Analysis of Link Adaptation Algorithms Using Coding Scheme for OFDM Systems Under Frequency Selective Fading Environment

Orthogonal frequency division multiplexing (OFDM) is a robust technique utilized in wireless communication systems affected by frequency selectivity. In combination with multiple antennas at the transmitter and receiver as well as adaptive loading algorithms, OFDM proves to be robust against frequency selectivity. This paper presents OFDM with link adaptation algorithms applied to Multi-Input Multi-output (MIMO) systems. In this paper we apply an optimization discrete bit loading algorithm and power allocation for each subcarrier assuming instantaneous channel state information is known at both the transmitter and receiver. To improve the BER performance of wireless systems, coding techniques such as gray code and trellis coded modulation (TCM) are employed at the transmitter.