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Future third generation cellular systems (UMTS in Europe, IMT-2000 for ITU) will offer an increased range of services, and thus should accommodate much higher service bit rate than second generation. Unless the use of these new services is limited to very restricted area, like indoor office buildings, simple considerations on link budget and on spectral efficiency show that the use of smart antennas is mandatory in order to actually offer these high rates. This paper evaluates the capacity improvement of base station sites, allowed when using adaptive antennas (AA). It takes into account various errors that cannot be avoided from a practical point of view, like imperfect path loss evaluation and power control, or imperfect estimates of mobiles location. It concludes that the expected degradation is reasonable, and should not compromise the AA benefits. |
