Abstract: In performing SVD-MIMO transmission, a set-up procedure is simplified while assuring a satisfactory decoding capability with a reduced number of antennas. A transmitter estimates channel information based on reference signals sent from a receiver, determines a transmit antenna weighting coefficient matrix based on the channel information, calculates a weight to be assigned to each of components of a multiplexed signal, and sends, to the receiver, training signals for respective signal components, the training signals being weighted by the calculated weights. On the other hand, the receiver determines a receive antenna weighting coefficient matrix based on the received training signals.

Abstract: A system that incorporates the subject disclosure may include, for example, a circuit for initiating a first multiple-input and multiple-output (MIMO) communication session with a primary base station, and initiating a second MIMO communication session with a first secondary base station of a plurality of secondary base stations without terminating the first MIMO communication session with the primary base station. The primary base station can include a primary antenna system having a first communication range, while each of the plurality of secondary base stations can include a secondary antenna system having a second communication range that is a subset of the first communication range of the primary antenna system. The plurality of secondary base stations can correspond to a plurality of small cell sites distributed within the first communication range of the primary base station. Other embodiments are disclosed.

Abstract: A method for transmitting a data packet includes prepending to the digital contents of the data packet a preamble including a first preamble field having a plurality of repetitions of a sequence. The method also includes determining according to a specified communication protocol a first transmission power level for the data packet and determining according to the specified communication protocol and the first preamble field an unadjusted transmission power level for the first preamble field. The method further includes determining the presence of one or more power-boost characteristics of the data packet or of an intended receiving client, transmitting the first preamble field at a first adjusted transmission power level if one or more power-boost characteristics are determined to be present, and transmitting a remainder of the data packet at the first transmission power level for the data packet.

Abstract: The invention is directed to a method and system for supporting MIMO technologies which can require the transport of multiple spatial streams on a traditional Distributed Antenna System (DAS). According to the invention, at one end of the DAS, each spatial stream is shifted in frequency to a pre-assigned band (such as a band at a frequency lower than the native frequency) that does not overlap the band assigned to other spatial streams (or the band of any other services being carried by the DAS). Each of the spatial streams can be combined and transmitted as a combined signal over a common coaxial cable. At the other “end” of the DAS, the different streams are shifted back to their original (overlapping) frequencies but retain their individual “identities” by being radiated through physically separate antenna elements.

Abstract: Systems and methods are provided for decoding signal vectors in multiple-input multiple-output (MIMO) systems, where the receiver has received one or more signal vectors based on the same transmitted vector. The receiver linearizes each received signal vector using one or more zero-forcing, MMSE, or other suitable linear equalizers. The components of the equalized signal vectors may be combined using maximum-ratio combining to form the components of a combined equalized signal vector. The components of the combined equalized signal vector may then be decoded individually using a linear decoder.

Abstract: There is provided a communication apparatus capable of effectively removing interference waves from a received signal while reducing the computation load. The communication apparatus includes a weight calculating unit. The weight calculating unit includes a calculating unit and a selecting unit. The calculating unit calculates a first weight and a second weight. The first weight is obtained, for a target known signal being an update target, by updating, using the target known signal, a weight of a first another known signal updated immediately before performing an update using the target known signal. The second weight is obtained, for a target known signal being an update target, by updating, using the target known signal, a weight of a second another known signal. The selecting unit selects one of the first weight and the second weight that has a lower estimation error.

Abstract: A method for transmitting uplink control information and a corresponding device, where the method which include receiving at least one of one or more PDCCH signals and one or more PDSCH signals and generating entire received response information with respect to one or more PDCCH signals and one or more PDSCH signals. Multiple received response information are contained in entire received response information and generated per cell and per subframe. If being a subframe in which a plurality of transport blocks (TBs) are received in a cell, DTX (discontinuous transmission) state and all negative acknowledgement (NACK) state are mapped to same bit values for the cell and the subframe. If being a subframe in which only one TB is received in a cell, DTX state and all NACK state are mapped to different bit values for the cell and the subframe.

Abstract: A method of enhancing performance of downlink multi-user multiple-input-multiple-output transmissions in a wireless communication system comprising a communication device and a network is disclosed. The method comprises generating a feedback report comprising a correlation-based validity threshold (CVT); and transmitting the feedback report from the communication device to the network.

Abstract: Methods and apparatus for enhancing a search performance for timing includes a mobile station that detects a plurality of signals, each from one of a plurality of cells, wherein one of the plurality of cells is identified by the mobile station as a strong cell and the remaining cells are identified by the mobile station as weak cells. A first matched filter is applied to a signal from the strong cell to detect first parameters associated with the strong cell. A second matched filter is applied to at least one signal from one or more of the weak cells resulting in at least one second matched filter output. Interference is removed from the at least one second matched filter output to detect one or more second parameters associated with one of the weak cells and to establish a timing of one of the weak cells.

Abstract: Data streams stored in buffers are modulated by modulation sections. Multipliers multiply the signals output from the modulation sections by weights output from a weight control section. The signals output from the multipliers are added up by addition sections, subjected to radio transmission processing by transmission radio sections and sent through antennas. A buffer control section controls the buffers based on a retransmission count output from a retransmission count detection section. The weight control section outputs weights different from weights at the time of previous transmission to the multipliers every time data is retransmitted. This allows a diversity gain at the time of data retransmission to be increased even if a time variation of the propagation path environment for radio signals is slow.

Abstract: Channel characterization and training within multiple user, multiple access, and/or MIMO wireless communications. Within such communication systems, there can be a number of devices (e.g., STAs) that communicate with a single device (e.g., AP). A multi-cast sounding frame may be transmitted from a transmitting device to a number of receiving devices. Appropriate scheduling or ordering of feedback signals from some or all of the receiving devices may be performed explicitly (e.g., sounding frame sent from the transmitting device to a receiving device) or implicitly (e.g., control information sent from the transmitting device to the receiving device, sounding frame sent to the transmitting device from the receiving device). Such characterization and training is with respect to a channel or path in which data will subsequently follow. Such characterization and training can be performed in accordance with group membership (e.g., with respect to only some of the receiving devices).

Abstract: A system and method for wireless communication over multi-rate channels are disclosed. One embodiment of the system includes a first multi-band wireless station that is capable of using a first frequency band and a second frequency band for wireless communication; and a second multi-band wireless station that is capable of using the first frequency band and the second frequency band for wireless communication. One or more of the first and second stations is configured to monitor a status of the second frequency band. The status includes the availability of the second frequency band for communication between the first and second stations. The first and second stations can share the monitored status with each other via the first frequency band.

Abstract: A method and an apparatus in a first wireless station of a network transmitting to a second wireless station. The network uses multi-tone OFDM signals. The first station includes multiple antennas and a receive and a transmit signal path per antenna. Each receive signal path includes a discrete Fourier transformer determining the tones in a received signal, and each transmit signal path includes an inverse discrete Fourier transformer converting tones to a signal. The method includes determining channel estimates for each tone and each receive path while receiving from the second station, determining transmit weights to transmit to the second station, tone-by-tone weighting a signal for transmission to the second station to produce weighted tone sets for each transmit signal path, and transmitting the weighted tone sets. The first station is configured so that the weighting produces additive beamforming without the second station needing multiple antennas.

Abstract: A user equipment (UE) monitors coexistence issues of one or more associated communication resources. The UE initiates link recovery procedures (e.g., declaring a Radio Link Failure (RLF)) in response to the monitoring when a coexistence issue is detected. The UE can also access a new channel or a new Radio Access Technology (RAT) in response to initiating the link recovery. The network may have the ability to control whether the UE can initiate the link recovery.

Abstract: For downlink communication with a communication terminal using a downlink radio resource allocated to this communication terminal by a radio resource allocating unit, if this communication terminal does not transmit a first known signal using an associated uplink radio resource associated with this downlink radio resource but it transmits the first known signal using a nonassociated uplink radio resource which is not associated with this downlink radio resource and which includes the frequency band of this downlink radio resource in a frequency direction, a communication unit controls the transmission directivity of a plurality of antennas based on a second known signal if the aforementioned communication terminal transmits the second known signal in the frequency band of the aforementioned downlink radio resource in an interval between a time period of this downlink radio resource and a time period of the aforementioned nonassociated uplink radio resource.

Abstract: A method for configuring gain factors in a WCDMA telecommunication system is provided in which the gain factor for defining power required for normal reception of uplink data in an environment supporting an uplink service over an E-DCH can be configured using minimal signaling information. First gain factors for first TFs corresponding to a part of a TF set including a plurality of TFs available for an uplink service are received. One of the first TFs is determined as a reference TF for a second TF other than the first TFs in the TF set. Then, a second gain factor for the second TF is calculated using the first gain factor for the determined reference TF. The second gain factor is used for transmitting or receiving uplink data.

Abstract: A method is provided to reduce inter-cell interference in mobile wireless systems, and particularly in TDD wireless systems. In an embodiment, a base station receives a pilot signal from at least one of the mobile terminals that it serves at a plurality of base station antennas, which include both main antennas and auxiliary antennas. In response, each of the base station antennas provides an output that is processed to obtain a set of precoding weights for a transmission from the main antennas. The processing includes nulling at least one interfering signal using the outputs from at least the auxiliary antennas.

Abstract: Methods and apparatus are provided for directing a beam towards a receiving device in the presence of interference. A beam transmitted by a transmission source is received by a received device. The beam shape is affected by signals transmitted by interfering sources. The receiving device computes channel estimates associated with the transmission source and the interfering sources. A feedback signal that represents the channel estimates associated with the transmission and interfering sources is transmitted to the transmission source. The transmission source changes characteristics of the beam to compensate for the interference caused by the interfering sources. The transmission source may change the characteristics of the beam by performing precoding algorithms.

Abstract: In one embodiment, a method of transmitting system information on a down link shared channel structured as successive subframes includes transmitting (400-416) system information in regularly occurring time windows, each time window spanning some number of successive subframes. The method further includes indicating (406/408) to receiving user equipment (120) which subframes within a given time window carry system information. The method and variations of it are applied, for example, to the transmission of dynamic system information on the down link shared channel or other down link channel in a 3GPP E-UTRA wireless communication network (100).

Abstract: An apparatus and method for generating a codebook in a wireless communication system are disclosed. The codebook generation apparatus includes a processor for generating a covariance matrix of a channel between the transmitting end and a receiving end, using a unitary matrix including a first vector corresponding to at least one quantized dominant singular singular vector of the channel and a second vector corresponding to at least one basis vector of a null space of the first vector, and transforming a predefined first codebook by applying the covariance matrix of the channel to the first codebook.

Abstract: Pilot, preamble and midamble patterns are provided that are particularly suited for four transmit antenna OFDM systems. Pilots are inserted in a scattered manner for each of the four antennas, either uncoded, space-time coded in pairs, space-time frequency coded in pairs, or space-time-frequency coded.

Abstract: A method for processing a preamble of a data unit transmitted via a communication channel includes receiving a signal via a plurality of antennas, applying a plurality of distinct steering vectors to the received signal to generate a plurality of respective outputs, and using the plurality of outputs to perform at least one of carrier sensing and symbol timing synchronization associated with the preamble.

Abstract: A system and method for overriding Carrier-Sense-Multiple-Access/Collision-Avoidance (CSMA/CA) and virtual carrier sense, without harming the traffic that occupies the channel is described herein. Further provided herein are measurements and qualifying criteria for performing the aforementioned channel sharing. The system and method may be based, for example, on opportunistic spatial isolation of nodes from each other and selectively implementing ultra-fast link adaptation.

Abstract: The present invention relates to the field of telecommunications, and discloses a method for indicating an MU-MIMO mode. In this method, first part information and second part information are constructed and sent, where formats of the first part information and the second part information indicate an MU-MIMO mode. The present invention further discloses an apparatus for indicating an MU-MIMO mode. With the method and apparatus for indicating an MU-MIMO mode, where the method and apparatus for indicating an MU-MIMO mode are disclosed in the present invention, a UE may be notified of being configured with an MU-MIMO mode when MU-MIMO is applied in a UMTS system.

Abstract: Systems and methods are described for wireless backhaul in a multiple antenna system (MAS) with multi-user (MU) transmissions (“MU-MAS”). For example, a multiuser (MU) multiple antenna system (MAS) of one embodiment comprises: one or more centralized units communicatively coupled to multiple distributed transceiver stations via a network; the network consisting of wireline or wireless links or a combination of both, employed as a backhaul communication channel; the centralized unit transforming the N streams of information into M streams of bits, each stream of bits being a combination of some or all N streams of information; the M streams of bits being sent over the network to the distributed transceiver stations; the distributed transceiver stations simultaneously sending the streams of bits over wireless links to at least one client device such that at least one client device receives at least one of the original N streams of information.

Abstract: A method for transmitting a sounding reference signal from a user equipment in a MIMO antenna wireless communication system. The method includes receiving sounding reference signal setup information from a base station, the sounding reference signal setup information including an initial cyclic shift value nSRScs and an initial transmissionComb parameter value kTC; setting an interval between cyclic shift values corresponding to each antenna port based on the initial cyclic shift value, to reach a maximum interval; setting a transmissionComb parameter value corresponding to a specific one of the antenna ports to a value different from the initial transmissionComb parameter value if the initial cyclic shift value is a previously set value and the number of antenna ports is 4; and transmitting the sounding reference signal to the base station through each antenna port by using the set cyclic shift value and transmissionComb parameter value.

Abstract: In retransmission processing due to a failure of transmission of data packets, a plurality of data packets are simultaneously transmitted between two STAs by utilizing multiple wireless channels and MIMO, and the number of idle channels and the number of retransmission packets are compared. Then, when both of the numbers are different or only when the number of idle channels is larger than the number of retransmission packets, the retransmission packets are reconstructed according to the number of idle channels, and the reconstructed retransmission packets are simultaneously transmitted by using the idle channels.

Abstract: A radio base station 100 judges a receiving state of a radio signal in conformity with the orthogonal frequency division multiplexing scheme, and changes a symbol string configuration of a symbol string defined by a size in a frequency axis direction and in a time axis direction, on the basis of the judged receiving state.

Abstract: A method and system supporting handoff of a multimedia call session using background network scanning is disclosed. A mobile multimedia handset may engage in the exchange of a multimedia information stream via a first wireless network, and may sniff a portion of radio frequency spectrum for a second wireless network. Information about available services and network quality of service for the second network may be received by querying the second wireless network or from advertising by the second wireless network. Hand-off between the two networks may be based upon the results of the comparison and one or more user-defined criteria, and the handoff may be synchronized according to predefined events in the stream of multimedia information.

Abstract: The present invention relates to transmitting a downlink reference signal in a wireless communication system. A method for a base station to transmit a downlink signal by using two or more layers includes multiplexing and transmitting a reference signal for the two or more layers on the basis of a reference signal pattern on a data region of a downlink subframe and transmitting data for the two or more layers on the data region of the downlink subframe, wherein the reference signal for the two or more layers is a dedicated reference signal that is used to demodulate the data for the two or more layers on a receiving end, and in the multiplexing of the reference signal, the reference signal for the two or more layers is code-division-multiplexed by an orthogonal code having a length of at least 2.

Abstract: A display apparatus and a method of searching for a channel in the display apparatus includes a plurality of tuners and a plurality of antenna ports respectively connected to the plurality of tuners. The method includes receiving a channel search command; if the channel search command is input, searching for one of the plurality of antenna ports that is connected to a satellite antenna to receive a broadcasting signal, if one of the plurality of antenna ports is connected to the satellite antenna to receive the broadcasting signal, setting one of the plurality of tuners connected to the one antenna port, to a main tuner, and performing a channel search through the tuner set to the main tuner. Therefore, although an antenna port connected to one of the plurality of tuners initially set to a sub tuner, the display apparatus performs a channel search through the corresponding tuner.

Abstract: In a wireless communication device, in a correction value calculating mode, a control unit flips switches to the “a” sides, a modulation processing unit generates a CW signal as an I channel signal, a DAC converts the digital CW signal into an analog CW signal, an LPF eliminates the high-frequency component from the CW signal, a mixer functions as an up-converter for up-converting the CW signal, a PA amplifies the RF power of the CW signal, a mixer functions as a down-converter for down-converting the CW signal, an ADC converts the analog CW signal into a digital CW signal, a level detecting unit detects the voltage level of the CW signal, a correction value calculating unit calculates a correction value based on the detected voltage level, and a correction value storing unit stores the calculated correction value.

Abstract: A system including a stream generator module to generate a plurality of streams to be transmitted in a packet. The packet is to be transmitted to a plurality of client stations. First streams are designated for a first client station and include a plurality of training fields. Second streams are designated for a second client station and include the plurality of training fields. A cyclic shift delay module applies a plurality of cyclic shift delay values to the plurality of streams. First values from the plurality of cyclic shift delay values are respectively applied to the first streams. Second values from the plurality of cyclic shift delay values are respectively applied to the second streams. A mapping module spatially maps the plurality of streams subsequent to the cyclic shift delay module applying the cyclic shift delay values to the plurality of streams.

Abstract: A wireless network device comprising a physical layer (PHY) module and a media access control (MAC) module. The PHY module is configured to communicate with an 80 MHz channel. The 80 MHz channel includes a plurality of sub-bands including a first sub-band, a second sub-band, a third sub-band, and a fourth sub-band. One of the plurality of sub-bands corresponds to a primary channel. The PHY module is further configured to determine which of the plurality of sub-bands are receiving a data packet, and generate at least one clear channel assessment signal indicating which of the plurality of sub-bands are receiving the data packet. The MAC module is configured to receive the at least one clear channel assessment signal from the PHY module, and selectively transmit on the primary channel based on the at least one clear channel assessment signal.

Abstract: Method, receiver and computer program product for processing a signal, wherein the signal is received over a wireless network from a transmitter, the signal comprising a plurality of data streams. A selected one of the data streams is preferentially treated by reporting an adjusted value of a characteristic of the selected data stream to the transmitter and the received signal is decoded using a technique of successively decoding data streams in which the selected data stream is the first data stream to be decoded, a signal corresponding to the selected data stream being removed from the received signal prior to decoding at least one of the unselected data streams in the received signal.

Abstract: Radio frequency (RF) architectures for spectrum access networks are provided. Embodiments of the invention generally provide a radio frequency (RF) architecture for customer premise equipment (CPE) for use in, for example, IEEE 802.22 wireless regional area networks (WRANs). In some embodiments, the CPE RF architecture includes two receive chains with a directional antenna and an omni-directional antenna, respectively. The CPE RF architecture facilitates opportunistic out-of-band spectrum sensing and WRAN signal receiving that are performed in parallel with data transmission.

Abstract: A sounding reference signal transmission method which is efficient in an uplink wireless telecommunications system using a multiple antenna technique and sounding reference signal hopping. A terminal using the multiple antenna technique is equipped with a plurality of antennas, and a base station receives the sounding reference signal transmitted from these antennas and estimates the uplink channel state of each antenna. Moreover, the sounding reference signal performs frequency hopping so that the base station determines the channel condition for the entire bandwidth to which data is transmitted in the uplink system. The sounding reference signal is transmitted through an antenna pattern in which the sounding reference signal can be transmitted through the entire data transmission bandwidth of the uplink system for each antenna of the terminal without additional overhead in this environment.

Abstract: The present invention relates to wireless communication, and more specifically, to a method and device whereby a base station allocates nodes to a terminal in a semi-static fashion in a multi-node system. The method, according to one aspect of the present invention, whereby a base station allocates at least a portion of a plurality of nodes to a terminal in a multi-node system comprising the plurality of nodes and the base station for controlling the plurality of nodes, comprises the steps of: receiving, from the terminal, data showing at least one first node that is preferred among the plurality of nodes by the terminal; and transmitting, to the terminal, first data for allocating the first node(s) to the terminal. The first data may comprise pilot data which is required by the terminal in order to transmit, to the base station, feedback data concerning the first node.

Abstract: In a wireless local are network, each of multiple access points, in a high density deployment, are configured to suppress co-channel interference. A first access point having a plurality of antennas beamforms a transmission to a wireless client device within a null-space or with the weakest singular eigenmodes of a wireless channel between the first access point and at least one co-channel second access point. Techniques are presented herein for situations in which any given access point has two or more co-channel access points. In addition, an access point may perform receive side suppression with respect to a transmission (made by a co-channel access point to one of its associated wireless client devices) that is received from that co-channel access point.

Abstract: A transmission method for transmitting a first modulated signal and a second modulated signal in the same frequency at the same time. Each signal has been modulated according to a different modulation scheme. The transmission method applies precoding on both signals using a fixed precoding matrix, applies different power change to each signal, and regularly changes the phase of at least one of the signals, thereby improving received data signal quality for a reception device.

Abstract: A channel sounding method in a wireless local area network (WLAN) system is provided. The method, performed by a transmitter, includes transmitting a null data packet announcement (NDPA) frame to a receiver to initiate a channel sounding procedure; transmitting a null data packet (NDP) to the receiver and receiving a feedback frame. The feedback frame includes a plurality of segment frames and a channel feedback report. The channel feedback report is split into a plurality of feedback segments. Each of the plurality of feedback segments is respectively included in each of the plurality of segment frames. The each of the plurality of segment frames includes a first-segment subfield indicating whether the each of the plurality of feedback segment included is a first segment and a remaining-segment subfield indicating the number of remaining feedback segments.

Abstract: When a mobile terminal transmitting/receiving a packet using a plurality of IP address types performs a handover to an access network (single address type connection network) permitting transmission/reception of a packet using a single IP address only, an IP address not permitted is unfortunately discarded at an access network as a handover destination. Disclosed is a technique configured so that a mobile terminal (UE 1) detecting a handover to the single address type connection network establishes a temporary connection with a mobility management gateway (PGW 5) and thereafter acquires an address of an ePDG 8 located at a core network and informs the ePDG of a communication state before the handover via a PDN using the temporary connection. The ePDG informs the PGW of the communication state of the UE before the handover. Thereby, the communication state of the UE before the handover is achieved with the PGW via the ePDG and the PDN.

Abstract: Uplink transmission from a mobile device having multiple antennas to a base station having multiple antennas includes transmitting in an open-loop single-user MIMO mode when the mobile device is at high speed, transmitting in a closed-loop single-user MIMO mode when the mobile device is at low speed, and, upon request, transmitting in a multi-user collaborative MIMO mode. The method also includes controlling uplink transmissions in a selected one of the open-loop single-user MIMO, the closed-loop single-user MIMO and the multiuser collaborative MIMO modes. Uplink transmissions from the mobile device may be transmitted using multiple antennas of the mobile device. Upon request, the mobile device may switch to transmitting in multi-user collaborative MIMO mode with a subset of the multiple antennas.

Abstract: Systems, methods, and software for operating communication systems and wireless communication devices are provided herein. In one example, a method of operating a wireless communication is provided. In security circuitry of the wireless communication device, the method includes receiving a request from processing circuitry for an application to access a first communication network with a first communication transceiver, and processing the request and a security key to authorize the application to use the first communication transceiver to access the first communication network. In the first communication transceiver, the method includes exchanging communications over the first communication network for the application responsive to the authorization.

Abstract: A receiving apparatus for communication area evaluation includes a receiving unit configured to receive a first signal transmitted from a base station; a delay profile calculation unit configured to calculate a downlink delay profile based on the first signal; and an estimated value calculation unit configured to calculate an estimated cyclic prefix length based on the calculated downlink delay profile.

Abstract: A cradle adapter connection allows I/O contacts between a non-wireless device (NWD) and a wireless cradle adapter or similar wireless enabling attachment. The enabling attachment can make any non-wireless device (NWD) unit wireless enabled while being plugged into the cradle adapter, in a similar manner as shown for a cell telephone/mobile device (CT/MD), to access a number of wired, optical or wireless communication paths through the ports. The cradle adapter itself may have multiple antennas, multiple T/R units and multiple processors built-in to deliver full functionality, and it may also accommodate multiple wired or wireless devices to be plugged in at the same time. The cradle adapter may contain power ports for the individual devices in addition to the I/O ports, and it may be a passive pass through-connection enabling device or may have internal electronics to perform certain server functions to control data traffic.

Abstract: There are provided measures for a pathloss-based access node wake-up control, more specifically a pathloss-based access node wake-up control in a heterogeneous network environment. Such measures exemplarily include a retrieval of an average handover pathloss level between an access node and a neighboring access node, an estimation of an uplink sounding pathloss level between the access node and a terminal, said terminal being connectable to the access node and the neighboring access node, a comparison of the estimated uplink sounding pathloss level and the retrieved average handover pathloss level, and an enabling of a switch-on of the access node from an inactive state in which a transmitter is switched off to an active state in which the transmitter is switched on, when the estimated uplink sounding pathloss level is smaller than the retrieved average handover.

Abstract: Methods and apparatus are provided for directing a beam towards a receiving device in the presence of interference. A beam transmitted by a transmission source is received at a receiving device. The received beam is affected by an interference signal from an interfering source. The receiving device computes a covariance matrix that represents a channel estimate associated with the interfering source. The receiving device modifies a predetermined sounding signal based on the covariance matrix for transmission to the transmission source. The receiving device causes the transmission source to estimate an equivalent channel matrix based on the predetermined sounding signal and the modified predetermined sounding signal. The equivalent channel matrix represents the channel estimate associated with the interfering source and a channel estimate associated with the transmission source.

Abstract: A ground control apparatus is provided with: a train speed calculation unit that calculates train speed by using train present track position information notified from a train; a predicted passage time calculation unit that calculates a predicted passage time at a previously-stored H/O point based on the H/O point, the calculated train speed, and brake performance; a wireless CH reservation unit that performs processing of reserving a wireless CH of a H/O target wireless base station based on usage of a wireless channel allocated to the H/O target wireless base station and the calculated predicted passage time; and a wireless CH reservation result notification unit that notifies a reservation result of the wireless CH reservation unit to a H/O source wireless base station.

Abstract: Disclosed are an adaptive pilot symbol assignment method that flexibly controls the number of transmit antennas according to each user's moving speed, channel status, or user request, and assigns proper pilot symbols in the downlink of an OFDMA (Orthogonal Frequency Division Multiplexing Access) based cellular system; and a sub-carrier allocation method for high-speed mobile that allocates some sub-carriers to assign proper pilot symbols for ultrahigh-speed mobile users, and the rest of the sub-carriers to the other users to assign proper pilot symbols to the users, on the assumption that the ultrahigh-speed mobile users have a traffic volume almost insignificant to the whole traffic volume.