MIMO ACK/NACK Error Protection Using Nonlinear ARQ Code Sets
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Solution Overview
Problem
Current error protection schemes for ACK/NACK messages in MIMO wireless communications, such as those used in HSDPA, provide insufficient error protection for multiple MIMO streams, leading to higher error rates or increased transmit power requirements.
Innovation Solution
The implementation of nonlinear code sets with specific properties, such as C10,6,6 for two-stream MIMO, C10,10,5 for three-stream MIMO, and C10,16,4 for four-stream MIMO, which optimize the number of coding bits and ensure a minimum Hamming distance for reliable ACK/NACK signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional error protection schemes are used for ACK/NACK messages in MIMO wireless communications, then the system is simpler to implement, but error protection is insufficient leading to higher error rates
Solution Approach 1:
The patent changes the fundamental parameters of the coding scheme by transitioning from conventional linear codes to nonlinear code sets. This parameter change enables superior error protection performance (higher reliability) while maintaining practical implementability through carefully designed code structures with specific Hamming distance properties.
Solution Approach 2:
The patent performs preliminary design and optimization of nonlinear code sets before deployment. The code sets are pre-configured with specific properties (such as C10,6,6 for two-stream MIMO) to ensure optimal error protection. This preliminary action allows the system to achieve high reliability without requiring complex real-time computation during transmission.
2Reliability
If conventional error protection schemes are used, then implementation is easier, but transmit power requirements increase to maintain reliability
Solution Approach 1:
By changing from linear to nonlinear coding parameters, the patent achieves better error protection efficiency. The nonlinear code sets provide higher Hamming distances for the same code length, enabling reliable ACK/NACK signaling at lower transmit power levels compared to conventional schemes.
3Reliability
If more coding bits are used to improve error protection, then reliability increases, but the number of coding bits increases
Solution Approach 1:
The patent changes the coding parameters by using nonlinear code sets that achieve higher error protection with optimized code lengths. For example, the C10,6,6 code set provides robust protection for two-stream MIMO without requiring excessive coding bits, thus maintaining efficiency while improving reliability.
Data Source
AI summary
Error protection based on a nonlinear code set may be used in a multiple input multiple output (MIMO) radio communications system. A decoder decodes received MIMO data streams and generates an automatic repeat request (ARQ) message for data units received for the MIMO data streams for each transmission time interval. An encoder codes the ARQ message using a code word from a nonlinear code set. At the data transmitter, which transmits one or more data units in transmission time intervals from two or more MIMO data streams, the ARQ message associated with the transmitted data units is decoded using a code word from the nonlinear code set.