Physical Sidelink Control Channel (PSCCH) in Mode 2: Performance analysis

User Equipments (UEs) that send data must advertise the upcoming transmission by broadcasting signaling messages over the Physical Sidelink Control Channel (PSCCH). Thus, it is important for the network operator to define the PSCCH resource pool to maximize the probability that each UE will be able to successfully decode all of the control messages that appear on the PSCCH. For UEs operating in Mode 2 (i.e., outside the coverage area of an eNodeB), this is especially challenging because there is no base station present that can assign PSCCH resources. UEs must choose pool resources randomly, which can lead to collisions of transmitted messages. In addition, UEs are half-duplex and a poorly designed control channel resource pool can create a significant risk that a signaling message and its duplicate will be missed by a UE that transmits its own signaling message in the same pair of subframes. In this paper, we present an analytical model that allows us to develop closed form expressions for the distribution of the number of UEs that successfully receive a transmitted message on the PSCCH. This model can support PSCCH design by network operators, and can be used to investigate other aspects of D2D communications.