Spectrum efficiency and digital cellular

A spectrum-efficiency formula for cellular systems has been derived and used to compare digital and analog systems. Since the digital system is always less susceptible to interference, the tolerable interference level can be higher; in other words, the cochannel reuse distance can be less. This reuses distance proves that digital cellular is a spectrum-efficient system. In order to take advantage of digital nature and implement digital systems in cellular structures, several schemes can be introduced to further increase the spectrum efficiency. A theoretical analysis is carried out to indicate the advantages of developing digital cellular systems