A quantized reliability-relay selection method for wireless cooperative communications

Author

Alexan, Wassim ; El Mahdy, Ahmed

Author_Institution

Fac. of Inf. Eng. & Technol., German Univ. in Cairo, Cairo, Egypt

fYear

2014

fDate

26-29 Aug. 2014

Firstpage

318

Lastpage

322

Abstract

In this paper, we propose a relay selection method for cooperative communication systems (CCS) employing the QPSK modulation scheme. The relay nodes forward their reliability to the destination node, utilizing a quantized reliability-relaying (QRR) scheme. The reliability is divided into five different levels by the relay nodes, according to the log-likelihood ratio (LLR) value of the received signal from the source node. Then, a suitable symbol is forwarded to the destination node if the relay node is set as active. A relay node is set as active if the reliability of the received signal is beyond a certain threshold. We provide analysis of the LLR for QPSK and carry out numerical simulations comparing the bit error rate (BER) of the QRR method against regular decode-and-forward (DF) and the best relay selection algorithms. A channel estimation algorithm is utilized to evaluate the performance of the system, as well as calculations of the normalized mean squared error (NMSE) of the channels. The special case of a system employing BPSK is also investigated.

Keywords

channel estimation; cooperative communication; error statistics; quadrature phase shift keying; relay networks (telecommunication); telecommunication network reliability; BER; BPSK; CCS; LLR value; NMSE; QPSK modulation scheme; QRR scheme; bit error rate; channel estimation algorithm; cooperative communication systems; decode-and-forward; destination node; log-likelihood ratio value; normalized mean squared error; quantized reliability-relaying scheme; received signal; relay nodes; reliability-relay selection method; source node; Bit error rate; Channel estimation; Cooperative communication; Phase shift keying; Relays; Reliability; Cooperative communication; decode-and-forward; diversity gain; relay; reliability;

fLanguage

English

Publisher

ieee

Conference_Titel

Wireless Communications Systems (ISWCS), 2014 11th International Symposium on

Conference_Location

Barcelona

Type

conf

DOI

10.1109/ISWCS.2014.6933369

Filename

6933369