Pre-equalization with subband channel loading: a technique to maximize throughput in uplink OFDM-CDMA systems

This letter focuses on maximization of achievable throughput for uplink orthogonal frequency-division multiplexing code-division multiple-access (OFDM-CDMA) systems. In particular, a new pre-equalization technique is presented where all users employ spreading both in frequency (on sub-bands of the available spectrum) and time; moreover, bit and power loading is used at the mobile terminals to accomplish throughput maximization. To avoid interference among users, the proposed loading algorithm inherently inverts the channel amplitude on the sub-carriers of each sub-band, while the phase is adjusted separately.