WO2020227915A1

WO2020227915A1 - Adaptive rate matching for polar codes

Info

Publication number: WO2020227915A1
Application number: PCT/CN2019/086760
Authority: WO
Inventors: Liangming WU; Changlong Xu; Jian Li; Hao Xu; Joseph Binamira Soriaga
Original assignee: Qualcomm Incorporated
Priority date: 2019-05-14
Filing date: 2019-05-14
Publication date: 2020-11-19

Abstract

Methods, systems, and devices for wireless communications are described. A transmitting device may transmit a first transmission of a code block including a first codeword to a receiving device. The first codeword may be encoded using a first polar code and may be rate matched using a first type of rate matching. The transmitting device may receive a negative acknowledgement message corresponding to the first transmission and may determine a second type of rate matching for a second transmission of the code block. The second transmission may include a second codeword, where the second codeword may be encoded using a second polar code and rate matched using a second type of rate matching. The transmitting device may determine the second type of rate matching based on a difference in signal metrics or code rates between the first transmission and the second transmission. The transmitting device may transmit the second transmission.

Description

ADAPTIVE RATE MATCHING FOR POLAR CODES

BACKGROUND

The following relates generally to wireless communications, and more specifically to adaptive rate matching for polar codes.

Wireless communications systems are widely deployed to provide various types of communication content such as voice, video, packet data, messaging, broadcast, and so on. These systems may be capable of supporting communication with multiple users by sharing the available system resources (e.g., time, frequency, and power) . Examples of such multiple-access systems include fourth generation (4G) systems such as Long Term Evolution (LTE) systems, LTE-Advanced (LTE-A) systems, or LTE-A Pro systems, and fifth generation (5G) systems which may be referred to as New Radio (NR) systems. These systems may employ technologies such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , or discrete Fourier transform spread orthogonal frequency division multiplexing (DFT-S-OFDM) . A wireless multiple-access communications system may include a number of base stations or network access nodes, each simultaneously supporting communication for multiple communication devices, which may be otherwise known as user equipment (UE) .

A transmitting device, such as a UE or base station, may encode a set of bits to generate a codeword. In some cases, the transmitting device may use a linear block error correction coding scheme, such as polar coding, to encode the set of bits. After performing the encoding, the transmitting device may transmit the codeword to a receiving device, such as a base station or a UE. Where the encoded set of bits is not decoded successfully at the receiving device, the receiving device may send a negative acknowledgement (NACK) to the transmitting device. The transmitting device may send a re-transmission that includes additional encoded bits (which may be the same or different from the encoded set of bits) to the receiving device, which may in some cases may attempt to decode a combination of the encoded set of bits and the additional encoded bits. Retransmissions may involve challenges in rate matching for linear block error correction coding schemes.

SUMMARY

The described techniques relate to improved methods, systems, devices, and apparatuses that support adaptive rate matching for polar codes. Generally, the described techniques provide for a transmitting device to puncture or shorten a polar-encoded transmission based on signal metrics or code rates between the polar-encoded transmission and a previous polar-encoded transmission. For instance, a transmitting device (e.g., a user equipment (UE) or a base station) may transmit a first transmission of a code block to a receiving device. The first transmission may include a first codeword that may be encoded using a first polar code and may be rate matched using a first type of rate matching (e.g., puncturing or shortening) . The transmitting device may receive a negative acknowledgement (NACK) corresponding to the first transmission and may determine a second type of rate matching for a second transmission of the code block (e.g., a retransmission) . The second transmission may include a second codeword, where the second codeword may be encoded using a second polar code and rate matched using a second type of rate matching. For instance, the second codeword may be rate-matched using block puncturing, block shortening, 2-block puncturing, or 2-block shortening. In some cases, the transmitting device may determine the second type of rate matching based on a difference in signal metrics or code rates between the first transmission and the second transmission. The transmitting device may transmit the second transmission.

A method of wireless communication is described. The method may include transmitting a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching, receiving a negative acknowledgement message corresponding to the first transmission, determining a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission, and transmitting the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching

An apparatus for wireless communication is described. The apparatus may include a processor, memory in electronic communication with the processor, and instructions stored in the memory. The instructions may be executable by the processor to cause the apparatus to transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching, receive a negative acknowledgement message corresponding to the first transmission, determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission, and transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching.

Another apparatus for wireless communication is described. The apparatus may include means for transmitting a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching, receiving a negative acknowledgement message corresponding to the first transmission, determining a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission, and transmitting the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching.

A non-transitory computer-readable medium storing code for wireless communication is described. The code may include instructions executable by a processor to transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching, receive a negative acknowledgement message corresponding to the first transmission, determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission, and transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining the second type of rate matching for the second transmission based on the difference in the signal metrics may include operations, features, means, or instructions for determining whether a difference between a first signal metric for the first transmission and a second signal metric for the second transmission satisfies a threshold, and determining the second type of rate matching for the second transmission based on determining whether the threshold may be satisfied.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for receiving a first indication of the first signal metric for the first transmission and a second indication of the second signal metric for the second transmission, and determining the difference between the first signal metric for the first transmission and the second signal metric for the second transmission based on the received first and second indications.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, receiving each of the first and second indications may include operations, features, means, or instructions for receiving CSI, a SRS, or a combination thereof.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first signal metric for the first transmission and the second signal metric for the second transmission correspond to signal-to-noise ratios for a channel associated with the first and second transmissions.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, determining the second type of rate matching for the second transmission based on the difference in the code rates may include operations, features, means, or instructions for determining whether a difference between a first code rate of the first transmission and a second code rate of the second transmission satisfies a threshold, and determining the second type of rate matching for the second transmission based on determining whether the threshold may be satisfied.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for encoding a first set of information bits according to the first polar code to generate a first set of polar-encoded bits, and encoding a second set of information bits according to the second polar code to generate a second set of polar-encoded bits, where the second set of information bits includes the first set of information bits.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, at least two information bits of the second set of information bits corresponds to one information bit of the first set of information bits.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the second set of polar-encoded bits includes the first set of polar-encoded bits.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining whether a code rate associated with the first transmission satisfies a threshold, and determining the first type of rate matching based on determining whether the threshold may be satisfied.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for transmitting an indication of the second type of rate matching.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the indication may be transmitted via downlink control information scheduling the second transmission.

Some examples of the method, apparatuses, and non-transitory computer-readable medium described herein may further include operations, features, means, or instructions for determining the second type of rate matching for the second transmission may be further based on the first type of rate matching.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first type of rate matching may be puncturing, and where the second type of rate matching may be one of block puncturing, 2 block puncturing, block shortening, or 2 block shortening based on the first type of rate matching being puncturing.

In some examples of the method, apparatuses, and non-transitory computer-readable medium described herein, the first type of rate matching may be shortening, and where the second type of rate matching may be one of block shortening, 2 block shortening, block puncturing, or 2 block puncturing based on the first type of rate matching being shortening.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates an example of a wireless communications system that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 2 illustrates an example of a device that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 3 illustrates an example of an encoding scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 4 illustrates an example of a rate matching decision scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 5 illustrates an example of a block puncturing scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 6 illustrates an example of a block shortening/puncturing scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 7 illustrates an example of a block shortening scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 8 illustrates an example of a block puncturing construction scheme that support adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 9 illustrates an example of a 2-block puncturing scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 10 illustrates an example of a 2-block shortening scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 11 illustrates an example of a puncturing/2-block shortening scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 12 illustrates an example of a 2-block puncturing construction scheme that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 13 illustrates an example of a process flow that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIGs. 14 and 15 show block diagrams of devices that support adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 16 shows a block diagram of a communications manager that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIG. 17 shows a diagram of a system including a device that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

FIGs. 18 through 22 show flowcharts illustrating methods that support adaptive rate matching for polar codes in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

A transmitting device may transmit data (e.g., a code block) to a receiving device. In some cases, the transmitting device may encode the data before performing the transmission. For instance, if the data is represented by a set of bits, the transmitting device may apply a linear block error code to the set of bits. One type of linear block error code that the transmitting device may apply is a polar code. After performing the encoding, the transmitting device may transmit the encoded data to the receiving device.

In some cases, the transmitting device may transmit a first transmission including a first codeword to the receiving device. If the receiving device does not successfully decode the codeword, the receiving device may transmit a negative acknowledgement (NACK) to the transmitting device. Upon receiving the NACK, the transmitting device may transmit a retransmission of the first transmission which builds incrementally on the first transmission (e.g., according to a hybrid automatic response request (HARQ) incremental redundancy (IR) scheme) . For instance, the retransmission may include a second codeword, which may contain different encoded bits generated from the code block.

In some examples, the transmitting device may perform rate matching on the first transmission and/or the retransmission. For instance, the transmitting device may puncture or shorten the first transmission. Puncturing may involve truncating or trimming one or more information bits from one side of a codeword and shortening may involve truncating or trimming one or more information bits from the other side of the codeword. Puncturing may also be known as unknown-bit puncturing and shortening may also be known as known-bit puncturing. Additionally, puncturing and shortening may be extended to retransmissions in various ways. For example, the transmitting device may perform block puncturing, 2-block puncturing, block shortening, or 2-block shortening on the retransmission. Block puncturing and block shortening may be contiguous puncturing or shortening, respectively, for the retransmission based on the first transmission. 2-block puncturing and 2-block shortening, meanwhile, may be non-contiguous puncturing or shortening, respectively, for the retransmission based on the first transmission.

According to various aspects, the receiving device may have an increased likelihood of successfully decoding the retransmission if the transmitting device chooses a type of rate matching based on a difference in signal metrics (e.g., signal to noise ratio (SNR) ) or code rates between the first transmission and the retransmission. The increase in likelihood of successful decoding may be due to improved matching between the decoding scheme performance and the code rate. In one example, if a difference in SNR between the first transmission and the retransmission is above an SNR threshold, the transmitting device may increase a likelihood of successfully decoding the retransmission by performing 2-block puncturing or 2-block shortening. Additionally or alternatively, if the difference in SNR is below the SNR threshold, the transmitting device may increase the likelihood of successfully decoding the retransmission by performing block puncturing or block shortening. In another example, if a difference in code rate between the first transmission and the retransmission is above a code rate threshold, the transmitting device may increase a likelihood of successfully decoding the retransmission by performing block puncturing or block shortening. Additionally or alternatively, if the difference in code rate between the first transmission and the retransmission is below the code rate threshold, the transmitting device may increase the likelihood of successfully decoding the retransmission by performing 2-block puncturing or 2-block shortening. In some cases, the type of rate matching for the retransmission may be determined based on the type of rate matching for the first transmission. For instance, if the type of rate matching for the first transmission is puncturing, the type of rate matching for the retransmission may be block puncturing or 2-block puncturing and, if the type of rate matching for the first transmission is shortening, the type of rate matching for the retransmission may be block shortening or 2-block shortening.

Aspects of the disclosure are initially described in the context of a wireless communications system. Additional aspects of the disclosure may be described in the context of a device, an encoding scheme, a rate matching decision scheme, a block puncturing scheme, a block puncturing/shortening scheme, a block shortening scheme, a block puncturing construction scheme, a 2-block puncturing scheme, a 2-block shortening scheme, a puncturing/2-block shortening scheme, a 2-block puncturing construction scheme, and a process flow. Aspects of the disclosure are further illustrated by and described with reference to apparatus diagrams, system diagrams, and flowcharts that relate to adaptive rate matching for polar codes.

FIG. 1 illustrates an example of a wireless communications system 100 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The wireless communications system 100 includes base stations 105, UEs 115, and a core network 130. In some examples, the wireless communications system 100 may be a Long Term Evolution (LTE) network, an LTE-Advanced (LTE-A) network, an LTE-A Pro network, or a New Radio (NR) network. In some cases, wireless communications system 100 may support enhanced broadband communications, ultra-reliable (e.g., mission critical) communications, low latency communications, or communications with low-cost and low-complexity devices.

Base stations 105 may wirelessly communicate with UEs 115 via one or more base station antennas. Base stations 105 described herein may include or may be referred to by those skilled in the art as a base transceiver station, a radio base station, an access point, a radio transceiver, a NodeB, an eNodeB (eNB) , a next-generation NodeB or giga-NodeB (either of which may be referred to as a gNB) , a Home NodeB, a Home eNodeB, or some other suitable terminology. Wireless communications system 100 may include base stations 105 of different types (e.g., macro or small cell base stations) . The UEs 115 described herein may be able to communicate with various types of base stations 105 and network equipment including macro eNBs, small cell eNBs, gNBs, relay base stations, and the like.

Each base station 105 may be associated with a particular geographic coverage area 110 in which communications with various UEs 115 is supported. Each base station 105 may provide communication coverage for a respective geographic coverage area 110 via communication links 125, and communication links 125 between a base station 105 and a UE 115 may utilize one or more carriers. Communication links 125 shown in wireless communications system 100 may include uplink transmissions from a UE 115 to a base station 105, or downlink transmissions from a base station 105 to a UE 115. Downlink transmissions may also be called forward link transmissions while uplink transmissions may also be called reverse link transmissions.

The geographic coverage area 110 for a base station 105 may be divided into sectors making up a portion of the geographic coverage area 110, and each sector may be associated with a cell. For example, each base station 105 may provide communication coverage for a macro cell, a small cell, a hot spot, or other types of cells, or various combinations thereof. In some examples, a base station 105 may be movable and therefore provide communication coverage for a moving geographic coverage area 110. In some examples, different geographic coverage areas 110 associated with different technologies may overlap, and overlapping geographic coverage areas 110 associated with different technologies may be supported by the same base station 105 or by different base stations 105. The wireless communications system 100 may include, for example, a heterogeneous LTE/LTE-A/LTE-A Pro or NR network in which different types of base stations 105 provide coverage for various geographic coverage areas 110.

The term “cell” refers to a logical communication entity used for communication with a base station 105 (e.g., over a carrier) , and may be associated with an identifier for distinguishing neighboring cells (e.g., a physical cell identifier (PCID) , a virtual cell identifier (VCID) ) operating via the same or a different carrier. In some examples, a carrier may support multiple cells, and different cells may be configured according to different protocol types (e.g., machine-type communication (MTC) , narrowband Internet-of-Things (NB-IoT) , enhanced mobile broadband (eMBB) , or others) that may provide access for different types of devices. In some cases, the term “cell” may refer to a portion of a geographic coverage area 110 (e.g., a sector) over which the logical entity operates.

UEs 115 may be dispersed throughout the wireless communications system 100, and each UE 115 may be stationary or mobile. A UE 115 may also be referred to as a mobile device, a wireless device, a remote device, a handheld device, or a subscriber device, or some other suitable terminology, where the “device” may also be referred to as a unit, a station, a terminal, or a client. A UE 115 may also be a personal electronic device such as a cellular phone, a personal digital assistant (PDA) , a tablet computer, a laptop computer, or a personal computer. In some examples, a UE 115 may also refer to a wireless local loop (WLL) station, an Internet of Things (IoT) device, an Internet of Everything (IoE) device, or an MTC device, or the like, which may be implemented in various articles such as appliances, vehicles, meters, or the like.

Some UEs 115, such as MTC or IoT devices, may be low cost or low complexity devices, and may provide for automated communication between machines (e.g., via Machine-to-Machine (M2M) communication) . M2M communication or MTC may refer to data communication technologies that allow devices to communicate with one another or a base station 105 without human intervention. In some examples, M2M communication or MTC may include communications from devices that integrate sensors or meters to measure or capture information and relay that information to a central server or application program that can make use of the information or present the information to humans interacting with the program or application. Some UEs 115 may be designed to collect information or enable automated behavior of machines. Examples of applications for MTC devices include smart metering, inventory monitoring, water level monitoring, equipment monitoring, healthcare monitoring, wildlife monitoring, weather and geological event monitoring, fleet management and tracking, remote security sensing, physical access control, and transaction-based business charging.

Some UEs 115 may be configured to employ operating modes that reduce power consumption, such as half-duplex communications (e.g., a mode that supports one-way communication via transmission or reception, but not transmission and reception simultaneously) . In some examples half-duplex communications may be performed at a reduced peak rate. Other power conservation techniques for UEs 115 include entering a power saving “deep sleep” mode when not engaging in active communications, or operating over a limited bandwidth (e.g., according to narrowband communications) . In some cases, UEs 115 may be designed to support critical functions (e.g., mission critical functions) , and a wireless communications system 100 may be configured to provide ultra-reliable communications for these functions.

In some cases, a UE 115 may also be able to communicate directly with other UEs 115 (e.g., using a peer-to-peer (P2P) or device-to-device (D2D) protocol) . One or more of a group of UEs 115 utilizing D2D communications may be within the geographic coverage area 110 of a base station 105. Other UEs 115 in such a group may be outside the geographic coverage area 110 of a base station 105, or be otherwise unable to receive transmissions from a base station 105. In some cases, groups of UEs 115 communicating via D2D communications may utilize a one-to-many (1: M) system in which each UE 115 transmits to every other UE 115 in the group. In some cases, a base station 105 facilitates the scheduling of resources for D2D communications. In other cases, D2D communications are carried out between UEs 115 without the involvement of a base station 105.

Base stations 105 may communicate with the core network 130 and with one another. For example, base stations 105 may interface with the core network 130 through backhaul links 132 (e.g., via an S1, N2, N3, or other interface) . Base stations 105 may communicate with one another over backhaul links 134 (e.g., via an X2, Xn, or other interface) either directly (e.g., directly between base stations 105) or indirectly (e.g., via core network 130) .

The core network 130 may provide user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. The core network 130 may be an evolved packet core (EPC) , which may include at least one mobility management entity (MME) , at least one serving gateway (S-GW) , and at least one Packet Data Network (PDN) gateway (P-GW) . The MME may manage non-access stratum (e.g., control plane) functions such as mobility, authentication, and bearer management for UEs 115 served by base stations 105 associated with the EPC. User IP packets may be transferred through the S-GW, which itself may be connected to the P-GW. The P-GW may provide IP address allocation as well as other functions. The P-GW may be connected to the network operators IP services. The operators IP services may include access to the Internet, Intranet (s) , an IP Multimedia Subsystem (IMS) , or a Packet-Switched (PS) Streaming Service.

At least some of the network devices, such as a base station 105, may include subcomponents such as an access network entity, which may be an example of an access node controller (ANC) . Each access network entity may communicate with UEs 115 through a number of other access network transmission entities, which may be referred to as a radio head, a smart radio head, or a transmission/reception point (TRP) . In some configurations, various functions of each access network entity or base station 105 may be distributed across various network devices (e.g., radio heads and access network controllers) or consolidated into a single network device (e.g., a base station 105) .

Wireless communications system 100 may operate using one or more frequency bands, typically in the range of 300 megahertz (MHz) to 300 gigahertz (GHz) . Generally, the region from 300 MHz to 3 GHz is known as the ultra-high frequency (UHF) region or decimeter band, since the wavelengths range from approximately one decimeter to one meter in length. UHF waves may be blocked or redirected by buildings and environmental features. However, the waves may penetrate structures sufficiently for a macro cell to provide service to UEs 115 located indoors. Transmission of UHF waves may be associated with smaller antennas and shorter range (e.g., less than 100 km) compared to transmission using the smaller frequencies and longer waves of the high frequency (HF) or very high frequency (VHF) portion of the spectrum below 300 MHz.

Wireless communications system 100 may also operate in a super high frequency (SHF) region using frequency bands from 3 GHz to 30 GHz, also known as the centimeter band. The SHF region includes bands such as the 5 GHz industrial, scientific, and medical (ISM) bands, which may be used opportunistically by devices that may be capable of tolerating interference from other users.

Wireless communications system 100 may also operate in an extremely high frequency (EHF) region of the spectrum (e.g., from 30 GHz to 300 GHz) , also known as the millimeter band. In some examples, wireless communications system 100 may support millimeter wave (mmW) communications between UEs 115 and base stations 105, and EHF antennas of the respective devices may be even smaller and more closely spaced than UHF antennas. In some cases, this may facilitate use of antenna arrays within a UE 115. However, the propagation of EHF transmissions may be subject to even greater atmospheric attenuation and shorter range than SHF or UHF transmissions. Techniques disclosed herein may be employed across transmissions that use one or more different frequency regions, and designated use of bands across these frequency regions may differ by country or regulating body.

In some cases, wireless communications system 100 may utilize both licensed and unlicensed radio frequency spectrum bands. For example, wireless communications system 100 may employ License Assisted Access (LAA) , LTE-Unlicensed (LTE-U) radio access technology, or NR technology in an unlicensed band such as the 5 GHz ISM band. When operating in unlicensed radio frequency spectrum bands, wireless devices such as base stations 105 and UEs 115 may employ listen-before-talk (LBT) procedures to ensure a frequency channel is clear before transmitting data. In some cases, operations in unlicensed bands may be based on a carrier aggregation configuration in conjunction with component carriers operating in a licensed band (e.g., LAA) . Operations in unlicensed spectrum may include downlink transmissions, uplink transmissions, peer-to-peer transmissions, or a combination of these. Duplexing in unlicensed spectrum may be based on frequency division duplexing (FDD) , time division duplexing (TDD) , or a combination of both.

In some examples, base station 105 or UE 115 may be equipped with multiple antennas, which may be used to employ techniques such as transmit diversity, receive diversity, multiple-input multiple-output (MIMO) communications, or beamforming. For example, wireless communications system 100 may use a transmission scheme between a transmitting device (e.g., a base station 105) and a receiving device (e.g., a UE 115) , where the transmitting device is equipped with multiple antennas and the receiving device is equipped with one or more antennas. MIMO communications may employ multipath signal propagation to increase the spectral efficiency by transmitting or receiving multiple signals via different spatial layers, which may be referred to as spatial multiplexing. The multiple signals may, for example, be transmitted by the transmitting device via different antennas or different combinations of antennas. Likewise, the multiple signals may be received by the receiving device via different antennas or different combinations of antennas. Each of the multiple signals may be referred to as a separate spatial stream, and may carry bits associated with the same data stream (e.g., the same codeword) or different data streams. Different spatial layers may be associated with different antenna ports used for channel measurement and reporting. MIMO techniques include single-user MIMO (SU-MIMO) where multiple spatial layers are transmitted to the same receiving device, and multiple-user MIMO (MU-MIMO) where multiple spatial layers are transmitted to multiple devices.

Beamforming, which may also be referred to as spatial filtering, directional transmission, or directional reception, is a signal processing technique that may be used at a transmitting device or a receiving device (e.g., a base station 105 or a UE 115) to shape or steer an antenna beam (e.g., a transmit beam or receive beam) along a spatial path between the transmitting device and the receiving device. Beamforming may be achieved by combining the signals communicated via antenna elements of an antenna array such that signals propagating at particular orientations with respect to an antenna array experience constructive interference while others experience destructive interference. The adjustment of signals communicated via the antenna elements may include a transmitting device or a receiving device applying certain amplitude and phase offsets to signals carried via each of the antenna elements associated with the device. The adjustments associated with each of the antenna elements may be defined by a beamforming weight set associated with a particular orientation (e.g., with respect to the antenna array of the transmitting device or receiving device, or with respect to some other orientation) .

In one example, a base station 105 may use multiple antennas or antenna arrays to conduct beamforming operations for directional communications with a UE 115. For instance, some signals (e.g. synchronization signals, reference signals, beam selection signals, or other control signals) may be transmitted by a base station 105 multiple times in different directions, which may include a signal being transmitted according to different beamforming weight sets associated with different directions of transmission. Transmissions in different beam directions may be used to identify (e.g., by the base station 105 or a receiving device, such as a UE 115) a beam direction for subsequent transmission and/or reception by the base station 105.

Some signals, such as data signals associated with a particular receiving device, may be transmitted by a base station 105 in a single beam direction (e.g., a direction associated with the receiving device, such as a UE 115) . In some examples, the beam direction associated with transmissions along a single beam direction may be determined based at least in in part on a signal that was transmitted in different beam directions. For example, a UE 115 may receive one or more of the signals transmitted by the base station 105 in different directions, and the UE 115 may report to the base station 105 an indication of the signal it received with a highest signal quality, or an otherwise acceptable signal quality. Although these techniques are described with reference to signals transmitted in one or more directions by a base station 105, a UE 115 may employ similar techniques for transmitting signals multiple times in different directions (e.g., for identifying a beam direction for subsequent transmission or reception by the UE 115) , or transmitting a signal in a single direction (e.g., for transmitting data to a receiving device) .

A receiving device (e.g., a UE 115, which may be an example of a mmW receiving device) may try multiple receive beams when receiving various signals from the base station 105, such as synchronization signals, reference signals, beam selection signals, or other control signals. For example, a receiving device may try multiple receive directions by receiving via different antenna subarrays, by processing received signals according to different antenna subarrays, by receiving according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, or by processing received signals according to different receive beamforming weight sets applied to signals received at a plurality of antenna elements of an antenna array, any of which may be referred to as “listening” according to different receive beams or receive directions. In some examples a receiving device may use a single receive beam to receive along a single beam direction (e.g., when receiving a data signal) . The single receive beam may be aligned in a beam direction determined based at least in part on listening according to different receive beam directions (e.g., a beam direction determined to have a highest signal strength, highest signal-to-noise ratio, or otherwise acceptable signal quality based at least in part on listening according to multiple beam directions) .

In some cases, the antennas of a base station 105 or UE 115 may be located within one or more antenna arrays, which may support MIMO operations, or transmit or receive beamforming. For example, one or more base station antennas or antenna arrays may be co-located at an antenna assembly, such as an antenna tower. In some cases, antennas or antenna arrays associated with a base station 105 may be located in diverse geographic locations. A base station 105 may have an antenna array with a number of rows and columns of antenna ports that the base station 105 may use to support beamforming of communications with a UE 115. Likewise, a UE 115 may have one or more antenna arrays that may support various MIMO or beamforming operations.

In some cases, wireless communications system 100 may be a packet-based network that operate according to a layered protocol stack. In the user plane, communications at the bearer or Packet Data Convergence Protocol (PDCP) layer may be IP-based. A Radio Link Control (RLC) layer may perform packet segmentation and reassembly to communicate over logical channels. A Medium Access Control (MAC) layer may perform priority handling and multiplexing of logical channels into transport channels. The MAC layer may also use hybrid automatic repeat request (HARQ) to provide retransmission at the MAC layer to improve link efficiency. In the control plane, the Radio Resource Control (RRC) protocol layer may provide establishment, configuration, and maintenance of an RRC connection between a UE 115 and a base station 105 or core network 130 supporting radio bearers for user plane data. At the Physical layer, transport channels may be mapped to physical channels.

In some cases, UEs 115 and base stations 105 may support retransmissions of data to increase the likelihood that data is received successfully. HARQ feedback is one technique of increasing the likelihood that data is received correctly over a communication link 125. HARQ may include a combination of error detection (e.g., using a cyclic redundancy check (CRC) ) , forward error correction (FEC) , and retransmission (e.g., automatic repeat request (ARQ) ) . HARQ may improve throughput at the MAC layer in poor radio conditions (e.g., signal-to-noise conditions) . In some cases, a wireless device may support same-slot HARQ feedback, where the device may provide HARQ feedback in a specific slot for data received in a previous symbol in the slot. In other cases, the device may provide HARQ feedback in a subsequent slot, or according to some other time interval.

Time intervals in LTE or NR may be expressed in multiples of a basic time unit, which may, for example, refer to a sampling period of T _s = 1/30,720,000 seconds. Time intervals of a communications resource may be organized according to radio frames each having a duration of 10 milliseconds (ms) , where the frame period may be expressed as T _f = 307,200 T _s. The radio frames may be identified by a system frame number (SFN) ranging from 0 to 1023. Each frame may include 10 subframes numbered from 0 to 9, and each subframe may have a duration of 1 ms. A subframe may be further divided into 2 slots each having a duration of 0.5 ms, and each slot may contain 6 or 7 modulation symbol periods (e.g., depending on the length of the cyclic prefix prepended to each symbol period) . Excluding the cyclic prefix, each symbol period may contain 2048 sampling periods. In some cases, a subframe may be the smallest scheduling unit of the wireless communications system 100, and may be referred to as a transmission time interval (TTI) . In other cases, a smallest scheduling unit of the wireless communications system 100 may be shorter than a subframe or may be dynamically selected (e.g., in bursts of shortened TTIs (sTTIs) or in selected component carriers using sTTIs) .

In some wireless communications systems, a slot may further be divided into multiple mini-slots containing one or more symbols. In some instances, a symbol of a mini-slot or a mini-slot may be the smallest unit of scheduling. Each symbol may vary in duration depending on the subcarrier spacing or frequency band of operation, for example. Further, some wireless communications systems may implement slot aggregation in which multiple slots or mini-slots are aggregated together and used for communication between a UE 115 and a base station 105.

The term “carrier” refers to a set of radio frequency spectrum resources having a defined physical layer structure for supporting communications over a communication link 125. For example, a carrier of a communication link 125 may include a portion of a radio frequency spectrum band that is operated according to physical layer channels for a given radio access technology. Each physical layer channel may carry user data, control information, or other signaling. A carrier may be associated with a pre-defined frequency channel (e.g., an evolved universal mobile telecommunication system terrestrial radio access (E-UTRA) absolute radio frequency channel number (EARFCN) ) , and may be positioned according to a channel raster for discovery by UEs 115. Carriers may be downlink or uplink (e.g., in an FDD mode) , or be configured to carry downlink and uplink communications (e.g., in a TDD mode) . In some examples, signal waveforms transmitted over a carrier may be made up of multiple sub-carriers (e.g., using multi-carrier modulation (MCM) techniques such as orthogonal frequency division multiplexing (OFDM) or discrete Fourier transform spread OFDM (DFT-S-OFDM) ) .

The organizational structure of the carriers may be different for different radio access technologies (e.g., LTE, LTE-A, LTE-A Pro, NR) . For example, communications over a carrier may be organized according to TTIs or slots, each of which may include user data as well as control information or signaling to support decoding the user data. A carrier may also include dedicated acquisition signaling (e.g., synchronization signals or system information, etc. ) and control signaling that coordinates operation for the carrier. In some examples (e.g., in a carrier aggregation configuration) , a carrier may also have acquisition signaling or control signaling that coordinates operations for other carriers.

Physical channels may be multiplexed on a carrier according to various techniques. A physical control channel and a physical data channel may be multiplexed on a downlink carrier, for example, using time division multiplexing (TDM) techniques, frequency division multiplexing (FDM) techniques, or hybrid TDM-FDM techniques. In some examples, control information transmitted in a physical control channel may be distributed between different control regions in a cascaded manner (e.g., between a common control region or common search space and one or more UE-specific control regions or UE-specific search spaces) .

A carrier may be associated with a particular bandwidth of the radio frequency spectrum, and in some examples the carrier bandwidth may be referred to as a “system bandwidth” of the carrier or the wireless communications system 100. For example, the carrier bandwidth may be one of a number of predetermined bandwidths for carriers of a particular radio access technology (e.g., 1.4, 3, 5, 10, 15, 20, 40, or 80 MHz) . In some examples, each served UE 115 may be configured for operating over portions or all of the carrier bandwidth. In other examples, some UEs 115 may be configured for operation using a narrowband protocol type that is associated with a predefined portion or range (e.g., set of subcarriers or RBs) within a carrier (e.g., “in-band” deployment of a narrowband protocol type) .

In a system employing MCM techniques, a resource element may consist of one symbol period (e.g., a duration of one modulation symbol) and one subcarrier, where the symbol period and subcarrier spacing are inversely related. The number of bits carried by each resource element may depend on the modulation scheme (e.g., the order of the modulation scheme) . Thus, the more resource elements that a UE 115 receives and the higher the order of the modulation scheme, the higher the data rate may be for the UE 115. In MIMO systems, a wireless communications resource may refer to a combination of a radio frequency spectrum resource, a time resource, and a spatial resource (e.g., spatial layers) , and the use of multiple spatial layers may further increase the data rate for communications with a UE 115.

Devices of the wireless communications system 100 (e.g., base stations 105 or UEs 115) may have a hardware configuration that supports communications over a particular carrier bandwidth, or may be configurable to support communications over one of a set of carrier bandwidths. In some examples, the wireless communications system 100 may include base stations 105 and/or UEs 115 that support simultaneous communications via carriers associated with more than one different carrier bandwidth.

Wireless communications system 100 may support communication with a UE 115 on multiple cells or carriers, a feature which may be referred to as carrier aggregation or multi-carrier operation. A UE 115 may be configured with multiple downlink component carriers and one or more uplink component carriers according to a carrier aggregation configuration. Carrier aggregation may be used with both FDD and TDD component carriers.

In some cases, wireless communications system 100 may utilize enhanced component carriers (eCCs) . An eCC may be characterized by one or more features including wider carrier or frequency channel bandwidth, shorter symbol duration, shorter TTI duration, or modified control channel configuration. In some cases, an eCC may be associated with a carrier aggregation configuration or a dual connectivity configuration (e.g., when multiple serving cells have a suboptimal or non-ideal backhaul link) . An eCC may also be configured for use in unlicensed spectrum or shared spectrum (e.g., where more than one operator is allowed to use the spectrum) . An eCC characterized by wide carrier bandwidth may include one or more segments that may be utilized by UEs 115 that are not capable of monitoring the whole carrier bandwidth or are otherwise configured to use a limited carrier bandwidth (e.g., to conserve power) .

In some cases, an eCC may utilize a different symbol duration than other component carriers, which may include use of a reduced symbol duration as compared with symbol durations of the other component carriers. A shorter symbol duration may be associated with increased spacing between adjacent subcarriers. A device, such as a UE 115 or base station 105, utilizing eCCs may transmit wideband signals (e.g., according to frequency channel or carrier bandwidths of 20, 40, 60, 80 MHz, etc. ) at reduced symbol durations (e.g., 16.67 microseconds) . A TTI in eCC may consist of one or multiple symbol periods. In some cases, the TTI duration (that is, the number of symbol periods in a TTI) may be variable.

Wireless communications system 100 may be an NR system that may utilize any combination of licensed, shared, and unlicensed spectrum bands, among others. The flexibility of eCC symbol duration and subcarrier spacing may allow for the use of eCC across multiple spectrums. In some examples, NR shared spectrum may increase spectrum utilization and spectral efficiency, specifically through dynamic vertical (e.g., across the frequency domain) and horizontal (e.g., across the time domain) sharing of resources.

In cases where a transmitting device (e.g., a UE 115 or a base station 105) transmits data according to HARQ-IR, the transmitting device may obtain more coding gain with increased polarization. In general, operating according to HARQ-IR may involve using multiple transmissions (e.g., transmissions and retransmissions) to build a composite transmission, which may provide increased coding gain over retransmission of the same coded bits (e.g., chase combining) . In some cases, a transmitting device operating according to HARQ-IR may employ rate matching. The rate matching scheme may be feasible for construction (e.g., avoids the device having to perform in-line gaussian approximation (GA) or density evolution (DE) computations) and may have robustness to channel fading. Both shortening and puncturing may be applied in HARQ-IR. Block puncturing and shortening may be information adjustment allocation (IAA) based constructions and 2-block puncturing and shortening may be GA approximated constructions. According to various aspects, communications performance may improve when a transmitting device employs HARQ-IR rate matching adaptation.

In some cases, a transmitting device (e.g., a UE 115 or a base station 105) may transmit a first transmission of a code block to a receiving device. The first transmission may include a first codeword that may be encoded using a first polar code and may be rate matched using a first type of rate matching (e.g., puncturing or shortening) . The transmitting device may receive a NACK corresponding to the first transmission and may determine a second type of rate matching for a second transmission of the code block (e.g., a retransmission) . The second transmission may include a second codeword, where the second codeword may be encoded using a second polar code and rate matched using a second type of rate matching. For instance, the second codeword may be rate-matched using block puncturing, block shortening, 2-block puncturing, or 2-block shortening. In some cases, the transmitting device may determine the second type of rate matching based on a difference in signal metrics or code rates between the first transmission and the second transmission. The transmitting device may transmit the second transmission.

In general, the methods described herein may provide one or more potential advantages. For instance, determining the second type rate matching based on a difference in signal metrics or code rates between the first and second transmissions may improve the likelihood of successful decoding for the first and/or second transmissions. As such, on average, the latency associated with transmitting the code block may decrease (e.g., the increased likelihood of successful decoding using the first and/or second transmissions may reduce the likelihood of a third transmission for the code block, which may be associated with an increased latency) .

FIG. 2 illustrates an example of a device 200 that supports adaptive rate matching for polar codes in accordance with various aspects of the present disclosure. In some examples, device 200 may implement aspects of wireless communications system 100. The device 200 may be any device within a wireless communications system 100 that performs an encoding or decoding process (e.g., using an error-correcting code, such as a polar code) . Device 200 may be an example of a UE 115 or a base station 105 as described with reference to FIG. 1.

As shown, device 200 includes a memory 205, an encoder/decoder 210, and a transmitter/receiver 215. First bus 220 may connect memory 205 to encoder/decoder 210 and second bus 225 may connect encoder/decoder 210 to transmitter/receiver 215. In some cases, device 200 may have data stored in memory 205 to be transmitted to another device, such as a UE 115 or base station 105. To initiate the transmission process, device 200 may retrieve from memory 205 the data for transmission. The data may include a number of payload bits, ‘A,’ which may be 1s or 0s, provided from memory 205 to encoder/decoder 210 via first bus 220. In some cases, these payload bits may be combined with a number of parity or error checking bits, ‘E, ’ to form a total set of information bits, ‘A+E. ’ The number of information bits may be represented as a value ‘D, ’as shown. The encoder/decoder 210 may implement a polar code with a block length, ‘N, ’ for encoding the information bits, where N may be different than or the same as D. Such a polar code may be referred to as an (N, D) polar code. In some cases, the bits that not allocated as information bits (i.e., N -D bits) may be assigned as frozen bits.

In some cases, to perform a polar coding operation, the encoder 210 may generate a codeword of length, ‘M, ’ where M is a power of 2 (i.e., M=2 ^m where m is an integer value) . If the codeword length M is not a power of 2, the encoder 210 may round the value of M up to the nearest valid M value. For example, if M = 400, the encoder 210 may determine a codeword length of N = 512 (e.g., the nearest valid value for N greater than or equal to M) in order to support polar coding. In these cases, the encoder 210 may encode a codeword of length N, and then may puncture (e.g., using block puncturing or, shortening) a number of bitsN-M to obtain a codeword of the specified block length Mfor transmission.

The encoder 210 may attempt to assign the information bits to the D most reliable bit channels, and the frozen bits to the remaining bit channels. The encoder/decoder 210 may use a variety of techniques to select the most reliable bit channels. For example, polarization weight (PW) , generator weight (GW) , GA, or DE are common techniques used for estimating bit channel reliability for polar codes. In some cases (e.g., for large values of M or N, such as M = 1024) , the encoder/decoder 210 may implement IAA-based techniques such as fractally enhanced kernel (FRANK) polar code construction for assigning the K information bits to the most (or an estimation of the most) reliable bit channels. IAA polar code construction may provide better estimates of bit channel reliability than some polar coding schemes (e.g., PW, GW, etc. ) , and may be less complex than other polar coding schemes (e.g., GA, DE) . Additionally, IAA polar code construction may allow the encoder 210 to flexibly adapt the code rate when generating codewords via puncturing. The encoder 210 may determine information bit channels based on IAA polar code construction and may assign frozen bits to the remaining channels. Frozen bits may be bits of a default value (e.g., 0, 1, etc. ) known to both the encoder and decoder (i.e., the encoder encoding information bits at a transmitter and the decoder decoding the codeword received at a receiver) . Further, from the receiving device perspective, device 200 may receive a data signal representing the codeword via receiver 215 and may decode the signal using decoder 210 to obtain the transmitted data.

In some wireless systems, decoder 210 may be an example of a successive cancellation (SC) or a successive cancellation list (SCL) decoder. A UE 115 or base station 105 may receive a transmission including a set of encoded bits of a codeword (e.g., symbol information representing the unpunctured bits of the codeword) at receiver 215 and may send the transmission to the SCL decoder (e.g., decoder 210) . The SCL decoder may determine input logarithmic-likelihood ratios (LLRs) for the bit channels of the received codeword. During decoding, the SCL decoder may determine decoded LLRs based on these input LLRs, where the decoded LLRs correspond to each bit channel of the polar code. These decoded LLRs may be referred to as bit metrics. In some cases, if the LLR is zero or a positive value, the SCL decoder may determine the corresponding bit is a 0 bit, and a negative LLR may correspond to a 1 bit. The SCL decoder may use the bit metrics to determine the decoded bit values.

The SCL decoder may employ multiple concurrent SC decoding processes. Each SC decoding process may decode the codeword sequentially (e.g., in order of the bit channel indices) . Due to the combination of multiple SC decoding processes, the SCL decoder may calculate multiple decoding path candidates. For example, an SCL decoder of list size ‘L’ (i.e., the SCL decoder has L SC decoding processes) may calculate L decoding path candidates, and a corresponding reliability metric (e.g., a path metric) for each decoding path candidate. The path metric may represent a reliability of a decoding path candidate or a probability that the corresponding decoding path candidate is the correct set of decoded bits. The path metric may be based on the determined bit metrics and the bit values selected at each bit channel. For example, the SCL decoder may extend each of the L decoding path candidates with both 0 and 1 bit values at information bit locations and determine path metrics for each of the resulting 2L decoding path candidates. The SCL decoder may update path metrics at frozen bit locations for each of the L decoding path candidates. The SCL decoder may have a number of levels equal to the number of bit channels in the received codeword. At each level, each decoding path candidate may select either a 0 bit or a 1 bit based on a path metric of the 0 bit and the 1 bit. The SCL decoder may select a decoding path candidate based on the path metrics and may output the bits corresponding to the selected decoding path as the decoded sets of bits. For example, the SCL decoder may select the decoding paths with the highest path metrics.

The transmitting devices and receiving devices may also use HARQ operations to increase the reliability of a communications link. HARQ operation may include retransmitting information related to previously transmitted codewords one or more times, allowing a receiving device to perform successive decoding operations. Each decoding operation may provide the receiving device with additional information for decoding and increase the likelihood of a successful decoding of the codeword. In some cases, retransmissions benefit from improved channel conditions or enhanced transmit parameters relative to the first transmission, further increasing the likelihood of a successful decoding of the codeword.

In some examples, transmitting devices and receiving devices may use polar coding in combination with HARQ operation to further increase the reliability of a communications link. As discussed above, polar codes may approach the theoretical channel capacity as the code length increases, and each retransmission for a HARQ operation may effectively increase the code length of a data transmission as well as providing more codeword information (increasing coding gain) . In some cases, a first codeword of a first transmission may be associated with a polar code of a first size N, a second codeword of a first retransmission may be associated with a polar code of a second size 2N, a third codeword of a second retransmission may be associated with a polar code of the second size or a third size (e.g., 4N) , and so on. Thus, the likelihood of decoding each successive codeword (e.g., combined with earlier codewords) may increase. In general, a transmitting device may transmit a retransmission with the effectively increased code length if the receiving device is not able to correctly decode the first transmission. For instance, the receiving device may send a negative acknowledgement (NACK) to the transmitting device, which may trigger the transmitting device to transmit the retransmission.

In some cases, the transmitting device may transmit the first transmission with a first type of rate matching, such as puncturing or shortening. When transmitting the first transmission with puncturing, the transmitting device may puncture one or more bits from the start of a codeword (e.g., bit channels associated with a start of a decoding order of the codeword) to be transmitted and when transmitting the first transmission with shortening, the transmitting device may puncture one or more bits from the end of the codeword (e.g., bit channels associated with the end of a decoding order of the codeword) to be transmitted. The bit channels at the start of the decoding order may be understood as unknown bits, and thus puncturing may be called unknown-bit puncturing. Conversely, the bit channels at the end of the decoding order may be understood as known bits (e.g., having a value that is determined only from bit channels being punctured) , and thus shortening may be called known-bit puncturing. In such cases, the transmitting device may process the bit channels corresponding to the punctured or shortened bits as if the bit channels have a capacity and mutual information of 0 (e.g., treat the corresponding input bit-channel as a frozen bit) . More details may be described with reference to FIG. 3.

In some cases, the transmitting device may determine the first type of rate matching based on a code rate associated with the first transmission. For instance, if the code rate is above a threshold, the transmitting device may perform puncturing for the first transmission and, if the code rate is below the threshold, the transmitting device may perform shortening for the first transmission.

The transmitting device may transmit the retransmission with a second type of rate matching, such as block puncturing (e.g., described with reference to FIGs. 5 and 6) , block shortening (e.g., described with reference to FIG. 7) , 2-block puncturing (e.g., described with reference to FIG. 9) , and 2-block shortening (e.g., described with reference to FIGs. 10 and 11) . The transmitting device may determine the second type of rate matching based on the first type of rate matching. In one example, if the first type of rate matching is puncturing, the second type may be constrained to be one or more of block puncturing, 2-block puncturing, or 2-block shortening based on the first type of rate matching being puncturing. In another example, if the first type of rate matching is shortening, the second type of rate matching may be constrained to be one or more of block puncturing, block shortening, or 2-block shortening based on the first type of rate matching being shortening. In some examples, the type of rate matching for additional transmissions may be constrained to be a similar puncturing type of rate matching used for the first transmissions. For instance, if the first type of rate matching is puncturing, the second type of rate matching may be constrained to be block puncturing or 2-block puncturing. Alternatively, if the first type of rate matching is shortening, the second type of rate matching may be constrained to be block shortening or 2-block shortening.

Additionally or alternatively, the transmitting device may determine the second type of rate matching based on a difference in signal-to-noise (SNR) between the first transmission and the retransmission. For instance, if the difference in SNR between the first transmission and the retransmission is above an SNR threshold, the second type of rate matching may be 2-block puncturing or 2-block shortening and if the difference in SNR is below the SNR threshold, the second type of rate matching may be block puncturing or block shortening. Additionally or alternatively, the transmitting device may determine the second type of rate matching based on a code rate difference between the first transmission and the retransmission. For instance, if the difference in code rate is greater than a threshold, the second type of rate matching may be block puncturing or block shortening, and if the difference in code rate is smaller than the threshold, the second type of rate matching may be 2-block puncturing or 2-block shortening. In some cases, the transmitting device may determine the second type of rate matching based on receiving a NACK from the receiving device. For instance, the transmitting device may determine the second type of rate matching after receiving the NACK.

FIG. 3 illustrates an example of an encoding scheme 300 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, encoding scheme 300 may implement aspects of wireless communications system 100 and device 200. For instance, encoding scheme 300 may be an example of an encoder 210 as described with reference to FIG. 2 and may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1.

A transmitting device (e.g., a UE 115 or a base station 105) performing a first transmission of a code block may encode a first set of information bits 310 to generate a first codeword 325-a. For instance, the transmitting device may map each information bit 310-a, 310-b, 310-c, 310-d, and 310-e to one of bit channels 305-a of a polar coding network 315-a (e.g., mapping frozen bits to any additional bit channels 305-a) to generate codeword 325-a. Codeword 325-a and unencoded bit channel 305-a may have a relationship given by X ₁ = U ₁G _N, where X ₁ may represent a bit vector for codeword 325-a, U ₁ may represent a bit vector for bit channels 305-a, and G _N may represent the polar coding network 315-a. X ₁ and U ₁ may haveN information bits and G _N may have a size of N*N (e.g., N rows and N columns) . In some cases, the transmitting device may not use exclusive or (XOR) stage 320 for the first transmission and codeword 325-b may not be generated for the first transmission.

In some cases, codeword 325-a may be punctured. Puncturing codeword 325-a may involve truncating one or more bits 330 from an end of codeword 325-a. The punctured bits 330 may be punctured from an end corresponding to the start of decoding order 335 (e.g. block puncturing) . Additionally or alternatively, codeword 325-a may be shortened by puncturing bits from an end corresponding to the end of decoding order 335 (not shown) .

If the transmitting device receives a NACK from a receiving device after transmitting the transmission containing codeword 325-a, the transmitting device may perform a retransmission for the information bits 310. Performing the retransmission may involve generating codeword 325-b based on the original information bits 310 and a second polar coding network 315-a. For instance, codeword 325-a and bit channels 305-a may again have a relationship given by X ₁ = U ₁G _N, where X ₁ may represent a bit vector for codeword 325-a, U ₁ may represent a bit vector for bit channels 305-a, and G _N may represent the polar coding network.

Codeword 325-b may be generated, meanwhile, based on bit channels 305-a, bit channels 305-b, polar coding network 315-a, polar coding network 315-b, and XOR stage 320. For instance, codeword 325-b may be formed by passing bit channels 305-athrough polar coding network 315-a, passing bit channels 305-b through polar coding network 315-b, and passing the outputs of polar coding network 315-a and 315-b through XOR stage 320. In one example, codeword 325-b may be determined as

where X ₂ may represent a bit vector for codeword 325-b and U ₂ may represent a bit vector for bit channels 305-b. X ₂ and U ₂ may each have N bits.

Taken together, polar coding network 315-a, polar coding network 315-b, and XOR stage 320 may form polar coding network 315-c. If bit channels U ₁ and U ₂ are treated as a single bit channel vector U (e.g., one is directly appended on the other) and bit vectors X ₁ and X ₂ are treated as a single vector X (e.g., one is directly appended on the other in the same fashion as U ₁ and U ₂) , the relationship between X and U may be given by X = U*G _2N, where G _2N may represent polar coding network 315-c and may have a size of G _2N*G _2N.

In some cases, the reliability of bit channels 305-c may have a different order than bit channels 305-a, and in some cases one or more of bit channels 305-b may have greater reliability than one or more of bit channels 305-a within bit channels 305-c. In these cases, one or more information bits 310 may be relocated or copied from a channel of bit channels 305-a to another channel of bit channels 305-b. For example, in the information bit 310-b may be relocated or copied over to a bit channel within bit channels 305-b. Relocating or copying information bits to bit channels having higher reliability for bit channels 305-c may improve the decoding performance for codewords 325-a and 325-b. In some cases, codewords 325-a and 325-b may undergo block puncturing, and in some cases the bit channel assignment for information bits 310 to bit channels 305 may be an IAA based construction. Block puncturing may involve transmitting some or all of the punctured bits of codeword 325-a, as well as some of codeword 325-b, where bits of codeword 325-a and codeword 325-b that are transmitted are contiguous. A more detailed description of block puncturing may be described with regards to FIGs. 5, 6, and 8.

In some cases, codeword 325-a and 325-b may undergo block shortening, and in some cases the bit channel assignment for information bits 310 to bit channels 305 may be an IAA based construction. Block shortening may involve puncturing known bits of codeword 325-a325-b, and may thus involve transmission of a contiguous set of bits of codewords 325-a and 325-b. In some cases, block shortening may involve the punctured bit length of the second codeword being greater than the punctured bit length of the first codeword (e.g., greater than or equal to N) . A more detailed description of block shortening may be described with regards to FIGs. 7 and 8.

In some cases, codewords 325-a and 325-b may undergo 2-block puncturing, and in some cases the bit channel assignment for information bits 310 to bit channels 305 may be a GA based construction. 2-block puncturing may involve puncturing codeword 325-b in the same fashion as the first codeword 325-a, which may involve transmission of non-contiguous bit channels of codewords 325-a and 325-b. A more detailed description of 2-block puncturing may be described with reference to FIGs. 9 and 12.

In some cases, codewords 325-a and 325-b may undergo 2-block shortening, and in some cases the bit channel assignment for information bits 310 to bit channels 305 may be a GA based construction. 2-block shortening may involve puncturing or shortening codeword 325-ain the same fashion as the first transmission, which may involve transmission of non-contiguous bit channels of codewords 325-a and 325-b. A more detailed description of 2-block shortening may be described with reference to FIGs. 10, 11, and 12.

FIG. 4 illustrates an example of a rate matching decision scheme 400 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, rate matching decision scheme 400 may be implemented by aspects of wireless communications system 100. For instance, the rate matching decision scheme 400 may be implemented by a transmitting device and a receiving device, either or both of which may be a UE 115 or a base station 105 as described with reference to FIG. 1.

At 405, the transmitting device may determine a type of rate matching for the first transmission. The transmitting device may determine the type of rate matching based on the code rate for the first transmission. For instance, if the code rate is above a threshold, the transmitting device may determine the type of rate matching to be shortening and may proceed to 410-b. At 410-b, the transmitting device may perform shortening on the codeword to be transmitted. If the code rate is below the threshold, the transmitting device may determine the type of rate matching to be puncturing and may proceed to 410-a. At 410-a, the transmitting device may perform puncturing on the codeword to be transmitted.

If the first transmission is successfully decoded by the receiving device (e.g., if the transmitting device receives an acknowledgement (ACK) from the receiving device) , the transmitting device may return to 405. If the first transmission is not successfully decoded, the transmitting device may prepare a retransmission for the receiving device. In some examples, if puncturing was used for the first transmission at 410-a, the transmitting device may choose between block puncturing or 2-block puncturing. The transmitting device may choose block puncturing or 2-block puncturing based on a difference in SNR between the first transmission and the retransmission and/or a rate difference (e.g., M ₁ vs. M ₂, as described with reference to FIGs. 5–12) between the first transmission and the retransmission. In one example, if the SNR imbalance is above an SNR threshold, the transmitting device may select 2-block puncturing at 415-b and, if the SNR imbalance is below the SNR threshold, the transmitting device may select block puncturing at 415-a. In another example, if the rate difference is above a code rate threshold, the transmitting device may select block puncturing at 415-a and, if the rate difference is below the code rate threshold, the transmitting device may select 2-block puncturing at 415-b. In some examples, in addition to selecting block puncturing or 2-block puncturing from puncturing at 410-a, the transmitting device may choose 2-block shortening at 415-d. A transmission scheme including 410-a and 415-a may be described with reference FIG. 5, a transmission scheme including 410-a and 415-b may be described with reference to FIG. 9, and a transmission scheme including 410-a and 415-d may be described with reference to FIG. 11.

Alternatively, if at 410-b, in some cases the transmitting device may choose between shortening at 415-c or 2-block shortening at 415-d. The transmitting device may choose block shortening or 2-block shortening based on a difference in SNR between the first transmission and the retransmission and/or a rate difference between the first transmission and the retransmission. In one example, if the SNR imbalance is above an SNR threshold, the transmitting device may proceed to 415-d and, if the SNR imbalance is above an SNR threshold, the transmitting device may proceed to 415-c. In another example, if the rate difference is above a code rate threshold, the transmitting device may proceed to 415-c and, if the rate difference is below the code rate threshold, the transmitting device may proceed to 415-d. In some cases, the transmitting device may additionally choose block puncturing at 415-a from shortening 410-b. A transmission scheme including 410-b and 415-a may be described with reference FIG. 6, a transmission scheme including 410-b and 415-c may be described with reference to FIG. 7, and a transmission scheme including 410-b and 415-d may be described with reference to FIG. 10.

FIG. 5 illustrates an example of a block puncturing scheme 500 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, block puncturing scheme 500 may be implemented by aspects of wireless communications system 100. For instance, block puncturing scheme 500 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1. A transmitting device may implement block puncturing scheme 500 if the transmitting device selects a transmission scheme including 410-a and 415-a when implementing rate matching decision scheme 400.

Block puncturing may generally be a method of contiguous puncturing for a second transmission (e.g., a retransmission) based on a first transmission. For instance, block puncturing may be performed under the assumption that a first set of bits associated with the first transmission are contiguous with a second set of bits associated with the second transmission. In general, the construction of a polar code (e.g., information bit channels) for block puncturing may be IAA for both the first and second transmission. Block puncturing may have a simplified and formulated construction, may have flexibility to different transmission bit lengths for different transmissions, may have increased performance as code rate decreases, and may have extension to multiple types of transmissions.

A transmitting device (e.g., a UE 115 or base station 105) may determine there are D ₁ information bits to encode, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may map the D ₁ information bits to U-domain allocation K ₁ 510. The remaining bits of U-domain allocation K ₁ 510, if any, may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 510 (e.g., N ₁-size (K ₁) bits) to 0. In general, the set of U-domain allocation K ₁ 510 containing the D ₁ information bits may be referred to as K _{1_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₁ 520 based on the U-domain allocation K ₁ 510 and an effective G matrix G ₁ 530. For instance, M ₁ 520 may equal K ₁*G ₁. Any bits in the X-domain outside of X-domain transmitted bits M ₁ 520 (e.g., N ₁-size (M ₁) bits) may be punctured before transmission. The code rate for the transmission may be equal to D ₁/size (M ₁) .

After transmitting the first transmission, the transmitting device may receive a NACK from a receiving device (e.g., a UE 115 or a base station 105) . Upon receiving the NACK, the transmitting device may determine to transmit a second transmission (e.g., a retransmission of the first transmission) . For the second transmission, the transmitting device may relocate a number of bits (e.g., any of the D ₁ information bits in U-domain allocation K ₁ 510) from the U-domain allocation K ₁ 510 to U-domain allocation K ₂ 515, which may be adjacent to U-domain allocation K ₁ 510. The number of bits from the D ₁ information bits that are relocated may be referred to as D ₂. Any bits in U-domain allocation K ₂ 515 not corresponding to relocated bits may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 510 and U-domain allocation K ₂ 515 (e.g., N ₂-size (K ₁) -size (K ₂) U-domain bit channels) to 0. In general, the set of U-domain allocation K ₂ 515 containing the D ₂ information bits may be referred to as K _{2_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₂ 525 based on the U-domain allocation K ₁ 510, the U-domain allocation K ₂ 515, and the effective G matrix G ₂ 535. For instance, the transmitting device may determine X-domain transmitted bits M 540, where M may equal K*G ₂. M may be the combined X-domain transmitted bits M ₂ 525 and M ₁ 520, and K 545 may be the combined U-domain allocation of K ₁ 510 and K ₂ 515. X-domain transmitted bits M ₂ 525 for the second transmission may be a subset of X-domain transmitted bits M 540 not including X-domain transmitted bits M ₁ 520. Any bits in the X-domain outside of X-domain transmitted bits M 540 (e.g., N ₂-size (M) bits) may be punctured before transmission of M ₂ 525. The code rate for the second transmission may be understood as D ₁/size (M ₂) and the code rate for the combined transmission of M ₂ 525 and M ₁ 520 may be equal to D ₁/ (size (M) ) , where D ₁ is understood to include the number of bits relocated to D ₂.

FIG. 6 illustrates an example of a block shortening/puncturing scheme 600 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, block shortening/puncturing scheme 600 may be implemented by aspects of wireless communications system 100. For instance, block shortening/puncturing scheme 600 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1. A transmitting device may implement block shortening/puncturing scheme 600 if the transmitting device selects a transmission scheme including shortening 410-b and block puncturing 415-a when implementing rate matching decision scheme 400.

As mentioned above, block puncturing may generally be a method of contiguous puncturing for a second transmission (e.g., a retransmission) based on a first transmission. For instance, block puncturing may be performed under the assumption that a first set of bits associated with the first transmission are adjacent to a second set of bits associated with the second transmission. In general, the construction of block shortening/puncturing may be IAA for both the first and second transmission.

A transmitting device (e.g., a UE 115 or base station 105) may determine there are D ₁ information bits to encode, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may map the D ₁ information bits to U-domain allocation K ₁ 610. The remaining bits of U-domain allocation K ₁ 610, if any, may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 610 (e.g., N ₁-size (K ₁) bits) to 0. In general, the set of U-domain allocation K ₁ 610 containing the D ₁ information bits may be referred to as K _{1_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₁ 620 based on the U-domain allocation K ₁ 610 and an effective G matrix G ₁ 630. For instance, M ₁ 620 may equal K ₁*G ₁. Any bits in the X-domain outside of X-domain transmitted bits M ₁ 620 (e.g., N ₁-size (M ₁) bits) may be shortened before transmission. The code rate for the transmission may be equal to D ₁/size (M ₁) .

After transmitting the first transmission, the transmitting device may receive a NACK from a receiving device (e.g., a UE 115 or a base station 105) . Upon receiving the NACK, the transmitting device may determine to transmit a second transmission (e.g., a retransmission of the first transmission) . For the second transmission, the transmitting device may relocate a number of bits (e.g., any of the D ₁ information bits in U-domain allocation K ₁ 610) from the U-domain allocation K ₁ 610 to U-domain allocation K ₂ 615, which may be adjacent to U-domain allocation K ₁ 610. The number of the relocated bits corresponding to the D ₁ information bits may be referred to as D ₂. Any bits in U-domain allocation K ₂ 615 not corresponding to relocated bits may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 610 and U-domain allocation K ₂ 615 (N ₂-size (K ₁) -size (K ₂) bits) to 0. In general, the set of U-domain allocation K ₂ 615 containing the D ₂ information bits may be referred to as K _{2_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₂ 625 based on the U-domain allocation K ₁ 610, the U-domain allocation K ₂ 615, and the effective G matrix G ₂ 635. For instance, the transmitting device may determine X-domain transmitted bitsM 640, where M may equal K*G ₂·M may be the combined X-domain transmitted bits M ₂ 625 and M ₁ 620, and K 645 may be the combined U-domain allocation of K ₁ 610 and K ₂ 615. X-domain transmitted bits M ₂ 625 may be a subset of X-domain transmitted bits M 640 excluding X-domain transmitted bits M ₁ 620. The transmitting device may transmit M ₂ 625 in the second transmission, and thus bits in the X-domain outside of X-domain transmitted bits M 640 (e.g., N ₂-size (M) bits) may be shortened (e.g., the bits extending to the right of X-domain transmitted bits M ₁ 620) or punctured (e.g., the bits extending to the left of X-domain transmitted bits M ₂ 625) before transmission. The code rate for the second transmission may be understood as D ₁/size (M ₂) , and the code rate for the combined transmission may be equal to D ₁/ (size (M) ) where D ₁ is understood to include the number of bits relocated to D ₂.

FIG. 7 illustrates an example of a block shortening scheme 700 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, block shortening scheme 700 may be implemented by aspects of wireless communications system 100. For instance, block shortening scheme 700 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1. A transmitting device may implement block shortening scheme 700 if the transmitting device selects a transmission scheme including shortening 410-b and block shortening 415-c when implementing rate matching decision scheme 400.

Block shortening may generally be a method of contiguous shortening for a second transmission (e.g., a retransmission) based on a first transmission. For instance, block shortening may be performed under the assumption that a first set of bits associated with the first transmission are adjacent to a second set of bits (e.g., one or more relocated or copied bits) associated with the second transmission. In general, the construction of block shortening may be IAA for both the first and second transmission. Block shortening may have a simplified and formulated construction and may have better performance than puncturing for the first transmission as code rate increases.

A transmitting device (e.g., a UE 115 or base station 105) may determine there are D ₁ information bits to encode, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may map the D ₁ information bits to U-domain allocation K ₁ 710. The remaining bits of U-domain allocation K ₁ 710, if any, may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 710 (e.g., N ₁-size (K ₁) bits) to 0. In general, the set of U-domain allocation K ₁ 710 containing the D ₁ information bits may be referred to as K _{1_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₁ 720 based on the U-domain allocation K ₁ 710 and an effective G matrix G ₁ 730. For instance, M ₁ 720 may equal K ₁*G ₁. Any bits in the X-domain outside of X-domain transmitted bits M ₁ 720 (e.g., N ₁-size (M ₁) bits) may be punctured before transmission. The code rate for the transmission may be equal to D ₁/size (M ₁) .

After transmitting the first transmission, the transmitting device may receive a NACK from a receiving device (e.g., a UE 115 or a base station 105) . Upon receiving the NACK, the transmitting device may determine to transmit a second transmission (e.g., a retransmission of the first transmission) . For the second transmission, the transmitting device may relocate a number of bits (e.g., any of the D ₁ information bits in U-domain allocation K ₁ 710) from the U-domain allocation K ₁ 710 to U-domain allocation K ₂ 715, which may be adjacent to U-domain allocation K ₁ 710. The number of the relocated bits corresponding to the D ₁ information bits may be referred to as D ₂. Any bits in U-domain allocation K ₂ 715 not corresponding to relocated bits may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 710 and U-domain allocation K ₂ 715 to 0. In general, the set of U-domain allocation K ₂ 715 containing the D ₂ information bits may be referred to as K _{2_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₂ 725 based on the U-domain allocation K ₁ 710, the U-domain allocation K ₂ 715, and the effective G matrix G ₂ 735. For instance, the transmitting device may determine X-domain transmitted bits M 740, where M may equal K*G ₂· M may be the combined X-domain transmitted bits M ₂ 725 and M ₁ 720, and K 745 may be the combined U-domain allocation of K ₁ 710 and K ₂ 715. X-domain transmitted bits. The transmitting device may transmit X-domain transmitted bits M ₂ 725 in the second transmission. As illustrated in FIG. 7, the X-domain transmitted bits M ₂ 725 for the second transmission may not be shortened. Thus, in some examples, size (M ₂) may be greater than or equal to N2-N ₁, which may also be greater than size (M ₁) .The size of M ₂ 725 for implementing block shortening may be a drawback of this scheme relative to other schemes. The code rate for the second transmission may be understood as D ₁/size (M ₂) , and the code rate for the combined transmission may be equal to D ₁/(size (M) ) ,where D ₁ is understood to include the number of bits relocated to D ₂.

FIG. 8 illustrates an example of a block puncturing construction scheme 800 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, block puncturing construction scheme 800 may be implemented by aspects of wireless communications system 100. For instance, block puncturing construction scheme 800 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1. Block puncturing construction scheme 800 may be implemented when a transmitting device is implementing block puncturing scheme 500, block shortening/puncturing scheme 600, block shortening scheme 700, or a combination thereof. It should be noted that block puncturing construction scheme 800 may be modified to implement a block shortening construction scheme, as described below.

Initially a transmitting device (e.g., a UE 115 or base station 105) may determine that there are D ₁ information bits 810 to encode for a first transmission, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may perform IAA for the first transmission, where D ₁, a code rate M ₁, and a total domain size N ₁ may be the inputs for IAA. Upon performing IAA, the transmitting device may determine a U-domain information location vector for the first transmission. In one case, the U-domain information location vector may represent a whole U-domain allocation K ₁ 815 (e.g., both frozen bits and information bits 810) . In another case, the U-domain information location vector may represent the portions of U-domain allocation K ₁ 815 allocated to the D ₁ information bits 810, which may be referred to as K _{1_info}. In such a case, the U-domain information location vector may have a size of D ₁. In either case, the D ₁ information bits 810 may be mapped to D ₁ entries of the U-domain information location vector. For example, the D ₁ information bits (e.g., including first transmission information bit #1 810-a and first transmission information bit #2 810-b) may be mapped to D ₁ bit channels, such as shown in U-domain bit mapping 805-a. Mapping may involve splitting some of the D ₁ information bits 810 to be in an upper

domain 830 (e.g., first transmission information bit #1 810-a and first transmission information bit #2 810-b) and splitting the rest of the D ₁ information bits 810 to be in a lower

domain 835. For a block puncturing construction scheme, the U-domain allocation K ₁ 815 may extend from an end in the lower

domain 835 and, for a block shortening construction scheme, the U-domain allocation K ₁ 815 may extend from an opposing end in the upper

domain 830.

If the transmitting device determines to perform a retransmission (e.g., upon reception of a NACK) , the transmitting device may perform IAA again, where the inputs may be D ₁, a combined code rate M ₁+M ₂, and a total domain size N ₂. Upon performing IAA, the transmitting device may determine a U-domain information location vector for the second transmission. In one case, the U-domain information location vector may represent a whole U-domain allocation K′ ₂ 820 (e.g., both frozen bits and information bits 810) . In another case, the U-domain information location vector may represent the portions of the U-domain allocation K′ ₂ 820 allocated to the D ₁ information bits 810, which may be referred to as K′ _{2_info}. In such a case, the U-domain information location vector may have a size of D ₁.

In some examples, the transmitting device may relocate one or more information bits based on a difference between the U-domain information location vector for the first transmission and the U-domain information location vector for the second transmission. If the U-domain location vector for the first transmission represents the whole U-domain allocation K ₁ 815 and the U-domain location vector for the second transmission represents the whole U-domain allocation K′ ₂ 820, the transmitting device may compare K ₁ 815 and K′ ₂ 820 to obtain U-domain allocation K ₂ 825. If the U-domain location vector for the first transmission represents K _{1_info} and the U-domain location vector for the second transmission represents K′ _{2_info}, the transmitting device may compare K _{1_info} and K′ _{2_info} to obtain K _{2_info}, which may represent the portion of U-domain allocation K ₂ 820 allocated to information bits 810 (e.g., including second transmission information bit #1 810-c and second transmission information bit #2 810-d) .

Upon obtaining K ₂ 825 and/or K _{2_info}, the transmitting device may determine which information bits 810 in K ₁ 815 or K _{1_info} correspond to the information bits 810 in U-domain allocation K ₂ 825 or K _{2_info}. For instance, second transmission information bit #1 810-c may correspond to first transmission information bit #1 810-a and second transmission information bit #2 810-d may correspond to first transmission information bit #2 810-b. As such, second transmission information bit #1 810-c and second transmission information bit 810-d may be referred to as relocated information bits.

An example of a U-domain allocation K′ ₂ 820 may be demonstrated with regards to U-domain bit-channel mapping 805-b and an example of the differentiation process to obtain U-domain allocation K ₂ 825 may be demonstrated with regards to U-domain bit-channel mapping 805-c. After performing the mapping, the transmitting device may perform polar encoding for U-domain allocations K ₁ 815 and K ₂ 825 and may prepare a second transmission including the encoded information bits, as demonstrated with regards to FIGs. 5–7 (e.g., X-domain bits M ₂) . For a block puncturing construction scheme, U-domain allocation K ₁ 815 may extend from an end in a lower

domain 845 and, for a block shortening construction scheme, U-domain allocation K′ ₂ 820 overlapping U-domain allocation K ₁ 815 may extend from the other end in the lower

domain 845. Additionally, for a block shortening construction scheme, U-domain allocation K ₂ 825 may span an entire upper

domain 840.

FIG. 9 illustrates an example of a 2-block puncturing scheme 900 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, 2-block puncturing scheme 900 may be implemented by aspects of wireless communications system 100. For instance, 2-block puncturing scheme 900 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1. A transmitting device may implement 2 block puncturing scheme 900 if the transmitting device selects a transmission scheme including puncturing 410-a and 2-block puncturing 415-b when implementing rate matching decision scheme 400.

2-block puncturing may generally be a method of non-contiguous puncturing for a second transmission (e.g., a retransmission) based on a first transmission. For instance, 2-block puncturing may be performed under the assumption that a first set of bits associated with the first transmission are not adjacent to a second set of associated with the second transmission. In general, the construction of 2-block puncturing may be IAA for the first transmission and GA (e.g., GA with a first order approximation) for the second transmission. In general, a mother code length for each part may be equal, which may enable simplified construction. Using 2-block puncturing may enable the second transmission to be self-decodable and may allow flexibility for SNR dependent code construction.

A transmitting device (e.g., a UE 115 or base station 105) may determine there are D ₁ information bits to encode, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may map the D ₁ information bits to U-domain allocation K ₁ 910. The remaining bits of U-domain allocation K ₁ 910, if any, may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 910 (e.g., N ₁-size (K ₁) bits) to 0. In general, the set of U-domain allocation K ₁ 910 containing the D ₁ information bits may be referred to as K _{1_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₁ 920 based on the U-domain allocation K ₁ 910 and an effective G matrix G ₁ 930. For instance, M ₁ 920 may equal K ₁*G ₁. Any bits in the X-domain outside of X-domain transmitted bits M ₁ 920 (e.g., N ₁-size (M ₁) bits) may be punctured before transmission. The code rate for the transmission may be equal to D ₁/size (M ₁) .

After transmitting the first transmission, the transmitting device may receive a NACK from a receiving device (e.g., a UE 115 or a base station 105) . Upon receiving the NACK, the transmitting device may determine to transmit a second transmission (e.g., a retransmission of the first transmission) . For the second transmission, the transmitting device may relocate a number of bits (e.g., one or more of the D ₁ information bits in U-domain allocation K ₁ 910) from the U-domain allocation K ₁ 910 to U-domain allocation K ₂ 915, which may not be adjacent to U-domain allocation K ₁ 910. The number of the relocated bits corresponding to the D ₁ information bits may be referred to as D ₂. Any bits in U-domain allocation K ₂ 915 not corresponding to relocated bits may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 910 and U-domain allocation K ₂ 915 (e.g., N ₂-size (K ₁) -size (K ₂) bits) to 0. In general, the set of U-domain allocation K ₂ 915 containing the D ₂ information bits may be referred to as K _{2_info} and may be represented by a U-domain information location bit vector.

The transmitting device may determine X-domain transmitted bits M ₂ 925 based on the U-domain allocation K ₁ 910, the U-domain allocation K ₂ 915, and the effective G matrices G _{2_bot} 935 and G _{2_top} 940. For instance, M ₂ may be equal to

It should be noted that in some cases

The transmitting device may transmit X-domain transmitted bits M ₂ in the second transmission. Any bits in the X-domain outside of X-domain transmitted bits M ₁ and M ₂ may be punctured before transmission. The code rate for the second transmission may be understood as D ₁/size (M ₂) , and the code rate for the combined transmission may be equal to D ₁/ (size (M ₁) +size (M ₂) ) , where D ₁ is understood to include the number of bits relocated to D ₂.

FIG. 10 illustrates an example of a 2-block shortening scheme 1000 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, 2-block shortening scheme 1000 may be implemented by aspects of wireless communications system 100. For instance, 2-block shortening scheme 1000 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1. A transmitting device may implement 2 block shortening scheme 1000 if the transmitting device selects a transmission scheme including shortening 410-b and 2-block shortening 415-d when implementing rate matching decision scheme 400.

2-block shortening may generally be a method of non-contiguous shortening for a second transmission (e.g., a retransmission) based on a first transmission. For instance, 2-block shortening may be performed under the assumption that a first set of bits associated with the first transmission are not adjacent to a second set of bits (e.g., one or more relocated or copied bits) associated with the second transmission. In general, the construction of 2-block shortening may be IAA for the first transmission and GA (e.g., GA with a first order approximation) for the second transmission. In general, a mother code length for each part may be equal, which may enable simplified construction. Using 2-block shortening may enable the second transmission to be self-decodable and may allow flexibility for SNR dependent code construction.

A transmitting device (e.g., a UE 115 or base station 105) may determine there are D ₁ information bits to encode, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may map the D ₁ information bits to U-domain allocation K ₁ 1010. The remaining bits of U-domain allocation K ₁ 1010, if any, may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 1010 (e.g., N ₁-size (K ₁) bits) to 0.

The transmitting device may determine X-domain transmitted bits M ₁ 1020 based on the U-domain allocation K ₁ 1010 and an effective G matrix G ₁ 1030. For instance, M ₁ 1020 may equal K ₁*G ₁. Any bits in the X-domain outside of X-domain transmitted bits M ₁ 1020 (e.g., N ₁-size (M ₁) bits) may be punctured before transmission. The code rate for the transmission may be equal to D ₁/size (M ₁) In general, the set of U-domain allocation K ₁ 1010 containing the D ₁ information bits may be referred to as K _{1_info} and may be represented by a U-domain information location bit vector.

After transmitting the first transmission, the transmitting device may receive a NACK from a receiving device (e.g., a UE 115 or a base station 105) . Upon receiving the NACK, the transmitting device may determine to transmit a second transmission (e.g., a retransmission of the first transmission) . For the second transmission, the transmitting device may relocate a number of bits (e.g., any of the D ₁ information bits in U-domain allocation K ₁ 1010) from the U-domain allocation K ₁ 1010 to U-domain allocation K ₂ 1015, which may not be adjacent to U-domain allocation K ₁ 1010. The number of the relocated bits corresponding to the D ₁ information bits may be referred to as D ₂. Any bits in U-domain allocation K ₂ 1015 not corresponding to relocated bits may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 1010 and U-domain allocation K ₂ 1015 (N ₂-size (K ₁) -size (K ₂) bits) to 0.

The transmitting device may determine X-domain transmitted bits M ₂ 1025 based on the U-domain allocation K ₁ 1010, the U-domain allocation K ₂ 1015, and the effective G matrices G _{2_bot} 1035 and G _{2_top} 1040. For instance, M ₂ may be equal to

It should be noted that in some cases

The transmitting device may transmit the X-domain transmitted bits M ₂ in the second transmission. Any bits in the X-domain outside of X-domain transmitted bits M ₁ and M ₂ may be shortened before transmission. The code rate for the second transmission may be understood as D ₁/size (M ₂) , and the code rate for the combined transmission may be equal to D ₁/ (size (M ₁) +size (M ₂) ) , where D ₁ is understood to include the number of bits relocated to D ₂. In general, the set of U-domain allocation K ₂ 1015 containing the D ₂ information bits may be referred to as K _{2_info} and may be represented by a U-domain information location bit vector.

FIG. 11 illustrates an example of a puncturing/2-block shortening scheme 1100 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, puncturing/2-block shortening scheme 1100 may implement aspects of wireless communications system 100. For instance, puncturing/2-block shortening scheme 1100 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1. A transmitting device may implement puncturing/2-block shortening scheme 1100 if the transmitting device selects a transmission scheme including puncturing 410-a and 2-block shortening 415-d when implementing rate matching decision scheme 400.

A transmitting device (e.g., a UE 115 or base station 105) may determine there are D ₁ information bits to encode, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may map the D ₁ information bits to U-domain allocation K ₁ 1110. The remaining bits of U-domain allocation K ₁ 1110, if any, may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 1110 (e.g., N ₁-size (K ₁) bits) to 0.

The transmitting device may determine X-domain transmitted bits M ₁ 1120 based on the U-domain allocation K ₁ 1110 and an effective G matrix G ₁ 1130. For instance, M ₁ 1120 may equal K ₁*G ₁. Any bits in the X-domain outside of X-domain transmitted bits M ₁ 1120 (e.g., N ₁-size (M ₁) bits) may be punctured before transmission. The code rate for the transmission may be equal to D ₁/size (M ₁) In general, the set of U-domain allocation K ₁ 1110 containing the D ₁ information bits may be referred to as K _{1_info} and may be represented by a U-domain information location bit vector.

After transmitting the first transmission, the transmitting device may receive a NACK from a receiving device (e.g., a UE 115 or a base station 105) . Upon receiving the NACK, the transmitting device may determine to transmit a second transmission (e.g., a retransmission of the first transmission) . For the second transmission, the transmitting device may relocate a number of bits (e.g., any of the D ₁ information bits in U-domain allocation K ₁ 1110) from the U-domain allocation K ₁ 1110 to U-domain allocation K ₂ 1115, which may not be adjacent to U-domain allocation K ₁ 1110. The number of the relocated bits corresponding to the D ₁ information bits may be referred to as D ₂. Any bits in U-domain allocation K ₂ 1115 not corresponding to relocated bits may be set as frozen bits. The transmitting device may set any bits outside of the U-domain allocation K ₁ 1110 and U-domain allocation K ₂ 1115 (N ₁-size (K ₁) bits and N ₂-N ₁-size (K ₂) bits) to 0.

The transmitting device may determine X-domain transmitted bits M ₂ 1125 based on the U-domain allocation K ₁ 1110, the U-domain allocation K ₂ 1115, and the effective G matrices G _{2_top} 1135 and G _{2_bot}. For instance, M ₂ may be equal to

It should be noted that in some cases

The transmitting device may transmit the X-domain transmitted bits M ₂ in the second transmission. Any bits in the X-domain outside of X-domain transmitted bits M ₁ and M ₂ may be shortened or punctured before transmission. The code rate for the second transmission may be understood as D ₁/size (M ₂) , and the code rate for the combined transmission may be equal to D ₁/ (size (M ₁) +size (M ₂) ) where D ₁ is understood to include the number of bits relocated to D ₂. In general, the set of U-domain allocation K ₂ 1115 containing the D ₂ information bits may be referred to as K _{2_info} and may be represented by a U-domain information location bit vector.

FIG. 12 illustrates an example of a 2-block puncturing construction scheme 1200 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, 2-block puncturing construction scheme 1200 may be implemented by aspects of wireless communications system 100. For instance, 2-block puncturing construction scheme 1200 may be implemented by a UE 115 or a base station 105 as described with reference to FIG. 1.2-block puncturing construction scheme 1200 may be implemented when a transmitting device is implementing 2-block puncturing scheme 900, 2-block shortening scheme 1000, puncturing/2-block shortening scheme 1100, or a combination thereof. It should be noted that 2-block puncturing construction scheme 1200 may be modified to implement a 2-block shortening scheme as described below.

Initially a transmitting device (e.g., a UE 115 or base station 105) may determine that there are D ₁ information bits 1210 to encode for a first transmission, where D ₁ may be equal to a sum of A ₁ payload bits and E ₁ parity or error checking bits. The transmitting device may perform IAA for the first transmission, where D ₁, a code rate M ₁, and a total domain size N ₁ may be the inputs for IAA. Upon performing IAA, the transmitting device may determine a U-domain information location vector for the first transmission. In one case, the U-domain information location vector may represent a whole U-domain allocation K ₁ 1215 (e.g., both frozen and information bits 1210) . In another case, the U-domain information location vector may represent the portions of U-domain allocation K ₁ 1215 allocated to the D ₁ information bits 1210, which may be referred to as K _{1_info}. In such a case, the U-domain information location vector may have a size of D ₁. In either case, the D ₁ information bits 1210 may be mapped to D ₁ entries of the U-domain information location vector. For example, the D ₁ information bits (e.g., including first transmission information bit #1 1210-a and first transmission information bit #2 1210-b) may be mapped to D ₁ bit-channels, such as shown in U-domain bit mapping 1205-a. Mapping may involve splitting some of the D ₁ information bits 1210 to be in an upper

domain 1225 of U-domain bit channel mapping 1205-a and splitting the rest of the D ₁ information bits 1210 to be in a lower

domain 1230 of U-domain bit channel mapping 1205-a. For a 2-block puncturing construction scheme, the U-domain allocation K ₁ 1215 may extend from an end of the lower

domain 1230 and, for a 2-block shortening construction scheme, the U-domain allocation K ₁ 1215 may extend from an opposing end in the upper

domain 1225.

If the transmitting device determines to perform a retransmission, the transmitting device may determine a number of information bits 1210 for relocation to a U-domain allocation K ₂ 1220 or to the portion of the U-domain allocation K ₂ 1220 allocated to information bits, which may be referred to as K _{2_info}. The transmitting device may determine the based on a calculation based on GA and/or DE. In general, the transmitting device may assume that M ₁=M ₂, which may enable greater construction simplicity. Additionally, the number of relocation bits for U-domain allocation K ₂ 1220 or K _{2_info} may be calculated using a first order approximation of a GA. In some cases, an SNR-imbalance-based construction may be used. An example of U-domain allocation K ₂ 1220 may be demonstrated with regards to U-domain bit-channel mapping 1205-b.

Upon identifying U-domain allocation K ₂ 1220 or K _{2_info} and the number of information bits 1210 to relocate, the transmitting device may determine the location of the information bits 1210 to relocate. For instance, a least reliable information bit 1210 within U-domain allocation K ₁ 1215 or K _{1_info} (e.g., first transmission information bit #1 1210-a) may be relocated to a most reliable information bit 1210 within U-domain allocation K ₂ 1220 or K _{2_info} (e.g., second transmission information bit #1 1210-c) . Then, the next least reliable information bit 1210 within K ₁ 1215 or K _{1_imfo} (e.g., first transmission information bit #2 1210-b) may be relocated to a next most reliable information bit 1210 within K ₂ 1220 or K _{2_info} (e.g., second transmission information bit #2 1210-d) . This process may continue until the determined number of information bits 1210 to relocate have been relocated. Information bits 1210 that are not to be relocated may remain in their former location within U-domain allocation K ₁ 1215 or K _{1_info}. An example of the relocation process may be demonstrated with regards to U-domain bit-channel mapping 1205-c.

After performing the mapping, the transmitting device may perform polar encoding for U-domain allocations K ₁ and K ₂ and may transmit a second transmission containing the encoded information bits, as demonstrated with regards to FIGs. 9–11 (e.g., X-domain bits M ₂) . For a 2-block puncturing construction scheme, the U-domain allocation K ₂ 1220 may extend from a first end of an upper

domain 1235 of the U-domain bit channel mapping 1205-b and, for a 2-block shortening construction scheme, the U-domain allocation K ₂ 1220 may extend from the other end of the upper

domain 1235. Similarly, for a 2-block puncturing construction scheme, the U-domain allocation K ₁ 1215 may extend from a first end of a lower

domain 1240 of the U-domain bit channel mapping 1205-b and, for a 2-block shortening construction scheme, the U-domain allocation K ₁ 1215 may extend from the other end of the lower

domain 1240.

FIG. 13 illustrates an example of a process flow 1300 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. In some examples, process flow 1300 may implement aspects of wireless communications system 100. For instance, process flow 1300 includes a base station 105-a and UE 115-a, which may be examples of a base station 105 or a UE 115 as described with reference to FIG. 1. In some cases, a UE 115 may be substituted for base station 105-a and/or a base station 105 may be substituted for UE 115-a.

At 1302, UE 115-a may transmit a first indication of a signal metric (e.g., an SNR) for a first transmission. The first indication of the signal metric may be CSI, SRSs, or a combination thereof.

At 1305, base station 105-a may transmit a first transmission of a code block. The first transmission may include a first codeword encoded using a first polar code and rate matched using a first type of rate matching. In some cases, base station 105-a may determine the first type of rate matching based on a code rate of the first transmission. For instance, if the code rate is above a code rate threshold, base station 105-a may perform puncturing and, if the code rate is below the code rate threshold, base station 105-a may perform shortening. UE 115-a may receive the first transmission.

At 1310, UE 115-a may transmit a NACK. UE 115-a may transmit the NACK if UE 115-afailed to decode at least a portion of the first transmission. Base station 105-a may receive the NACK.

At 1315, UE 115-a may transmit a second indication of a signal metric (e.g., an SNR) for a second transmission of the code block. The second indications of the signal metric may be CSI, SRSs, or a combination thereof.

At 1320, base station 105-a may determine a second type of rate matching for the second transmission of the code block (e.g., a retransmission) . The second type of rate matching may be one of block puncturing, block shortening, 2-block puncturing, and 2-block shortening. Base station 105-a may determine the second type of rate matching based on a difference in signal metrics (e.g., the signal metrics received at 1315) or code rates between the first transmission and the second transmission. In one example, if the difference in signal metrics is above a signal metric threshold, base station 105-a may determine that the second type of rate matching is 2-block puncturing or 2-block shortening and, if the difference is below the signal metric threshold, base station 105-a may determine that the second type of rate matching is block puncturing or block shortening. In another example, if the difference in code rates is above a code rate threshold, base station 105-a may determine that the second type of rate matching is block puncturing or block shortening and, if the difference is below the code rate threshold, base station 105-a may determine that the second type of rate matching is 2-block puncturing or 2-block shortening.

In some cases, base station 105-a may determine the second type of rate matching based on the first type of rate matching. For example if the first type of rate matching is puncturing, the second type of rate matching may be block puncturing or 2-block puncturing. Alternatively, if the first type of rate matching is shortening, the second type of rate matching may be block shortening or 2-block shortening. Additionally or alternatively, the base station 105-a may employ cross-type rate matching. For example, the base station 105-a may use shortening for a first transmission and block puncturing for a second transmission for a combined scheme corresponding to shortening/block puncturing. Alternatively, the base station 105-a may use puncturing for a first transmission and 2-block shortening for the second transmission for a combined scheme corresponding to puncturing/2-block shortening. Selection of cross-type rate matching may be based on a difference in code rates or difference in signal metrics (e.g., SNRs) between the first transmission and second transmission.

At 1325, base station 105-a may transmit an indication of the second type of rate matching. UE 115-a may receive the indication of the second type of rate matching. In some cases, the indication is transmitted via downlink control information scheduling the second transmission. For example, a field of the downlink control information may indicate whether the retransmission uses adjacent (e.g., block puncturing, block shortening) or non-adjacent X-domain transmitted bits (e.g., 2-block puncturing, 2-block shortening) .

At 1330, base station 105-a may transmit the second transmission of the code block. The second transmission of the code block may include a second codeword encoded using a second polar code and rate matched using the second type of rate matching.

FIG. 14 shows a block diagram 1400 of a device 1405 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The device 1405 may be an example of aspects of a base station 105 or a UE 115 as described herein. The device 1405 may include a receiver 1410, a communications manager 1415, and a transmitter 1420. The device 1405 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1410 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to adaptive rate matching for polar codes, etc. ) . Information may be passed on to other components of the device 1405. The receiver 1410 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The receiver 1410 may utilize a single antenna or a set of antennas.

The communications manager 1415 may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching, transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching, receive a negative acknowledgement message corresponding to the first transmission, and determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission. The communications manager 1415 may be an example of aspects of the communications manager 1710 described herein. The actions performed by the communications manager 1215 as described herein may be implemented to realize one or more potential advantages. One implementation may allow a transmitting device (e.g., a UE 115 or base station 105) to choose, among a set of rate matching schemes, the rate matching scheme associated with a highest likelihood of successful decoding. As such, there may be a smaller probability that another retransmission would be sent and, on average, the latency associated with transmitting the data may be decreased. Another implementation may allow a transmitting device to account for differences in signal metrics and code rates when determining how to rate match data.

The communications manager 1415, or its sub-components, may be implemented in hardware, code (e.g., software or firmware) executed by a processor, or any combination thereof. If implemented in code executed by a processor, the functions of the communications manager 1415, or its sub-components may be executed by a general-purpose processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , a field-programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described in the present disclosure.

The communications manager 1415, or its sub-components, may be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations by one or more physical components. In some examples, the communications manager 1415, or its sub-components, may be a separate and distinct component in accordance with various aspects of the present disclosure. In some examples, the communications manager 1415, or its sub-components, may be combined with one or more other hardware components, including but not limited to an input/output (I/O) component, a transceiver, a network server, another computing device, one or more other components described in the present disclosure, or a combination thereof in accordance with various aspects of the present disclosure.

The transmitter 1420 may transmit signals generated by other components of the device 1405. In some examples, the transmitter 1420 may be collocated with a receiver 1410 in a transceiver module. For example, the transmitter 1420 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The transmitter 1420 may utilize a single antenna or a set of antennas.

FIG. 15 shows a block diagram 1500 of a device 1505 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The device 1505 may be an example of aspects of a device 1405, a base station 105, or a UE 115 as described herein. The device 1505 may include a receiver 1510, a communications manager 1515, and a transmitter 1535. The device 1505 may also include a processor. Each of these components may be in communication with one another (e.g., via one or more buses) .

The receiver 1510 may receive information such as packets, user data, or control information associated with various information channels (e.g., control channels, data channels, and information related to adaptive rate matching for polar codes, etc. ) . Information may be passed on to other components of the device 1505. The receiver 1510 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The receiver 1510 may utilize a single antenna or a set of antennas.

The communications manager 1515 may be an example of aspects of the communications manager 1415 as described herein. The communications manager 1515 may include a codeword transmitter 1520, a NACK receiver 1525, and a rate matching component 1530. The communications manager 1515 may be an example of aspects of the communications manager 1710 described herein.

The codeword transmitter 1520 may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching and transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching.

The NACK receiver 1525 may receive a negative acknowledgement message corresponding to the first transmission.

The rate matching component 1530 may determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission. By basing determining the second type of rate matching on a difference in signal metrics or code rates, the rate matching component 1330 may choose a type of rate matching among a set of types of rate matching with a highest likelihood of successful decoding for the second transmission.

The transmitter 1535 may transmit signals generated by other components of the device 1505. In some examples, the transmitter 1535 may be collocated with a receiver 1510 in a transceiver module. For example, the transmitter 1535 may be an example of aspects of the transceiver 1720 described with reference to FIG. 17. The transmitter 1535 may utilize a single antenna or a set of antennas.

FIG. 16 shows a block diagram 1600 of a communications manager 1605 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The communications manager 1605 may be an example of aspects of a communications manager 1415, a communications manager 1515, or a communications manager 1710 described herein. The communications manager 1605 may include a codeword transmitter 1610, a NACK receiver 1615, a rate matching component 1620, a signal metric component 1625, a signal metric receiver 1630, a code rate component 1635, a bit encoder 1640, and a rate matching indication transmitter 1645. Each of these modules may communicate, directly or indirectly, with one another (e.g., via one or more buses) .

The codeword transmitter 1610 may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching. In some examples, transmitting the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching.

The NACK receiver 1615 may receive a negative acknowledgement message corresponding to the first transmission.

The rate matching component 1620 may determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission. By basing determining the second type of rate matching on a difference in signal metrics or code rates, the communications manager 1605 may choose a type of rate matching among a set of types of rate matching with a highest likelihood of successful decoding for the second transmission. In some examples, the rate matching component 1620 may determine the second type of rate matching for the second transmission based on determining whether the threshold is satisfied. In some examples, the rate matching component 1620 may determine the difference between the first signal metric for the first transmission and the second signal metric for the second transmission based on the received first and second indications. In some examples, the rate matching component 1620 may determine the first type of rate matching based on determining whether the threshold is satisfied. In some examples, the rate matching component 1620 may determine the second type of rate matching for the second transmission is further based on the first type of rate matching. In some cases, the first type of rate matching is puncturing, and where the second type of rate matching is one of block puncturing, 2-block puncturing, block shortening, or 2-block shortening based on the first type of rate matching being puncturing. In some cases, the first type of rate matching is shortening, and where the second type of rate matching is one of block shortening, 2-block shortening, block puncturing, or 2-block puncturing based on the first type of rate matching being shortening.

The signal metric component 1625 may determine whether a difference between a first signal metric for the first transmission and a second signal metric for the second transmission satisfies a threshold. In some cases, the first signal metric for the first transmission and the second signal metric for the second transmission correspond to signal-to-noise ratios for a channel associated with the first and second transmissions.

The signal metric receiver 1630 may receive a first indication of the first signal metric for the first transmission and a second indication of the second signal metric for the second transmission. In some examples, receiving each of the first and second indications includes receiving CSI, a SRS, or a combination thereof.

The code rate component 1635 may determine whether a difference between a first code rate of the first transmission and a second code rate of the second transmission satisfies a threshold. In some examples, the code rate component 1635 may determine whether a code rate associated with the first transmission satisfies a threshold.

The bit encoder 1640 may encode a first set of information bits according to the first polar code to generate a first set of polar-encoded bits. In some examples, encoding a second set of information bits according to the second polar code to generate a second set of polar-encoded bits, where the second set of information bits includes the first set of information bits. In some cases, at least two information bits of the second set of information bits corresponds to one information bit of the first set of information bits. In some cases, the second set of polar-encoded bits includes the first set of polar-encoded bits.

The rate matching indication transmitter 1645 may transmit an indication of the second type of rate matching. In some cases, the indication is transmitted via downlink control information scheduling the second transmission.

FIG. 17 shows a diagram of a system 1700 including a device 1705 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The device 1705 may be an example of or include the components of device 1405, device 1505, a base station 105, or a UE 115 as described herein. The device 1705 may include components for bi-directional voice and data communications including components for transmitting and receiving communications, including a communications manager 1710, a network communications manager 1715, a transceiver 1720, an antenna 1725, memory 1730, a processor 1740, and an inter-station communications manager 1745. These components may be in electronic communication via one or more buses (e.g., bus 1750) .

The communications manager 1710 may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching, transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching, receive a negative acknowledgement message corresponding to the first transmission, and determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission.

The network communications manager 1715 may manage communications with the core network (e.g., via one or more wired backhaul links) . For example, the network communications manager 1715 may manage the transfer of data communications for client devices, such as one or more UEs 115.

The transceiver 1720 may communicate bi-directionally, via one or more antennas, wired, or wireless links as described above. For example, the transceiver 1720 may represent a wireless transceiver and may communicate bi-directionally with another wireless transceiver. The transceiver 1720 may also include a modem to modulate the packets and provide the modulated packets to the antennas for transmission, and to demodulate packets received from the antennas.

In some cases, the wireless device may include a single antenna 1725. However, in some cases the device may have more than one antenna 1725, which may be capable of concurrently transmitting or receiving multiple wireless transmissions.

The memory 1730 may include RAM, ROM, or a combination thereof. The memory 1730 may store computer-readable code 1735 including instructions that, when executed by a processor (e.g., the processor 1740) cause the device to perform various functions described herein. In some cases, the memory 1730 may contain, among other things, a basic input/output system (BIOS) which may control basic hardware or software operation such as the interaction with peripheral components or devices.

The processor 1740 may include an intelligent hardware device, (e.g., a general-purpose processor, a DSP, a CPU, a microcontroller, an ASIC, an FPGA, a programmable logic device, a discrete gate or transistor logic component, a discrete hardware component, or any combination thereof) . In some cases, the processor 1740 may be configured to operate a memory array using a memory controller. In some cases, a memory controller may be integrated into processor 1740. The processor 1740 may be configured to execute computer-readable instructions stored in a memory (e.g., the memory 1730) to cause the device 1705 to perform various functions (e.g., functions or tasks supporting adaptive rate matching for polar codes) .

The inter-station communications manager 1745 may manage communications with other base station 105, and may include a controller or scheduler for controlling communications with UEs 115 in cooperation with other base stations 105. For example, the inter-station communications manager 1745 may coordinate scheduling for transmissions to UEs 115 for various interference mitigation techniques such as beamforming or joint transmission. In some examples, the inter-station communications manager 1745 may provide an X2 interface within an LTE/LTE-Awireless communication network technology to provide communication between base stations 105.

The code 1735 may include instructions to implement aspects of the present disclosure, including instructions to support wireless communications. The code 1735 may be stored in a non-transitory computer-readable medium such as system memory or other type of memory. In some cases, the code 1735 may not be directly executable by the processor 1740 but may cause a computer (e.g., when compiled and executed) to perform functions described herein.

FIG. 18 shows a flowchart illustrating a method 1800 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The operations of method 1800 may be implemented by a base station 105, a UE 115, or their components as described herein. For example, the operations of method 1800 may be performed by a communications manager as described with reference to FIGs. 14 through 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1805, the base station or UE may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching. The operations of 1805 may be performed according to the methods described herein. In some examples, aspects of the operations of 1805 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1805 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1810, the base station or UE may receive a negative acknowledgement message corresponding to the first transmission. The operations of 1810 may be performed according to the methods described herein. In some examples, aspects of the operations of 1810 may be performed by a NACK receiver as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1810 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1815, the base station or UE may determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission. The operations of 1815 may be performed according to the methods described herein. In some examples, aspects of the operations of 1815 may be performed by a rate matching component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1815 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1820, the base station or UE may transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching. The operations of 1820 may be performed according to the methods described herein. In some examples, aspects of the operations of 1820 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1820 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

FIG. 19 shows a flowchart illustrating a method 1900 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The operations of method 1900 may be implemented by a base station 105, a UE 115, or their components as described herein. For example, the operations of method 1900 may be performed by a communications manager as described with reference to FIGs. 14 through 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 1905, the base station or UE may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching. The operations of 1905 may be performed according to the methods described herein. In some examples, aspects of the operations of 1905 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1905 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1910, the base station or UE may receive a negative acknowledgement message corresponding to the first transmission. The operations of 1910 may be performed according to the methods described herein. In some examples, aspects of the operations of 1910 may be performed by a NACK receiver as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1910 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1915, the base station or UE may receive a first indication of a first signal metric for the first transmission and a second indication of a second signal metric for a second transmission of the code block. The operations of 1915 may be performed according to the methods described herein. In some examples, aspects of the operations of 1915 may be performed by a signal metric receiver as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1915 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1920, the base station or UE may determine the difference between the first signal metric for the first transmission and the second signal metric for the second transmission based on the received first and second indications. The operations of 1920 may be performed according to the methods described herein. In some examples, aspects of the operations of 1920 may be performed by a rate matching component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1920 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1925, the base station or UE may determine whether the difference between the first signal metric for the first transmission and the second signal metric for the second transmission satisfies a threshold. The operations of 1925 may be performed according to the methods described herein. In some examples, aspects of the operations of 1925 may be performed by a signal metric component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1925 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1930, the base station or UE may determine a second type of rate matching for the second transmission based on determining whether the threshold is satisfied. The operations of 1930 may be performed according to the methods described herein. In some examples, aspects of the operations of 1930 may be performed by a rate matching component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1930 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 1935, the base station or UE may transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching. The operations of 1935 may be performed according to the methods described herein. In some examples, aspects of the operations of 1935 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 1935 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

FIG. 20 shows a flowchart illustrating a method 2000 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The operations of method 2000 may be implemented by a base station 105, a UE 115, or their components as described herein. For example, the operations of method 2000 may be performed by a communications manager as described with reference to FIGs. 14 through 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2005, the base station or UE may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching. The operations of 2005 may be performed according to the methods described herein. In some examples, aspects of the operations of 2005 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2005 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2010, the base station or UE may receive a negative acknowledgement message corresponding to the first transmission. The operations of 2010 may be performed according to the methods described herein. In some examples, aspects of the operations of 2010 may be performed by a NACK receiver as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2010 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2015, the base station or UE may determine whether a difference between a first code rate of the first transmission and a second code rate of a second transmission of the code block satisfies a threshold. The operations of 2015 may be performed according to the methods described herein. In some examples, aspects of the operations of 2015 may be performed by a code rate component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2015 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2020, the base station or UE may determine a second type of rate matching for the second transmission based on determining whether the threshold is satisfied. The operations of 2020 may be performed according to the methods described herein. In some examples, aspects of the operations of 2020 may be performed by a rate matching component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2020 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2025, the base station or UE may transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching. The operations of 2025 may be performed according to the methods described herein. In some examples, aspects of the operations of 2025 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2025 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

FIG. 21 shows a flowchart illustrating a method 2100 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The operations of method 2100 may be implemented by a base station 105, a UE 115, or their components as described herein. For example, the operations of method 2100 may be performed by a communications manager as described with reference to FIGs. 14 through 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2105, the base station or UE may determine whether a code rate associated with a first transmission of a code block satisfies a threshold. The operations of 2105 may be performed according to the methods described herein. In some examples, aspects of the operations of 2105 may be performed by a code rate component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2105 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2110, the base station or UE may determine a first type of rate matching based on determining whether the threshold is satisfied. The operations of 2110 may be performed according to the methods described herein. In some examples, aspects of the operations of 2110 may be performed by a rate matching component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2110 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2115, the base station or UE may transmit the first transmission, where the first transmission includes a first codeword encoded using a first polar code and rate matched using the first type of rate matching. The operations of 2115 may be performed according to the methods described herein. In some examples, aspects of the operations of 2115 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2115 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2120, the base station or UE may receive a negative acknowledgement message corresponding to the first transmission. The operations of 2120 may be performed according to the methods described herein. In some examples, aspects of the operations of 2120 may be performed by a NACK receiver as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2120 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2125, the base station or UE may determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission. The operations of 2125 may be performed according to the methods described herein. In some examples, aspects of the operations of 2125 may be performed by a rate matching component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2125 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2130, the base station or UE may transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching. The operations of 2130 may be performed according to the methods described herein. In some examples, aspects of the operations of 2130 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2130 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

FIG. 22 shows a flowchart illustrating a method 2200 that supports adaptive rate matching for polar codes in accordance with aspects of the present disclosure. The operations of method 2200 may be implemented by a base station 105, a UE 115, or their components as described herein. For example, the operations of method 2200 may be performed by a communications manager as described with reference to FIGs. 14 through 17. In some examples, a base station may execute a set of instructions to control the functional elements of the base station to perform the functions described below. Additionally or alternatively, a base station may perform aspects of the functions described below using special-purpose hardware.

At 2205, the base station or UE may transmit a first transmission of a code block, where the first transmission includes a first codeword encoded using a first polar code and rate matched using a first type of rate matching. The operations of 2205 may be performed according to the methods described herein. In some examples, aspects of the operations of 2205 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2205 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2210, the base station or UE may receive a negative acknowledgement message corresponding to the first transmission. The operations of 2210 may be performed according to the methods described herein. In some examples, aspects of the operations of 2210 may be performed by a NACK receiver as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2210 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2215, the base station or UE may determine a second type of rate matching for a second transmission of the code block based on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission. The operations of 2215 may be performed according to the methods described herein. In some examples, aspects of the operations of 2215 may be performed by a rate matching component as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2215 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2220, the base station or UE may transmit an indication of the second type of rate matching. The operations of 2220 may be performed according to the methods described herein. In some examples, aspects of the operations of 2220 may be performed by a rate matching indication transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2220 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

At 2225, the base station or UE may transmit the second transmission of the code block, where the second transmission includes a second codeword encoded using a second polar code and rate matched using the second type of rate matching. The operations of 2225 may be performed according to the methods described herein. In some examples, aspects of the operations of 2225 may be performed by a codeword transmitter as described with reference to FIGs. 14 through 17. Additionally or alternatively, means for performing 2225 may, but not necessarily, include, for example, communications manager 1710, network communications manager 1715, transceiver 1720, antenna 1725, memory 1730 (including code 1735) , processor 1740, inter-station communications manager 1745 and/or bus 1750.

It should be noted that the methods described herein describe possible implementations, and that the operations and the steps may be rearranged or otherwise modified and that other implementations are possible. Further, aspects from two or more of the methods may be combined.

Techniques described herein may be used for various wireless communications systems such as code division multiple access (CDMA) , time division multiple access (TDMA) , frequency division multiple access (FDMA) , orthogonal frequency division multiple access (OFDMA) , single carrier frequency division multiple access (SC-FDMA) , and other systems. A CDMA system may implement a radio technology such as CDMA2000, Universal Terrestrial Radio Access (UTRA) , etc. CDMA2000 covers IS-2000, IS-95, and IS-856 standards. IS-2000 Releases may be commonly referred to as CDMA2000 1X, 1X, etc. IS-856 (TIA-856) is commonly referred to as CDMA2000 1xEV-DO, High Rate Packet Data (HRPD) , etc. UTRA includes Wideband CDMA (WCDMA) and other variants of CDMA. A TDMA system may implement a radio technology such as Global System for Mobile Communications (GSM) .

An OFDMA system may implement a radio technology such as Ultra Mobile Broadband (UMB) , Evolved UTRA (E-UTRA) , Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20, Flash-OFDM, etc. UTRA and E-UTRA are part of Universal Mobile Telecommunications System (UMTS) . LTE, LTE-A, and LTE-A Pro are releases of UMTS that use E-UTRA. UTRA, E-UTRA, UMTS, LTE, LTE-A, LTE-A Pro, NR, and GSM are described in documents from the organization named “3rd Generation Partnership Project” (3GPP) . CDMA2000 and UMB are described in documents from an organization named “3rd Generation Partnership Project 2” (3GPP2) . The techniques described herein may be used for the systems and radio technologies mentioned herein as well as other systems and radio technologies. While aspects of an LTE, LTE-A, LTE-A Pro, or NR system may be described for purposes of example, and LTE, LTE-A, LTE-A Pro, or NR terminology may be used in much of the description, the techniques described herein are applicable beyond LTE, LTE-A, LTE-A Pro, or NR applications.

A macro cell generally covers a relatively large geographic area (e.g., several kilometers in radius) and may allow unrestricted access by UEs with service subscriptions with the network provider. A small cell may be associated with a lower-powered base station, as compared with a macro cell, and a small cell may operate in the same or different (e.g., licensed, unlicensed, etc. ) frequency bands as macro cells. Small cells may include pico cells, femto cells, and micro cells according to various examples. A pico cell, for example, may cover a small geographic area and may allow unrestricted access by UEs with service subscriptions with the network provider. A femto cell may also cover a small geographic area (e.g., a home) and may provide restricted access by UEs having an association with the femto cell (e.g., UEs in a closed subscriber group (CSG) , UEs for users in the home, and the like) . An eNB for a macro cell may be referred to as a macro eNB. An eNB for a small cell may be referred to as a small cell eNB, a pico eNB, a femto eNB, or a home eNB. An eNB may support one or multiple (e.g., two, three, four, and the like) cells, and may also support communications using one or multiple component carriers.

The wireless communications systems described herein may support synchronous or asynchronous operation. For synchronous operation, the base stations may have similar frame timing, and transmissions from different base stations may be approximately aligned in time. For asynchronous operation, the base stations may have different frame timing, and transmissions from different base stations may not be aligned in time. The techniques described herein may be used for either synchronous or asynchronous operations.

Information and signals described herein may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

The various illustrative blocks and modules described in connection with the disclosure herein may be implemented or performed with a general-purpose processor, a DSP, an ASIC, an FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration) .

The functions described herein may be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions may be stored on or transmitted over as one or more instructions or code on a computer-readable medium. Other examples and implementations are within the scope of the disclosure and appended claims. For example, due to the nature of software, functions described herein can be implemented using software executed by a processor, hardware, firmware, hardwiring, or combinations of any of these. Features implementing functions may also be physically located at various positions, including being distributed such that portions of functions are implemented at different physical locations.

Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that can be accessed by a general purpose or special purpose computer. By way of example, and not limitation, non-transitory computer-readable media may include random-access memory (RAM) , read-only memory (ROM) , electrically erasable programmable ROM (EEPROM) , flash memory, compact disk (CD) ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, or any other non-transitory medium that can be used to carry or store desired program code means in the form of instructions or data structures and that can be accessed by a general-purpose or special-purpose computer, or a general-purpose or special-purpose processor. Also, any connection is properly termed a computer-readable medium. For example, if the software is transmitted from a website, server, or other remote source using a coaxial cable, fiber optic cable, twisted pair, digital subscriber line (DSL) , or wireless technologies such as infrared, radio, and microwave, then the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwave are included in the definition of medium. Disk and disc, as used herein, include CD, laser disc, optical disc, digital versatile disc (DVD) , floppy disk and Blu-ray disc where disks usually reproduce data magnetically, while discs reproduce data optically with lasers. Combinations of the above are also included within the scope of computer-readable media.

As used herein, including in the claims, “or” as used in a list of items (e.g., a list of items prefaced by a phrase such as “at least one of” or “one or more of” ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase “based on” shall not be construed as a reference to a closed set of conditions. For example, an exemplary step that is described as “based on condition A” may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase “based on” shall be construed in the same manner as the phrase “based at least in part on. ”

In the appended figures, similar components or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If just the first reference label is used in the specification, the description is applicable to any one of the similar components having the same first reference label irrespective of the second reference label, or other subsequent reference label.

The description set forth herein, in connection with the appended drawings, describes example configurations and does not represent all the examples that may be implemented or that are within the scope of the claims. The term “exemplary” used herein means “serving as an example, instance, or illustration, ” and not “preferred” or “advantageous over other examples. ” The detailed description includes specific details for the purpose of providing an understanding of the described techniques. These techniques, however, may be practiced without these specific details. In some instances, well-known structures and devices are shown in block diagram form in order to avoid obscuring the concepts of the described examples.

The description herein is provided to enable a person skilled in the art to make or use the disclosure. Various modifications to the disclosure will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein, but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A method for wireless communication, comprising:

transmitting a first transmission of a code block, wherein the first transmission comprises a first codeword encoded using a first polar code and rate matched using a first type of rate matching;

receiving a negative acknowledgement message corresponding to the first transmission;

determining a second type of rate matching for a second transmission of the code block based at least in part on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission; and

transmitting the second transmission of the code block, wherein the second transmission comprises a second codeword encoded using a second polar code and rate matched using the second type of rate matching.
The method of claim 1, wherein determining the second type of rate matching for the second transmission based at least in part on the difference in the signal metrics comprises:

determining whether a difference between a first signal metric for the first transmission and a second signal metric for the second transmission satisfies a threshold; and

determining the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The method of claim 2, further comprising:

receiving a first indication of the first signal metric for the first transmission and a second indication of the second signal metric for the second transmission; and

determining the difference between the first signal metric for the first transmission and the second signal metric for the second transmission based at least in part on the received first and second indications.
The method of claim 3, wherein:

receiving each of the first and second indications comprises receiving channel state information (CSI) , a sounding reference signal (SRS) , or a combination thereof.
The method of claim 2, wherein the first signal metric for the first transmission and the second signal metric for the second transmission correspond to signal-to-noise ratios for a channel associated with the first and second transmissions.
The method of claim 1, wherein determining the second type of rate matching for the second transmission based at least in part on the difference in the code rates comprises:

determining whether a difference between a first code rate of the first transmission and a second code rate of the second transmission satisfies a threshold; and

determining the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The method of claim 1, further comprising:

encoding a first set of information bits according to the first polar code to generate a first set of polar-encoded bits; and

encoding a second set of information bits according to the second polar code to generate a second set of polar-encoded bits, wherein the second set of information bits comprises the first set of information bits.
The method of claim 7, wherein at least two information bits of the second set of information bits corresponds to one information bit of the first set of information bits.
The method of claim 7, wherein the second set of polar-encoded bits comprises the first set of polar-encoded bits.
The method of claim 1, further comprising:

determining whether a code rate associated with the first transmission satisfies a threshold; and

determining the first type of rate matching based at least in part on determining whether the threshold is satisfied.
The method of claim 1, further comprising:

transmitting an indication of the second type of rate matching.
The method of claim 11, wherein the indication is transmitted via downlink control information scheduling the second transmission.
The method of claim 1, wherein:

determining the second type of rate matching for the second transmission is further based at least in part on the first type of rate matching.
The method of claim 13, wherein the first type of rate matching is puncturing, and wherein the second type of rate matching is one of block puncturing, 2 block puncturing, block shortening, or 2 block shortening based at least in part on the first type of rate matching being puncturing.
The method of claim 13, wherein the first type of rate matching is shortening, and wherein the second type of rate matching is one of block shortening, 2 block shortening, block puncturing, or 2 block puncturing based at least in part on the first type of rate matching being shortening.
An apparatus for wireless communication, comprising:

a processor,

memory in electronic communication with the processor; and

instructions stored in the memory and executable by the processor to cause the apparatus to:

transmit a first transmission of a code block, wherein the first transmission comprises a first codeword encoded using a first polar code and rate matched using a first type of rate matching;

receive a negative acknowledgement message corresponding to the first transmission;

determine a second type of rate matching for a second transmission of the code block based at least in part on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission; and

transmit the second transmission of the code block, wherein the second transmission comprises a second codeword encoded using a second polar code and rate matched using the second type of rate matching.
The apparatus of claim 16, wherein the instructions to determine the second type of rate matching for the second transmission based at least in part on the difference in the signal metrics are executable by the processor to cause the apparatus to:

determine whether a difference between a first signal metric for the first transmission and a second signal metric for the second transmission satisfies a threshold; and

determine the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The apparatus of claim 17, wherein the instructions are further executable by the processor to cause the apparatus to:

receive a first indication of the first signal metric for the first transmission and a second indication of the second signal metric for the second transmission; and

determine the difference between the first signal metric for the first transmission and the second signal metric for the second transmission based at least in part on the received first and second indications.
The apparatus of claim 18, wherein the instructions to receive each of the first and second indications are executable by the processor to cause the apparatus to receive channel state information (CSI) , a sounding reference signal (SRS) , or a combination thereof.
The apparatus of claim 17, wherein the first signal metric for the first transmission and the second signal metric for the second transmission correspond to signal-to-noise ratios for a channel associated with the first and second transmissions.
The apparatus of claim 16, wherein the instructions to determine the second type of rate matching for the second transmission based at least in part on the difference in the code rates are executable by the processor to cause the apparatus to:

determine whether a difference between a first code rate of the first transmission and a second code rate of the second transmission satisfies a threshold; and

determine the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The apparatus of claim 16, wherein the instructions are further executable by the processor to cause the apparatus to:

encode a first set of information bits according to the first polar code to generate a first set of polar-encoded bits; and

encode a second set of information bits according to the second polar code to generate a second set of polar-encoded bits, wherein the second set of information bits comprises the first set of information bits.
The apparatus of claim 22, wherein at least two information bits of the second set of information bits corresponds to one information bit of the first set of information bits.
The apparatus of claim 22, wherein the second set of polar-encoded bits comprises the first set of polar-encoded bits.
The apparatus of claim 16, wherein the instructions are further executable by the processor to cause the apparatus to:

determine whether a code rate associated with the first transmission satisfies a threshold; and

determine the first type of rate matching based at least in part on determining whether the threshold is satisfied.
The apparatus of claim 16, wherein the instructions are further executable by the processor to cause the apparatus to:

transmit an indication of the second type of rate matching.
The apparatus of claim 26, wherein the indication is transmitted via downlink control information scheduling the second transmission.
The apparatus of claim 16, wherein determining the second type of rate matching for the second transmission is further based at least in part on the first type of rate matching.
The apparatus of claim 28, wherein the first type of rate matching is puncturing, and wherein the second type of rate matching is one of block puncturing, 2 block puncturing, block shortening, or 2 block shortening based at least in part on the first type of rate matching being puncturing.
The apparatus of claim 28, wherein the first type of rate matching is shortening, and wherein the second type of rate matching is one of block shortening, 2 block shortening, block puncturing, or 2 block puncturing based at least in part on the first type of rate matching being shortening.
An apparatus for wireless communication, comprising:

means for transmitting a first transmission of a code block, wherein the first transmission comprises a first codeword encoded using a first polar code and rate matched using a first type of rate matching;

means for receiving a negative acknowledgement message corresponding to the first transmission;

means for determining a second type of rate matching for a second transmission of the code block based at least in part on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission; and

means for transmitting the second transmission of the code block, wherein the second transmission comprises a second codeword encoded using a second polar code and rate matched using the second type of rate matching.
The apparatus of claim 31, wherein the means for determining the second type of rate matching for the second transmission based at least in part on the difference in the signal metrics comprises:

means for determining whether a difference between a first signal metric for the first transmission and a second signal metric for the second transmission satisfies a threshold; and

means for determining the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The apparatus of claim 32, further comprising:

means for receiving a first indication of the first signal metric for the first transmission and a second indication of the second signal metric for the second transmission; and

means for determining the difference between the first signal metric for the first transmission and the second signal metric for the second transmission based at least in part on the received first and second indications.
The apparatus of claim 33, wherein the means for receiving each of the first and second indications comprises means for receiving channel state information (CSI) , a sounding reference signal (SRS) , or a combination thereof.
The apparatus of claim 32, wherein the first signal metric for the first transmission and the second signal metric for the second transmission correspond to signal-to-noise ratios for a channel associated with the first and second transmissions.
The apparatus of claim 31, wherein the means for determining the second type of rate matching for the second transmission based at least in part on the difference in the code rates comprises:

means for determining whether a difference between a first code rate of the first transmission and a second code rate of the second transmission satisfies a threshold; and

means for determining the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The apparatus of claim 31, further comprising:

means for encoding a first set of information bits according to the first polar code to generate a first set of polar-encoded bits; and

means for encoding a second set of information bits according to the second polar code to generate a second set of polar-encoded bits, wherein the second set of information bits comprises the first set of information bits.
The apparatus of claim 37, wherein at least two information bits of the second set of information bits corresponds to one information bit of the first set of information bits.
The apparatus of claim 37, wherein the second set of polar-encoded bits comprises the first set of polar-encoded bits.
The apparatus of claim 31, further comprising:

means for determining whether a code rate associated with the first transmission satisfies a threshold; and

means for determining the first type of rate matching based at least in part on determining whether the threshold is satisfied.
The apparatus of claim 31, further comprising:

means for transmitting an indication of the second type of rate matching.
The apparatus of claim 41, wherein the indication is transmitted via downlink control information scheduling the second transmission.
The apparatus of claim 31, wherein determining the second type of rate matching for the second transmission is further based at least in part on the first type of rate matching.
The apparatus of claim 43, wherein the first type of rate matching is puncturing, and wherein the second type of rate matching is one of block puncturing, 2 block puncturing, block shortening, or 2 block shortening based at least in part on the first type of rate matching being puncturing.
The apparatus of claim 43, wherein the first type of rate matching is shortening, and wherein the second type of rate matching is one of block shortening, 2 block shortening, block puncturing, or 2 block puncturing based at least in part on the first type of rate matching being shortening.
A non-transitory computer-readable medium storing code for wireless communication, the code comprising instructions executable by a processor to:

transmit a first transmission of a code block, wherein the first transmission comprises a first codeword encoded using a first polar code and rate matched using a first type of rate matching;

receive a negative acknowledgement message corresponding to the first transmission;

determine a second type of rate matching for a second transmission of the code block based at least in part on at least one of a difference in signal metrics or code rates between the first transmission and the second transmission; and

transmit the second transmission of the code block, wherein the second transmission comprises a second codeword encoded using a second polar code and rate matched using the second type of rate matching.
The non-transitory computer-readable medium of claim 46, wherein the instructions to determine the second type of rate matching for the second transmission based at least in part on the difference in the signal metrics are executable to:

determine whether a difference between a first signal metric for the first transmission and a second signal metric for the second transmission satisfies a threshold; and

determine the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The non-transitory computer-readable medium of claim 47, wherein the instructions are further executable to:

receive a first indication of the first signal metric for the first transmission and a second indication of the second signal metric for the second transmission; and

determine the difference between the first signal metric for the first transmission and the second signal metric for the second transmission based at least in part on the received first and second indications.
The non-transitory computer-readable medium of claim 48, wherein the instructions to receive each of the first and second indications are executable by the processor to cause the apparatus to receive channel state information (CSI) , a sounding reference signal (SRS) , or a combination thereof.
The non-transitory computer-readable medium of claim 47, wherein the first signal metric for the first transmission and the second signal metric for the second transmission correspond to signal-to-noise ratios for a channel associated with the first and second transmissions.
The non-transitory computer-readable medium of claim 46, wherein the instructions to determine the second type of rate matching for the second transmission based at least in part on the difference in the code rates are executable to:

determine whether a difference between a first code rate of the first transmission and a second code rate of the second transmission satisfies a threshold; and

determine the second type of rate matching for the second transmission based at least in part on determining whether the threshold is satisfied.
The non-transitory computer-readable medium of claim 46, wherein the instructions are further executable to:

encode a first set of information bits according to the first polar code to generate a first set of polar-encoded bits; and

encode a second set of information bits according to the second polar code to generate a second set of polar-encoded bits, wherein the second set of information bits comprises the first set of information bits.
The non-transitory computer-readable medium of claim 52, wherein at least two information bits of the second set of information bits corresponds to one information bit of the first set of information bits.
The non-transitory computer-readable medium of claim 52, wherein the second set of polar-encoded bits comprises the first set of polar-encoded bits.
The non-transitory computer-readable medium of claim 46, wherein the instructions are further executable to:

determine whether a code rate associated with the first transmission satisfies a threshold; and

determine the first type of rate matching based at least in part on determining whether the threshold is satisfied.
The non-transitory computer-readable medium of claim 46, wherein the instructions are further executable to:

transmit an indication of the second type of rate matching.
The non-transitory computer-readable medium of claim 56, wherein the indication is transmitted via downlink control information scheduling the second transmission.
The non-transitory computer-readable medium of claim 46, wherein determining the second type of rate matching for the second transmission is further based at least in part on the first type of rate matching.
The non-transitory computer-readable medium of claim 58, wherein the first type of rate matching is puncturing, and wherein the second type of rate matching is one of block puncturing, 2 block puncturing, block shortening, or 2 block shortening based at least in part on the first type of rate matching being puncturing.
The non-transitory computer-readable medium of claim 58, wherein the first type of rate matching is shortening, and wherein the second type of rate matching is one of block shortening, 2 block shortening, block puncturing, or 2 block puncturing based at least in part on the first type of rate matching being shortening.