It is an important research area in the Internet of Things (IoT) to maintain the communication continuity between the moving Mobile Nodes (MNs) in the IEEE 802.15.4 Low-power Wireless Personal Network (LoWPAN) and the Correspondent Nodes (CNs) in the IP network. In the existing mobile IPv6 protocols, such as MIPv6, HMIPv6 etc, some Signaling Packets (SPs) for mobility management have sizes larger than the maximum payload of the IEEE 802.15.4 MAC frame so that they are fragmented into multiple pieces carried in the LoWPAN, which increases the loss probability and the delay of the SPs. The proposed WPAN oriented MIPv6 (WoMIPv6) is able to reduce the sizes of the SPs to be less than 60 B using header compression technique so that the handoff caused by the MN crossing the boundary of two successive subnets is completed after a few small sizes of SPs are exchanged. In other words, each SP in the WoMIPv6 can be carried within a single IEEE 802.15.4 MAC frame without being fragmented. In addition, the delay in the WoMIPv6 is derived. Numeric analyses show WoMIPv6 performs better than HMIPv6 both in SP size and delay.