Spectral efficiency of a multitone frequency hopping system for personal communication systems

Different spread spectrum techniques have been proposed for future mobile radio systems. The two main methods of spreading the spectrum have been to use either a direct sequence spreading or a frequency hopping spreading. The authors analyze an alternative multiple access scheme, multitune frequency hopping. The choice of frequencies is made randomly with the constraint that each frequency is not used more than once in each cell. With this random channel allocation one can avoid both frequency planning and intra-cell interference. Other advantages are frequency diversity, frequency interleaving and no problems regarding time dispersion. For a given minimum transmission quality constraint the authors define, a spectral efficiency measure. Further, they derive the spectral efficiency of the proposed system when a pilot tone MPSK modulation has been used. Even though they transmit a pilot tone for each used frequency, the resulting spectral efficiency of the proposed system compares favorably with other proposals for future mobile radio systems