PERFORMANCE ANALYSIS OF A SINGLE RELAY COOPERATIVE COMMUNICATION SYSTEM WITH DIFFERENT DIVERSITY PROTOCOL Md. Mahabub Hossain1*, Md. Dulal Haque1, Md. Mominul Islam2, Md. Raji All Noor Islam1 and Mohammad Minhazur Rahman1
Md. Mahabub Hossain, Md. Dulal Haque, Md. Mominul Islam, Md. Raji All Noor Islam and Mohammad Minhazur Rahman (2012). Performance Analysis of a Single Relay Cooperative Communication System with Different Diversity Protocol. Bangladesh Res. Pub. J. 7(4): 403-411. Retrieve from http://www.bdresearchpublications.com/admin/journal/upload/09362/09362.pdf
In this paper the performance of a cooperative communication system is analyzed under different diversity protocol. An enhanced four-node cooperative system, having a source, a destination and two serially arranged stations acting as relays is designed and analyzed while a threenode ad-hoc network with a single relay station has been considered as a reference model. Two retransmission protocols amplify and forward (AAF) and decode and forward (DAF) are implemented at the relays and four diversity combining techniques such as equal ratio combining (ERC),fixed ratio combining (FRC), signal to noise ratio combining (SNRC) and equal signal to noise ratio combining (ESNRC) are used at the destination for each protocol. The performance of single relay system is compared with the performance of direct transmission and transmission through single relay system. single-relay cooperative system offers better performance than that of direct transmission irrespective of the implementation of retransmission protocols and diversity combining techniques.
Key words: wireless networks, cooperative diversity, relay, diversity protocols, combining methods, fading, path loss.
During transmission over wireless channel the signal quality suffers severely from a bad channel quality due to effects like fading caused by multi-path propagation and path loss. To mitigate such effects diversity can be implemented to transmit or receive independent samples of the same signal along different propagation paths using multiple antennas. However, in some scenarios the wireless terminals may not be able to support multiple transmit antennas due to hardware limitations. In this case, diversity can also be realized by enabling single antenna mobiles in a multi-user environment to share their antennas and generate a virtual multiple-antenna transmitter that allows them to achieve transmit diversity. This is known as cooperative relaying. The relay virtually plays a role of another transmitter and helps the source to communicate with the destination. Since the information is transmitted through two independent wireless links, one is the direct link and another is the multi-hop link, a diversity gain is achieved
Department of Telecommunication and Electronic Engineering, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh. 2Department of Mathematics and Physics, Hajee Mohammad Danesh Science and Technology University, Dinajpur, Bangladesh. 1
In a cooperative system, selection of relays, processing and forwarding of the incoming signals by the relays, and selection of the path at destination with the best signal quality are some important issues. Selection of relays has been investigated for path loss channels from a minimum energy perspective by V. Rodoplu et al. (1999). A cooperative system is proposed by J. Boyer et al. where the intermediate relays combine, digitally decode and re-encode or simply combine and amplify the signals received from all preceding terminals Boyer et al., 2001. For one relay cooperative system, Amplify and Forward (AAF) and Decode and Forward (DAF) cooperative relaying protocols achieve full diversity (Nicholas Laneman, 2002). Moreover, Amplify and Forward...