Data Rate Control in CDMA Networks in Wireless Communication System

Posted on 14th Oct 2024 01:03:25 AM APEE


Introduction

A very important consideration in data communications is how fast we can send data, in bits per second over a channel. Data rate depends on three factors: 1) the bandwidth available 2) the level of the signal we use 3) the quality of the channel (the level of noise). For a noiseless channel, the Nyquist bit rate is equal to the twice times of the product of the bandwidth & logarithm of bits. For a noisy channel, Shannon capacity, to determine the theoretical highest data rate is equal to the product of the bandwidth & logarithm of one plus signal to noise ratio. As the demand of for high speed data service increases in wireless cellular networks, it is very important to achieve high data rate capability. For high speed data service, not only is the data throughput important but the data transmission delay is also a very important factor in determining the service and the network quality. The research in the literature to be solved most of the optimum resource control problems for trying to achieve the maximum data throughput. However, these kind approaches may be inefficient in terms of transmission delay because they mainly focus on maximizing the mean data rate.  These control schemes may result in serious unevenness in the data rate according to the channel conditions and thus, bad channel conditions will cause a significant transmission delay because of a slow data rate. On the other hand, a constant rate scheme with power control can provide even service quality at all instances. However, such scheme are inefficient in terms of power consumption, because they rely totally on transmission power control to compensate channel degradation and result in an increase in the total required transmission power. This is an especially critical problem in power limited systems, such as satellite communication networks. Where, generally, the dynamic range of transmission power is highly restricted. Consequently, this causes a reduction in the data rate under the transmission power constraint. The relationship between the average delay and processing gain and searched for the optimum gain, i.e. the optimum data rate, in order to minimize the average delay. The propose project the optimum power and rate joint control scheme for uplink CDMA networks in order to achieve the minimum mean transmission time. The optimum solution for power and rate in the user domain in order to minimize transmission delay averaged over simultaneous users experiencing independent channel variations in CDMA downlinks. Another technique, the ratioed power and the control (RPRC) algorithm to satisfy the requirement of the both the data rate and the signal quality. Power control is an effective measure for reducing the co-channel interference several centralized and distributed power control algorithm has been proposed in literatures. 

In centralized power control, the network center computes the feasible power set that meets the SINR requirements for all users simultaneously. However, it requires measurements of all the link gains and communication overhead between network center and base stations and thus is difficult to realize in a large system. Distributed power control, on the other hand, uses only local information to iteratively adjust the transmitting power of each individual user. It is much more scalable than centralized power control. However, the speed for finding a feasible power set may be a great concern.

Objectives of the study

The objective of the proposed research project is to study the following parameters in CDMA network.

1) Signal to interference noise ratio, SINR.

2) Co-channel interference.

3) Quality of services (QoS) such as protection and priority.

4) Maximizing total throughput aggregated utility, user fairness and total user utility.

5) Packet error rate and the transmission delay as the function of power and rate.

Methodology

The proposed project will fully based on MATLAB simulation. In simulation study, as the DATA  RATE CONTROL in CDMA spread spectrum network by using ½ convolution code, 1/3 convolution code , cross-correlation, autocorrelation, modulation, demodulation, (Walsh functions, pilot code, block codes channel coding, turbo codes, etc).

Time frame

Approximately one year will be required for the whole research work.

1. Three months for proposal review.

2. Four months for analyzing and data rate control methods.

3. Three months for system performance evaluation and necessary changes.

4. Two months for dissertation writing.

Results

The outcome of the proposed work will be provided both hard and softcopy.

Contribution & Socio-Economic Conclusion

The research project will help to design a robust network in wireless data communication system. Data rate control proposed project tackle the resource management problem in the multi-rate CDMA networks. The CDMA network is the most credible to the subscribers in the world. The results of the proposed project would encourage the young IT professionals of Bangladesh / other countries to make any further study to meet up the demands in telecommunication sector in globalization perspective. The target of the current democratic government to make Digital Bangladesh in vision 2021 will help to implement.