On performance improvement of asynchronous CDMA systems through the use of orthogonal sequence spreading

The possible performance improvement of CDMA (code division multiple access) systems that utilize orthogonal sequence spreading was studied. It is shown, that by spreading the signals symbol by symbol, the performance of the system can be greatly improved. For a CDMA system with a processing gain of 128, for example, as much as 450% capacity gain can be obtained over the conventional systems. The obtainable gain is limited by the processing gain of the system. For systems with larger processing gain, the obtainable gain can also be larger.