In order to analyze the handover latency of CoMP, we first derive the average number of transmissions and retransmissions with considering CoAP retransmission mechanism incurring the transmission error. The author [4] studied the impact of the Signal to Noise Ratio (SNR) on the physical level packet loss rate of an 802.15.4 link. By [4], in 1, 1.5, 2, and 2.5 (dB) of SNR the packet loss rate P is shown in Equation (1) below: