Spectrum spreading effect of bandwidth expansion on spectral efficiency of cellular systems

Based on a six cochannel interference model, the effect of bandwidth expansion/spectrum spreading beyond the baseband on the spectral efficiency of wideband and spread spectrum cellular systems is examined. The improvement in the signal to noise ratio/protection ratio as a result of bandwidth expansion is considered. The advantage in the protection ratio and the resulting expanded channel spacing are weighed using an equation devised by the authors to deduce whether or not such expansion is spectrally justifiable. Various analog and digital systems are considered. The Shannon model is treated as an ideal modulation system and single sideband (SSB) is taken as a reference where bandwidth expansion is not employed