Adaptive Equalization of Fast-Time Varying Channel for EDGE System Enhanced by Dual Symbol Rate

Abstract

Our modern society has transformed to an information-demanding system, seeking voice, video, and data in quantities with high mobility that could not be imagined even a decade ago. High data rate high mobility creates challenges to the communication system. The challenge to the system is to conceive highly reliable system unaffected by the problems caused in the multipath fading wireless channels. Broadband single carrier modulated signals experience severe multipath distortion scrambling & ISI when propagating through physical medium. To mitigate the effect of channel a transmission burst includes a training sequence which is known to the receiver and depending upon the effect of the channel in the received training sequence the equalizer updated. In mobile communication due to the relative motion between the mobile equipment and network element the channel experienced is time varying. The properties of the equalizer used for tracking such time varying channel have to be time varying hence adaptive. This thesis focuses on fast time varying channel where each radio burst experiences varying channel response. However for fast fading channel where each radio burst experiences varying channel response a single training block in a radio burst may not be sufficient to track the channel. In this thesis two training sequence are used in a single burst of a DSR EDGE. A slight modification is done in the burst structure to include two training sequence keeping the number of symbol in a frame constant. A least mean square error based algorithm is used for equalization of fast time-varying channel. The simulation of the system was done in Simulink. The simulation of the communication system showed the equalization and estimation of the symbols using two training sequence has better performance than that with single training sequence used in DSR EDGE frame.