Graph theoretic multiple access interference reduction for CDMA based radio LAN

In ad hoc W-CDMA wireless LANs, simultaneous transmissions between transmitter-receiver pairs generate Multiple Access Interference (MAI), which limits the throughput. Reducing MAI increases this throughput limit. This is achieved by scheduling transmissions such that the average number of simultaneous transmissions in each frame is reduced. MAI is minimized by allowing the least interfering links to transmit together. This paper proposes a graph theoretic algorithm that groups all links into a minimum number of subsets, based on the objective of minimizing MAI in each set. Simulations show that the proposed technique achieves around 100% improvement in system capacity over the scheme where all links transmit simultaneously.