Multiuser detection Techniques for Fourth and Fifth Generatin Mobile Communication System

Abstract

newline Multiple Access Techniques one of the most emerging, major method and process for newlineair interface that prevail in today s mobile communication generation. These techniques use newlinemultiplexing process to provide reliable and efficient communication among the numerous newlineusers over single channel in mobile communication systems offering faster approach, better newlinequality of service with improved services more importantly depleting the inter symbol, newlineinterference, multi access interference etc.,. Also develops higher efficient distinct access newlinemethods along multiple carrier with multicarrier modulation. These multiple access techniques newlineenables to simultaneous sharing of channel capacity, radio spectrum, bandwidth, timing etc. newlineassuring orthogonality with zero correlation among the users in channel reducing ISI, MAI newlinealong noise. newlineTDMA is one such multi access techniques that divides users efficiently in time slots newlineamong the users in channel, FDMA is also a multiple access technique that divides users newlineefficiently by assigning frequency bands in the channel. These two multiple access techniques newlineare narrow band fails their performance as increased number of users in the channel. Further newlinethird generation mobile communication system introduced CDMA-Code Division Multiple newlineAccess. CDMA was the most efficient method which used Pseudo noise sequence which newlineconverts data bits into wide band assuring orthogonality among the numerous users pertaining newlinein channel. But as the users increased in the channel, design complexity increased reducing the newlinesystem performance in the channel. Thus Multicarrier technique was included with CDMA for newlineenhancing the performance, efficiently bandwidth utilization and assuring orthogonality in the newlinechannel. But due to multicarrier modulation, at receiver end increased massive detection and newlineestimation process raised which failed to achieve desirable bit error performance as well newlineenforced delay in the process. Interference such as inter symbol interference, multi access newlineinterference among the users was a