Implementation of CDMA2000 system for UWA using SIMULINK

Abstract

Underwater communication finds applications in oceanographic data collection, pollution monitoring, offshore exploration, disaster prevention, assisted navigation, tactical surveillance, and mine reconnaissance. The enabling technology for these applications is acoustic wireless networking. A major challenge for the deployment of UW-ASNs is the development of a Multiple Access technique and modulation technique tailored for the underwater environment and this is what my thesis is all about.

The title of my thesis is “Implementation of CDMA2000 System for UWA communication using SIMULINK”. In this, designing of underwater system is done by using CDMA2000 technology for multiple access. The underwater CDMA2000 system is designed using MATLAB SIMULINK Tools. It consists of various sections which perform different functions. Firstly, on the transmitter side, there are two major blocks named encoder and transmitter block which include error correction, security and spreading techniques. Transmitted signal is affected by rayleigh fading channel and on the receiver end, there are again two major blocks receiver block and decoder. These blocks include delay compensation, channel compensation, Signal to noise ratio optimizing, despreading and error correction techniques. All these major blocks are subdivided into various functional blocks which perform these operations.

The aim of the thesis is to design a system which is capable of efficient transmission as underwater communication is effected by many factors. The main focus of this system is to estimate the delay in the channel and to apply proper channel estimation. For this, proper techniques are used in the design. Along with that CDMA2000 system itself provide many advantages like robustness to frequency-selective fading, compensates for the effect of multipath by exploiting Rake filters at the receiver, multiple access capability, protection against multipath interference, privacy, interference rejection. The performance of the system is evaluated by various calculations and comparisons. Major performance determining factors are bit error rate of Underwater CDMA2000 system after the receiver section as well of the complete system which comes out to be 0.0236 after receiver section on the receiver side and 0.002909 of complete system , checking the synchronization between the signal at transmitter and receiver side by making use of delay estimation technique and by comparing the signal at different level of implementation, verifying the effect of the channel on the signal after applying compensation techniques by comparing the signal without including channel in the system with the signal retrieved from the system after including channel and after applying channel compensation techniques and comparing the signals taken before and after channel compensation.