Performance Analysis of MC-CDMA Sytems Using Chaotic and Conventional Spreading Sequences
Henrieta Palubová, Pavol Galajda · Acta Electrotechnica et Informatica · 2011
Performance evaluation and comparison of multi-carrier code division multiple access (MC -CDMA) system model for usually used spreading sequences (Golay, Zadof-Chu, Gold) with chaotic sequences (generated by improved logistic map, by chaotic map with different slopes and by tent function) at the presence of Saleh and Rapp model of high power amplifier (HPA) is investigated.Rayleigh channel model and AWGN channel model is used in this simulation.Nonlinear amplification of HPA introduces degradation of bit error performance and destroys the orthogonality among subcarriers.In order to avoid performance degradation without requiring extremely large backoffs in the transmitter amplifier, it becomes convenient to use nonlinear multi-user detection techniques at the receiver side for all spreading sequences.To illustrate this fact, microstatistic multi-user receiver (MSF-MUD) and conventional minimum mean square error receiver (MMSE-MUD) are considered and mutually compared.The results of analyses are based on computer simulations.The best performance for Rayleigh channel model we can obtain when we used the Golay or Chaotic sequences in combination with MSF-MUD or MMSE-MUD, with using 8 -PSK modulation type.