Receiver Channel Estimation Using Hybrid ARQ Data Hypotheses
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Solution Overview
Problem
Existing channel estimation techniques in radio communications systems face challenges such as high computational complexity, high processing delay, and low information data throughput due to the need for increased pilot data content, which limits their practical implementation and performance.
Innovation Solution
The proposed solution involves using data symbol hypotheses from a previous data block as reference symbols for channel estimation in a subsequent data block, allowing for more accurate channel estimation without increasing pilot data content, thereby improving decoding performance and reducing retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If more pilot data is included in the transmitted signal, then channel response estimation accuracy is improved, but information data throughput is reduced
Solution Approach 1:
The invention performs preliminary channel estimation using pilot symbols first, then uses the initial data symbol estimates as additional reference symbols for refined channel estimation. This two-stage approach allows accurate channel estimation without requiring increased pilot data content, thus maintaining information data throughput while improving measurement precision.
Solution Approach 2:
The invention feeds back the initially estimated data symbols to the channel estimator as additional reference symbols. This feedback mechanism enables the channel estimator to use both pilot symbols and data symbols for refined estimation, improving channel response accuracy without increasing pilot data content or reducing throughput.
2Reliability
If iterative channel estimation with turbo decoding feedback is used, then channel response estimation reliability is improved, but computational complexity and processing delay increase
Solution Approach 1:
The invention performs a preliminary channel estimation using pilot symbols before turbo decoding, then uses the initial data symbol estimates for refined estimation. This preliminary action provides reliable channel estimates without requiring multiple iterative passes through the entire decoding process, reducing computational complexity while maintaining reliability.
Solution Approach 2:
The invention extracts initial data symbol estimates from the turbo decoding process and uses them as reference symbols for refined channel estimation. This extraction approach provides reliable channel estimates without requiring the full iterative feedback loop, thereby reducing processing delay and computational complexity.
3Reliability
If iterative channel estimation with turbo decoding feedback is used, then channel response estimation reliability is improved, but memory requirements increase
Solution Approach 1:
The invention extracts initial data symbol estimates from the turbo decoding process and uses them immediately for refined channel estimation. This extraction approach provides reliable channel estimates without requiring storage of all received symbols and intermediate results, thereby reducing memory requirements while maintaining reliability.
4Device complexity
If combined pilot aided and decision directed channel estimation is used, then device complexity is reduced, but convergence speed decreases
Solution Approach 1:
The invention performs preliminary channel estimation using pilot symbols before using data symbols for refined estimation. This preliminary action establishes an accurate initial channel estimate that converges quickly, avoiding the slow convergence issues of decision-directed methods while maintaining low computational complexity.
Data Source
AI summary
The invention relates to channel estimation in a receiver. The channel estimation for a current data block is based on a previous data block, where the two data blocks are based on common information. Data symbol hypotheses of the previous data block can be forwarded to a channel estimator and used as known reference symbols when estimating the channel response for the current block. Alternatively, a combination of the data symbol hypotheses and preliminary data symbol estimates of the current block are used as reference symbols in a refined channel estimation for the current block. Data bit hypotheses of the previous block can also be input as a priori data in a preliminary demodulation of the current block. The demodulator output is used as reference data in a refined channel estimation for the current block. The invention is well-adapted for usage in connection with Hybrid ARQ.