Performance Analysis of Wireless OFDM System Using Raptor Codes with different Modulation

From last few decades, wireless communications industry is gaining momentum in both fixed and mobile applications. The continued increase in demand for all types of wireless services (voice, data, and multimedia) is fuelling the need for higher capacity and data rates not only in fixed but also in mobile applications. There are many techniques that fulfil these requirements. One of the most important techniques is Orthogonal Frequency Division Multiplexing (OFDM). In this paper, we analysis the performance of wireless OFDM system using Rapter codes. The time-varying features of wireless communication channels adversely affect the performance of the system. Raptor code is new emerging rate less code which has shown amazing performance over variety of channels. There is a constraint on the interleaving depth of OFDM-based system due to delay and maximum packet size. This non-ideal interleaving affects the maximum achievable diversity from the channel. We investigated the effect of correlation between fading blocks, which relates to the limited interleaving possible between carriers in an OFDM system, based on Raptor code. The simulation result based on different modulation technique using Raptor codes for BER calculation.