Incremental Redundancy Retransmission for Fragmented Packets
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Solution Overview
Problem
Current retransmission techniques in wireless telecommunications networks, such as conventional ARQ, do not effectively adapt to varying channel conditions, leading to suboptimal performance in terms of packet error rate, delay, and jitter at the IP level, especially when dealing with fragmented packets.
Innovation Solution
Implementing a retransmission method with incremental redundancy at the MAC layer, where packets are coded using a convolutional coder to generate redundancy blocks, allowing for adaptive correction capacity based on the number of fragments transmitted, and managing retransmissions accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ARQ retransmission technique is used at MAC layer, then implementation is simple, but packet error rate, delay and jitter performance at IP level is suboptimal
Solution Approach 1:
The patent implements dynamic adaptation of retransmission strategies at the MAC layer. The system dynamically adjusts the number of redundancy blocks (M) based on channel conditions and packet characteristics. The incremental redundancy mechanism allows the system to transmit different amounts of redundancy information adaptively, transforming a static ARQ system into a dynamic one that optimizes IP-level performance while managing complexity through intelligent control
Solution Approach 2:
The patent changes key parameters of the retransmission system including the code rate (K/M), the number of redundancy blocks (M), and the incremental redundancy amount. By varying these parameters based on channel quality and packet importance, the system achieves better IP-level reliability without requiring complete redesign of the MAC layer architecture
2Reliability
If incremental redundancy with convolutional coding is implemented, then packet error rate is reduced, but processing complexity and computational load increase
Solution Approach 1:
The patent segments the redundancy information into multiple blocks (M blocks) that can be transmitted incrementally. Each block contains a portion of the total redundancy information needed for error correction. This segmentation allows the receiver to accumulate redundancy information over multiple transmissions and progressively improve decoding capability, reducing the immediate processing burden while maintaining high reliability
Solution Approach 2:
The system dynamically adjusts the coding parameters including the code rate and the amount of redundancy transmitted in each retransmission. The convolutional encoder parameters are adapted based on channel conditions, allowing the system to optimize the trade-off between error correction capability and processing complexity in real-time
3Reliability
If retransmission credit counter C_MSDU is increased to allow more retransmissions, then reliability improves, but delay increases
Solution Approach 1:
The patent implements dynamic management of the retransmission credit counter C_MSDU. The counter value and the number of allowed retransmissions are adjusted dynamically based on channel conditions, packet type, and quality of service requirements. This dynamic control allows the system to achieve high reliability when needed while minimizing delay in good channel conditions
Solution Approach 2:
The system transmits incremental redundancy in partial amounts across multiple transmissions rather than requiring complete retransmission. The receiver can successfully decode the packet after receiving a portion of the redundancy information, reducing the effective number of retransmissions needed and thereby reducing delay while maintaining reliability
Data Source
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AI summary
The invention relates to an incremental redundancy retransmission method adapted for the transmissions of packets that can be fragmented into N i-indexed packets.