HARQ Retransmission Reduction via PAPR Management
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Solution Overview
Problem
Current wireless communication systems face inefficiencies in error correction due to high Peak-to-Average-Power Ratio (PAPR) in multi-carrier modulation techniques, leading to increased HARQ retransmissions which are computationally intensive and introduce latency.
Innovation Solution
Implementing a two-level error detection/correction system where the first level is less computationally intensive and performed at the front end of the demodulator, using Peak-to-Average-Power Reduction Management techniques such as Selective Mapping and Partial Transmit Sequences to reduce peak power, and the second level is more intensive and performed at the back end, thereby filtering out corrupted packets and reducing the need for unnecessary retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multi-carrier modulation techniques (OFDM/OFDMA) are used to improve spectral efficiency, then spectral efficiency is improved, but PAPR increases leading to higher error rates
Solution Approach 1:
The patent applies parameter changes by modifying the power distribution characteristics of the transmitted signal through PAPR reduction techniques. By changing the peak power parameter to be closer to the average power level, the system maintains spectral efficiency while reducing the harmful peak power excursions that cause intermodulation distortion and errors.
2Reliability
If PAPR management techniques (SM/PTS) are applied to reduce peak power, then error rate is reduced, but system complexity increases
Solution Approach 1:
The patent applies preliminary action by performing error detection at the front-end of the receiver before full signal processing. This preliminary check allows the system to identify and discard corrupted packets early, avoiding the need for complex retransmission protocols and reducing overall system complexity despite the added front-end detection capability.
Solution Approach 2:
The patent segments the error correction process into two distinct levels: a simple front-end detection mechanism that handles obvious errors, and a more sophisticated back-end correction mechanism for remaining errors. This segmentation allows each part to be optimized independently, reducing overall complexity.
3Reliability
If HARQ retransmissions are used to correct transmission errors, then error correction capability is improved, but latency and computational overhead increase
Solution Approach 1:
The patent applies partial action by implementing a two-level error correction approach where only the most critical errors are handled by the full HARQ retransmission process. The front-end detection handles simple errors locally, so that HARQ is invoked only for more severe cases, reducing the frequency and impact of retransmissions on latency.
Data Source
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Figure 3
Figure 4A
AI summary
Systems, methods and apparatuses for reducing HARQ retransmissions using peak power management techniques are presented. In one example, a receiver may perform multi-level error correction for reducing HARQ retransmissions. The receiver may include a Peak to Average Power Ratio Management Module (PAPR MM) decoder configured to perform a first level of error correction utilizing retransmissions originating at a front end of a distal transmitter. The receiver may further include a symbol demapping module connected to the PAPR MM decoder, a deinterleaver connected to the symbol demapping module, and a decoder connected to the deinterleaver and the PAPR MM decoder, where the decoder may be configured to perform a second level of error correction utilizing retransmissions originating at a back end of a distal transmitter. A transmitter for reducing HARQ retransmissions using PAPR techniques is also presented.