Abstract:
A method for allocating a channel quality information channel (CQICH) in a communication system is disclosed. After fast switching from a serving anchor base station (BS) to a target anchor BS, a mobile station (MS) detects absence of a CQICH allocated from the target anchor BS. Upon detecting the absence of the allocated CQICH, the MS sends a request for allocating the CQICH to the target anchor BS. Upon receiving the CQICH allocation request, the target anchor BS detects a need to allocate a CQICH to the MS.
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 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:
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:
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:
An apparatus and method for transmitting and receiving a signal according to a change of downlink channel information by a mobile station in a broadband wireless access communication system. The method includes: detecting the change of the downlink channel information; receiving a report from a base station that there is data for the mobile station; and reporting the change of the downlink channel information to the base station, so that the base station and the mobile station have same downlink channel information.
Abstract:
An apparatus and a method for data retransmission in a multihop relay wireless communication system are provided. The retransmission method includes determining whether an error is detected in data received from an upper node; generating a message indicative of the data error; and sending the message to the upper node at a time that is not appointed with the upper node. Therefore, it is possible to reduce a retransmission delay time that occurs during synchronous retransmission.
Abstract:
Disclosed are a system and a method for assigning ranging codes in a communication system. The communication system classifies rangings between a transmission unit and a reception unit of the broadband wireless access communication system into an initial ranging, a periodic ranging, a bandwidth request ranging, and a drop ranging. The communication system creates a first number of ranging codes used for the rangings and assigning a second number of ranging codes selected from the first number of ranging codes as drop ranging codes used for the drop ranging.
Abstract:
A system for transmitting/receiving resource allocation information in a wireless mobile communication system is provided. A transmission apparatus allocates a data burst in a frame, the data burst including a two-dimensional region of a time domain and a frequency domain, and transmits resource allocation information on the allocated data burst. A reception apparatus receives the resource allocation information from the transmission apparatus, and detects a region of the frame where the data burst is allocated, using the received resource allocation information. The resource allocation information includes information on a start point and an end point of the data burst. The start point indicates a point which is spaced apart from an start point of the frame by a first offset value in the time domain, and is spaced apart from the start point of the frame by a second offset value in the frequency domain. The end point indicates a point which is spaced apart from the start point by a third offset value in the time domain, and is spaced apart from the start point by a fourth offset value in the frequency domain. The data burst is a two-dimensional rectangular region having a diagonal line segment connecting the start point to the end point.
Abstract:
Data retransmission apparatus and method in a wireless relay communication system are provided. It is checked whether an Acknowledgement (ACK) message or a Negative ACK (NACK) message for data is received from a Relay Station (RS), which receives the data from a Mobile Station (MS). Scheduling information for transmitting the data is transmitted to the RS, when the ACK message is received from the RS. Errors are checked for in of the data, when the data is received from the RS. The RS is requested to retransmit the data, when the data has an error. Accordingly, since the RS retransmits only the error-free data to the BS, the BS can enhance the data reliability.