Measurement of system performance of a SAW-based group demodulator and channel characteristics at Ka-band using Olympus

This paper describes measured Ka-band channel characteristics using the Olympus satellite and the correlation of system performance of a 64 kbit/sec FDMA/QPSK signal. The measurements were carried out with a ground terminal located in Ottawa, Canada. The elevation angle from Ottawa to Olympus was 14.2°. The measured channel characteristics are given in terms of signal envelope, signal phase and their probability distribution as well as a typical fading spectrum. The measured results are given for 10 representative weather conditions, ranging from clear sky to overcast and rain. The sample size of the analyzed data for each weather condition was one million values, representing a time duration of about 42 minutes. The results show that for the cases considered, the short term signal fading can be as small as 1.1 dB and as large as 9.7 dB for 99.5% of the time. In addition, during various weather conditions,the phase jitter can be as small as 6.4° and as large as 10.3°. Moreover, a maximum fade rate of 2.8 dB/sec was measured for the data analyzed. At the time of the channel measurements, the probability of bit error of a 64 kb/s FDMA/QPSK signal demodulated by a SAW-based group demodulator was also obtained. The measurements show that the degradation in terms of E_b/N_o ranges from zero to 3 dB or more depending on weather conditions