Method of managing allocated address in low power wireless personal area network

A method of managing an address allocated by a coordinator in a Low power Wireless Personal Area Network (LoWPAN), comprising the steps of:

• receiving a first beacon data request message from a mobile node that has entered into a communication region of the coordinator;
• measuring a first Link Quality Indication (LQI) of the first beacon data request message;
• setting the first LQI as a minimum communication threshold value with the mobile node;
• setting an alarm region, based on the first LQI, that is an LQI range for sensing whether the mobile node leaves the communication region;
• if a second beacon data request message is transmitted from the mobile node, measuring a second LQI of the second beacon data request message;
• checking whether the second LQI is included in the alarm region;
• if the second LQI is included in the alarm region, periodically transmitting a node alive check message to the mobile node;
• and
• releasing an address allocated to the mobile node according to an LQI corresponding to each of response messages transmitted, in response to the node alive check message, from the mobile node.