Intra-Session Network Coding for Wireless Throughput
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Solution Overview
Problem
Existing network coding systems for wireless networks, such as COPE, experience performance degradation due to non-negligible loss rates, leading to disabled network coding when loss rates exceed a threshold, which limits the benefits of opportunistic listening and coding.
Innovation Solution
Incorporating intra-session network coding to generate parity packets based on loss rates, combining with inter-session network coding to enhance wireless network throughput even in high loss conditions, using a combination of stateful and stateless schemes to determine redundancy and packet flow coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If inter-session network coding is used to improve network throughput, then packet delivery efficiency is improved, but performance degrades when loss rates exceed a threshold
Solution Approach 1:
The patent segments the network coding function into two distinct components: intra-session coding (using XOR operations on packets from the same session) and inter-session coding (using linear combinations across different sessions). This segmentation allows each component to address specific aspects of the problem - intra-session coding handles packet loss recovery within a session, while inter-session coding optimizes throughput by utilizing overheard packets from other sessions.
Solution Approach 2:
The patent creates a composite network coding scheme that combines intra-session and inter-session coding mechanisms. This composite approach integrates the loss-resilient properties of intra-session coding with the throughput-optimizing properties of inter-session coding, resulting in a system that maintains performance stability even when packet loss rates exceed traditional thresholds.
2Reliability
If parity packets are generated to correct packet loss, then reliability is improved, but network overhead increases
Solution Approach 1:
The patent merges the functions of loss correction and throughput optimization by combining intra-session parity packet generation with inter-session packet combining. Instead of treating these as separate functions requiring independent resources, the system integrates them so that parity packets generated for loss correction can also be combined with packets from other sessions, thereby correcting packet loss while minimizing additional network overhead.
3Productivity
If opportunistic listening is enabled to improve throughput, then network efficiency is improved, but dependency on exact overheared packet knowledge increases
Solution Approach 1:
The patent extracts the critical function of opportunistic listening from the complex tracking and state management requirements of traditional COPE systems. By focusing on generating intra-session parity packets based on locally available information and combining them with inter-session packets, the system maintains the throughput benefits of opportunistic listening while eliminating the need for complex tracking of which specific packets have been overheard by which nodes.
Data Source
AI summary
Methods and apparatus to utilize network coding in a wireless network are disclosed. A disclosed example method includes receiving a first packet flow at a first node from a second node that is one-hop away from the first node, the first packet flow originating at a first source, receiving a second packet flow at the first node from a third node that is one-hop away from the first node, the second packet flow originating at a second source, generating, for the first packet flow, first intra-session parity packets using intra-session network coding and generating, for the second packet flow, second intra-session parity packets using intra-session network coding, the first and second intra-session parity packets being generated based on loss rates of links between the first and second nodes and the first and third nodes, and between the first node and a fourth node and between the first node and a fifth node, the fourth and fifth nodes being one-hop away from the first node, and combining at the first node the first and second packet flows and the first and second intra-session parity packets into a combined packet flow using inter-session network coding.