WCDMA MIMO CQI Coding with Higher Hamming Distance Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current WCDMA systems with MIMO technology face challenges in reliably transmitting channel quality indicators (CQI) and antenna weight indicators (AWI) due to insufficient channel coding protection, resulting in weaker protection for CQI information bits compared to earlier releases, requiring more power to transmit detailed MIMO CQI reports.
Innovation Solution
A (20,10,6) code is introduced using a quadratic residue generator matrix derived from the Golay code, providing a minimum Hamming distance of 6 for the CQI/AWI codebook, which improves the protection of CQI information bits by allowing the receiver to correct two erroneous bits during hard-decision decoding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a (20,10,4) code is used for MIMO CQI feedback, then the feedback message can be transmitted, but the channel coding protection is insufficient requiring more transmission power
Solution Approach 1:
The patent changes the key parameter of the channel code from minimum Hamming distance 4 to minimum Hamming distance 6. This parameter change in the code structure provides stronger error protection capability, allowing reliable CQI transmission with reduced power requirements while maintaining the same code length and rate.
2Productivity
If more detailed CQI reporting is implemented for MIMO, then spectral efficiency increases, but the feedback message length increases requiring more coding protection
Solution Approach 1:
The patent applies parameter changes to the channel code by selecting a code with minimum Hamming distance 6 instead of 4. This enables the system to maintain reliable transmission for the increased 10-bit feedback message (double the original CQI bits) required for MIMO operations, thereby supporting higher spectral efficiency with adequate protection.
Data Source
Figure 1a~1b
Figure 2a~2b
Figure 3
AI summary
A block coding method and system for improving the reliability of Channel Quality Indicators (CQI) and antenna weight Indicators (AWI) reporting. A user terminal first generates 8-bit CQI and 2-bit AWI. A codeword generator produces a codeword responsive to these 10 CQI/AWI bits using a codebook or a generator matrix of a (20, 10, 6) code. The (20, 10, 6) code has a minimum Hamming distance of 6 The encoded codeword is transmitted to a receiver for decoding utilizing an identical (20, 10, 6) codebook.