Abstract:
Certain aspects of the present disclosure generally relate to techniques for puncturing of structured low-density parity-check (LDPC) codes. Certain aspects of the present disclosure generally relate to methods and apparatus for a high-performance, flexible, and compact LDPC code. Certain aspects can enable LDPC code designs to support large ranges of rates, blocklengths, and granularity, while being capable of fine incremental redundancy hybrid automatic repeat request (IR-HARD) extension while maintaining good floor performance, a high-level of parallelism to deliver high throughout performance, and a low description complexity.
Abstract:
This disclosure provides systems, methods and apparatus, including computer programs encoded on computer storage media, for encoding data for wireless transmissions. In one aspect, a wireless device may encode a number (M) of systematic bits for transmission to a receiving device. The systematic bits may be encoded using a low-density parity-check (LDPC) code to produce an LDPC codeword. The LDPC codeword may include a number (N) of codeword bits, including the M systematic bits and one or more parity bits. The wireless device may further puncture a number (K) of the codeword bits to produce a punctured codeword having a code rate M/(N−K)>5/6. The wireless device may transmit the N−K remaining codeword bits, over a wireless channel, to a receiving device.
Abstract:
This disclosure provides methods, devices and systems for encoding data in wireless communications. Some implementations more specifically relate to performing a first encoding operation on data bits of a code block to shape the amplitudes of the resultant symbols such that the amplitudes have a non-uniform distribution. In some aspects, the probabilities associated with the respective amplitudes generally increase with decreasing amplitude. For example, the non-uniform distribution of the amplitudes of the symbols may be approximately Gaussian. In some aspects, the first encoding operation is or includes a prefix encoding operation having an effective coding rate greater than 0.94 but less than 1. The first encoding operation is followed by a second encoding operation that also adds redundancy but does not alter the data bits themselves. In some aspects, the second encoding operation is or includes a low-density parity-check (LDPC) encoding operation associated with a coding rate greater than 5/6.
Abstract:
Techniques and apparatus are provided for efficiently generating multiple lifted low-density parity-check (LDPC) codes for a range of block lengths and having good performance. A method for wireless communications by a transmitting device generally includes selecting integer lifting values for a first lifting size value Z, selected from a range of lifting size values, wherein the selected integer lifting value is greater than a maximum lifting size value of the range of lifting size values; determining one or more integer lifting values for generating at least a second lifted LDPC code having a second lifting size value based on an operation involving the second lifting size value and the selected one or more integer lifting values for generating the first lifted LDPC code; encoding a set of information bits based on the second lifted LDPC to produce a code word; and transmitting the code word.
Abstract:
Certain aspects of the present disclosure generally relate to techniques for puncturing of structured low-density parity-check (LDPC) codes. Certain aspects of the present disclosure generally relate to methods and apparatus for a high-performance, flexible, and compact LDPC code. Certain aspects can enable LDPC code designs to support large ranges of rates, blocklengths, and granularity, while being capable of fine incremental redundancy hybrid automatic repeat request (IR-HARQ) extension while maintaining good floor performance, a high-level of parallelism to deliver high throughout performance, and a low description complexity.
Abstract:
Certain aspects of the present disclosure generally relate to techniques for compactly describing lifted low-density parity-check (LDPC) codes. A method for wireless communications by a transmitting device is provided. The method generally includes selecting a first lifting size value Z and a first set of lifting values for generating a first lifted LDPC code; generating the first lifted LDPC code by applying the first set of lifting values to interconnect edges in Z copies of a base parity check matrix (PCM) having a first number of base variable nodes and a second number of base check nodes to obtain a first lifted PCM corresponding to the first lifted LDPC code; determining a second set of lifting values for generating second lifted PCM corresponding to a second lifted LDPC code for a second lifting size value based on the first lifted PCM and the first set of lifting values; encoding a set of information bits based on at least one of: the first lifted LDPC code or the second lifted LDPC code to produce a code word; and transmitting the code word.
Abstract:
Methods, systems, and devices for wireless communication are described. In some examples, a wireless device (e.g., a user equipment (UE) or a base station) may encode a codeword from a set of information bits using an LDPC code. The wireless device may then transmit multiple versions of the codeword to improve the chances of the codeword being received. In some aspects, the wireless device may use the techniques herein to generate self-decodable redundancy versions of the codeword to be transmitted to the receiving device. Accordingly, a receiving device may be able to identify information bits from one or more redundancy versions of the codeword even if the receiving device failed to receive an original transmission of the codeword.
Abstract:
Methods and apparatus for controlling access to secure areas are described. Time varying values are generated from access device identifiers, e.g., door identifiers. The time varying value, e.g., a hashed door identifier value, is transmitted as a VLC signal by a luminaire near the door to which the hashed identifier corresponds. A mobile detects the transmitted hashed door identifier value and sends an access request via a wireless signal, e.g., a radio signal. The access request includes a value generated from the received hashed door identifier and a mobile device identifier. A control device determines, from information in the access request and stored information indicating which mobile devices have authority to access which doors, if access should be granted to the door corresponding to the hashed access device identifier from which the received information was generated. The received information may be hash of the mobile identifier and hashed door identifier.
Abstract:
Methods, systems, and devices are described for wireless communication. A serving base station may transmit a signal to user equipment (UE) using directional beamforming. The UE may receive the transmission from the serving base station and may also receive a signal from a neighbor base station using directional beamforming. The UE may then generate an interference report based on the two transmissions, and send report to the serving base station. The serving base station may generate a local interference graph based on the interference report, exchange interference information with the neighbor base station(s), and schedule subsequent transmissions to the UE based on the exchanged interference information. In some cases, the scheduling is based on distributed information exchange and prioritization. In other cases, the scheduling may be managed by a centralized controller.
Abstract:
A method of data encoding is disclosed. An encoder receives a set of information bits and performs an LDPC encoding operation on the set of information bits to produce a codeword based on a matched lifted LDPC code. The matched lifted LDPC code is based on a commutative lifting group and includes a number of parity bits and a submatrix to determine values of the parity bits. An order of the lifting group (Z) corresponds with a size of the lifting. A determinant of the submatrix is a polynomial of the form: ga+(g0+gL)P, where g0 is the identity element of the group, g0=gL2k, and P is an arbitrary non-zero element of a binary group ring associated to the lifting group.