Patent ID: 12238680

DETAILED DESCRIPTION

The detailed description set forth below in connection with the appended drawings is intended as a description of various configurations and is not intended to represent the only configurations in which the concepts described herein may be practiced. The detailed description includes specific details for the purpose of providing a thorough understanding of various concepts. However, it will be apparent to those skilled in the art that these concepts may be practiced without these specific details. In some instances, well known structures and components are shown in block diagram form in order to avoid obscuring such concepts.

The present aspects generally relate to sidelink relay communications, which includes a relay user equipment (UE) relaying communications from a base station over a sidelink to a UE, or from UE to the base station via the relay UE. Device-to-device (D2D) connectivity may be supported in some wireless communication systems (e.g., Long Term Evolution (LTE) and/or New Radio (NR)). In some aspects, application of D2D may include vehicle-to-everything (V2X), sensor networks, public-safety-related communication services with limited infrastructure availability. Further, in some wireless communication systems (e.g., NR), multi-link communication may be supported for improved diversity and throughput. For example, in millimeter wave (mmW) systems, multi-link communication may be altered using multiple transmission and/or reception beams and multiple antenna panels (e.g., sub-arrays).

In an example, one or both of a destination UE and the relay UE may further include a direct access link to the base station. Specifically, the access link may be a communication link between a UE and a base station (e.g., gNB), also referred to as a Uu interface (DL/UL) in LTE or NR. Further, a sidelink may be a communication link between UEs, also referred to as a ProSe 5 (PC5) interface in LTE or NR. In some aspects, from a UE perspective, topologies of multi-link communications and sidelink relaying may be similar. However, unlike some other destination UEs that may be able to establish multi-link communication with one or more base stations over two or more communication links, the destination UE may include a single antenna panel, whereby multi-link and/or multi transmit/reception points (TRPs) communication is not supported. In such a case, sidelink relaying may be used to implement a virtual multi-link communication. That is, a relay node may serve as an additional virtual antenna panel for the destination UE. Such multi-link communications are desirable, for example, to increase diversity and/or to increase throughput.

Specifically, present disclosure relates to enhancements to the sidelink relay communication scenario, and in particular, to sidelink-assisted multi-link communication. The present disclosure provides apparatus and methods in which the relay UE may receive, from a base station, a grant for one or both of one or more access link resources or one or more sidelink resources. The relay UE may further receive data from at least one of the base station on an access link using the one or more access link resources, or the sidelink-assisted multi-link UE on a sidelink using the one or more sidelink resources. The relay UE may further forward the data to at least one of the UE using the one or more sidelink resources when received from the base station on the access link using the one or more access link resources, or the base station using the one or more access link resources when received from the UE on the sidelink using the one or more sidelink resources.

In another implementation, the present disclosure provides apparatus and methods in which the base station determines, for a UE, quasi-colocation (QCL) information and a grant for one or both of one or more access link resources or one or more sidelink resources. The base station may further transmit, to the UE, the QCL information and the grant on a downlink communication channel.

These and other features of the present disclosure are discussed in detail below with regard toFIGS.1-11.

Several aspects of telecommunication systems will now be presented with reference to various apparatus and methods. These apparatus and methods will be described in the following detailed description and illustrated in the accompanying drawings by various blocks, components, circuits, processes, algorithms, etc. (collectively referred to as “elements”). These elements may be implemented using electronic hardware, computer software, or any combination thereof. Whether such elements are implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

By way of example, an element, or any portion of an element, or any combination of elements may be implemented as a “processing system” that includes one or more processors. Examples of processors include microprocessors, microcontrollers, graphics processing units (GPUs), central processing units (CPUs), application processors, digital signal processors (DSPs), reduced instruction set computing (RISC) processors, systems on a chip (SoC), baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gated logic, discrete hardware circuits, and other suitable hardware configured to perform the various functionality described throughout this disclosure. One or more processors in the processing system may execute software. Software may be construed broadly to mean instructions, instruction sets, code, code segments, program code, programs, subprograms, software components, applications, software applications, software packages, routines, subroutines, objects, executables, threads of execution, procedures, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

Accordingly, in one or more example embodiments, the functions described may be implemented in hardware, software, or any combination thereof. If implemented in software, the functions may be stored on or encoded as one or more instructions or code on a computer-readable medium. Computer-readable media includes computer storage media. Storage media may be any available media that can be accessed by a computer. By way of example, and not limitation, such computer-readable media can comprise a random-access memory (RAM), a read-only memory (ROM), an electrically erasable programmable ROM (EEPROM), optical disk storage, magnetic disk storage, other magnetic storage devices, combinations of the aforementioned types of computer-readable media, or any other medium that can be used to store computer executable code in the form of instructions or data structures that can be accessed by a computer.

FIG.1is a diagram illustrating an example of a wireless communications system and an access network100. The wireless communications system (also referred to as a wireless wide area network (WWAN)) includes base stations102, UEs104, an Evolved Packet Core (EPC)160, and another core network190(e.g., a 5G Core (5GC)).

In certain aspects, a relay UE104bmay include a relay communication component121for assisting with sidelink relay communications between a base station102aand a destination UE104a. The destination UE104amay have a first access link120adirectly with the base station102a, and a second communication link with the base station102avia a sidelink158awith the relay UE104, which has a second access link120bto the base station102a. The relay communication component121of the relay UE104bmay include a virtual multi-link component123, which may be selectively configured to serve as an additional virtual antenna panel for the destination UE104aby receiving downlink data from the base station102avia the second access link120b, or uplink data from the sidelink-assisted multi-link UE104avia the sidelink158a, and forwarding the downlink data to the destination UE104avia the sidelink158a, or the uplink data to the base station102avia the access link120b.

Correspondingly, the destination UE104amay include a UE multi-link communication component125configured to manage communications with both the relay UE104bvia the sidelink158aand the base station102avia the access link120a.

Similarly, the base station102amay include a base station multi-link communication component127configured to manage communications with both the relay UE104bvia the access link120band the sidelink-assisted multi-link UE104avia the access link120a.

Further details of these sidelink relay operational modes and operations performed by the relay UE104b, the destination UE104a, and the base station102aare discussed in more detail below.

The base stations102, including base station102a, may include macrocells (high power cellular base station) and/or small cells (low power cellular base station). The macrocells include base stations. The small cells include femtocells, picocells, and microcells.

The base stations102configured for 4G LTE (collectively referred to as Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC160through backhaul links132(e.g., S1 interface). The base stations102configured for 5G NR (collectively referred to as Next Generation RAN (NG-RAN)) may interface with 5G core network190through backhaul links184. In addition to other functions, the base stations102may perform one or more of the following functions: transfer of user data, radio channel ciphering and deciphering, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection setup and release, load balancing, distribution for non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and equipment trace, RAN information management (RIM), paging, positioning, and delivery of warning messages. The base stations102may communicate directly or indirectly (e.g., through the EPC160or core network190) with each other over backhaul links134(e.g., X2 interface). The backhaul links134may be wired or wireless.

The base stations102may wirelessly communicate with the UEs104, including relay UE104band sidelink-assisted multi-link UE104a. Each of the base stations102may provide communication coverage for a respective geographic coverage area110. There may be overlapping geographic coverage areas110. For example, the small cell102′ may have a coverage area110′ that overlaps the coverage area110of one or more macro base stations102. A network that includes both small cell and macrocells may be known as a heterogeneous network. A heterogeneous network may also include Home Evolved Node Bs (eNBs) (HeNBs), which may provide service to a restricted group known as a closed subscriber group (CSG). The communication links120, including access links120aand120b, between the base stations102and the UEs104may include uplink (UL) (also referred to as reverse link) transmissions from a UE104to a base station102and/or downlink (DL) (also referred to as forward link) transmissions from a base station102to a UE104. The communication links120may use multiple-input and multiple-output (MIMO) antenna technology, including spatial multiplexing, beamforming, and/or transmit diversity. The communication links may be through one or more carriers. The base stations102/UEs104may use spectrum up to Y MHz (e.g., 5, 10, 15, 20, 100, 400, etc. MHz) bandwidth per carrier allocated in a carrier aggregation of up to a total of Yx MHz (x component carriers) used for transmission in each direction. The carriers may or may not be adjacent to each other. Allocation of carriers may be asymmetric with respect to DL and UL (e.g., more or fewer carriers may be allocated for DL than for UL). The component carriers may include a primary component carrier and one or more secondary component carriers. A primary component carrier may be referred to as a primary cell (PCell) and a secondary component carrier may be referred to as a secondary cell (S Cell).

Certain UEs104, such as relay UE104band destination UE104a, may communicate with each other using device-to-device (D2D) communication link158, one example of which includes sidelink158a. The D2D communication link158may use the DL/UL WWAN spectrum. The D2D communication link158may use one or more sidelink channels, such as a physical sidelink broadcast channel (PSBCH), a physical sidelink discovery channel (PSDCH), a physical sidelink shared channel (PSSCH), and a physical sidelink control channel (PSCCH). D2D communication may be through a variety of wireless D2D communications systems, such as for example, FlashLinQ, WiMedia, Bluetooth, ZigBee, Wi-Fi based on the IEEE 802.11 standard, LTE, or NR.

The wireless communications system may further include a Wi-Fi access point (AP)150in communication with Wi-Fi stations (STAs)152via communication links154in a 5 GHz unlicensed frequency spectrum. When communicating in an unlicensed frequency spectrum, the STAs152/AP150may perform a clear channel assessment (CCA) prior to communicating in order to determine whether the channel is available.

The small cell102′ may operate in a licensed and/or an unlicensed frequency spectrum. When operating in an unlicensed frequency spectrum, the small cell102′ may employ NR and use the same 5 GHz unlicensed frequency spectrum as used by the Wi-Fi AP150. The small cell102′, employing NR in an unlicensed frequency spectrum, may boost coverage to and/or increase capacity of the access network.

A base station102, whether a small cell102′ or a large cell (e.g., macro base station), may include an eNB, gNodeB (gNB), or another type of base station. Some base stations, such as gNB180may operate in a traditional sub 6 GHz spectrum, in mmW frequencies, and/or near mmW frequencies in communication with the UE104. When the gNB180operates in mmW or near mmW frequencies, the gNB180may be referred to as an mmW base station. Extremely high frequency (EHF) is part of the RF in the electromagnetic spectrum. EHF has a range of 30 GHz to 300 GHz and a wavelength between 1 millimeter and 10 millimeters. Radio waves in the band may be referred to as a millimeter wave. Near mmW may extend down to a frequency of 3 GHz with a wavelength of 100 millimeters. The super high frequency (SHF) band extends between 3 GHz and 30 GHz, also referred to as centimeter wave. Communications using the mmW/near mmW radio frequency band (e.g., 3 GHz-300 GHz) has extremely high path loss and a short range. The mmW base station180may utilize beamforming182with the UE104to compensate for the extremely high path loss and short range.

The base station180may transmit a beamformed signal to the UE104in one or more transmit directions182′. The UE104may receive the beamformed signal from the base station180in one or more receive directions182″. The UE104may also transmit a beamformed signal to the base station180in one or more transmit directions. The base station180may receive the beamformed signal from the UE104in one or more receive directions. The base station180/UE104may perform beam training to determine the best receive and transmit directions for each of the base station180/UE104. The transmit and receive directions for the base station180may or may not be the same. The transmit and receive directions for the UE104may or may not be the same.

The EPC160may include a Mobility Management Entity (MME)162, other MMEs164, a Serving Gateway166, a Multimedia Broadcast Multicast Service (MBMS) Gateway168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway172. The MME162may be in communication with a Home Subscriber Server (HSS)174. The MME162is the control node that processes the signaling between the UEs104and the EPC160. Generally, the MME162provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway166, which itself is connected to the PDN Gateway172. The PDN Gateway172provides UE IP address allocation as well as other functions. The PDN Gateway172and the BM-SC170are connected to the IP Services176. The IP Services176may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services. The BM-SC170may provide functions for MBMS user service provisioning and delivery. The BM-SC170may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway168may be used to distribute MBMS traffic to the base stations102belonging 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.

The core network190may include a Access and Mobility Management Function (AMF)192, other AMFs193, a Session Management Function (SMF)194, and a User Plane Function (UPF)195. The AMF192may be in communication with a Unified Data Management (UDM)196. The AMF192is the control node that processes the signaling between the UEs104and the core network190. Generally, the AMF192provides QoS flow and session management. All user Internet protocol (IP) packets are transferred through the UPF195. The UPF195provides UE IP address allocation as well as other functions. The UPF195is connected to the IP Services197. The IP Services197may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services.

The base station may also be referred to as a gNB, Node B, evolved Node B (eNB), 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), a TRP, or some other suitable terminology. The base station102provides an access point to the EPC160or core network190for a UE104. Examples of UEs104include 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, a smart device, a wearable device, a vehicle, an electric meter, a gas pump, a large or small kitchen appliance, a healthcare device, an implant, a sensor/actuator, a display, or any other similar functioning device. Some of the UEs104may be referred to as IoT devices (e.g., parking meter, gas pump, toaster, vehicles, heart monitor, etc.). The UE104may also be referred to as a station, 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.

FIGS.2A-2Dinclude diagrams of example frame structures and resources that may be utilized in communications between the base stations102, the UEs104described in this disclosure.FIG.2Ais a diagram200illustrating an example of a first subframe within a 5G/NR frame structure.FIG.2Bis a diagram230illustrating an example of DL channels within a 5G/NR subframe.FIG.2Cis a diagram250illustrating an example of a second subframe within a 5G/NR frame structure.FIG.2Dis a diagram280illustrating an example of UL channels within a 5G/NR subframe. The 5G/NR frame structure may be FDD in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for either DL or UL, or may be TDD in which for a particular set of subcarriers (carrier system bandwidth), subframes within the set of subcarriers are dedicated for both DL and UL. In the examples provided byFIGS.2A,2C, the 5G/NR frame structure is assumed to be TDD, with subframe 4 being configured with slot format 28 (with mostly DL), where D is DL, U is UL, and X is flexible for use between DL/UL, and subframe 3 being configured with slot format 34 (with mostly UL). While subframes 3, 4 are shown with slot formats 34, 28, respectively, any particular subframe may be configured with any of the various available slot formats 0-61. Slot formats 0, 1 are all DL, UL, respectively. Other slot formats 2-61 include a mix of DL, UL, and flexible symbols. UEs are configured with the slot format (dynamically through DL control information (DCI), or semi-statically/statically through radio resource control (RRC) signaling) through a received slot format indicator (SFI). Note that the description infra applies also to a 5G/NR frame structure that is TDD.

Other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols. The symbols on DL may be cyclic prefix (CP) OFDM (CP-OFDM) symbols. The symbols on UL may be CP-OFDM symbols (for high throughput scenarios) or discrete Fourier transform (DFT) spread OFDM (DFT-s-OFDM) symbols (also referred to as single carrier frequency-division multiple access (SC-FDMA) symbols) (for power limited scenarios; limited to a single stream transmission). The number of slots within a subframe is based on the slot configuration and the numerology. For slot configuration 0, different numerologies μ0 to 5 allow for 1, 2, 4, 8, 16, and 32 slots, respectively, per subframe. For slot configuration 1, different numerologies 0 to 2 allow for 2, 4, and 8 slots, respectively, per subframe. Accordingly, for slot configuration 0 and numerology μ, there are 14 symbols/slot and 2μslots/subframe. The subcarrier spacing and symbol length/duration are a function of the numerology. The subcarrier spacing may be equal to 2μ*15 kHz, where μ is the numerology 0 to 5. As such, the numerology μ=0 has a subcarrier spacing of 15 kHz and the numerology μ=5 has a subcarrier spacing of 480 kHz. The symbol length/duration is inversely related to the subcarrier spacing.FIGS.2A-2Dprovide an example of slot configuration 0 with 14 symbols per slot and numerology μ=0 with 1 slot per subframe. The subcarrier spacing is 15 kHz and symbol duration is approximately 66.7 μs.

A resource grid may be used to represent the frame structure. Each time slot includes a resource block (RB) (also referred to as physical RBs (PRBs)) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme.

As illustrated inFIG.2A, some of the REs carry reference (pilot) signals (RS) for the UE. The RS may include demodulation RS (DM-RS) (indicated as RXfor one particular configuration, where 100× is the port number, but other DM-RS configurations are possible) and channel state information reference signals (CSI-RS) for channel estimation at the UE. The RS may also include beam measurement RS (BRS), beam refinement RS (BRRS), and phase tracking RS (PT-RS).

FIG.2Billustrates an example of various DL channels within a subframe of a frame. The physical downlink control channel (PDCCH) carries DCI within one or more control channel elements (CCEs), each CCE including nine RE groups (REGs), each REG including four consecutive REs in an OFDM symbol. A primary synchronization signal (PSS) may be within symbol 2 of particular subframes of a frame. The PSS is used by a UE104to determine subframe/symbol timing and a physical layer identity. A secondary synchronization signal (SSS) may be within symbol 4 of particular subframes of a frame. The SSS is used by a UE to determine a physical layer cell identity group number and radio frame timing. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine a physical cell identifier (PCI). Based on the PCI, the UE can determine the locations of the aforementioned DM-RS. The physical broadcast channel (PBCH), which carries a master information block (MIB), may be logically grouped with the PSS and SSS to form a synchronization signal (SS)/PBCH block. The MIB provides a number of RBs in the system bandwidth and a system frame number (SFN). The physical downlink shared channel (PDSCH) carries user data, broadcast system information not transmitted through the PBCH such as system information blocks (SIBs), and paging messages.

As illustrated inFIG.2C, some of the REs carry DM-RS (indicated as R for one particular configuration, but other DM-RS configurations are possible) for channel estimation at the base station. The UE may transmit DM-RS for the physical uplink control channel (PUCCH) and DM-RS for the physical uplink shared channel (PUSCH). The PUSCH DM-RS may be transmitted in the first one or two symbols of the PUSCH. The PUCCH DM-RS may be transmitted in different configurations depending on whether short or long PUCCHs are transmitted and depending on the particular PUCCH format used. Although not shown, the UE may transmit sounding reference signals (SRS). The SRS may be used by a base station for channel quality estimation to enable frequency-dependent scheduling on the UL.

FIG.2Dillustrates an example of various UL channels within a subframe of a frame. The PUCCH may be located as indicated in one configuration. The PUCCH carries uplink control information (UCI), such as scheduling requests, a channel quality indicator (CQI), a precoding matrix indicator (PMI), a rank indicator (RI), and HARQ ACK/NACK feedback. The PUSCH carries data, and may additionally be used to carry a buffer status report (BSR), a power headroom report (PHR), and/or UCI.

FIG.3is a diagram300of an example of a slot structure that may be used within a 5G/NR frame structure, e.g., for sidelink communication. This is merely one example, and other wireless communication technologies may have a different frame structure and/or different channels. A frame (10 ms) may be divided into 10 equally sized subframes (1 ms). Each subframe may include one or more time slots. Subframes may also include mini-slots, which may include 7, 4, or 2 symbols. Each slot may include 7 or 14 symbols, depending on the slot configuration. For slot configuration 0, each slot may include 14 symbols, and for slot configuration 1, each slot may include 7 symbols.

A resource grid may be used to represent the frame structure. Each time slot may include a resource block (RB) (also referred to as physical RBs (PRBs)) that extends 12 consecutive subcarriers. The resource grid is divided into multiple resource elements (REs). The number of bits carried by each RE depends on the modulation scheme. Some of the REs may comprise control information, e.g., along with demodulation RS (DM-RS). The control information may comprise Sidelink Control Information (SCI). In some implementations, at least one symbol at the beginning of a slot may be used by a transmitting device to perform a Listen Before Talk (LBT) operation prior to transmitting. In some implementations, at least one symbol may be used for feedback, as described herein. In some implementations, another symbol, e.g., at the end of the slot, may be used as a gap. The gap enables a device to switch from operating as a transmitting device to prepare to operate as a receiving device, e.g., in the following slot. Data may be transmitted in the remaining REs, as illustrated. The data may comprise the data message described herein. The position of any of the SCI, feedback, and LBT symbols may be different than the example illustrated inFIG.3. In some implementations, multiple slots may be aggregated together, and the example aggregation of two slots inFIG.3should not be considered limiting, as the aggregated number of slots may also be larger than two. When slots are aggregated, the symbols used for feedback and/or a gap symbol may be different that for a single slot.

FIG.4is a diagram of hardware components of an example transmitting and/or receiving (tx/rx) nodes410and450, which may be any combinations of base station102-UE104communications, and/or UE104-UE104communications in system100. For example, such communications may including, but are not limited to, communications such as a base station transmitting to a relay UE, a relay UE transmitting to a destination UE, a destination UE transmitting to a relay UE, or a relay UE transmitting to a base station in an access network. In one specific example, the tx/rx node410may be an example implementation of base station102and where tx/rx node450may be an example implementation of UE104. In the DL, IP packets from the EPC160may be provided to a controller/processor475. The controller/processor475implements layer 4 and layer 2 functionality. Layer 4 includes a radio resource control (RRC) layer, and layer 2 includes a service data adaptation protocol (SDAP) layer, a packet data convergence protocol (PDCP) layer, a radio link control (RLC) layer, and a medium access control (MAC) layer. The controller/processor475provides RRC layer functionality associated with broadcasting of system information (e.g., MIB, SIBs), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), inter radio access technology (RAT) mobility, and measurement configuration for UE measurement reporting; PDCP layer functionality associated with header compression/decompression, security (ciphering, deciphering, integrity protection, integrity verification), and handover support functions; RLC layer functionality associated with the transfer of upper layer packet data units (PDUs), error correction through ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

The transmit (TX) processor416and the receive (RX) processor470implement layer 1 functionality associated with various signal processing functions. Layer 1, which includes a physical (PHY) layer, may include error detection on the transport channels, forward error correction (FEC) coding/decoding of the transport channels, interleaving, rate matching, mapping onto physical channels, modulation/demodulation of physical channels, and MIMO antenna processing. The TX processor416handles mapping to signal constellations based on various modulation schemes (e.g., binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), M-phase-shift keying (M-PSK), M-quadrature amplitude modulation (M-QAM)). The coded and modulated symbols may then be split into parallel streams. Each stream may then be mapped to an OFDM subcarrier, multiplexed with a reference signal (e.g., pilot) in the time and/or frequency domain, and then combined together using an Inverse Fast Fourier Transform (IFFT) to produce a physical channel carrying a time domain OFDM symbol stream. The OFDM stream is spatially precoded to produce multiple spatial streams. Channel estimates from a channel estimator474may be used to determine the coding and modulation scheme, as well as for spatial processing. The channel estimate may be derived from a reference signal and/or channel condition feedback transmitted by the tx/rx node450. Each spatial stream may then be provided to a different antenna420via a separate transmitter418TX. Each transmitter418TX may modulate an RF carrier with a respective spatial stream for transmission.

At the tx/rx node450, each receiver454RX receives a signal through its respective antenna452. Each receiver454RX recovers information modulated onto an RF carrier and provides the information to the receive (RX) processor456. The TX processor468and the RX processor456implement layer 1 functionality associated with various signal processing functions. The RX processor456may perform spatial processing on the information to recover any spatial streams destined for the tx/rx node450. If multiple spatial streams are destined for the tx/rx node450, they may be combined by the RX processor456into a single OFDM symbol stream. The RX processor456then converts the OFDM symbol stream from the time-domain to the frequency domain using a Fast Fourier Transform (FFT). The frequency domain signal comprises a separate OFDM symbol stream for each subcarrier of the OFDM signal. The symbols on each subcarrier, and the reference signal, are recovered and demodulated by determining the most likely signal constellation points transmitted by the tx/rx node410. These soft decisions may be based on channel estimates computed by the channel estimator458. The soft decisions are then decoded and deinterleaved to recover the data and control signals that were originally transmitted by the tx/rx node410on the physical channel. The data and control signals are then provided to the controller/processor459, which implements layer 4 and layer 2 functionality.

The controller/processor459can be associated with a memory460that stores program codes and data. The memory460may be referred to as a computer-readable medium. In the UL, the controller/processor459provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, and control signal processing to recover IP packets from the EPC160. The controller/processor459is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

Similar to the functionality described in connection with the DL transmission by the tx/rx node410, the controller/processor459provides RRC layer functionality associated with system information (e.g., MIB, SIBs) acquisition, RRC connections, and measurement reporting; PDCP layer functionality associated with header compression/decompression, and security (ciphering, deciphering, integrity protection, integrity verification); RLC layer functionality associated with the transfer of upper layer PDUs, error correction through ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and reordering of RLC data PDUs; and MAC layer functionality associated with mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction through HARQ, priority handling, and logical channel prioritization.

Channel estimates derived by a channel estimator458from a reference signal or feedback transmitted by the tx/rx node410may be used by the TX processor468to select the appropriate coding and modulation schemes, and to facilitate spatial processing. The spatial streams generated by the TX processor468may be provided to different antenna452via separate transmitters454TX. Each transmitter454TX may modulate an RF carrier with a respective spatial stream for transmission.

The UL transmission is processed at the tx/rx node410in a manner similar to that described in connection with the receiver function at the tx/rx node450. Each receiver418RX receives a signal through its respective antenna420. Each receiver418RX recovers information modulated onto an RF carrier and provides the information to a RX processor470.

The controller/processor475can be associated with a memory476that stores program codes and data. The memory476may be referred to as a computer-readable medium. In the UL, the controller/processor475provides demultiplexing between transport and logical channels, packet reassembly, deciphering, header decompression, control signal processing to recover IP packets from the tx/rx node450. IP packets from the controller/processor475may be provided to the EPC160. The controller/processor475is also responsible for error detection using an ACK and/or NACK protocol to support HARQ operations.

In an implementation, at least one of the TX processor468, the RX processor456, and the controller/processor459may be configured to perform aspects in connection with components121,125, and/or127ofFIG.1.

In an implementation, at least one of the TX processor416, the RX processor470, and the controller/processor475may be configured to perform aspects in connection with components121,125, and/or127ofFIG.1.

Referring toFIGS.5,6, and7the present aspects generally relate to a relay communication scenario500,600, and700that includes relaying communications over a sidelink. As mentioned above, sidelink communication generally includes any type of device-to-device (D2D) communication. D2D communications may be used in applications such as, but not limited to, vehicle-to-anything (V2X) or vehicle to any other device type of communications, sensor networks, public safety-related communication services with limited infrastructure availability, or any other such type of application.

In the sidelink relay communication scenario500, a sidelink-assisted multi-link UE104amay establish a multi-link communication with one or more base stations102aand/or102bover two or more communication links, which include at least one direct link and at least one indirect link via a sidelink with a relay UE104b. In a first case, such as in the sidelink relay communication scenarios500and652, the sidelink-assisted multi-link UE104adirectly communicates with the base station102avia a first access link (AL)120a, and indirectly communicates with the base station102avia a sidelink158awith the relay UE104b, which has a second access link120bwith the base station102a.

In general, an access link such as access link120aor120bis a communication link between a respective UE and a respective base station (or gNB), which may also be referred to as a Uu interface in 4G LTE and/or in 5G NR technologies. In general, the sidelink158ais a communication link between UEs, which may be referred to as a PC5 interface in 4G LTE and/or in 5G NR technologies. In any case, the sidelink relay communication scenario500,502, and/or504may be utilized for improved diversity, e.g., sending the same data over two links (access link and sidelink), and/or improved throughput, e.g., sending different, independent data over each link. In an implementation, in a mmW system, this type of multi-link communication may be attained using multiple transmit/receive beams and multiple antenna panels (sub-arrays) between the UEs and/or between a respective UE and a respective base station/gNB.

Further, in a second case, such as in the sidelink relay communication scenario504, the sidelink-assisted multi-link UE104amay establish multiple links with multiple base stations102aand102b, which may be referred to as a multi-TRP architecture. In this case, the sidelink-assisted multi-link UE104adirectly communicates with the base station102avia a first access link (AL)120a, and indirectly communicates with the base station102bvia a sidelink158awith the relay UE104b, which has a second access link120bwith the base station102b. Additionally, in this case, the base stations102aand102bmay exchange communications over a backhaul link134a.

In the multi-link communication scenario600, the communications, a multi-link UE104amay establish a multi-link communication with one or more base stations102aand/or102bover two or more communication links, which include at least one access link (AL) to each of the base stations102aand/or102b. In a first case, such as in the multi-link communication scenarios600and602, the multi-link UE104adirectly communicates with the base station102avia a first access link (AL)120a, and may indirectly communicate with the base station102avia another access link (AL) with reflection at a radio clutter606, which comprised reflection paths120band120c. For example, the clutter606can be any object that can reflect/scatter radio waves, such as building surfaces, road signs, ground surface, etc. In general, an access link such as access link120aor120b/cis a communication link between a respective UE and a respective base station (or gNB), which may also be referred to as a Uu interface in 4G LTE and/or in 5G NR technologies. In any case, the multi-link communication scenario600,602, and/or604may be utilized for improved diversity, e.g., sending the same data over two separate links, and/or improved throughput, e.g., sending different, independent data over each link.

Further, in a second case, such as in the multi-link communication scenario604, the multi-link UE104amay establish multiple links with multiple base stations102aand102b, which may be referred to as a multi-transmit-receive point (multi-TRP) architecture. In this case, the multi-link UE104adirectly communicates with the base station102avia a first access link (AL)120a, and directly communicate with the base station102bvia another access link120b. Additionally, in this case, the base stations102aand102bmay exchange communications over a backhaul link134a. In an implementation, in a mmW system, this type of multi-link communication may be attained using multiple transmit/receive beams and multiple antenna panels (sub-arrays) between the UEs and/or between a respective UE and a respective base station/gNB.

Additionally, in the sidelink relay communication scenario500and/or multi-link communication scenario600, the communications exchanged between the base station102a/102b, relay UE104b, and sidelink-assisted multi-link UE104amay be uplink (UL) communications702and/or downlink (DL) communications704(seeFIG.7).

Referring toFIG.8, a resource allocation scheme800may support sidelink-assisted virtual multi-link. For example, base station (BS)802may be the same as or similar to base station102. The second UE (UE2) may be the same as or similar to relay UE104b, and the first UE (UE1) may correspond to sidelink-assisted multi-link UE104a. For example, UE1 may have one or more sidelinks established with one or more relay UEs such as UE2. For the DL/UL data transmission between BS802and UE1804, slot-aggregation and/or multi-slot scheduling grant808, which allocates at least one slot806in the access link and at least one slot818in the side link, may be used.

The grant808may be a semi-persistent and/or configured grant, or a dynamic grant given by a control channel (PDCCH810). A processing offset814between the access link slots and the sidelink slots may provide processing time at the relay UEs such as UE2. The slots for sidelink may contain resource SCI (e.g., via PSCCH816). The aggregated slots for both PDSCH812and PSSCH818may be used to transmit data according to the allocated resources on the access link or sidelink, respectively.

In one example, a relay UE or node (e.g., UE2804) may receive a grant (e.g., either implicit or explicit) for access link and sidelink resources from BS802. On the access link resource, relay UE (e.g., UE2) may receive data from the BS (BS802) or UE (UE1) (UL relaying). On the sidelink resources, relay UE (UE2) may forward the data received on the access link (e.g., potentially in a modified format) to the destination node (e.g., BS802or UE1804). Relaying may be contingent on the relay UE's (UE2) successful decoding of the access link. If the relay UE (UE2) fails in decoding data on the access link, the relay UE may skip relaying. If the SCI can be delivered to the destination node, the relay UE may notify the destination node of the decoding failure event.

In another example, a joint QCL indication may be transmitted to the destination UE (UE1). Specifically, transmission configuration indication (TCI) state/spatial relation can be configured as a combination of one or more QCL source reference signals on different links, such as access link reference signals (AL-RS(s)) and sidelink reference signals (SL-RS(s)). The base station (e.g., BE802), along with the access link and sidelink grant, may send joint access link-sidelink QCL information to destination UE (e.g., UE1804). For example, the joint QCL information may indicate the transmission and/or reception beams that the UE may use for access link and sidelink transmission and/or reception.

Further, synchronization signal block (SSB)/channel state information reference signal (CSI-RS) may become a DL/UL QCL sources and the sounding reference signal (SRS) may become UL QCL source. Specifically, the SL-RS may become a SL QCL source. Further, instead of SL-RS, SL UE's identifiers may be indicated, and the actual beam for sidelink communication between the UE and the identified SL UE may be implicitly determined (e.g., maintenance and selection SL beam may be up to UEs).

A sequence of joint TCI states/spatial relations may be configured and/or indicated for sweeping. For example, beam sweeping (one or more beams per link) and link sweeping (one or more links, e.g., AL and one or more SL(s)) over aggregated slots. With the scheduling DCI, only the index of the starting TCI state in the configured sequence may be indicated, and the TCI state for each aggregated slot may follow the order in the sequence with cycling. For semi-persistent scheduling and/or configured grant (e.g., for UL communication without dynamic scheduling by PDCCH), the TCI state for each aggregated slot may follow the order in the sequence starting from a fixed or pre-configured position, e.g., the first entry of the sequence.

Referring toFIG.9, an example method900of wireless communication may be performed by the relay UE104b, which may include one or more components as discussed inFIG.1,4, or11, and which may operate according to the virtual multi-link component123as discussed above with regard toFIGS.5-8.

At902, method900includes receiving, from a base station, a grant for one or both of one or more access link resources or one or more sidelink resources. For example, in an aspect, the relay UE104bmay operate one or any combination of antennas1165, RF front end1188, transceiver1102, processor1112, memory1116, modem1140, or relay communication component121to receive, from a base station102, a grant for one or both of one or more access link resources or one or more sidelink resources. For example, any of the above components may include receiving, from a base station, a grant for one or both of one or more access link resources or one or more sidelink resources.

At904, method900includes receiving data from at least one of the base station on an access link using the one or more access link resources, or a UE on a sidelink using the one or more sidelink resources. For example, in an aspect, the relay UE104bmay operate one or any combination of antennas1165, RF front end1188, transceiver1102, processor1112, memory1116, modem1140, or relay communication component121to receive data from at least one of the base station on an access link using the one or more access link resources, or a UE on a sidelink using the one or more sidelink resources. For example, any of the above components may include receiving data from at least one of the base station on an access link using the one or more access link resources, or a UE on a sidelink using the one or more sidelink resources.

At906, method900includes forwarding the data to at least one of the UE using the one or more sidelink resources when received from the base station on the access link using the one or more access link resources, or the base station using the one or more access link resources when received from the UE on the sidelink using the one or more sidelink resources. For example, in an aspect, the relay UE104bmay operate one or any combination of antennas1165, RF front end1188, transceiver1102, processor1112, memory1116, modem1140, or relay communication component121to forward the data to at least one of the UE using the one or more sidelink resources when received from the base station on the access link using the one or more access link resources, or the base station using the one or more access link resources when received from the UE on the sidelink using the one or more sidelink resources.

In some implementations, method900may further include determining whether data received on the access link has been successfully decoded, forwarding the data based on determining that the data received on the access link has been successfully decoded, and forgoing forwarding of the data based on determining that the data received on the access link has not been successfully decoded.

In some implementations, method900may further include transmitting a failure indication within sidelink control information to at least one of the UE or the base station.

In some implementations, receiving the grant may include receiving, on a PSCCH, the grant from the base station.

In some implementations, the one or more access link resources and the one or more sidelink resources may be offset in a time domain.

In some implementations, the one or more sidelink resources may include at least one resource for sidelink control information.

In some implementations, the relay node facilitates multi-link communication between the base station and the UE having a single antenna panel.

In some implementations, the relay node may serve as an additional virtual antenna panel for the UE.

In some implementations, the one or more access link resources may facilitate communication on a Uu interface.

In some implementations, the one or more sidelink resources may facilitate communication on a PC5 interface.

Referring toFIG.10, an example method1000of wireless communication may be performed by the base station102, which may include one or more components as discussed inFIG.1,4, or12, and which may operate according to the base station multi-link communication component127, as discussed above with regard toFIG.8.

At1002, method1000includes determining, for a UE, QCL information and a grant for one or both of one or more access link resources or one or more sidelink resources. For example, in an aspect, the base station102may operate one or any combination of antennas1265, RF front end1288, transceiver1202, processor1212, memory1216, modem1240, or base station multi-link communication component127to determine, for a UE, QCL information and a grant for one or both of one or more access link resources or one or more sidelink resources. For example, any of the above components may include determining, for a UE, QCL information and a grant for one or both of one or more access link resources or one or more sidelink resources.

At1004, method1000includes transmitting, to the UE, the QCL information and the grant on a downlink communication channel. For example, in an aspect, the base station102may operate one or any combination of antennas1265, RF front end1288, transceiver1202, processor1212, memory1216, modem1240, or base station multi-link communication component127to transmit, to the UE, the QCL information and the grant on a downlink communication channel. For example, any of the above components may include encoding and decoding algorithms for transmitting, to the UE, the QCL information and the grant on a downlink communication channel.

In other implementations, the QCL information may indicate one or more beams to be used for one or both of access link or sidelink communication.

In some implementations of method1000, the QCL information may indicate one or more QCL resources corresponding to one more access link reference signals, sidelink reference signals, or a combination thereof.

In some implementations, the QCL information may indicates a relay node identifier.

In some implementations, the QCL information may indicate a sequence of joint TCI states for combined beam and sidelink sweeping.

Referring toFIG.11, one example of an implementation of UE104, including relay UE104band/or sidelink-assisted multi-link UE104a, may include a variety of components, some of which have already been described above and are described further herein, including components such as one or more processors1112and memory1116and transceiver1102in communication via one or more buses1144, which may operate in conjunction with modem1140and/or configuration component198for communicating sidelink capability information.

In an aspect, the one or more processors1112can include a modem1140and/or can be part of the modem1140that uses one or more modem processors. Thus, the various functions related to configuration component198may be included in modem1140and/or processors1112and, in an aspect, can be executed by a single processor, while in other aspects, different ones of the functions may be executed by a combination of two or more different processors. For example, in an aspect, the one or more processors1112may include any one or any combination of a modem processor, or a baseband processor, or a digital signal processor, or a transmit processor, or a receiver processor, or a transceiver processor associated with transceiver1102. In other aspects, some of the features of the one or more processors1112and/or modem1140associated with configuration component198may be performed by transceiver1102.

Also, memory1116may be configured to store data used herein and/or local versions of applications1175or communicating component1142and/or one or more of its subcomponents being executed by at least one processor1112. Memory1116can include any type of computer-readable medium usable by a computer or at least one processor1112, such as random access memory (RAM), read only memory (ROM), tapes, magnetic discs, optical discs, volatile memory, non-volatile memory, and any combination thereof. In an aspect, for example, memory1116may be anon-transitory computer-readable storage medium that stores one or more computer-executable codes defining UE multi-link communication125and/or relay communication component121and/or one or more of its subcomponents, and/or data associated therewith, when UE104is operating at least one processor1112to execute multi-link communication125and/or relay communication component121and/or one or more of its subcomponents.

Transceiver1102may include at least one receiver1106and at least one transmitter1108. Receiver1106may include hardware and/or software executable by a processor for receiving data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). Receiver1106may be, for example, a radio frequency (RF) receiver. In an aspect, receiver1106may receive signals transmitted by at least one base station102. Additionally, receiver1106may process such received signals, and also may obtain measurements of the signals, such as, but not limited to, Ec/Io, signal-to-noise ratio (SNR), reference signal received power (RSRP), received signal strength indicator (RSSI), etc. Transmitter1108may include hardware and/or software executable by a processor for transmitting data, the code comprising instructions and being stored in a memory (e.g., computer-readable medium). A suitable example of transmitter1108may including, but is not limited to, an RF transmitter.

Moreover, in an aspect, UE104may include RF front end1188, which may operate in communication with one or more antennas1165and transceiver1102for receiving and transmitting radio transmissions, for example, wireless communications transmitted by at least one base station102or wireless transmissions transmitted by UE104. The one or more antennas1165may include one or more antenna panels and/or sub-arrays, such as may be used for beamforming. RF front end1188may be connected to one or more antennas1165and can include one or more low-noise amplifiers (LNAs)1190, one or more switches1192, one or more power amplifiers (PAs)1198, and one or more filters1196for transmitting and receiving RF signals.

In an aspect, LNA1190can amplify a received signal at a desired output level. In an aspect, each LNA1190may have a specified minimum and maximum gain values. In an aspect, RF front end1188may use one or more switches1192to select a particular LNA1190and its specified gain value based on a desired gain value for a particular application.

Further, for example, one or more PA(s)1198may be used by RF front end1188to amplify a signal for an RF output at a desired output power level. In an aspect, each PA1198may have specified minimum and maximum gain values. In an aspect, RF front end1188may use one or more switches1192to select a particular PA1198and its specified gain value based on a desired gain value for a particular application.

Also, for example, one or more filters1196can be used by RF front end1188to filter a received signal to obtain an input RF signal. Similarly, in an aspect, for example, a respective filter1196can be used to filter an output from a respective PA1198to produce an output signal for transmission. In an aspect, each filter1196can be connected to a specific LNA1190and/or PA1198. In an aspect, RF front end1188can use one or more switches1192to select a transmit or receive path using a specified filter1196, LNA1190, and/or PA1198, based on a configuration as specified by transceiver1102and/or processor1112.

As such, transceiver1102may be configured to transmit and receive wireless signals through one or more antennas1165via RF front end1188. In an aspect, transceiver may be tuned to operate at specified frequencies such that UE104can communicate with, for example, one or more base stations102or one or more cells associated with one or more base stations102. In an aspect, for example, modem1140can configure transceiver1102to operate at a specified frequency and power level based on the UE configuration of the UE104and the communication protocol used by modem1140.

In an aspect, modem1140can be a multiband-multimode modem, which can process digital data and communicate with transceiver1102such that the digital data is sent and received using transceiver1102. In an aspect, modem1140can be multiband and be configured to support multiple frequency bands for a specific communications protocol. In an aspect, modem1140can be multimode and be configured to support multiple operating networks and communications protocols. In an aspect, modem1140can control one or more components of UE104(e.g., RF front end1188, transceiver1102) to enable transmission and/or reception of signals from the network based on a specified modem configuration. In an aspect, the modem configuration can be based on the mode of the modem and the frequency band in use. In another aspect, the modem configuration can be based on UE configuration information associated with UE104as provided by the network during cell selection and/or cell reselection.

In an aspect, the processor(s)1112may correspond to one or more of the processors described in connection with the UE inFIG.4. Similarly, the memory1116may correspond to the memory described in connection with the UE inFIG.4.

Referring toFIG.12, one example of an implementation of base station102(e.g., a base station102,102a, and/or102b, as described above) may include a variety of components, some of which have already been described above, but including components such as one or more processors1212and memory1216and transceiver1202in communication via one or more buses1244, which may operate in conjunction with modem1240and base station multi-link communication component127.

The transceiver1202, receiver1206, transmitter1208, one or more processors1212, memory1216, applications1275, buses1244, RF front end1288, LNAs1290, switches1292, filters1296, PAs1298, and one or more antennas1265may be the same as or similar to the corresponding components of UE104, as described above, but configured or otherwise programmed for base station operations as opposed to UE operations.

In an aspect, the processor(s)1212may correspond to one or more of the processors described in connection with the base station inFIG.4. Similarly, the memory1216may correspond to the memory described in connection with the base station inFIG.4.

Some Further Examples

In one example, a method of wireless communications by a relay node comprises receiving, from a base station, a grant for one or both of one or more access link resources or one or more sidelink resources; receiving data from at least one of: the base station on an access link using the one or more access link resources, or a UE on a sidelink using the one or more sidelink resources; and forwarding the data to at least one of: the UE using the one or more sidelink resources when received from the base station on the access link using the one or more access link resources, or the base station using the one or more access link resources when received from the UE on the sidelink using the one or more sidelink resources.

One or more of the above examples can further include determining whether data received on the access link has been successfully decoded; forwarding the data based on determining that the data received on the access link has been successfully decoded; and forgoing forwarding of the data based on determining that the data received on the access link has not been successfully decoded.

One or more of the above examples can further include transmitting a failure indication within sidelink control information to at least one of the UE or the base station.

One or more of the above examples can further include receiving the grant includes receiving, on a PDCCH, the grant from the base station.

One or more of the above examples can further include wherein the one or more access link resources and the one or more sidelink resources are offset in a time domain.

One or more of the above examples can further include wherein the one or more sidelink resources include at least one resource for sidelink control information.

One or more of the above examples can further include wherein the relay node facilitates multi-link communication between the base station and the UE having a single antenna panel.

One or more of the above examples can further include wherein the relay node serves as an additional virtual antenna panel for the UE.

One or more of the above examples can further include wherein the one or more access link resources facilitate communication on a cellular (Uu) interface.

One or more of the above examples can further include wherein the one or more sidelink resources facilitate communication on a ProSe sidelink (PC5) interface.

In another example, a method of wireless communications by a base station, comprises determining, for a UE, QCL information and a grant for one or both of one or more access link resources or one or more sidelink resources; and transmitting, to the UE, the QCL information and the grant on a downlink communication channel.

One or more of the above examples can further include wherein the QCL information indicates one or more beams to be used for one or both of access link or sidelink communication.

One or more of the above examples can further include wherein the QCL information indicates one or more QCL resources corresponding to one more access link reference signals, sidelink reference signals, or a combination thereof.

One or more of the above examples can further include wherein the QCL information indicates a relay node identifier.

One or more of the above examples can further include wherein the QCL information indicates a sequence of joint TCI states for combined beam and sidelink sweeping.

It is understood that the specific order or hierarchy of blocks in the processes/flowcharts disclosed is an illustration of example approaches. Based upon design preferences, it is understood that the specific order or hierarchy of blocks in the processes/flowcharts may be rearranged. Further, some blocks may be combined or omitted. The accompanying method claims present elements of the various blocks in a sample order, and are not meant to be limited to the specific order or hierarchy presented.

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 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.” 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. Unless specifically stated otherwise, the term “some” refers to one or more. Combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” include any combination of A, B, and/or C, and may include multiples of A, multiples of B, or multiples of C. Specifically, combinations such as “at least one of A, B, or C,” “one or more of A, B, or C,” “at least one of A, B, and C,” “one or more of A, B, and C,” and “A, B, C, or any combination thereof” may be A only, B only, C only, A and B, A and C, B and C, or A and B and C, where any such combinations may contain one or more member or members of A, B, or C. 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. The words “module,” “mechanism,” “element,” “device,” and the like may not be a substitute for the word “means.” As such, no claim element is to be construed as a means plus function unless the element is expressly recited using the phrase “means for.”