A digital narrow-band cellular system

In many areas of the United States, cellular systems are nearing full capacity. To alleviate this problem and allow for further growth, a compatible, more spectrally efficient system is needed. In addition, as the telecommunications network becomes fully digital, it will be desirable to provide digital services in cellular systems. In this paper a narrow-band digital FDMA cellular telecommunications system is proposed. The system uses low bit rate speech coding in conjunction with a linear modulation system to provide a spectrally efficient cellular service. The channel modem uses digital signal processing techniques. Because the system is digital, security and encryption, as well as data services, can be readily implemented. A cellular ISDN signaling channel will be incorporated as an integral part of the system. The system has been designed to provide immunity over a large range of delay spread conditions.