Method and apparatus for sparse code multiple access (SCMA) codebook design

Abstract

The present disclosure describes methods, apparatuses, and computer-readable media for multi-layer transmission in a wireless network. For example, the method may include generating a set of binary data bits for resources of each of a plurality of layers, mapping the set of binary data bits of each of the plurality of layers to a corresponding codeword in a signal constellation, combining the codewords, and transmitting the combined codewords to a receiver in the wireless network. Thus, multi-layer transmission in a wireless network is achieved.

Description

[0001] This application is a divisional application of a Chinese patent application with an application date of March 30, 2017 and an application number of 201780019651.7.

[0002] Priority Claims

[0003] This patent application claims priority to U.S. Provisional Patent Application No. 62 / 320,298, filed on April 8, 2016, entitled "Techniques for Sparse Code Multiple Access (SCMA) Codebook Design", and U.S. Patent Application No. 15 / 266,484, filed on September 15, 2016, entitled "Techniques for Sparse Code Multiple Access (SCMA) Codebook Design". Both of these applications are assigned to the assignee of this application and are hereby expressly incorporated by reference in their entirety. Background Art

[0004] This disclosure generally relates to communication systems, and more particularly, to codebook design in sparse code multiple access (SCMA) networks.

[0005] Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasting. A typical wireless communication system may employ multiple access techniques that are capable of supporting communication with multiple users by sharing available system resources. Examples of such multiple access techniques include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems.

[0006] These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate at the urban, national, regional, and even global levels. An example telecommunication standard is Long Term Evolution (LTE). LTE is an enhanced set of the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by the Third Generation Partnership Project (3GPP). LTE is designed to support mobile broadband access by using OFDMA on the downlink, SC-FDMA on the uplink, and using multiple input multiple output (MIMO) antenna technology to improve spectral efficiency, reduce costs, and improve services. However, as the demand for mobile broadband access continues to increase, further improvements to LTE technology are needed. These improvements may also be applicable to other multiple access technologies and telecommunication standards that employ these technologies.

[0007] In a wireless communication system employing CDMA, data symbols are spread over orthogonal code sequences or approximately orthogonal code sequences. Prior to applying the spreading sequences, binary codes are mapped to quadrature amplitude modulation (QAM) symbols. Although this type of coding can provide a relatively high coding rate, it may not be sufficient to meet the requirements of current wireless networks.

[0008] Therefore, new techniques or mechanisms for achieving higher coding rates are needed to meet the growing demands of wireless networks. Summary of the Invention

[0009] A brief overview of one or more aspects is presented below to provide a basic understanding of these aspects. This overview is not an extensive review of all contemplated aspects and is not intended to identify key or critical elements of all aspects or to describe the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that follows.

[0010] According to one example, a method for multi-layer transmission in a wireless network is provided. The method includes, at a transmitter, generating a group of binary data bits for resources of each of a plurality of layers; at the transmitter, mapping the group of binary data bits of each of the plurality of layers to a corresponding codeword in a signal constellation, wherein the mapping is at least based on maximizing the distance between the codewords within each of the plurality of layers; combining the codewords at the transmitter; and transmitting the combined codewords from the transmitter to a receiver in the wireless network.

[0011] In another example, an apparatus for multi-layer transmission in a wireless network is provided. The apparatus includes means for generating a group of binary data bits for resources of each of a plurality of layers at a transmitter; means for mapping the group of binary data bits of each of the plurality of layers to a corresponding codeword in a signal constellation at the transmitter, wherein the mapping is at least based on maximizing the distance between the codewords within each of the plurality of layers; means for combining the codewords at the transmitter; and means for transmitting the combined codewords from the transmitter to a receiver in the wireless network.

[0012] In yet another example, an apparatus for multi-layer transmission in a wireless network is provided. The apparatus includes: a memory; and at least one processor coupled to the memory and configured to: at a transmitter, generate a set of binary data bits for resources of each of a plurality of layers; at the transmitter, map the set of binary data bits of each of the plurality of layers to a corresponding codeword in a signal constellation, wherein the mapping is at least based on maximizing the distance between the codewords within each of the plurality of layers; at the transmitter, combine the codewords; and transmit the combined codewords from the transmitter to a receiver in the wireless network.

[0013] Additionally, in another example, a computer-readable medium storing computer-executable code for multi-layer transmission is provided. The computer-readable medium includes code for: at a transmitter, generating a set of binary data bits for resources of each of a plurality of layers; at the transmitter, mapping the set of binary data bits of each of the plurality of layers to a corresponding codeword in a signal constellation, wherein the mapping is at least based on maximizing the distance between the codewords within each of the plurality of layers; at the transmitter, combining the codewords; and transmitting the combined codewords from the transmitter to a receiver in the wireless network.

[0014] To achieve the foregoing and related purposes, one or more aspects include the features described in detail below and particularly pointed out in the claims. The following description and the drawings set forth certain illustrative features of the one or more aspects in detail. However, these features are merely representative of the various ways in which the principles of the various aspects may be employed, and this description is intended to include all such aspects and their equivalents. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The drawings are presented to assist in the description of various aspects of the present disclosure and are provided only for illustration of the aspects and not for limitation thereof. The drawings include like reference numerals for like elements and may use dashed lines to represent optional components or actions.

[0016] Figure 1 is a diagram illustrating an example of a wireless communication system and an access network in accordance with various aspects of the present disclosure, including a base station having aspects with a multi-layer transmission component for multi-layer transmission as described herein.

[0017] Figure 2A , 2B, 2C, and 2D are diagrams respectively illustrating LTE examples of a DL frame structure, DL channels within the DL frame structure, a UL frame structure, and UL channels within the UL frame structure.

[0018] Figure 3is a diagram illustrating an example of an evolved Node B (eNB) and a User Equipment (UE) in an access network according to various aspects of the present disclosure, where the UE includes aspects of a multi-layer transmission component for multi-layer transmission as described herein.

[0019] Figure 4 is a schematic diagram of a wireless communication system according to various aspects of the present disclosure, including a base station having aspects of a multi-layer transmission component for multi-layer transmission.

[0020] Figure 5 is a diagram illustrating aspects of multi-layer transmission in a wireless communication system according to various aspects of the present disclosure.

[0021] Figure 6 is a diagram illustrating aspects of resource allocation between layers in a wireless communication system according to various aspects of the present disclosure.

[0022] Figure 7 is a diagram illustrating a non-limiting example of mapping binary data bits 700 in a set of layers to codewords in a wireless communication system such as system 100 ( Figure 1 ) or system 400 ( Figure 4 ).

[0023] Figure 7 is a diagram illustrating aspects of a downlink subframe structure with different multi-user multiple-input multiple-output (MU-MIMO) according to various aspects of the present disclosure.

[0024] Figure 8 is a diagram illustrating aspects of mapping binary data bits to codewords according to various aspects of the present disclosure.

[0025] Figure 9A -B illustrates an example of codebook design in a wireless communication system.

[0026] Figure 10 、 11A -C and 12A-B illustrate codebook performance according to various aspects of the present disclosure.

[0027] Figure 13 is a flowchart of aspects of multi-layer transmission that can be performed by the Figure 4 multi-layer transmission component.

[0028] Figure 14 is a conceptual data flow diagram illustrating the data flow between different units / components in an exemplary apparatus according to various aspects of the present disclosure, the exemplary apparatus including a multi-layer transmission component for multi-layer transmission.

[0029] Figure 15FIG. is an example diagram illustrating a hardware implementation of an apparatus employing a processing system including a multi-layer component for multi-layer transmission in accordance with various aspects of the present disclosure. DETAILED DESCRIPTION

[0030] The following detailed description presented in conjunction with the accompanying 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 the 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 to avoid obscuring such concepts.

[0031] Certain aspects of a telecommunications system will now be presented with reference to various apparatuses and methods. These apparatuses 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 can be implemented using electronic hardware, computer software, or any combination thereof. Whether an element is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system.

[0032] By way of example, an element, or any portion of an element, or any combination of elements can be implemented as a "processing system" including 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, system on a chip (SoC) processors, baseband processors, field programmable gate arrays (FPGAs), programmable logic devices (PLDs), state machines, gate logic, discrete hardware circuits, and other suitable hardware. One or more processors in the processing system can execute software. Software shall 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, executable programs, execution threads, programs, functions, etc., whether referred to as software, firmware, middleware, microcode, hardware description language, or otherwise.

[0033] Thus, in one or more example aspects, the described functionality may be implemented in hardware, software, or any combination thereof. If implemented in software, the functionality 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 is accessible by a computer. By way of example and not limitation, such computer-readable media may include random access memory (RAM), read-only memory (ROM), 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 accessible by a computer.

[0034] This disclosure relates to multi-layer transmission at a base station and / or user equipment. For example, insert a brief description of the invention.

[0035] Figure 1 FIG. 1 is a diagram illustrating an example of a wireless communication system and access network 100 in accordance with various aspects of the present disclosure, including at least one base station 102 configured to include a multi-layer transmission component 420 for multi-layer transmission to at least one UE 104. The wireless communication system 100 (also referred to as a wireless wide area network (WWAN)) includes base stations 102, UEs 104, and an evolved packet core (EPC) 160. The base stations 102 may include macro cells (high-power cellular base stations) and / or small cells (low-power cellular base stations). The macro cells include eNBs. The small cells include femto cells, pico cells, and micro cells.

[0036] The base stations 102 (collectively referred to as the evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN)) interface with the EPC 160 via a backhaul link 132 (e.g., the S1 interface). Among other functions, the base stations 102 may perform one or more of the following functions: transmission of user data, wireless channel encryption and decryption, integrity protection, header compression, mobility control functions (e.g., handover, dual connectivity), inter-cell interference coordination, connection establishment and release, load balancing, distribution of non-access stratum (NAS) messages, NAS node selection, synchronization, radio access network (RAN) sharing, multimedia broadcast multicast service (MBMS), subscriber and device tracking, radio access network information management (RIM), paging, positioning, and delivery of warning messages. The base stations 102 may communicate directly or indirectly (e.g., via the EPC 160) with each other via a backhaul link 134 (e.g., the X2 interface). The backhaul link 134 may be wired or wireless.

[0037] Base station 102 can communicate wirelessly with UE 104. Each of the base stations 102 can provide communication coverage for a corresponding geographic coverage area 110. There can be overlapping geographic coverage areas 110. For example, small cell 102' can have a coverage area 110' that overlaps with the coverage areas 110 of one or more macro base stations 102. A network including both small cells and macro cells can be referred to as a heterogeneous network. The heterogeneous network can also include a Home evolved Node B (HeNB) that can provide service to a restricted group called a Closed Subscriber Group (CSG). The communication link 120 between the base station 102 and the UE 104 can include an uplink (UL) (also referred to as a reverse link) transmission from the UE 104 to the base station 102 and / or a downlink (DL) (also referred to as a forward link) transmission from the base station 102 to the UE 104. The communication link 120 can use MIMO antenna technology, including spatial multiplexing, beamforming, and / or transmit diversity. The communication link can be over one or more carriers. The base station 102 / UE 104 can use a spectrum with a bandwidth of up to Y MHz (e.g., 5, 10, 15, 20 MHz) per carrier allocated in carrier aggregation of up to a total of Yx MHz (x component carriers) for transmission in each direction. The allocation of carriers can be asymmetric with respect to the DL and UL (e.g., more or fewer carriers can be allocated for the DL than for the UL). The component carriers can include a primary component carrier and one or more secondary component carriers. The primary component carrier can be referred to as the Primary Cell (PCell), and the secondary component carriers can be referred to as Secondary Cells (SCells).

[0038] The wireless communication system 100 can also include a Wi-Fi Access Point (AP) 150 that communicates with a Wi-Fi Station (STA) 152 via a communication link 154 in the 5 GHz unlicensed spectrum. When communicating in the unlicensed spectrum, the STA 152 / AP 150 can perform a Clear Channel Assessment (CCA) before communicating to determine whether the channel is available.

[0039] The small cell 102' can operate in licensed and / or unlicensed spectrum. When operating in the unlicensed spectrum, the small cell 102' can adopt LTE and use the same 5 GHz unlicensed spectrum as that used by the Wi-Fi AP 150. The small cell 102' adopting LTE in the unlicensed spectrum can enhance the coverage of the access network and / or increase the capacity of the access network. LTE in the unlicensed spectrum can be referred to as LTE Unlicensed (LTE-U), Licensed-Assisted Access (LAA), or MuLTEfire.

[0040] The EPC 160 may include a Mobility Management Entity (MME) 162, other MMEs 164, a Serving Gateway 166, a Multimedia Broadcast Multicast Service (MBMS) Gateway 168, a Broadcast Multicast Service Center (BM-SC) 170, and a Packet Data Network (PDN) Gateway 172. The MME 162 may communicate with a Home Subscriber Server (HSS) 174. The MME 162 is a control node that processes signaling between the UE 104 and the EPC 160. Generally, the MME 162 provides bearer and connection management. All User Internet Protocol (IP) packets are transported through the Serving Gateway 166, which itself is connected to the PDN Gateway 172. The PDN Gateway 172 provides IP address allocation and other functions for the UE. The PDN Gateway 172 and the BM-SC 170 are connected to an IP service 176. The IP service 176 may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a Packet-Switched Streaming Service (PSS), and / or other IP services. The BM-SC 170 may provide functions for MBMS user service configuration and delivery. The BM-SC 170 may serve as an entry point for content provider MBMS transmissions, 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 Gateway 168 may be used to distribute MBMS traffic to base stations 102 belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area for a broadcast specific service, and may be responsible for session management (start / stop) and collecting charging information related to eMBMS.

[0041] A base station may also be referred to as a Node B, an access point, a base station transceiver, a radio base station, a radio transceiver, a transceiver function, a Basic Service Set (BSS), an Extended Service Set (ESS), or some other suitable term. The eNB 106 provides an access point to the EPC 160 for the UE 104. Examples of the UE 104 include a cellular phone, a smartphone, a Session Initiation Protocol (SIP) phone, a laptop computer, a Personal Digital Assistant (PDA), a satellite radio, a Global Positioning System, a multimedia device, a video device, a digital audio player (e.g., an MP3 player), a camera, a game console, a tablet computer, a smart device, a wearable device, or any other similar functional device. The UE 104 may 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 communication device, a remote device, a mobile subscriber station, an access terminal, a mobile terminal, a wireless terminal, a remote terminal, a cell phone, a user agent, a mobile client, a client, or some other suitable term.

[0042] Figure 2AFIG. 200 is an example diagram illustrating a DL frame structure in LTE according to various aspects of the present disclosure, which may be an example of a frame structure that can be transmitted by at least one base station 102 of a multi-layer transmission component 420 configured to transmit data.

[0043] Figure 2B FIG. 230 is an example diagram illustrating examples of channels in a DL frame structure that can be transmitted by base station 102 and used by UE 104 as described herein.

[0044] Figure 2C FIG. 250 is an example diagram illustrating an example of a UL frame structure that can be used by UE 104 in LTE.

[0045] Figure 2D FIG. 280 is an example diagram illustrating examples of channels within the UL frame structure that can be used by UE 104 in LTE. Other wireless communication technologies may have different frame structures and / or different channels.

[0046] In LTE, a frame (10 ms) can be divided into 10 equally sized subframes. Each subframe can include two consecutive time slots. A resource grid can be used to represent the two time slots, and each time slot includes one or more time-concurrent resource blocks (RBs) (also referred to as physical RBs (PRBs)). The resource grid is divided into multiple resource elements (REs). In LTE, for a normal cyclic prefix, an RB contains 12 consecutive subcarriers in the frequency domain and 7 consecutive symbols in the time domain (for DL, OFDM symbols; for UL, SC-FDMA symbols), for a total of 84 REs. For an extended cyclic prefix, an RB contains 12 consecutive subcarriers in the frequency domain and 6 consecutive symbols in the time domain, for a total of 72 REs. The number of bits carried by each RE depends on the modulation scheme. Additionally, in the present disclosure, an RB as described above may also be referred to as a "resource", an "orthogonal resource", etc.

[0047] As Figure 2A shown, some of the REs carry DL reference (pilot) signals (DL-RS) for channel estimation at the UE. The DL-RS can include cell-specific reference signals (CRS) (sometimes also referred to as common RS), UE-specific reference signals (UE-RS), and channel state information reference signals (CSI-RS). Figure 2A Illustrates CRSs for antenna ports 0, 1, 2, and 3 (denoted as R0, R1, R2, and R3 respectively), a UE-RS for antenna port 5 (denoted as R5), and a CSI-RS for antenna port 15 (denoted as R).

[0048] Figure 2BIllustrates an example of various channels within the DL subframe of a frame. The Physical Control Format Indicator Channel (PCFICH) is within symbol 0 of slot 0 and carries a Control Format Indicator (CFI) for indicating whether the Physical Downlink Control Channel (PDCCH) occupies 1, 2, or 3 symbols ( Figure 2B illustrates a PDCCH that occupies 3 symbols). The PDCCH carries Downlink Control Information (DCI) within one or more Control Channel Elements (CCEs), where each CCE includes nine Resource Element Groups (REGs), and each REG includes four consecutive Resource Elements (REs) in an OFDM symbol. The UE can be configured with a UE-specific Enhanced PDCCH (ePDCCH) that also carries DCI. The ePDCCH can have 2, 4, or 8 Resource Block (RB) pairs ( Figure 2B shows two RB pairs, with each subset including one RB pair). The Physical Hybrid Automatic Repeat reQuest (ARQ) (HARQ) Indicator Channel (PHICH) is also within symbol 0 of slot 0 and carries a HARQ Indicator (HI) that indicates HARQ Acknowledgment (ACK) / Negative ACK (NACK) feedback based on the Physical Uplink Shared Channel (PUSCH). The Primary Synchronization Channel (PSCH) is within symbol 6 of slot 0 in subframes 0 and 5 of the frame and carries a Primary Synchronization Signal (PSS) used by the UE to determine subframe timing and the physical layer identity. The Secondary Synchronization Channel (SSCH) is within symbol 5 of slot 0 in subframes 0 and 5 of the frame and carries a Secondary Synchronization Signal (SSS) used by the UE to determine the physical layer cell identity group number. Based on the physical layer identity and the physical layer cell identity group number, the UE can determine the Physical Cell Identifier (PCI). Based on the PCI, the UE can determine the location of the above-mentioned DL-RS. The Physical Broadcast Channel (PBCH) is within symbols 0, 1, 2, 3 of slot 1 in subframe 0 of the frame and carries the Master Information Block (MIB). The MIB provides the number of RBs in the DL system bandwidth, the PHICH configuration, and the System Frame Number (SFN). The Physical Downlink Shared Channel (PDSCH) carries user data, broadcast system information not sent via the PBCH, such as System Information Blocks (SIBs), and paging messages.

[0049] As Figure 2C shown, some of the REs carry Demodulation Reference Signals (DM-RS) for channel estimation at the eNB. The UE can additionally transmit a Sounding Reference Signal (SRS) in the last symbol of a subframe. The SRS can have a comb structure, and the UE can transmit the SRS on one of the combs. The eNB can use the SRS for channel quality estimation to enable frequency-dependent scheduling on the UL. Figure 2DIllustrates an example of various channels within the UL subframe of a frame. The Physical Random Access Channel (PRACH) can be within one or more subframes of a frame based on the PRACH configuration. The PRACH can include six consecutive RB pairs within a subframe. The PRACH allows the UE to perform initial system access and achieve UL synchronization. The Physical Uplink Control Channel (PUCCH) can be located at the edge of the UL system bandwidth. The PUCCH carries uplink control information (UCI), such as scheduling requests, Channel Quality Indicator (CQI), Precoding Matrix Indicator (PMI), Rank Indicator (RI), and HARQ ACK / NACK feedback. The PUSCH carries data and can also be used to carry Buffer Status Report (BSR), Power Headroom Report (PHR), and / or UCI.

[0050] Figure 3 Is a block diagram of an eNB 102 communicating with a UE 104 in an access network. In one aspect, the base station 102 and / or the UE 104 can be configured to include a multi-layer transmission component 420. In one aspect, the multi-layer transmission component 420 can be configured to manage transmissions to multiple layers. In the DL, IP packets from the EPC 160 can be provided to the controller / processor 375. The controller / processor 375 implements layer 3 and layer 2 functions. Layer 3 includes the Radio Resource Control (RRC) layer, and layer 2 includes the Packet Data Convergence Protocol (PDCP) layer, the Radio Link Control (RLC) layer, and the Medium Access Control (MAC) layer. The controller / processor 375 provides RRC layer functions associated with the broadcast of system information (e.g., MIB, SIB), RRC connection control (e.g., RRC connection paging, RRC connection establishment, RRC connection modification, and RRC connection release), mobility between radio access technologies (RATs), and measurement configuration for UE measurement reports; PDCP layer functions associated with header compression / decompression, security (encryption, decryption, integrity protection, integrity verification), and handover support functions; RLC layer functions associated with the transfer of upper layer packet data units (PDUs), error correction via ARQ, concatenation, segmentation, and reassembly of RLC service data units (SDUs), re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions associated with the mapping between logical channels and transport channels, multiplexing of MAC SDUs into transport blocks (TBs), demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0051] The transmit (TX) processor 316 and the receive (RX) processor 370 implement layer 1 functions associated with various signal processing functions. Layer 1, which includes the physical (PHY) layer, may include error detection on the transport channel, forward error correction (FEC) encoding / decoding of the transport channel, interleaving, rate matching, mapping to the physical channel, modulation / demodulation of the physical channel, and MIMO antenna processing. The TX processor 316 processes the mapping to the signal constellation 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 encoded and modulated symbols may then be separated into parallel streams. Each stream may then be mapped to OFDM subcarriers, multiplexed with reference signals (e.g., pilots) in the time domain and / or frequency domain, and then combined together using an inverse fast Fourier transform (IFFT) to generate a physical channel carrying a stream of time-domain OFDM symbols. The OFDM stream is space precoded to generate multiple spatial streams. Channel estimates from the channel estimator 374 may be used to determine the encoding and modulation schemes and the spatial processing. The channel estimates may be derived based on channel condition feedback transmitted by the UE 104 and / or reference signals. Each spatial stream may then be provided to a different antenna 320 via a separate transmitter 318TX. Each transmitter 318TX may modulate an RF carrier with the corresponding spatial stream for transmission.

[0052] At the UE 104, each receiver 354RX receives signals via its corresponding antenna 352. Each receiver 354RX recovers the information modulated onto the RF carrier and provides the information to the receive (RX) processor 356. The TX processor 368 and the RX processor 356 implement layer 1 functions associated with various signal processing functions. The RX processor 356 may perform spatial processing on the information to recover any spatial streams destined for the UE 104. If multiple spatial streams are destined for the UE 104, they may be combined by the RX processor 356 into a single OFDM symbol stream. The RX processor 356 then uses a fast Fourier transform (FFT) to convert the OFDM symbol stream from the time domain to the frequency domain. For each subcarrier of the OFDM signal, the frequency domain signal includes a separate OFDM symbol stream. The symbols and reference signals on each subcarrier are recovered and demodulated by determining the most likely signal constellation points transmitted by the eNB 310. These soft decisions may be based on channel estimates computed by the channel estimator 358. The soft decisions are then decoded and deinterleaved to recover the data and control signals originally transmitted by the eNB 310 on the physical channel. The data and control signals are then provided to the controller / processor 359 that implements layer 3 and layer 2 functions.

[0053] The controller / processor 359 may be associated with a memory 360 that stores program code and data. The memory 360 may be referred to as a computer-readable medium. In the UL, the controller / processor 359 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, and control signal processing to recover IP packets from the EPC 160. The controller / processor 359 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0054] Similar to the functions described in conjunction with DL transmissions performed by the eNB 310, the controller / processor 359 provides RRC layer functions associated with system information (e.g., MIB, SIB) acquisition, RRC connection, and measurement reporting; PDCP layer functions related to header compression / decompression and security (encryption, decryption, integrity protection, integrity verification); RLC layer functions associated with the transfer of upper layer PDUs, error correction via ARQ, concatenation, segmentation, and reassembly of RLC SDUs, re-segmentation of RLC data PDUs, and re-ordering of RLC data PDUs; and MAC layer functions related to the mapping between logical channels and transport channels, multiplexing of MAC SDUs onto TBs, demultiplexing of MAC SDUs from TBs, scheduling information reporting, error correction via HARQ, priority handling, and logical channel prioritization.

[0055] Channel estimates derived by the channel estimator 358 based on feedback or reference signals transmitted by the eNB 310 may be used by the TX processor 368 to select appropriate coding and modulation schemes and to facilitate spatial processing. The spatial streams generated by the TX processor 368 may be provided to different antennas 352 via separate transmitters 354TX. Each transmitter 354TX may modulate an RF carrier using the corresponding spatial stream for transmission.

[0056] At the eNB 310, UL transmissions are processed in a manner similar to that described in conjunction with the receiver function at the UE 104. Each receiver 318RX receives signals via its corresponding antenna 320. Each receiver 318RX recovers the information modulated onto the RF carrier and provides the information to the RX processor 370.

[0057] The controller / processor 375 may be associated with a memory 376 that stores program code and data. The memory 376 may be referred to as a computer-readable medium. In the UL, the controller / processor 375 provides demultiplexing between transport channels and logical channels, packet reassembly, decryption, header decompression, control signal processing to recover IP packets from the UE 104. The IP packets from the controller / processor 375 may be provided to the EPC 160. The controller / processor 375 is also responsible for error detection using the ACK and / or NACK protocols to support HARQ operations.

[0058] Reference Figure 4 , in one aspect, a wireless communication system 400 (which may be the same as or similar to Figure 1 the wireless communication system and access network 100) includes a plurality of UEs (UEs 402, 404, 406, 408, 410, and 412, which may be the same as or similar to Figure 1 the UE 104 in) within the communication coverage of at least one base station 102. The base station 102 (collectively referred to as the evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN)) may interface with the EPC (such as Figure 1 the EPC 160 in) via a backhaul link 132 (e.g., the S1 interface). In one aspect, the base station 102 may include one or more processors (not shown) and optionally a memory (not shown), which may operate in combination with a multi-layer transmission component 420 for sending data to the UEs. In an additional or alternative aspect, any one of the UEs (e.g., (UEs 402, 404, 406, 408, 410, and / or 412)) may also include a multi-layer transmission component 420, one or more processors (not shown), and optionally a memory (not shown), which may operate in combination with a multi-layer transmission component 420 for sending data from the UE to the base station.

[0059] In one aspect, the base station 102, which may include the multi-layer transmission component 420, may send a transmission (e.g., an SCMA transmission) 432 to one or more UEs (e.g., 402, 404, 406, 408, 410, and / or 412) on the downlink 120-a (for simplicity, only one downlink is shown). Although in Figure 4Six UEs (referred to as users or layers in this disclosure) are shown, but the disclosure is not limited to six layers. In the example, four resources for sending data to six layers (e.g., users / UEs) are available at the base station. On each layer, only two resources can be used to send data, and no data is sent on the unused resources. On each layer, the data available for transmission on the downlink is converted into binary data bits. Then, the binary data bits are mapped to codewords of a signal constellation (e.g., the codebook of the corresponding layer) to maximize the distance between the codewords of the resources. The codewords of all layers are combined to generate a combined codeword before transmission.

[0060] For example, base station 102 and / or the multi-layer transmission component 420 may be configured to perform multi-layer transmission (e.g., transmission 432) by: generating a set of binary data bits for the resources of each of the layers, mapping each of the set of binary data bits to a corresponding codeword in a signal constellation, wherein the mapping of each of the set of binary data bits is at least based on maximizing the distance between the codewords within each of the layers, combining the codewords, and transmitting the combined codeword. Additionally, transmission 432 may be a sparse code multiple access transmission to implement multi-dimensional coded modulation for non-orthogonal multiple access to meet the growing demands of wireless networks.

[0061] In another aspect, for example, one or more of the UEs (e.g., UEs 402, 404, 406, 408, 410, and / or 412) may include a multi-layer transmission component 420 and may transmit a transmission (e.g., SCMA transmission) on the uplink 120-b (only one uplink is shown for simplicity) to the base station. When the uplink is synchronized, the transmissions from one or more UEs are combined at the receiving antennas of the base station. Additionally, the base station uses the codebook associated with each layer to decode the data transmitted on the corresponding layer to determine the data transmitted on each layer. Further, the base station may allocate more than one layer to a UE.

[0062] In yet another aspect, the multi-layer transmission component 420 may include a binary data generation component 422, a mapping component 424, a combining component 426, and / or a transmitting component 428 for performing multi-layer transmission. Additionally, the multi-layer transmission component 420 and other components (422, 424, 426, and / or 428) may reside at the base station 102 for multi-layer transmission from the base station to one or more UEs, and / or at the UE 104 for multi-layer transmission from one or more UEs to the base station.

[0063] Figure 5 is illustrated such as system 100( Figure 1 ) or system 400( Figure 4Diagram of a non - limiting example of multi - layer transmission 500 in a wireless communication system

[0064] For example, in one aspect, a non - limiting example with six layers and four resources is described. Each layer uses two of the four available resources, as described below with reference to Figure 6 the same. That is, each layer uses two resources (out of the four available resources) for transmission and does not send any data on the other two unused resources. The resources used by a layer can be referred to as non - zero resources, and the resources not used by the layer can be referred to as zero resources. Additionally, in one aspect, the resources can be orthogonal to each other (e.g., orthogonal resources) and can be the RBs as described above with reference to Figure 2A the same. Additionally, Figure 5 the first and second resources in Figure 6 represent the used (e.g., non - zero) resources on a layer and can include any two of the four resources (e.g., any two of resources R1, R2, R3, and / or R4, as described below with reference to Figure 6 the same).

[0065] At each layer, an FEC encoder (e.g., FEC encoders 531, 532, 533, 534, 535, and / or 536) converts the data available for transmission on each layer into binary data bits. For example, the data available for transmission at layer C1 can be converted into binary data bits 0 or 1 for each of the resources (e.g., for the first and second resources). For example, in one aspect, FEC encoder 531 can output binary data bits (0, 0) at layer C1 to the two resources used by layer C1. These two bits are for the two resources used at layer C1 (e.g., the two non - zero resources at layer C1). In another or alternative aspect, FEC encoder 531 can output binary data bits (0, 1), (1, 0), or (1, 1) at layer C1 based on the data available for transmission at the first and second resources of layer C1. At layers C2 - C6, a similar process can be used to convert the data available for transmission at layers C2 - C6 into binary data bits. For example, in another or alternative aspect, FEC encoder 536 can output binary data bits (0, 0), (0, 1), (1, 0), and / or (1, 1) corresponding to the two resources used by layer C6 at layer C6. Although the above examples are described in the context of two bits, the present disclosure is not limited to two bits per layer. For example, for each layer, four bits can be used, such as (0, 0, 0, 0), (0, 0, 0, 1), (0, 0, 1, 0), etc.

[0066] In one aspect, the output of the FEC encoder is mapped to codewords. For example, in one aspect, the output of the FEC encoder 531 (e.g., (0,0)) can be mapped to 3 and -1. The mapping of binary data bits to codewords in a signal constellation (also referred to as a "codebook") is based at least on maximizing the distance between codewords of different layers, particularly the distance between adjacent codewords. For example, as described below with reference to Figure 7 the binary data bits (0,0) associated with layer C1 are mapped to (3, -1), the binary data bits (0,1) associated with layer C1 are mapped to (1, 3), the binary data bits (1,0) associated with layer C1 are mapped to (-1, -3), and the binary data bits (1,1) associated with layer C1 are mapped to (-3, 1). For example, by mapping the binary data bits (0,0) and (0,1) to (3, -1) and (1,3), the binary data bits (0,0) and (0,1) are separated by the maximum possible distance in the signal constellation. This allows the receiver (e.g., the receiver at UE 104 or base station 102) to correctly detect the transmitted bit pairs.

[0067] Additionally, each of layers C2 - C6 can have its own codebook such that the mapping of the binary bits of the layer maximizes the distance between the codewords between the layers. Although the mapping of resources at layer C1 (e.g., the used / non-zero resources) is described above, a similar mapping process can be designed or implemented for the resources at layers C2 - C6. For example, the binary data bits of layers 2 - 6 associated with the first and second resources can be mapped as follows:

[0068] (b21,b22)→(c21,c22)

[0069] (b31,b32)→(c31,c32)

[0070] (b41,b42)→(c41,c42)

[0071] (b51,b52)→(c51,c52)

[0072] (b61,b62)→(c61,c62)

[0073] In addition, in one aspect, before transmission, the codewords of each layer in the layer may be combined into a combined codeword, for example. For example, in one aspect, the codewords associated with all layers of a resource are combined via a linear combiner 570 to generate a combined codeword for the resource. For example, the codewords for resource "R1", such as codewords 3, c21, and c31, may be combined to generate a combined codeword "A" to be transmitted on resource R1. In addition, the codewords for resource "R2" (such as codewords -1, c42, and c52) may be combined to generate a combined codeword "B" to be transmitted on resource R2. As a result, at the receiving side (e.g., at UE 104 or base station 102), the received signal will be a linear combination of all layers on a specific resource. Similarly, when the receiver receives a multi-layer transmission 432, the receiver searches for combinations of all possible signals for decoding at the receiver. As described above, data is transmitted in multiple layers from the base station. In another aspect, the layers may be assigned to one UE, two UEs, three UEs, etc. For example, all layers (i.e., six layers) may be assigned to UE 104 to increase the throughput at the UE.

[0074] In addition, the signal constellation / codebook mechanism / process described above is from the perspective of the base station, and the same / similar mechanism / process may be defined / implemented at the UE for transmission on the uplink at the base station.

[0075] Figure 6 is an illustrative example of the resource allocation 600 between layers in a wireless communication system such as system 100( Figure 1 ) or system 400( Figure 4 ).

[0076] For example, in one aspect, the number of resources may be defined as "M", and the number of layers may be defined as "N", where the value of M is less than N. That is, the number of resources is less than the number of layers (e.g., UEs). This may result in resources being shared by layers (e.g., non-dedicated resources). Data may be transmitted from the base station 102 to one or more UEs 104 on the downlink, or from one or more UEs 104 to the base station 102 on the uplink. Although described in the context of four resources and six layers Figure 6 , the process / mechanism may be applied to any other number of resources and / or layers.

[0077] In one aspect, the resources may be represented by rows - R1(610), R2(620), R3(630), and R4(640), and the layers may be represented by columns - C1(615), C2(625), C3(635), C4(645), C5(655), and C6(655). Each of the resources may include one or more RBs, which are referred to aboveFigure 2A has been described in detail. Additionally, as referenced above Figure 4-5 as described, each of the layers in the layer can use two resources (out of the total four available resources) for transmission. That is, for each layer, data is sent only on two of the (four resources), and no data is sent on the other two resources. In an example aspect, the resources used by the layer can be referred to as "used" or "non-zero" resources, and the resources not used by the layer can be referred to as "unused" or "zero" resources.

[0078] In one aspect, the four resources can be allocated or assigned among the six layers, where each of the layers uses two resources for transmission, as Figure 6 shown. For example, layer C1 (615) can use resources R1 (610) and R2 (620), layer C2 (625) can use resources R1 (610) and R3 (630), layer C3 (635) can use resources R1 (610) and R4 (640), layer C4 (645) can use resources R2 (620) and R3 (630), layer C5 (655) can use resources R2 (620) and R4 (640), and layer C6 (665) can use resources R3 (630) and R4 (640).

[0079] Additionally, for each of the layers, no transmission occurs on each of the other two resources not used by the layer. For example, for layer C1 (615), no transmission occurs on resources R3 (630) and R4 (640); for layer C2, no transmission occurs for resources R2 and R4; for layer C3, no transmission is sent for resources R2 and R3; for layer C4, no transmission occurs for resources R1 and R4; for layer C5; no transmission occurs for resources R1 and R3, and for layer C6, no transmission occurs for resources R1 and R1.

[0080] In another aspect, a pair of layers can be configured as an orthogonal pair. For example, layer C1 (615) and layer C6 (665) can be configured as an orthogonal pair, layer C2 (625) and layer C5 (655) can be configured as another orthogonal pair, and / or layer C3 (635) and layer C4 (645) can be configured as another orthogonal pair. That is, the six layers are configured as three orthogonal pairs. In one aspect, if a pair of layers use different resources for transmission, then the pair of layers can be configured as an orthogonal pair. For example, layer C1 (615) uses resources R1 (610) and R2 (620) for transmission, and layer C6 (665) uses resources R3 (630) and R4 (640) for transmission. Since the resources used by layer C1 and layer C6 are different resources, layer C1 and layer C6 can be configured or defined as an orthogonal pair. In addition, layer C2 uses resources R1 and R3 for transmission, and layer C5 uses resources R3 and R4 for transmission. Since the resources used by layer C2 and layer C5 are different, layer C2 and layer C5 are defined as an orthogonal pair. In addition, layer C3 uses resources R1 and R4 for transmission, and layer C4 uses resources R2 and R3 for transmission. Since the resources used by layer C3 and layer C4 are different resources (in other words, different orthogonal resources), layer C1 and layer C6 are defined as an orthogonal pair

[0081] In a further aspect, the layers can be rotated to increase the distance between the codewords of each of the layers. For example, in one aspect, layer C2 (625) can be rotated 60° away from layer C1 (615) to increase the distance between the codewords in, for example, two dimensions from layer C1. In addition, layer C3 (635) can be rotated 120° away from layer C1 to increase the distance in, for example, two dimensions from layer C1. That is, layer C3 is rotated another 60° away from layer C2 to increase the distance from layer C2. Since the codewords are separated, this can increase the decoding success rate at the receiver when the receiver decodes the data received at the receiver. In a further or alternative aspect, layer C2 (625) can be rotated 45° away from layer C1 (615) to increase the distance between the codewords in, for example, two dimensions from layer C1. In addition, layer C3 (635) can be rotated 90° away from layer C1 to increase the distance in, for example, two dimensions from layer C1. That is, layer C3 is rotated another 45° away from layer C2 to increase the distance from C2. When the layers are rotated differently, the performance at the receiving end can also be different. For example, the performance obtained by rotating the layers 60° / 120° is better than the performance obtained by rotating the layers 45° / 90°, as Figure 9A shown in 9B, 10, 11B, and 11C.

[0082] Figure 7 is illustrated in, for example, system 100( Figure 1) or system 400( Figure 4 ) of a wireless communication system mapping a set of binary data bits of a layer to a codeword, a non - restrictive example of a diagram.

[0083] For example, in one aspect, the binary data bits associated with each resource of the resources of the layer are mapped to codewords in a signal constellation (e.g., a codebook), where each layer among the layers may have its own codebook. For example, referring to layer C1, the binary data bits "0" and "0" (represented by Figure 7 (0,0) in

[0084] Figure 8 associated with resources R1 and R2) may be mapped to "3" and "-1", respectively. Additionally, referring to layer C1, the binary data bits (0,1) associated with resources R1 and R2 may be mapped to "1" and "3", respectively, the binary data bits (1,0) associated with resources R1 and R2 may be mapped to "-1" and "-3", respectively; and the binary data bits (1,1) associated with resources R1 and R2 may be mapped to "-3" and "1", respectively. For example, in one aspect, mapping resources (e.g., R1 and R2 of layer C1) to codewords 3 and -1 is performed in the following manner: the distance between the codewords of the (signal constellation or codebook) is maximized to increase the likelihood of successful decoding at the receiver. Although the mapping of binary data bits to codewords in a signal constellation has been described above in the context of one layer (e.g., layer C1), a similar mapping process may be implemented for each of the other layers. Figure 1 ) or system 400( Figure 4 ) of a wireless communication system mapping a set of binary data bits to a codeword, a non - restrictive example of a diagram. For example, Figure 8 shows mapping a set of binary data bits associated with layer C1 to codewords in the signal constellation (e.g., codebook) of layer C1.

[0085] Figure 9A -B illustrates non - restrictive examples of codebook designs 900 and 950 in a wireless communication system such as system 100( Figure 1 ) or system 400( Figure 4 ). For example, Figure 9A illustrates a codebook design for layer C1, where for layer C2, the signal constellation is rotated by 60°, and for layer C3, the signal constellation is rotated by 120° (referred to as "design 1"). Additionally, Figure 9B illustrates another codebook design for layer C1, where for layer C2, the signal constellation is rotated by 45°, and for layer C3, the signal constellation is rotated by 90° (referred to as "design 2").

[0086] Figure 10 is a diagram illustrating the codebook performance with six layers, 4 resources (or symbols) per layer, and 2 bits used per layer. As Figure 10 shown, the performance of Design 1 (i.e., rotated by 60° / 120°) is relatively better than that of Design 2 (i.e., rotated by 45° / 90°), and both are relatively better than the known codebook designs.

[0087] Figure 11A -C illustrates the codebook performance using the known codebook design ( Figure 11A ). Haitong - Please clarify the meaning of "known codebook design" and provide an example if possible.

[0088] Figure 12A -B illustrates the codebook performance using the known codebook design and Design 1 (i.e., rotated by 60° / 120°) and Design 2 (i.e., rotated by 45° / 90°) according to aspects of the present disclosure.

[0089] Figure 13 is a flowchart of aspects of multi-layer transmission that can be performed by the multi-layer transmission component 420 of Figure 4 . Referring to Figure 13 , for example, a base station such as base station 102 and / or UE 104 ( Figure 1 and Figure 4 ) may include one or more processors for performing aspects of the method 1300 for multi-layer transmission. Although, for the purpose of simplifying the description, the method is shown and described as a series of actions, it should be understood and appreciated that the method is not limited to the order of the actions, because according to one or more embodiments, some actions may occur in a different order than shown and described herein and / or may occur simultaneously with other actions shown and described herein. For example, it should be understood that the method may alternatively be represented as a series of interrelated states or events such as in a state diagram. In addition, not all of the shown actions may be required to implement the method according to one or more features described herein.

[0090] In one aspect, at block 1310, method 1300 may include, at a transmitter, generating a set of binary data bits for resources of each of a plurality of layers. For example, in one aspect, base station 102 and / or multi-layer transmission component 420 may generate a set of binary data bits for resources of all six layers (e.g., (0,0) for layer C1, etc.). In one aspect, binary data generation component 422 may generate a set of binary data bits for resources of each of the plurality of layers. In another or alternative aspect, generating the set of binary data bits may be performed by an FEC encoder (e.g., FEC encoder 531 for layer C1) / at an FEC encoder. In another or alternative aspect, UE 104 and / or multi-layer transmission component 420 may generate a set of binary data bits for resources of all six layers (e.g., (0,0) for layer C1, etc.).

[0091] In one aspect, at block 1320, method 1300 may include mapping the set of binary data bits of each of the plurality of layers to a corresponding codeword in a signal constellation, where the mapping is at least based on maximizing the distance between the codewords within each of the plurality of layers. For example, in one aspect, base station 102 and / or multi-layer transmission component 420 may map each of the set of binary data bits (e.g., (0,0)) to a corresponding codeword in a signal constellation (e.g., (3, -1)), where the mapping is at least based on maximizing the distance between the codewords within each of the plurality of layers (e.g., the distance between 3 and -1 is maximized). In one aspect, mapping component 424 may perform the mapping. In another or alternative aspect, the mapping may be performed by / at a codebook (e.g., codebook 551 for layer C1). In another or alternative aspect, UE 104 and / or multi-layer transmission component 420 may map the set of binary data bits of each of the plurality of layers to a corresponding codeword in a signal constellation, where the mapping is at least based on maximizing the distance between the codewords within each of the plurality of layers.

[0092] In one aspect, at block 1330, method 1300 may include combining the codewords at the transmitter. For example, in one aspect, base station 102 and / or multi-layer transmission component 420 may combine the codewords at the transmitter before transmission. In one aspect, combining component 426 may perform the combining. In another or alternative aspect, the combining may be performed by / at a linear combiner 570 / linear combiner 57. In another or alternative aspect, UE 104 and / or multi-layer transmission component 420 may combine the codewords at the transmitter.

[0093] In one aspect, at block 1340, method 1300 may include transmitting the combined codewords from the transmitter to a receiver in the wireless network. For example, in one aspect, in one aspect, base station 102 and / or multi-layer transmission component 420 may transmit the combined codewords 432. In one aspect, transmission component 428 may perform the transmission. In additional or alternative aspects, UE 104 and / or multi-layer transmission component 420 may transmit the combined codewords to a receiver in the wireless network.

[0094] In an example aspect, base station 102 may be the transmitter, and UE 104 may be, for example, a receiver in a downlink SCMA transmission from base station 102 to UE 104. In another example aspect, UE 104 may be the transmitter, and base station 102 may be, for example, a receiver in an uplink SCMA transmission from UE 104 to base station 102.

[0095] Figure 14 FIG. 1400 is a conceptual data flow diagram illustrating the data flow between different units / components in an exemplary apparatus 1402 including a multi-layer transmission component 1420. The multi-layer transmission component 1420 may be the same as or similar to the multi-layer transmission component 420 for multi-layer transmission of Figure 4 . The apparatus may be a base station, which may be the base station 102 of Figure 1 or 4, and / or a UE, which may be the UE 104 of Figure 1 or Figure 4 . The apparatus includes: a binary data generation component 1406 for generating a set of binary data bits for resources of each layer in the layer; a mapping component 1408 for mapping each of the set of binary data bits to a corresponding codeword in a signal constellation; a combining component 1410 for combining the codewords; a transmitting component 1412 for transmitting the combined codewords; and a receiving component 1404 for receiving one or more signals (e.g., the combined codewords) from UE 1450.

[0096] The apparatus may include additional components for performing each block of the algorithms in the above-mentioned flowchart of Figure 13 . Similarly, Figure 13 each block in the above-mentioned flowchart of

[0097] Figure 15 may be performed by a component, and the apparatus may include one or more of these components. The components may be one or more hardware components specifically configured to perform the process / algorithm, implemented by a processor configured to perform the process / algorithm, stored in a computer-readable medium for implementation by the processor, or some combination thereof. Figure 14FIG. 1500 is an example of a hardware implementation of an apparatus 1502' of a processing system 1514 of a multi-layer transmission component 1420, which may be the same as or similar to the multi-layer transmission component 420 for multi-layer transmission in ( Figure 4 ). The processing system 1514 may be implemented using a bus architecture, typically represented by a bus 1524. Depending on the specific application and overall design constraints of the processing system 1514, the bus 1524 may include any number of interconnecting buses and bridges. The bus 1524 links together various circuits, including one or more processors and / or hardware components represented by a processor 1504, components 1404, 1406, 1408, 1410, and 1412, and a computer-readable medium / memory 1506. The bus 1524 may also link various other circuits, such as a timing source, peripherals, a voltage regulator, and a power management circuit, which are well known in the art and will not be described further herein.

[0098] The processing system 1514 may be coupled to a transceiver 1510. The transceiver 1510 is coupled to one or more antennas 1520. The transceiver 1510 provides a unit for communicating with various other devices via a transmission medium. The transceiver 1510 receives signals from one or more antennas 1520, extracts information from the received signals, and provides the extracted information to the processing system 1514, specifically to a receiving component 1404. In addition, the transceiver 1510 receives information from the processing system 1514, specifically from a transmitting component 1412, and based on the received information, generates signals to be applied to one or more antennas 1520. The processing system 1514 includes a processor 1504 coupled to a computer-readable medium / memory 1506. The processor 1504 is responsible for general processing, including executing software stored on the computer-readable medium / memory 1506. When executed by the processor 1504, the software causes the processing system 1514 to perform the various functions described above for any particular device. The computer-readable medium / memory 1506 may also be used to store data manipulated by the processor 1504 when the software is executed. The processing system 1514 further includes at least one of components 1404, 1406, 1408, 1410, and 1412. The components may be software components running in the processor 1504, may reside / store in the computer-readable medium / memory 1506, one or more hardware components coupled to the processor 1504, or some combination thereof.

[0099] In one configuration, an apparatus 1502 / 1502' for wireless communication includes units for generating a set of binary data bits for resources of each of the layers; units for mapping each of the set of binary data bits to a corresponding codeword in a signal constellation, wherein the mapping of each of the set of binary data bits is at least based on maximizing the distance between codewords within each of the layers; units for combining the codewords; and units for transmitting the combined codewords. The above units may be one or more of the above components of apparatus 1502 and / or the processing system 1514 of apparatus 1502' configured to perform the functions recited by the above units. As described above, the processing system 1514 may include a TX processor 316, an RX processor 370, and a controller / processor 375. Also, in one configuration, the above units may be the TX processor 316, the RX processor 370, and the controller / processor 375 configured to perform the functions recited by the above units. On the other hand, the processing system 1514 may include a TX processor 368, an RX processor 356, and a controller / processor 359. Also, in another configuration, the above units may be the TX processor 368, the RX processor 356, and the controller / processor 359 configured to perform the functions recited by the units.

[0100] It is to be understood that the specific order or hierarchy of the blocks in the disclosed process / flowchart is an illustration of an exemplary scenario. It is understood that based on design preferences, the specific order or hierarchy of the blocks in the process / flowchart may be rearranged. Additionally, some blocks may be combined or omitted. The appended method claims present the elements in the blocks in a sample order, but are not meant to be limited to the specific order or hierarchy presented.

[0101] The foregoing 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 apparent to those skilled in the art, and the general principles defined herein can be applied to other aspects. Thus, the claims are not intended to be limited to the aspects shown herein, but are to be accorded the full scope consistent with the language of the claims, where the reference to an element in the singular does not mean "only one" unless explicitly so stated, but rather "one or more". The term "exemplary" is used herein to mean "serving as an example, instance, or illustration". Any aspect described herein as "exemplary" need not be construed as preferred or superior to other aspects. Unless otherwise specified, the term "some" means 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 "any combination of A, B, C, or any 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 "any combination of A, B, C, or any thereof" can be only A, only B, only C, A and B, A and C, B and C, or A and B and C, where any such combination can include one or more members of A, B, or C. All structural and functional equivalents of the elements of the various aspects described throughout this disclosure that are known or later become known to those of ordinary skill in the art are hereby expressly incorporated 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", etc. are not intended to be substitutes for "unit". Likewise, no claim element is to be construed as a unit plus function unless the element is expressly recited using the phrase "means for...".

Claims

1. A method for multi-layer transmission in a wireless network, comprising: Generating data for transmission for each of a plurality of layers; Converting the data for each layer into a corresponding data bit group for the corresponding layer, each data bit of the data bit group being for a corresponding non-zero resource for the corresponding layer among a plurality of resources, the plurality of layers being configured as a plurality of orthogonal layer pairs; Mapping the data bit group for each layer to a corresponding codeword associated with a signal constellation, the mapping including: mapping the data bit group of the at least one corresponding layer based on increasing the distance from another data bit group within the at least one corresponding layer; Rotating the signal constellation 45 degrees with respect to a second orthogonal layer pair among the plurality of orthogonal layer pairs and 90 degrees with respect to a third orthogonal layer pair among the plurality of orthogonal layer pairs across a first orthogonal layer pair among the plurality of orthogonal layer pairs, or rotating 60 degrees with respect to the second orthogonal layer pair among the plurality of orthogonal layer pairs and 120 degrees with respect to the third orthogonal layer pair among the plurality of orthogonal layer pairs; Linearly combining the codewords for the plurality of layers for each resource among the plurality of resources into a combined codeword for the corresponding resource; and Transmitting the combined codewords for the plurality of resources.

2. The method according to claim 1, wherein, The multi-layer transmission is sparse code multiple access (SCMA) transmission.

3. The method according to claim 1, wherein The plurality of resources include orthogonal resources, and the method further includes: Creating the orthogonal resources using tones in orthogonal frequency division multiple access (OFDMA), orthogonal codes in code division multiple access, time in time division multiplexing (TDM), or different spatial characteristics.

4. The method according to claim 1, wherein, The multi-layer transmission includes a first number of resources and a second number of layers, and wherein the first number of resources is less than the second number of layers.

5. The method according to claim 4, wherein, The first number of resources is four, the second number of layers is six, and the number of resources used by each of the layers is two.

6. The method according to claim 5, wherein The six layers are configured as three orthogonal layer pairs.

7. The method according to claim 1, wherein Rotating the signal constellation across the first orthogonal layer pair among the plurality of orthogonal layer pairs increases the distance between at least one codeword in at least one layer of one orthogonal layer pair and at least another codeword in at least another layer of another orthogonal layer pair among the plurality of orthogonal layer pairs in two dimensions.

8. The method according to claim 7, wherein, At least one orthogonal layer pair of the plurality of orthogonal layer pairs is obtained by rotating the signal constellation by a degree.

9. The method according to claim 7, wherein The increasing the distance between at least one codeword in at least one layer of one orthogonal layer pair and at least another codeword in at least another layer of another orthogonal layer pair among the plurality of orthogonal layer pairs in two dimensions includes: Maximizing the distance between the codeword for the at least one corresponding layer for the plurality of layers in the signal constellation and the codeword for at least one other corresponding layer for the plurality of layers.

10. An apparatus for multi-layer transmission in a wireless network, comprising: A unit for generating data for transmission for each of a plurality of layers; A unit for converting the data for each layer into a corresponding data bit group for the corresponding layer, each data bit of the data bit group being for a corresponding non-zero resource for the corresponding layer among a plurality of resources, the plurality of layers being configured as a plurality of orthogonal layer pairs; A unit for mapping the data bit group for each layer to a corresponding codeword associated with a signal constellation, the mapping including mapping the data bit group of the at least one corresponding layer based on increasing the distance from another data bit group within the at least one corresponding layer; A unit for rotating the signal constellation by 45 degrees with respect to a first orthogonal layer pair among the plurality of orthogonal layer pairs and by 90 degrees with respect to a third orthogonal layer pair among the plurality of orthogonal layer pairs, or rotating by 60 degrees with respect to a second orthogonal layer pair among the plurality of orthogonal layer pairs and by 120 degrees with respect to a third orthogonal layer pair among the plurality of orthogonal layer pairs; A unit for linearly combining the codewords for the plurality of layers for each resource of the plurality of resources into a combined codeword for the corresponding resource; And A unit for transmitting the combined codewords for the plurality of resources.

11. The apparatus according to claim 10, wherein, The multi-layer transmission is sparse code multiple access (SCMA) transmission.

12. The apparatus according to claim 10, wherein, The plurality of resources include orthogonal resources, and further include: A unit for creating the orthogonal resources using tones in orthogonal frequency division multiple access (OFDMA), orthogonal codes in code division multiple access, time in time division multiplexing (TDM), or different spatial characteristics.

13. The device according to claim 10, wherein, The multi-layer transmission includes a first number of resources and a second number of layers, and wherein the first number of resources is less than the second number of layers.

14. The apparatus according to claim 13, wherein, The first number of resources is four, the second number of layers is six, and the number of resources used by each layer among the layers is two.

15. The apparatus according to claim 14, wherein, The six layers are configured as three orthogonal layer pairs.

16. The device according to claim 10, wherein, The unit for rotating the signal constellation across the first orthogonal layer pair among the plurality of orthogonal layer pairs is configured to increase the distance between at least one codeword in at least one layer of one orthogonal layer pair in two dimensions and at least another codeword in at least another layer of another orthogonal layer pair among the plurality of orthogonal layer pairs.

17. The apparatus according to claim 16, wherein, At least one orthogonal layer pair of the plurality of orthogonal layer pairs is obtained by rotating the signal constellation by a number of degrees.

18. An apparatus for multi-layer transmission in a wireless network, including: A memory; And At least one processor coupled to the memory and configured to: Generate data for transmission for each of a plurality of layers; Convert the data for each layer into a corresponding data bit group for the corresponding layer: Each data bit of the data bit group is for a corresponding non-zero resource for the corresponding layer among a plurality of resources, the plurality of layers being configured as a plurality of orthogonal layer pairs; Map the data bit group for each layer to a corresponding codeword associated with a signal constellation, the mapping including mapping the data bit group of the at least one corresponding layer based on increasing the distance from another data bit group within the at least one corresponding layer; Rotate the signal constellation by 45 degrees for a first pair of orthogonal layers among the plurality of orthogonal layer pairs with respect to a second pair of orthogonal layers among the plurality of orthogonal layer pairs and by 90 degrees with respect to a third pair of orthogonal layers among the plurality of orthogonal layer pairs, or rotate by 60 degrees with respect to the second pair of orthogonal layers among the plurality of orthogonal layer pairs and by 120 degrees with respect to the third pair of orthogonal layers among the plurality of orthogonal layer pairs; Linearly combine the codewords for the plurality of layers for each resource of the plurality of resources into a combined codeword for the corresponding resource; And Transmit the combined codewords for the plurality of resources.

19. The apparatus according to claim 18, wherein, The multi-layer transmission is a sparse code multiple access (SCMA) transmission.

20. The apparatus according to claim 18, wherein, The plurality of resources include orthogonal resources, and wherein at least one processor is further configured to: Create the orthogonal resources using tones in orthogonal frequency division multiple access (OFDMA), orthogonal codes in code division multiple access, time in time division multiplexing (TDM), or different spatial characteristics.

21. The device according to claim 18, wherein, The multi-layer transmission includes a first number of resources and a second number of layers, and wherein the first number of resources is less than the second number of layers.

22. The apparatus according to claim 21, wherein, The first number of resources is four, the second number of layers is six, and the number of resources used for each of the layers is two.

23. The device according to claim 22, wherein, The six layers are configured as three pairs of orthogonal layers.

24. The apparatus according to claim 18, wherein Rotating the signal constellation across the first pair of orthogonal layers among the plurality of orthogonal layer pairs increases the distance between at least one codeword in at least one layer of one of the plurality of orthogonal layer pairs in two dimensions and at least another codeword in at least another layer of another of the plurality of orthogonal layer pairs.

25. The apparatus according to claim 24, wherein, At least one of the plurality of pairs of orthogonal layers is obtained by rotating the signal constellation by a number of degrees.

26. A non-transitory computer-readable medium storing computer-executable code for multi-layer transmission in a wireless network, including code for: Generating data for transmission for each of a plurality of layers; Converting the data for each layer into a corresponding group of data bits for the corresponding layer, each data bit of the group of data bits being for a corresponding non-zero resource of a plurality of resources for the corresponding layer, the plurality of layers being configured as a plurality of pairs of orthogonal layers; Mapping the group of data bits for each layer to a corresponding codeword associated with a signal constellation, the mapping including: mapping the group of data bits for the at least one corresponding layer based on increasing the distance from another group of data bits within the at least one corresponding layer; Rotate the signal constellation by 45 degrees for a first pair of orthogonal layers among the plurality of orthogonal layer pairs with respect to a second pair of orthogonal layers among the plurality of orthogonal layer pairs and by 90 degrees with respect to a third pair of orthogonal layers among the plurality of orthogonal layer pairs, or rotate by 60 degrees with respect to the second pair of orthogonal layers among the plurality of orthogonal layer pairs and by 120 degrees with respect to the third pair of orthogonal layers among the plurality of orthogonal layer pairs; Linearly combine the codewords for the plurality of layers for each resource of the plurality of resources into a combined codeword for the corresponding resource; and Transmit the combined codewords for the plurality of resources.

27. The non-transitory computer-readable medium according to claim 26, wherein, The multi-layer transmission is sparse code multiple access (SCMA) transmission.

28. The non-transitory computer-readable medium according to claim 26, wherein, The plurality of resources includes orthogonal resources and also includes codes for the following operations: Creating the orthogonal resources using tones in orthogonal frequency division multiple access (OFDMA), orthogonal codes in code division multiple access, time in time division multiplexing (TDM), or different spatial characteristics.

29. The non-transitory computer-readable medium according to claim 26, wherein, The multi-layer transmission includes a first number of resources and a second number of layers, and wherein the first number of resources is less than the second number of layers.

30. The non-transitory computer-readable medium according to claim 29, wherein, The first number of resources is four, the second number of layers is six, and the number of resources used by each of the layers is two.

31. The non-transitory computer-readable medium according to claim 30, wherein, The six layers are configured as three orthogonal layer pairs.

32. The non-transitory computer-readable medium according to claim 26, wherein, Rotating the signal constellation across the first orthogonal layer pair among the plurality of orthogonal layer pairs increases the distance between at least one codeword in at least one layer of one orthogonal layer pair in two dimensions and at least another codeword in at least another layer of another orthogonal layer pair among the plurality of orthogonal layer pairs.

33. The non-transitory computer-readable medium according to claim 32, wherein, At least one orthogonal layer pair of the plurality of orthogonal layer pairs is obtained by rotating the signal constellation by a number of degrees.

Images