Pacific Telesis Group Inc, the San Francisco-based Baby Bell, says that its Telesis Technologies Laboratory is now conducting a full-service personal communications services field trial that it hopes will demonstrate that shared spectrum operations can take place in the 1.85GHz to 1.99GHZ band with existing microwave users in downtown San Francisco: the field trial features a Nokia Cellular Systems Corp DCS 1900 system that uses narrow band, low-power Time Division Multiple Access-Frequency Division Duplex radio technology with 13Kbps digitised speech to minimise spectrum use; the company says that frequency agile equipment provides mobility management at vehicular speeds, while the open Nokia architecture uses Signalling System 7 technology and incorporates Smart Cards for identification, billing and other digital services; the Mobile Switching Centre, Home Location Register, Authentication Centre and Base Station Controller will be installed in the Telesis Technologies building in Walnut Creek – with three test base stations in San Francisco, and two in Walnut Creek; the company is also conducting an in-building trial aimed at Centrex and PABX users to test both high rise and campus applications.
