In this section, we analyze the performance of the handover latency of CoMP. The handover latency can dramatically increase due to the packet loss of signaling message, which may be caused by the collision, congestion, and system failure in both the wireless link and wired links. The retransmission of the handover signaling messages can greatly increase the transmission reliability in the constrained IoT networks. The CoMP employs the retransmission mechanism of CoAP to prevent the packet loss of the signaling message. Although this may increase the handover latency of CoMP, the reliability can be guaranteed. The CoAP retransmission algorithm is described below.