Circular Buffer Redundancy Version Layout for HARQ Rate Matching
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Solution Overview
Problem
Existing communication systems face inefficiencies in implementing rate matching algorithms, particularly in Hybrid Automatic Repeat Request (HARQ) operations, due to the inflexibility and implementation complexity of prior methods, which can lead to overlapping transmissions and reduced system performance.
Innovation Solution
A method and apparatus for assigning redundancy versions to a circular buffer, where redundancy versions are defined to start at specific positions within the buffer, allowing for easier implementation of HARQ and supporting a large number of input block sizes with circular buffer rate matching, using a virtual circular buffer concept that directly generates desired output bits without physical storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a circular buffer based rate matching algorithm is used, then flexibility and performance are improved, but implementation complexity increases due to difficulty in implementing HARQ with evenly distributed RV starting positions
Solution Approach 1:
The patent applies asymmetry by changing the distribution pattern of redundancy version starting positions from uniform/even distribution to a specific non-uniform pattern defined by the formula N_cb/8 × (i + 3/8). This asymmetric distribution simplifies the HARQ implementation by ensuring that RV starting positions align with specific boundaries in the circular buffer, making it easier to implement while maintaining flexibility.
2Adaptability or versatility
If a rule-based method stepping through codeword bits is used, then flexibility is improved, but implementation efficiency deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-defining the circular buffer structure and the specific starting positions for redundancy versions before the actual rate matching operation. The formula N_cb/8 × (i + 3/8) pre-calculates optimal starting positions, eliminating the need for step-by-step bit examination during transmission and significantly improving implementation efficiency while maintaining flexibility.
3Adaptability or versatility
If puncturing or repetition patterns are defined for every information block size and code rate, then coverage is improved, but device complexity becomes impractical
Solution Approach 1:
The patent applies universality by creating a single circular buffer structure that serves all information block sizes and code rates. The universal formula N_cb/8 × (i + 3/8) can be applied regardless of the specific block size or code rate, eliminating the need for separate puncturing or repetition patterns for each combination and making the system practical for thousands of combinations.
Data Source
AI summary
During operation of a transmitter a circular buffer is created where only column tops of the circular buffer are defined as a starting position for a redundancy version. Where the circular buffer is in sequence format, all possible redundancy versions are at positions ┌Kstream/32┐(12×i+σ), i=0, 1, . . . , 7 where σ indicates the column index of the starting position of the first RV (RV0).