Chaotic sequences for reduction of PAPR in OFDMA system

Abstract

In wireless communication, the physical layer should facilitate multiuser, multirate transmission to support large number of users and applications with diverse needs. In this work chaotic sequences generated using logistic map were used to achieve multiple data rate in Orthogonal Frequency Division Multiple Access (OFDMA) system. Performance was compared with that of Orthogonal Variable Spreading Factor (OVSF) code. Increase in Peak to average power ratio (PAPR) due to variable spreading could be reduced by spreading using chaotic sequences.The spreading sequences could be chosen irrespective of the data rates used. It was also observed that chaotic sequences gave constant PAPR values for different combinations of data rates. Bit error rate was found to be comparable with that for OVSF codes.

Chaotic Sequences Generated by Chaotic Quantification under Finite Precision

“…Chaos is a complicated phenomenon of nonlinear dynamic system with the properties of pseudorandom and high sensitivity to initial value [1], and it is widely used in communication, signal processing and so on [2][3][4][5][6][7]. But when applied to practical systems, chaos will be periodic after several iterations because of the finite precision of the hardware, which is called finite precision problem [8].…”