LDPC Rate Matching with Bonus Symbols for Receiver Sensitivity
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Solution Overview
Problem
Existing LDPC rate matching schemes in wireless communication standards like IEEE 802.11n, 802.11ac, and 802.11ax face issues with receiver sensitivity due to discontinuities in the number of punctured bits per codeword, leading to inefficient decoding and increased parity puncture rates, especially for smaller payload sizes.
Innovation Solution
The introduction of additional LDPC symbols, referred to as bonus symbols, to adjust the number of available bits for error correction, reducing the number of punctured bits and improving receiver sensitivity by using a rate matching system that includes a RM controller, LDPC encoder, bit repeater, bit shortener, and parity puncturer to manage codeword sizes and parity bits.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing LDPC rate matching schemes are used, then the encoding process can be completed, but receiver sensitivity suffers due to discontinuities in the number of punctured bits per codeword
Solution Approach 1:
The patent introduces bonus symbols in advance before the actual encoding and rate matching process. These bonus symbols are added to the payload data before LDPC encoding, allowing the system to pre-adjust the total bit count and thereby control the number of punctured bits in subsequent rate matching operations, eliminating discontinuities in receiver sensitivity.
Solution Approach 2:
The patent modifies the parameter of available bits for error correction by introducing bonus symbols. This changes the total number of bits available for LDPC encoding, which directly affects the number of parity bits generated and subsequently the number of punctured bits during rate matching, thereby smoothing out discontinuities in receiver sensitivity across different payload sizes.
2Reliability
If the number of punctured bits is reduced, then receiver sensitivity improves, but the complexity of the rate matching system increases
Solution Approach 1:
By performing the bonus symbol addition before encoding, the system establishes the correct bit count early in the process. This preliminary action simplifies subsequent rate matching operations because the RM controller can work with predetermined parameters, reducing the need for complex real-time calculations and adjustments during the encoding and transmission process.
Solution Approach 2:
The patent segments the rate matching function into distinct components: bonus symbol addition, LDPC encoding, and controlled puncturing. This segmentation allows each component to be optimized independently, with the RM controller managing only the puncturing operation based on pre-calculated parameters, thereby reducing overall system complexity while maintaining improved receiver sensitivity.
3Reliability
If bonus symbols are added to adjust available bits, then parity puncture rate decreases, but the encoding process becomes more complex
Solution Approach 1:
The bonus symbols are added to the payload data before LDPC encoding begins. This preliminary addition establishes the correct total bit count that accounts for both the original payload and the bonus symbols, allowing the LDPC encoder to generate the appropriate number of parity bits in one pass without requiring complex iterative adjustments or multiple encoding stages.
Solution Approach 2:
By changing the parameter of available bits to include bonus symbols, the patent modifies the input to the LDPC encoder. This single parameter change propagates through the encoding process, automatically adjusting the number of parity bits generated and reducing the subsequent puncture rate, without requiring complex modifications to the encoding algorithm itself.
Data Source
AI summary
A system may include a transmitter and one or more processors. The one or more processors may be configured to identify a number of additional symbols to be added to existing symbols corresponding to payload data to be encoded. The one or more processors may be configured to calculate, based on a length of the payload data and the number of additional symbols, a number of available bits for error correction. The one or more processors may be configured to encode, via an low-density parity-check (LDPC) encoder, the payload data using an LDPC code to generate a codeword having a number of parity bits corresponding to the available bits. The one or more processors may be configured to transmit, via the transmitter, the encoded data.