BER-optimized power allocation for fading relay channels

Muhammad Mehboob Fareed, Murat Uysal

Research output: Contribution to journalArticlepeer-review


Optimum power allocation is a key technique to realize the full potentials of relay-assisted transmission promised by the recent information-theoretic results. In this paper, we present a comprehensive framework for power allocation problem in a single-relay scenario taking into account the effect of relay location. In particular, we aim to answer the two fundamental questions: Q1) How should the overall transmit power be shared between broadcasting and relaying phases?; Q2) In the relaying phase, how much power should be allocated to relay-todestination and source-to-destination links? The power allocation problem is formulated to minimize a union bound on the bit error rate (BER) performance assuming amplify-and-forward relaying. We consider both orthogonal and non-orthogonal cooperation protocols. Optimized protocols demonstrate significant performance gains over their original versions which assume equal sharing of overall transmit power between the source and relay terminals as well as between broadcasting and relaying phases. It is observed that optimized virtual (distributed) antenna configurations are able to demonstrate a BER performance as close as 0.4dB within their counterpart co-located antenna configurations.

Original languageEnglish (US)
Article number4543087
Pages (from-to)2350-2359
Number of pages10
JournalIEEE Transactions on Wireless Communications
Issue number6
StatePublished - Jun 2008


  • Distributed space-time codes
  • Pairwise error probability
  • Power allocation
  • Relay channels

ASJC Scopus subject areas

  • Computer Science Applications
  • Electrical and Electronic Engineering
  • Applied Mathematics


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