Performance of a TDMA portable radio link with a switching frequency synthesizer

Abstract

This paper presents the performance of an experimental TDMA portable radio link with a switching single loop frequency synthesizer. The synthesizer, used as a Local Oscillator (LO), operates around 2 GHz with a 400 KHz step size and can switch over 20 MHz in less than 400 psec. Performance of the TDMA radio link using WER (Word Error Ratio) as a criterion was measured with the synthesizer switching frequencies between bursts at the transmitter. WER versus SNR (Signal-to-Noise Ratio) shows small degradation, only 0.5 dB at WER of due to the phase noise of the synthesizer signal. The phase noise for an offset of 10 KHz and 100 KHz were -70 dBc/Hz and -90 dBc/Hz, respectively.Measurements indicated that the radio link performance showed only minor degradation when the synthesizer is switched 20 MHz only 400 psec before transmitting a data burst. This permits a handset to switch to different channels than the channel of operation to measure signal quality for possible call-transfer once every 2 msec frame.