Performance Evaluation of Rake and Pre-Rake Receiver for a Wireless DS- CDMA System

A new method to deal with multi path fading environment for DS–CDMA wireless networks has been proposed. Here, depending upon the statistical nature of the channel, signal is transmitted as a sum of various spreaded signals; each one delayed and scaled according to the delay & strengths of the multi paths of the transmitted channel. New method known as Pre-Raking is performed at the transmitted side rather than the conventional rake method performed at receiver side taking considerations of BPSK modulation scheme. This makes an easier design to the portable mobile sets. Simulated analyses for both the processes have been done for orthogonal and random codes using Monte-Carlo method. Results show that both methods give nearly equal performance for orthogonal codes whereas Pre-raking over-performed raking for random codes.