Abstract: A broadband wireless access (BWA) communication system includes a mobile subscriber station (MSS), a serving base station (BS) with which the MSS performs communication, and a plurality of neighbor BSs. The serving BS transmits, to the MSS, a handover request message including information on at least one recommended BS to which the MSS can perform a handover, among the neighbor BSs, and indication information indicating a fast handover, and transmits, to each of the recommended BSs, a handover confirm message indicating that the MSS will perform the fast handover.

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: A method and system are provided for transmitting broadcast service data in a wireless communication system using an Orthogonal Frequency Division Multiple Access (OFDMA) scheme in which data transmission is achieved through a downlink and an uplink within one frame. The system being connected to a broadcast server. The system and method include allocating a connection identifier (CID) to each broadcast service for identification of a broadcast service packet transmitted over the downlink, and transmitting broadcast service information for each broadcast service; and receiving a broadcast packet from the broadcast server, and transmitting a physical layer transmission information element (DL-MAP) including a broadcast service CID for the broadcast packet through the downlink0.

Abstract: An apparatus and a method for relay service in a wireless communication system are provided. A method for constituting a frame for a relay service in a wireless communication system includes configuring Downlink and Uplink subframes for a Base Station (BS) to transmit and receive signals to and from a Mobile Station via one or more relay stations over one or more communication zones. Thus, the frames for the multihop relay service can be constituted with ease, the multihop relay service can be provided not to drive the relay service data into a particular part of the frame, and the service coverage of the MS can be extended.

Abstract: A system for a periodic ranging in a BWA communication system. In the system, a receiver in a sleep mode of a wireless communication system receives a sleep mode transition message, which including first information relating to a timing point at which the periodic ranging is performed, from a transmitter, transits to the sleep mode, and performs the periodic ranging at a timing point corresponding to the first information. Accordingly, the periodic ranging of the receiver in the sleep mode can be performed.

Abstract: An apparatus and method for supporting a different system in a broadband wireless communication system using a multi-hop relay scheme are provided. A DownLink/UpLink (DL/UL) frame of a Base Station (BS) includes a legacy access zone for communicating with a legacy Mobile Station (MS), a relay zone for communicating with a legacy Relay Station (RS), and a new zone for communicating with a new MS. A DL/UL frame of an RS includes a legacy access zone for communicating with a legacy MS and a legacy relay zone for communicating with a new BS by legacy standards.

Abstract: An apparatus and method for supporting heterogeneous systems in a multi-hop relay wireless communication system are provided. In a method of transmitting and receiving a DownLink (DL) frame of a Base Station (BS) in a multi-hop relay wireless communication system employing heterogeneous systems, the DL frame of the BS includes a legacy zone for communication with a legacy Mobile Station (MS), an access zone of a new zone for communication with a new MS, and a relay zone of the new zone for communication with a new Relay Station (RS). The method includes transmitting DL data to the legacy MS in the legacy zone, transmitting the DL data to the new MS in the access zone of the new zone, and transmitting the DL data to the new RS in the relay zone of the new zone.

Abstract: A mobile station compliant with a legacy system and a mobile station compliant with a new system are both supported in a multihop relay broadband wireless communication system. A DownLink (DL) period of the Base Station (BS) includes a legacy zone for communicating with entities of a legacy system and a new zone for communicating with entities of a new system. Operations of the BS include transmitting DL data to entities of the legacy system via the legacy zone, and transmitting DL data to entities of the new system via the new zone which follows the legacy zone in a time axis.

Abstract: A method for supporting handover in a BWA communication system is provided. The system includes an MS, a serving BS, and a plurality of neighbor BSs. The coverage area of each of the BSs is divided into sectors using different subcarrier bands. The MS collects information broadcast from the serving BS on the serving BS and the neighbor BS, measures a signal level for each of the sectors of the serving BS and the neighbor BSs according to the collected information, and sends a handover request based on the measured signal level for each of the sectors. The serving BS broadcasts information on the serving BS and the neighbor BS to the MS, determines if the MS can perform a soft handover from its current sector to another sector upon receiving the handover request from the MS, and permits the MS to perform the soft handover if possible.

Abstract: A broadband wireless access (BWA) communication system includes a mobile subscriber station (MSS), a serving base station (BS) with which the MSS performs communication, and a plurality of neighbor BSs. The serving BS transmits, to the MSS, a handover request message including information on at least one recommended BS to which the MSS can perform a handover, among the neighbor BSs, and indication information indicating a fast handover, and transmits, to each of the recommended BSs, a handover confirm message indicating that the MSS will perform the fast handover.

Abstract: An apparatus and method for retransmitting of data in a wireless communication system are provided. The method includes transmitting data to at least one lower node, temporarily storing the data transmitted to the lower node, if ACKnowledgement (ACK) information of a relay link is not received for a predetermined time after data transmission or if the ACK information of the relay link is received from a lower Relay Station (RS), identifying if error occurrence information of an access link is received from the lower RS, and, if the ACK information of the access link is received from the lower RS, recognizing that data transmission to a Mobile Station (MS) succeeds.

Abstract: A system and method for transmitting a traffic indication message in a Broadband Wireless Access communication system. A base station (BS) transmits the traffic indication message to mobile subscriber stations (MSSs). The traffic indication message includes information on a number of MSS groups and information on a number of traffic indication indexes, each of the MSS groups includes a predetermined number of MSSs, and each of the traffic indication indexes is assigned to each of the MSS groups, and includes a bitmap including a predetermined number of bits. The predetermined number of bits is identical to the number of the MSSs included in each of the MSS groups, each of the predetermined number of the bits is assigned to each of the MSSs included in each of the MSS groups, and represents operation instruction information for each of the MSSs.

Abstract: A wireless multi-hop relay communication system includes a terminal for transmitting an Automatic Retransmission reQuest (ARQ) block of a Media Access Control (MAC) layer in an access link, an access link relay station for determining if there is an error in the ARQ block received on the access link and for sending the ARQ block to an upper node over a relay link when the ARQ block has no error, and a base station for determining if there is an error in the ARQ block received over the relay link.

Abstract: An apparatus and method for an admission control for a service flow in a broadband wireless access communication system using a multi-hop relay scheme is provided. In a method for operating a relay station in a broadband wireless communication system using a multi-hope relay scheme, a request message requesting an admission control decision for a service flow is received from an upper node. It is determined whether a requested QoS parameter set included in the request message is supportable. If the requested QoS parameter set is supportable, the request message is forwarded to a subordinate relay station corresponding to a next hop in a data transmission path. If the requested QoS parameter set is unsupportable, a response message indicating the unsupportability of the requested QoS parameter set is transmitted to a base station.

Abstract: An apparatus and a method for changing a Multicast and Broadcast Service (MBS) channel of a terminal in a broadband wireless communication system are provided. In the method, an overall channel scheduling information message comprising group information for Connection Identifications (CIDs) of all channels in service is received from a base station. Transmission information of an MBS channel scheduling information message corresponding to a group to which a CID of a current channel belongs is extracted from the overall channel scheduling information message. A relevant MBS channel scheduling information message is received from the base station using the extracted transmission information of the MBS channel scheduling information message. Transmission information of an MBS MAP message for a relevant CID is extracted from the MBS channel scheduling information message. Therefore, an MBS channel change of a terminal can be easily performed.

Abstract: A method for determining a number of ranging slots by a base station (BS) in a broadband wireless access (BWA) communication system. The method includes counting the number of mobile stations (MSs) that succeeded in ranging in a current frame, determining a ranging slot occupation ratio in the current frame, comparing a ranging slot occupation ratio of a previous frame with the ranging slot occupation ratio of the current frame, detecting an increase in the number of ranging-requesting MSs, if the ranging slot occupation ratio of the current frame is greater than the ranging slot occupation ratio of the previous frame, and determining the number of ranging slots of a next frame such that the number of ranging slots of the next frame is greater than the number of ranging slots of the current frame.

Abstract: Disclosed is a system and a method of signal transmission/reception by a mobile station in a wireless communication system. The method includes: transmitting a first sub-band preparation indicator, which indicates that the mobile station has been prepared for transmission/reception of a signal through a first sub-band, to a base station through a primary band; transmitting a first sub-band failure indicator to the base station through the primary band upon detecting failure in transmitting the first sub-band preparation indicator; receiving sub-band information on a second sub-band, which is different from the first sub-band, from the BS through the primary band; and acquiring synchronization with the second sub-band, so as to enable transmission/reception of a signal through the second sub-band based on the sub-band information.

Abstract: A method and an apparatus for reducing a handover delay in a broadband wireless communication system are provided. In a method for operating a terminal to reduce a handover delay in a broadband wireless communication system, a handover procedure is performed with a serving Base Station (BS) to obtain a dedicated ranging code and a Connection ID (CID). The dedicated ranging code is transmitted to one or more target BSs using the CID. Whether the dedicated ranging code is received is determined. Therefore, a handover delay and a chance of malfunction can be reduced.

Abstract: Provided are an apparatus and a method for performing a handover of a terminal in a wireless communication system. In the method, a ranging code is transmitted to a target base station on which a handover is to be performed. A ranging response message comprising Connection Identification (CID) update information is received from the target base station together with resource assignment information for transmission of a ranging request message. Therefore, fast resumption of downlink data reception of the terminal can be supported through fast CID update during a handover.

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.