Experimental evaluation of packet error rates for the 850 MHz mobile channel

A series of field measurements were conducted to examine the transmission characteristics of different digital land mobile systems in the VHF/UHF frequency bands. This paper briefly describes these measurements, and then focuses on the measured data that describe the bipolar coding/FM modulation with a bit rate of 4800 bit/s and an RF channel spacing of 25 kHz. The basic error characteristics of the channel are presented by (i) the average bit error rate, (ii) the gap length distribution and (iii) the error burst length distribution. The measured error pattern was used in conjunction with some known error control techniques, to examine their effectiveness in reducing the overall errors. In particular, the block coding techniques used in the AMPS system were evaluated and compared with other, simpler techniques having higher coding rates. The results are presented in the form of curves relating the packet error rate to the packet length.