Slotted ALOHA and CDPA: A Comparison of Channel Access Performance

The paper compares the performance of two channelaccess schemes suitable for the cellular environment, which, in particular, allow the packet capture and can deal with inter-cell interference. The first scheme is the well known S-ALOHA while the second one is the Capture Division Packetized Access, recently proposed. The comparison is analytically performed over a common system with a common analytical model. Despite the many analyses appeared on S-ALOHA, the one we develop is new because a throughput density uniformly distributed on the plane is considered in a multiple cell environment. The analysis clearly shows the effect of intra-cell and inter-cell interference on the ALOHA system and proves that a superior throughput is achieved by CDPA, which completely avoids intra-cell interference. Our analysis also provides insight about the effectiveness of power control on both systems.