In addition to frequency hopping and direct sequence, spread spectrum multiple access technique, there are some other hybrid combinations that provide advantages in the area of cellular mobile communication system. The available broadband spectrum is divided into a number of smaller bandwidth subspectrums. The frequency hopping multiple access technique (FHMAT) consists of a direct sequence modulated signal whose center frequency is periodically hopping in a pseudorandom manner. In this article we provide hybrid spread spectrum techniques using Time Division Code Division Multiple Access (TDCDMA) system where different spread codes are assigned to different cells within each cell, only one user per cell is assigned a particular time interval. The Time Division Frequency Hopping Multiple Access (TDFHMA) technique has an advantage in cases of severe multipath or when severe co-channel interference occurs. The subscriber may jump to the new frequency at the start of a new time division multiple access framework. These different areas covered by the antenna beam can be served by the same frequency or different frequencies. Keywords: frequency hopping multiple access, time division code division multiple access, time division frequency hopping, space division multiple access1 IntroductionSpread spectrum techniques spread information over a very particular area , a large bandwidth, a bandwidth much greater than the inverse of the data rate. In this paper, we will discuss various ways to provide multiple access by broadening the spectrum. Let's start with the conceptually simplest approach, Frequency Hopping (FH). We then proceed to the most popular form of spread spectrum, Direct Sequence-Code D...... half of the article...... Hybrid wireless networks using autonomous computing principles” IEEE, CNSR, 2005[4] C ., E. Masry, and L. B. Milstein, “Design and Analysis of a Fast Frequency Hopping DBPSK Communication System, Part I,” IEEE Trans. Communion, vol. COM-41, pp. 1552-1564, 1993[5] Masato Mizoguchi and Kazuhiko Seki, “Fast Frequency Hopping and Direct Sequence In-Chip CDMA Systems for Indoor Wireless Communications,” IEEE Trans. Commun, pp.1508-1512, 1996[6] Andreas F. Molsch, “Spread Spectrum Systems”, Wiley India Edition editor, pp. 469-471,2005.[7] Theodore S. Rappaport, “Multiple Access Technique for Wireless Communications,” Second Edition pp. 451-463, 1996.[8] Q. Chen, Q. Wang, and V. K. Bhargava, “Performance Error of SFHiDPSK Encoded in Tone Interference and AWGN,” IEEE Confrence Milcom, pp. 63-67, 1992.
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