H-ARQ Decoder Using Buffered State Information
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Solution Overview
Problem
Hybrid automatic repeat request (H-ARQ) systems face challenges in decoding corrupted packets due to unknown starting state information, leading to inefficiencies in decoding processes and increased iteration requirements.
Innovation Solution
Implementing a decoder with error checking logic and a buffer to store state information associated with received packets, allowing for the use of previously-buffered state information to decode retransmitted packets in H-ARQ mode, thereby determining the starting trellis state and reducing iteration operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If H-ARQ schemes combine newly-received packets with previously corrupted packets to decode, then signal sensitivity gain is achieved, but decoding complexity and iteration requirements increase due to unknown starting state information
Solution Approach 1:
The patent applies preliminary action by pre-calculating and storing state information (such as trellis states, soft bits, or syndrome values) in a buffer during the initial packet reception, even before retransmission occurs. This pre-computed state information is then reused during retransmission decoding, eliminating the need to restart decoding from scratch and reducing both complexity and iteration requirements while maintaining the signal sensitivity gain from combining packets.
2Reliability
If H-ARQ schemes store and combine coded bits from multiple transmissions, then correction performance is improved, but loss of time occurs due to buffering and combination operations
Solution Approach 1:
The patent applies discarding and recovering by selectively discarding redundant or outdated state information from the buffer when it is no longer needed for combination operations, and recovering only the essential state information required for the next decoding attempt. This selective management reduces the time spent on buffering and combination operations while maintaining the correction performance benefits of H-ARQ packet combining.
Data Source
AI summary
In the various embodiments, decoders, methods, systems and devices exploit state information associated with transmitted packets to facilitate decoding operations. Specifically, in at least some embodiments, packets are received by a receiver. If the packet is unable to be decoded because of corruption, state information associated with that packet is buffered at the receiver and used for subsequent decoding. A retransmitted packet is then received, checked for corruption and, if not corrupted, is decoded leveraging the previously-buffered state information associated with the corrupted packet. In an event that one or more retransmitted packets are corrupted, this process can be repeated a number of times.