Abstract: A method compensates for a frequency error in a communications system. The method includes detecting a received preamble sequence in a received signal. The received preamble sequence is detected based on a plurality of power estimates corresponding to a plurality of frequency bins of a received frequency domain signal and a plurality of relative phase errors corresponding to the plurality of frequency bins of the received frequency domain signal. The method includes determining the frequency error using the received preamble sequence. The method includes adjusting the receiver based on the frequency error.

Abstract: In a wireless communication base station device, a modulation unit carries out modulation processing for Dch data after coding to generate a Dch data symbol. A modulation unit carries out modulation processing for Lch data after coding to generate an Lch data symbol. An allocation unit allocates the Dch data symbol and Lch data symbol to each sub-carrier composing an OFDM symbol and outputs the allocated sub-carrier to a multiplex unit. In this case, the allocation unit allocates the Dch data symbol to a plurality of resource blocks where one Dch is arranged at an interval equal to integral multiples of the number of resource blocks composing a resource block group.

Abstract: Embodiments of the present invention disclose a precoding matrix indicator feedback method, receiving method, and apparatus. User equipment UE receives a reference signal sent by a base station; the UE selects, based on the reference signal, a precoding matrix for each first subband of N first subbands in a system transmission bandwidth from a codebook, where the codebook includes at least two precoding matrixes, and each precoding matrix is denoted by at least a first precoding matrix indicator PMI and a second PMI, where each first subband of the N first subbands corresponds to a second PMI, and each second subband of M second subbands corresponds to a first PMI; and the UE feeds back the first PMI corresponding to each second subband to the base station, and feeds back the second PMI corresponding to each first subband to the base station.

Abstract: A wireless device receives messages indicating CSI measurement resources of cells belonging to at least two base stations or belonging to at least two sectors of a base station. The wireless device measures CSI employing at least CSI measurement resources of the cells. The wireless device quantizes the measured CSI jointly across cells and encodes and transmits the jointly quantized CSI. The wireless device receives a resource assignment for data packet(s). The wireless device receives signals carrying the data packets from multiple cells.

Abstract: A bit interleaver, a bit-interleaved coded modulation (BICM) device and a bit interleaving method are disclosed herein. The bit interleaver includes a first memory, a processor, and a second memory. The first memory stores a low-density parity check (LDPC) codeword having a length of 64800 and a code rate of 3/15. The processor generates an interleaved codeword by interleaving the LDPC codeword on a bit group basis. The size of the bit group corresponds to a parallel factor of the LDPC codeword. The second memory provides the interleaved codeword to a modulator for 4096-symbol mapping.

Abstract: A method of generating a reference signal includes acquiring a base sequence and acquiring a reference signal sequence with a length N from the base sequence. Good PAPR/CM characteristics of the reference signal can be kept to enhance performance of data demodulation or uplink scheduling.

Abstract: A disclosure of the present specification provides a method for transmitting a sounding reference signal (SRS) by a terminal. The method may include the steps of: receiving an SRS configuration from a base station by the terminal; on the basis of the received SRS configuration, determining an SRS sub-frame to which an SRS is to be transmitted among a plurality of sub-frames, and an SRS transmission region to which an SRS is to be transmitted in a physical uplink control channel (PUCCH) region on the SRS sub-frame; and transmitting the SRS to the SRS transmission region on the determined SRS sub-frame, wherein when the SRS and a PUCCH are transmitted simultaneously to the SRS transmission region, the SRS and the PUCCH may be multiplexed on the basis of code division multiplexing (CDM).

Abstract: A method for a base station processing in-band multiplexing using an FCP-OFDM scheme may comprise the steps of: transmitting, to a terminal, information on the length of zero padding (ZP) for a receiving side and the length of ZP for a transmitting side in a band for a first service among one or more services provided in one carrier; and on the basis of the information on the length of ZP for a receiving side and the length of ZP for a transmitting side, processing a signal of the first service in the transmitting end or receiving end of the base station.

Abstract: A spur cancelation system includes error circuitry, inverse spur circuitry, and injection circuitry. The error circuitry is configured to generate an error signal based at least on a first transceiver signal in a transceiver signal processing chain. The inverse spur circuitry is configured to, based at least on the error signal, determine a gain and a phase of a spur signal in the transceiver signal and generate an inverse spur signal based at least on the gain and the phase of the spur signal. The injection circuitry is configured to inject the inverse spur signal to cancel a spur in a second transceiver signal in the transceiver signal processing chain.

Abstract: The embodiments disclose a method in an AP for downlink transmission in a beamforming radio communication network. The method comprises grouping a plurality of terminal devices to be scheduled for downlink transmission into one or more groups; and associating each of the one or more groups with a different one of digital chains in the AP, wherein payloads to be transmitted to terminal devices in a same group are processed by a digital chain associated with the group.

Abstract: A communications system has a cellular structure including a base station that is located within a cell of the cellular structure and provides an elevation beamforming transmission based on a set of elevation precoding matrix indicator offsets in an elevation codebook. The communications system also includes user equipment that is located within the cell and coupled to the base station to receive the set of elevation precoding matrix indicator offsets and a set of reference signals to provide channel quality and inter-cell interference measurements, wherein a selected channel quality indicator is based on an increase in channel quality with respect to inter-cell interference at the user equipment and corresponds to one of the set of elevation precoding matrix indicator offsets. A method of operating a communications system having a cellular structure is also provided.

Abstract: A method and system for allocating shareable wireless transmission resources. A resource pool is established. The resource pool is divided into a plurality of physical layer allocation units usable for wirelessly transmitting control information and traffic data. The allocation units are assigned at the media access control layer for the wireless transmission of the control information and traffic data. The system and method of the present invention also allows mobile stations to be dynamically grouped into multicast groupings to reduce system overhead resource requirements.

Abstract: A cable modem termination system (CMTS) may communicate with a plurality of cable modems using a plurality of orthogonal frequency division multiplexed (OFDM) subcarriers. The CMTS may determine a performance metric of each of the cable modems. For each of the OFDM subcarriers and each of the cable modems, the CMTS may select physical layer parameters to be used for communication with that cable modem on that OFDM subcarrier based on a performance metric of that cable modem. The parameters may be selected for each individual modem and/or each individual subcarrier, or may be selected for groups of modems and/or groups of subcarriers. The parameters may include, for example, one or more of: transmit power, receive sensitivity, timeslot duration, modulation type, modulation order, forward error correction (FEC) type, and FEC code rate.

Abstract: A method of indicating to a secondary station a set of at least one available transmission resource among a predetermined plurality of transmission resources, each set being described by a plurality of parameters, said method comprising the steps of: —signalling to the secondary station an association between a control signalling channel and at least one parameter describing a set of transmission resources; coding into an address at least one remaining parameter from the plurality of parameters describing the said set of transmission resources; —transmitting the address to the secondary station using the said control signalling channel.

Abstract: Methods (500, 800) and corresponding systems (100, 200, 300, 400, 900) for generating a pilot symbol (330) include providing an M-point parallel transform sequence that is a discrete Fourier transform of a CAZAC sequence (312, 504-508). The M-point parallel transform sequence (312) is distributed (316, 510) to a set of M subcarriers among N subcarriers to form an N-point frequency-domain sequence (318) wherein the M subcarriers are evenly spaced apart. An N-point inverse fast Fourier transform (320, 512) is performed to convert the N-point frequency-domain sequence to an N-point time-domain sequence (322). The N-point time-domain sequence is converted (324, 514) to a serial sequence (326), and a cyclic prefix is added (328, 516) to the serial sequence to form a pilot symbol (330).

Abstract: The teachings herein present a method and apparatus that implement and use a factorized precoder structure that is advantageous in terms of performance and efficiency. In particular, the teachings presented herein disclose an underlying precoder structure that allows for certain codebook reuse across different transmission scenarios, including for transmission from a single Uniform Linear Array (ULA) of transmit antennas and transmission from cross-polarized subgroups of such antennas. According to this structure, an overall precoder is constructed from a conversion precoder and a tuning precoder. The conversion precoder includes antenna-subgroup precoders of size NT/2, where NT represents the number of overall antenna ports considered. Correspondingly, the tuning precoder controls the offset of beam phases between the antenna-subgroup precoders, allowing the conversion precoder to be used with cross-polarized arrays of NT/2 antenna elements and with co-polarized arrays of NT antenna elements.

Abstract: An orthogonal frequency division multiplexing (OFDM) signal transmission apparatus which transmits OFDM signals by using a plurality of transmission antennas includes a subcarrier setting device which sets signals for subcarriers so as to use some of the subcarriers of the OFDM signals as pilot subcarriers to transmit pilot signals and use the remaining subcarriers as data subcarriers to transmit data signals, the subcarrier setting device changing polarities of signals for the pilot subcarriers for each transmission antenna.

Abstract: The present invention relates to a method for transmitting uplink control information in a mobile communication system; and, more particularly, to a method for effectively forming uplink control information transmitted through a downlink from a base station to a terminal in a mobile communication system for providing a packet service and transmitting the uplink control information with minimum radio resources occupied. The method includes the steps of generating uplink control information; allocating the uplink control information to a downlink-shared radio resource for packet data transmission based on downlink scheduling information; and transmitting the radio resource to a terminal. The present invention is applied to a mobile communication system.

Abstract: A transmission apparatus includes processing circuitry that generates a first data sequence representing first data or a second data sequence representing second data different from the first data and selects the first data sequence as an output data sequence. A modulation scheme is determined from a plurality of modulation schemes, and the output data sequence is modulated with the determined modulation scheme. Transmission circuitry transmits the modulated output data sequence. A first time interval associated with selecting the first data sequence for the output data sequence is longer than a second time interval associated with determining the determined modulation scheme.

Abstract: A method is provided for transmitting broadcast signals. Service data is encoded. The encoded service data is mapped to symbols onto constellations. Data cells are frequency interleaved in a symbol among the symbols in at least one frame unit using an interleaving sequence. The interleaving sequence is generated based on a main interleaving-sequence and a symbol offset value. The interleaving sequence is generated by operating the main interleaving-sequence with the symbol offset value. The data cells are included in the symbol with a symbol index and a frame unit with a frame unit index. The frequency interleaving of the data cells operates on a frame basis. The frequency interleaving of the data cells is reset when a first frame unit is changed to a second frame unit. Data is modulated in the at least one frame unit by an Orthogonal Frequency Division Multiplexing (OFDM) scheme. The broadcast signals carrying the modulated data are transmitted.

Abstract: A signal transmission method for reducing inter-cell interference according to the present invention may comprise the steps of: determining a rank on the basis of feedback information received from a terminal; generating a transmission sequence according to the rank; generating a repetitive transmission sequence by repeating the transmission sequence, and shifting a position of a symbol within the repetitive transmission sequence; and transmitting the transmission sequence and the repetitive transmission sequence. As a result, the present invention can implement an inter-cell interference randomization even in a closed-loop MINO.

Abstract: An Internet of things (IoT) device random access method based on a massive MIMO technology is disclosed, and a cellular IoT communication system using the random access method is also disclosed. In the method, multiples users access a base station by using the same preamble sequence, the users accessing the base station in different beams respectively. By use of narrow beam characteristics of a massive MIMO technology, users in different beams can use the same preamble sequence for random access, thus greatly reducing collision probability of the random access and greatly increasing the number of users of random access, and congestion and collision problems during random access of a great number of users in the cellular IoT communication system can be effectively solved.

Abstract: An apparatus for transmitting broadcast signal according to the present invention includes an enhanced layer stream partitioner configured to generate first and second enhanced layer partitioned signals by partitioning an enhanced layer stream; first and second combiners configured to generate a first multiplexed signal corresponding to the first enhanced layer partitioned signal and a second multiplexed signal corresponding to the second enhanced layer partitioned signal; first and second power normalizers configured to reduce powers of the first multiplexed signal and the second multiplexed signal; first and second time interleavers configured to generate a first time-interleaved signal corresponding to the first enhanced layer partitioned signal and a second time-interleaved signal corresponding to the second enhanced layer partitioned signal; and first and second OFDM transmitters configured to transmit signals corresponding to the first time-interleaved signal and the second time-interleaved signal using

Abstract: A power line communication (PLC) device is provided which communicates with another PLC device via a PLC signal transmitted over a wire in a broadband. The PLC signal comprises at least one frame. The at least one frame comprises a preamble, a frame control header and a payload. The preamble comprises at least one synchronization symbols used for a PLC engine to synchronize; at least one preamble code symbols used for specifying at least one of a sub-channel and a modulation mechanism; and at least one channel estimation symbols used for the PLC engine to do channel estimation.

Abstract: In a radio using a plurality of channels defined in a radio frequency (RF) spectrum, a rate of false packet detections may be calculated for each of the plurality of channels using a plurality of respective correlation thresholds. The rate of false packet detections for each channel may be compared to a range of acceptable rates of false packet detections. The same or different ranges of acceptable rates of false packet detections may be used for each channel or each channel plan. Different correlation thresholds may be adjusted based at least in part on the comparisons. For example, if a rate of false packet detections exceeds a range of acceptable rates of false packet detections, the correlation threshold may be raised, or the reverse. A packet may be detected on different channels based on different adjusted correlation thresholds.

Abstract: Systems and methods for adjusting timing in a communication system, such as an OFDM system are described. In one implementation an error signal is generated to adjust the timing of a variable rate interpolator so as to adjust FFT timing. The error signal may be based on detection of significant peaks in an estimate of the impulse response of the channel, with the peak locations being tracked over subsequent symbols and the system timing adjusted in response to changes in the peaks.

Abstract: The present specification relates to a method for transmitting medium access control protocol data unit (MAC PDU) in a wireless communication system. The method, which is performed by a terminal, comprises the steps of: transmitting a control signal through a physical uplink channel to a base station; and transmitting the MAC PDU including terminal identifier information for identifying the terminal to the base station using contention resources within contention-based PUSCH zone (CP zone).

Abstract: A method for transmitting data from a station (STA) device in a wireless LAN (WLAN) system, according to one embodiment of the present invention, comprises the steps of: generating a physical protocol data unit (PPDU) including a physical preamble and a data field; and transmitting the PPDU, wherein when the data field is transmitted by using a 106-tone resource unit including first to fourth pilot tones, the positions of the first to the fourth pilot tones may be identical to the positions of four pilot tones from among eight pilot tones included in four 26-tone resource units, which are present at a position corresponding to the 106-tone resource unit, or identical to the positions of four pilot tones from among eight pilot tones included in two 52-tone resource units, which are present at a position corresponding to the 106-tone resource unit.

Abstract: Certain aspects of the present disclosure relate to techniques for determining resource elements REs used for Coordinated Multipoint (CoMP) transmission schemes. The techniques generally include determining, by a User Equipment (UE), a set of data REs used for Coordinated Multipoint (CoMP) operation. The determination is based on a CoMP scheme and data REs available to particular base stations involved in the CoMP operation. The technique further includes processing data received via the CoMP operation on the determined set of data REs.

Abstract: Disclosed are a method for acquiring synchronization in a cable network, and a physical (PHY) transmitter and PHY receiver. The method for acquiring synchronization in a cable network according to an embodiment includes receiving, by a PHY receiver, a signal from a PHY transmitter, and acquiring, by the PHY receiver, channel synchronization when a symbol in which a channel preamble exists is detected from the received signal and a position of a frequency in which a channel subcarrier exists is detected from the detected symbol by performing a cross correlation operation on the received signal and the channel preamble.

Abstract: A method for transmitting control information, performed by a user equipment (UE), in a wireless communication system, the method includes generating, by the UE, uplink control information (UCI); and transmitting, by the UE to a base station, the UCI through a physical uplink control channel (PUCCH) in a subframe, wherein, when the subframe is configured for transmission of a scheduling request (SR) and when transmission of a hybrid automatic repeat request acknowledgement (HARQ-ACK) coincides with the subframe, transmission power of the PUCCH is determined based on a payload size of both the HARQ-ACK and the SR.

Abstract: An orthogonal frequency division multiplexing (OFDM) transmission system is provided which includes a data processing unit which generates a transmission signal using a plurality of tones including a reserved tone, a storage unit which stores Peak Reduction Kernel information according to the type of data symbol, and a compensation unit which retrieves the Peak Reduction Kernel information according to the type of data symbol from the storage unit and causes the retrieved information to be carried by the reserved tone included in the transmission signal. Therefore, a Peak-to-Average Power Ratio (PAPR) can be efficiently compensated.

Abstract: Systems and methods are disclosed for providing efficient downlink Hybrid Automatic Request (HARQ) feedback. In some embodiments, a method of operation of a wireless device in a cellular communications system comprises receiving a downlink control information message comprising a HARQ feedback buffer index and storing a downlink HARQ feedback flag in a position within a HARQ feedback buffer that corresponds to the HARQ feedback buffer index. In this manner, multiple downlink HARQ feedback flags can be stored in the HARQ feedback buffer and subsequently transmitted to a network node in an efficient manner.

Abstract: User equipment (UE)-initiated accesses within a cellular network are optimized to account for cell size and to reduce signaling overhead. A fixed set of preamble parameter configurations for use across a complete range of cell sizes within the cellular network is established and stored within each UE. A UE located in a given cell receives a configuration number transmitted from a nodeB serving the cell, the configuration number being indicative of a size of the cell. The UE selects a preamble parameter configuration from the fixed set of preamble parameter configurations in response to the received configuration number and then transmits a preamble from the UE to the nodeB using the preamble parameter configuration indicated by the configuration number.

Abstract: A communication device determines a format according to which a data unit is to be generated, and selects a pilot sequence to be used for generating the data unit. The pilot sequence is selected from a plurality of pilot sequences corresponding to a plurality of data unit formats, and the pilot sequence is selected based on the determined format. The communication device generates the data unit to include the selected pilot sequence, and transmits the data unit.

Abstract: In a wireless communication base station device, a modulation unit carries out modulation processing for Dch data after coding to generate a Dch data symbol. A modulation unit carries out modulation processing for Lch data after coding to generate an Lch data symbol. An allocation unit allocates the Dch data symbol and Lch data symbol to each sub-carrier composing an OFDM symbol and outputs the allocated sub-carrier to a multiplex unit. In this case, the allocation unit allocates the Dch data symbol to a plurality of resource blocks where one Dch is arranged at an interval equal to integral multiples of the number of resource blocks composing a resource block group.

Abstract: A parallel information processing apparatus includes a group of switches configured to have a topology of a Latin square, and nodes connected with a switch among the group of switches. The parallel information processing apparatus also include a memory and a processor configured to designate (n×k) units of blocks in the group of switches included in a lattice structure in the topology of the Latin square; to generate information about communication protocol that includes communication directions having different slopes for m (m?k) units of the nodes, and the number of hops set for the respective communication directions having the different slopes; and to execute communication for the m units of the nodes of the units of the block, based on the information about communication protocol, so as to execute part-to-part communication between the m units of the nodes of the respective units of the blocks.

Abstract: In the conventional technique, only an output having a bandwidth identical to the bandwidth of individual DACs has been obtained even by using a plurality of DACs. Also, even when the output of a bandwidth broader than the individual DAC is obtained, there has been a problem associated with asymmetricity of a circuit configuration. In a signal generating device of the present invention, a plurality of normal DACs are combined to realize an analog output of a broader bandwidth beyond the output bandwidth of the individual DACs, and the problem of the asymmetricity of the circuit configuration is also resolved. A desired signal is separated into a low-frequency signal and a high-frequency signal in a frequency domain, and a series of operation of constant (r)-folding the amplitude of the high-frequency signal and shifting it on the frequency axis to superimpose it on the low-frequency signal are made in a digital domain. The output of each DAC is switched by an analog multiplexer.

Abstract: A radio base station that communicates with a user terminal, and has a control section that executes control so that signals are time-division-multiplexed over a first radio resource region where symbols are multiplexed at a rate equal to or below a Nyquist rate and a second radio resource region where symbols are multiplexed at a faster rate than the Nyquist rate. The radio base station also includes a transmission section that transmits the signals that are time-division-multiplexed in the first radio resource region and the second radio resource region, to the user terminal to reduce the interference against predetermined signals in a radio communication system in which Faster-Than-Nyquist (FTN) is used.

Abstract: Methods and systems for providing a low-rate data signal. Received input data bits are Manchester modulated onto successive multicarrier symbols in the time domain. Each multicarrier symbol includes orthogonal sub-carrier and a null sub-carrier. A stored waveform can be retrieved to code the sub-carriers. The successive multicarrier symbols are up-converted to a carrier frequency to provide the low-rate data signal, and the low-rate data signal is transmitted.

Abstract: In some embodiments, a network node uses beam frames to broadcast acquisition information on a plurality of beam sets (N). Each beam sets includes a plurality of beams (K). The network node broadcasts the acquisition information one beam set at a time during a corresponding one of a periodic plurality (X) of the beam frames. The periodic plurality (X) of beam frames occur with a first periodicity and are within a periodic plurality (Y) of subframes occurring with a second periodicity.

Abstract: There is provided mechanisms for beamforming using an antenna array. A method is performed by a network node. The method comprises obtaining, from a wireless device, a precoding matrix indicator to be used for transmission to the wireless device. The method comprises selecting a codebook from a set of codebooks according to the received indicator, wherein the selected codebook defines the precoding matrix, and wherein the set of codebooks comprises codebooks defining variable beam widths and having same number of non-zero antenna weights for all beam widths. The method comprises precoding transmission of signals to the wireless device from the antenna array using the selected codebook.

Abstract: A wireless communication terminal apparatus wherein CoMP communication can normally be performed without increasing the overhead of an upstream line control channel. In this apparatus, a spreading unit primarily spreads a response signal by use of a ZAC sequence established by a control unit. A spreading unit secondarily spreads the response signal, to which CP has been added, by use of a block-wise spread code sequence established by the control unit. The control unit controls, in accordance with sequence numbers and a hopping pattern established therein, the circular shift amount of the ZAC sequence to be used for the primary spread in the spreading unit and the block-wise spread code sequence to be used for the secondary spread in the spreading unit. The hopping pattern established in the control unit is a hopping pattern common to a plurality of base stations that CoMP-receive the response signal.

Abstract: An apparatus and a method for determining an antenna characteristic of an antenna under test in free space is disclosed. Measurement results of a transmitted power of a measurement signal transmitted between the reference antenna and an antenna under test are detected, wherein detecting takes place in the frequency domain. The detected measurement results are transformed into the time domain and a time-domain filter is applied to the measurement results converted into the time domain. A filter width of the time-domain filter is determined in dependence on a spatial distance between the reference antenna and the antenna under test. Measurement result portions that result due to a multipath propagation of the measurement signal between the reference antenna and the antenna under test are reduced or removed.

Abstract: A reference signal sequence configuration method includes: selecting, by a network device and from candidate IDs, an ID used for generating a reference signal initialization sequence for a terminal, where the candidate IDs include at least two IDs, and the selected ID does not include a scrambling ID; and generating a reference signal initialization sequence for the terminal according to the selected ID. An implementation manner of the present invention further provides a network device. In the reference signal sequence configuration method and the network device, a reference signal initialization sequence is generated according to the selected ID, thereby providing a manner of generating a reference signal initialization sequence different from the manner in the prior art.

Abstract: Provided are a preamble symbol generation method and receiving method, and a relevant frequency-domain symbol generation method and a relevant device, characterized in that the method comprises: generating a cyclic prefix according to a partial time-domain main body signal truncated from a time-domain main body signal; generating a modulation signal based on a portion or the entirety of the partial time-domain main body signal; and generating time-domain symbols based on at least one of the cyclic prefix, the time-domain main body signal and the modulation signal, wherein the preamble symbol contains at least one of the time-domain symbols.

Abstract: A method and apparatus for transmitting and receiving narrowband (NB) synchronization signals. A base station transmits an NB secondary synchronization signal (SSS) indicating N NB cell identities assigned for NB Internet of Things (IoT) operation, a specific sequence generated by multiplying a base sequence with a cover sequence in element units is used for the NB SSS, wherein the base sequence is generated through a second Zadoff-Chu sequence having a length corresponding to a largest prime number less than a length L in a frequency domain, and the specific sequence is divisionally mapped to and transmitted in a plurality of orthogonal frequency division multiplexing (OFDM) symbols in elements each having a length M.

Abstract: Embodiments of the present disclosure provide a method for signal compensation, including: receiving, by a receiver via N receiving antennas, a plurality of channel estimation preamble signals sent by M transmitting antennas of a remote transmitter; determining, by the receiver, channel estimation parameters according to the first pilot signals of the M transmitting antennas contained in the plurality of channel estimation preamble signals; receiving, by the receiver, data signals and second pilot signals sent on a first data symbol by the M transmitting antennas; determining, by the receiver, channel phase shift parameters according to signals arrived at the N receiving antennas which come from the second pilot signals; and determining, by the receiver according to the channel estimation parameters and the channel phase shift parameters, signal compensation for the data signals arrived at the N receiving antennas. Accuracy of demodulation for transmitted data to a certain extent is improved.

Abstract: A method for performing, by a UE, precoding using a codebook in a wireless communication system includes: receiving a reference signal for channel estimation from an eNB; estimating a channel through the received reference signal; determining a precoding matrix related to the estimated channel in a codebook; and feeding back, to the eNB, a precoding matrix index (PMI) corresponding to the determined precoding matrix, wherein the codebook is generated in consideration of at least one of a region to which the UE belongs and the position of the UE.

Abstract: Disclosed is a downlink signal configuring method and device, and synchronization and cell search method and device using the same in a mobile communication system. A downlink frame has plural symbols into which pilot subcarriers are distributively arranged with respect to time and frequency axes. Initial symbol synchronization and initial frequency synchronization are estimated by using a position at which autocorrelation of a cyclic prefix of a downlink signal and a valid symbol of the downlink is maximized, and cell search and integer-times frequency synchronization are estimated by using pilot subcarriers included in the estimated symbol. Fine symbol synchronization, fine frequency synchronization, and downlink frame synchronization is estimated by using an estimated cell search result.