(L,K) CDMA/aloha multiple-access system

The performance of the noisy slotted aloha random-access system in combination with L-out-of-K (L,K) code division multiple-access (CDMA) is discussed. A model is formulated based on the philosophy that collisions among few users are handled by the CDMA codes and collisions among many users are resolved by the aloha system. We show that for a lower signal-to-noise ratio (SNR), the hybrid system performs better than the conventional aloha scheme. Also, smaller (L,K) CDMA codes give superior results over larger codes.