Int. J. Advanced Networking and Applications Volume: 05 Issue: 01 Pages:1818-1824 (2013) ISSN : 0975-0290 1818 Performance Evaluation of Fractionally spaced constant modulus algorithm (FS- CMA) in Relation to CMA (Constant modulus algorithm) method for blind equalization of wireless signals Dr. JKR Sastry drsastry@kluniversity.in KL University, Vaddeswaram, Guntur District Mr. T Rambabu Rambabo.thadisetty@gmail.com Andhra University, Visakhapatnam Dr. P Rajesh Kumar rajeshauce@gmail.com Andhra University, Visakhapatnam -------------------------------------------------------------------ABSTRACT--------------------------------------------------------------- --- Wireless communication is being used for many purposes and has become very frequently used mode of communication. Blind equalization methods are being used to estimate the received signal without the necessity to use the trained sequences in the input. Many methods CMA (Constant Modulus Algorithm), FS-CMA (Fractionally spaced CMA), PC-CMA(Phase compensation CMA), MMA(Multi-Modulus Algorithms) are being used for blind equalization. However all the methods are affected due to Inter symbol interference (ISI) and Bit error rate(BER) in the transmission.It has been proved [9] that CMA performs reasonably well compared to LMS methods in the absence of trained sequences. However the method suffers from issues such as Partial spacing, non-phase compensation etc. In this paper the performance evaluation of FS-CMA in comparison to CMA considering the model parameters at which the maximum performance can be achieved is presented. The performance of FS-CMA as against CMA in respect toInter Symbol interference ISI[1] and Bit error rate (BER), considering optimum parameters has also been presentedin this paper. Key words:FS-CMA, CMA, ISI, BER, Blind equalization, wireless communication, Model parameter, optimum model parameters -------------------------------------------------------------------------------------------------------------------------------------------------- Date of Submission: 28 th Jul 2013 Date of Acceptance: August 23, 2013 -------------------------------------------------------------------------------------------------------------------------------------------------- I. Introduction Wireless communication is being used for many purposes and has become very frequently used mode of communication. But the wireless communication gets affected due to various types of noises that include multipath effect, inter symbol interference, inter carrier interference, co-channel interference, ambiguity in transmission of bits etc. The noises limits channel bandwidth and time varying multipath propagation [4]. The method of receiving data without prior knowledge of transmitting information is called as blind equalization. Many types of filters and algorithms are in use to affect blind equalization. CMA (Constant modulus algorithm) [2, 3] is most frequently used algorithm for affecting blind equalization which has many limitations such as lack of phase compensation, fractional spaced diagonal compensation etc. Fractional-Spaced Constant Modulus Algorithm (FS- CMA) [5] is an improved algorithm over CMA algorithm [2,3]. CMA does not compensate for phase losses. The Fractional Spaced Equalizer (FSE) [6, 7] is the parallel combination of a number of Baud Spaced Equalizers (BSE). The baud space is known as fraction of time space. The sampling factor determines tap spacing of the FSE.