Properties and capacity of a TDMA micro cellular office communication system

Properties of a time-division multiaccess (TDMA) microcellular cordless telephone system using dynamic channel allocation and hand-over are presented. The system has 16 time-division time-duplex channels (slots) per carrier, each occupying 2 MHz. The TDMA frame is 16 ms long and each slot has bits for synchronization, signalling, and data. The data speed is suited for 32 kb/s speech codecs. Procedures are developed for efficient and quick dynamic channel allocation and hand-over, using the fact that a single radio can simultaneously monitor or communicate on all 16 channels. Simulations for a specific six-storey building indicate that 16 channels can provide wireless communication for up to 30% of the telephone and 32 channels for up to 100% of the telephones. Slot synchronization between adjacent systems is desirable, but not necessary. A modest echo control is needed on the trunk level interface to the PABX or PSTN (public service telephone network), if two wire transmission is used. Tests show that no time-dispersion equalizers are needed and that antenna diversity is effective against fading dips and time dispersion.<
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