Abstract: Provided is a method and a device for generating a precoding matrix in a wireless communication system. The method for generating the precoding matrix comprises a step of receiving from a terminal feedback including information on the error angle ? of channel direction information (CDI), which indicates the direction of a channel direction vector, and a step of generating the precoding matrix based on the information on the error angle ? of the CDI, wherein the error angle ? of the CDI indicates the angle between the channel direction vector and a quantized channel direction vector, and includes at least one of a channel quantization error component, a channel feedback delay error component, and a channel estimation error component.

Abstract: The present invention relates to a method and apparatus for receiving a white space map in a wireless LAN system. According to one aspect of the present invention, in a method in which a first station (STA) receives a white space map in a wireless LAN system, wherein the first station operates as an unlicensed device that is allowed to operate in an available channel not used by a licensed device in a white space band, the first station receives, from a second station, a frame including the white space map which includes a black list and a first field for indicating that the white space map contains the black list, and operates in at least one channel from the rest of the channels in TVWS, excluding the channel contained in the black list, wherein the black list is a list of channels which cannot be used by the unlicensed device.

Abstract: Provided is a method for transmitting a sounding reference signal (SRS) of a relay station. The method includes: receiving SRS parameters; allocating a radio resource by using the SRS parameters; and transmitting the SRS to a base station by using the radio resource, wherein the radio resource indicated by the SRS parameters includes a symbol in which a guard time for switching signal transmission and reception is located in a time domain.

Abstract: Techniques for efficiently sending channel state information using differential encoding are described. Differential encoding may be performed across space, across frequency, across space and frequency, across space, frequency and time, or across some other combination of dimensions. In one design, spatial state information may be determined for multiple spatial channels on multiple subbands. The spatial channels may correspond to different antennas, different precoding vectors, etc. Channel quality indicator (CQI) values may be obtained for the multiple spatial channels on the multiple subbands. The CQI values may be differentially encoded across the multiple spatial channels and the multiple subbands to obtain differential CQI information. In another design, CQI values may be obtained for multiple spatial channels on the multiple subbands in multiple time intervals and may be differentially encoded across space, frequency and time.

Abstract: Techniques for sending control information in a wireless communication system are described. In an aspect, a UE spreads control information across frequency with a DFT and across time with an orthogonal sequence to obtain output data for the control information. In one design, the UE receives codewords for N HARQ processes in N downlink subframes, determines an ACK value for each HARQ process, codes N ACK values for the N HARQ processes to obtain ACK information, generates output data for the ACK information, and sends the output data in one of M uplink subframes. In another aspect, first control information is processed based on a first coding and multiplexing scheme utilizing code division multiplexing in time and frequency domains. Second control information is processed based on a second coding and multiplexing scheme utilizing code division multiplexing in time domain and spreading in frequency domain.

Abstract: Techniques for performing rank-dependent precoding for a Mulitple-Input Multiple-Output (MIMO) transmission are described. Each rank may be associated with a set of at least one precoding vector or matrix that can provide good performance for that rank. A transmitter may obtain a precoding vector for a rank-1 transmission from a first set containing at least one column vector of a unitary matrix, e.g., a Fourier matrix. The transmitter may perform precoding for the rank-1 transmission based on the precoding vector. The transmitter may obtain a precoding matrix for a rank-2 transmission from a second set containing an identity matrix. The transmitter may perform precoding for the rank-2 transmission based on the precoding matrix. For the rank-2 transmission, the transmitter may select the identity matrix as the precoding matrix if a MIMO channel resembles a diagonal channel (which may be determined based on antenna configurations) and may select the unitary matrix otherwise.

Abstract: Techniques for facilitating cell search by user equipments (UEs) in a wireless communication system are described. In an aspect, a primary synchronization code (PSC) sequence may be generated based on a Frank sequence and a constant amplitude sequence that is repeated multiple times. In another aspect, a set of PSC sequences may be generated based on complementary sequences having good aperiodic correlation properties and efficient implementations. In one design, PSC sequences A+B and B+A may be formed based on Golay complementary sequences A and B, there “+” denotes concatenation. In yet another aspect, a set of secondary synchronization code (SSC) sequences may be generated based on a set of base sequences and different modulation symbols of a modulation scheme. Each base sequence may be modulated by each of M possible modulation symbols for the modulation scheme to obtain M different SSC sequences.

Abstract: A method and apparatus of transmitting a reference signal in a wireless communication system is provided. The method includes generating a precoded reference signal or a non-precoded reference signal in accordance with a rank, and transmitting the generated reference signal. Uplink transmission using multiple transmit antennas is supported through reference signal design and related control signaling.

Abstract: A method and apparatus for transmitting a downlink reference signal in a wireless communication system supporting multiple antennas is disclosed. A method for transmitting Channel State Information-Reference Signals (CSI-RSs) for eight or less antenna ports includes selecting one of a plurality of CSI-RS Resource Element (RE) groups defined on a data region of a downlink subframe and mapping CSI-RSs for the eight or less antenna ports to the selected CSI-RS RE group, and transmitting the downlink subframe in which the CSI-RSs for the eight or less antenna ports are mapped. The plurality of CSI-RS RE groups is defined such that a transmission diversity RE pair for data transmitted on the downlink subframe is not broken.

Abstract: Methods and systems are disclosed for channel estimation and frequency tracking in mobile communication systems. Particularly, various ways of using the time domain impulse channel response based on the staggered frequency domain pilot tones are presented that enable rapid frequency error estimation and frequency tracking control. A mathematical model is developed that provides a convenient metric for evaluating tolerable frequency error, as well as modes for switching between channel impulse response (CIR)-based and secondary synchronization channel (SSC)-based frequency tracking.

Abstract: Aspects relate to a flexible interleaving scheme that provides frequency diversity to randomizes interference Frequency diversity groups can be utilized, wherein control channel elements (CCEs) gain greater frequency diversity for a given number of mini-CCEs (e.g., subset of CCEs). A frequency diversity group index is permuted according to a bit reversed scheme to facilitate control channel elements with a small number of mini-CCEs to also gain sufficient frequency diversity.

Abstract: Specifically, according to one embodiment of the present invention, a method for searching for an access point is provided. The method for searching may comprises the steps of: a terminal measuring the position thereof; checking an access point located near the measured position of the terminal; determining whether or not the distance between the terminal and the access point is greater than the radius range searchable by the terminal; and searching for the access point when the distance between the terminal and the access point is less than the radius range.

Abstract: A station forms a connection with a first access point (AP): a particular station for storing first active station identification information of an active station that manages the activation of the station serviced by said first AP accesses a region serviced by a second AP, and receives from said second AP a message for containing second active station identification information of the active station that manages the activation of the station serviced by said second AP; said first active station identification information is compared with said second active station identification information; and if said first active station identification information is different from said second active station identification information, a procedure for changing the active station and a handover to said second AP are performed to a second active STA corresponding to said second active station identification information.

Abstract: The present invention relates to a method and apparatus for receiving available channel information in a wireless LAN system. According to one aspect of the present invention, in a method in which a first station (STA) receives available channel information in a wireless LAN system, wherein the first station operates as an unlicensed device that is allowed to operate in an available channel not used by a licensed device in a white space band, the first station receives, from a second station, a frame including an operating class field, a channel number field and a maximum transmission power field, and operates in the channel indicated by the operating class field and the channel number field, wherein said operating class field and said channel number field indicate the available channel which can be used by the unlicensed device, and said maximum transmission power field indicates the maximum transmission power permitted in the available channel.

Abstract: Provided is a method of transmitting a signal related to a change in a transmission format. In a wireless communication system which uses an orthogonal frequency division multiplexing (OFDM) symbol or a single carrier-frequency division multiple access (SC-FDMA) symbol, the method includes: transmitting, from a base station to a receiver, a radio resource control (RRC) message indicating that a first transmission format is changed to a second transmission format; and if an acknowledgement (ACK) message for the RRC message is not received, repetitively transmitting the RRC message, from the base station to the receiver, together with data based on the first transmission format or data based on the second transmission format, wherein the data based on the first transmission format and the data based on the second transmission format transmitted together with the RRC message are alternately selected.

Abstract: Various methods and systems for determining reverse-link data rates in a multi-user communication system are disclosed. For example, an apparatus for controlling a data rate of at least a first UE in a multi-user communication system is disclosed. The apparatus may include a channel estimation device configured to determine channel estimates for a plurality of different reverse-link signals to produce a plurality of channel estimates, a demodulation device configured to determine a first signal-to-noise (SNR) ratio for the first UE using the plurality of different channels estimates, and a data rate determining device configured to determine a first reverse-link data rate for the first UE using the first SNR.

Abstract: Techniques for selecting transmit formats in a manner to account for the degrees of resource reuse for multiple data streams sent simultaneously from multiple antennas are described. The degree of resource reuse for each data stream indicates the amount of reuse of resources (e.g., orthogonal codes or subcarriers) observed by that stream. Interference estimates for the multiple data streams are derived based on an initial resource assignment. The degrees of resource reuse are determined based on the interference estimates and are used to derive at least one correction factor. At least one transmit format is then selected for the data streams using the at least one correction factor. Each data stream is associated with a transmit format that indicates the amount of resources to use for the data stream and other parameters. Resources are assigned to each data stream in accordance with its transmit format.

Abstract: The present invention relates to a method in which a base station transmits signals to a relay node in a multiuser multi-antenna (MIMO) wireless communication system. More particularly, the method comprises the following steps: allocating one or more antenna ports to one or more relay nodes, respectively; mapping each of a plurality of downlink grant signals for said one or more relay nodes to a preset resource domain from among resource domains corresponding to one of the allocated antenna ports; mapping uplink grant signals or data signals for said one or more relay nodes to the resource domains corresponding to the allocated antenna ports; and transmitting the mapped signals to said one or more relay nodes.

Abstract: Systems and methodologies are described that facilitate computing discriminator signals for frequency tracking in wireless communications. The discriminator signal can be computed based at least in part on representations of a received signal shifted upward by a portion of a frequency tone and downward by the portion of the frequency tone. The shifted signals can be summed, and a dot product of the summed signals and a channel estimation of the original signal can be computed to remove uncertain frequency response due to fading. The discriminator signal can be computed as the imaginary portion of the dot product. A frequency error offset can be determined from the discriminator signal and applied to a receiver to tune alignment of the receiver with frequencies of received signals.

Abstract: The present invention relates to a method for transmitting signals by a base station in a wireless communication system, the method comprising: resetting a start symbol index for a relay node dedicated downlink physical control channel and a relay node dedicated downlink physical common channel, respectively; transmitting a message including a parameter required for resetting the start symbol index to the relay node; setting the start symbol index to a preset value or a value that has been given prior to receiving the reestablishment message, in the case where the relay node has sent a specific number of NACKs for the relay node dedicated downlink physical control channel or the relay node dedicated downlink physical common channel; and transmitting the relay node dedicated downlink physical control channel and the relay node dedicated downlink physical common channel to the relay node, based on the start symbol index having been set.