Performance analysis of CFO mitigation algorithms in asynchronous Cooperative OFDM communication system

In this paper, we analyze the non-cooperative Orthogonal Frequency Division Multiplexing (OFDM) and Cooperative-OFDM communication system by comparing their performances. Carrier frequency offset (CFO) mitigation is critical for OFDM based co operative transmissions because even small CFO per transmitter may lead to severe performance loss, especially when the number of cooperative transmitters is large. Here, we showed that cyclic prefix (CP) can be exploited to mitigate or even remove completely the CFO. The mitigation performance increases along with the CP length. In particular, long CP with length proportional to N*I, where N is the Fast Fourier Transform (FFT) block length and I is the number of cooperative transmitters, can guarantee a complete CFO removal. While this comes with a reduction in bandwidth efficiency, the long CP in the proposed scheme is exploited to enhance transmission power efficiency in a way similar to spread-spectrum systems, and thus is different from conventional CP that degrades both bandwidth and power efficiency. Here we showed that how performance of mitigation algorithm vary with cyclic prefix length and performance evaluation in case of error up in the estimation of carrier frequency offset (CFO).Comparing the performance of this mitigation algorithm with Orthogonal Frequency Division Multiple Access (OFDMA) mitigation algorithm for different carrier frequency offset values.