Source Antenna Switching for Non-Orthogonal Decode-and-Forward Diversity
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Solution Overview
Problem
Conventional non-orthogonal protocols in cooperative networks do not effectively increase the diversity order due to the source-destination channel being the same at both phases, limiting the enhancement of diversity order despite using multiple relay nodes.
Innovation Solution
A source antenna switching scheme that utilizes two transmitting antennas in each RF chain, allowing one antenna to transmit signals to both the relay and destination nodes and the other to cooperate with the relay node's antennas, employing a near ML decoding method to enhance diversity order.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional non-orthogonal protocols are used with multiple relay nodes, then the system can establish additional independent paths for cooperative diversity, but the diversity order cannot be effectively increased because the source-destination channel remains the same at both phases
Solution Approach 1:
The patent applies antenna switching at the source node to dynamically change the transmission path between phases. In the first phase, one antenna transmits to both relay and destination. In the second phase, a different antenna transmits to the relay, creating dynamic path variation that increases diversity order while maintaining protocol simplicity
Solution Approach 2:
The patent segments the source node's transmission function across multiple antennas and phases. By dividing the transmission task among different antennas in different phases, the system creates independent paths that contribute to higher diversity order without requiring complex channel changes
2Reliability
If source antenna switching is implemented to increase diversity order, then error-free performance improves, but the decoding complexity increases due to the need to process multiple antenna paths
Solution Approach 1:
The patent employs a near-maximum likelihood decoding method that uses simplified, lower-cost computation instead of full maximum likelihood decoding. This approximate decoding approach achieves sufficient performance for antenna switching protocols while significantly reducing the computational complexity required to process multiple antenna paths
Solution Approach 2:
The patent changes the decoding parameter from exact maximum likelihood to near-maximum likelihood, accepting a small performance penalty in exchange for dramatically reduced complexity. This parameter change enables practical implementation of antenna switching without requiring excessive computational resources
3Reliability
If additional relay nodes are added to increase diversity order, then more independent paths are created, but the system complexity and hardware requirements increase
Solution Approach 1:
The patent makes the source node's antennas multi-functional by having each antenna participate in both direct transmission to the destination and relay transmission in different phases. This multi-functionality allows the system to achieve high diversity order using existing components rather than adding separate dedicated paths for each relay node
Solution Approach 2:
The patent uses dynamic antenna switching at the source node to create different transmission paths without adding physical relay nodes. By dynamically assigning different antennas to different transmission tasks across phases, the system achieves the diversity benefits of multiple relay nodes while using the same physical infrastructure
Data Source
AI summary
The present invention relates to a source antenna switching scheme for a non-orthogonal protocol; and more particularly, to a source antenna switching scheme for a non-orthogonal protocol, which transmits a signal of a source node to a destination node through a relay node. The present invention provides a source antenna switching scheme for a non-orthogonal decode-and-forward protocol that can acquire a greater diversity than the conventional NDF protocol. In other words, the present invention provides a source antenna switching scheme for a non-orthogonal decode-and-forward protocol that can increase a diversity order by adding a reasonable priced antenna instead of expensive hardware such as an RF chain when there are a plurality of antenna in the RF chain.