Envelope‐controlled digital modulation improving power efficiency of transmitter amplification—application to trellis‐coded 8 psk for mobile radio

Trellis-coded modulation (TCM) has good spectrum properties and excellent bit error rate (BER) performance. This paper presents the envelope control (EC) method which improves the transmitter power amplification efficiency of TCM for mobile radio. Applying EC to TCM leads to two new modulation schemes: smoothed envelope trellis-coded 8 PSK (SE-TC8PSK) and constant envelope TC8PSK (CE-TC8PSK). Modulation and demodulation techniques for SE-TC8PSK and CE-TC8PSK are created. The spectrum properties, BER performance, and power-conversion efficiency of SE-TC8PSK and CE-TC8PSK are calculated by computer simulations and compared with those of TC8PSK. EC greatly improves the power-conversion efficiency at the cost of degrading the spectrum properties and BER performance of both schemes.