Mobile Radio Transmission System -4.Multi-Station Simultaneous Transmission

If a wide service area is covered by a few base stations, the average radio wave reception level is minimum at the points lying midway between the base stations. To secure reliable communications throughout the service area, we can use the transmission diversity technology called route or site diversity; adjacent stations transmit the same signal to the same mobile unit. This can also allow the transmission power to be reduced.

Since it is difficult for each base station to exactly match frequencies with each other in the case of multi-station simultaneous transmissions, a gap can occur in carrier wave frequencies that leads to a deterioration in transmission quality. This problem is overcome by offset transmission methods such as frequency offset and waveform offset. In the case of frequency offset, the frequency of the carrier wave is offset by a certain value, which improves the signal error rate. In waveform offset, frequency modulation is used to improve the signal error rate by superimposing the sine waves of different phases on the base band signals.


Simultaneous Transmission from Multiple Base Stations in Paging Systems

noticeCreated 1999/03

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