Cellular radiotelephone communication systems and methods downlink digital coded speech from a cellular radio exchange to a cellular radiotelephone bas e station and uplink downsampled (i.e. undersampled relative to the Nyquist ra te of two samples per symbol) radiotelephone signals from the cellular radiotelephone base station to the cellular radio exchange. The downsampled radiotelephone signals are demodulated at the cellular radio exchange and th e digital coded speech is modulated at the cellular radiotelephone base statio n. Diversity demodulation may be used at the cellular radio exchange, to diversity demodulate the downsampled radiotelephone signals at the cellular radio exchange. By downlinking digital coded speech from the cellular radio exchange to the cellular radiotelephone base station, and uplinking downsampled radiotelephone signals from the cellular radiotelephone base station to the cellular radio exchange, narrowband uplinks and downlinks may be provided between the base stations and the cellular radio exchange, to thereby reduce cost. Moreover, since demodulation takes place at the cellula r radio exchange rather than at the base stations, low cost base stations may be provided. However, since downsampled radiotelephone signals are transmitted from the base stations to thecellular radio exchange, diversity demodulation may be performed at the cellular radio exchange, to thereby improve the voic e quality of the cellular radiotelephone communications.
A MEDICAL MEASURING SYSTEM