Abstract: Disclosed is a method for recognizing by a Mobile Subscriber Station (MSS) whether a serving Base Station (BS) retains connection information in a mobile communication system including the serving BS for providing a service to the MSS and a target BS adjacent to the serving BS. The method includes the steps of receiving a handover request message from the serving BS, the handover request message including a resource remain type field representing whether the connection information having been set with the serving BS is retained, and a resource retain time field representing a connection information-retaining time by the serving BS, and recognizing that the serving BS retains the connection information during a time determined by a value of the resource retain time field.

Abstract: In a BWA communication system, an MSS changes its connection from the serving BS to the target BS, and sends the target BS a report indicating that the MSS will change its connection upon detecting occurrence of a pingpong effect in a process of performing a network re-entry operation with the target BS. The target BS sends the serving BS a notification indicating that the MSS will change its connection. Upon receiving from the MSS a report indicating that it will change its connection to the serving BS, the serving BS allocates a contention-free-based ranging resource to the MSS so that the MSS connects a communication service with the serving BS using the contention-free-based ranging resource, minimizing a service delay.

Abstract: A method and a system for periodic ranging in a sleep mode of a broadband wireless access communication system having an awake mode in which data to be transmitted between a mobile subscriber station (MSS) and a base station (BS) exists and the sleep mode in which data to be transmitted between the MS and the BS does not exist, the sleep mode having a sleep interval and a listening interval, the MSS being capable and incapable of receiving data in the listening interval and in the sleep interval, respectively. The BS reports to the MSS in a listening interval before the sleep interval that the MSS must perform the periodic ranging in the sleep interval when the BS detects that it is necessary for the MSS in the sleep mode to perform the periodic ranging at a particular time point in the sleep interval.

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 transmitting a traffic indication message for directing a mobile subscriber station (MSS) in a sleep mode to transition to an awake mode in a Broadband Wireless Access communication system supporting the sleep mode and the awake mode. This method includes the steps of individually allocating, to MSSs belonging to a corresponding base station, corresponding areas indicating traffic instructions for the MSSs in a traffic indication field in the traffic indication message, and indicating state transition instructions in the areas allocated to the MSSs, before transmitting the traffic indication message to the MSSs.

Abstract: A system and method for dynamically allocating a frame cell (FC) and subchannel (FC/subchannel) is disclosed. An access point receives channel quality information (CQIs) which is fed back from a plurality of access terminals on an FC-by-FC basis, and determines a modulation and coding scheme (MCS) to be applied to each of the access terminals. If access terminals whose FCs/subchannels must be changed are detected from the plurality of the access terminals, the access point sends an FC/subchannel change request for the detected access terminals to an access router. The access router generates weights for all FCs, allocates an FC/subchannel set by selecting a predetermined number of FCs/subchannels considering the weights of the FCs for the access terminals corresponding to the received FC/subchannel change request, and transmits information on the allocated FC/subchannel set to the access point.

Abstract: Disclosed are a system and a method for selecting a new serving base station when a drop occurs in a mobile subscriber station in a broadband wireless access communication system including the mobile subscriber station, a serving base station communicating with the mobile subscriber station, and a plurality of neighbor base stations, different from the serving base station. The mobile subscriber station receives information related to the neighbor base stations from the serving base station communicating with the mobile subscriber station. The mobile subscriber station monitors the frequency bands of the neighbor base stations included in the information related to the neighbor base stations if the drop is detected in order to detect target base stations capable of serving as a new serving base station for communicating with the mobile subscriber station when the drop occurs in the mobile subscriber station according to a monitoring result for the frequency bands of the neighbor base stations.

Abstract: Disclosed is a system and a method for controlling a handover of a mobile subscriber station in a broadband wireless access communication system. When serving base station determines to perform a handover of the mobile subscriber station, neighbor base stations to which the mobile subscriber station can be handed over, from among neighbor base stations of the mobile subscriber station, are determined based on a service quality level of service being currently provided to the mobile subscriber station. A handover request signal containing information related to the determined neighbor base station to which the mobile subscriber station can be handed over is transmitted to the mobile subscriber station.

Abstract: Disclosed is a method for enabling a mobile station existing in a serving cell area to perform a handover procedure in a broadband mobile communication system including the mobile station, a serving base station providing a service to the mobile station, and one or more target base stations containing at least one target cell area overlapping with the serving cell area occupied by the serving base station. The method includes transmitting a handover request message from the mobile station to the serving base station when it is detected that a performance of a handover is necessary; and transmitting a handover indication message containing handover cancel information to the serving base station when the mobile station determines a cancel of the handover while the mobile station is being handed over to one or more target base stations by the serving base station.

Abstract: A bandwidth allocation method for an uplink data transmission between a mobile subscriber station and a base station in a broadband wireless access communication system. The method includes inserting type information of a service requested by the mobile subscriber station into the access channel signal and transmitting the access channel signal to the base station, receiving uplink scheduling information according to the type of the service requested by the mobile subscriber station from the base station, and transmitting data using a transmission bandwidth allocated according to the uplink scheduling information.

Abstract: A method and apparatus for transmitting a DL-WUCH for a mode transition in a sleeping state in a broadband wireless communication system are provided. In the broadband wireless communication system, a base station (BS) transmits control information to a plurality of subscriber stations (SSs) on a common control channel. To demodulate a control channel signal received from the BS, an SS receives a wakeup channel signal which indicates whether the control channel signal includes control information for the SS, reads a wakeup channel indicator at a predetermined position assigned to the SS of the wakeup channel signal, and determines whether to demodulate the control channel signal according to the wakeup channel indicator.

Abstract: Dynamically allocating a frame cell (FC)/subchannel in a mobile communication system by an access point that receives channel quality information (CQIs) fed back from access terminals, determines a modulation and coding scheme (MCS) to be applied to the access terminals based on the CQIs, and if access terminals whose FCs/subchannels must be changed are detected from the access terminals, sends an FC/subchannel change request to an access router. The access router allocates an FC/subchannel set by selecting a number of FCs/subchannels according to the FC/subchannel change request, and transmits information on the allocated FC/subchannel set to the access point. The access point selects and allocates a particular FC/subchannel from among FCs/subchannels in the FC/subchannel set information to the access terminals whose FCs/subchannels must be changed, based on CQIs last received from the access terminals.

Abstract: A system and method for dynamically allocating channels in a wireless communication system including multiple sub-channels and multiple frame cells, each of the sub-channels being an assembly including a preset number of sub-frequency bands divided from an overall frequency band, the frame cells using each of the sub-channels as a basic transmission unit and having a frequency domain and a time domain occupied by the sub-channels. A mobile station transmits channel quality information of frame cells to an access point. An access router transmits channel allocation information about the multiple frame cells and sub-channels determined according to the received channel quality information to the access point, and the access point receives the channel allocation information about the multiple frame cells and sub-channels, compares the channel allocation information with newest channel quality information, and allocates a sub-channel of a frame cell selected according to the comparison to the mobile station.

Abstract: Disclosed is a method for enabling a subscriber station to shift from a sleep mode to an awake mode in a broadband wireless access communication system including the sleep mode in which there exists no data to be transmitted between the subscriber station and a base station, and the awake mode in which there exists data to be exchanged between the subscriber station and the base station. The method includes measuring a Carrier-to-Interference and Noise Ratio(CINR) with respect to the base station in a time interval for monitoring a received signal during the sleep mode; and shifting from the sleep mode to the awake mode when the measured signal-to-noise ratio is less than a first threshold value set in advance.

Abstract: A method for mode transition of a subscriber station between a sleep mode and an awake mode in a broadband wireless access communication system including a base station and at least the subscriber station, the subscriber station having data to transmit in the awake mode and not having data to transmit in the sleep mode is disclosed. The method includes receiving a dedicated orthogonal code from the base station and transiting into the sleep mode in the awake mode, the dedicated orthogonal code being allocated exclusively to the subscriber station; and in the sleep mode, transmitting a message to the base station by means of the dedicated orthogonal code in order to transit into the awake mode.

Abstract: Disclosed is an efficient random access method which enables a subscriber station to gain access to an uplink in broadband mobile communication system including the subscriber station and a base station. The method enables a subscriber station to perform re-access to a base station at a high speed in the mobile communication system, in which an access channel is allocated so that the subscriber station and the base station can transmit a message to each other using a code within a predetermined period of time, wherein, the method includes the steps of: the subscriber station receiving a request rejection message including a dedicated code in response to a request message transmitted from the subscriber station to the base station through the access channel; and the subscriber station checking the received request rejection message, and re-transmitting the request message in a contention-free method corresponding to the dedicated code which is included in the request rejection message.

Abstract: Disclosed is a method for controlling an operational state of a medium access control layer in a broadband wireless access communication system. The method includes the steps of performing an uplink access of a contention-based scheme to an access point using resources required to perform the uplink access according to the contention-based scheme when data to be transmitted in an access state is detected, and being allocated resources required to perform an uplink access of a contention-free scheme from the access point in a case of failing in the uplink access of the contention-based scheme; and performing a state transition from the access state into the traffic state in a case of having been allocated the resource required for the contention-free scheme, and performing the uplink access of the contention-free scheme to the access point using the allocated resource in the traffic state.

Abstract: A system for transmitting a message for generating an Internet Protocol version 6 (IPv6) address is provided. The system includes at least one access terminal, an access point, and a router. The access terminal transmits a first medium access control (MAC) layer connection message including its own MAC address and a fast address setup indication field to the access point. The access point receives the first MAC layer connection message from the access terminal, and determines whether a duplicate MAC address of the MAC address of the access terminal exists in the same sub-network.

Abstract: A broadband wireless access communication system having a sleep mode in which there is no data to be transmitted or received to/from a base station by a subscriber station, and an awake mode in which there is data to be transmitted or received to/from the base station by the subscriber station. The subscriber station sets a next sleep mode after a sleep interval between a start time of the sleep mode and a start time of the awake mode has reached a given maximum window value. The subscriber station receives a traffic indication message indicating absence of data to be transmitted from the base station after the start time of the awake mode; transmits a sleep request message to the base station; receives a response message to the sleep request message from the base station; and then operates in the next sleep mode.

Abstract: A method for measuring/reporting a channel quality in a broadband wireless access communication system. The method for reporting channel qualities of active BS and neighbor BSs measured by an MSS to the active BS when the MSS exists in a specific area covered by the active BS and neighbor BSs in a communication system includes the steps of: a) receiving channel quality report information indicative of channel periods of the channel qualities from the active BS, and receiving channel quality measurement information associated with individual channel qualities of the neighbor BSs and the active BS from the active BS; b) measuring SINRs of the neighbor BSs and the active BS according to the channel quality measurement information; and c) reporting the measured SINRs of the neighbor BSs and the active BS to the active BS.