LDPC Circular Buffer Rate Matching for Variable Code Rates
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Solution Overview
Problem
Current low-density parity check (LDPC) codes in wireless communication systems face challenges in achieving high throughput with efficient hardware utilization, particularly in supporting a wide range of information block lengths and code rates, which is essential for next-generation networks like 5G New Radio.
Innovation Solution
The implementation of a configurable circular buffer for LDPC encoding, allowing for flexible adjustment of the mother code rate and buffer lengths to accommodate various information block sizes and code rates, enabling efficient LDPC coding and decoding processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional LDPC codes are used with fixed code rates, then the implementation is simple, but the system cannot support a wide range of code rates and information block lengths required for 5G networks
Solution Approach 1:
The patent implements a configurable circular buffer system where the buffer length and mother code rate can be dynamically adjusted based on the required code rate and information block length. This allows the LDPC encoder to adapt to different 5G service requirements (eMBB, URLLC, mMTC) without requiring multiple fixed implementations, thus improving versatility while managing complexity through a unified dynamic structure.
Solution Approach 2:
The system changes key parameters including the circular buffer length (N), mother code rate (Rmother), and information block length (K) to support different code rates. By parameterizing the LDPC code structure rather than fixing it, the system can efficiently support a wide range of code rates from 1/5 to 4/5 and information block lengths from 64 to 8192 bits, meeting diverse 5G requirements.
2Length of moving object
If the circular buffer length is increased to support larger information blocks, then the maximum code length increases, but the hardware resource utilization decreases
Solution Approach 1:
The circular buffer length is made dynamic and configurable rather than fixed. The buffer length N is calculated based on the maximum code length requirement Nmax = Kmax/Rmin* and the selected mother code rate. This allows the hardware to allocate buffer resources efficiently for different code rates and block sizes, improving hardware utilization while supporting various maximum code lengths required by different 5G services.
Solution Approach 2:
A single configurable circular buffer structure serves multiple functions by adapting to different information block lengths and code rates. The same hardware implementation can support both small blocks (64 bits) and large blocks (8192 bits) by reconfiguring the buffer parameters, eliminating the need for multiple dedicated hardware structures and thus improving overall hardware resource utilization.
3Reliability
If the mother code rate is reduced to improve error correction performance, then the coding gain increases, but the throughput decreases
Solution Approach 1:
The mother code rate Rmother is configured based on the required code rate R and information block length K to achieve the desired balance between reliability and throughput. By selecting appropriate mother code rates from a set of predefined values and adjusting the circular buffer parameters accordingly, the system can optimize error correction performance for critical services while maintaining high throughput for data-intensive services.
Solution Approach 2:
The mother code rate is made dynamically selectable rather than fixed, allowing the system to adapt to different service requirements. For services requiring high reliability (e.g., URLLC), a lower mother code rate can be selected to improve error correction. For services requiring high throughput (e.g., eMBB), a higher mother code rate can be selected. This dynamic adaptation resolves the trade-off between reliability and throughput.
Data Source
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AI summary
Aspects of the present disclosure relate to low density parity check (LDPC) coding utilizing a configurable circular buffer for rate matched transmissions such as IR-HARQ transmission. The circular buffer may be configured based on a selected mother code rate and a fixed circular buffer length. For example, the respective sizes of the systematic and parity bit sections of the circular buffer may be variable based on the selected mother code rate.