| 摘要 |
A technique for converting a non-sectorized cell to a sectorized cell having multiple sectors utilizing a single broadband processing unit. The spectrum of a given frequency band having a center frequency 'OMEGAo is divided into multiple bands (three, for example) having center frequencies 'OMEGAo, 'OMEGAo-alpha and 'OMEGAo+alpha. In the receive path, respective sub-bands are used to convey analog RF signals from a subscriber in respective sectors to an associated transceiver. Each of the transceivers includes a front end for receiving incoming RF signals and an analog-to-digital converter for converting the analog signal to a digital data stream. The digital data streams from transceivers are combined, i.e., processed by digitally adding, and supplied to a single channelizer which, in turn, supplies the data to a TDM bus for transmission to a PSTN network. In the reverse path from the PSTN network, TDM digital data signals emanating from a TDM bus are supplied to a combiner which feeds each of the respective transceivers which select the appropriate data from the combiner by digital filtering or processing. The transceivers convert the digital signal to analog form. After conversion, power amplifiers associated with the respective sectors effect emission of radiated power in the respective sectors. Advantageously, amplifiers in the sectorized improvement operate at lower power levels than the single high power amplifier of a non-sectorized cell, thereby providing substantial cost savings. More importantly, instead of deploying multiple broadband processing units the improved sectorized cell requires only a single broadband processing unit, thereby providing further economies. |
