C/I balancing under limited power dynamics for JD-CDMA

In cellular mobile communications, to optimize spectrum efficiency of a cell net, carrier-to-interference-ratio (C/I) balancing by centralized power control (CPC) would be the optimum power control technique. CPC might be difficult to implement due to its heavy required signaling load. However, the study of CPC gives enlightening insight into the mechanism relevant to power control in mobile radio systems. CPC requires a large dynamic range of the transmission powers at the base stations (BSs), say of the order of 100 dB and sometimes more. This is practically not feasible, and hence there is a requirement for adequate power control techniques which work satisfactorily under the limited power constraint. The dynamic range of power typical for state-of-the-art transmitter amplifiers is very limited, for e.g., to a maximum of 20 dB as quoted by manufacturers and operators. In this paper, novel procedures for adjusting the transmitter powers under the consideration of limited dynamic range are envisaged to provide maximum possible C/I ratio at the receivers. Obviously, the C/I performance would degrade by a certain amount due to the limitation of the transmit power. The target system envisaged is the time divided-code division multiple access (TD-CDMA) system utilizing joint detection (JD). Monte Carlo simulations have been performed to evaluate the performance