Joint adaptive power and modulation management in wireless networks with antenna diversity

In multi-access wireless communication systems, power control and adaptive modulation are two important means to increase spectral efficiency, combat the time varying fading environment, and reduce cochannel interference. The overall uplink transmitting power is optimized while the overall network throughput is fixed. Each link can select a range of targeted signal-to-interference-plus-noise ratio (SINR) according to its current channel condition and each link\´s time average SINR is maintained as a constant to ensure fairness. Adaptive M-QAM or M-PSK modulation with antenna diversity is applied to increase spectral efficiency. The scheme can be interpreted as "water filling" each link\´s SINR in the time domain and allocating network throughput to different links at each time. From simulation results, our scheme reduces about 40% of overall transmitting power and increases average spectral efficiency by about 0.9 bit/s/Hz.