Transmission Capacity of Full-Duplex-Based Two-Way Ad Hoc Networks With ARQ Protocol

This paper investigates the network capacity of bidirectional communication systems based on full-duplex transmission in ad hoc networks while satisfying both the delay and target outage constraints. Bidirectional full-duplex transmission (BFD) has been proposed as a way to increase the system performance of two-way communications with multiple antennas. This type of system enables simultaneous exchange of data between two nodes via the bidirectional use of spatial resources. As the node density is increased to improve network capacity, however, the network performance decreases because of the simultaneous transmissions of adjacent pairwise interferers. To overcome this capacity degradation, we apply an automatic repeat request (ARQ) protocol to two-way communications. We then extend the analysis of the transmission capacity (TC) to account for packet retransmissions within the maximum allowed delay while satisfying the target outage constraint for two extreme cases (high mobility and static). After determining the optimized maximum number of packet retransmissions, the network capacity of the BFD system is then investigated as a function of the effective node density, node mobility, and required delay and target outage constraints. We can conclude that the benefits for TC obtained through full-duplex transmission and packet retransmission by an ARQ protocol outweigh the increase in interference caused by the bidirectional use of spatial resources and packet retransmissions.