Abstract: An Iterafive Detection and Decoding (IDD) receiving apparatus and method in a multiple input multiple output (MIMO) communication system. The IDD receiving apparatus includes an MIMO detector which generates soft decision values of coded bits by MIMO-decoding a receive vector, feedback priori information, and a list of candidate coded symbol vectors; a decoder which Soft-Input/Soft-Output (SISO)-decodes the soft decision values generated at the MIMO detector and feeds back soft decision values of the coded bits to the MIMO detector; a hard decision part which generates a coded symbol vector by performing a hard decision on the soft decision values generated at the decoder; and a list updater which generates a list of candidate coded symbol vectors using the receive vector and provides the list to the MIMO detector at a first iteration, updates the list using the coded symbol vector fed from the hard decision part, and provides the updated list to the MIMO detector at subsequent iterations.

Abstract: A Log-Likelihood Ratio (LLR) generating apparatus and method in a communication system using a spatial multiplexing scheme. The reception method includes acquiring at least one estimated transmit vector by demodulating a receive vector using at least one Multiple Input Multiple Output (MIMO) detection process; selecting one of the at least one estimated transmit vector as an optimum estimated transmit vector; calculating LLRs with respect to the optimum estimated transmit vector; calculating a weight to be applied to each of elements constructing the optimum estimated transmit vector; and applying the weight to each of the calculated LLRs. Accordingly, the present invention can generate the LLRs with high reliability similar to the LLRs of a Maximum Likelihood receiver by applying the weight to the LLRs generated from the estimated transmit vector.

Abstract: A scheduling apparatus and method in a smart antenna system including a user where an active nulling is to be conducted are provided, in which at least one user is selected where a normal beamforming is conducted corresponding to a certain criterion; an active nulling user comprising a low channel correlation with the selected beamforming user is selected from users where an active nulling is conducted; and the normal beamforming for the selected beamforming user and the active nulling beamforming for the selected active nulling user are determined. In the system where the normal beamforming user and the active nulling user are mingled, the criterion to select the users that do not interfere with one another is suggested for the same resource to thereby efficiently utilize the resource.

Abstract: A traffic channel transmission device for a CDMA communication system using a plurality of coding rates and orthogonal codes, determines a present channel condition and adaptively selects a coding rate and an orthogonal code according to the determination. In the device, a channel receiver receives a channel signal and a controller analyzes the received signal to decide an environment of a channel in service and generates a coding rate select signal and orthogonal code information according to the decision result. A channel transmitter includes a channel encoder for encoding transmission data at a coding rate selected according to the coding rate select signal and an orthogonal modulator for generating an orthogonal code according to the orthogonal code information to spread the encoded data with the generated orthogonal code, whereby the channel transmitter adaptively encodes and spreads the transmission data according to the channel environment.

Abstract: The present invention is provided a method for allocating uplink resources in a communication system. The method includes calculating a scheduling metric for each Mobile Station (MS), selecting an MS with a high priority according to the scheduling metric, determining a Modulation order Product coding Rate (MPR) and a number of subchannels for the selected MS, and allocating the determined MPR and the determined number of subchannels to the selected MS and updating the scheduling metric for the each MS.

Abstract: Provided are an ARQ apparatus and method for a multihop system in a broadband wireless access communication system. The ARQ method of a relay includes determining if the relay successfully receives specific data from a source and transmitting the specific data to a destination; receiving feedback data from the destination and determining if the destination successfully receives the specific data; generating feedback data including data indicating if the relay and the destination successfully receive the specific data, and outputting the feedback data to the source; and retransmitting the specific data, when the relay successfully receives the specific data but the destination fails to receive the specific data. Accordingly, when the MH-BTS successfully receives the data from the source but the destination fails to receive the data, the source does not retransmit same data to the MH-BTS.

Abstract: Provided are an Automatic ReQuest (ARQ) apparatus and method for a multihop system in a broadband wireless access communication system. When the number of ACK MAPs in ARQ feedback information element of ARQ feedback message transmitted from a destination or Multi-Hop Base Transceiver Station (MH-BTS) is not zero, and it is determined that the destination or a lower MH-BTS successfully receives data corresponding to Block Sequence Number (BSN), the BSN is updated with a BSN successfully received at the destination or the lower MH-BTS, and is transmitted to the upper MH-BTS or the source. Accordingly, when the MH-BTS successfully receives the data from the source but the destination fails to receive the data, the source does not retransmit same data to the MH-BTS.

Abstract: An uplink scheduling apparatus and method in a communication system are provided. In the uplink scheduling method, a scheduling metric is calculated for each Mobile Station (MS). An MS with a high priority level is selected according to the calculated scheduling metric. The number of subchannels and a product of a modulation order and coding rate (MPR) are extracted according to input variables for the selected MS. The number of subchannels to be allocated to the selected MS is determined according to the MPR and the subchannels are allocated to the selected MS. The scheduling metric is updated for the each MS.

Abstract: In a communication system, a first Downlink (DL) signal to be commonly received by all Mobile Stations (MSs) at a Base Station (BS) is generated. A second DL signal that all the MSs do not need to commonly receive is generated. The first DL signal is applied to an interference cancellation scheme. The first DL signal is transmitted in a first time interval. The second DL signal is transmitted in a second time interval.

Abstract: A handover apparatus and method for a multi-hop system in a BWA communication network are provided. In a handover system supporting multi-hop system in a BWA communication network, a BS periodically broadcasts a message with neighboring BS/RS information. When a new BS or RS needs to be added, an RS periodically broadcasts the broadcast message received from the BS with information about the new BS or RS. An MS receives the broadcast message from the RS and requests information about BSs or RSs to which the MS can perform a handover by notifying candidate BSs or RSs for the handover. The candidate BSs or RSs may include a BS or RS not included in the broadcast message, if the MS detects the BS or RS by scanning. The MS selects a target BS or RS based on the BS or RS information received from the BS, and performs the handover to the target BS or RS.

Abstract: Provided is a multi-hop wireless mobile communication system where a plurality of nodes exist. To select a serving node to be provided with a service, a Mobile Station (MS) receives relay information provided for serving node selection from at least two nodes and selects a first mode of selecting a node that requires the minimum time for unit data transmission/reception as the serving node or a second mode of selecting a node that can transmit and receive the maximum data per unit time as the serving node, based on the received relay information, in order to select the serving node.

Abstract: An apparatus and method for improving the reception performance of a Mobile Station (MS) in a multiple antenna system are provided. In an apparatus of a Base Station (BS) in the multiple antenna system, upon receipt of a request for interference cancellation for a first MS serviced by a neighbor BS, a channel estimator estimates a channel from the first MS and a channel from a second MS serviced by the BS. A beam coefficient generator generates a first beam coefficient based on channel estimates of the first and second MSs and a second beam coefficient based on the channel estimate of the second MS. An interference cancellation decider determines whether to perform interference cancellation for the first MS using the first and second beam coefficients.

Abstract: A method is provided for controlling uplink power in a wireless communication system. The method includes receiving downlink channel information from a mobile station (MS); measuring uplink channel information of the MS; selecting channel information having a lower value from among the forward channel information and the uplink channel information; determining a power level and a Modulation and Coding Scheme (MCS) level for the MS using the selected channel information; and transmitting the determined power level and MCS level to the MS.

Abstract: A method is provided for transmitting and receiving data in a multi-hop wireless mobile communication system having a first mobile station (MS), a second MS, a base transceiver station (BTS), and a relay BTS. The method includes allowing the first MS to directly communicate with the BTS, and allowing the second MS to communicate with the BTS by relay of the relay BTS; performing communication between the BTS and the first MS and communication between the relay BTS and the second MS using a first frame; and performing communication between the BTS and the relay BTS using a second frame.

Abstract: A method and apparatus for supporting a seamless handover in a transport layer is provided. In a network using an SCTP, an MN notifies a CN of a handover after the handover occurs. The MN receives a handover confirm message from the CN and sends a response message for the handover confirm message to the CN. The MN checks a recipient IP address at which data is received from the CN. If the recipient IP address is a new IP address, the MN changes a primary IP address of the MN to the new IP address. If the recipient IP address is the primary IP address, the MN maintains the primary IP address.

Abstract: A method and apparatus of supporting a fast handover in a transport layer is provided. In a network using an SCTP (Stream Control Transmission Protocol), an MN (Mobile Node) acquires a first new IP (Internet Protocol) address after a first handover to a first new network area, stores information about the first handover to the first new network area, and sends (i.e., transmits) a first handover message including the new IP address to a CN (Correspondent Node). If a second handover to a second network area is required, the MN performs the second handover even if a response message for the first handover message has not been received, acquires a second new IP address, stores information about the second handover, and sends a second handover message including the second new IP address to the CN.

Abstract: A transmitter and a transmitting method for forming a pseudo common beam using a plurality of antennas in a smart antenna communication system are provided, in which beams for tones of Orthogonal Frequency Division Multiplexing (OFDM) signals transmitted through a plurality of antennas are rotated at different phases around a frequency axis, such that a combined beam of the transmitted beams is equivalent to a pseudo common beam. Accordingly, a peak to average power ratio (PAPR) of the preamble signal is prevented from changing.

Abstract: Disclosed are a handoff system and a handoff method in a communication system with a smart antenna. In a method for performing handoff in a communication system including BSs which have different antenna structures, neighbor BS information including antennas structure information of neighbor BSs is received from a serving BS, a handoff threshold value is set according to the received neighbor BS information, and a difference between pilot strengths of the neighbor BSs and that of the serving BS is compared with the set handoff threshold value to thereby determine whether to perform the handoff.

Abstract: Apparatus and method for simultaneously selecting two cells in a broadband cellular communication system with a frequency reuse factor of N. Adjacent cells are searched and the RX power strengths of the adjacent cells are measured. Cells with RX power strengths greater than a predetermined value are selected among the adjacent cells. Two cells are selected among the selected cells and the FAs and RX power strengths of the two cells are compared. If the two cells have adjacent FAs and/or similar RX power strengths, the two cell are selected to perform communication. The apparatus and method simultaneously receives data signals from two cells with adjacent FAs in a cellular environment with a frequency reuse factor of N, by sharing the adjacent FAs.

Abstract: Provided are an apparatus and a method for performing a handoff in a broadband cellular communication system with a frequency reuse factor of N by using both of two neighboring frequency allocations. The method includes determining, if a mobile station receives a signal from a second base station during communication with a second base station, whether frequency allocations of the two base stations are adjacent to each other, measuring and comparing signal strengths of the two base stations if the frequency allocations are adjacent to each other, sending a handoff request to the first base station if the signal strength of the first base station is less than or equal to the signal strength of the second base station, and simultaneously receiving signals of the two frequency allocations by simultaneously allocating portions of the frequency allocations to the mobile station according to the handoff request.