Performance comparison of antenna diversity and slow frequency hopping for the TDMA portable radio channel

The authors present the performance of a TDMA (time-division multiple-access) system plan using two-branch antenna diversity, and compare it to that of other TDMA system plans using channel and time slot interleaving and that of slow frequency-hopping/burst-error-correction (SFH/BC). Results indicate that the system designer can tradeoff spectral efficiency by using a double-error-correction code with channel interleaving and SFH to make the SFH/BC system perform as well as a system interleaving two-branch antenna diversity. For the system which uses interleaving and SFH, the number of hopping frequencies required depends on the code used and on the design of the demodulator (i.e. hard vs. soft decisions). As long as the code is chosen such that the system can handle the complete failure of one of the hopping frequencies, it can achieve about the same outage probability or speech block dropping rate as the system using antenna diversity. However, this equality is exacted at the price of spectral efficiency. The decrease in required carrier/intermodulation ratio is not enough to offset the decrease in the number of available channel sets caused by the wider bandwidth required to transmit the lower rate code.<<ETX>>