Bit synchronization and timing sensitivity in adaptive Viterbi equalizers for narrowband-TDMA digital mobile radio systems

An adaptive Viterbi-MLSE equalizer for narrowband-TDMA (time-division multiple-access) digital mobile radio systems is presented which uses a straightforward channel sounding technique for fast periodic equalizer start-up. The equalizer is specifically tailored for the application with h=0.5 partial-response CPM (continuous-phase modulation) schemes such as GMSK or GTFM. Exploiting the features of the channel-sounding Viterbi equalizer, a simple sample timing and bit synchronization technique is developed which uses a free-running sampling clock. The timing sensitivity of a digital mobile radio receiver based on the presented equalization and synchronization concepts is studied by computer simulations.<>