The Role of VLSI in OFDM Transceivers

OFDM is a multi-carrier system where data bits are encoded to multiple sub-carriers, while being sent simultaneously. This results in the optimal usage of bandwidth. A set of orthogonal sub-carriers together forms an OFDM symbol. Each sub-carrier in an OFDM system is modulated in amplitude and phase by the data bits. The process of combining different sub-carriers to form a composite time-domain signal is achieved using Fast Fourier transform. In this paper we propose an idea for implementing complex multipliers and FFT computers using [bit serial approaches and distributed arithmetic concepts]. Usually multiplication is done by successive additions or by design of parallel multipliers. Instead we propose a [Bit Shift Accumulation] technique based on [Modified BOOTH'S Algorithm] to implement [Complex Multipliers]. By this way the [speed of multiplication] performed is increased and the [chip area consumed] is decreased which results in [low power consumption]. Fast Fourier transforms are taken using RADIX 4 butterfly using [our Complex multiplier] as and when the bit arrives thus increasing the speed of OFDM transceivers.