Performance enhancement of mimo mobile ad hoc networks for IEEE 802 16 wimax system deploying cross layer design

Abstract

Emerging wireless Ad hoc networks demand for wide range of applications such as multimedia streaming, voice-over-IP (Vo-IP), video conferencing and web browsing. One of the major goals of next generation mobile Ad hoc networks is to support high data rate multimedia traffic having diverse quality of service (QoS) requirements, such as, delay, bit error rate, throughput and packet dropping rate at moderate costs anywhere and at anytime to the mobile users. In order to meet these requirements over the fading channels call for innovative techniques. This has motivated the researchers to develop of efficient transmission techniques. This thesis aims at developing efficient performance enhancement techniques while satisfying the stringent QoS requirements of the emerging wireless systems. In order to improve the system performance accurate channel state information (CSI) is required at the transmitter and/or the receiver. However in practical wireless systems the channel state information may be imperfect due to estimation error, noise and feedback delay. For analyzing the imperfect CSI a variable power adaptive cross layer MIMO OFDM system has been developed. The proposed system can provide additional spectral efficiency gain while guaranteeing the delay compared to the constant power MIMO OFDM system for the same average SNR thus supports real time multimedia traffic. C o o p erative communications realizes the performance of MIMO systems through multiple relays. The performance can be further improved by properly selecting the relays for transmission. An adaptive relay selection algorithm has been proposed for amplify and forward based cooperative diversity system. The proposed algorithm provides higher capacity gain than the conventional scheme. In summary, this research work reports the cross layer design, performance analysis and simulation of various performance enhancement techniques for emerging wireless applications. newline newline newline