A near optimal subchannel allocation policy in forward links for multicarrier CDMA system

In this paper a new model of a multicarrier (MC) CDMA system is proposed with forward links transmission for a cellular network. In the proposed system, the user estimates all subchannels' fading amplitude and feeds back all indices of its interested subchannels where the fading amplitudes are higher than a pre-fixed threshold to the basestation to guarantee the quality of service. With the indices information, the basestation transmits each user's direct-sequence (DS) waveform over one of its interested subchannels. Based on the criterion of maximizing the total average signal to interference plus noise ratio (SINR), a near optimal subchannel allocation policy is proposed and one iterative algorithm for its implementation is obtained. Simulation results show that the average performance in the proposed system can be improved compared with that only using the favorite subchannel for each user in Kim et al. (1999) when random signature sequences are used.