A Random Access Scheme with Physical-layer Network Coding and User Identification
Jasper Goseling (UT)
I provide an introduction to random access protocols for wireless communication networks and the challenges that emerge from applications like the internet of things. Next, I describe a slotted random access scheme that, that is based on physical-layer network coding, a concept that I will also introduce. The scheme uses signature codes that enable the receiver to detect which users are active in each round and which linear combination of packets is received. Feedback enables in each round, one of the users to drop a packet, keeping the queue sizes limited. It is proven that for a broad class of feedback mechanisms the scheme is stable in the sense that the receiver can eventually decode all packets. Numerical results demonstrate that the scheme performs well in terms of the expected queue size, the maximum delay as well as the expected number of retransmissions per packet.