Recently, exponential rise in the demand of wireless communication has led to gross reduction availability frequency spectrum meet proliferation demands. Overlay and underlay cognitive radio used address this problem is characterized with poor management assigned spectrum. The basic essential mechanism Radio (CR) find unused called Spectrum Sensing. This important optimizing allocation for incr...

OFDM, MC-CDMA and DS-CDMA are being researched vigorously as the prospective signaling technique for the next generation mobile communications systems, which will be characterized by the broadband packet technology. With packet transmissions, hybrid ARQ (HARQ) will be inevitable for error control. HARQ with rate compatible punctured turbo (RCPT) codes is one of the promising techniques. Data ra...

In this paper, new direct constructions of Z-complementary code sets (ZCCSs) from generalized Boolean functions are proposed. the literature, most ZCCS based on lead to sequences power-of-two length. study, we show that our proposed methods result in ZCCSs both length and non-power-of-two Since monomials degrees more than 2 employed constructions, can be obtained. The constructed admit theoreti...

Quasi-complementary sequence sets (QCSSs) play an important role in multi-carrier code-division multiple-access (MC-CDMA) systems. They can support more users than perfect complementary MC-CDMA It is desirable to design QCSSs with good parameters that are a trade-off of large set size, small periodic maximum magnitude correlation and alphabet size. The main results construct new infinite famili...

In this paper, based on the concept of Code Division Multiple Access (CDMA), we propose an innovative secret message multiplexing scheme by digital image data hiding. messages distributed for several participants are encoded into a CDMA codeword through and then embedded grayscale image. At receiving side, each intended recipient will be assigned distinct spreading code as key extraction. way, ...

In this paper, we propose a new fast-frequencyhopping code-division multiple-access (FH-CDMA) scheme for wireless communication systems, in which Reed-Solomon (RS) codes are modulated on top of FH-CDMA for supporting higher data rate than conventional M -ary frequency-shiftkeying FH-CDMA (MFSK/FH-CDMA) scheme and our recently proposed prime/FH-CDMA scheme. The performance of the RS/FH-CDMA sche...