Abstract: Techniques are provided for retransmission of Physical Uplink Shared Channel (PUCCH) for Ultra Reliable Low Latency Communications (URLLC). A User Equipment (UE) transmits at least one code block of a control channel, the at least one code block including Channel State Information (CSI), wherein each code block is polar encoded by assigning bit indices of the code block to bit channels in a particular order of reliabilities of the bit channels. The UE detects a trigger, and in response, retransmits at least a portion of each code block including retransmitted CSI, wherein the portion is polar encoded by assigning bit indices of the retransmitted CSI to the bit channels in the reverse order of reliabilities of the bit channels as compared to the polar encoding of the CSI.

Abstract: Various aspects of the present disclosure generally relate to wireless communication. In some aspects, a wireless communication device may perform a first transmission of a communication that is encoded using a polar coding technique; and perform at least one retransmission of the communication, wherein more resources are allocated for the at least one retransmission than for the first transmission, and wherein the at least one retransmission includes an incremental redundancy version of the communication and a version of the communication for Chase combination. Numerous other aspects are provided.

Abstract: Certain aspects of the present disclosure generally relate to techniques for encoding and decoding bits of information using cyclic redundancy check (CRC) concatenated polar encoding and decoding. The CRC concatenated polar encoding techniques may avoid transmission of dummy bits. A method generally includes obtaining the bits of information to be transmitted. The method includes performing CRC outer encoding of the bits of information using an even-weighted generator polynomial to produce CRC encoded bits. The method includes performing polar inner encoding of the CRC encoded bits to generate a codeword. The method includes discarding a first code bit at a beginning of the codeword. The shortened codeword is transmitted over a wireless medium. In another method, bit-level scrambling is performed on the CRC encoded bits before the polar encoding to avoid generating a dummy bit. In another method, only odd-weighted generator polynomials are selected to avoid generating the dummy bit.

Abstract: Certain aspects of the present disclosure relate to methods and apparatus relating to rate matching for new radio (NR) physical downlink shared channel (PDSCH) and physical uplink shared channel (PUSCH). In certain aspects, a method includes receiving a rate matching resource (RMR) configuration from a serving cell. The method also includes identifying one or more first resource elements (REs) to be rate matched around at least in part based on a transmission numerology associated with the RMR configuration, wherein the one or more first REs are used for reference signal (RS) transmission in the serving cell or a neighboring cell. The method further includes mapping a physical downlink shared channel (PDSCH) to one or more second REs not including the first REs.

Abstract: Certain aspects of the present disclosure relate to methods and apparatus relating to UCI layer mapping. According to certain aspects, a mapping rule maps UCI to one or more layers of a physical uplink shared channel (PUSCH) transmission based on at least one of a rank of the PUSCH transmission or a modulation and coding scheme (MCS) of the PUSCH transmission.

Abstract: Certain aspects of the present disclosure provide techniques and apparatus for signaling precoder(s) for non-PMI based CSI feedback.

Abstract: Methods, systems, and devices for wireless communications are described. In some wireless communications systems, a base station may implement polar coding to generate codewords for transmission, for example, in a physical broadcast channel (PBCH). The base station may identify a subset of the bandwidth allocated for PBCH transmission (e.g., corresponding to a bandwidth for a synchronization signal), and may assign sub-channels to information bits based on the identified bandwidth subset. The base station may generate a codeword based on the assigned sub-channels, and may map a subset of encoded bits for the codeword to the subset of the bandwidth such that the subset of encoded bits includes bits corresponding to the assigned subchannels for the information bits. A user equipment (UE) may receive the encoded bits in the subset of the bandwidth, and may decode the subset of encoded bits to determine the information bits.

Abstract: Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to methods and apparatus for rate-matching a stream of bits encoded using polar codes. An exemplary method generally includes encoding K information bits using a polar code with a mother code length, N, to generate a stream of encoded bits storing a portion of the encoded bits in a circular buffer of size N reordering P blocks of the circular buffer according to row weights of a Hadamard matrix J interlacing the encoded bits of the blocks having a same row weight selecting, based on the row weights, a subset of the encoded bits in the blocks to modify modifying the selected subset of the encoded bits and transmitting the encoded bits in the P blocks, subsequent to modifying the selected subset of the encoded bits, via transmission resources.

Abstract: Certain aspects of the present disclosure generally relate to methods and apparatus for generating and encoding bits of CSI report. In some cases, a UE may determine a payload size for channel state information (CSI) reporting based, at least in part, on a supported rank, calculate a packet length for the CSI reporting based on the determined payload size, and encode the CSI for a selected CSI resource index (CRI), based on the payload size and the calculated packet length, to generate a coded packet.

Abstract: Certain aspects of the present disclosure generally relate to methods and apparatus for generating and reporting CSI.

Abstract: Methods, systems, and devices for wireless communication are described. In wireless systems supporting multiple-input, multiple-output (MIMO) transmissions, devices may implement beam-forming to improve reliability of communications. A user equipment (UE) may select a set of beams, and corresponding beam indices, for communication based on reference signals received from a base station. The UE may determine values corresponding to each of the beam indices using a scalable set of tables. For example, the UE may select a subset of the tables based on the number of selected beams, and may determine the values based on these tables. In this way, the UE may efficiently store sets of tables for multiple different configurations. The UE may sum the corresponding values to obtain a combination index value, and may transmit the combination index value to the base station. The base station may determine the selected beams based on this combination index value.

Abstract: Methods, systems, and devices for wireless communication are described for polar coding with rate matching. A transmitter may construct input channels into a polar encoder to provide an information bit vector that does not include punctured or shortened bits. One or more transmission capacity factors may be used in identifying the information bit vector, which may be mapped to one or more of a codeword length of the polar code or a number of transmitted bits in each codeword. A number of different rate matching schemes may be available for transmissions, and may be selected based on one or more polar coding parameters. In some cases, mapping techniques may be used in two or more different rate matching schemes.

Abstract: The described techniques provide for the use of sub-band-specific reference signal precoding. A user equipment (UE) may apply multiple precoding matrices to a reference signal to generate a set of precoded reference signals and may transmit the precoded reference signals over respective sub-bands within a given reference signal resource set. In some cases, the UE may transmit a different set of precoded reference signals in each of multiple reference signal resource sets. Upon receiving the precoded reference signals, a base station may perform wideband channel estimation for each sub-band in the given reference signal resource set. The base station may compute an average spectral efficiency for each reference signal resource set and may transmit a report to the UE. The report may include one or more communication parameters for future communications between the UE and base station.

Abstract: Methods, systems, and devices are described for wireless communications that support transmitting channel state information (CSI) feedback utilizing flexible uplink control resources. A method may include determining a size of a frequency subband corresponding to components of a CSI feedback report based on configuration signaling or a size of allocated uplink control resources. A method may include encoding a CSI report into a single packet and transmitting the single packet over uplink control resources. A method may include encoding a first plurality of components of a CSI report in a first packet, encoding a second plurality of components of the CSI report in a second packet, and mapping the packets to uplink control resources. A method may include transmitting a first plurality of components of a CSI report on a first slot and a second plurality of components of the CSI report on one or more subsequent slots.

Abstract: A user equipment (UE) may be configured with a first set of indexed timing offsets for determining offsets between uplink grants and uplink data transmissions and a second set of indexed timing offsets for determining offsets between an aperiodic channel state information (CSI) trigger and transmission of an aperiodic CSI report. A UE may receive both an uplink grant for an uplink data transmission and an aperiodic CSI report trigger. The UE may determine a timing offset for transmission of both the uplink data transmission and the aperiodic CSI report. The timing offset may be based at least in part on the first set of indexed timing offsets, the second set of indexed timing offsets, or a third set of indexed timing offsets for joint transmission of uplink data and aperiodic CSI. The UE may transmit the uplink data transmission and the aperiodic CSI report according to the timing offset.

Abstract: Reporting aperiodic channel state information (A-CSI) via a physical uplink control channel (PUCCH) is disclosed. A UE receives a configuration to report aperiodic channel state information (A-CSI) using physical uplink control channel (PUCCH). The UE can report lightweight A-CSI via short/long PUCCH or may report heavy A-CSI via short/long PUCCH. The UE receives a trigger signal for PUCCH-based A-CSI reporting either by a dedicated downlink grant or by a group common DCI. When triggered via a DCI-based trigger, the PUCCH resource can be either a resource used for HARQ-ACK feedback, e.g., short PUCCH; or a semi-static configured PUCCH resource, e.g., either short PUCCH or long PUCCH. When triggered via a group common DCI-based trigger, the PUCCH resource can be either semi-statically configured, or dynamically indicated.

Abstract: Methods, systems, and devices for wireless communication are described. Generally, the described techniques provide for communicating an uplink grant and a channel state information reference signal (CSI-RS) trigger. A wireless device may identify e a pending collision for a slot of a carrier between a CSI-RS and uplink data. The wireless device may determine a communication configuration for the CSI-RS and the uplink data such that no collision occurs. The determined communication configuration for the CSI-RS may include delaying one of the colliding signals, transmitting only one of the colliding signals and suppressing the other, or reconfiguring the slot such that both signals can be transmitted successfully. Additionally, the UE and the base station may determine a CSI reporting configuration based on the determined communication configuration.

Abstract: Methods, systems, and devices for wireless communication are described. A transmitter may generate a first segmentation based on a first subset of control information and a second segmentation based on jointly encoding the first subset and a second subset of the control information. The transmitter may polar encode the first segmentation to generate a first codeword and the second segmentation to generate a second codeword, and transmit the first and second codewords. A receiver may determine a first bit sequence corresponding to the first subset based on decoding a first codeword and determine an error detection code (EDC) and a second bit sequence corresponding to the second subset based on decoding a second codeword. The receiver may perform error detection on the first and second bit sequences based on the determined EDC, and output the first bit sequence and the second bit sequence or a decoding error.

Abstract: Methods and apparatus for implementing enhancements to advanced Channel State Information (CSI) reporting procedures are provided. A User Equipment (UE) receives at least one trigger message for reporting advanced CSI by the UE, and takes one or more actions to reduce at least one of feedback overhead or processing at the UE associated with the reporting.

Abstract: A signaling design for multiple aperiodic channel state information (M-A-CSI) feedback is disclosed. In new radio (NR) networks, there may be scenarios where M-A-CSI are triggered and reported simultaneously. Timing issues may arise because of the different delay periods for difference CSI processes and reporting. In a first aspect, a general set of delay times for the M-A-CSI maybe signaled to the user equipment (UE) from which a candidate set is selected by the UE based on various CSI related settings. An indication from the base station may then be used to select the delay from the candidate set. In a second aspect, a delay period may be selected from the set of delays associated with and corresponding to the M-A-CSI.