Abstract: A method is provided for performing handoff in a communication system including a serving base station (BS) in communication with a mobile station (MS), at least one neighbor BS using a communication scheme different from a communication scheme of the serving BS, and the MS capable of communicating with the neighbor BS. The method includes compensating a signal strength of one of the serving BS and the neighbor BS, received at the MS, such that handoff decision is possible, and determining whether to perform a handoff of the MS, using the compensated signal strengths.

Abstract: Provided are an apparatus and a method for providing a concurrent data service to an Mobile Station (MS) through a plurality of heterogeneous networks. In a method for providing a data service to an MS through different wireless networks, the MS measures channel qualities of at least one accessible wireless network and reports the measured channel qualities to an Internet Protocol (IP) packet controller. The IP packet controller selects wireless networks for data transmission on the basis of the reported channel qualities, distributes data destined for the MS, and transmits the distributed data to the selected wireless networks. The selected wireless networks receive the data from the IP packet controller and transmits the received data to the MS. The MS combines and interprets the data received from the selected wireless networks. Accordingly, it is possible to provide a seamless data service to the MS in service environments with a mixture of different wireless communication systems.

Abstract: An apparatus and method for reducing MAP channel overhead in a broadband wireless communication system. In a Base Station (BS), a traffic classifier classifies transmission data into a first group and a second group according to user channel information and packet sizes of the transmission data. A MAP channel configure configures a MAP channel to include information about users of the first group and positions of data for the users, information indicating whether users of the second group have succeeded in random access in a second uplink data region of a previous frame, and information about resource reservation for a current frame for the second group. A channel mapper maps the first group to a first downlink data region and maps the second group to a second downlink data region according to the MAP channel.

Abstract: A method is provided for transmitting/receiving data in a communication system. The method includes measuring, by a Mobile Station (MS), states of channels which are allocated in a scheme prearranged with a Base Station (BS), and encoding measured channel state information in a scheme corresponding to an allocation scheme of the allocated channels; and configuring a message including the encoded channel state information, and transmitting the configured message to the BS.

Abstract: A frame configuration method and apparatus for sending data via an RS in a broadband wireless communication system are provided. In the reception mode, the RS monitors reception of data in an (n?1)th frame from an MS and reception of data in an nth frame from a BS. The RS classifies the data received from the MS and the data received from the BS as combinable data to be sent in combination or as non-combinable data to be sent separately, and stores the classified data distinguishably. When the RS transitions to a transmission mode, it determines whether to XOR-operate or mask the stored data. If the stored data can be masked, the RS XOR-operates the stored data and sends the masked data to the BS and the MS.

Abstract: Provided are an apparatus and method for transmitting/receiving a pilot code pattern used to identify a base station. In the base station, a pilot code pattern determiner determines a code set that includes a number of spreading codes based on a specific ID of the base station. A first spreader spreads a pilot symbol mapped onto an FC with a corresponding spreading code according to the determined code set, and controls gain so as to transmit the pilot symbol at a higher signal level than data. A second spreader spreads data symbols mapped onto the FC with spreading codes of the code set except for the spreading code used for the pilot spreading. A mapper groups a spread signal from the first spreader and spread signals from the second spreader on a TFC basis, and outputs signals that constitute each TFC to points of sub-carriers. An IFFT unit performs an IFFT operation on signals output from the mapper. Because the pilot as well as the data is spread, it is easy to implement the base station.

Abstract: A frame communication apparatus and method for a broadband wireless communication system are provided that employ a transmitter. In the transmitter, a control channel generating unit generates burst allocation information including a receiver identification (ID) with respect to a transmission packet, a burst generating unit constructs data burst by adding a header including a traffic ID to the transmission packet, and a transmitting unit transmits the burst allocation information and the data burst. An existing connection ID (CID) is subdivided into a user ID (UID) and a traffic ID (TID). The UID and the TID are recorded in a map channel message and a medium access control (MAC) header, respectively. Accordingly, an amount of information contained in a downlink map (DL-MAP) and uplink map (UL-MAP), and an amount of the MAC header of a data packet can be reduced.

Abstract: An apparatus and method for transmitting a reference signal in an Orthogonal Frequency Division Multiple Access (OFDMA) communication system in which a total frequency band is divided into a plurality of subcarrier bands. A time division multiplexer performs time division multiplexing such that the reference signal is transmitted for a first duration in a predetermined number of subcarrier bands from among the plurality of the subcarrier bands, and a signal other than the reference signal is transmitted for a second duration other than the first duration. A transmitter transmits the time-division multiplexed subcarrier band signals.

Abstract: A mobile communication system and method utilizing Orthogonal Frequency Division Multiplexing (OFDM) receives channel quality information (CQIs) for subcarriers through which reference signals are transmitted and subcarriers through which data signals are transmitted, in subbands, each including a predetermined number of subcarriers among a plurality of the subcarriers. The CQIs are received from respective receivers. Resources are dynamically assigned to the respective receivers according to the feedback CQIs, thereby enabling dynamic resource assignment with minimized signaling overhead.

Abstract: Disclosed are a method and a system for transmitting/receiving signals in a mobile communication system using a multiple input multiple output adaptive antenna array scheme. A first receiver calculates a reception weight value by using a de-spread signal of a reception signal for creating a reception beam of the first receiver and calculates a transmission weight value by using the calculated reception weight value for creating a transmission beam of the second transmitter, thereby creating feedback information including the transmission weight value. A first transmitter transmits the feedback information to a second receiver. The second receiver receives the feedback information and the second transmitter detects the transmission weight value from the feedback information received in the second receiver, and creates the transmission beam corresponding to the detected transmission weight value in order to transmit a signal by applying the transmission beam to the signal.

Abstract: A method for receiving a signal from a radio unit in a base station having at least one reception antenna is disclosed. The method includes receiving a reception signal via the reception antenna, and generating an output signal using the reception signal and a reception beam weight for a previous time; calculating a cost function using a desired reception signal transmitted from the radio unit among the reception signal and the generated output signal; calculating a trace vector using the calculated cost function and the reception signal; updating the reception beam weight using the trace vector for a next time; and generating a reception beam by applying the updated reception beam weight.

Abstract: An apparatus and method for generating an octal code for identifying cells in a mobile communication system. In the octal code generating apparatus, a binary code generator generates a binary code with a predetermined minimum Hamming distance. A column permutator permutes the order of columns of the binary code in a predetermined interleaving method. A 3-bit combiner generates a plurality of codewords using the column-permuted binary code as a generator matrix and groups the bits of each of the codewords by threes. An octal code generator converts the 3-bit grouped binary codewords to octal code sequences.

Abstract: An apparatus and method for transmitting/receiving a pilot pattern set to distinguish a base station in an FDM communication system. The method divides a total frequency bandwidth into at least two sub-bandwidths including a plurality of sub-carriers in an OFDMA (Orthogonal Frequency Division Multiple Access) mobile communication system, configures a single frame cell (FC) using one sub-bandwidth from among the sub-bandwidths and a plurality of OFDM (Orthogonal Frequency Division Multiplexing) symbol intervals, and assigns a pilot signal to a time-frequency cell comprised of at least one OFDM symbol and at least one sub-carrier within the FC. The method includes the steps of spreading a pilot signal and a data signal using different orthogonal codes, synthesizing the spread pilot and data signals, and performing a CDM (Code Division Multiplexing) process; and mapping the CDM-processed pilot and data signals to a predetermined time-frequency cell in the FC.

Abstract: A transceiver system and method in an OFDM communication system which enables exact symbol synchronization acquisition and improves performance for frequency offset and channel estimation. In the apparatus, a guard interval filling unit copies data at a predetermined interval in an input data row inputted to be transmitted, and fills in the copied data in the preset guard interval in the input data row. A selection unit selectively receives an output data row outputted from the guard interval filling means and unique words having a constant amplitude and a non-periodic auto-correlation characteristic, and outputs the OFDM symbol in which the unique words are inserted in the output data row.

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-2×M×N preamble sequence, where 2×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 2×M×N subcarriers among the A subcarriers on a one-to-one mapping basis, assigning null data to the remaining subcarriers excluding the 2×M×N subcarriers from the A subcarriers, and then IFFT-transforming the assigned result into time-domain data.

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: A method is provided for transmitting/receiving data in a communication system. The method includes measuring, by a Mobile Station (MS), states of channels which are allocated in a scheme prearranged with a Base Station (BS), and encoding measured channel state information in a scheme corresponding to an allocation scheme of the allocated channels; and configuring a message including the encoded channel state information, and transmitting the configured message to the BS.

Abstract: An apparatus and method for reducing MAP channel overhead in a broadband wireless communication system. In a Base Station (BS), a traffic classifier classifies transmission data into a first group and a second group according to user channel information and packet sizes of the transmission data. A MAP channel configure configures a MAP channel to include information about users of the first group and positions of data for the users, information indicating whether users of the second group have succeeded in random access in a second uplink data region of a previous frame, and information about resource reservation for a current frame for the second group. A channel mapper maps the first group to a first downlink data region and maps the second group to a second downlink data region according to the MAP channel.

Abstract: Provided are an apparatus and a method for providing a concurrent data service to an Mobile Station (MS) through a plurality of heterogeneous networks. In a method for providing a data service to an MS through different wireless networks, the MS measures channel qualities of at least one accessible wireless network and reports the measured channel qualities to an Internet Protocol (IP) packet controller. The IP packet controller selects wireless networks for data transmission on the basis of the reported channel qualities, distributes data destined for the MS, and transmits the distributed data to the selected wireless networks. The selected wireless networks receive the data from the IP packet controller and transmits the received data to the MS. The MS combines and interprets the data received from the selected wireless networks. Accordingly, it is possible to provide a seamless data service to the MS in service environments with a mixture of different wireless communication systems.