Cross-correlated correlative FQPSK modulation doubles the capacity of PCS networks

A new cross-correlated correlative modulation scheme is presented as a means of doubling the network capacity of personal communications systems (PCS). System performance is studied in a non-linear amplified channel for 6 to 9 dB improved power efficiency. The system is analyzed for adjacent channel interference (ACI) and bit error rate (BER) performance in a Rayleigh faded cellular network. Results show that modified correlative encoding achieves a spectral efficiency of 1.83 b/s/Hz, a 62% improvement over the European DECT standard GMSK BT_b =0.5 and 35% improvement over GMSK BT_b=0.3 in the DCS1800 and proposed PCS1900 standards. BER performance is improved up to 5 dB over coherent GMSK BT_b=0.3. Another advantage of this technique is that the degree of circuit complexity is low, and it is compatible with traditional GMSK or OQPSK receivers. By selecting different cross correlation parameters this modulation scheme offers dual-mode operation; one optimized for high data rate applications, and the other fully compatible with GMSK