Adaptive Channel Estimation using Least Mean Square (LMS) for Orthogonal Frequency Division Multiplexing (OFDM)

In growing technologies, the speed of communication in wireless medium and limited radio frequency (RF) had taken a primary demand for increasing the bandwidth efficient air schemes and power over systems. After the development of cellular telephone system in 1980s. To provide greater system for demand over voice services major evolution in telecommunication sector had come in 1990s. The development Internet Protocol (IP) infrastructure network throughout nation gave rise to third generation wireless voice, multimedia, data services they are namely Wideband CDMA and CDMA2000 and finally to increase its efficiency fourth, fifth generation are developed on demand. Orthogonal Frequency Division Multiplexing, commonly known as OFDM [16]. This OFDM technique of multi-carrier modulation where the data is modulated by the parallelly sub-carriers. These subcarriers are regularly spaced. The main function of sub-carriers is to maintain the minimum separation frequency that is required for maintaining orthogonality of the waveforms which are in time domain. The signal spectra and the sub-carriers will overlap in the frequencies. This overlapping of signal spectra and the sub-carrier gives rise to a waveform which uses available bandwidth efficiently.