Wireless transmissions with combined gain relays over fading channels

Theodoros A. Tsiftsis, George K. Karagiannidis, Stavros A. Kotsopoulos

Research output: Chapter in Book/Report/Conference proceedingChapter

3 Citations (Scopus)


We present a dual-hop relayed wireless communication system where the gain of the relay, called combined gain relay (CGR), is produced after combining the channel state information from both hops, depending on the mean hop's signal-to-noise ratio (SNR). The proposed scheme can be efficiently applied in dual-hop transmissions with unbalanced mean SNRs due to the long-term fading effects produced by the movement of the user in the area served by the wireless network. The overall system performance is studied in Rayleigh fading channels. Closed-form expressions are derived for important system performance metrics, such as average end-to-end SNR, average error probability and outage probability. Furthermore, we investigate the CGR's average power consumption which in certain cases is lower compared to existed relays. Numerical results and simulations show an improvement in the end-to-end system performance.

Original languageEnglish
Title of host publicationChallenges in Ad Hoc Networking
Subtitle of host publicationFourth Annual Mediterranean Ad Hoc Networking Workshop, June 21-24, 2005, Ile de Porquerolles, France
EditorsK. Agha, I. Guerin Lassous, G. Pujolle
Number of pages10
Publication statusPublished - 2006

Publication series

NameIFIP International Federation for Information Processing
ISSN (Print)1571-5736


  • Average bit error probability (ABEP)
  • Combined gain relay (CGR)
  • Dual-hop transmissions
  • Outage probability
  • Rayleigh fading

ASJC Scopus subject areas

  • Information Systems and Management

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