Abstract: A method and system for encrypting data in a wireless communication system are provided. The system includes a first node for generating a first encryption key using a plurality of encryption key parameters when performing authentication with a second node, for changing a second parameter among the plurality of encryption key parameters to generate a second encryption key being identical to the first encryption key, if a first parameter among the plurality of encryption key parameters is changed during re-authentication between the first node and the second node, for generating the second encryption key using the changed first parameter and the changed second parameter, and for encrypting data to be transmitted to the second node using the second encryption key.

Abstract: A method and apparatus for supporting a Short Message Service (SMS) of a Mobile Station (MS) during an idle mode in a wireless communication system are provided. An MS operation method for supporting an SMS in a wireless communication system includes receiving an SMS message from a Base Station (BS) through a ranging message in an idle mode, upon receiving the SMS message from the BS, starting a timer, while the timer operates, waiting UpLink (UL) resource allocation for transmission of an ACKnowledge (ACK) message about the SMS message, and, upon being allocated a UL resource for the ACK message transmission, transmitting the ACK message using the UL resource.

Abstract: A system and method for periodic ranging in sleep mode in a communication system are provided, in which an MS is allocated an uplink burst from a BS and transmits a first message in the allocated uplink burst to the BS, the first message indicating that the MS is alive during sleep mode.

Abstract: A method and system for encrypting data in a wireless communication system are provided. The system includes a first node for generating a first encryption key using a plurality of encryption key parameters when performing authentication with a second node, for changing a second parameter among the plurality of encryption key parameters to generate a second encryption key being identical to the first encryption key, if a first parameter among the plurality of encryption key parameters is changed during re-authentication between the first node and the second node, for generating the second encryption key using the changed first parameter and the changed second parameter, and for encrypting data to be transmitted to the second node using the second encryption key.

Abstract: A method and apparatus for supporting a Short Message Service (SMS) of a Mobile Station (MS) during an idle mode in a wireless communication system are provided. An MS operation method for supporting an SMS in a wireless communication system includes receiving an SMS message from a Base Station (BS) through a ranging message in an idle mode, upon receiving the SMS message from the BS, starting a timer, while the timer operates, waiting UpLink (UL) resource allocation for transmission of an ACKnowledge (ACK) message about the SMS message, and upon being allocated a UL resource for the ACK message transmission, and transmitting the ACK message using the UL resource.

Abstract: Provided is a system and method for performing a ranging process in a communication system. If a Subscriber Station (SS) detects the insufficiency of UpLink (UL) resources for transmission of a Ranging Request (RNG_REQ) message during the ranging process, it transmits a UL resource allocation request message requesting additional allocation of the UL resources to a Base Station (BS) for additional transmission of the RNG_REQ message to cause the BS to additionally allocate the UL resources for the additional transmission of the RNG_REQ message.

Abstract: A system and method for periodic ranging in sleep mode in a communication system are provided, in which an MS is allocated an uplink burst from a BS and transmits a first message in the allocated uplink burst to the BS, the first message indicating that the MS is alive during sleep mode.

Abstract: Provided is a system and method for performing a ranging process in a communication system. If a Subscriber Station (SS) detects the insufficiency of UpLink (UL) resources for transmission of a Ranging Request (RNG_REQ) message during the ranging process, it transmits a UL resource allocation request message requesting additional allocation of the UL resources to a Base Station (BS) for additional transmission of the RNG_REQ message to cause the BS to additionally allocate the UL resources for the additional transmission of the RNG_REQ message.