Performance Evaluation of OFDM Amplify-and-Forward Relay System with Subcarrier Permutation

Enis KOCAN  Milica PEJANOVIC-DJURISIC  Diomidis S. MICHALOPOULOS  George K. KARAGIANNIDIS  

Publication
IEICE TRANSACTIONS on Communications   Vol.E93-B   No.5   pp.1216-1223
Publication Date: 2010/05/01
Online ISSN: 1745-1345
DOI: 10.1587/transcom.E93.B.1216
Print ISSN: 0916-8516
Type of Manuscript: PAPER
Category: Wireless Communication Technologies
Keyword: 
amplify-and-forward,  OFDM,  relay,  subcarrier permutation,  

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Summary: 
We perform error probability analysis of the uncoded OFDM fixed gain Amplify-and-Forward (AF) relaying system with subcarrier permutation (SCP). Two SCP schemes, named: the best-to-best SCP (BTB SCP) and the best-to-worst SCP (BTW SCP) are considered. Closed-form expressions for the bit error rate (BER) of the above SCP methods are derived. Numerical results manifest that these SCP schemes may outperform one another, depending on the average channel conditions of the links involved. That is, BTB SCP is better at low signal-to-noise ratio (SNR) values, while BTW SCP prevails in the medium and high SNR regime. Thus, it could be concluded that OFDM AF relaying systems may switch from the BTB SCP to BTW SCP in order to achieve optimum BER performance. Moreover, using the derived end-to-end SNR probability density functions (PDF), tight upper bounds for the ergodic capacities of both SCP schemes are obtained.