Simultaneous rate and power control in multirate multimedia CDMA systems

Abstract

We consider a wireless multimedia CDMA system, where the different mobiles transmit at different rates. We devise a method of simultaneously optimizing the power and rate at which the different terminals transmit for achieving their required Quality of Service (QoS). The QoS is defined to be the effective data rate which is different from the transmission rate. Optimization of power enhances battery life and optimization of data transmission rates facilitates in building cheaper and power efficient mobile systems. The joint optimization problem is formulated so that for a specified Q o S , the total power transmitted by all the mobiles, and the sum of the transmitting rates of different mobiles can be minimized. The optimization problem is shown to be a non-linear and non-convex problem, but is solved to get a globally optimal solution using geometric programming. Results show that with optimized rates and powers, we can obtain better QoS than that obtained by present systems which use higher power.

A More Realistic Approach to Information-Theoretic Sum Capacity of Reverse Link CDMA Systems in a Single Cell

“…These works assume multi-user detection techniques and focus on the set of all capacities. Whereas, more recent works analyze the aggregate reverse link capacity, using matched filters [5][6][7].…”

“…Capacity of a single point-to-point communication link is well approximated by the Shannon theorem as C = B log 2 1 + S N [4] (Also, see [5]). Here, B is the bandwidth and S N is the signal to noise ratio of the communication link.…”

Cross Layer Optimization Based on Rate Distribution in Multirate Wireless Sensor Network

“…Many research activities related to multi rate and power control are reported in the CDMA areas [16,17] . However, their primary goal is to maximize channel utilization [18,19] and minimize the interference and near-far effect [20,21] . As a result, the multi rate and power control schemes in these works are not suitable for WSN.…”

Asymptotically optimal transmission power and rate control for CDMA channels with MF and MMSE receivers

“…System where the instantaneous transmission rate is adapted to channel gain variations as fast as the transmission power, referred to as fast-rate-fast-power control systems, have been studied in [6,7,10] for a DS-CDMA channel with a conventional MF and random spreading codes. Note that if the instantaneous transmission powers and rates are both functions of the instantaneous channel gains and there is no a priori classification into user classes, then the combined power and rate control collapses to the classical power control problem [27].…”

“…For instance, the DS-CDMA channel capacity with a conventional MF detector is lower than that of a channel with a linear MMSE multiuser detector [25]. The studies [6,7,[9][10][11]19] have considered rate control problems for a channel with a conventional MF detector. This paper explores a DS-CDMA channel with both receiver types, the linear MMSE multiuser detector and the conventional MF receiver, and demonstrates a clear and significant difference between the two.…”