Dynamic signaling of LTE-TDD configurations in the presence of D2D transmissions

A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus may be a UE. The apparatus receives a D2D resource message based on a change in an uplink-downlink subframe configuration of at least one frame. The D2D resource message enables the apparatus to determine D2D resources allocated for D2D transmissions after the change in the uplink-downlink subframe configuration. The apparatus determines a subset of the D2D resources to be used for performing D2D transmissions based on the received D2D resource message.

BACKGROUND

Field

The present disclosure relates generally to communication systems, and more particularly, to dynamic signaling of Long Term Evolution Time-Division Duplex (LTE-TDD) configurations in the presence of device-to-device (D2D) transmissions.

Background

SUMMARY

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a user equipment (UE). In one aspect, the apparatus receives a D2D resource message based on a change in an uplink-downlink subframe configuration of at least one frame. The D2D resource message enables the apparatus to determine D2D resources allocated for D2D transmissions after the change in the uplink-downlink subframe configuration. The apparatus determines a subset of the D2D resources to be used for performing D2D transmissions based on the received D2D resource message.

In another aspect, the apparatus includes means for receiving a D2D resource message based on a change in an uplink-downlink subframe configuration of at least one frame. The D2D resource message enables the apparatus to determine D2D resources allocated for D2D transmissions after the change in the uplink-downlink subframe configuration. The apparatus includes means for determining a subset of the D2D resources to be used for performing D2D transmissions based on the received D2D resource message. The apparatus may include means for receiving a configuration update message based on the change in the uplink-downlink subframe configuration of the at least one frame, in which the configuration update message indicates a set of downlink subframes and a set of uplink subframes. In an aspect, the means for determining the subset of D2D resources to be used for performing D2D transmissions may be configured to identify a downlink subframe previously configured as an uplink subframe and previously associated with resources allocated for D2D transmissions and to refrain from performing D2D transmissions on the identified downlink subframe. In another aspect, the means for determining the subset of D2D resources to be used for performing D2D transmissions may be configured to decode the D2D resource message based on an identifier associated with D2D transmissions. In another aspect, the apparatus may include means for receiving the identifier associated with D2D transmissions in a system information block. In another aspect, the D2D resource message indicates the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In another aspect, the D2D resource message is transmitted in a PDCCH. In another aspect, the D2D resource message identifies a resource on which a D2D information message will be transmitted, and the D2D information message indicates the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In another aspect, the apparatus includes means for receiving the D2D information message on the resource identified in the D2D resource message. In another aspect, the D2D resource message is received in a physical downlink control channel (PDCCH) and the D2D information message is received in a physical downlink shared channel (PDSCH). In another aspect, the D2D information message includes a bitmap that indicates one or more subframes of the at least one frame that will be converted to a downlink subframe or converted to an uplink subframe based on the change in the uplink-downlink subframe configuration.

In another aspect, the computer-readable medium is associated with a UE and stores computer executable code for wireless communication. The computer-readable medium includes code for receiving a D2D resource message based on a change in an uplink-downlink subframe configuration of at least one frame. The D2D resource message enables the UE to determine D2D resources allocated for D2D transmissions after the change in the uplink-downlink subframe configuration. The computer-readable medium includes code for determining a subset of the D2D resources to be used for performing D2D transmissions based on the received D2D resource message. In an aspect, the computer-readable medium includes code for receiving a configuration update message based on the change in the uplink-downlink subframe configuration of the at least one frame. The configuration update message indicates a set of downlink subframes and a set of uplink subframes. In another aspect, the code for determining the subset of D2D resources to be used for performing D2D transmissions may include code for identifying a downlink subframe previously configured as an uplink subframe and previously associated with resources allocated for D2D transmissions and for refraining from performing D2D transmissions on the identified downlink subframe. In another aspect, the code for determining the subset of D2D resources to be used for performing D2D transmissions may include code for decoding the D2D resource message based on an identifier associated with D2D transmissions. In another aspect, the computer-readable medium may include code for receiving the identifier associated with D2D transmissions in a system information block. In another aspect, the D2D resource message indicates the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In another aspect, the D2D resource message is transmitted in a PDCCH. In another aspect, the D2D resource message identifies a resource on which a D2D information message will be transmitted, in which the D2D information message indicates the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In another aspect, the computer-readable medium may include code for receiving the D2D information message on the resource identified in the D2D resource message. In another aspect, the D2D resource message is received in a PDCCH and the D2D information message is received in a PDSCH. In another aspect, the D2D information message includes a bitmap that indicates one or more subframes of the at least one frame that will be converted to a downlink subframe or converted to an uplink subframe based on the change in the uplink-downlink subframe configuration.

In another aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided. The apparatus may be a base station (e.g., an evolved Node B). In one aspect, the apparatus determines to reconfigure an uplink-downlink subframe configuration of at least one frame based on network traffic. The apparatus reconfigures the uplink-downlink subframe configuration based on the determination. The apparatus transmits a D2D resource message based on the reconfigured uplink-downlink subframe configuration, in which the D2D resource message enables a UE to determine D2D resources allocated for D2D transmissions based on the reconfigured uplink-downlink subframe configuration.

In another aspect, the apparatus includes means for determining to reconfigure an uplink-downlink subframe configuration of at least one frame based on network traffic. The apparatus includes means for reconfiguring the uplink-downlink subframe configuration based on the determination. The apparatus includes means for transmitting a D2D resource message based on the reconfigured uplink-downlink subframe configuration. The D2D resource message enables a UE to determine D2D resources allocated for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In an aspect, the apparatus may include means for allocating the D2D resources for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In another aspect, the reconfigured uplink-downlink subframe configuration has less uplink subframes than a previous uplink-downlink subframe configuration, and a subset of the D2D resources are allocated on a subset of uplink subframes not previously allocated for D2D transmissions in the previous uplink-downlink subframe configuration. In another aspect, the apparatus may include means for transmitting a configuration update message based on the reconfigured uplink-downlink subframe configuration of the at least one frame. The configuration update message indicates a set of downlink subframes and a set of uplink subframes. In another aspect, the apparatus may include means for transmitting an identifier associated with D2D transmissions in a system information block to enable the UE to decode the D2D resource message. In another aspect, the D2D resource message indicates the D2D resources allocated in a set of uplink subframes. In another aspect, the D2D resource message identifies a resource on which a D2D information message will be transmitted, and the D2D information message indicates the D2D resources allocated in a set of uplink subframes based on the reconfigured uplink-downlink subframe configuration. In another aspect, the apparatus may include means for transmitting the D2D information message on the resource identified in the D2D resource message. In another aspect, the D2D resource message is transmitted in a PDCCH and the D2D information message is transmitted in a PDSCH.

In another aspect, the computer-readable medium is associated with a base station and stores computer executable code for wireless communication. The computer-readable medium includes code for determining to reconfigure an uplink-downlink subframe configuration of at least one frame based on network traffic. The computer-readable medium includes code for reconfiguring the uplink-downlink subframe configuration based on the determination. The computer-readable medium includes code for transmitting a D2D resource message based on the reconfigured uplink-downlink subframe configuration, in which the D2D resource message enables a UE to determine D2D resources allocated for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In another aspect, the computer-readable medium may include code for allocating the D2D resources for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In another aspect, the reconfigured uplink-downlink subframe configuration has less uplink subframes than a previous uplink-downlink subframe configuration, and a subset of the D2D resources are allocated on a subset of uplink subframes not previously allocated for D2D transmissions in the previous uplink-downlink subframe configuration. In another aspect, the computer-readable medium may include code for transmitting a configuration update message based on the reconfigured uplink-downlink subframe configuration of the at least one frame, and the configuration update message indicates a set of downlink subframes and a set of uplink subframes. In another aspect, the computer-readable medium may include code for transmitting an identifier associated with D2D transmissions in a system information block to enable the UE to decode the D2D resource message. In another aspect, the D2D resource message indicates the D2D resources allocated in a set of uplink subframes. In another aspect, the D2D resource message identifies a resource on which a D2D information message will be transmitted, and the D2D information message indicates the D2D resources allocated in a set of uplink subframes based on the reconfigured uplink-downlink subframe configuration. In another aspect, the computer-readable medium may include code for transmitting the D2D information message on the resource identified in the D2D resource message. In another aspect, the D2D resource message is transmitted in a PDCCH and the D2D information message is transmitted in a PDSCH.

DETAILED DESCRIPTION

The E-UTRAN includes the evolved Node B (eNB)106and other eNBs108, and may include a Multicast Coordination Entity (MCE)128. The eNB106provides user and control planes protocol terminations toward the UE102. The eNB106may be connected to the other eNBs108via a backhaul (e.g., an X2 interface). The MCE128allocates time/frequency radio resources for evolved Multimedia Broadcast Multicast Service (MBMS) (eMBMS), and determines the radio configuration (e.g., a modulation and coding scheme (MCS)) for the eMBMS. The MCE128may be a separate entity or part of the eNB106. The eNB106may also be referred to as a base station, a Node B, an access point, a base transceiver station, a radio base station, a radio transceiver, a transceiver function, a basic service set (BSS), an extended service set (ESS), or some other suitable terminology. The eNB106provides an access point to the EPC110for a UE102. Examples of UEs102include a cellular phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a personal digital assistant (PDA), a satellite radio, a global positioning system, a multimedia device, a video device, a digital audio player (e.g., MP3 player), a camera, a game console, a tablet, or any other similar functioning device. The UE102may also be referred to by those skilled in the art as a mobile station, a subscriber station, a mobile unit, a subscriber unit, a wireless unit, a remote unit, a mobile device, a wireless device, a wireless communications device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a handset, a user agent, a mobile client, a client, or some other suitable terminology.

The eNB106is connected to the EPC110. The EPC110may include a Mobility Management Entity (MME)112, a Home Subscriber Server (HSS)120, other MMEs114, a Serving Gateway116, a Multimedia Broadcast Multicast Service (MBMS) Gateway124, a Broadcast Multicast Service Center (BM-SC)126, and a Packet Data Network (PDN) Gateway118. The MME112is the control node that processes the signaling between the UE102and the EPC110. Generally, the MME112provides bearer and connection management. All user IP packets are transferred through the Serving Gateway116, which itself is connected to the PDN Gateway118. The PDN Gateway118provides UE IP address allocation as well as other functions. The PDN Gateway118and the BM-SC126are connected to the IP Services122. The IP Services122may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service (PSS), and/or other IP services. The BM-SC126may provide functions for MBMS user service provisioning and delivery. The BM-SC126may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a PLMN, and may be used to schedule and deliver MBMS transmissions. The MBMS Gateway124may be used to distribute MBMS traffic to the eNBs (e.g.,106,108) belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

FIG. 2is a diagram illustrating an example of an access network200in an LTE network architecture. In this example, the access network200is divided into a number of cellular regions (cells)202. One or more lower power class eNBs208may have cellular regions210that overlap with one or more of the cells202. The lower power class eNB208may be a femto cell (e.g., home eNB (HeNB)), pico cell, micro cell, or remote radio head (RRH). The macro eNBs204are each assigned to a respective cell202and are configured to provide an access point to the EPC110for all the UEs206in the cells202. There is no centralized controller in this example of an access network200, but a centralized controller may be used in alternative configurations. The eNBs204are responsible for all radio related functions including radio bearer control, admission control, mobility control, scheduling, security, and connectivity to the serving gateway116. An eNB may support one or multiple (e.g., three) cells (also referred to as a sectors). The term “cell” can refer to the smallest coverage area of an eNB and/or an eNB subsystem serving a particular coverage area. Further, the terms “eNB,” “base station,” and “cell” may be used interchangeably herein.

Channel estimates derived by a channel estimator658from a reference signal or feedback transmitted by the eNB610may be used by the TX processor668to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor668may be provided to different antenna652via separate transmitters654TX. Each transmitter654TX may modulate an RF carrier with a respective spatial stream for transmission.

FIG. 7is a diagram of a device-to-device communications system700. The device-to-device communications system700includes a plurality of wireless devices704,706,708,710. The device-to-device communications system700may overlap with a cellular communications system, such as for example, a wireless wide area network (WWAN). Some of the wireless devices704,706,708,710may communicate together in device-to-device communication using the DL/UL WWAN spectrum, some may communicate with the base station702, and some may do both. For example, as shown inFIG. 7, the wireless devices708,710are in device-to-device communication and the wireless devices704,706are in device-to-device communication. The wireless devices704,706are also communicating with the base station702.

The exemplary methods and apparatuses discussed infra are applicable to any of a variety of wireless device-to-device communications systems, such as for example, a wireless device-to-device communication system based on FlashLinQ, WiMedia, Bluetooth, ZigBee, or Wi-Fi based on the IEEE 802.11 standard. To simplify the discussion, the exemplary methods and apparatus are discussed within the context of LTE. However, one of ordinary skill in the art would understand that the exemplary methods and apparatuses are applicable more generally to a variety of other wireless device-to-device communication systems.

In LTE, the UL-DL subframe configuration of a radio frame may be fixed from radio frame to radio frame. That is, for each radio frame, there may be a fixed number of subframes allocated for downlink communication and a fixed number of subframes allocated for uplink communication. However, traffic patterns may vary, and there may be times in which a greater number of downlink (or uplink) resources are required than what has been allocated. With Enhanced Interference Mitigation and Traffic Adaption (eIMTA), for example, resource configurations for TDD may be dynamically allocated, which allows for more flexible resource configurations. In eIMTA, a base station (e.g., an eNB) may initially utilize a first subframe configuration in a radio frame. Depending on traffic, the base station may adopt a second subframe configuration to accommodate changes in network traffic. For example, if downlink transmissions increase, the base station may transmit downlink data in a resource currently allocated for downlink communication but previously allocated for uplink communication.

FIG. 8Ais an exemplary diagram800of uplink-downlink subframe configurations in LTE-TDD with eIMTA. Referring toFIG. 8A, LTE-TDD with eIMTA may use 7 UL-DL subframe configurations for WAN communication. Each of the 7 configurations may have a set of anchor subframes and non-anchor subframes. Anchor subframes, also known as common subframes, may remain the same across different UL-DL subframe configurations. Non-anchor subframes may be changed dynamically based on traffic patterns of the network. Special non-anchor subframes may enable transition of traffic between downlink and uplink subframes. InFIG. 8A, subframes 0, 1, 2, 5 may be anchor subframes that do not change from configuration to configuration. Subframes 3, 4, 7, 8, 9 may be non-anchor subframes that may be dynamically configured based network traffic patterns (e.g., uplink subframes may be dynamically configured to be downlink subframes when traffic is downlink heavy or vice versa). Subframe 6 may be a special non-anchor subframe that may be allocated for transitions between downlink and uplink subframes (e.g., when denoted by S in UL-DL configurations 0, 1, 2, 6) or may be allocated as a downlink subframes (e.g., when denoted by D in UL-DL subframe configurations 3, 4, 5). In total,FIG. 8Adepicts 7 different UL-DL subframe configurations that may be selected based on traffic adaption.

Traffic adaptation via dynamic TDD UL-DL reconfiguration has the potential of improving packet throughput and energy savings, provided that new inter-cell interference can be managed appropriately. In an aspect, a default configuration in LTE-TDD may be chosen to be uplink heavy (e.g., UL-DL subframe configurations 0, 1). When the cell becomes downlink heavy, the more downlink heavy configurations (e.g., UL-DL subframe configurations 4, 5) may be selected. Different configurations may be chosen by converting certain non-anchor uplink subframes into downlink subframes. For example, subframes 7, 8 in UL-DL configuration 1 are converted into downlink subframes in UL-DL configuration 4. By contrast, if a downlink heavy configuration is used and more uplink resources are needed, a more uplink heavy configuration may be selected.

In networks that enable D2D transmissions (e.g., D2D transmission may include D2D communications, D2D discovery, and/or D2D synchronization), semi-statically configured D2D subframes (e.g., uplink subframes with resources reserved for D2D communications) occur periodically. Due to traffic adaptation (or UL-DL subframe reconfiguration), the assigned D2D subframes may be converted from uplink into downlink subframes based on downlink traffic demand (or converted from downlink into uplink subframes based on uplink traffic demand). When uplink subframes are converted into downlink subframes, D2D transmission on subframes previously allocated for uplink may introduce interference to the eIMTA UEs that are receiving downlink data from an eNB as illustrated inFIG. 8B.

FIG. 8Billustrates potential interference scenarios in an eIMTA LTE-TDD network850with D2D and WAN co-existence. Referring toFIG. 8B, the eIMTA LTE-TDD network850includes a base station852, a first UE854, a second UE856, and a third UE858. The first UE854and the second UE856may have a D2D communication link and send or receive D2D transmissions860(e.g., D2D communications, D2D discovery messages, D2D synchronization messages) using uplink subframes. The base station852may be using UL-DL subframe configuration 0, and the first and second UEs854,856may be using subframe 4, for example, for D2D transmissions. Subsequently, the third UE858may request a downlink transmission, which requires more downlink resources than what is offered by the UL-DL subframe configuration 0. The base station852may reconfigure the UL-DL configuration from configuration 0 to configuration 1, for example, after determining that additional downlink resources are needed. Having reconfigured the UL-DL subframe configuration, the base station852may send WAN transmissions862to the third UE858using resources in subframe 4, which was previously allocated for D2D transmissions. As shown in the dotted lines, the WAN transmissions862on the downlink from the base station852to the third UE858may cause interference to the first UE854, which is receiving D2D transmissions860from the second UE856on subframe 4. Similarly, as shown again by the dotted lines, the D2D transmissions860may introduce interference to the third UE858(or other eIMTA UEs that are receiving downlink data from the eNB over resources in subframe 4). As such, a need exists to improve the co-existence of D2D transmissions in the presence of an eIMTA LTE-TDD network. AlthoughFIG. 8Billustrates three UEs, any number of UEs may be in the cell.

FIG. 9illustrates a method of dynamically signaling a change in LTE-TDD configurations in the presence of D2D transmissions in a wireless network900. The wireless network900may include a base station902(e.g., an eNB), a first UE904, a second UE906, and a third UE908(or any other number of eNBs and/or UEs). In an example, the base station902may initially use UL-DL subframe configuration 0 for WAN (and D2D) transmissions. The first and second UEs904,906may be allocated D2D resources on subframes 3, 4 for D2D transmissions. As such, the first and second UEs904,906may transmit and/or receive D2D transmissions910on D2D resources allocated in subframes 3, 4. The third UE908and/or other UEs (not pictured) may request downlink WAN transmissions912from the base station902. For example, the third UE908may request and initiate a video stream, which may require more downlink resources. Because UL-DL subframe configuration 0 has 2 subframes (e.g., subframes 0, 5) allocated for downlink communication, the base station902may determine that the current UL-DL subframe configuration does not support the anticipated downlink traffic. To adapt to the heavier downlink traffic, the base station902may reconfigure/change the UL-DL configuration and select UL-DL configuration 1, for example. In UL-DL configuration 1, subframes 4, 9 have been converted from uplink to downlink use. Upon changing the UL-DL subframe configuration for at least one radio frame, the base station902may transmit a configuration update message914to all UEs being served by the base station902. In an aspect, the configuration update message914may be broadcasted. In another aspect, the configuration update message914may indicate a new UL-DL subframe configuration selected by the base station902and be associated with one or more radio frames. In another aspect, the configuration update message914may include an indicator (e.g., a configuration indicator) having two or more bits to indicate the subframe configuration (e.g., the two or more bits may be used to indicate a number between 0-6). The indicator may indicate a set of downlink subframes (e.g., subframes 0, 5 in configuration 0) and a set of uplink subframes (e.g., subframes 2, 3, 4, 7, 8, 9 in configuration 0). In an aspect, wireless devices within the wireless network900may be preconfigured with information that enables the wireless devices to associate various indicator values with different UL-DL subframe configurations. The first, second, and third UEs904,906,908may receive the configuration update message914and determine which subframes are allocated for uplink versus downlink transmission.

As previously discussed, in the example when UL-DL configuration 0 has been selected, the base station902may have allocated subframes 3, 4 to the first and second UEs904,906for D2D transmissions. After the change in UL-DL configuration, subframe 4 is now allocated for downlink transmission. If the first UE904or the second UE906continues to perform D2D transmissions on subframe 4 while the base station902and the third UE908are also using subframe 4 for downlink communications, then the first and second UEs904,906may cause interference to the base station902and/or the third UE908. In an aspect, the configuration update message914may not indicate whether any new resources have been allocated for D2D transmissions. The configuration update message914may not indicate that resources previously allocated for D2D transmissions should no longer be used for D2D transmissions. As such, the first and second UEs904,906may continue to use subframe 4 for D2D transmissions, which could lead to unintended interference.

To avoid such interference, the first and second UEs904,906may monitor downlink transmissions for signaling (e.g., L1 signaling) from the base station902. The signaling may indicate, before the occurrence of a resource, whether the resource previously allocated for D2D transmissions will be to be used for downlink transmission, and therefore, should no longer be used for D2D transmissions. The first and second UEs904,906may perform such monitoring while in an RRC_IDLE and/or an RRC_CONNECTED state.

In one configuration, based on a decision to reconfigure the UL-DL configuration due to traffic patterns, the base station902may allocate different/new resources for D2D transmissions based on the reconfigured UL-DL configuration. For example, the base station902may identify the uplink subframes under the reconfigured UL-DL configuration and reserve a subset of resources (e.g., time-frequency resources) within the uplink subframes for scheduling assignment and for data transmission in D2D transmissions. In an aspect, the base station902may transmit (or broadcast) signaling that indicates newly allocated D2D resources in a D2D resource message916. The D2D resource message916may indicate any resources (e.g., time-frequency resources associated with one or more subframes) newly allocated for D2D transmissions in one or more uplink subframes according to the reconfigured UL-DL subframe configuration. The resources allocated for D2D transmissions may be for one or more radio frames. In another aspect, the number of radio frames for which the resources are allocated may be indicated in the D2D resource message916. In another aspect, the D2D resource message916may also identify any subframes that were previously allocated for uplink transmission in the previous UL-DL configuration that will be converted to downlink subframes. For example, the D2D resource message916may include a bitmap that indicates the uplink subframes associated with D2D transmissions that will be converted into downlink subframes for future radio frames. In an aspect, the base station902may transmit the D2D resource message916over a physical downlink control channel (PDCCH). In another aspect, the D2D resource message916may include a cyclic redundancy check (CRC) appended to the D2D resource message916. The CRC may be scrambled with an identifier such as a radio network temporary identifier (RNTI). The RNTI may be a Broadcast D2D-RNTI, which may be a common RNTI known to all UEs interested in D2D transmissions. In an aspect, the identifier may be broadcast by the base station902in a system information block (SIB) (e.g., the base station902may send the Broadcast D2D-RNTI in a SIB1). By scrambling the CRC of the D2D resource message916with the identifier, UEs not interested in D2D transmissions may ignore the D2D resource message916, and UEs interested in D2D transmissions (e.g., the first UE904and the second UE906) may decode the D2D resource message916based on the identifier. Upon receiving the D2D resource message916, the first and second UEs904,906may decode the D2D resource message916using the identifier. After decoding the D2D resource message916, the first and second UEs904,906may determine that subframe 4, previously an uplink subframe containing resources for D2D transmissions, is now a downlink subframe. The first and second UEs904,906may refrain from performing D2D transmissions on subframe 4 (and on any other subframes converted from uplink to downlink subframes). That is, in this example, the first and second UEs904,906may not transmit or receive D2D communications on subframe 4. The first and second UEs904,906may determine, based on the received D2D resource message916, the resources allocated for D2D transmissions within one or more uplink subframes in the reconfigured UL-DL subframe configuration. In this configuration, an offset between when the D2D resource message916(or other L1 signaling) is sent and when the D2D resources occur may be fixed (e.g., predetermined) or configurable based on network signaling.

In another configuration, based on a decision to reconfigure the UL-DL subframe configuration, the base station902may have more detailed information regarding D2D transmissions to send to the first and second UEs904,906. In this configuration, the D2D resource message916may not be able to transmit all of the detailed information in the PDCCH. Instead, the base station902may transmit the D2D resource message916to indicate a resource (e.g., a set of time-frequency resources) on which a D2D information message918will be transmitted. Similar to the D2D resource message916discussed in the previous configuration, the D2D information message918may indicate resources for D2D transmissions in a reconfigured UL-DL subframe configuration. Unlike in the previous configuration, however, the D2D information message918may be used to indicate resources allocated for D2D transmissions rather than the D2D resource message916. In this configuration, the D2D resource message916may enable the first and second UEs904,906to locate the D2D information message918. The D2D information message918may indicate the resources for D2D transmissions in a greater number of radio frames than could be indicated in the D2D resource message916in the previously discussed configuration. The D2D information message918may indicate that the D2D resources have been allocated for an indicated number of radio frames. In other words, the D2D information message918may carry more information/data than D2D resource message916. The D2D information message918may indicate which uplink subframes have been converted to downlink subframes. The D2D information message918may also include parameters associated with one or more D2D communication links. Such parameters may include a suggested transmission power for D2D transmissions, a suggested modulation and coding scheme (MCS) for D2D transmissions, and/or a bitmap that indicates the uplink subframes associated with D2D transmissions that will be converted into downlink subframes for future radio frames. In an aspect, a bitmap carried by the D2D information message918may be larger than a bitmap carried by the D2D resource message916. In another aspect, the base station902may transmit the D2D resource message916over a PDCCH and transmit the D2D information message918over a PDSCH. In this configuration, an offset between when the D2D resource message918(or other L1 signaling) is sent and when the D2D resources occur may be fixed or configurable.

Having determined the allocated D2D resources based on the received D2D resource message916and/or the received D2D information message918, the first and second UEs904,906may determine a subset of the allocated D2D resources to be used for performing D2D transmissions. In an aspect, if the first UE904has a large amount of data to send, then the first UE904may select a larger subset of the allocated D2D resources to use for the D2D transmissions910. In another aspect, if the first UE904has less data to send, then the first UE904may select a smaller subset of the allocated D2D resources to use for the D2D transmissions910. In yet another aspect, resource selection may also be based on priority of the data to be transmitted. If the first UE904has high priority data for transmission, then the first UE904may select a larger subset of the allocated D2D resources, but if the first UE904has low priority data for transmission, then the first UE904may select a smaller subset of the allocated D2D resources and leave the remaining resources for other UEs. Similarly, if other UEs in the wireless network900are engaging in D2D transmissions (e.g., D2D communications), the first UE904may select the subset of D2D resources based on an energy detection level on the D2D resources. The first UE904may select a subset of resources with a comparatively lower energy detection level to minimize interference with other D2D transmissions. In another aspect, the D2D resource message916or the D2D information message918may indicate which resources are allocated to which UEs for D2D transmissions based on a UE identifier (e.g., a MAC address). In this aspect, the first UE904may determine the subset of resources to use for D2D transmissions based on which resources are associated with the identifier of the first UE904. In another aspect, the subset of allocated D2D resources selected by the first UE904may include all the resources allocated for D2D transmissions.

FIG. 10is a flowchart1000of a method of wireless communication. The method may be performed by a UE (e.g., the first UE904, the second UE906, the apparatus1202/1202′, infra). At block1002, the UE may receive a configuration update message based on a change in an uplink-downlink subframe configuration of at least one frame. The configuration update message may indicate a set of downlink subframes and a set of uplink subframes. For example, referring toFIG. 9, the first UE904may receive the configuration update message914based on a change in the UL-DL subframe configuration (e.g., from configuration 0 to configuration 1) of at least one frame. The configuration update message914may indicate a set of downlink subframes (0, 4, 5, 9) and a set of uplink subframes (2, 3, 7, 8).

At block1004, the UE may receive an identifier associated with D2D transmissions in a system information block. For example, referring toFIG. 9, the first UE904may receive a Broadcast D2D-RNTI associated with D2D transmissions from the base station902in a SIB1.

At block1006, the UE may receive a D2D resource message based on the change in the uplink-downlink subframe configuration of the at least one frame. The D2D resource message may enable the UE to determine D2D resources allocated for D2D transmissions after the change in the uplink-downlink subframe configuration. In one configuration, the D2D resource message may indicate the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In this configuration, the D2D resource message may be transmitted in a PDCCH. In another configuration, the D2D resource message may identify resources on which a D2D information message will be transmitted, and the D2D information message may indicate the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. For example, referring toFIG. 9, the first UE904may receive the D2D resource message916based on the change in the UL-DL subframe configuration of at least one radio frame. The D2D resource message916may enable the first UE904to determine D2D resources allocated for D2D transmissions after the change in the UL-DL subframe configuration from configuration 0 to configuration 1. In one aspect, the D2D resource message916may be transmitted on the PDCCH and may indicate the D2D resources, in a set of uplink subframes (e.g., subframes 3, 7 of configuration 1), allocated for D2D transmissions. In another aspect, the D2D resource message916may identify a resource on which the D2D information message918will be transmitted. In this aspect, the D2D information message918may indicate the D2D resources, in a set of uplink subframes (e.g., subframes 3, 7 of configuration 1), allocated for D2D transmissions.

At block1008, the UE may receive the D2D information message on a resource identified in the D2D resource message. In an aspect, the D2D resource message may be received in a PDCCH and the D2D information message may be received in a PDSCH. In another aspect, the D2D information message may include a bitmap that indicates one or more subframes of the at least one frame that will be converted to a downlink subframe or converted to an uplink subframe based on the change in the uplink-downlink subframe configuration. For example, referring toFIG. 9, the first UE904may receive the D2D information message918on the resource identified in the D2D resource message916. In this example, the D2D resource message916may be received in the PDCCH and the D2D information message918may be received in the PDSCH. In an aspect, the D2D information message918may include a bitmap that indicates that subframes 4, 9 of the next 12 radio frames will be converted to a downlink subframe based on the change in the UL-DL subframe configuration.

Finally, at block1010, the UE may determine a subset of the D2D resources to be used for performing D2D transmissions based on the received D2D resource message. In an aspect, the UE may determine the subset of the D2D resources to be used for performing D2D transmissions by identifying a downlink subframe previously configured as an uplink subframe and previously associated with resources allocated for D2D transmissions and refrain from performing D2D transmissions on the identified downlink subframe. In another aspect, the UE may determine the subset of D2D resources to be used for performing D2D transmissions by decoding the D2D resources message based on an identifier associated with D2D transmissions. For example, referring toFIG. 9, the first UE904may determine a subset of the D2D resources to be used for performing D2D transmissions with the second UE906based on the received D2D resource message916. The first UE904may use the Broadcast D2D-RNTI to decode the D2D resource message916. In an aspect, the D2D resource message916may indicate the D2D resources for D2D transmissions. In another aspect, the D2D resource message916may provide the resource(s) for receiving the D2D information message918, and the first UE904may receive the D2D information message918on the resource(s) indicated by the D2D resource message916. In this aspect, the first UE904may decode the D2D information message918and determine the resources allocated for D2D transmissions. Having determined the D2D resources indicated in either the D2D resource message916or the D2D information message918, the first UE904may use a subset of the D2D resources allocated for D2D transmissions. In an aspect, the subset may include all of the D2D resources allocated for D2D transmissions. In another aspect, the subset may include a portion of the D2D resources allocated for D2D transmissions. If the subset includes the portion of the D2D resources, then the portion may be selected based on an energy detection level of the available D2D resources, a priority of transmission of the first UE904, and/or specific resource assignments to the first UE904indicated in the D2D resource message916or the D2D information message918.

FIG. 11is a flowchart1100of a method of wireless communication. The method may be performed by a base station (e.g., the base station902, the apparatus1402/1402′, infra). At1102, the base station may determine to reconfigure an uplink-downlink subframe configuration of at least one frame based on network traffic. For example, referring toFIG. 9, the base station902may determine to reconfigure an UL-DL subframe configuration of at least one radio frame based on the traffic in the wireless network900. In this example, the base station902may receive a request from the third UE908requesting additional downlink transmissions (e.g., to support a video streaming service). The base station902may be using UL-DL subframe configuration 0 and may determine that the current configuration does not have enough downlink subframes to support the throughput required by the third UE908. Accordingly, the base station902may determine that additional downlink subframes are required. In an aspect, the base station902may determine the amount of downlink subframes needed to support the traffic throughput. For example, the base station902may determine that 2 more downlink subframes are needed.

At block1104, the base station may reconfigure the uplink-downlink subframe configuration based on the determination. For example, referring toFIG. 9, the base station902may reconfigure the UL-DL subframe configuration based on the determination that reconfiguration is needed. In an aspect, the base station902may identify one or more UL-DL subframe configurations that have more downlink subframes than a current UL-DL subframe configuration and switch to anyone of the identified one or more UL-DL subframe configurations. In another aspect, the base station902may determine the number of additional downlink subframes required to support the additional network downlink (e.g., 2 more downlink subframes), identify one or more UL-DL subframe configurations that satisfy the requirement, and switch to the one or more UL-DL subframe configuration (e.g., the base station902may reconfigure the UL-DL subframe configuration from configuration 0 to configuration 1).

At block1106, the base station may transmit a configuration update message based on the reconfigured uplink-downlink subframe configuration of the at least one frame. The configuration update message may indicate a set of downlink subframes and a set of uplink subframes. For example, referring toFIG. 9, the base station902may transmit the configuration update message914based on the reconfigured UL-DL subframe configuration of the at least one radio frame. The configuration update message914may indicate a set of downlink subframes (e.g., subframes 0, 4, 5, 9) and a set of uplink subframes (e.g., 2, 3, 7, 8). In an aspect, the configuration update message914may indicate the set of downlink subframes and the set of uplink subframes by a bit indicator (e.g., 2-bit indicator) that corresponds to a configuration number (configuration 0-6).

At block1108, the base station may allocate D2D resources for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In an aspect, the reconfigured uplink-downlink subframe configuration may have less uplink subframes than a previous uplink-downlink subframe configuration, and a subset of the D2D resources are allocated on a subset of uplink subframes not previously allocated for D2D transmissions in the previous uplink-downlink subframe configuration. For example, referring toFIG. 9, the base station902may allocate D2D resources for D2D transmissions based on the reconfiguration UL-DL subframe configuration. The base station902may determine that configuration 1 is the new UL-DL subframe configuration. Configuration 1 may have less uplink subframes (e.g., 4 uplink subframes) than configuration 0 (e.g., 6 uplink subframes). The base station902may determine that, in configuration 1, subframes 2, 3, 7, 8 are uplink subframes. The base station902may allocate D2D resources within the subframes 3, 7 of configuration 1 (versus subframes 3, 4 of configuration 0). In aspect, the base station902may allocate specific D2D resources to specific UEs (e.g., the first UE904and the second UE906). In this aspect, the allocation may be based on a distance between the base station902and the UE. In another aspect, if only a part of the D2D resources previously available for D2D transmissions continue to be available under the reconfigured UL-DL subframe configuration, then some of the D2D resources can be reassigned. For example, if scheduling assignment resources are used for downlink, then there may not be much value in having data resources associated with the same scheduling assignment resources. As such, the base station902may convert/reallocate some of the data resources into scheduling assignment resources.

At block1110, the base station may transmit an identifier associated with D2D transmissions in a system information block to enable a UE to decode a D2D resource message. For example, the base station902may transmit a Broadcast D2D-RNTI associated with D2D transmissions in a SIB1 to enable the first UE904to decode the D2D resource message916.

At block1112, the base station may transmit the D2D resource message based on the reconfigured uplink-downlink subframe configuration. The D2D resource message may enable the UE to determine the D2D resources allocated for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In an aspect, the D2D resource message may indicate the D2D resources allocated in a set of uplink subframes. In another aspect, the D2D resource message may identify a resource on which a D2D information message will be transmitted. The D2D information message may indicate the D2D resources allocated in a set of uplink subframes based on the reconfigured uplink-downlink subframe configuration. For example, referring toFIG. 9, the base station902may transmit the D2D resource message916based on the reconfigured UL-DL subframe configuration. The D2D resource message916enables the first UE904to determine the D2D resources allocated for D2D transmissions based on the reconfigured UL-DL subframe configuration. In aspect, the D2D resource message916may indicate the D2D resources allocated in uplink subframes 3 and 7. In another aspect, the D2D resource message916identifies a resource on which the D2D information message918will be transmitted (e.g., one or more symbols and associated subcarriers), and the D2D information message will indicate the D2D resources allocated in the uplink subframes 3, 7 based on configuration 1.

Finally, at block1114, the base station may transmit the D2D information message on the resource identified in the D2D resource message. For example, referring toFIG. 9, the base station902may transmit the D2D information message918on the resource identified in the D2D resource message916. The D2D resource message916may be transmitted on the PDCCH, and the D2D information message918may be transmitted on the PDSCH.

FIG. 12is a conceptual data flow diagram1200illustrating the data flow between different modules/means/components in an exemplary apparatus1202. The apparatus may be a UE. The apparatus includes a reception module1204, a D2D transmission module1206, and a transmission module1208. The reception module1204may be configured to receive a D2D resource message from a base station1250based on a change in an uplink-downlink subframe configuration of at least one frame. The D2D resource message may enable the apparatus to determine D2D resources allocated for D2D transmissions after the change in the uplink-downlink subframe configuration. The D2D transmission module1206may be configured to determine a subset of the D2D resources to be used for performing D2D transmissions with a UE1260based on the received D2D resource message. In one configuration, the reception module1204may be configured to receive a configuration update message from the base station1250based on the change in the uplink-downlink subframe configuration of the at least one frame. The configuration update message may indicate a set of downlink subframes and a set of uplink subframes. In another configuration, the D2D transmission module1206may be configured to determine the subset of D2D resources to be used for performing D2D transmissions by identifying a downlink subframe previously configured as an uplink subframe and previously associated with resources allocated for D2D transmission and by refraining from performing D2D transmission on the identified downlink subframe. In another configuration, the D2D transmission module1206may be configured to determine the subset of D2D resources to be used for performing D2D transmissions by decoding the D2D resource message based on an identifier associated with D2D transmissions. In this configuration, the reception module1204may be configured to receive the identifier associated with D2D transmissions in a system information block. In an aspect, the D2D resource message may indicate the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In another aspect, the D2D resource message may be transmitted in a PDCCH. In another configuration, the D2D resource message may identify resources on which a D2D information message will be transmitted, and the D2D information message may indicate the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In this configuration, the reception module1204may be configured to receive the D2D information message on the resource identified in the D2D resource message. In an aspect, the D2D resource message may be received in a PDCCH and the D2D information message may be received in a PDSCH. In another aspect, the D2D information message may include a bitmap that indicates one or more subframes of the at least one frame that will be converted to a downlink subframe or converted to an uplink subframe based on the change in the uplink-downlink subframe configuration.

FIG. 13is a diagram1300illustrating an example of a hardware implementation for an apparatus1202′ employing a processing system1314. The processing system1314may be implemented with a bus architecture, represented generally by the bus1324. The bus1324may include any number of interconnecting buses and bridges depending on the specific application of the processing system1314and the overall design constraints. The bus1324links together various circuits including one or more processors and/or hardware modules, represented by the processor1304, the modules1204,1206,1208, and the computer-readable medium/memory1306. The bus1324may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system1314may be coupled to a transceiver1310. The transceiver1310is coupled to one or more antennas1320. The transceiver1310provides a means for communicating with various other apparatus over a transmission medium. The transceiver1310receives a signal from the one or more antennas1320, extracts information from the received signal, and provides the extracted information to the processing system1314, specifically the reception module1204. In addition, the transceiver1310receives information from the processing system1314, specifically the transmission module1208, and based on the received information, generates a signal to be applied to the one or more antennas1320. The processing system1314includes a processor1304coupled to a computer-readable medium/memory1306. The processor1304is responsible for general processing, including the execution of software stored on the computer-readable medium/memory1306. The software, when executed by the processor1304, causes the processing system1314to perform the various functions described supra for any particular apparatus. The computer-readable medium/memory1306may also be used for storing data that is manipulated by the processor1304when executing software. The processing system further includes at least one of the modules1204,1206,1208. The modules may be software modules running in the processor1304, resident/stored in the computer readable medium/memory1306, one or more hardware modules coupled to the processor1304, or some combination thereof. The processing system1314may be a component of the UE650and may include the memory660and/or at least one of the TX processor668, the RX processor656, and the controller/processor659.

In one configuration, the apparatus1202/1202′ for wireless communication includes means for receiving a D2D resource message based on a change in an uplink-downlink subframe configuration of at least one frame. The D2D resource message may enable the apparatus to determine D2D resources allocated for D2D transmissions after the change in the uplink-downlink subframe configuration. The apparatus includes means for determining a subset of the D2D resources to be used for performing D2D transmissions based on the received D2D resource message. The apparatus may include means for receiving a configuration update message based on the change in the uplink-downlink subframe configuration of the at least one frame. The configuration update message may indicate a set of downlink subframes and a set of uplink subframes. In an aspect, the means for determining the subset of D2D resources to be used for performing D2D transmissions may be configured to identify a downlink subframe previously configured as an uplink subframe and previously associated with resources allocated for D2D transmission and to refrain from performing D2D transmission on the identified downlink subframe. In an aspect, the means for determining the subset of D2D resources to be used for performing D2D transmissions may be configured to decode the D2D resource message based on an identifier associated with D2D transmissions. In this aspect, the apparatus may include means for receiving the identifier associated with D2D transmissions in a system information block. In another aspect, the D2D resource message may indicate the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In another aspect, the D2D resource message may be transmitted in a PDCCH. In another aspect, the D2D resource message may identify resources on which a D2D information message will be transmitted. The D2D information message may indicate the D2D resources, in a set of uplink subframes, allocated for D2D transmissions. In another aspect, the apparatus may include means for receiving the D2D information message on the resource identified in the D2D resource message. In another aspect, the D2D resource message may be received in a PDCCH and the D2D information message may be received in a PDSCH. In another aspect, the D2D information message may include a bitmap that indicates one or more subframes of the at least one frame that will be converted to a downlink subframe or converted to an uplink subframe based on the change in the uplink-downlink subframe configuration. The aforementioned means may be one or more of the aforementioned modules of the apparatus1202and/or the processing system1314of the apparatus1202′ configured to perform the functions recited by the aforementioned means. As described supra, the processing system1314may include the TX Processor668, the RX Processor656, and the controller/processor659. As such, in one configuration, the aforementioned means may be the TX Processor668, the RX Processor656, and the controller/processor659configured to perform the functions recited by the aforementioned means.

FIG. 14is a conceptual data flow diagram1400illustrating the data flow between different modules/means/components in an exemplary apparatus1402. The apparatus may be a base station (e.g., an eNB). The apparatus includes a reception module1404, a subframe configuration module1406, a D2D resource allocation module1408, and a transmission module1410. The subframe configuration module1406may be configured to determine to reconfigure an uplink-downlink subframe configuration of at least one frame based on network traffic. The subframe configuration module1406may be configured to reconfigure the uplink-downlink subframe configuration based on the determination. The transmission module1410may be configured to transmit a D2D resource message based on the reconfigured uplink-downlink subframe configuration. The D2D resource message may enable a UE1450to determine D2D resources allocated for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. The D2D resource allocation module1408may be configured to allocate the D2D resources for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In an aspect, the reconfigured uplink-downlink subframe configuration may have less uplink subframes than a previous uplink-downlink subframe configuration, and a subset of the D2D resources may be allocated on a subset of uplink subframes not previously allocated for D2D transmissions in the previous uplink-downlink subframe configuration. In one configuration, the transmission module1410may be configured to transmit a configuration update message based on the reconfigured uplink-downlink subframe configuration of the at least one frame. The configuration update message may indicate a set of downlink subframes and a set of uplink subframes. In another configuration, the transmission module1410may be configured to transmit an identifier associated with D2D transmissions in a system information block to enable the UE1450to decode the D2D resource message. In an aspect, the D2D resource message may indicate the D2D resources allocated in a set of uplink subframes. In another aspect, the D2D resource message may identify resources on which a D2D information message will be transmitted. The D2D information message may indicate the D2D resources allocated in a set of uplink subframes based on the reconfigured uplink-downlink subframe configuration. In another configuration, the transmission module1410may be configured to transmit the D2D information message on the resource identified in the D2D resource message. In this configuration, the D2D resource message may be transmitted in a PDCCH and the D2D information message may be transmitted in a PDSCH.

FIG. 15is a diagram1500illustrating an example of a hardware implementation for an apparatus1402′ employing a processing system1514. The processing system1514may be implemented with a bus architecture, represented generally by the bus1524. The bus1524may include any number of interconnecting buses and bridges depending on the specific application of the processing system1514and the overall design constraints. The bus1524links together various circuits including one or more processors and/or hardware modules, represented by the processor1504, the modules1404,1406,1408,1410, and the computer-readable medium/memory1506. The bus1524may also link various other circuits such as timing sources, peripherals, voltage regulators, and power management circuits, which are well known in the art, and therefore, will not be described any further.

The processing system1514may be coupled to a transceiver1510. The transceiver1510is coupled to one or more antennas1520. The transceiver1510provides a means for communicating with various other apparatus over a transmission medium. The transceiver1510receives a signal from the one or more antennas1520, extracts information from the received signal, and provides the extracted information to the processing system1514, specifically the reception module1404. In addition, the transceiver1510receives information from the processing system1514, specifically the transmission module1410, and based on the received information, generates a signal to be applied to the one or more antennas1520. The processing system1514includes a processor1504coupled to a computer-readable medium/memory1506. The processor1504is responsible for general processing, including the execution of software stored on the computer-readable medium/memory1506. The software, when executed by the processor1504, causes the processing system1514to perform the various functions described supra for any particular apparatus. The computer-readable medium/memory1506may also be used for storing data that is manipulated by the processor1504when executing software. The processing system further includes at least one of the modules1404,1406,1408,1410. The modules may be software modules running in the processor1504, resident/stored in the computer readable medium/memory1506, one or more hardware modules coupled to the processor1504, or some combination thereof. The processing system1514may be a component of the eNB610and may include the memory676and/or at least one of the TX processor616, the RX processor670, and the controller/processor675.

In one configuration, the apparatus1402/1402′ for wireless communication includes means for determining to reconfigure an uplink-downlink subframe configuration of at least one frame based on network traffic. The apparatus includes means for reconfiguring the uplink-downlink subframe configuration based on the determination. The apparatus includes means for transmitting a D2D resource message based on the reconfigured uplink-downlink subframe configuration. The D2D resource message may enable a UE to determine D2D resources allocated for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. The apparatus may include means for allocating the D2D resources for D2D transmissions based on the reconfigured uplink-downlink subframe configuration. In an aspect, the reconfigured uplink-downlink subframe configuration may have less uplink subframes than a previous uplink-downlink subframe configuration, and a subset of the D2D resources may be allocated on a subset of uplink subframes not previously allocated for D2D transmissions in the previous uplink-downlink subframe configuration. In another aspect, the apparatus may include means for transmitting a configuration update message based on the reconfigured uplink-downlink subframe configuration of the at least one frame. The configuration update message may indicate a set of downlink subframes and a set of uplink subframes. In another aspect, the apparatus may include means for transmitting an identifier associated with D2D transmissions in a system information block to enable the UE to decode the D2D resource message. In another aspect, the D2D resource message may indicate the D2D resources allocated in a set of uplink subframes. In another aspect, the D2D resource message may identify resources on which a D2D information message will be transmitted. In this aspect, the D2D information message may indicate the D2D resources allocated in a set of uplink subframes based on the reconfigured uplink-downlink subframe configuration. In another aspect, the apparatus may include means for transmitting the D2D information message on the resource identified in the D2D resource message. In another aspect, the D2D resource message may be transmitted in a PDCCH and the D2D information message may be transmitted in a PDSCH. The aforementioned means may be one or more of the aforementioned modules of the apparatus1402and/or the processing system1514of the apparatus1402′ configured to perform the functions recited by the aforementioned means. As described supra, the processing system1514may include the TX Processor616, the RX Processor670, and the controller/processor675. As such, in one configuration, the aforementioned means may be the TX Processor616, the RX Processor670, and the controller/processor675configured to perform the functions recited by the aforementioned means.