Wireless access technologies have been extensively developed aiming to give users the ability to connect to their expected networks anytime, anywhere. This leads to an increment of the number of wireless interfaces integrated into a single mobile device, hence, it allows the device to be able to connect to multiple access networks. However, in some specific cases such as natural disasters, having an uncorrupted and timely information exchanging means is critical for affected victims to survive or to connect to the outside world. This is because the essential network infrastructures in these cases could be destroyed causing a large number of systems to stop working. In that cases, the victims need a heterogeneous communications network in which they can communicate, without a doubt, by using different wireless access technologies, i.e., Bluetooth or Wi-Fi. The network must also be able to smoothly change the access technologies, or called a vertical handover, to ensure QoS for