Multirate schemes for WH-spread-CI/MC-CDMA over corelated frequency selective channel

As multimedia applications gain significant importance in 4G communication, there is a need to design communication system to transmit different data rates with required QoS. Traditional spread multiple access system uses WH code that results in higher multiple access interference (MAI) due to loss in orthogonality over multipath channel. In this work, phase characteristics of carrier interferometry (CI) codes and spreading diversity of WH code are used to provide multiple data rate schemes for spread CI multicarrier code division multiple access (spread CI/MC-CDMA) system. Bit error rate (BER) performance is evaluated for under-load and full-load variable rate spread CI/MC-CDMA system over correlated multipath fading channel at different system loads. The effect of phase jitters due to local oscillator imperfection on multiple rate communication has been analyzed and verified through simulations.