Abstract: A method for generating a preamble sequence in an orthogonal frequency division multiplexing (OFDM) communication system having A subcarriers in a frequency domain. The method comprises generating a length -M×N preamble sequence, where M×N is less than A, by using a length-N Golay complementary sequence and a length-M Golay complementary sequence; and assigning elements constituting the preamble sequence to M×N subcarriers among the A subcarriers on a one-to-one mapping basis, assigning null data to the remaining subcarriers excluding the M×N subcarriers from the A subcarriers, and then IFFT-transforming the assigned result into time-domain data.

Abstract: A method and apparatus for allocating pilot carriers adaptively in an OFDMA communication system are disclosed. To improve phase error estimation performance and optimize the number of pilot carriers allocated to each sub-channel, an OFDMA transmitter changes the number of pilot carriers for a sub-channel according to the status of the sub-channel. Consequently, less pilot carriers are allocated to a sub-channel in a good state, reducing power consumption and more pilot carriers are allocated to a sub-channel in a bad state, improving channel estimation performance despite increased power consumption.

Abstract: An apparatus and method for processing a handover complete signal in a multi-hop relay BWA communication system are provided in which a BS detects a source node of a Mobile Station (MS), when the MS completes network reentry, and transmits a handover complete message for the MS to the source node.

Abstract: A signal transmission/reception apparatus of a communication system. The signal transmission apparatus receives an information vector, encodes the information vector into a structured Low Density Parity Check (LDPC) codeword using a structured LDPC coding scheme, and transmits the generated structured LDPC code to the signal reception apparatus. Then the signal reception apparatus receives a signal, and detects an information vector by decoding the received signal using a decoding scheme corresponding to the structured LDPC coding scheme used in the signal transmission apparatus.

Abstract: Disclosed is a method and system for performing a sleep mode operation in a wireless communication system. If there is a need to set a sleep interval of a receiver, a transmitter selects the sleep interval setting indicator for controlling sleep interval parameter setting, and transmits the selected sleep interval setting indicator to the receiver. A receiver receives from the transmitter a sleep interval setting indicator for controlling sleep interval parameter setting, and sets a sleep interval parameter according to the sleep interval setting indicator.

Abstract: An apparatus and method for supporting an optimized network reentry procedure in a multihop relay Broadband Wireless Access (BWA) communication system are provided. The communication method for an RS in a multihop relay cellular communication system, includes receiving a HO-notify message, which contains information of an MS handed over to the RS, from a Base Station (BS); and performing an optimized network reentry procedure with the MS using the MS information of the HO-notify message. By defining the RS-BS signaling to provide the RS with information as to the MS handed over to the RS, the optimized network reentry procedure can be carried out between the RS being the target node and the MS.

Abstract: An apparatus and method for configuring a subframe to support a relay service in a multi-hop relay BWA communication system are provided, in which a first zone of a subframe is configured for at least one of communication between a BS and a first MS within the coverage area of the BS and communication between at least one RS and a second MS within the coverage area of the at least one RS, and a second zone of the subframe is configured for at least one of communication between the BS and the at least one RS and communication between the at least one RS and another RS.

Abstract: Disclosed are an apparatus and method of a Relay Station (RS) in a multihop relay Broadband Wireless Access (BWA) communication system. The method includes an RS for receiving a signal level threshold of the MS from a Base Station (BS), measuring a signal level of the MS, and transmitting the MS signal level to the BS when the measured signal level is greater than the signal level threshold; and the BS for transmitting the MS signal level threshold to one or more RSs and receiving MS signal levels from the RSs.

Abstract: A method for transmitting and receiving data in a communication system. The method includes grouping, by a Base Station (BS), Mobile Stations (MSs) using a real-time service, into groups, allocating burst blocks to the groups, and allocating data bursts of burst blocks to the MSs; and determining, by each MS, whether its own uplink burst is allocated, and transmitting data to the BS through a sub-burst of a burst block allocated to a group to which each MS belongs.

Abstract: Disclosed is a power saving method for a wireless communication apparatus that operates in a sleep mode during a predetermined duration by exchanging Media Access Control (MAC) messages with a base station in order to reduce power consumption when there is no transmission/reception data. According to the power saving method, switching is made between the sleep mode and a normal mode by transmission data generated by an upper layer. In the power saving method, an active mode switching is performed by recognizing the start and end of data transmission/reception in the upper layer, thereby preventing unnecessary power consumption caused by a listening interval of a fixed length.

Abstract: Opportunistic packet scheduling apparatus and method in a multihop relay wireless access communication system are provided. The method includes aggregating channel condition information which are estimated and reported by Mobile Stations (MSs) and a Relay Station (RS) for each MS path in a cell, determining a Modulation and Coding Scheme (MCS) level which corresponds to the aggregated channel condition information for a corresponding hop of each MS path, determining a transmittable coded packet size and a number of subchannels required for the packet transmission depending on the determined MCS level, and calculating a current radio resource efficiency of the corresponding MS path using the determined coded packet size and the determined number of the subchannels.

Abstract: A preamble sequence generating apparatus and method in a BWA communication system using OFDM. An ARM code generator generates at least one ARM code of a different length. A sub-carrier selection and frequency mask unit maps a second number of ARM code components to a second number of sub-carriers among a third number of OFDM sub-carriers distributed equally in a frequency band and maps null components to sub-carriers excluding from the second number of sub-carriers. Here, the second number being the number of (the components of the ARM code) minus (a DC component and a first number of ARM code components set to prevent adjacent channel interference). Then, an IFFT generates a preamble sequence by inverse-fast-Fourier-transforming the sub-carriers received from the sub-carrier and frequency mask unit.

Abstract: An apparatus and method of transparently relaying a signal in a direct link and a relay link using the same frequency band in a multihop relay Broadband Wireless Access (BWA) communication system. The method includes designating a start point of an asynchronous frame of the relay link by taking into account of a broadcast channel transmission interval of the direct link frame; and making a frame interval of the relay link null, where a transmission (Tx) mode of the direct link overlaps with another Tx mode. Accordingly, serving cell service coverage expansion and backward compatibility are achieved and a frame is constructed by selecting an optimum frame interval according to system information of the serving cell service. Therefore, efficient wireless access service can be provided.

Abstract: Apparatus and method of providing transparent relay service to a Mobile Station (MS) in a multihop relay Broadband Wireless Access (BWA) communication system. The communication method includes checking, at at least one relay station (RS), a sounding channel allocated to an MS by analyzing a message broadcast from a Base Station (BS); measuring, at the BS, an BS-MS signaling level using a sounding signal of the MS, the sounding signal received in the sounding channel; measuring, at the at least one RS, an RS-MS signaling level using a sounding signal of the MS, the sounding signal received in the sounding channel; reporting, at the at least one RS, the RS-MS signaling level measurement value to the BS; and selecting, at the BS, an RS suitable for the MS using the BS-MS signaling level measurement value and at least one RS-MS signaling level measurement value reported from the at least one RS. Accordingly, the BS can select a suitable RS for the MS by taking into account the RS-MS channel status.

Abstract: An apparatus and method for selecting an RS using an RS preamble signal in a multi-hop relay BWA communication system are provided, in which a BS sends preamble channel allocation information to at least one RS, the at least one RS sends a preamble to an MS according to the preamble channel allocation information, the MS measures the signal strength level of the preamble received from the at least one RS and reports the signal strength level to the BS, and the BS selects an RS for providing a relay service to the MS according to the signal strength level.

Abstract: A method of requesting and allocating an upstream bandwidth in an RS in a multi-hop relay BWA communication system is provided. The RS receives an upstream bandwidth request message including an upstream bandwidth from at least one MS for a predetermined time period, detects the requested upstream bandwidth from the upstream bandwidth request message, calculates a total requested upstream bandwidth by summing the requested upstream bandwidth from the at least one MS, generates a new upstream bandwidth request message including the total requested upstream bandwidth, and sends the new upstream bandwidth request message to a BS.

Abstract: A CID management method and apparatus in a multi-hop relay BWA communication system are provided. A BS combines data destined for an RS and data to be relayed to an MS via the RS in a payload, distinguishing the data by CIDs, attaches a relay CID to the payload, and sends the payload with the relay CID to the RS. Among the data of the payload, the RS processes its data and relays to the MS the data destined for the MS by distinguishing them by the CIDs.

Abstract: An apparatus and method for transparently relaying a signal using a plurality of frequency bands in a multi-hop relay cellular network are provided, in which a Relay Station (RS) communicates with a Base Station (BS) via a relay link in a first frequency band and communicates with a Mobile Station (MS) within the sub-cell of the RS via a sub-cell link in a second frequency band different from the first frequency band.

Abstract: An apparatus and method are disclosed for providing location-based advertisement information in a BWA communication system, in which a shop terminal provides advertisement information to a service provider server. The service provider server uses the advertisement information as accounting information and provides path guidance information to a user terminal. A Radio Access Station (“RAS”) broadcasts or selectively sends the advertisement information to the user terminal and sends path guidance approval information received from the user terminal to the service provider server. The user terminal receives the advertisement information from the RAS, sends the path guidance approval information according to user selection, receives the path guidance information from the service provider server, and invokes a path guidance function.

Abstract: A base station having at least one reception antenna generates a reception beam using a previous reception beam weight and a despread signal of a current reception signal, calculates an error value indicating a difference between the current reception signal and a desired reception signal, and calculates a current reception beam weight using the previous reception beam weight, the despread signal and the error value. The base station generates a reception beam weight step value using the error value and an output signal, calculates a difference between the previous reception beam weight and a product of the reception beam weight step value, the despread signal, and a conjugate value of the error value, as the current reception beam weight, and selects the reception beam weight step value such that the current reception beam weight becomes the optimal reception beam.