In this paper, the performance of a CDMA mobile radio system is analyzed under different traffic loads. The major influential parameters are identified and their effect on traffic capacity is analyzed using a simulation model. New results have been obtained by analyzing the sensitivity of Erlang capacity to a range of CDMA network parameters namely call quality, shadowing, distance exponent, voice activity, and processing gain. Comparison of the results indicate that the most influential parameter is call quality while shadowing followed by the processing gain have the least effect. It is noted that when the offered load is low for the system under study, a change of a few Erlang in the offered traffic has insignificant effect on the blocking probability. As the traffic increases, and the call quality drops below an adequate threshold, there is a sudden increase in the sensitivity of the blocking probability to traffic load.

A study is made of the problem of placing base stations to yield high capacity and efficiency in an in-building direct-sequence code-division multiple-access wireless communication system. A key requirement for solving this problem is a reliable but simple model of in-building propagation. A number of propagation models are considered as part of a system's performance analysis and are found to produce widely ranging levels of accuracy. Correlated shadowing is identified as being a 'key'in-building propagation characteristic that has the potential to strongly influence the system's performance. Propagation models that included correlated shadowing are shown to produce the most accurate estimates of outage probability when there are a number of interferers facing a user. Base station deployment is shown to be a dominant factor influencing the levels of correlated shadowing, and consequently, base station deployment is shown to have major implications on the system's performance. The system's performance for a variety of base station deployment strategies has been determined. The results indicate that there is a tradeoff between system simplicity and performance.

Empirical justifications for the lognormal, Rayleigh and Suzuki (1977) probability density functions in multipath fading channels are examined by quantifying the rates of convergence of the central limit theorem (CLT) for the addition and multiplication of random variables. The accuracy of modeling the distribution of rays which experience multiple reflections/diffractions between transmitter and receiver as lognormal is quantified. In addition, it is shown that the vector sum of lognormal rays, such as in a narrow-band signal envelope, may best be approximated as being either Rayleigh, lognormal or Suzuki distributed depending on the fading channel conditions. These conditions are defined statistically.

The design of tomorrow's mobile communications systems will require accurate mathematical tools for estimating the performance of potential system configurations. Ideally these tools will be easy to apply and be based upon parameters that can be estimated by a simple appraisal of the propagation environment. In this paper a general outage probability technique for considering the effect of noise and cochannel interference on reception reliability is presented. The technique is used to assess the compatibility and applicability of previously published techniques as that either treat noise as cochannel interference or consider a minimum detectable received signal threshold. A simple yet accurate threshold-based technique is described and used to predict bit error rates (BER) for a variety of conditions. Specifically, outage probability is used to accurately predict average BER.>

Mobile radio systems are usually designed on the basis of providing adequate reception quality to a specified area. The outage probability equations are used to determine the quality of radio reception when that quality is limited by a minimum required signal level, interference from a cochannel transmitter, and variability in the received signal levels. Considering Rayleigh fading and lognormal shadowing as joint causes of signal variation, average outage probability expressions are derived for mobile radio systems of a uniform nature. These expressions are used to investigate the influence of various system and propagation characteristics on reception quality.>