Applications of Walsh Functions and the FHT in CDMA Technology
A unified approach for modulation and demodulation of CDMA signaling based on IS-95 standard  is proposed. We propose a simpler forward link design, based on Fast Hadamard Transform (FHT) for generating the composite signal. In some systems, available power is a scarce resource and some power saving can be obtained when the user terminal is able to derive its phase, time and frequency references without the aid of a pilot signal. This necessitates some form of suppressed carrier tracking. A modified receiver using the FHT technique is proposed to implement phase, frequency and time tracking at the user terminal.
KeywordsCorn Cross Correlation Cose
Unable to display preview. Download preview PDF.
- TIA/EIA/IS-95 Interim Standard, Mobile Station-Base Station Compatibility Standard for Dual-Mode Wideband Spread Spectrum Cellular System, Telecommunication Industry Association, July 1993.Google Scholar
- A. Lempel, “Hadamard and M-Sequence transform are permutationally similar,” Applied Optics, vol. 18, No. 24, 15 Dec. 1979.Google Scholar
- A. J. Viterbi, Principles of Coherent Communication, New York: McGraw-Hill, 1966Google Scholar
- W.C. Lindsey and M.K Simon, Telecommunication Systems Engineering, New York, Dover Publications, 1973.Google Scholar
- R. L. Bogusch, Digital Communications in Fading Channels: Tracking and Synchronization, ReportWL-TR-90-15 of Mission Research Corporation sponsored by Weapons Laboratory, Kirtland AFB, NM, April 1990.Google Scholar