To Study the Power and Data Rate Control in CDMA Networks in Wireless Communication System

In this work, we have studied the data rate control in CDMA networks using the rationed power and rate control (RPRC) algorithm. In CDMA wireless networks, all users share the same frequency band and thus the co channel interference is even larger than that in other access schemes. The power control is an effective measure for reducing the co channel interference and increasing the data rate for sustaining satisfactory reception. There are two forms of the RPRC algorithm. These are: (i) The bandwidth allocation (RPRC-BA) algorithm and (ii) The achieving individual required rate (RPRC-AIRR) algorithm. We have worked taking the RPRC-AIRR algorithm to attain our desired goal. By using this algorithm, we have found out the available rate and the update power of the representative user. This algorithm works on the principle that as follows: There are two types of users one is called representative user and other is called non-representative user. In a cellular system there are numbers of cells, the representative user adjusts its power level according to certain distributed power control algorithm. This has been done by using the distributed constrained power control (DCPC) algorithm.

 The ratio of the power level for the non-representative user to the representative user is kept constant. At end of the certain numbers update operations the power levels for all users become constant and the available rate is the transmission rate that makes the received SINR equal to the SINR requirement. The system parameters are derived from those used in a CDMA system reverse link (data transmits from mobile set to base station) transmission at random position in a cell in CDMA system.  The received power level of the representative user has been updated by using Distributed constrained power control (DCPC) Algorithm. We have considered fifty (50) users for analyzing the available rate by using the RPRC-AIRR algorithm. The locations of the users are uniformly distributed within a cell area. The radius of the cell is 1Km and a base station is located in the middle of each cell. The required SINR is less than or equal to 4dB, the maximum power level is set to 1w and, the spread bandwidth is set to 1.25 MHz.

The ability to communicate with people on the move has involved remarkably since Guglielmo Marconi first demonstrated radio’s ability to provide continuous contact with ships sailing the English Channel. Code division multiple access (CDMA) is a wireless communications standard well accepted by industry today. Much research has gone into optimizing the system for voice and data applications. So the demand of data rate control in CDMA network is increasing day by day. There are many works about data rate control has been done before. In discuss the admission control for maximizing the throughput in CDMA systems. Furthermore, joint rate and power control has recently attracted much attention from researchers. In the proposed the distributed strategies for the joint control of power and data rates in a wireless network by takin into account the congestion levels as well. 

They initially assume that each node in the network employs a flow-rate control algorithm, and then they assume that each node in the network adjusts its power according to the power control algorithm. The objective is to design the power sequence such that the desired SINR level can be achieved. In describe the algorithm for controlling mobiles’ transmitter power levels while explicitly handling their time-varying transmission rate. During the whole power control process, the required signal quality is always maintained. In the integrated power and rate control (IPRC) for data applications over CDMA wireless networks. The IPRC algorithm needs to measure the received SINR and adjust the power levels for all users. In describe the combined rate and power adaptation schemes where the transmission power and the data rate are adapted relative to channel variations. 

The proposed schemes of authors can reduce the average transmission power, while maintaining the same average data rate and bit error rate. In the optimum uplink power/ rate control for minimum delay in CDMA networks. The proposed scheme efficiently allocates the power and rate in order to adapt slow variation for a given mean transmission power. A combined power and rate adaptation scheme has been proposed for direct-sequence code division multiple-access (DS/CDMA) systems over the Rayleigh-fading channels in and over the Nakagami-fading channels.  The power and rate adaptation algorithms to optimize the system performance based on the received SIR. The aim of this study is to contribute to this important research area by studying existing combined power and rate control (RPRC-AIRR) algorithm for analyzing available rate and power in a cellular CDMA network, identifying several important problems and have tried to solve them and provided the solutions to the problems.


Jagadish Chandra Roy
teaches computer science
in PTI, Nilphamari.