Patent application number | Description | Published |
20080279124 | OFDM WIRELESS COMMUNICATION METHOD AND WIRELESS COMMUNICATION APPARATUS - In a wireless communication system wherein at least two communication units employ the TDD wireless communication method based on OFDMA, an OFDM wireless communication method and a wireless communication apparatus are disclosed. The first communication unit transmits a pilot signal over the whole subband zone configured of divisions of a predetermined system band. The second communication unit having a plurality of antennas estimates a propagation path of the subchannels constituting continuous frequency blocks making up a subband from the pilot signal received. The second communication unit determines the array weight used at the time of signal transmission to the first communication unit using the estimation result. | 11-13-2008 |
20090210766 | WIRELESS COMMUNICATION SYSTEM, TERMINAL AND BASE STATION - A non-terminated packet is transmitted, by utilizing a spatial layer responded with an ACK, which is assumed as a released layer. Alternatively, a non-terminated packet is transmitted by using a released layer and an original spatial layer in combination. Alternatively, a new packet is transmitted in a released layer by utilizating time till termination of transmission of a non-terminated packet. A wireless communication system effectively utilizing a released layer, a terminal and a base station. | 08-20-2009 |
20090213743 | NOISE POWER ESTIMATION APPARATUS AND METHOD - A pilot signal is estimated by using the sampling theorem to estimate noise power in a stable manner without depending on the signal to noise ratio. A pilot signal estimation section obtains an estimated pilot signal by using the sampling theorem according to a plurality of received pilot signals sampled in the frequency domain by a sampling processor. A noise power estimation section estimates noise power by applying statistical averaging to the difference between the received pilot signal received from the sampling processor and the estimated pilot signal received from the pilot signal estimation section. | 08-27-2009 |
20090232236 | BASE STATION AND MOBILE STATION FOR OFDMA CELLULAR SYSTEM - In a cellular radio communication system, a base station or a mobile station has a TA (Time Alignment)-range-out detection function, so that when a TA-range-out state that is unable to compensate with a guard interval is detected, the transmission condition of an uplink signal at the mobile station is changed by the mobile station autonomously or by the base station and the mobile station cooperatively. | 09-17-2009 |
20090253461 | BASE STATION EQUIPMENT - A base station equipment determines, based on a specified condition, whether or not a wireless terminal exists in the vicinity thereof, and then if it exists in the vicinity, the base station equipment transmits information indicating that the base station equipment is ready to communicate with the wireless terminal. | 10-08-2009 |
20090300454 | TRANSMISSION APPARATUS, ACCESS POINT AND SYMBOL TRANSMISSION METHOD - In a transmission apparatus in a MIMO-OFDM communication system employing a cyclic diversity, a cyclic delay controller sets plural delay magnitudes different for respective antennas, in cyclic delayers for each predetermined timing. The cyclic delayers receive symbols subjected to orthogonal frequency division multiplexing, for the respective ones of plural allotted antennas. Besides, the cyclic delayers bestow cyclic delays on the individual symbols of the respective antennas in accordance with plural set delay magnitudes. The symbols cyclically delayed are outputted from the antennas. As the delay magnitudes, a first delay magnitude at a first transmission timing and a second delay magnitude at a second transmission timing are different for one antenna, and the delay magnitudes differ in the respective antennas for one transmission timing. Thus, in a MIMO-OFDM transmission scheme, a frequency diversity and a time diversity are enhanced to heighten a retransmission efficiency in a data retransmission mode. | 12-03-2009 |
20100046359 | Wireless Terminal, Base Station and Channel Characteristic Estimating Method - In a wireless communication system based on an OFDM access system, when forgetting averaging channel estimation is performed, there occurs a phase difference between a present channel estimated value and a past estimated value due to a change of FFT operation timing at a reception side. The error of the channel estimated value caused by the phase difference is corrected. A synchronization catching/tracking unit to determine an operation timing of an FFT from a received signal is provided, and an FFT operation timing difference acquisition section to grasp a change of the operation timing of the FFT generated by the synchronization catching/tracking unit is provided. Based on an FFT operation timing change amount as an output of the FFT operation timing difference acquisition section, a rotation operation is performed on a propagation path estimated result stored in a channel estimation section to estimate a propagation path from a received pilot signal, so that the error of the channel estimated value is corrected. | 02-25-2010 |
20100272018 | WIRELESS COMMUNICATION SYSTEM AND WIRELESS COMMUNICATION METHOD, AND BASE STATION APPARATUS - The present invention pertains to the technology for avoiding interference between adjacent frequencies occurring on cell boundaries or sector boundaries in a mobile wireless communication system using an OFDMA (Orthogonal Frequency Division Multiple Access) scheme. There are a single sector mode of no collaboration between sectors; a sector selection mode of collaborating between sectors to transmit with a specified frequency resource from only one sector, and a collaboration mode of collaborating between sectors to transmit signals from both sectors. Any of the three modes is selected on the basis of measurement results of RSRP (Reference Signal Received Power) reported from a mobile station. | 10-28-2010 |
20100290413 | RADIO BASE STATION APPARATUS - A DSP checks the traffic on a control channel transmitted to each terminal, and obtains a total of traffic on the control channel for each remote radio unit. The DSP transforms a correlation matrix calculated in an analysis section to a partial orthogonal matrix subjected to partial orthogonalization. The DSP divides one or more remote radio units into the groups in accordance with the sequence of rows or columns of the partial orthogonal matrix so that the total traffic for each group in which the total of traffic is added for one or more remote radio units within the group may be less than or equal to a predetermined threshold, and stores the identification number of the remote radio unit for each group in a memory. | 11-18-2010 |
20100322107 | WIRELESS COMMUNICATION NETWORK, METHOD OF GENERATING NEIGHBOR LIST IN THE WIRELESS COMMUNICATION NETWORK, AND CONTROL DEVICE THEREFOR - In a wireless communication system, a base station control device has following two steps on the basis of latitude/longitude information obtained from a GPS, that is, a first step of recognizing, from the positional information obtained from the GPS, the fact that base stations in new and old systems are installed at the same location, and a second step of linking a neighbor list of the old system to a neighbor list of the new system with use of the result of the first step. | 12-23-2010 |
20110038249 | TIMING ADJUSTMENT METHOD, RECEIVING STATION, AND TRANSMITTING STATION IN WIRELESS COMMUNICATION SYSTEM, AND WIRELESS COMMUNICATION SYSTEM - A discontinuous change in a transmission timing in a time domain, which is caused by a transmission timing adjustment processing of an OFDMA uplink or the like, brings about a discontinuous rotation of a signal phase in a frequency domain, resulting in reduced communication quality. A wireless communication system of the present invention allows the signal phase of the frequency domain in a receiving station to be continuous before and after the timing adjustment processings by controlling a signal sequence in a transmission signal after conversion in the time domain in synchronization with the timing adjustment processing. | 02-17-2011 |
20110085448 | WIRELESS COMMUNICATION SYSTEM, WIRELESS BASE STATION APPARATUS, AND WIRELESS COMMUNICATION METHOD - Random beams and FFR are used in combination, frequencies are grouped into a zone associated with the center of a cell and a zone associated with the border of the cell, and the random beams are applied only to the zone associated with the border of the cell. Since the number of resources to be allocated to the random beams decreases, a terminal lying on the border of the cell can reduce overhead. Using the zone associated with the center of the cell, beam scheduling can be freely performed within the cell. | 04-14-2011 |
20110092238 | WIRELESS COMMUNICATION SYSTEM, WIRELESS COMMUNICATION METHOD, AND BASE STATION - In a wireless communication system having a plurality of base stations and a control station controlling the plurality of base stations, the control station allocates, to the plurality of base stations, antenna patterns associated with directivity patterns for each of a plurality of frequency bands that can be utilized by the respective base stations and if it transmits, to respective ones of the plurality of base stations, parameters for associating the allocated antenna patterns with directivity patterns for each of the plurality of frequency bands; and the plurality of base stations associate the directivity patterns with the plurality of frequency bands on the basis of the parameters received from the control station and, in accordance with the associated directivity patterns, transmit signals to the antenna and receive signals from the antenna. | 04-21-2011 |
20110158187 | RADIO RESOURCE ASSIGNMENT METHOD AND BASE STATION DEVICE - A radio resource assignment method, wherein it is determined at a predetermined timing whether a cell is congested or not; the determination result is notified to adjacent base stations; results of determination of congestion or non-congestion received from adjacent base stations are stored; when it is determined that the base station is not congested, a check is made whether or not the adjacent base stations are congested; when the adjacent base stations are congested, the use of the resource blocks is restricted to decide an empty resource block; and information on the decided resource block is notified to the adjacent base stations. When it is determined that the base station is congested, the information on the empty resource blocks received from the adjacent base stations is checked, and the empty resource blocks are assigned to mobile terminal devices within the cell. | 06-30-2011 |
20110158190 | CELLULAR RADIO COMMUNICATION SYSTEM, RADIO BASE STATION APPARATUS AND RADIO TERMINAL UNIT - In a cellular radio communication system including of multi-antenna base stations, to make effective use of the reduced interference in supposing the use of beam form and avoid the interference in an adjacent station even if a space multiplex and the beam form are mixed. Frequencies intended for the cell edge in an FFR are classified into frequencies for space multiplex and a frequency for beam form. Thereby, a frequency at which the interference is reduced by the beam form is fixed. A frequency intended for the cell center is in a frequency band and signals are transmitted from three base stations. | 06-30-2011 |
20110223962 | WIRELESS COMMUNICATION SYSTEM AND METHOD, AND BASE STATION APPARATUS - In a conventional cellular wireless communication system that included a plurality of base station apparatuses having a plurality of antennas, just two antennas were used for simultaneous transmission by transmission diversity, and the antenna usage efficiency was low. According to the present invention, a free transmission diversity antenna for transmission to the edge of a cell is used to send a signal to a terminal located around the center of the cell without causing interference to a terminal located around the edge of the cell. The two terminals located around the edge of the cell and around the center of the cell are paired for simultaneous signal transmission. A signal directed to the edge of the cell and a signal directed to the center of the cell are sent with greatly different transmission power. This reduces the interference caused by the signal directed to the center of the cell to an insignificant level for the terminal located around the edge of the cell. The terminal located around the edge of the cell does not appear to be affected by interference from signal transmission to the center of the cell and does not have to always use four antennas. | 09-15-2011 |
20110255519 | Signal Mapping Method and Communication Device - Ameliorate deterioration in quality of communication caused by intercell interference with respect to a multicarrier communications protocol, such as OFDM. A method of positioning an error correction-coded signal is changed with a data symbol that is transmitted simultaneously with a pilot signal and a data symbol that is not simultaneous with the pilot symbol. Else, a modulation protocol is changed with a data symbol that is transmitted simultaneously with a pilot signal and a data symbol that is not simultaneous with the pilot symbol. It would further be permissible to lower either a signal amplitude or a power level of a data symbol that is transmitted simultaneously with a pilot signal. | 10-20-2011 |
20120094702 | RADIO COMMUNICATION SYSTEM, RADIO COMMUNICATION METHOD AND BASE STATION - When DFFR is performed in a heterogeneous environment in which a pico base station coexists in the area of a macro base station and when the pico base station judges that, based on the received-signal quality report result from a mobile terminal, the macro base station causes interference to the pico base station, the pico base station reports an interference power threshold to be notified to the macro base station based on the transmission power setting value of the macro base station, the transmission power setting value of the pico base station, and the estimated interference amount calculated from the scan report result. The macro base station transmits a result of comparison between the transmission powers of multiple frequency resources and the interference power threshold, to the pico base station and the pico base station selects a frequency resource, unlikely to be affected by interference. | 04-19-2012 |
20120094703 | RADIO BASE STATION, RADIO COMMUNICATION SYSTEM AND INTERFERENCE NOTIFYING METHOD IN RADIO COMMUNICATION SYSTEM - A radio communication system is provided in which, based on a measurement condition and neighbor information specified by a base station to which a mobile terminal is connected, the mobile terminal measures the reception quality of the neighboring base stations included in the neighbor information and, when a transmission request is received from the connected base station, transmits the measurement result to the connected base station. In this radio communication system, the base station transmits neighbor information, which specifies the base stations for which interference measurement is to be performed, and a measurement result transmission request to the mobile terminal at a predetermined time for measuring the interference of neighboring base stations and, in response to it, the mobile terminal transmits the measurement result of the base stations, specified by the base station for measuring the interference, to the base station. | 04-19-2012 |
20120120876 | BASE STATION AND MOBILE STATION FOR OFDMA CELLULAR SYSTEM - In a cellular radio communication system, a base station or a mobile station has a TA (Time Alignment)-range-out detection function, so that when a TA-range-out state that is unable to compensate with a guard interval is detected, the transmission condition of an uplink signal at the mobile station is changed by the mobile station autonomously or by the base station and the mobile station cooperatively. | 05-17-2012 |
20120121045 | MIMO RECEIVING METHOD - To provide a space multiplex signal detection circuit capable of obtaining an excellent error rate characteristic by suppressing an increase in the circuit scale if when a modulation multivalued number is particularly increased in the case of receiving a signal subjected to space multiplexing to detect the signal. SOLUTION: A transmission signal candidate narrow-down circuit | 05-17-2012 |
20120140658 | WIRELESS BASE STATION FOR CONTROLLING ANTENNA TRANSMISSION POWER - Provided is a wireless communication system which includes a wireless communication unit using plural frequency bands and plural antennas. The system changes the transmission power of each antenna, based on the interference of each of the frequency bands from the neighbor base station along the antenna direction. The system estimates the number of antennas necessary for transmission in response to a user requirement, and determines a necessary antenna in accordance with the antenna direction in which the terminal is located, and further changes the transmission power of each antenna. | 06-07-2012 |
20120170623 | RADIO SIGNAL PROCESSING METHOD AND RADIO COMMUNICATION APPARATUS - Disclosed is a radio communication apparatus for transmitting signals in the form of the MIMO comprises a reception signal processing unit for performing processing of signals received from a plurality of antennas, a transmission signal processing unit for performing processing of signals to be transmitted from the plurality of antennas, a control unit for controlling the whole of apparatus and a memory for storing a transmission/reception signal processing program and transmission/reception signal processing information. The reception signal processing unit corresponds to a plurality of kinds of reception signal processing schemes, and the control unit allots, in accordance with conditions of a radio communication apparatus opposing through propagation paths and with processing conditions in reception signal processing, one of the plurality of reception signal processing schemes as a reception signal processing method adapted to process signals received from the opposing radio communication apparatus. | 07-05-2012 |
20130003669 | TRANSMISSION POWER ADJUSTMENT METHOD IN WIRELESS COMMUNICATION SYSTEM AND BASE STATION - Necessary transmission power of terminals is secured while suppressing total transmission power in base station, so that FFR technology is realized with high frequency utilization efficiency to thereby realize both of compactness of base station and increase of communication capacity. Frequency resource is divided into frequency for boundary area of cell and frequency for central area of cell. Transmission power per unit frequency is fixed in the frequency for boundary area of cell and is set to be variable in the frequency for central area of cell. Transmission power per unit frequency is adjusted so as to satisfy necessary power of terminals connected to frequency for central area of cell. When it is judged that total transmission power of base station exceeds prescribed value, terminal is moved from central area to boundary area of cell, so that total transmission power is suppressed to be equal to or smaller than standard. | 01-03-2013 |
20130005403 | RADIO COMMUNICATION SYSTEM, RADIO COMMUNICATION METHOD, BASE STATION DEVICE AND TERMINAL DEVICE - A base station broadcasts a message saying that transmittable ranging codes are limited by antenna IDs to limit antennas and the ranging codes to be searched, thereby reducing a processing load of the search. In a cellular radio communication system in which a base station device is connected to plural antennas, and antenna IDs for identifying the antennas are transmitted from the respective antennas, the base station device broadcasts a message saying that a group of ranging codes transmittable by a terminal device is limited by the antenna IDs, the terminal device receives the message, identifies the antenna ID, selects the ranging code from the group of the ranging codes corresponding to the antenna ID, and transmits the selected ranging code. | 01-03-2013 |
20130201896 | WIRELESS COMMUNICATION SYSTEM - The present invention is directed to achievement of a data transmission control to cause base stations to cooperate with one another, taking into account efficient use of radio resources. A wireless communication system, which is an aspect of the present invention, includes: a first base station; a second base station connected via a wired network; and a wireless communication terminal that conducts at least one of single data transmission in which a single base station transmits data and cooperative data transmission in which a plurality of base stations cooperate to transmit data. The base stations notify the wireless communication terminal of a condition indicating a case where the cooperative data transmission can be performed. If the communication quality of the propagation path meets the condition, the wireless communication terminal transmits, to the base stations, information that is required for the cooperative data transmission. | 08-08-2013 |