Spectral shaping using coded modulation for mobile radio

Spectral efficiency for land mobile radio (LMR) channels is primarily limited by adjacent channel interference (ACI). Conventional digital modulation schemes do not achieve current specifications for ACI at high data rates, in the absence of powerful interference mitigation schemes. A novel trellis coded modulation scheme (TCM) scheme was presented by S. Chennakeshu et. al., (see Proc. Fifth Tirennia International Workshop, Tirennia, Elsevier, p.329-40, 1991) that has the potential to provide high data rates and at the same time, mitigate adjacent channel interference. The main idea was that the TCM scheme must be optimized to provide the desired spectral shaping. The authors explore this idea further and show how the various components of the system can be optimized to provide the desired gains in spectral shaping