WO2018027912A1

WO2018027912A1 - Sparse code multiple access communication

Info

Publication number: WO2018027912A1
Application number: PCT/CN2016/094898
Authority: WO
Inventors: Haipeng Lei; Chenxi Zhu; Yuechao GUO
Original assignee: Lenovo Innovations Limited (Hong Kong)
Priority date: 2016-08-12
Filing date: 2016-08-12
Publication date: 2018-02-15

Abstract

Apparatuses, methods, and systems are disclosed for sparse code multiple access communication. One apparatus includes a transmitter that transmits a first signal to a first device for indicating a first resource. The first resource is used by the first device to transmit a first sequence, and the first sequence corresponds to a first sparse code multiple access codeword. The apparatus also includes a receiver that receives the first sequence on the first resource, and receives first data on a first resource set determined based on the first sparse code multiple access codeword.

Description

SPARSE CODE MULTIPLE ACCESS COMMUNICATION

FIELD

The subject matter disclosed herein relates generally to wireless communications and more particularly relates to sparse code multiple access communication.

BACKGROUND

The following abbreviations are herewith defined, at least some of which are referred to within the following description: Third Generation Partnership Project ( “3GPP” ) , Positive-Acknowledgment ( “ACK” ) , Binary Phase Shift Keying ( “BPSK” ) , Clear Channel Assessment ( “CCA” ) , Cyclic Prefix ( “CP” ) , Channel State Information ( “CSI” ) , Code Division Multiple Access ( “CDMA” ) , Common Search Space ( “CSS” ) , Downlink Control Information (“DCI” ) , Downlink ( “DL” ) , Downlink Pilot Time Slot ( “DwPTS” ) , Enhanced Clear Channel Assessment ( “eCCA” ) , Evolved Node B ( “eNB” ) , European Telecommunications Standards Institute ( “ETSI” ) , Frame Based Equipment ( “FBE” ) , Frequency Division Duplex ( “FDD” ) , Frequency Division Multiple Access ( “FDMA” ) , Guard Period ( “GP” ) , Hybrid Automatic Repeat Request ( “HARQ” ) , Licensed Assisted Access ( “LAA” ) , Load Based Equipment (“LBE” ) , Listen-Before-Talk ( “LBT” ) , Long Term Evolution ( “LTE” ) , Machine Type Communication ( “MTC” ) , Multiple Input Multiple Output ( “MIMO” ) , Multi User Shared Access ( “MUSA” ) , Negative-Acknowledgment ( “NACK” ) or ( “NAK” ) , Orthogonal Frequency Division Multiplexing ( “OFDM” ) , Primary Cell ( “PCell” ) , Physical Broadcast Channel (“PBCH” ) , Physical Downlink Control Channel ( “PDCCH” ) , Physical Downlink Shared Channel ( “PDSCH” ) , Pattern Division Multiple Access ( “PDMA” ) , Physical Hybrid ARQ Indicator Channel ( “PHICH” ) , Physical Random Access Channel ( “PRACH” ) , Physical Resource Block ( “PRB” ) , Physical Uplink Control Channel ( “PUCCH” ) , Physical Uplink Shared Channel ( “PUSCH” ) , Quality of Service ( “QoS” ) , Quadrature Phase Shift Keying ( “QPSK” ) , Radio Resource Control ( “RRC” ) , Random Access Procedure ( “RACH” ) , Resource Spread Multiple Access ( “RSMA” ) , Round Trip Time ( “RTT” ) , Receive ( “RX” ) , Sparse Code Multiple Access ( “SCMA” ) , Scheduling Request ( “SR” ) , Single Carrier Frequency Division Multiple Access ( “SC-FDMA” ) , Secondary Cell ( “SCell” ) , Shared Channel ( “SCH” ) , Signal-to-Interference-Plus-Noise Ratio ( “SINR” ) , System Information Block ( “SIB” ) , Transport Block (“TB” ) , Transport Block Size ( “TBS” ) , Time-Division Duplex ( “TDD” ) , Time Division Multiplex ( “TDM” ) , Transmission Time Interval ( “TTI” ) , Transmit ( “TX” ) , Uplink Control Information ( “UCI” ) , User Entity/Equipment ( “Mobile Terminal” ) ( “UE” ) , Uplink ( “UL” ) , Universal Mobile Telecommunications System ( “UMTS” ) , Uplink Pilot Time Slot ( “UpPTS” ) , Ultra-reliable and Low-latency Communications ( “URLLC” ) , and Worldwide Interoperability for Microwave Access ( “WiMAX” ) . As used herein, “HARQ-ACK” may represent collectively the Positive Acknowledge ( “ACK” ) and the Negative Acknowledge ( “NAK” ) . ACK means that a TB is correctly received while NAK means a TB is erroneously received.

In certain wireless communications networks, to avoid resource collision in uplink communication, the networks adopt orthogonal multiple access ( “OMA” ) . The networks may also use scheduling-based uplink transmission so that the orthogonal resources are assigned for different UEs. Moreover, any uplink communication (e.g., except PRACH) may be scheduled and/or controlled by an eNB. As compared to OMA, non-orthogonal multiple access (“NOMA” ) may support signal superposition in an orthogonal resource. Accordingly, NOMA may enhance spectrum utilization efficiency, such as in cases of overloaded transmission. Moreover, since NOMA may separate superposed signals at the receiver by using more advanced algorithms, NOMA may support reliable and low latency grant-free transmission. Such transmission may be used for massive MTC and/or URLLC.

In some configurations, there may be no clear difference between autonomous, grant-free, and/or contention based UL transmission. In certain configurations, contention based UL transmission may include autonomous, grant-free, and/or grant-less transmission.

SCMA is one possible NOMA technique. With SCMA, a transmitter does not transmit using all available resources. Among many resources, a UE may select a subset of resources for its transmission. The resources used for a single transmission (either by a transmitter, or transmission of a layer) occupies only a small fraction of all the available resources. In some configurations, the resources used by a transmission are determined by a SCMA codeword, which may be a vector indicating the used resources. In certain configurations, there may be a large number of SCMA codewords in a codebook. Moreover, a resource may be included in multiple codewords (therefore it may be used by multiple UEs in their transmission) . An eNB may use excessive processing to determine SCMA codewords used by a UE.

BRIEF SUMMARY

Apparatuses for sparse code multiple access communication are disclosed. Methods and systems also perform the functions of the apparatus. In one embodiment, the apparatus includes a transmitter that transmits a first signal to a first device for indicating a first resource. In such an embodiment, the first resource is used by the first device to transmit a first sequence, and the first sequence corresponds to a first sparse code multiple access codeword. The apparatus also includes a receiver that receives the first sequence on the first resource, and receives first data on a first resource set determined based on the first sparse code multiple access codeword.

In one embodiment, the transmitter transmits a second signal to a second device for indicating the first resource. In such an embodiment, the first resource is used by the second device for transmitting a second sequence, and the second sequence corresponds to a second sparse code multiple access codeword. In a further embodiment, the receiver receives the second sequence on the first resource, and receives second data on a second resource set determined based on the second sparse code multiple access codeword. In some embodiments, the first resource set and the second resource set are different. In certain embodiments, the first resource and the first resource set are multiplexed in a time domain.

In some embodiments, the first resource and the first resource set are multiplexed in a frequency domain. In various embodiments, the first resource and the first resource set overlap in both a time domain and a frequency domain. In certain embodiments, the first sequence is a code division multiple access sequence.

A method for sparse code multiple access, in one embodiment, includes transmitting a first signal to a first device for indicating a first resource. In such an embodiment, the first resource is used by the first device to transmit a first sequence, and the first sequence corresponds to a first sparse code multiple access codeword. The method also includes receiving the first sequence on the first resource. The method includes receiving first data on a first resource set determined based on the first sparse code multiple access codeword.

In one embodiment, an apparatus includes a receiver that receives a signal for indicating a resource. In such an embodiment, the resource is used for transmitting a sequence that corresponds to a sparse code multiple access codeword. The apparatus also includes a processor that selects the sequence from a sequence set. In such an embodiment, each sequence of the sequence set corresponds to a respective sparse code multiple access codeword, and generates data based on the sparse code multiple access codeword. The apparatus includes a transmitter that transmits the sequence on the resource, and transmits the data on a resource set determined by the sparse code multiple access codeword.

In one embodiment, the resource and the resource set are multiplexed in a time domain. In a further embodiment, the resource and the resource set are multiplexed in a frequency domain. In some embodiments, the resource and the resource set overlap in both a time domain and a frequency domain. In certain embodiments, the sequence is a code division multiple access sequence.

A method for sparse code multiple access, in one embodiment, includes receiving a signal for indicating a resource. In such an embodiment, the resource is used for transmitting a sequence that corresponds to a sparse code multiple access codeword. The method also includes selecting the sequence from a sequence set. In such an embodiment, each sequence of the sequence set corresponds to a respective sparse code multiple access codeword. The method includes generating data based on the sparse code multiple access codeword. The method also includes transmitting the sequence on the resource. The method includes transmitting the data on a resource set determined by the sparse code multiple access codeword.

BRIEF DESCRIPTION OF THE DRAWINGS

A more particular description of the embodiments briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only some embodiments and are not therefore to be considered to be limiting of scope, the embodiments will be described and explained with additional specificity and detail through the use of the accompanying drawings, in which:

Figure 1 is a schematic block diagram illustrating one embodiment of a wireless communication system for sparse code multiple access communication；

Figure 2 is a schematic block diagram illustrating one embodiment of an apparatus that may be used for sparse code multiple access communication；

Figure 3 is a schematic block diagram illustrating one embodiment of an apparatus that may be used for sparse code multiple access communication；

Figure 4 illustrates one embodiment of communications for sparse code multiple access communication；

Figure 5 illustrates one embodiment of sparse code multiple access resource mapping；

Figure 6 illustrates one embodiment of sparse code multiple access uplink transmissions；

Figure 7 illustrates another embodiment of sparse code multiple access uplink transmissions；

Figure 8 illustrates a further embodiment of sparse code multiple access uplink transmissions；

Figure 9 is a schematic flow chart diagram illustrating one embodiment of a method for sparse code multiple access communication； and

Figure 10 is a schematic flow chart diagram illustrating another embodiment of a method for sparse code multiple access communication.

DETAILED DESCRIPTION

As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or program product. Accordingly, embodiments may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc. ) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit, ” “module” or “system. ” Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, and/or program code, referred hereafter as code. The storage devices may be tangible, non-transitory, and/or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

Certain of the functional units described in this specification may be labeled as modules, in order to more particularly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom very-large-scale integration ( “VLSI” ) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

Modules may also be implemented in code and/or software for execution by various types of processors. An identified module of code may, for instance, include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module need not be physically located together, but may include disparate instructions stored in different locations which, when joined logically together, include the module and achieve the stated purpose for the module.

Indeed, a module of code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different computer readable storage devices. Where a module or portions of a module are implemented in software, the software portions are stored on one or more computer readable storage devices.

Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

More specific examples (a non-exhaustive list) of the storage device would include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory ( “RAM” ) , a read-only memory ( “ROM” ) , an erasable programmable read-only memory ( “EPROM” or Flash memory) , a portable compact disc read-only memory ( “CD-ROM” ) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device.

Code for carrying out operations for embodiments may be any number of lines and may be written in any combination of one or more programming languages including an object oriented programming language such as Python, Ruby, Java, Smalltalk, C++, or the like, and conventional procedural programming languages, such as the "C" programming language, or the like, and/or machine languages such as assembly languages. The code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network ( “LAN” ) or a wide area network (“WAN” ) , or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider) .

Reference throughout this specification to “one embodiment, ” “an embodiment, ” or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases “in one embodiment, ” “in an embodiment, ” and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean “one or more but not all embodiments” unless expressly specified otherwise. The terms “including, ” “comprising, ” “having, ” and variations thereof mean “including but not limited to, ” unless expressly specified otherwise. An enumerated listing of items does not imply that any or all of the items are mutually exclusive, unless expressly specified otherwise. The terms “a, ” “an, ” and “the” also refer to “one or more” unless expressly specified otherwise.

Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. In the following description, numerous specific details are provided, such as examples of programming, software modules, user selections, network transactions, database queries, database structures, hardware modules, hardware circuits, hardware chips, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment.

Aspects of the embodiments are described below with reference to schematic flowchart diagrams and/or schematic block diagrams of methods, apparatuses, systems, and program products according to embodiments. It will be understood that each block of the schematic flowchart diagrams and/or schematic block diagrams, and combinations of blocks in the schematic flowchart diagrams and/or schematic block diagrams, can be implemented by code. These code may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be stored in a storage device that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the storage device produce an article of manufacture including instructions which implement the function/act specified in the schematic flowchart diagrams and/or schematic block diagrams block or blocks.

The code may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the code which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.

The schematic flowchart diagrams and/or schematic block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of apparatuses, systems, methods and program products according to various embodiments. In this regard, each block in the schematic flowchart diagrams and/or schematic block diagrams may represent a module, segment, or portion of code, which includes one or more executable instructions of the code for implementing the specified logical function (s) .

It should also be noted that, in some alternative implementations, the functions noted in the block may occur out of the order noted in the Figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. Other steps and methods may be conceived that are equivalent in function, logic, or effect to one or more blocks, or portions thereof, of the illustrated Figures.

Although various arrow types and line types may be employed in the flowchart and/or block diagrams, they are understood not to limit the scope of the corresponding embodiments. Indeed, some arrows or other connectors may be used to indicate only the logical flow of the depicted embodiment. For instance, an arrow may indicate a waiting or monitoring period of unspecified duration between enumerated steps of the depicted embodiment. It will also be noted that each block of the block diagrams and/or flowchart diagrams, and combinations of blocks in the block diagrams and/or flowchart diagrams, can be implemented by special purpose hardware-based systems that perform the specified functions or acts, or combinations of special purpose hardware and code.

The description of elements in each figure may refer to elements of proceeding figures. Like numbers refer to like elements in all figures, including alternate embodiments of like elements.

Figure 1 depicts an embodiment of a wireless communication system 100 for sparse code multiple access communication. In one embodiment, the wireless communication system 100 includes remote units 102 and base units 104. Even though a specific number of remote units 102 and base units 104 are depicted in Figure 1, one of skill in the art will recognize that any number of remote units 102 and base units 104 may be included in the wireless communication system 100.

In one embodiment, the remote units 102 may include computing devices, such as desktop computers, laptop computers, personal digital assistants ( “PDAs” ) , tablet computers, smart phones, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, modems) , or the like. In some embodiments, the remote units 102 include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the remote units 102 may be referred to as subscriber units, mobiles, mobile stations, users, terminals, mobile terminals, fixed terminals, subscriber stations, UE, user terminals, a device, or by other terminology used in the art. The remote units 102 may communicate directly with one or more of the base units 104 via UL communication signals.

The base units 104 may be distributed over a geographic region. In certain embodiments, a base unit 104 may also be referred to as an access point, an access terminal, a base, a base station, a Node-B, an eNB, a Home Node-B, a relay node, a device, or by any other terminology used in the art. The base units 104 are generally part of a radio access network that includes one or more controllers communicably coupled to one or more corresponding base units 104. The radio access network is generally communicably coupled to one or more core networks, which may be coupled to other networks, like the Internet and public switched telephone networks, among other networks. These and other elements of radio access and core networks are not illustrated but are well known generally by those having ordinary skill in the art.

In one implementation, the wireless communication system 100 is compliant with the LTE of the 3GPP protocol, wherein the base unit 104 transmits using an OFDM modulation scheme on the DL and the remote units 102 transmit on the UL using a SC-FDMA scheme. More generally, however, the wireless communication system 100 may implement some other open or proprietary communication protocol, for example, WiMAX, among other protocols. The present disclosure is not intended to be limited to the implementation of any particular wireless communication system architecture or protocol.

The base units 104 may serve a number of remote units 102 within a serving area, for example, a cell or a cell sector via a wireless communication link. The base units 104 transmit DL communication signals to serve the remote units 102 in the time, frequency, and/or spatial domain.

In one embodiment, a base unit 104 may transmit a first signal to a first device for indicating a first resource. In such an embodiment, the first resource may be used by the first device to transmit a first sequence, and the first sequence may correspond to a first sparse code multiple access codeword. The base unit 104 may receive the first sequence on the first resource. The base unit 104 may also receive first data on a first resource set determined based on the first sparse code multiple access codeword. Accordingly, a base unit 104 may receive sparse code multiple access communication.

In another embodiment, a remote unit 102 may receive a signal for indicating a resource. In such an embodiment, the resource may be used for transmitting a sequence that corresponds to a sparse code multiple access codeword. The remote unit 102 may select the sequence from a sequence set. In such an embodiment, each sequence of the sequence set corresponds to a respective sparse code multiple access codeword. The remote unit 102 may generate data based on the sparse code multiple access codeword. The remote unit 102 may transmit the sequence on the resource. The remote unit 102 may also transmit the data on a resource set determined by the sparse code multiple access codeword. Accordingly, a remote unit 102 may transmit sparse code multiple access communication.

Figure 2 depicts one embodiment of an apparatus 200 that may be used for sparse code multiple access communication. The apparatus 200 includes one embodiment of the remote unit 102. Furthermore, the remote unit 102 may include a processor 202, a memory 204, an input device 206, a display 208, a transmitter 210, and a receiver 212. In some embodiments, the input device 206 and the display 208 are combined into a single device, such as a touchscreen. In certain embodiments, the remote unit 102 may not include any input device 206 and/or display 208. In various embodiments, the remote unit 102 may include one or more of the processor 202, the memory 204, the transmitter 210, and the receiver 212, and may not include the input device 206 and/or the display 208.

The processor 202, in one embodiment, may include any known controller capable of executing computer-readable instructions and/or capable of performing logical operations. For example, the processor 202 may be a microcontroller, a microprocessor, a central processing unit ( “CPU” ) , a graphics processing unit ( “GPU” ) , an auxiliary processing unit, a field programmable gate array ( “FPGA” ) , or similar programmable controller. In some embodiments, the processor 202 executes instructions stored in the memory 204 to perform the methods and routines described herein. The processor 202 is communicatively coupled to the memory 204, the input device 206, the display 208, the transmitter 210, and the receiver 212. In certain embodiments, the processor 202 may select a sequence from a sequence set (each sequence of the sequence set corresponds to a respective sparse code multiple access codeword) , and generate data based on the sparse code multiple access codeword.

The memory 204, in one embodiment, is a computer readable storage medium. In some embodiments, the memory 204 includes volatile computer storage media. For example, the memory 204 may include a RAM, including dynamic RAM ( “DRAM” ) , synchronous dynamic RAM ( “SDRAM” ) , and/or static RAM ( “SRAM” ) . In some embodiments, the memory 204 includes non-volatile computer storage media. For example, the memory 204 may include a hard disk drive, a flash memory, or any other suitable non-volatile computer storage device. In some embodiments, the memory 204 includes both volatile and non-volatile computer storage media. In some embodiments, the memory 204 stores data relating to an indication to be provided to another device. In some embodiments, the memory 204 also stores program code and related data, such as an operating system or other controller algorithms operating on the remote unit 102.

The input device 206, in one embodiment, may include any known computer input device including a touch panel, a button, a keyboard, a stylus, a microphone, or the like. In some embodiments, the input device 206 may be integrated with the display 208, for example, as a touchscreen or similar touch-sensitive display. In some embodiments, the input device 206 includes a touchscreen such that text may be input using a virtual keyboard displayed on the touchscreen and/or by handwriting on the touchscreen. In some embodiments, the input device 206 includes two or more different devices, such as a keyboard and a touch panel.

The display 208, in one embodiment, may include any known electronically controllable display or display device. The display 208 may be designed to output visual, audible, and/or haptic signals. In some embodiments, the display 208 includes an electronic display capable of outputting visual data to a user. For example, the display 208 may include, but is not limited to, an LCD display, an LED display, an OLED display, a projector, or similar display device capable of outputting images, text, or the like to a user. As another, non-limiting, example, the display 208 may include a wearable display such as a smart watch, smart glasses, a heads-up display, or the like. Further, the display 208 may be a component of a smart phone, a personal digital assistant, a television, a table computer, a notebook (laptop) computer, a personal computer, a vehicle dashboard, or the like.

In certain embodiments, the display 208 includes one or more speakers for producing sound. For example, the display 208 may produce an audible alert or notification (e.g., a beep or chime) . In some embodiments, the display 208 includes one or more haptic devices for producing vibrations, motion, or other haptic feedback. In some embodiments, all or portions of the display 208 may be integrated with the input device 206. For example, the input device 206 and display 208 may form a touchscreen or similar touch-sensitive display. In other embodiments, the display 208 may be located near the input device 206.

The transmitter 210 is used to provide UL communication signals to the base unit 104 and the receiver 212 is used to receive DL communication signals from the base unit 104. In one embodiment, the transmitter 210 is used to transmit a sequence on a resource, and transmit data on a resource set determined by a sparse code multiple access codeword. In certain embodiments, the receiver 212 may be used to receive a signal for indicating a resource. The resource may be used for transmitting a sequence that corresponds to a sparse code multiple access codeword. Although only one transmitter 210 and one receiver 212 are illustrated, the remote unit 102 may have any suitable number of transmitters 210 and receivers 212. The transmitter 210 and the receiver 212 may be any suitable type of transmitters and receivers. In one embodiment, the transmitter 210 and the receiver 212 may be part of a transceiver.

Figure 3 depicts one embodiment of an apparatus 300 that may be used for sparse code multiple access communication. The apparatus 300 includes one embodiment of the base unit 104. Furthermore, the base unit 104 may include a processor 302, a memory 304, an input device 306, a display 308, a transmitter 310, and a receiver 312. As may be appreciated, the processor 302, the memory 304, the input device 306, and the display 308 may be substantially similar to the processor 202, the memory 204, the input device 206, and the display 208 of the remote unit 102, respectively.

The transmitter 310 may be used to transmit a first signal to a first device for indicating a first resource. The first resource may be used by the first device to transmit a first sequence, and the first sequence may correspond to a first sparse code multiple access codeword. The receiver 312 may be used to receive the first sequence on the first resource, and receive first data on a first resource set determined based on the first sparse code multiple access codeword. Although only one transmitter 310 and one receiver 312 are illustrated, the base unit 104 may have any suitable number of transmitters 310 and receivers 312. The transmitter 310 and the receiver 312 may be any suitable type of transmitters and receivers. In one embodiment, the transmitter 310 and the receiver 312 may be part of a transceiver.

Figure 4 illustrates one embodiment of communications 400 for sparse code multiple access communication. Specifically, communications 400 between a UE 402 and an eNB 404 are illustrated. A first communication 406 may include information transmitted from the eNB 404 and received by the UE 402. In some embodiments, the information is indicated by RRC signaling. The information may be transmitted using a signal and may include an indication of a resource to be used for transmissions from the UE 402, among other things.

A second communication 408 includes a sequence transmitted from the UE 402 (e.g., remote unit 102) and received by the eNB 404 (e.g., base unit 104) on the resource. In various embodiments, the sequence corresponds to a sparse code multiple access codeword. A third communication 410 may include data transmitted from the UE 402 to the eNB 404 on a resource set determined based on the sparse code multiple access codeword.

Figure 5 illustrates one embodiment of sparse code multiple access resource mapping 500. Specifically, Figure 5 illustrates graphically how six UEs may be mapped to four resources. The six UEs each correspond to a unique codeword and include UE_1 502, UE_2 504, UE_3 506, UE_4 508, UE_5 510, and UE_6 512. Moreover, the four resources include R_1 514, R_2 516, R_3 518, and R_4 520.

The lines connecting the UEs to the resources indicate one embodiment of resources corresponding to the codeword that the UEs may use. For example, the UE_1 502 corresponds to the codeword “1100” which is mapped to the R_1 514 and the R_2 516. Moreover, the UE_2 504 corresponds to the codeword “1010” which is mapped to the R_1 514 and the R_3 518. In addition, the UE_3 506 corresponds to the codeword “1001” which is mapped to the R_1 514 and the R_4 520. Further, the UE_4 508 corresponds to the codeword “0110” which is mapped to the R_2 516 and the R_3 518. The UE_5 510 corresponds to the codeword “0101” which is mapped to the R_2 516 and the R_4 520. Moreover, the UE_6 512 corresponds to the codeword “0011” which is mapped to the R_3 518 and the R_4 520.

The mapping of Figure 5 corresponds to the codewords in the codebook shown in Table 1. In Table 1, each column corresponds to a codeword (e.g., layer) that may be used by a UE and each row corresponds to a resource.

Table 1

1	1	1	0	0	0
1	0	0	1	1	0
0	1	0	1	0	1
0	0	1	0	1	1

In certain embodiments, a message passing algorithm ( “MPA” ) may be used for iterative SCMA detection. During an MPA iteration, messages may be exchanged between user nodes (e.g., UEs) and resource nodes if and only if there is a connection between a user node and a resource node based on the codewords used.

In applications such as mMTC, a remote unit 102 may wake up at random time when the remote unit 102 has data to transmit. At a given time, a base unit 104 may not know which remote units 102 need to transmit； therefore the base unit 104 may be unable to assign codewords used for UL transmission. When SCMA is used in UL contention-based access, a remote unit 102 may choose a codeword randomly from all available codewords for its UL transmission. However, the base unit 104 may not be able to predict which codewords are used for transmission by which remote units 102. Without the knowledge of which codewords are being used, the base unit 104 may have to perform joint codewords detection and SCMA detection. In certain embodiments, a decoder of the base unit 104 may assume that every codeword is being used, while some codewords are transmitted with zero energy. The complexity of the MPA detection may be O (M^a) ， where M is a constant related with the constellation size, and d is the maximum number of codewords sharing a same resources. The complexity may be high if all the codewords in a codebook are decoded at the same time. Therefore, a remote unit 102 may indicate to a base unit 104 which codeword the remote unit 102 is to use. The indication may be made using a resource determined by the base unit 104 and provided to the remote unit 102 using signaling.

In one embodiment, a set of CDMA sequences S＝ {s₁, s₂, …, s_N} may be defined. In such an embodiment, a sequence s_i may correspond to a SCMA codeword c_i in a codebook C＝ {c₁, c₂, …, c_N} . The number of CDMA sequences in the set of CDMA sequences may be the same as the size of the codebook. A set of UL resources (e.g., codeword signaling resource) may be defined (e.g., by a base unit 104) for the sequence transmission. The codeword signaling resources may be separate physical resources from the SCMA data transmission (e.g., see Figures 6 and 7) , or may share the same resources (e.g., see Figure 8) . In embodiments in which the codeword signaling resources and the SCMA data transmission share the same resources, the CDMA sequences may be transmitted in all the data resources used for SCMA transmission, not limited to the resources indicated by a specific SCMA codeword. Among the three codeword signaling resource/SCMA data transmission resource multiplexing schemes illustrated in Figures 6 thorough 8, the time division multiplexing ( “TDM” ) based scheme of Figure 6 facilitates sequence detection to be completed before SCMA decoding, which may result in a least amount of decoding delay. The overlay scheme of Figure 8 facilitates the CDMA sequences to be transmitted with a maximum number of possible resources, which may result in a maximum amount of spreading gain and robust detection performance.

Within the codeword signaling resource, the CDMA sequences indicating the SCMA codewords may be multiplexed in the code domain (e.g., CDMA) . Moreover, a CDMA sequence s_i corresponds to a SCMA codeword c_i. When a remote unit 102 selects a SCMA codeword c_i for its UL contention-based transmission, the remote unit 102 transmits the corresponding CDMA sequence s_i in the codeword signaling resource. At a base unit 104, before the base unit 104 receiver uses the MPA algorithm to decode the SCMA transmission, the base unit 104 may first use a CDMA sequence detector to detect the set of CDMA sequences transmitted in the codeword signaling resource. If the base unit 104 detects the CDMA sequence s_i, the base unit 104 may understand that the codeword s_i is used by a remote unit 102 (or multiple remote units 102) . Therefore, the base unit 104 uses a set of codewords C^D corresponding to the set of CDMA sequences S^D in the MPA decoder for SCMA decoding in the corresponding resources.

Accordingly, by combining CDMA sequence detection with SCMA contention-based UL transmission a base unit 104 may not need to blindly detect an SCMA codeword used and the SCMA detection complexity may be simplified.

Figure 6 is a schematic block diagram illustrating one embodiment of sparse code multiple access uplink transmissions 600. Specifically, a codeword signaling resource ( “CSR” ) 602 and data 604 are transmitted using time division multiplexing such that the CSR 602 and the data 604 are multiplexed in a time domain 606 and use frequency resources 608. The CSR 602 may include a sequence used to indicate a sparse code multiple access codeword.

Figure 7 is a schematic block diagram illustrating another embodiment of sparse code multiple access uplink transmissions 700. Specifically, a CSR 702 and data 704 are transmitted using frequency division multiplexing such that the CSR 702 and the data 704 use time resources 706 and are multiplexed in a frequency domain 708.

Figure 8 is a schematic block diagram illustrating a further embodiment of sparse code multiple access uplink transmissions 800. Specifically, CSR/Data 802 is transmitted using time division multiplexing and frequency division multiplexing such that the CSR/Data 802 overlap in both a time domain 804 and a frequency domain 806.

Figure 9 is a schematic flow chart diagram illustrating one embodiment of a method 900 for sparse code multiple access communication. In some embodiments, the method 900 is performed by an apparatus, such as the base unit 104. In certain embodiments, the method 900 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method 900 may include transmitting 902 a first signal to a first device for indicating a first resource. In such an embodiment, the first resource may be used by the first device to transmit a first sequence, and the first sequence corresponds to a first sparse code multiple access codeword. The method 900 also includes receiving 904 the first sequence on the first resource. The method 900 includes receiving 906 first data on a first resource set determined based on the first sparse code multiple access codeword.

In one embodiment, the method 900 includes transmitting a second signal to a second device for indicating the first resource. In such an embodiment, the first resource is used by the second device for transmitting a second sequence, and the second sequence corresponds to a second sparse code multiple access codeword. In a further embodiment, the method 900 includes receiving the second sequence on the first resource, and receiving second data on a second resource set determined based on the second sparse code multiple access codeword. In some embodiments, the first resource set and the second resource set are different. In certain embodiments, the first resource and the first resource set are multiplexed in a time domain.

Figure 10 is a schematic flow chart diagram illustrating one embodiment of a method 1000 for sparse code multiple access communication. In some embodiments, the method 1000 is performed by an apparatus, such as the remote unit 102. In certain embodiments, the method 1000 may be performed by a processor executing program code, for example, a microcontroller, a microprocessor, a CPU, a GPU, an auxiliary processing unit, a FPGA, or the like.

The method 1000 may include receiving 1002 a signal for indicating a resource. In such an embodiment, the resource may be used for transmitting a sequence that corresponds to a sparse code multiple access codeword. The method 1000 also includes selecting 1004 the sequence from a sequence set. In such an embodiment, each sequence of the sequence set may correspond to a respective sparse code multiple access codeword. The method 1000 includes generating 1006 data based on the sparse code multiple access codeword. The method 1000 also includes transmitting 1008 the sequence on the resource. The method 1000 includes transmitting 1010 the data on a resource set determined by the sparse code multiple access codeword.

Embodiments may be practiced in other specific forms. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope.

Claims

An apparatus comprising:

a transmitter that transmits a first signal to a first device for indicating a first resource, wherein the first resource is used by the first device to transmit a first sequence, and the first sequence corresponds to a first sparse code multiple access codeword； and

a receiver that:

receives the first sequence on the first resource； and

receives first data on a first resource set determined based on the first sparse code multiple access codeword.
The apparatus of claim 1, wherein the transmitter transmits a second signal to a second device for indicating the first resource, wherein the first resource is used by the second device for transmitting a second sequence, and the second sequence corresponds to a second sparse code multiple access codeword.
The apparatus of claim 2, wherein:

the receiver:

receives the second sequence on the first resource； and

receives second data on a second resource set determined based on the second sparse code multiple access codeword.
The apparatus of claim 3, wherein the first resource set and the second resource set are different.
The apparatus of claim 1, wherein the first resource and the first resource set are multiplexed in a time domain.
The apparatus of claim 1, wherein the first resource and the first resource set are multiplexed in a frequency domain.
The apparatus of claim 1, wherein the first resource and the first resource set overlap in both a time domain and a frequency domain.
The apparatus of claim 1, wherein the first sequence is a code division multiple access sequence.
A method comprising:

transmitting a first signal to a first device for indicating a first resource, wherein the first resource is used by the first device to transmit a first sequence, and the first sequence corresponds to a first sparse code multiple access codeword；

receiving the first sequence on the first resource； and

receiving first data on a first resource set determined based on the first sparse code multiple access codeword.
The method of claim 9, further comprising transmitting a second signal to a second device for indicating the first resource, wherein the first resource is used by the second device for transmitting a second sequence, and the second sequence corresponds to a second sparse code multiple access codeword.
The method of claim 10, further comprising:

receiving the second sequence on the first resource； and

receiving second data on a second resource set determined based on the second sparse code multiple access codeword.
The method of claim 11, wherein the first resource set and the second resource set are different.
The method of claim 9, wherein the first resource and the first resource set are multiplexed in a time domain.
The method of claim 9, wherein the first resource and the first resource set are multiplexed in a frequency domain.
The method of claim 9, wherein the first resource and the first resource set overlap in both a time domain and a frequency domain.
The method of claim 9, wherein the first sequence is a code division multiple access sequence.
An apparatus comprising:

a receiver that receives a signal for indicating a resource, wherein the resource is used for transmitting a sequence that corresponds to a sparse code multiple access codeword；

a processor that:

selects the sequence from a sequence set, wherein each sequence of the sequence set corresponds to a respective sparse code multiple access codeword； and

generates data based on the sparse code multiple access codeword； and

a transmitter that:

transmits the sequence on the resource； and

transmits the data on a resource set determined by the sparse code multiple access codeword.
The apparatus of claim 17, wherein the resource and the resource set are multiplexed in a time domain.
The apparatus of claim 17, wherein the resource and the resource set are multiplexed in a frequency domain.
The apparatus of claim 17, wherein the resource and the resource set overlap in both a time domain and a frequency domain.
The apparatus of claim 17, wherein the sequence is a code division multiple access sequence.
A method comprising:

receiving a signal for indicating a resource, wherein the resource is used for transmitting a sequence that corresponds to a sparse code multiple access codeword；

selecting the sequence from a sequence set, wherein each sequence of the sequence set corresponds to a respective sparse code multiple access codeword；

generating data based on the sparse code multiple access codeword；

transmitting the sequence on the resource； and

transmitting the data on a resource set determined by the sparse code multiple access codeword.
The method of claim 22, wherein the resource and the resource set are multiplexed in a time domain.
The method of claim 22, wherein the resource and the resource set are multiplexed in a frequency domain.
The method of claim 22, wherein the resource and the resource set overlap in both a time domain and a frequency domain.
The method of claim 22, wherein the sequence is a code division multiple access sequence.