Two-Way Wireless Relay Transmission Using XOR Network Coding
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Solution Overview
Problem
Existing two-way wireless relay transmission technologies based on Decode-and-Forward (DF) and Digital Network Coding (DNC) face reduced transmission performance due to multiple retransmissions and the possibility of uncorrectable transmission errors, especially in networks with a large number of relay nodes, leading to suboptimal throughput under non-ideal channel conditions.
Innovation Solution
A method that avoids retransmitting error data packets in an n-relay two-way wireless transmission network, utilizing packet buffers and XOR operations to ensure each terminal node receives unique erroneous data packets, thereby preventing error propagation and maintaining optimal throughput of 0.667 packets/time slots without retransmissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If retransmission mechanisms are used to correct transmission errors in two-way wireless relay networks, then transmission reliability is improved, but transmission throughput decreases due to multiple retransmissions and time slot consumption
Solution Approach 1:
The patent converts the harmful effect of transmission errors into a beneficial outcome by using XOR network coding. When errors occur, the coded packets contain redundant information that allows the destination to identify and correct errors without requiring retransmission. The error propagation that would normally be harmful is transformed into an opportunity for error detection and correction through the mathematical properties of XOR operations on coded packets.
Solution Approach 2:
The patent applies preliminary error prevention measures by encoding packets with XOR operations before transmission. This preliminary coding ensures that even if transmission errors occur, the destination can recover the original data without needing retransmission. The error correction capability is built into the transmitted packets themselves, preventing the need for subsequent retransmission actions.
2Area of stationary object
If traditional DF and DNC relay transmission is used in networks with many relay nodes, then network coverage is improved, but transmission throughput decreases inversely proportional to the number of relay nodes
Solution Approach 1:
The patent merges multiple relay nodes into a cooperative network coding system where all relays transmit coded versions of the same data simultaneously or in coordinated fashion. Instead of sequential forwarding through each relay (which causes throughput to decrease with more relays), the relays work together to provide redundant coded information, maintaining high throughput while extending network coverage.
Solution Approach 2:
The patent makes each relay node universal by enabling them to perform the same network coding function regardless of their position in the network. Each relay applies the same XOR coding operation to incoming packets, making the relay nodes interchangeable and allowing the network to scale without degrading throughput performance. This multi-functional approach allows any relay to contribute equally to both coverage extension and throughput maintenance.
3Productivity
If ANC technology is used for two-way wireless relay transmission, then transmission throughput is improved, but system complexity increases due to requirements for precise self-information cancellation and accurate channel state estimation
Solution Approach 1:
The patent uses simple XOR coding operations that can be implemented with minimal computational resources, replacing the complex channel state estimation and self-information cancellation required by ANC. The coding scheme is deliberately simple and robust, sacrificing the theoretical optimality of ANC for practical implementability and lower complexity, while still achieving good throughput performance in real-world conditions.
Data Source
AI summary
A two-way wireless relay transmission method suitable for multiple relay nodes proposes a transmission solution based on a Decode-and-Forward (DF) technology and Network Coding (Network Coding, NC) technology suitable for a two-way wireless relay network. The method has an advantage of achieving a maximum spectrum efficiency based on the DF technology, and proposes a retransmission-free error control solution to avoid a problem of error spreading brought about by the NC technology to obtain an effective transmission throughput that is superior to existing solutions.