Abstract: A method for reducing inter-cell interference and a method for transmitting a signal by a collaborative MIMO scheme, in a communication system having a multi-cell environment are disclosed. An example of a method for transmitting, by a mobile station, precoding information in a collaborative MIMO communication system includes determining a precoding matrix set including precoding matrices of one more base stations including a serving base station, based on signal strength of the serving base station, and transmitting information about the precoding matrix set to the serving base station. A mobile station in an edge of a cell performs a collaborative MIMO mode or inter-cell interference mitigation mode using the information about the precoding matrix set collaboratively with neighboring base stations.

Abstract: According to one embodiment, a method for transmitting signals to a receiver, performed by a transmitter including a plurality of antennas, includes: selecting a precoding matrix based on a multiplexing rate (R) by selecting R column vectors from a single matrix corresponding to a maximum multiplexing rate, wherein each column vector of a first precoding matrix corresponding to a first multiplexing rate is included as a part of column vectors of a second precoding matrix corresponding to a second multiplexing rate when the second multiplexing rate is greater than the first multiplexing rate; precoding the signals using the selected precoding matrix; and transmitting the precoded signals to the receiver.

Abstract: A method for reducing inter-cell interference and a method for transmitting a signal by a collaborative MIMO scheme, in a communication system having a multi-cell environment are disclosed. An example of a method for transmitting, by a mobile station, precoding information in a collaborative MIMO communication system includes determining a precoding matrix set including precoding matrices of one more base stations including a serving base station, based on signal strength of the serving base station, and transmitting information about the precoding matrix set to the serving base station. A mobile station in an edge of a cell performs a collaborative MIMO mode or inter-cell interference mitigation mode using the information about the precoding matrix set collaboratively with neighboring base stations.

Abstract: A method of transmitting a channel quality indicator (CQI) includes obtaining CQIs for each of a plurality of sub-bands, a sub-band comprising a plurality of sub-carriers, dividing the plurality of sub-bands into a plurality of layers according to a CQI of a sub-band, a layer comprising at least one sub-band, obtaining a representative value of a representative layer, the representative layer including a sub-band having maximum CQI and transmitting the representative value of the representative layer. Signaling overhead due to CQI feedback can be reduced.

Abstract: A Universal Serial Bus (USB) connector with a connector housing is provided with at least one soldering part and at least one reinforcement part around its circumference. The USB connector includes: a connector housing; one or more soldering parts formed by cutting and unfolding predetermined areas around the circumference of the connector housing; and one or more reinforcement parts, each of which is formed by bending an end of the connector housing. The reinforcement parts being engaged with the soldering parts to support and reinforce the soldering parts, respectively.

Abstract: The present invention relates a method for transmitting and receiving data in a mobile communication system. More specifically, the invention relates to a method through which a terminal in a cell boundary receives data in a mobile communication system that supports MIMO (Multi Input Multi Output). The method comprises: a step for receiving a first data stream transmitted through multiple transmission antennas from a serving base station, a step for pre-coding a second data stream to make the time delay of the second data stream be different from that of the first data stream and receiving the second data stream from a collaborating base station, and a step for restoring the data based on the first and second data streams.

Abstract: The present invention relates to a method for providing control information in a mobile communication system. More specifically, the invention relates to a method for providing control information through a network in mobile communication. The method comprises: a step for configuring the information associated with plural frequency resource groups and the power levels thereof in the control information of preset data format, wherein the plural frequency resource groups are for application of FFR (Fractional Frequency Reuse), and a step for transmitting the control information to at least one terminal.

Abstract: A method of transmitting data using a plurality of subcarriers in a multi-antenna wireless communication system is disclosed. More specifically, the method includes receiving feedback information from a mobile station (MS), performing channel encoding and modulation independently on user data to be transmitted by each antenna using the received feedback information, determining a phase shift-based precoding matrix for increasing a phase angle of the user data by a fixed amount, and performing precoding using the determined phase shift-based precoding matrix on the user data.

Abstract: A method of transmitting pilot symbols is disclosed. In a communication system performing communications using a plurality of antennas and multiple carriers, the present invention includes the steps of generating a plurality of pilot symbol sequences based on a basic code sequence, data-processing a plurality of the pilot symbol sequences by allocating each of a plurality of the pilot symbol sequences to the multiple carriers, and transmitting each of a plurality of the data-processed pilot symbol sequences via a corresponding one of a plurality of the antennas.

Abstract: A method of transmitting data using a plurality of subcarriers in a multi-antenna wireless communication system is disclosed. More specifically, the method includes receiving feedback information from a mobile station (MS), performing channel encoding and modulation independently on user data to be transmitted by each antenna using the received feedback information, determining a phase shift-based precoding matrix for increasing a phase angle of the user data by a fixed amount, and performing precoding using the determined phase shift-based precoding matrix on the user data.

Abstract: A method of data transmission in a wireless communication system having multiple antennas is disclosed. A method of data transmission from a transmitter of a wireless communication system which uses multiple antennas comprises receiving identification information of a precoding matrix from a receiver, the precoding matrix being selected from a codebook generated using a plurality of first matrixes generated by multiplying a discrete fourier transform (DFT) matrix by each of a plurality of phase shift matrixes; precoding data to be transmitted, by using a precoding matrix indicated by the identification information; and transmitting the precoded data to the receiver by using the multiple antennas.

Abstract: A method for allocating fractional frequency reuse (FER) resources to perform cooperative MIMO in a multi-cell environment is disclosed. A cell which requests FER resources decides a band for cooperative MIMO with its neighboring cell, and requests the neighboring cell to allocate the decided band for cooperative MIMO. A cell which receives FER resource request receives a request from a neighboring cell to allocate some or all of FER bands allocated to the neighboring cell as a band for cooperative MIMO, decides whether to grant the request, and allocates some or all of the requested FER bands as the band for cooperative MIMO with the neighboring cell if the request is granted.

Abstract: A method is disclosed for avoiding inter-cell interference in a closed-loop multiple-input multiple-output (MIMO) system using a plurality of codebooks. A base station of a serving cell transmits information about codebooks used in an interfering cell among the plurality of codebooks to a mobile station. The transmission of the information may be made at the request of the mobile station. Alternatively, the mobile station may directly measure information about codebooks used in the interfering cell among the plurality of codebooks. The mobile station measures restricted precoding matrix indexes (PMIs) or requested PMIs based on the codebook information. The measured PMIs are transmitted to the interfering cell and are used to restrict the use of a PMI in the interfering cell.

Abstract: A feedback method for a multi-antenna system is disclosed. The feedback method for use in the multi-antenna system can reduce an amount of transmission (Tx) feedback information associated with a precoding matrix (i.e., a codebook). For example, a single codebook may include precoding matrixes associated with several ranks. A basic matrix constructing the precoding matrix is extended to a frequency axis, such that it can be used as a Cyclic Delay Diversity (CDD) structure.

Abstract: A method for transmitting feedback information in a codebook-based multiple-input multiple-output (MIMO) system is disclosed. For example, a method for transmitting beamforming information in a MIMO system using a codebook-based beamforming scheme includes receiving a signal and estimating a reception channel, and transmitting beamforming information selected through the estimated channel information from a codebook which is updated using phase shift matrices having a phase value as a parameter and using previous beamforming information.

Abstract: There is provided a method of allocating reference signals in a multiple-input multiple-output (MIMO) system. The method includes allocating a first reference signal, a second reference signal and a third reference signal in a first OFDM symbol so that the first reference signal, the second reference signal and the third reference signal do not overlap with each other and allocating the first reference signal, the second reference signal and a fourth reference signal in a second OFDM symbol so that the first reference signal, the second reference signal and the fourth reference signal do not overlap with each other. The first reference signal and the second signal are allocated in a regular interval in a single OFDM symbol.

Abstract: Precoding methods and method for performing precoding and methods of transmitting feedback information for precoding or transmitting a signal using a multi-codebook and method of transceiving precoding information in a multi-antenna system, where a signal transmitting method in a multi-antenna system, and more particularly, a method of transceiving precoding matrix information for a multi-input multi-output (MIMO) system is disclosed. The present invention proposes a method of performing communications using an expanded unitary matrix generated from shifting a phase of a base unitary matrix. The present invention is applicable to single user MIMO, multi-user MIMO, beam forming, etc.

Abstract: Methods of controlling a transmission power and configuring a codebook in a multi-antenna system to solve a transmission power unbalance between antennas are disclosed. The method of transmitting data in a multi-antenna system includes (A) transmitting one or more pilot signals within a first symbol region through a first antenna unit, and (B) transmitting one or more pilot signals within a second symbol region through a second antenna unit, wherein data within the first symbol region is transmitted through the second antenna unit, and data within the second symbol region is transmitted through the first antenna unit. According to the present invention, since a transmission power unbalance between antennas is solved, a transmission power can be uniformly assigned to each antenna and channel estimation can be easily performed. Moreover, a power amplifier having a uniform amplification range can be used and designed.

Abstract: A method for transmitting and receiving data in a cooperative Multiple-Input Multiple-Output (MIMO) mobile communication system is disclosed. The method includes selecting a transmission path for transmitting precoding-related feedback control information to one or more cooperative base stations operating in the cooperative MIMO mode, and transmitting the precoding-related feedback control information to the one or more cooperative base stations through the selected transmission path.

Abstract: A method for avoiding an inter-cell interference (ICI) in a multi-cell environment is disclosed. The method includes restricting the use of a PMI in an interfering cell so as to improve a reception performance of a mobile station located at an interfered cell edge. The mobile station measures a restricted-PMI of the interfering cell, which is prohibited from use in the interfering cell, and transmits the measured restricted PMI to the interfering cell. The use of the restricted PMI is prohibited from use in a mobile station in the interfering cell.