Low-complexity quantize-and-forward cooperative communication using two-way relaying

Cooperative communication is used as an effective measure against fading in wireless communication systems. In a classical one-way cooperative system, the relay needs as many orthogonal channels as the number of terminal it assists, yielding a poor spectral efficiency. Efficiency is improved in two-way relaying systems, where a relay simultaneously assists two terminals using only one timeslot. In the current contribution, a two-way quantize-and-forward (QF) protocol is presented. Because of the coarse quantization, the proposed protocol has a low complexity at the relay and can be used with half-duplex devices, making it very suitable for low-complexity applications like sensor networks. Additionally, channel parameter estimation is discussed. By estimating all channel parameters at the destination terminals, relay complexity is kept low. Using Monte Carlo simulations, it is shown that the proposed QF protocol achieves a good frame error rate (FER) performance as compared to two-way amplify-and-forward (AF) and one-way relaying systems. It is further shown that, using the proposed estimation algorithm, the FER degradation arising from the channel parameter estimation is negligible when compared to an (unrealistic) system in which all parameters are assumed to be known

PERFORMANCE ENHANCEMENT OF WIRELESS NETWORKS USING COOPERATIVE DIVERSITY TECHNIQUES

Channel weakening is one among the significant issues in wireless communication which can be overcome by the exploiting diversity gain, achieved via cooperation between nodes and relays. In order to improve the gain, generally, we require more than one transmitting antenna in a node, which is not too common due to the limits in size and complexity of wireless mobile devices. Anyway by offering reception apparatuses to other single-receiving wire hubs in a multi-client condition i.e., agreeable decent variety, a virtual multi-radio wire cluster is framed and transmit-assorted variety is cultivated. In our proposed work, a network containing a sender, a destination and a fixed relay, is analyzed with  modified  cooperative diversity scheme  such as Amplify-Quantize and Forward (AFQ) and compared with existing cooperative communication  protocol i.e.,  Amplify and forward (AF). Moreover the performance of the proposed work is evaluated in terms of Bit-Error Rate, SNR and Outage Probabilit