Convolutional Code Rate Matching for Flexible HARQ Puncturing
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Solution Overview
Problem
Existing methods for matching encoding rates to over-the-channel transmission rates in communication systems, particularly for convolutional codes, are inflexible and complicate incremental redundancy hybrid automatic repeat request (HARQ) systems, leading to performance losses due to overlapping puncturing patterns and limited code rate flexibility.
Innovation Solution
A method involving convolutional encoding, interleaving, multiplexing, and symbol addition/removal to generate a punctured symbol vector that matches the over-the-channel transmission rate, ensuring equal symbol contribution from each interleaved stream, allowing for flexible code rate adjustment and improved performance in convolutional codes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional puncturing patterns are used to match encoding rates to over-the-channel transmission rates, then rate matching can be achieved, but the system becomes inflexible when introducing new data rates and encoding rates
Solution Approach 1:
The patent changes the fundamental parameter of rate matching from using fixed puncturing patterns to using a systematic approach where the information vector is divided into blocks, encoded with convolutional codes, and then punctured based on calculated parameters (N, M, L) that can be adjusted for any desired code rate. This allows continuous adaptation to different data rates and encoding rates without requiring new puncturing patterns for each combination.
2Reliability
If traditional puncturing patterns are used for incremental redundancy HARQ, then rate matching is achieved, but performance is degraded due to overlapping puncturing patterns
Solution Approach 1:
The patent applies preliminary action by pre-calculating the puncturing parameters (N, M, L) based on the desired code rate and information block size before encoding. This ensures that subsequent transmissions in incremental redundancy HARQ can be properly coordinated without overlapping issues, as the puncturing pattern is determined in advance rather than being applied ad-hoc for each transmission.
Solution Approach 2:
The patent introduces dynamics by making the puncturing pattern adaptable to different transmission scenarios. The parameters N, M, and L can be dynamically adjusted based on the current transmission's requirements, allowing the system to optimize performance for each transmission while maintaining consistency across multiple transmissions in HARQ.
3Adaptability or versatility
If fixed puncturing patterns are applied to match encoding rate to transmission rate, then rate matching is achieved, but the system lacks flexibility for different information block sizes
Solution Approach 1:
The patent enables parameter changes by allowing the puncturing parameters (N, M, L) to be calculated based on the actual information block size and desired code rate. This means the system can adapt to different information block sizes while maintaining precise code rate control, as the parameters are derived from the specific transmission requirements rather than being fixed.
Data Source
AI summary
A method and apparatus for encoding and decoding data is described herein. During operation, data enters a convolutional encoder (101). The encoder encodes the information bits from the data at encoding rate (1/R0) to produce data symbols vectors P0, P1, . . . , PR0. Vectors P1, . . . , PR0 are each interleaved separately to form vectors P0′, P1′, . . . , PR0′. A multiplexer (105) multiplexes P0′, P1′, . . . , PR0′ to produce vector Q. The multiplexed interleaved symbols Q are input into symbol adder/remover (107) where appropriate symbols are added or removed to match an over-the-channel transmission rate. Finally, vector Q′ is transmitted via over-the-channel transmission.