A Novel Approach for Frequency Hopping Cdma Technique

Frequency-Hopping Spread Spectrum (FHSS) is a method of transmitting radio signals by rapidly switching a carrier among many frequency channels, using a pseudorandom sequence known to both transmitter and receiver. It is utilized as a multiple access method in the frequency-hopping code division multiple access (FH-CDMA) scheme. A frequency-hopped spread spectrum multi-access network which is subject to the threat of multipath interference. The quality of a signal is affected by the channel noise, multiuser interference, and multipath interference. In this paper, we propose a “two-level” frequency hopping code-division multiple-access (FH-CDMA) scheme for wireless communication systems. This scheme provides flexibility in the selection of modulation codes and FH patterns. By partitioning the modulation codes, our two-level scheme can be modified to support more possible users without increasing the number of FH patterns. The performance and spectral efficiency (SE) of the scheme are analyzed. Our results show that the partitioned two-level FHCDMA scheme supports higher data rate and greater SE than the existing methods.