Patent application number | Description | Published |
20110211519 | WIRELESS COMMUNICATION SYSTEM, BASE STATION AND NETWORK CONTROL APPARATUS - In a time slot in which a first base station for performing a multicast transmission executes the multicast transmission, a second base station which does not perform the multicast transmission does not perform a unicast data transmission. The time slot in which the first base station performs the multicast transmission is notified to the second base station from a multicast control apparatus for performing scheduling of the multicast transmission to the first base station. Information to receive the multicast transmission is notified from the second base station to a terminal connected to the second base station. | 09-01-2011 |
20110211560 | MOBILITY CONTROL METHOD MITIGATING INTER CELL INTERFERENCE AND BASE STATIONS WHICH ADOPT THE METHOD - Interference applied to neighbor cells during terminal handovers can be reduced in wireless communication systems containing base stations having different cell sizes. A serving cell makes handover judgment criteria easier based on pre-acquired cell size information on its own cell and cell size information of neighbor cells in order to facilitate terminal handovers from a base station with a large cell size to a base station with a small cell size. The serving cell finds evaluation function values based on the propagation state (e.g. reference signal received power) between the terminal and target cell, and the interference and load information exchanged between the base stations, and selects the terminal for handover by comparing the evaluation function value with the handover criteria value. The system selects a target cell having a good effect in lowering interference such as a cell with large reference signal received power acquired from a terminal, to serve as the handover destination. | 09-01-2011 |
20110212744 | TRANSMIT POWER CONTROL METHOD FOR RADIO COMMUNICATION SYSTEM AND RADIO BASE STATION DEVICE - A communication device includes pilot signal sending part and transmit power control part and holds a criterion value indicating target channel quality for mobile stations within the area covered by the base station. It creates quality data from reports from one or plural mobile stations, stores the quality data, creates a first representative value indicating average channel quality for the mobile station(s) from the stored quality data, and changes the transmit power depending on the result of comparison between the first representative value and the criterion value. It creates a second representative value indicating distribution of low channel quality from the stored quality data and updates the criterion value depending on the result of comparison between the second representative value and the criterion value. | 09-01-2011 |
20110244866 | WIRELESS COMMUNICATION SYSTEM AND LOAD BALANCING AWARE HANDOVER METHOD THEREFOR - An object of the invention is to provide a wireless communication system in which the load of each cell and interference between cells are taken into account. In a handover-candidate base station and a handover-source base station, parameters for interference-reducing scheduling and handover facilitating processing are adjusted based on the mutual load information. When the handover-candidate base station, to be used for load balancing, is a large-diameter cell, transmit power control and frequency scheduling are adjusted by taking account of the load state at a cell edge. When the handover-source base station has a small-diameter cell, the number of terminals to be handed over is adjusted by taking account of the load state of the handover-candidate base station. Thus, both of interference control and load balancing are achieved. | 10-06-2011 |
20110310758 | Method of Resource Assignment for Radio Communication System and Base Station Apparatus - A method for assigning resources of a radio communication system that is aimed at relaxing interference between cells and that is applicable even in the case where femtocell base stations are installed within a macrocell base station area, and a radio base station apparatus. A transmit power limitation that limits an allocatable resource for each subband consisting of one or plural sub-carriers is decided, resource assignment is preformed on a mobile terminal on a subband-by-subband basis by a scheduler so that the transmit power limitation may be satisfied, and the transmit power limitation is altered based on an estimation result of an interference quantity from surrounding cells. | 12-22-2011 |
20110317742 | BASE STATION - A cellular radio communication system includes a first mobile terminal, a base station that performs radio communication with first mobile terminals, a second mobile terminal, and a second base station that performs radio communication with second mobile terminals. In the downlink communication, the base station selects a high data rate mode when the radio interference from the base station to the second mobile terminals that are located close to an edge of a communication area of the second base station is small. The base station selects an interference mitigation mode in the downlink communication when the radio interference from the base station to the second mobile terminals that are located close to the edge of the communication area of the second base station is large. Thus, inter-cell interference control can be performed in collaboration with base stations in the radio communication system without having communication interface between the base stations. | 12-29-2011 |
20120028630 | Base Station and Cellular Wireless Communication System - A femtocell base station collects the terminal distribution within the cell and selects terminals to represent the cell-center and the cell-edge from among the terminals within the cell. The femtocell base station also calculates maximum transmit power for the respective the cell-center and cell-edge terminals allowable by the macrocell base station. The femtocell base station sets the respective transmit power of the cell-center and the cell-edge in a range that will not exceed the maximum transmit power, adjusts the transmit power control parameter to allow control by the terminal at the power value that was set, and notifies the terminal. Communication with high throughput can in this way be attained for terminals in cells within the femtocell base station during uplink communications to the femtocell base station, and interference applied to the terminals in the macrocell base station can be suppressed. | 02-02-2012 |
20120281569 | BASE STATION, INTERFERENCE CONTROL METHOD AND RADIO COMMUNICATION SYSTEM - Timing division multiplexing is conducted between the cells to avoid intercell interference. Transmission timing in a time slot pattern has a given interval. A base station determines the transmission timing based on measured uplink interference power. For example, an uplink time slot pattern in which the measured uplink interference power is smaller is selected. A downlink time slot pattern is assigned so that a response to HARQ is returned at that timing. If traffic is busy, additional time slot pattern may be assigned. In determination of the traffic volume, for example, the queued buffer size, the number of connected terminals, or the number of connections to a higher-level device can be used. Assignment timing can be an initial setup time, or a fluctuation detection time of a channel which can be realized by collection of report information on a downlink communication quality, periodic monitor of uplink interference information. | 11-08-2012 |
20130244658 | HANDOVER MANAGEMENT APPARATUS, BASE STATION, AND HANDOVER MANAGEMENT METHOD - In femtocell operation, when a wireless communication terminal whose ID is not registered (ID unregistered terminal) has entered a femtocell's area, the disclosed invention prevents interference between the femtocell and the ID unregistered terminal and interference between the ID unregistered terminal and an ID registered radio communication terminal and prevents a decrease in the throughput of the femtocell and these terminals. In a radio coverage area formed by a radio base station, if a drop of received power from a radio communication terminal occurs and the frequency of reporting the ID of the base station now communicating with the terminal has become less than a given value, it is decided that the terminal is located indoors. For the terminal, if its handover to a femtocell was found to be rejected by MME, the terminal is temporarily permitted to be handed over to a femtocell. | 09-19-2013 |