Communication Link Retransmission for Fixed Latency
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Solution Overview
Problem
Existing communication systems fail to utilize communication links to their maximum bandwidth and maintain packet order while ensuring fixed latency, particularly in unpredictable wireless environments, due to inefficiencies in error detection and correction techniques like FEC and ARQ.
Innovation Solution
A communication system where packets are transmitted with a first error resistance level, erroneous packets are retransmitted with a higher error resistance level, and the retransmissions are prioritized to maintain original order and minimize latency, with control mechanisms to manage throughput and burst to approach the link's maximum capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmission requests are sent for erroneous packets, then data reliability is improved, but transmission delay increases
Solution Approach 1:
The system performs preliminary actions by sending retransmission requests immediately upon detecting erroneous packets, rather than waiting for the next scheduled transmission opportunity. This proactive approach reduces the overall delay by initiating retransmission processes as early as possible, thereby improving data reliability without excessive time loss.
Solution Approach 2:
The system dynamically adjusts the retransmission strategy based on link conditions and packet priority. By making retransmission decisions adaptive rather than static, the system can balance reliability requirements against delay constraints, sending retransmission requests only when necessary and prioritizing critical data packets.
2Productivity
If communication link utilization is increased to maximum capacity, then productivity is improved, but latency variance increases
Solution Approach 1:
The system changes key parameters such as modulation scheme, coding rate, and transmission power dynamically based on channel conditions. This allows the link utilization to be maximized under good conditions while maintaining acceptable latency performance by switching to more robust (but slower) transmission modes when errors occur, thereby reducing latency variance.
3Reliability
If error resistance level is increased for all packets, then data reliability is improved, but bandwidth utilization decreases
Solution Approach 1:
Instead of applying uniform high error resistance to all packets, the system applies differential error protection where only packets identified as erroneous or critical receive enhanced error resistance through retransmission with more robust encoding. This local quality approach maintains high reliability for problematic packets while preserving bandwidth utilization for the overall data stream.
4Reliability
If packet order is maintained through buffering, then data integrity is improved, but transmission latency increases
Solution Approach 1:
The system performs preliminary buffering of packets at the transmitter side before transmission, organizing them in the correct sequence in advance. This preliminary action allows the receiver to maintain packet order without extensive buffering, thereby reducing transmission latency while preserving data integrity.
Data Source
AI summary
A communication link comprising: a first transceiver configured to transmit a first set of packets at a predetermined rate with a first error resistance level, store the transmitted data in a buffer, receive a retransmission request, and retransmit the relevant data using one or more packets encoded with a second error resistance level that is higher than the first error resistance level. And a second transceiver configured to receive the first set of packets, detect an erroneous packet, request retransmission of the erroneous packet, and forward the data received in the packets according to its original order approximately after a fixed delay.