CDMA

the title of the project is? *DS-CDMA with variable code length. Simulation of,performance inAWGN channel**.**the key words are? * DS-CDMA, Spread spectrum, processing gain, wideband The task is to simulate the de-spreading of a CDMA sequence in the presence of AGWN, and to investigate how, by increasing the code length, it is possible for the system to operate in larger and larger noise [login to view URL] is to be done using MATLAB programming . ## Deliverables ***DS-CDMA with variable code length. Simulation of,performance inAWGN** **channel.*** **Key concepts & Keywords:** DS-CDMA, Spread spectrum, processing gain, wideband **Overall task** The task is to simulate the de-spreading of a CDMA sequence in the presence of AGWN, and to investigate how, by increasing the code length, it is possible for the system to operate in larger and larger noise levels. **Revise the following:** **1 Review principles of DS-CDMA** ( direct sequence - code division multiple access), *e.g.? * chapter 2 of [1]. **Keywords:** pseudo-noise (PN) codes, autocorrelation, cross-correlation **2 Review properties of AWGN** ( additive white Gaussian noise) [2]. Auto correlation, Gaussian. **Keywords:** Random signals, time domain,& frequency domain properties of noise, white noise, bandlimited noise. **Goal here:** Find out how to generate (simulate) noise. **Simulation** Begin by simulating DS-CDMA de-spreading the absence of noise. Begin with short sequence ( *e.g.* 4 -bit) pseudo-noise (PN) codes. Recall synchronisation & de-spreading can be achieved by multiplying the desired DS-CDMA with the timeshifted versions on the incoming sequences ( made up of bits from many DS-CDMA signals) and integrating to find the auto-correlation peak. Add noise onto the incoming signals, and examine the effect on performance. Increase noise level. Increase code length ( *i. e.* find new longer PN codes) *i need a program using matlab which generates the wave forms as in fig 2.12 shown in the attachment? below. * **References** [1] *]* Bannister *et al,? Convergence Technologies for 3G Networks,* Wiley 2004. *••••* [2] Taub & Schilling, *Principles of Cummunications Systems,* McGraw Hill 1986