Abstract: Provided are an apparatus and method for upstream transmission of variable bit rate traffic in a Hybrid Fiber Coaxial (HFC) network. The apparatus includes: a VoIP signal processing unit for digitizing a voice of a speaker to create a voice packet, detecting a mute section to suppress packet generation, and generating an Service identification (SID) packet in the mute section; a storage unit for storing the voice packet and the SID packet created by the VoIP signal processing unit and notifying information on the stored packets; a VoIP activity determining unit for determining a voice activity based on the information on the stored packets notified from the storage unit; and a packet processing unit for including the voice activity transferred from the VoIP activity determining unit in the packets from the storage unit to encapsulate them and transmit it to a network device.

Abstract: A method for controlling operation modes of a medium access control layer by a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station and a serving base station providing service to the mobile subscriber station is provided. The method includes the steps of: mode-transiting into an idle mode when there is no data transmission between the serving base station and the mobile subscriber station during a predetermined first time interval in an awake mode; detecting movement of the mobile subscriber station in the idle mode into another paging zone covering a target base station, which is different from a paging zone covering the serving base station; and mode-transiting into the awake mode and performing location update together with the target base station when the movement of the mobile subscriber station is detected.

Abstract: A method for controlling operation modes of a medium access control layer by a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station and a serving base station providing service to the mobile subscriber station is provided. The method includes the steps of: mode-transiting into an idle mode when there is no data transmission between the serving base station and the mobile subscriber station during a predetermined first time interval in an awake mode; detecting movement of the mobile subscriber station in the idle mode into another paging zone covering a target base station, which is different from a paging zone covering the serving base station; and mode-transiting into the awake mode and performing location update together with the target base station when the movement of the mobile subscriber station is detected.

Abstract: An apparatus for determining a downstream topology in a hybrid-fiber-coaxial network includes: a signal branching unit for branching a signal received from a cable modem termination system into a plurality of branched signals; a plurality of signal selecting units for selectively receiving a frequency band signal corresponding to a specific downstream channel among the plurality of branched signals; a downstream topology determining unit for analyzing a downstream ambiguity resolution frequency list contained in a channel information message of a downstream primary channel received from the cable modem termination system, collecting in parallel channel information messages with respect to a plurality of downstream channels, and determining a downstream topology at a high speed using the collected channel information messages; and a plurality of packet generating units for setting downstream channel frequency bands of the signal selecting units under control of the downstream topology determining unit, and sen

Abstract: A mobile communication system using an orthogonal frequency division multiplexing (OFDM)/orthogonal frequency division multiple access (OFDMA) scheme. The method for assigning ranging codes in the OFDM/OFDMA communication system includes classifying rangings between a base station and a mobile subscriber station (MSS) of the OFDM/OFDMA communication system into an initial ranging, a periodic ranging, a bandwidth request ranging, and a handover ranging. A first number of ranging codes used for the rangings are created and a second number of ranging codes selected from the first number of ranging codes are assigned as handover ranging codes used for the handover ranging.

Abstract: A method for controlling operation modes of a medium access control layer by a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station and a serving base station providing service to the mobile subscriber station is provided. The method includes the steps of: mode-transiting into an idle mode when there is no data transmission between the serving base station and the mobile subscriber station during a predetermined first time interval in an awake mode; detecting movement of the mobile subscriber station in the idle mode into another paging zone covering a target base station, which is different from a paging zone covering the serving base station; and mode-transiting into the awake mode and performing location update together with the target base station when the movement of the mobile subscriber station is detected.

Abstract: A method for controlling operation modes of a medium access control layer by a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station and a serving base station providing service to the mobile subscriber station is provided. The method includes the steps of: mode-transiting into an idle mode when there is no data transmission between the serving base station and the mobile subscriber station during a predetermined first time interval in an awake mode; detecting movement of the mobile subscriber station in the idle mode into another paging zone covering a target base station, which is different from a paging zone covering the serving base station; and mode-transiting into the awake mode and performing location update together with the target base station when the movement of the mobile subscriber station is detected.

Abstract: A method for controlling operation modes of a medium access control layer by a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station and a serving base station providing service to the mobile subscriber station is provided. The method includes the steps of: mode-transiting into an idle mode when there is no data transmission between the serving base station and the mobile subscriber station during a predetermined first time interval in an awake mode; detecting movement of the mobile subscriber station in the idle mode into another paging zone covering a target base station, which is different from a paging zone covering the serving base station; and mode-transiting into the awake mode and performing location update together with the target base station when the movement of the mobile subscriber station is detected.

Abstract: A method is provided for performing an authentication procedure according to location registration and update for a mobile subscriber station (MSS) in a broadband wireless access (BWA) communication system. The system includes the MSS operating in idle mode to minimize power consumption, paging groups each being formed by a plurality of adjacent cells in which a plurality of MSSs are paged, base stations (BSs) for paging the plurality of MSSs within each paging group, and a server for controlling location registration and authentication for the plurality of MSSs. The server determines whether to approve a request for transition to the idle mode received from the MSS through a BS. If the server approves the request for the transition to the idle mode, it allocates authentication information to the MSS through the BS and registers location of the MSS.

Abstract: A method for managing a service flow of a mobile subscriber station (MSS) in a serving base station (BS) for a mobile communication system including the serving BS in communication with the MSS through a wireless access channel, and at least one active BS included in an active BS set of the MSS. Upon receiving a service flow management request from the MSS, the serving BS updates a service flow with the MSS, and transmits the updated service flow to the active BS using a predetermined message. Upon receiving a response message for the updated service flow from the active BS, the serving BS transmits service flow information of each active BS included in the response message to the MSS.

Abstract: An apparatus and a method for scheduling packets in a wireless communication system. The method includes the steps of dividing a transmission deadline of the packets for a destination into a first deadline, which is an end point of the transmission deadline, and a second deadline, which is allocated before the first deadline in consideration of a transmission channel state and a quality of service (QoS) of the packets, scheduling and transmitting the packets according to transmission priorities thereof, which are determined by a predetermined scheme, before the second deadline, and scheduling and transmitting the packets according to an approaching order of the packets with respect to the first deadline, if the packets have passed through the second deadline.

Abstract: A system for performing network re-entry upon handover of a mobile subscriber station (MSS) to a target base station (BS). Upon detecting handover of the MSS, the target BS detects network re-entry information necessary for network re-entry of the MSS from the serving BS, and transmits, to the MSS, the detected network re-entry information, information on an acknowledge (ACK) channel through which the MSS will respond that it has received the network re-entry information upon receipt of the network re-entry information, and ACK request information requesting the MSS to respond whether it has received the network re-entry information. The MSS receives the ACK channel information, and thereafter receives, from the target BS, the network re-entry information and the ACK request information, and a response transmits to the target BS which indicates that it has received the network re-entry information, through the ACK channel in response to the ACK request information.

Abstract: A method supporting a Hybrid Automatic Repeat Request (HARQ) between a subscriber station and a base station in a broadband wireless access communication system including. The method includes the steps of: transmitting at least one H-ARQ enabled uplink burst from the subscriber station to the base station; generating ACK/NACK information according to the received HARQ enabled uplink burst at the base station; mapping the generated ACK/NACK information to a bitmap at the base station; transmitting the bitmap through a downlink information from the base station to the subscriber station.

Abstract: Disclosed is a method for allocating a safety channel in a wireless communication system which divides a full frequency band into a plurality of subcarrier bands and includes subchannels, each of which is a set of a predetermined number of subbands, each of which is a set of a predetermined number of contiguous subcarriers, where the subchannels include a safety subchannel allocated to particular subscriber stations (SSs), which is unused in a neighbor base station. The method comprises the steps of: transmitting, by the SS, its channel quality information to the base station (BS) when a channel quality of a subchannel allocated to the SS is less than to predetermined reference channel quality; and allocating a safety subchannel to the SS, by the BS upon receiving the channel quality information indicating that the channel quality of the subchannel is less than to the reference channel quality.

Abstract: A method for allocating a band Adaptive Modulation and Coding (AMC) channel in a wireless communication system that divides a full frequency band into a plurality of subcarrier bands and includes subchannels, each of which is a set of a predetermined number of neighbor subcarrier bands. Upon recognizing a need for a band AMC channel, a subscriber station (SS) sends a request for allocation of the band AMC channel to a base station (BS). Upon receiving the band AMC channel allocation request, the BS determines if it can allocate the band AMC channel requested by the SS, considering a resource situation of the BS, and transmits information on the determination to the SS.

Abstract: A method for controlling operation modes of a medium access control layer by a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station and a serving base station providing service to the mobile subscriber station is provided. The method includes the steps of: mode-transiting into an idle mode when there is no data transmission between the serving base station and the mobile subscriber station during a predetermined first time interval in an awake mode; detecting movement of the mobile subscriber station in the idle mode into another paging zone covering a target base station, which is different from a paging zone covering the serving base station; and mode-transiting into the awake mode and performing location update together with the target base station when the movement of the mobile subscriber station is detected.

Abstract: In a Broadband Wireless Access (BWA) communication system having at least two FAs, a base station (BS) requests a subscriber station (SS) to change its FA from the first FA to the second FA, upon detecting a need to change an FA of the SS from the first FA to the second FA while communicating with the SS. The SS informs the BS that it will change its FA from the first FA to the second FA in response to the FA change request, and then changes its FA from the first FA to the second FA. After changing the FA, the SS communicates with the BS through the second FA.

Abstract: A method for performing a handover by a subscriber station (SS) in a broadband wireless communication system including a serving base station (BS) communicating with the SS, and at least one neighbor BS neighboring the serving BS. The SS receives downlink signals from the serving BS and the neighbor BS; measures an arrival time difference between the downlink signal received from the serving BS and the downlink signal received from the neighbor BS; and transmits the measured arrival time difference to the serving BS.

Abstract: An apparatus and method for controlling operation states of a medium access control layer by a mobile subscriber station (MSS) in a broadband wireless access communication system. The method includes: state-transitioning into a sleep state or an idle state when there is no data transmitted between a base station and the MSS during a predetermined first time interval in an awake state; and performing a location change in the idle state when the mobile subscriber station moves from a first paging zone to a second paging zone, and state-transiting into the awake state when the mobile subscriber station in the idle state detects a paging to the mobile subscriber station. The method minimizes power consumption and maximizes efficiency in use of radio resources.

Abstract: A method for transmitting common control information from a base station to a plurality of subscriber stations in a wireless communication. The common control information includes first information transmitted in common to all of the subscriber stations and second information separately transmitted to the subscriber stations according to channel states of the subscriber stations. The first information is transmitted using an MCS (Modulation and Coding Scheme) level having a modulation scheme with a lowest order and a coding scheme with a lowest coding rate among all MCS levels available in the base station. The second information is transmitted using MCS levels that are adjusted by a predetermined level against MCS levels corresponding to channel states of the subscriber stations.