CTH06-5: Scalable TSC-Optimal Overloading of Binary Signature Sets

Recent advances in the area of binary sequences for code-division multiplexing provide us with minimum total-squared-correlation (TSC) optimal signature sets for (almost) all signature lengths L and set sizes K. The sets are scalable as long as K les L (underloaded systems) and non- scalable -in general require signature re-design/re-assignment as users enter or exit- when K > L (overloaded systems). In this paper, we derive new lower bounds on the conditional TSC of overloaded binary signature sets built on fixed full- load TSC-optimal sets. Overloading is allowed to be as high as 100%. Scalable designs that achieve the new bounds are then developed. To evaluate the performance of the proposed designs, we compare the TSC of our constructions to the unconditionally minimum achievable TSC values.