Patent ID: 8412198

Claim:
A method for configuring an Internet Protocol (IP) address during a network entry process by a portable terminal in a wireless communication system, the method comprising: transmitting a ranging request message to a base station when an IP subnet has been changed, the ranging request message comprising a Medium Access Control (MAC) address of the portable terminal; receiving a ranging response message comprising IP address information from the base station, usable in a new IP subnet; and configuring a new IP address from the received IP address information, wherein the MAC address is used for determining whether the portable terminal has moved from another IP subnet, wherein the new IP address is configured using a combination of the MAC address and a network prefix, if the MAC address does not conflict with a MAC address of another portable terminal, wherein the new IP address is configured using a specific MAC address which is not being used in the new IP subnet, if the MAC address conflicts with the MAC address of another portable terminal, and wherein the new IP address is used for a signal transmission and reception of the portable terminal.