An efficient 4-level coded-CPM modem for a wireless local area network-coded-QPTM

A new modulation scheme, named coded-QPTM (quatenary phase transition modulation) is proposed for a local-area wireless network (wireless LAN) application. Coded-QPTM is essentially a continuous phase modulation scheme and encoding is executed under the principle of block coding to enlarge the modulated signal distance for Viterbi sequence estimation. A simple (10,9) code can improve the BER performance to almost the same value as that of QPSK. The above characteristics are obtained under the severely band-limited condition.