Applications of differential phase statistics to studies of c3 and spread spectrum communications

Five papers have been prepared under this contract in which recently developed differential phase statistics have been successfully employed to obtain error rate performance of differential modulation systems operating under practical conditions. These practical conditions included power imbalance, phase-change offset, noise correlations and intersymbol interference. The modulation systems considered were binary conventional and symmetric DPSK, offset DPSK, and M-ary DPSK. The channels studied were both terrestrial and satellite. Closed form expressions, requiring some numerical integration, were obtained in all cases. Extensive performance curves showing the effects of the various impairments were presented. Because satellite link performance depends strongly upon the qualities of the uplink, as shown, it was concluded that a satellite repeater is much less effective than a detect and remodulate transponder in a severe jamming environment. Asymptotic approximations to M-ary DPSK were shown to extremely good, and it was suggested that more emphasis be placed on such methods as opposed to the more traditional, but much less accurate, use of bounds.