A flexible modem structure for increased network capacity and multimedia transmission in GSM PCS

A reconfigurable Global Mobile Standard (GSM) compatible radio modem interface which doubles the number of simultaneous video and voice transmissions per channel is presented for personal communication systems (PCS). The result is that an average video frame rate of up 14 fps can be supported within a single TDMA time slot, doubling the number of conventional GMSK multimedia transmissions per GSM channel. The design employs an in-circuit reconfigurable cross-correlated FQPSK signal processing technique. This innovative network modem is reconfigured in-circuit for high bit rate data transmission or GSM compatible operation. Spectrum efficiency ν_f (b/s/Hz) is investigated in a nonlinear amplified (NLA) environment-providing a 6 to 9 dB advantage in power efficiency. Our results show that the GSM compatible configuration of a specific cross correlated FQPSK-KF implementation offers up to 5.1 dB improvement in E_b/N_o , power efficiency, and network capacity ν_T (erlangs/Hz m²) may be increased 76% over GMSK BT_b=0.3