Rate Matching with Irregular Modulation for 5G Channel Coding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current channel coding methods, such as turbo codes used in LTE, may not meet the performance requirements for new use cases in 5G New Radio (NR) systems, particularly for ultra-low latency and massive machine-type communications.
Innovation Solution
A method for channel coding that involves dividing coded bits from a circular buffer into two parts and mapping them according to different modulation orders. The lengths of these parts are determined based on the modulation orders and derived from a length resulting from puncturing the coded bits using a rate-matching function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional turbo codes are used for channel coding in LTE systems, then the system maintains compatibility with existing infrastructure, but the performance is insufficient for new 5G use cases requiring ultra-low latency and massive machine-type communication
Solution Approach 1:
The patent changes the fundamental parameter of channel coding by transitioning from turbo codes to polar codes, which provide superior performance for 5G requirements. This parameter change enables both ultra-low latency and massive machine-type communication use cases while maintaining systematic approach to code design and rate matching
2Reliability
If coded bits are divided into multiple parts with different modulation orders, then the system achieves better performance optimization for diverse use cases, but the device complexity increases due to multiple modulation schemes
Solution Approach 1:
The patent segments the coded bit stream into multiple parts, where each part can be modulated with different modulation orders. This segmentation allows optimization for different use cases (e.g., ultra-low latency vs. massive machine-type communication) while maintaining a systematic framework. The divided coded bits are processed through separate rate matching functions with different parameters, enabling flexible adaptation without requiring complete system redesign
Solution Approach 2:
The patent introduces dynamic modulation order selection for different parts of the coded bit stream. Instead of using a fixed modulation scheme, the system dynamically assigns different modulation orders (e.g., QPSK, 16QAM, 64QAM) to different parts based on the specific use case requirements, achieving performance optimization while maintaining manageable complexity through structured dynamic adaptation
3Adaptability or versatility
If rate matching is performed with puncturing to achieve target code rates, then the system achieves flexible code rate adaptation, but the computational load increases in the rate matching process
Solution Approach 1:
The patent divides the rate matching process into multiple independent rate matching functions, each handling a specific part of the coded bit stream. Each rate matching function operates with its own parameters (e.g., different circular buffer sizes, different puncturing patterns), enabling flexible code rate adaptation for different parts while distributing the computational load across multiple simpler functions rather than one complex monolithic function
Solution Approach 2:
The patent applies different rate matching parameters and puncturing patterns to different parts of the coded bit stream based on local requirements. Each part undergoes rate matching with parameters optimized for its specific purpose, achieving overall system flexibility while reducing computational complexity by avoiding uniform complex processing across the entire bit stream
Data Source
Figure 1A
Figure 1B
Figure 1C
AI summary
A method and system for rate matching in a wireless communication system is disclosed. The method comprises receiving K information bits at a channel encoder and generating N output bits. The N output bits may be interleaved by an interleaver. In a HARQ retransmission the output bits may be placed into a circular buffer. The N output bits may be divided into two or more parts comprising at least a first part and a second part. The method further comprises mapping a first part of one or more parts of the N output bits to a M1 (=2m 1)-ary modulation and mapping a second part of one or more parts of the N output bits to a M2 (=2m 2 ))-ary modulation. The output bits may be transmitted by a wireless transmit/receive unit (WTRU), a base station, or the like.