Dimensioning of spread spectrum systems for ISDN

Abstract

In this communication we deal with wireless local loop (WJ.,L) systems using spread spectrum techniques to provide Integrated Services Digital Networks (ISDN) local access. We consider the dimensioning of a base station intended to serve various lSDN subscribers. The connection between subscribers and base station i s achieved via atmospheric channel and the transmission technique used is Direct Sequence Spread Spectrum - DS/SS). An expression that permits the calculation of a maximum number of users that a base station can serve in function of the desired qualicj of service (QoS) and mean traffic per user is derived. Based on this formulation we present numerical results, on the QoS for values of bit error probability required by ISDN and typical mean traffic of this kind of application.