receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the interference measurement. 
     In a 91 st  aspect, in a wireless communications system, an apparatus in a vehicle includes a memory; and a processor coupled to the memory and configured to: wirelessly transmit a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle; monitor for an acknowledgment (ACK) of the data packet; deciding whether to retransmit the data packet to the other device, based on whether the ACK was monitored; and wirelessly transmit the data packet to a transmission relay, wherein an intended destination of the data packet is the other device, wherein monitoring for the ACK comprises monitoring for a first ACK from the other device and a second ACK from the transmission relay. 
     In a 92 nd  aspect, in combination with the  91   st  aspect, wirelessly transmitting the data packet directly via the first D2D communication link to the other device comprises transmitting simultaneously with a transmission relay transmitting the data packet to the other device. 
     In a 93 rd  aspect, in combination with one or more of the  91   st  through  92   nd  aspects, the processor is further configured to: receive an allocation of first transmission resources from a central controller in the vehicle, wherein wirelessly transmitting the data packet directly to the other device comprises transmitting the data packet via the first transmission resources; and receive an allocation of second transmission resources from the central controller, wherein wirelessly transmitting the data packet to the transmission relay comprises transmitting the data packet via the second transmission resources. 
     In a  94   th  aspect, in combination with one or more of the  91   st  through  93   rd  aspects, the processor is further configured to: transmit a request for the allocation of first transmission resources and the allocation of second transmission resources to the central controller. 
     In a 95 th  aspect, in combination with one or more of the 91 st  through 94 th  aspects, the processor is further configured to: register with the central controller using pre-configured security certificates prior to receiving the allocation of the first transmission resources or the allocation of the second transmission resources. 
     In a 96 th  aspect, in combination with one or more of the 91 st  through 95 th  aspects, receiving the allocation of the first transmission resources comprises receiving the allocation of the first transmission resources via a second D2D communication link; and receiving the allocation of the second transmission resources comprises receiving the allocation of the second transmission resources via the second D2D communication link or a third D2D communication link. 
     In a 97 th  aspect, in combination with one or more of the 91 st  through 96 th  aspects, the processor is further configured to: discover an address of the central controller based on a broadcast via one of the first, the second, the third, or a fourth D2D communication links. 
     In a 98 th  aspect, in combination with one or more of the 91 st  through 97 th  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the apparatus is connected, wherein determining the wireless in-vehicle-network address of the apparatus comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 99 th  aspect, in combination with one or more of the 91 st  through 98 th  aspects, the processor is further configured to: receive, over the first or a second D2D communication link, a configuration for measurement of interference; and report an interference measurement according to the configuration. 
     In a 100 th  aspect, in combination with one or more of the 91 st  through 99 th  aspects, the processor is further configured to: receive a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the reporting the interference measurement. 
     In a 101 st  aspect, in a wireless communications system, an apparatus in a vehicle includes a memory; and a processor coupled to the memory and configured to: receive, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and wirelessly transmit, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device, wherein the transmission resources further comprise second transmission resources for a second transmission from the device to a first transmission relay. 
     In a 102 nd  aspect, in combination with the 101 st  aspect, the allocations comprise another allocation of the first transmission resources for a second transmission from the first transmission relay to the other device. 
     In a 103 rd  aspect, in combination with one or more of the 101 st  through 102 nd  aspects, the processor is further configured to: wirelessly transmit one or more other allocations of transmission resources to the first transmission relay for the first transmission relay to use for a third transmission to the other device. 
     In a 104 th  aspect, in combination with one or more of the 101 st  through 103 rd  aspects, the processor is further configured to: wirelessly transmit one or more other allocations of transmission resources to the device for a third transmission to a second transmission relay; and wirelessly transmit one or more other allocations of transmission resources to the second transmission relay for the second transmission relay to use for a fourth transmission to the other device. 
     In a 105 th  aspect, in combination with one or more of the 101 st  through 104 th  aspects, the processor is further configured to: receive a registration request from the device prior to receiving the request to transmit. 
     In a 106 th  aspect, in combination with one or more of the 101 st  through 105 th  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the device based on an address of the device on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 107 th  aspect, in combination with one or more of the 101 st  through 106 th  aspects, the processor is further configured to: wirelessly transmit, in response to the request and via a device-to-device (D2D) communication link, another allocation of the first transmission resources to the other device to receive the first transmission via the first transmission resources; transmit, over a device-to-device (D2D) communication link and to the device, a configuration for measurement of interference; and receive an interference measurement from the device according to the configuration. 
     In a 108 th  aspect, in combination with one or more of the 101 st  through 107 th  aspects, the processor is further configured to: transmit, to the device, a configuration update for transmitting from the device to the other device, wherein the configuration update is determined based on the interference measurement. 
     In a 109 th  aspect, in a wireless communications system, an apparatus in a vehicle includes a memory; and a processor coupled to the memory and configured to: receive one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receive a data packet from another device other than the central controller via the transmission resources; and wirelessly receive the data packet from a first transmission relay via the transmission resources. 
     In a 110 th  aspect, in combination with the 109 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the other device comprises wirelessly receiving the data packet via the first transmission resources; and wirelessly receiving the data packet from the first transmission relay comprises wirelessly receiving the data packet via the second transmission resources. 
     In a 111 th  aspect, in combination with one or more of the 109 th  through 110 th  aspects, the processor is further configured to: register with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 112 th  aspect, in combination with one or more of the 109 th  through 111 th  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 113 th  aspect, in combination with one or more of the 109 th  through 112 th  aspects, the processor is further configured to: power-on one or more components of the apparatus in response to receiving the allocations. 
     In a 114 th  aspect, in combination with one or more of the 109 th  through 113 th  aspects, wirelessly receiving the data packet from the first transmission relay comprises receiving the data packet from the first transmission relay and the other device simultaneously. 
     In a 115 th  aspect, in a wireless communications system, an apparatus in a vehicle includes a memory; and a processor coupled to the memory and configured to: receive one or more allocations of transmission resources from a central controller in the vehicle; wirelessly receive a data packet from a first device via a first device-to-device (D2D) communication link on the transmission resources; and wirelessly transmit the data packet to a second device via a second D2D communication link on the transmission resources. 
     In a 116 th  aspect, in combination with the 115 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; wirelessly receiving the data packet from the first device comprises wirelessly receiving the data packet via the first D2D communication link on the first transmission resources; and wirelessly transmitting the data packet to the second device comprises wirelessly transmitting the data packet via the second D2D communication link on the second transmission resources. 
     In a 117 th  aspect, in combination with one or more of the 115 th  through 116 th  aspects, wirelessly transmitting the data packet to the second device comprises transmitting simultaneously with the first device transmitting the data packet to the second device. 
     In a 118 th  aspect, in combination with one or more of the 115 th  through 117 th  aspects, the processor is further configured to: register with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 119 th  aspect, in combination with one or more of the 115 th  through 118 th  aspects, the processor is further configured to: determine a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the transmission relay is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 120 th  aspect, in combination with one or more of the 115 th  through 119 th  aspects, the processor is further configured to: receive, over a third D2D communication link, a configuration for measurement of interference; report an interference measurement according to the configuration; and receive a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the interference measurement. 
     In a 121 st  aspect, an apparatus for wireless communication includes: means for wirelessly transmitting a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle; means for monitoring for an acknowledgment (ACK) of the data packet; means for deciding whether to retransmit the data packet to the other device, based on the monitoring; and means for wirelessly transmitting the data packet to a transmission relay, wherein an intended destination of the data packet is the other device, wherein the monitoring for the ACK comprises monitoring for a first ACK from the other device and a second ACK from the transmission relay. 
     In a 122 nd  aspect, in combination with the 121 st  aspect, wirelessly transmitting the data packet directly via the first D2D communication link to the other device comprises transmitting simultaneously with a transmission relay transmitting the data packet to the other device. 
     In a 123 rd  aspect, in combination with one or more of the 121 st  through 122 nd  aspects, the apparatus includes: means for receiving an allocation of first transmission resources from a central controller in the vehicle, wherein wirelessly transmitting the data packet directly to the other device comprises transmitting the data packet via the first transmission resources; and receiving an allocation of second transmission resources from the central controller, wherein wirelessly transmitting the data packet to the transmission relay comprises transmitting the data packet via the second transmission resources. 
     In a 124 th  aspect, in combination with the 123 rd  aspect, the apparatus includes: means for transmitting a request for the allocation of first transmission resources and the allocation of second transmission resources to the central controller. 
     In a 125 th  aspect, in combination with one or more of the 123 rd  through 124 th  aspects, the apparatus includes: means for registering with the central controller using pre-configured security certificates prior to receiving the allocation of the first transmission resources or the allocation of the second transmission resources. 
     In a 126 th  aspect, in combination with one or more of the 123 rd  through 125 th  aspects, the means for receiving the allocation of the first transmission resources includes means for receiving the allocation of the first transmission resources via a second D2D communication link; and the means for receiving the allocation of the second transmission resources includes means for receiving the allocation of the second transmission resources via the second D2D communication link or a third D2D communication link. 
     In a 127 th  aspect, in combination with the 126 th  aspect, the apparatus includes: means for discovering an address of the central controller based on a broadcast via one of the first, the second, the third, or a fourth D2D communication links. 
     In a 128 th  aspect, in combination with one or more of the 121 st  through  127   th  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the apparatus is connected, wherein determining the wireless in-vehicle-network address of the apparatus comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 129 th  aspect, in combination with one more of the 121 st  through 128 th  aspects, the apparatus includes: means for receiving, over the first or a second D2D communication link, a configuration for measurement of interference; and means for reporting an interference measurement according to the configuration. 
     In a 130 th  aspect, in combination with the 129 th  aspect, the apparatus includes: means for receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the reporting the interference measurement. 
     In a 131 st  aspect, an apparatus for wireless communications in a vehicle includes: means for receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and means for wirelessly transmitting, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device, wherein the transmission resources further comprise second transmission resources for a second transmission from the device to a first transmission relay. 
     In a 132 nd  aspect, in combination with the 131 st  aspect, the allocations comprise another allocation of the first transmission resources for a second transmission from the first transmission relay to the other device. 
     In a 133 rd  aspect, in combination with one or more of the 131 st  through 132 nd  aspects, the apparatus includes: means for wirelessly transmitting one or more other allocations of transmission resources to the first transmission relay for the first transmission relay to use for a third transmission to the other device. 
     In a 134 th  aspect, in combination with one or more of the 131 st  through 133 rd  aspects, the apparatus includes: means for wirelessly transmitting one or more other allocations of transmission resources to the device for a third transmission to a second transmission relay; and wirelessly transmitting one or more other allocations of transmission resources to the second transmission relay for the second transmission relay to use for a fourth transmission to the other device. 
     In a 135 th  aspect, in combination with one or more of the 131 st  through 134 th  aspects, the apparatus includes: means for receiving a registration request from the device prior to receiving the request to transmit. 
     In a 136 th  aspect, in combination with one or more of the 131 st  through 135 th  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the device based on an address of the device on a wired in-vehicle-network bus to which the device is connected, wherein determining the wireless in-vehicle-network address of the device comprises mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 137 th  aspect, in combination with one or more of the 131 st  through 136 th  aspects, the apparatus includes: means for wirelessly transmitting, in response to the request and via a device-to-device (D2D) communication link, another allocation of the first transmission resources to the other device to receive the first transmission via the first transmission resources; means for transmitting, over a device-to-device (D2D) communication link and to the device, a configuration for measurement of interference; and means for receiving an interference measurement from the device according to the configuration. 
     In a 138 th  aspect, in combination with the 137 th  aspect, the apparatus includes: means for transmitting, to the device, a configuration update for transmitting from the device to the other device, wherein the configuration update is determined based on the interference measurement. 
     In a 139 th  aspect, an apparatus for wireless communications in a vehicle, includes: means for receiving one or more allocations of transmission resources from a central controller in the vehicle; means for wirelessly receiving a data packet from another device other than the central controller via the transmission resources; and means for wirelessly receiving the data packet from a first transmission relay via the transmission resources. 
     In a 140 th  aspect, in combination with the 139 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; the means for wirelessly receiving the data packet from the other device comprises means for wirelessly receiving the data packet via the first transmission resources; and the means for wirelessly receiving the data packet from the first transmission relay comprises wirelessly receiving the data packet via the second transmission resources. 
     In a 141 st  aspect, in combination with one or more of the 139 th  through 140 th  aspects, the apparatus includes: means for registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 142 nd  aspect, in combination with one or more of the 139 th  through 141 st  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the device based on a wired in-vehicle-network bus to which the device is connected, wherein the means for determining the wireless in-vehicle-network address of the device comprises means for mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 143 rd  aspect, in combination with one or more of the 139 th  through 142 nd  aspects, the apparatus includes: means for powering-on one or more components of the apparatus in response to receiving the allocations. 
     In a 144 th  aspect, in combination with one or more of the 139 th  through 143 rd  aspects, wirelessly receiving the data packet from the first transmission relay comprises receiving the data packet from the first transmission relay and the other device simultaneously. 
     In a 145 th  aspect, an apparatus for wireless communications in a vehicle, includes: means for receiving one or more allocations of transmission resources from a central controller in the vehicle; means for wirelessly receiving a data packet from a first device via a first device-to-device (D2D) communication link on the transmission resources; and means for wirelessly transmitting the data packet to a second device via a second D2D communication link on the transmission resources. 
     In a 146 th  aspect, in combination with the 145 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; the means for wirelessly receiving the data packet from the first device comprises means for wirelessly receiving the data packet via the first D2D communication link on the first transmission resources; and the means for wirelessly transmitting the data packet to the second device comprises means for wirelessly transmitting the data packet via the second D2D communication link on the second transmission resources. 
     In a 147 th  aspect, in combination with one or more of the 145 th  through 146 th  aspects, the means for wirelessly transmitting the data packet to the second device comprises means for transmitting simultaneously with the first device transmitting the data packet to the second device. 
     In a 148 th  aspect, in combination with one or more of the 145 th  through 147 th  aspects, the apparatus includes: means for registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 149 th  aspect, in combination with one or more of the 145 th  through 148 th  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the apparatus is connected, wherein the means for determining the wireless in-vehicle-network address of the device comprises means for mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 150 th  aspect, in combination with one or more of the 145 th  through 149 th  aspects, the apparatus includes: means for receiving, over a third D2D communication link, a configuration for measurement of interference; means for reporting an interference measurement according to the configuration; and means for receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the interference measurement. 
     In a 151 st  aspect, an apparatus for communications in a vehicle, comprising: means for wirelessly transmitting a data packet directly via a first device-to-device (D2D) communication link to another device in the vehicle; means for monitoring for an acknowledgment (ACK) of the data packet; means for deciding whether to retransmit the data packet to the other device, based on the monitoring; and means for wirelessly transmitting the data packet to a transmission relay, wherein an intended destination of the data packet is the other device, wherein the means for monitoring for the ACK comprises means for monitoring for a first ACK from the other device and a second ACK from the transmission relay. 
     In a 152 nd  aspect, in combination with the 151 st  aspect, the means for wirelessly transmitting the data packet directly via the first D2D communication link to the other device comprises means for transmitting simultaneously with a transmission relay transmitting the data packet to the other device. 
     In a 153 rd  aspect, in combination with one or more of the 151 st  through 152 nd  aspects, the apparatus includes: means for receiving an allocation of first transmission resources from a central controller in the vehicle, wherein the means for wirelessly transmitting the data packet directly to the other device comprises means for transmitting the data packet via the first transmission resources; and means for receiving an allocation of second transmission resources from the central controller, wherein the means for wirelessly transmitting the data packet to the transmission relay comprises means for transmitting the data packet via the second transmission resources. 
     In a 154 th  aspect, in combination with one or more of the 151 st  through 153 rd  aspects, the apparatus includes: means for transmitting a request for the allocation of first transmission resources and the allocation of second transmission resources to the central controller. 
     In a 155 th  aspect, in combination with one or more of the 151 st  through 154 th  aspects, the apparatus includes: means for registering with the central controller using pre-configured security certificates prior to receiving the allocation of the first transmission resources or the allocation of the second transmission resources. 
     In a 156 th  aspect, in combination with one or more of the 151 st  through 155 th  aspects, the means for receiving the allocation of the first transmission resources comprises means for receiving the allocation of the first transmission resources via a second D2D communication link; and the means for receiving the allocation of the second transmission resources comprises means for receiving the allocation of the second transmission resources via the second D2D communication link or a third D2D communication link. 
     In a 157 th  aspect, in combination with one or more of the 151 st  through 156 th  aspects, the apparatus includes: means for discovering an address of the central controller based on a broadcast via one of the first, the second, the third, or a fourth D2D communication links. 
     In a 158 th  aspect, in combination with one or more of the 151 st  through 157 th  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the apparatus is connected, wherein the means for determining the wireless in-vehicle-network address of the apparatus comprises means for mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 159 th  aspect, in combination with one or more of the 151 st  through 158 th  aspects, the apparatus includes: means for receiving, over the first or a second D2D communication link, a configuration for measurement of interference; and means for reporting an interference measurement according to the configuration. 
     In a 160 th  aspect, in combination with one or more of the 151 st  through 159 th  aspects, the apparatus includes: means for receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the interference measurement. 
     In a 161 st  aspect, an apparatus for wireless communications in a vehicle includes: means for receiving, from a device in the vehicle, a request to transmit from the device to another device in the vehicle; and means for wirelessly transmitting, in response to the request, one or more allocations of transmission resources to the device, wherein the transmission resources comprise first transmission resources for a first transmission from the device directly to the other device, wherein the transmission resources further comprise second transmission resources for a second transmission from the device to a first transmission relay. 
     In a 162 nd  aspect, in combination with the 161 st  aspect, the allocations comprise another allocation of the first transmission resources for a second transmission from the first transmission relay to the other device. 
     In a 163 rd  aspect, in combination with one or more of the 161 st  through 162 nd  aspects, the apparatus includes: means for wirelessly transmitting one or more other allocations of transmission resources to the first transmission relay for the first transmission relay to use for a third transmission to the other device. 
     In a 164 th  aspect, in combination with one or more of the 161 st  through 163 rd  aspects, the apparatus includes: means for wirelessly transmitting one or more other allocations of transmission resources to the device for a third transmission to a second transmission relay; and means for wirelessly transmitting one or more other allocations of transmission resources to the second transmission relay for the second transmission relay to use for a fourth transmission to the other device. 
     In a 165 th  aspect, in combination with one or more of the 161 st  through 164 th  aspects, the apparatus includes: means for receiving a registration request from the device prior to receiving the request to transmit. 
     In a 166 th  aspect, in combination with one or more of the 161 st  through 165 th  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the device based on an address of the device on a wired in-vehicle-network bus to which the device is connected, wherein the means for determining the wireless in-vehicle-network address of the device comprises means for mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 167 th  aspect, in combination with one or more of the 161 st  through 166 th  aspects, the apparatus includes: means for wirelessly transmitting, in response to the request and via a device-to-device (D2D) communication link, another allocation of the first transmission resources to the other device to receive the first transmission via the first transmission resources; means for transmitting, over a device-to-device (D2D) communication link and to the device, a configuration for measurement of interference; and means for receiving an interference measurement from the device according to the configuration. 
     In a 168 th  aspect, in combination with one or more of the 161 st  through 167 th  aspects, the apparatus includes: means for transmitting, to the device, a configuration update for transmitting from the device to the other device, wherein the configuration update is determined based on the interference measurement. 
     In a 169 th  aspect, an apparatus for wireless communications in a vehicle includes: means for receiving one or more allocations of transmission resources from a central controller in the vehicle; means for wirelessly receiving a data packet from another device other than the central controller via the transmission resources; and means for wirelessly receiving the data packet from a first transmission relay via the transmission resources. 
     In a 170 th  aspect, in combination with the 171 st  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; the means for wirelessly receiving the data packet from the other device comprises means for wirelessly receiving the data packet via the first transmission resources; and the means for wirelessly receiving the data packet from the first transmission relay comprises means for wirelessly receiving the data packet via the second transmission resources. 
     In a 171 st  aspect, in combination with one or more of the 169 th  through 170 th  aspects, the apparatus includes: means for registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 172 nd  aspect, in combination with one or more of the 169 th  through 171 st  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the apparatus based on a wired in-vehicle-network bus to which the apparatus is connected, wherein the means for determining the wireless in-vehicle-network address of the apparatus comprises means for mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 173 rd  aspect, in combination with one or more of the 169 th  through 172 nd  aspects, the apparatus includes: means for powering-on one or more components of the apparatus in response to receiving the allocations. 
     In a 174 th  aspect, in combination with one or more of the 169 th  through 173 rd  aspects, the means for wirelessly receiving the data packet from the first transmission relay comprises means for receiving the data packet from the first transmission relay and the other device simultaneously. 
     In a 175 th  aspect, an apparatus for wireless communications in a vehicle includes: means for receiving one or more allocations of transmission resources from a central controller in the vehicle; means for wirelessly receiving a data packet from a first device via a first device-to-device (D2D) communication link on the transmission resources; and means for wirelessly transmitting the data packet to a second device via a second D2D communication link on the transmission resources. 
     In a 176 th  aspect, in combination with the 175 th  aspect, the one or more allocations of transmission resources comprise first transmission resources and second transmission resources; the means for wirelessly receiving the data packet from the first device comprises means for wirelessly receiving the data packet via the first D2D communication link on the first transmission resources; and the means for wirelessly transmitting the data packet to the second device comprises means for wirelessly transmitting the data packet via the second D2D communication link on the second transmission resources. 
     In a 177 th  aspect, in combination with one or more of the 175 th  through 176 th  aspects, the means for wirelessly transmitting the data packet to the second device comprises means for transmitting simultaneously with the first device transmitting the data packet to the second device. 
     In a 178 th  aspect, in combination with one or more of the 175 th  through 177 th  aspects, the apparatus includes: means for registering with the central controller using pre-configured security certificates prior to receiving the one or more allocations. 
     In a 179 th  aspect, in combination with one or more of the 175 th  through 178 th  aspects, the apparatus includes: means for determining a wireless in-vehicle-network address of the transmission relay based on a wired in-vehicle-network bus to which the transmission relay is connected, wherein the means for determining the wireless in-vehicle-network address of the device comprises means for mapping the wireless in-vehicle-network address to the wired in-vehicle-network bus. 
     In a 180 th  aspect, in combination with one or more of the 175 th  through 179 th  aspects, the apparatus includes: means for receiving, over a third D2D communication link, a configuration for measurement of interference; means for reporting an interference measurement according to the configuration; and means for receiving a configuration update for the wirelessly transmitting the data packet, wherein the configuration update is determined based on the interference measurement.