Hybrid automatic repeat request

Automatic repeat request

Wireless

Computer science

Network packet

Quantum mechanics

Telecommunications link

Power (physics)

Telecommunications

Selective Repeat ARQ

Physical layer

Real-time computing

Relay

Linear network coding

Physics

Computer network

IEEE Transactions on Mobile Computing

This paper investigates the information freshness of two-way relay networks (TWRNs) operated with physical-layer network coding (PNC). Information freshness is quantified by age of information (AoI), defined as the time elapsed since the generation time of the latest received information update. PNC reduces the communication latency of TWRNs by turning superimposed electromagnetic waves into network-coded messages so that end users can send update packets to each other more frequently via the relay. While sending update packets more frequently has the potential to reduce AoI, how to handle packet corruption in TWRNs has not been investigated. Specifically, if an old packet is corrupted in any hop of a TWRN, one needs to decide whether to drop or to retransmit the old packet, e.g., a new packet has more recent information but may take more time to be delivered. Therefore, we study the average AoI with and without automatic repeat request (ARQ) in PNC-enabled TWRNs. Interestingly, our analysis shows that neithe...

Age of Information in Physical-Layer Network Coding Enabled Two-Way Relay Networks