Abstract: Aspects of the disclosure relate to rate-matching a stream of bits encoded using polar codes. An exemplary method generally includes determining a mother code size (N) for transmitting an encoded stream of bits based, at least in part, on a minimum supported code rate for transmitting the encoded stream of bits (Rmin), a control information size of the encoded stream of bits (K), a number of coded bits for transmission (E), and a maximum mother code size (Nmax), encoding a stream of bits using a polar code of size (N, K) and storing the encoded stream of bits in a circular buffer, and performing rate-matching on the stored encoded stream of bits based, at least in part, on a comparison among the mother code size (N), the control information size of the encoded stream of bits (K), and the number of coded bits for transmission (E).

Abstract: Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to methods and apparatus for rate-matching control channels using polar codes. An exemplary method generally includes encoding a stream of bits using a polar code, determining a size of a circular buffer for storing the encoded stream of bits based, at least in part, on a minimum supported code rate and a control information size, and performing rate-matching on stored encoded stream of bits based, at least in part, on a mother code size, N, and a number of coded bits for transmission, E.

Abstract: Aspects of the disclosure relate to rate-matching a stream of bits encoded using polar codes. An exemplary method generally includes determining a mother code size (N) for transmitting an encoded stream of bits based, at least in part, on a minimum supported code rate for transmitting the encoded stream of bits (Rmin), a control information size of the encoded stream of bits (K), a number of coded bits for transmission (E), and a maximum mother code size (Nmax), encoding a stream of bits using a polar code of size (N, K) and storing the encoded stream of bits in a circular buffer, and performing rate-matching on the stored encoded stream of bits based, at least in part, on a comparison among the mother code size (N), the control information size of the encoded stream of bits (K), and the number of coded bits for transmission (E).

Abstract: Aspects of the disclosure relate to wireless communication devices configured to encode information blocks to produce code blocks and interleave the code blocks utilizing an interleaver including a plurality of rows and a plurality of columns. In some examples, the interleaver includes a right isosceles triangle-shaped matrix of rows and columns. In other examples, the interleaver includes a rectangle-shaped matrix of rows and columns.

Abstract: Aspects of the disclosure relate to wireless communication devices configured to generate polar codewords utilizing a single master sequence constructed using density evolution with a nested structure for identifying the frozen bit locations and information bit locations. This single master sequence may be used for any codeword length N up to a maximum codeword length Nmax, and may further be utilized for any code rate R. For example, from the master sequence of length Nmax, a bit location sequence S with codeword length N (where N<Nmax) may be obtained by selecting the bit locations (indexes) in the master sequence corresponding to each bit location in S in the order provided in the master sequence.

Abstract: Various aspects of the disclosure relate to rate matching techniques for block encoding. In some aspects, a decision regarding whether to use repetition-based rate matching or puncture-based rate matching is made based on a block size of information being encoded. In some aspects, repetition-based rate matching uses a bit-reversal permutation technique.

Abstract: For communication utilizing polar codes, a hybrid automatic repeat request (HARQ) algorithm is provided that takes advantage of the benefits of chase combining HARQ (HARQ-CC) and incremental redundancy HARQ (HARQ-IR), by selecting one or the other in accordance with a code rate of the first transmission. In some examples, the HARQ algorithm utilizes HARQ-IR when the code rate in the first transmission is greater than a code rate threshold, and utilizes HARQ-CC when the code rate in the first transmission is less than the code rate threshold.

Abstract: Design of precoding and feedback for user equipment (UE)-specific reference signals (UE-RS)-based open-loop and semi-open-loop multiple input, multiple output (MIMO) systems is discussed. Aspects of the present disclosure provide for sub-resource block (RB) random precoding that allows for greater diversity gain in a lower bandwidth. In addition, the recoding may be performed using resource element (RE)-level layer shifting that provides for a number of precoders to be assigned to a number of layers for every such continuous subcarrier. As such, two codewords may experience the same effective channel quality with channel quality indicators (CQI) being averaged across all of the layers.

Abstract: Methods, systems, and devices are described for discontinuous transmission and/or discontinuous reception in time division duplex (TDD) systems that may have data transmission formats dynamically reconfigured. An initial uplink-downlink (UL-DL) configuration for TDD communication between an eNB and user equipment (UE) may be established. This initial UL-DL configuration may be reconfigured to a different UL-DL configuration for one or more UEs in communication with the eNB. When a UE switches to discontinuous reception (DRX) mode, it may monitor control information from the eNB during DRX on periods, a frequency of the DRX on periods based on a reference UL-DL configuration irrespective of any reconfiguration of UL-DL configuration for a particular UE. In some aspects, a UE that is operating in a UL-DL reconfiguration mode may, upon entering DRX mode, autonomously discontinue operating in the UL-DL reconfiguration mode.

Abstract: Polar codes may be generated with a variable block length utilizing puncturing. Some puncturing schemes consider punctured bits as unknown bits, and set the log likelihood ratio (LLR) for those bits to zero; while other puncturing schemes consider punctured bits as known bits, and set the LLR for those bits to infinity. Each of these puncturing schemes has been observed to provide benefits over the other under different circumstances, especially corresponding to different coding rates or different signal to noise ratio (SNR). According to aspects of the present disclosure, both puncturing schemes are compared, and the puncturing scheme resulting in the better performance is utilized for transmission.

Abstract: Certain aspects of the present disclosure provide methods and apparatus for linear precoding in full-dimensional MIMO (FD-MIMO) systems. According to aspects, an eNB may compress a larger number of antenna elements to a smaller number of antenna ports. The eNB may use a port precoding matrix to transmit reference signals to a UE, receive feedback regarding CSI based on the reference signals, and transmit data to the UE, based on a mapping of multiple data layers and mapping of antenna ports to the physical antenna elements. Further, aspects include performing elevation beamforming by dynamically forming one or more vertical sectors based on UE feedback in the elevation domain.

Abstract: Methods and apparatuses for wireless communications are described. In an aspect, a method and apparatus may include determining that a second transmission is decoded incorrectly in response to a first received indication on a communication channel. The method and apparatus may further include transmitting, on the communication channel, a third transmission and a fourth transmission based on a determination that the second transmission is decoded incorrectly, wherein the third transmission corresponds to a coded bit set of the third transmission including a first group of information bits of a coded bit set of a first transmission and a second group of information bits of a coded bit set of the second transmission and the fourth transmission corresponds to a coded bit set of the fourth transmission including a combination of the coded bit sets of the first transmission, the second transmission, and the third transmission.

Abstract: Various aspects of the disclosure relate to mapping different information to different sub-channels. For example, information for different users may be mapped to different Polar code sub-channels. In some aspects, the mapping may be unbalanced in that different information is mapped to different sub-channels according to the quality (e.g., in terms of error probability) of the sub-channels and a criterion associated with the information. For example, control information for users that are experiencing the worst channel quality (e.g., in a wireless communication channel) may be mapped to the Polar code sub-channels that have the best quality.

Abstract: Various aspects of the disclosure relate to rate matching techniques for block encoding. In some aspects, a decision regarding whether to use repetition-based rate matching or puncture-based rate matching is made based on a block size of information being encoded. In some aspects, repetition-based rate matching uses a bit-reversal permutation technique.

Abstract: Methods and apparatus for constructing polar codes are provided. A transmitter determines at least one set of parameters corresponding to data to be transmitted, and a set of sorting indices corresponding to bits of the data to be transmitted based on the set of parameters, the set of sorting indices indicating a position set of the bits to be transmitted. The transmitter polar encodes the data based at least on the set of parameters and the set of sorting indices to generate a coded block of the data, and transmits the coded block of the data.

Abstract: A hybrid class B channel state information (CSI) reference signal (CSI-RS) scheme is discussed which configures one cell-common beamformed CSI-RS resource for beam tracking and another UE-specific beamformed CSI-RS resource for CSI feedback. The cell-common beamformed CSI-RS resource may be transmitted at a longer periodicity and shared by user equipments (UEs) in the cell. The beamforming may be cycled over a set of predefined weights transparent to UE. The UE-specific beamformed CSI-RS may be transmitted at a shorter periodicity and can be activated dynamically to allow resource sharing among multiple UEs. The UEs will report a CSI for the cell-common beamformed CSI-RS resource which provides a quality indicator for the associated cell-common beam and is utilized by the base station to determine the precoding weight for the UE-specific beamformed CSI-RS resource. Both resources can be configured with different parameter sets, such as number of ports, codebook type, and CSI reporting parameters.

Abstract: Certain aspects of the present disclosure relate to methods and apparatus for flexible resource mapping and modulation and coding scheme (MCS) determination in wireless communication systems. According to certain aspects, a method for wireless communications that may be performed by a transmitter is provided. The method generally includes determining MCSs to use for each of multiple portions of a transport block and transmitting the portions of the transport block according to the determined MCSs to a wireless node. Flexible MCS and resource mapping determination may improve demodulation performance for code blocks that are far from pilots.

Abstract: Certain aspects of the present disclosure generally relate to wireless communications and, more particularly, to methods and apparatus for dynamic frozen polar codes, for example, for control channels. An exemplary method may be performed at the encoder. The method generally includes encoding a stream of bits using a polar code. The encoding includes selecting a first set of channel indices for encoding information bits. The encoding includes selecting a second set of the channel indices smaller than a channel index for a first information bit for encoding fixed frozen bits. The encoding includes selecting remaining channel indices for dynamic frozen (PCF) bits having values based on one or more of the information bits. The method includes transmitting the encoded stream of bits.

Abstract: Methods, systems, and devices for wireless communication are described. In order to exchange data over a given wireless communication network, a wireless device may first perform a cell acquisition procedure (e.g., to determine cell-specific information such as timing and frequency offsets, bandwidth, control channel formatting, etc.). In some systems, aspects of the timing information may be conveyed with scrambling codes applied to a master information block (MIB). Physical broadcast channel (PBCH) payloads, including MIB transmissions, may be jointly encoded with synchronization signal indices. Bursts of MIB transmissions may thus be decoded without blind decoding while maintaining error protection and low latency that may be necessary to obtain critical system information within the MIB.

Abstract: Methods, systems, and apparatuses are described for flexible transmissions on one or more frequency division duplexing resources. In some aspects, a subset of resources originally allocated for transmissions in a frequency division duplex (FDD) mode of operation associated with a first base station is identified for reallocation, and the identified subset of resources is reallocated to transmissions in a time division duplex (TDD) mode of operation, for example, associated with a second base station.