To identify the optimal duplex mode and maximize the offered gain in the relay system, we compare the performances of half-duplex relay (HDR) and full-duplex relay (FDR). Finite-state Markov chain (FSMC) models are presented, showing the joint effects of finite-length queues and adaptive modulation (AM) under uncorrelated Rayleigh fading channels. Transmission efficiency, packet loss rate, and delay are derived and compared based on these models. According to our results, FDR is superior to HDR in the low-signal-to-noise ratio (SNR) region but loses its advantage as the SNR increases. When the size of the queue is large enough, FDR can be superior to HDR, even in the high-SNR region.
Bibliographical noteFunding Information:
Manuscript received September 20, 2010; revised August 6, 2011; accepted October 23, 2011. Date of publication December 5, 2011; date of current version February 21, 2012. This work was supported by the National Research Foundation of Korea grant funded by the Korea government under the Ministry of Education, Science, and Technology under Grant 2010-0018938. The review of this paper was coordinated by Prof. N. Arumugam.
All Science Journal Classification (ASJC) codes
- Automotive Engineering
- Aerospace Engineering
- Electrical and Electronic Engineering
- Applied Mathematics