Performance of a TDMA portable radio link with a switchingfrequency synthesizer

摘要

The authors present the performance of an experimental TDMA (timedivision multiple access) portable radio link with a switching singleloop frequency synthesizer. The synthesizer, used as a local oscillator(LO), operates around 2 GHz with a 400 kHz step size and can switch over20 MHz in less than 400 μs. Performance of the TDMA radio link usingWER (word error ratio) as a criterion was measured with the synthesizerswitching frequencies between bursts at the transmitter. WER versus SNR(signal-to-noise ratio) shows small degradation, only 0.5 dB at WER of10-3, due to the phase noise of the synthesizer signal. Thephase noise values for an offset of 10 kHz and 100 kHz were -70 dBc/Hzand -90 dBc/Hz, respectively. Measurements indicated that the radio linkperformance showed only minor degradation when the synthesizer wasswitched 20 MHz only 400 μs before transmitting a data burst. Thispermits a handset to switch to different channels than the channel ofoperation to measure signal quality for possible call-transfer onceevery 2 ms frame