Polar Code Rate Matching Using Hadamard Row-Weight Selection
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Solution Overview
Problem
Traditional rate-matching schemes for polar codes in wireless communication systems, such as those used in NR and LTE, can lead to performance loss due to constraints on block length and available bandwidth, particularly when the size of the circular buffer is not a power of 2.
Innovation Solution
An efficient rate-matching scheme is proposed that selects bits for puncturing or shortening based on the row weights of a Hadamard matrix, allowing for flexible modification of encoded bits stored in a circular buffer to match the allocated transmission resources, thereby optimizing bit transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional rate-matching schemes are used for polar codes, then the encoding process can be completed, but performance loss occurs due to block length constraints and bandwidth limitations
Solution Approach 1:
The patent changes the parameter selection criteria for rate-matching from fixed or simple sequential selection to selection based on row weights of Hadamard matrix. This parameter change allows flexible adaptation to different block lengths and bandwidth conditions, resolving the contradiction between maintaining communication performance and handling block length constraints.
2Adaptability or versatility
If the circular buffer size is not a power of 2, then more flexible bandwidth allocation is possible, but traditional rate-matching schemes fail to optimize bit transmission
Solution Approach 1:
The patent introduces row weight-based parameter selection that works independently of circular buffer size being a power of 2. This allows the system to maintain high bit transmission efficiency regardless of whether the buffer size is a power of 2, thus resolving the contradiction between bandwidth flexibility and transmission efficiency.
Solution Approach 2:
The rate-matching scheme becomes dynamic by selecting bits based on calculated row weights rather than fixed patterns. This dynamic selection adapts to different buffer sizes and bandwidth allocations, maintaining optimization across varying system conditions.
3Productivity
If more bits are transmitted to fill available bandwidth, then bandwidth utilization improves, but decoding complexity and latency increase
Solution Approach 1:
By changing the selection parameter to row weights, the system can identify and transmit only the most important bits within the available bandwidth. This selective transmission maintains high bandwidth utilization while reducing the total number of bits that need decoding, thus reducing decoding latency.
Data Source
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AI summary
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.