International Journal of Mathematics And Computer Research

Abstract

In this project, we propose a “two-level” frequencyhopping code-division multiple-access (FH-CDMA) scheme for wireless communication systems. In our two-level FH-CDMA scheme, the available transmission bandwidth is divided into ℎ frequency bands with . carrier frequencies in each band. In the first (modulation) level, a number of serial data bits is grouped together and represented by a symbol. Each symbol is, in turn, represented by a modulation code of dimension × . In the second (FH) level, each user is assigned a unique FH pattern of dimension ℎ × ℎ and weight (i.e., number of elements) ℎ, where ℎ is the number of frequencies, ℎ is the number of time slots (i.e., pattern length). The elements in the modulation codes and FH patterns determine the carrier frequencies of the final FHCDMA signals. . The new scheme provides flexibility in the selection of modulation codes and FH patterns. Our results show that the partitioned two-level FH-CDMA scheme supports higher data rate and greater SE than Goodman’s frequency-shift-keying FHCDMA scheme