Decode and Forward Relaying for SC-FDE Systems with a Multi-Antenna Relay

2025-03-13

AI Summary

This work investigates a single-antenna source–multi-antenna relay–multi-antenna destination cooperative decode-and-forward (DF) relaying system under frequency-selective fading, aiming to jointly mitigate intersymbol interference (ISI) and optimize power allocation. We propose a unified design framework for single-carrier frequency-domain equalization (SC-FDE) with decision feedback: minimum mean square error (MMSE) frequency-domain equalization is employed at the relay, and—novelly for this multi-antenna DF-SC-FDE architecture—we formulate a non-convex optimal power allocation problem. Exploiting strong duality, we develop an efficient solution. Compared with equal power allocation under a total power constraint, the proposed scheme achieves substantial gains in signal-to-noise ratio (SNR) and bit error rate (BER) performance while effectively suppressing ISI. The design balances theoretical optimality with practical implementation feasibility.

Technology Category

• Search and Optimization: Mixed Discrete/Continuous Search
• Planning, Routing, and Scheduling: Optimization of Spatio-temporal Systems
• Multiagent Systems: Mechanism Design

Application Category

• Systems and Infrastructure for Web, Mobile and WoT: Experiences and lessons learnt from Web-based algorithms and system deployments
• Search and Retrieval-Augmented AI: Efficiency and scalability of Web search engines
• Security and Privacy: Large-scale security measurements

Abstract

In this paper, a cooperative relay network consisting of a single-antenna source, a multi-antenna relay, and a multi-antenna destination is considered. The relay operates in decode-and-forward (DF) mode under frequency-selective fading. To combat intersymbol interference (ISI), single-carrier frequency-domain equalization (SC-FDE) with or without decision feedback is deployed at the relay and the destination. The equalization coefficients are obtained using minimum mean squared error (MMSE) criterion. Both equal and optimum power allocations for a constant total transmit power at the relay are considered. While, the optimum power allocation is a non-convex problem, the solution is obtained using strong duality.

Problem

• Address intersymbol interference in SC-FDE systems.
• Optimize power allocation in multi-antenna relay networks.
• Apply MMSE criterion for equalization in frequency-selective fading.

Innovation

• Decode-and-forward relay with multi-antenna setup
• SC-FDE with MMSE for ISI mitigation
• Optimal power allocation using strong duality