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: A method and an apparatus for supporting connectivity of Peer-to-Peer (P2P) communication in a mobile communication system are provided. An operating method of a Mobile Station (MS) for providing the connectivity of the P2P communications in the mobile communication system includes connecting P2P communications by searching for a correspondent MS in a first Base Station (BS), determining whether a direct P2P communication is feasible with the correspondent MS in the P2P communications and, when the direct P2P communication is not feasible, setting a P2P relay using the first BS.

Abstract: A handover apparatus and method in a communication system having a macro BS and a plurality of micro BSs in one cell are provided. A handover apparatus includes a macro BS for generating a plurality of messages, each messages respectively corresponds to one of a plurality of group areas defined by grouping service areas of the micro BSs and includes information about BSs to which MSs of the group area can perform handover. The macro BS also generates group area information indicating locations of the group areas, broadcasts the plurality of messages and the group area information to the cell, and manages handover of MSs based on the plurality of messages and the group area information.

Abstract: An apparatus and a method for a terminal handover between systems using different Frequency Allocations (FAs) are provided. The method includes broadcasting an indication signal to inform of existence of the terminal in a coverage of a macro base station to which an indoor base station is registered; and when receiving a handover command message of the indoor base station, from the macro base station, performing a handover procedure to the indoor base station. The base station can efficiently utilize the control channel resource and the user terminal needs not to conduct the unnecessary scanning procedure. Thus, the time and the power required for the scanning can be spared.

Abstract: An apparatus and method for allocating a resource to a Mobile Station (MS) connected to a Relay Station (RS) in a broadband wireless communication system are provided. In the broadband wires communication system, a Base Station (BS) includes a transmitter for transmitting a pilot signal transmission request message to an MS, and a scheduler for frequency-selectively allocating a resource to the MS by using channel information upon receiving from an RS the channel information estimated using the pilot signal.

Abstract: An apparatus and method for transmitting/receiving a Channel Quality Information (CQI) in a communication system are provided. A Mobile Station (MS) receives first information indicating a representative MS selected from a group of MSs located within a preset range and in similar channel statuses, the group including the MS, determines from the first information whether the MS is designated as the representative MS, and transmits a CQI of the MS as a representative CQI of the MSs included in the group to a Base Station (BS), if the MS is designated as the representative MS.

Abstract: An apparatus and method for transmitting an UpLink (UL) pilot using a scanning interval in a mobile communication system are provided. The method includes receiving a scanning response message including information on a UL pilot channel allocation mode from a serving Base Station (BS), measuring each DownLink (DL) channel state using DL signals of one or more neighboring BSs and transmitting a UL pilot to each of the one or more neighboring BSs in the UL pilot channel allocation mode, during a scanning duration. Accordingly, both UL and DL Quality of Service (QoS) may be considered during a handover operation.

Abstract: A method for feeding back a Channel Quality Indicator (CQI) in a mobile communication system is provided. The method includes determining a number of subchannels for which the MS feeds back CQIs based on a preset feedback efficiency factor, selecting the determined number of subchannels in a descending order of channel quality, and feeding back the CQIs of the selected subchannels to a Base Station (BS).

Abstract: Selection of a relay station in a broadband wireless communication system is provided. In the broadband wireless communication system, a Base Station (BS) includes a sorter for generating a first index group in which indices of relay stations are sorted according to channel information between the BS and each relay station; a receiver for receiving a second index group in which the indices of the relay stations are sorted according to channel information between a Mobile Station (MS) and each relay station; and a selector for selecting a relay station to be used to communicate with the MS by using the first index group and the second index group.

Abstract: An apparatus and method for transmitting data by using Multi-round Contention Avoidance (MrCA) are provided. The method includes initializing a contention window for each of a plurality of contention rounds and setting a backoff counter corresponding to a size of the contention window for each contention round, starting from a first contention round to a last contention round, decrementing a backoff counter of a corresponding contention round in a time slot unit and transmitting data when the decremented backoff counter is zero and when the corresponding contention round is a last contention round. Accordingly, the number of contending nodes is exponentially decreased for each contention round, resulting in significant decrease in a collision probability in addition to improving fairness on channel use among users.

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: A handover apparatus and method in a communication system having a macro BS and a plurality of micro BSs in one cell are provided. A handover apparatus includes a macro BS for generating a plurality of messages, each messages respectively corresponds to one of a plurality of group areas defined by grouping service areas of the micro BSs and includes information about BSs to which MSs of the group area can perform handover. The macro BS also generates group area information indicating locations of the group areas, broadcasts the plurality of messages and the group area information to the cell, and manages handover of MSs based on the plurality of messages and the group area information.

Abstract: Provided is an apparatus and method for transmitting/receiving a message for a handover to a heterogeneous system in a BWA system. In the method, a neighboring BS information message containing the neighboring heterogeneous system BS information is generated according to the neighboring BS information message generation scheme of the serving system. The serving system BS has only to transmit information about a neighboring BS of the serving system, thus reducing a message overhead. Also, the neighboring heterogeneous system BS has only to transmit its own BS information within the corresponding coverage, thus enabling efficient use of control channel resources.

Abstract: A method and an apparatus for supporting connectivity of Peer-to-Peer (P2P) communication in a mobile communication system are provided. An operating method of a Mobile Station (MS) for providing the connectivity of the P2P communications in the mobile communication system includes connecting P2P communications by searching for a correspondent MS in a first Base Station (BS), determining whether a direct P2P communication is feasible with the correspondent MS in the P2P communications and, when the direct P2P communication is not feasible, setting a P2P relay using the first BS.

Abstract: An apparatus and method for transmitting/receiving a Channel Quality Information (CQI) in a communication system are provided. A Mobile Station (MS) receives first information indicating a representative MS selected from a group of MSs located within a preset range and in similar channel statuses, the group including the MS, determines from the first information whether the MS is designated as the representative MS, and transmits a CQI of the MS as a representative CQI of the MSs included in the group to a Base Station (BS), if the MS is designated as the representative MS.

Abstract: A method for feeding back a Channel Quality Indicator (CQI) in a mobile communication system is provided. The method includes determining a number of subchannels for which the MS feeds back CQIs based on a preset feedback efficiency factor, selecting the determined number of subchannels in a descending order of channel quality, and feeding back the CQIs of the selected subchannels to a Base Station (BS).

Abstract: An apparatus and method for transmitting an UpLink (UL) pilot using a scanning interval in a mobile communication system are provided. The method includes receiving a scanning response message including information on a UL pilot channel allocation mode from a serving Base Station (BS), measuring each DownLink (DL) channel state using DL signals of one or more neighboring BSs and transmitting a UL pilot to each of the one or more neighboring BSs in the UL pilot channel allocation mode, during a scanning duration. Accordingly, both UL and DL Quality of Service (QoS) may be considered during a handover operation.

Abstract: An apparatus and method for transmitting data by using Multi-round Contention Avoidance (MrCA) are provided. The method includes initializing a contention window for each of a plurality of contention rounds and setting a backoff counter corresponding to a size of the contention window for each contention round, starting from a first contention round to a last contention round, decrementing a backoff counter of a corresponding contention round in a time slot unit and transmitting data when the decremented backoff counter is zero and when the corresponding contention round is a last contention round. Accordingly, the number of contending nodes is exponentially decreased for each contention round, resulting in significant decrease in a collision probability in addition to improving fairness on channel use among users.

Abstract: Selection of a relay station in a broadband wireless communication system is provided. In the broadband wireless communication system, a Base Station (BS) includes a sorter for generating a first index group in which indices of relay stations are sorted according to channel information between the BS and each relay station; a receiver for receiving a second index group in which the indices of the relay stations are sorted according to channel information between a Mobile Station (MS) and each relay station; and a selector for selecting a relay station to be used to communicate with the MS by using the first index group and the second index group.

Abstract: An apparatus and method for allocating a resource to a Mobile Station (MS) connected to a Relay Station (RS) in a broadband wireless communication system are provided. In the broadband wires communication system, a Base Station (BS) includes a transmitter for transmitting a pilot signal transmission request message to an MS, and a scheduler for frequency-selectively allocating a resource to the MS by using channel information upon receiving from an RS the channel information estimated using the pilot signal.