Throughput enhancement using network modulation in cooperative communication

Cooperative communication has been widely investigated to improve the system coverage and efficiency of wireless communication. Cooperative communication enables efficient utilization of communication resources, by allowing nodes or terminals in a communication network to collaborate with each other for information transmission. In conventional data transmission, all bits in a symbol are treated in similar manner, having same bit error rate (BER) performance. In order to provide differential services at physical layer, the bits in a symbol can be divided into layers using Scalable Modulation. Network Modulation (NM) is a software based approach to rearrange the constellation of conventional quadrature amplitude modulation (QAM) so that a single symbol may contain different data for different users. In this paper, NM approach has been analysed in a three node scenario and new NM constellations are proposed. BER performance of proposed NM schemes is evaluated through simulations. Simulation results show that throughput can be enhanced by using these new NM schemes.