Cross-correlation index and multiple-access performance of even-degree Gold codes

Abstract

It is well known that for any particular code of a spread-spectrum system, there is a maximum number of users that would be tolerated and that this number would be well below nominal full load. However, the proportion of the full code set that are actually available for use before the onset of system saturation is not well known. In this work, the author presents a simple but effective means for determining performance limits of spreading sequences. This work involves the development of a mathematical model, the concept of cross-correlation index and its use for the determination of the system loading capacity. The model was developed and tested for different sets of Gold codes, the outcome of which was found to agree with results of software simulations for the system. Results shows that cross-correlation index is very effective for determining upper limit of simultaneous users that a spread-spectrum system can support in practice with respect to its spreading sequences.