directsequencecodedivisionmultipleaccess (CDMA) with orthogonal codes is under consideration for use in indoor radio communications. Spread spectrum with its inherent resistance to multipath and orthogonal codes ...
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directsequencecodedivisionmultipleaccess (CDMA) with orthogonal codes is under consideration for use in indoor radio communications. Spread spectrum with its inherent resistance to multipath and orthogonal codes for increased bandwidth efficiency make this implementation attractive. This paper analyzes the performance of such a system using actual channel measurements rather than the usual assumption of a statistically modeled channel to determine performance. Measurements from five different locations are used with different coherent RAKE receiver structures. Performance is presented as average probability of error as a function of signal-to-noise ratio.< >
The performance and some of the implementation aspects of a practical mobile radio communications network employing direct-sequence code-division multiple access (DS-CDMA) are examined. The use of spread-spectrum tech...
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The performance and some of the implementation aspects of a practical mobile radio communications network employing direct-sequence code-division multiple access (DS-CDMA) are examined. The use of spread-spectrum techniques results in a wideband system, thus permitting the potential exploitation of multipath signal energy and permitting a means of reducing interference arising from other users of the spectrum. An analytical performance model is developed in order to assess the spectral efficiency of a DS-CDMA communications network. The computer model permits the performance evaluation of various path diversity schemes alongside numerous digital-modulation and error-correction coding techniques while operating in a mobile radio channel. In order to substantiate the results presented, novel power control and handoff protocols are also proposed in light of the assumptions made.< >
Summary form only given. An experiment designed to demonstrate the feasibility of overlaying a directsequencecodedivisionmultipleaccess (CDMA) personal communications network (PCN) on an existing set of narrowban...
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Summary form only given. An experiment designed to demonstrate the feasibility of overlaying a directsequencecodedivisionmultipleaccess (CDMA) personal communications network (PCN) on an existing set of narrowband microwave users is described. The frequency band 1850-1990 MHz was chosen for the experiment; this band will be divided into two 50 MHz subbands, one for the base-to-mobile link and the other for the mobile-to-base link (the remaining 40 MHz will be used for guard bands). The experiment has two phases associated with it. The initial phase corresponds to the test of a single cell. The goal of the initial phase is primarily to determine what limitations, if any, have to be placed upon the overlay system; once this has been established, a full scale field test is planned for spring 1991 in both Houston and Orlando where 20000 to 25000 users per city will be deployed.< >
Spread-spectrum and single-channel-per-carrier (SCPC) transmission techniques work well in very small aperture terminal (VSAT) networks for multiple-access purposes while allowing the Earth station antennas to remain ...
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Spread-spectrum and single-channel-per-carrier (SCPC) transmission techniques work well in very small aperture terminal (VSAT) networks for multiple-access purposes while allowing the Earth station antennas to remain small. direct-sequencecode-divisionmultiple-access (DS-CDMA) is the simplest spread-spectrum technique to use in a VSAT network since a frequency synthesizer is not required for each terminal. An examination is made of the DS-CDMA and SCPC Ku-band VSAT satellite systems for low-density (64-kb/s or less) communications. A method for improving the standard link analysis of DS-CDMA satellite-switched networks by including certain losses is developed. The performance of 50-channel full mesh and star network architectures is analyzed. The selection of operating conditions producing optimum performance is demonstrated.
Upper and lower bounds on the average probability of error of directsequence (DS) spread-spectrum communication systems operating in the presence of either multiple tone or multipleaccess interference are presented....
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Upper and lower bounds on the average probability of error of directsequence (DS) spread-spectrum communication systems operating in the presence of either multiple tone or multipleaccess interference are presented. The bounds are quite tight and can be used without the restriction that the peak level of the interference be less than the desired signal level. A simple method for evaluating approximations to the bounds for multipleaccess systems, in which the peak interference does indeed exceed the desired signal level, is presented as well. The tightness of both the bounds and the approximations are illustrated with numerical results.
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