Rate Matching Patterns for Reliable Uplink Control Information
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Solution Overview
Problem
In mobile communication systems, particularly in UMTS with E-DCH, there is a need for improving the reliability of transmitting control information such as scheduling grants, which are crucial for efficient radio resource allocation and HARQ processes, but conventional rate matching techniques lead to high BLER deviations and performance degradation due to uneven Bit Error Rates across small block sizes.
Innovation Solution
The implementation of specific rate matching patterns that minimize Bit Error Rate (BER) variations at each bit position within a block, combined with convolutional coding and UE-ID specific CRCs, to enhance the reliability of transmitting control information, specifically for small block sizes like the E-AGCH, by puncturing or repeating bits according to predetermined patterns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rate matching techniques are used for small block sizes, then the transmission process can be completed, but high BLER deviations and performance degradation occur due to uneven Bit Error Rates across different bit positions
Solution Approach 1:
The patent applies local quality by implementing position-dependent rate matching patterns where different bit positions within a block are treated differently. Specifically, bits at positions more susceptible to errors (such as at block boundaries or specific indices) are protected through repetition or less aggressive puncturing, while other positions use standard rate matching. This creates non-uniform protection across the block that compensates for the uneven BER distribution inherent in conventional techniques, thereby reducing BLER deviation and improving overall reliability without requiring a complete change to the rate matching framework
Solution Approach 2:
The patent changes the rate matching parameters dynamically based on block position and size. Instead of applying a fixed rate matching pattern to all blocks, the system adjusts the puncturing and repetition patterns according to the specific bit position within the block and the block size. This involves modifying the rate matching pattern selection and the degree of puncturing/repetition applied at different positions, effectively changing the code rate locally to optimize BER uniformity across the entire transmitted block
2Reliability
If control information is transmitted with high reliability requirements, then transmission accuracy improves, but transmission time and resource overhead increase
Solution Approach 1:
The patent applies partial action by implementing selective repetition only for specific bit positions that exhibit higher error rates in conventional rate matching, rather than repeating all bits. The rate matching pattern selectively identifies and protects vulnerable positions (such as boundary bits or positions with historically higher BER) while applying minimal or no repetition to other positions. This partial protection approach achieves sufficient reliability improvement for control information without the full time overhead of universal repetition, balancing reliability enhancement with transmission efficiency
Data Source
AI summary
A method and apparatus for transmitting control information of a small block size with high reliability in a mobile communication system supporting uplink packet data service are provided. A 6-bit Absolute Grant indicating an allowed maximum data rate for uplink packet data transmission is generated and a 16-bit User Equipment Identifier Cyclic Redundancy Check is generated by combining a Cyclic Redundancy Check with a User Equipment Identifier. The User Equipment Identifier specific Cyclic Redundancy Check and 8 tail bits are added to the 6-bit Absolute Grant and the added bits are encoded at a coding rate of 1/3. The resulting 90 coded bits are rate-matched according to a predetermined rate matching pattern and transmitted to a User Equipment. The rate matching pattern is {1, 2, 5, 6, 7, 11, 12, 14, 15, 17, 23, 24, 31, 37, 44, 47, 61, 63, 64, 71, 72, 75, 77, 80, 83, 84, 85, 87, 88, 90}.