LDPC concatenation rules for IEEE 802.11n system with packets length specific in octets
AssigneeSamsung Electronics Co., Ltd.
InventorsHuaning Niu, Chiu Ngo
Life of this patent
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Abstract
An improved LDPC encoding with concatenation rule and code size with packet lengths specified in octets is provided. The LDPC block size is selected to be an integer number of OFDM tones. The concatenation rule is an improvement of the shortening and puncturing scheme for low data rate. The improvement is two fold. First, the code length is selected based on the number of transmitted information bits in octets (HTLENGTH). Second, it is determined whether one extra OFDM symbol padding should be added based on the number of shortening bits in the last codeword and the available padding bits in the last OFDM symbol.
Claims28
A method of concatenation for Low Density Parity Check (LDPC) encoding in an Orthogonal Frequency Division Multiplexing (OFDM) wireless system, comprising:
- selecting codewords based on the data packet payload size, wherein the payload size is the number of transmitted information bits in octets;
- and
- for transmission rates below a threshold, applying shortening and puncturing across all codewords within the packet to minimize the extra OFDM padding while maintaining the coding performance, and
- for transmission rates above the threshold, applying only shortening across all codewords within the packet to minimize OFDM symbol padding.
A Multiple Input, Multiple Output (MIMO) Orthogonal Frequency Division Multiplexing (OFDM) wireless communication system comprising:
- a transmitter including an Low Density Parity Check (LDPC) encoder that encodes data using LDPC codes, wherein the encoder utilizes concatenation rules for LDPC encoding by:
- selecting codewords based on the data packet payload size, wherein the payload size is the number of transmitted information bits in octets, and for transmission rates below a threshold the encoder applies shortening and puncturing across all codewords within the packet to minimize the extra OFDM padding while maintaining the coding performance, and for transmission rates above the threshold the encoder applies only shortening across all codewords within the packet to minimize OFDM symbol padding.
A wireless transmitter comprising:
- a Low Density Parity Check (LDPC) encoder that encodes data using LDPC codes, wherein the encoder utilizes concatenation rules for LDPC encoding by:
- selecting codewords based on the data packet payload size, wherein the payload size is the number of transmitted information bits in octets, and for transmission rates below a threshold applying shortening and puncturing across all codewords within the packet to minimize the extra OFDM padding while maintaining the coding performance, and for transmission rates above the threshold applying only shortening across all codewords within the packet to minimize OFDM symbol padding.
A wireless receiver comprising:
- a decoder that performs Low Density Parity Check (LDPC) decoding by cropping a received packet including transmitted information bits in octets to an N-bit codeword, for the last codeword, if the number of bits is greater than parity bits length (M), the decoder adds padding zeros to the N bits, and decodes the result, otherwise if the number of bits is not greater than parity bits length (M), the decoder adds padding zeros to the end of the N bits without performing decoding, wherein the decoder selects a codeword of the largest possible code size according to the payload size.
An Orthogonal Frequency Division Multiplexing (OFDM) wireless system where the packet length is specified in OFDM symbols, comprising:
- a transmitter, the transmitter comprising:
- an encoder that performs Low Density Parity Check (LDPC) encoding in the system wherein the payload size is the number of transmitted information bits in octets;
- and
- a shortening unit coupled to a puncturing unit, wherein for transmission rates below a threshold the shortening unit and puncturing unit apply shortening and puncturing across all codewords within the packet to minimize OFDM symbol padding, and for transmission rates above the threshold the shortening unit applies only shortening across all codewords within the packet to minimize OFDM symbol padding for high transmission rates;
- and
- a receiver, the receiver comprising:
- a decoder performs LDPC decoding by cropping a received packet to an N-bit codeword, for the last codeword, if the number of bits is greater than parity bits length (M), the decoder adds padding zeros to the N bits, and decodes the result, otherwise if the number of bits is not greater than parity bits length (M), the decoder adds padding zeros to the end of the N bits without performing decoding.
Dependencies are inferred from the claim text.