Abstract:
Disclosed is an apparatus and method for adaptively allocating transmission power for beamforming combined with orthogonal space-time block codes (OSTBC) in a distributed wireless communication system, the apparatus comprising: a plurality of sub-arrays for beamforming, which are geographically distributed and each of which comprises a plurality of distributed antennas placed in random groups; and a central processing unit for identifying performances of subsets by applying a predetermined power allocation scheme according to subsets which can be obtained by combining the sub-arrays, by means of a Nakagami fading parameter and information about large-scale fading of each of the sub-arrays, fed back from a receiving party, for determining a subset having a best performance as an optimal subset according to the identified performances, and for performing power allocation based on the subset set as the optimal subset.
Abstract:
A method provides mixed analog/digital beamforming by a transmitter in a mobile communication system. The method includes converting a modulation symbol into a parallel symbol stream, performing digital beamforming on the parallel symbol stream, performing an IFFT operation on the digital-beamformed parallel symbol stream to generate a time-domain symbol, converting the IFFT-operated time-domain symbol into a serial time-domain symbol, inserting a CP into the serial time-domain symbol, performing a DAC operation on the CP-inserted symbol to generate an analog signal, and performing analog beamforming by multiplying the analog signal by the analog beamforming precoder optimized for the first subcarrier transmitted through at least one RF channel.
Abstract:
Provided is a device and a method for eliminating inter-cell interference in Multiple Input Multiple Output (MIMO) wireless communication system. The method for operating a user equipment for eliminating the inter-cell interference includes determining one or more optimum bands among bands not requested to be restricted from a neighboring cell, determining at least one of band and Precoding Matrix Index (PMI) to be requested to be restricted to the neighboring cell among the determined one or more optimum bands, and feeding back at least one of the band and PMI to be requested to be restricted to the neighboring cell to a serving base station.
Abstract:
A Mobile Station (MS) apparatus and a Base Station (BS) apparatus, and methods for their operation in a wireless communication system, are provided. The method for operating the MS includes receiving Precoding Matrix Index (PMI) subset information from a BS, determining downlink channel quality of the BS, determining a PMI for the BS based on the PMI subset information and the determined downlink channel quality of the BS, and transmitting the determined PMI to the BS.
Abstract:
A multiple antenna system including a mobile station and a base station are operable to perform a method for transmitting control information for interference mitigation. A Mobile Station (MS) can transmit control information for interference mitigation. The MS determines a first Precoding Matrix Index (PMI) and a second PMI for interference from an adjacent Base Station (BS). Based on a correlation level from correlation values between one of the first PMI and second PMI and the remaining PMIs in the codebook, the MS determines a level of a subset of PMIs, and feeds back information indicating the correlation level.
Abstract:
Disclosed is a system and a method for performing handover in a Worldwide interoperability for Microwave Access (WiMAX) mobile communication system supporting broadband wireless access. The system includes a plurality of Mobile Stations (MSs); at least one distributed antenna having the ability to perform simultaneous communications with the plurality of MSs; and a base station connected to the at least one distributed antenna through optical fibers for performing communications and handovers with the multiple MSs.
Abstract:
A method and apparatus reduce overhead of feedback in a closed loop Multiple Input Multiple Output (MIMO) system. A controller feeds back the long-term Precoder Matrix Index (PMI) to a serving base station under direction of the serving base station when the long term PMI feedback transmission is required, generates a new codebook using the long term PMI, and determines a short term PMI from the new codebook. A feedback transmitter feeds back the short-term PMI to the serving base station.
Abstract:
A calibration apparatus and a calibration method for multicell Multiple Input Multiple Output (MIMO) transmission in a multiple antenna system are provided. More particularly, an operating method of a Mobile Station (MS) for performing calibration for multicell MIMO transmission in a multiple antenna system includes negotiating a multi-Base Station (BS) joint processing with a BS, receiving a control message including information instructing multi-BS calibration for sounding based on the multi-BS joint processing, from the BS; when receiving the control message involving the multi-BS joint processing, generating a second sounding sequence by mapping estimated phases of downlink channels per subcarrier of BSs to a first sounding sequence allocated from the BS, and transmitting the second sounding sequence, including the phases of the downlink channels per subcarrier, over a sounding symbol interval with respect to each of the BSs involving the multi-BS joint processing. Hence, feedback overhead in the calibration of the multicell MIMO transmission can be reduced.
Abstract:
A method and apparatus for transmitting and receiving a signal in a Near Field Communication (NFC) system are provided, in which a multi-frame is configured and a signal is transmitted in the multi-frame to a reception terminal The multi-frame includes a discovery region, a paging region, at least two scheduling regions for indicating a plurality of different scheduling algorithms, and a traffic slot region. A transmission terminal transmits a signal for searching for a neighbor terminal in the discovery region, transmits a paging signal in the paging region, transmits information for a scheduling algorithm that is predetermined by the transmission terminal and the reception terminal in each of the scheduling regions, and transmits a scheduled signal in the traffic slot region according to the predetermined scheduling algorithm.
Abstract:
An apparatus and method for initial ranging in a wireless communication system including a heterogeneous network. An operation of a terminal includes selecting a serving cell considering a biased value of a base station applying range expansion. The operation also includes receiving ranging code classification information and threshold information associated with the serving cell. The operation further includes, if a channel quality with the serving cell is less than the threshold, selecting one a plurality of poor-expected-ranging codes indicated by the ranging code classification information, and performing initial ranging using the selected poor-expected-ranging code.