Abstract: Terminals and base stations belonging to service areas 100 to 102 of plural radio operators periodically measure a radio-link quality and an availability ratio of a radio link to notify them to a radio-resource management server 40. The server 40 alters a frequency of the base station, and a transmitted-power quantity of the base station and the terminal based on these measured results to improve the radio-link quality, and reduces interference with a neighboring radio system. When a load is concentrated on a network of a specific radio operator, an instruction of handover is given to the terminal from the server 40 to realize a load distribution within the radio operator, and between the radio operators.

Abstract: A method of controlling handover of a mobile station (5) from a first cell (61) to a second cell (62) includes adjusting a handover parameter so that, when radio quality of the first cell (61) at a position of a mobile station (5) is a first level, lag time from when a handover initiation condition is satisfied to when the handover is initiated is shorter than when the radio quality of the first cell is a second level that is higher than the first level. As a result, for example in HCS (HetNet), handover failures and ping-pong/rapid handovers can be reduced, and a mobile station expected to stay in a small-scale cell for at least a certain period of time can be efficiently accommodated in a small-scale cell.

Abstract: A handover failure detection device (121) detects at least one of handover failure types regarding outgoing handover from a first cell (131) managed by a first base station (111) by observing: (a) presence/absence of reception by the first base station (111) of an acknowledgment response to a handover command regarding first handover of a mobile terminal (101) from the first cell (131) to a second cell (132) managed by a second base station (112); and (b) presence/absence of a request for connection re-establishment from the mobile terminal (101) to the first cell (131), the request occurring after initiation of the first handover. As a result, it contributes to improvement of handover failure detection or reduction of handover failure in a situation where exchange of information between base stations is restricted.

Abstract: The present invention is applicable to a wireless communication system provided with mobile terminals and base stations that manage cells to which the mobile terminals are connected. The wireless communication system of the present invention has a new cell detection unit that detects, from among neighbor cells which are adjacent to the cells to which the mobile terminals are connected, new cells that have newly started or whose operation has resumed or whose geographical range has changed, and a neighbor cell list generation unit which preferentially registers new cells that have been detected by the new cell detection unit in neighbor cell lists in which are registered neighbor cells that are candidates for handover destinations of the mobile terminals.

Abstract: Disclosed is a communication system in which information about the number of active users in each cell can be shared between base stations. A communication system according to the present exemplary embodiment includes a first base station controlling a first cell and a second base station connected to the first base station through an inter-base-station interface, wherein the first base station transmits operation information on the first cell to the second base station through the inter-base-station interface, wherein the operation information on the first cell includes information about a load on the first cell and information about the number of active users in the first cell.

Abstract: It is an object of the present invention to provide a communication system that makes it possible to designate, from among a plurality of first network nodes managed by a management device, a first network node that will acquire operation information on a second network node managed by another management device. A communication system according to the present exemplary embodiment includes a plurality of first network nodes, a management device managing the plurality of first network nodes, and a second network node managed by another management device different from the management device, wherein the management device selects, from among the plurality of first network nodes, a designated network node that will acquire operation information on the second network node, and the designated network node acquires operation information from the second network node and transmits the operation information to the management device.

Abstract: A radio communication system and a handover control method are provided that can reduce abnormal disconnections of communication attributable to handover to from another cell an own cell. Provided are a handover suppression section (102) that, when receiving from a base station (30A) managing a first cell (35A) a request for handover to a second cell (35B), suppresses the handover in accordance with the degree of handover suppression, a handover failure detection section (13) that detects a handover failure caused by the handover suppression, and a handover suppression optimization section (203) that adjusts the degree of handover suppression based on the rate of handover failure occurrence.

Abstract: In order to effectively determine an optimized radio resource, a radio communication system (100) includes a plurality of first base stations (111) and a plurality of first mobile stations (112) respectively connected to the plurality of first base stations (111). In the radio communication system (100), there are included calculation means (103) for calculating a statistic (130) by aggregating interference levels of radio waves between the plurality of first base stations (111) and second mobile stations (122) connected to a second base station (121) that forms a second cell (120) larger than a first cell (110) formed by each of the first base stations (111); and determination means (104) for determining, based on the statistic (130), a radio resource to be used by the plurality of first base stations (111) or the plurality of first mobile stations (112).

Abstract: To provide a base station in which an electric power consumed in the base station can be suppressed and an electromagnetic wave interference between the base stations can be avoided, a method for controlling a base station, a control program, and a mobile station. The base station includes storage means, traffic history generation means for measuring a traffic of the base station for each unit time and storing it in the storage means as a traffic history, and control means for controlling transmission of a control signal based on the traffic history.

Abstract: A radio parameter control apparatus decides a radio parameter from which a throughput of UE is improved. A radio parameter control apparatus includes: a radio quality prediction unit (12) that predicts radio quality of a radio terminal due to change of a radio parameter of a radio cell; a resource-allocated number-of-communications prediction unit (13) that predicts the number of communications considered as allocation targets of radio resources in a radio cell due to the change of the radio parameter; a communication quality prediction unit (14) that predicts communication quality due to the change of the radio parameter based on a prediction result of the radio quality and a prediction result of the number of communications; and a radio parameter decision unit (15) that decides a radio parameter by which improvement of communication quality is predicted based on the predicted communication quality.

Abstract: In a wireless cell, the potential deterioration in quality is efficiently detected when the indication of abnormalities is weak. Provided are a step of calculating one or more radio qualities for each coverage area of a wireless cell; a step of measuring one or more network statistical qualities for each coverage area of the wireless cell; a step of making a pair of each network statistical quality and one or more radio qualities for each coverage area of each wireless cell; and a step of calculating, based on the pairs of each network statistical quality and one or more radio qualities for the coverage areas of the wireless cells, the correlation between each network statistical quality and one or more radio qualities.

Abstract: Terminals and base stations belonging to service areas of plural radio operators periodically measure a radio-link quality and an availability ratio of a radio link and provide notification to a radio-resource management server. The server alters a frequency of the base station, and a transmitted-power quantity of the base station and the terminal based on these measured results to improve the radio-link quality, and reduce interference with a neighboring radio system.

Abstract: Terminals and base stations belonging to service areas of plural radio operators periodically measure a radio-link quality and an availability ratio of a radio link to notify them to a radio-resource management server. The server alters a frequency of the base station, and a transmitted-power quantity of the base station and the terminal based on these measured results to improve the radio-link quality, and reduces interference with a neighboring radio system. When a load is concentrated on a network of a specific radio operator, handover instruction is given to the terminal from the server to realize a load distribution. When the server detects excessive radio interference between the radio operators, it notifies occurrence of a fault, an interference quantity, a quantity of the transmitted power that the base station should attenuate, and the frequency that the base station should alter to the radio operator that becomes an interference source.

Abstract: A mobile terminal includes a measuring unit that measures at least the moving speed of the self terminal and communication quality of wireless communication, and a communication unit that transmits terminal information including moving speed information and communication quality information. A quality monitoring apparatus (90) includes a terminal information collection unit (901) that collects the terminal information from at least one mobile terminal, and a terminal information classification unit (903) and a quality analyzing unit (904) that monitor communication quality in a predetermined target area for each moving speed range of the mobile terminal based on the collected terminal information.

Abstract: A base station includes a radio communication unit, a resource adjustment unit, a resource division unit and a detection unit. The resource adjustment unit determines radio resources to be allocated to a downlink communication from a radio resource region shared with another base station. The resource division unit limits, to a first radio resource segment which is a part of the radio resource region, radio resources in response to estimating that communication quality of the downlink communication using the limited first radio resource segment is improved over the communication quality of the first downlink communication when using the entire range of the radio resource region that is shared with the other base station. The detection unit detects execution of resource division by the other base station for limiting radio resources used for another downlink communication between the other base station and a mobile station to a second radio resource segment.

Abstract: A network management apparatus in a mobile communication network holds a communication quality index in a normal operation and periodically receives input of a communication quality measurement result from a radio base station control apparatus. When a connection failure count f with respect to a connection request count a of each radio cell is obtained as a measurement result, letting p0 be the call loss rate in the normal operation, an upper probability B of a binomial distribution representing the connection failure count becomes larger than f is obtained (step 524). The negative logarithm of the upper probability B is obtained as the score of the degree of abnormality (step 525). Anomaly of communication is detected when the score of the degree of abnormality exceeds a predetermined threshold value (steps 526 and 527). After that, maintenance control is executed in accordance with the calculated score of the degree of abnormality, thereby appropriately avoiding a fault of the communication system.

Abstract: A neighbor list optimization unit (11) performs optimization of a neighbor list that is wirelessly transmitted by a base station (2) that manages an objective cell (61). The neighbor list optimization unit (11) includes a cell selection unit (110). The cell selection unit (110) selects, based on cell types defined according to a difference in cell sizes, a plurality of registered cells to be registered in the neighbor list from a plurality of other cells (62) than the objective cell (61). Accordingly, for example, it is possible to perform neighbor list optimization suitable for a heterogeneous network (HetNet) environment in which different types of cells having different sizes in coverage (cell sizes) are adjacently arranged.

Abstract: A method of controlling handover of a mobile station (5) from a first cell (61) to a second cell (62) includes adjusting a handover parameter so that, when radio quality of the first cell (61) at a position of a mobile station (5) is a first level, lag time from when a handover initiation condition is satisfied to when the handover is initiated is shorter than when the radio quality of the first cell is a second level that is higher than the first level. As a result, for example in HCS (HetNet), handover failures and ping-pong/rapid handovers can be reduced, and a mobile station expected to stay in a small-scale cell for at least a certain period of time can be efficiently accommodated in a small-scale cell.

Abstract: A nonvolatile semiconductor memory includes a memory cell transistor including a first floating gate electrode layer formed on a first tunneling insulating film, a first inter-gate insulating film, first and second control gate electrode layers, and a first metallic silicide film; a high voltage transistor including a high voltage gate electrode layer formed on a high voltage gate insulating film, a second inter-gate insulating film having an aperture, third and fourth control gate electrode layers, and a second metallic silicide film; a low voltage transistor including a second floating gate electrode layer formed on a second tunneling insulating film, a third inter-gate insulating film having an aperture, fifth and sixth control gate electrode layers, and a third metallic silicide film; and a liner insulating film directly disposed on source and drain regions of each of the memory cell transistor, the low voltage transistor, and the high voltage transistor.

Abstract: A non-volatile semiconductor storage device includes: a semiconductor substrate; a semiconductor layer formed on the semiconductor substrate; a first device isolation/insulation film formed in a trench, the trench formed in the semiconductor layer, with a first direction taken as a longitudinal direction; a device formation region formed by separating the semiconductor layer by the first device isolation/insulation film with the first direction taken as a longitudinal direction; and a memory transistor disposed on the device formation region. The first device isolation/insulation film and the device formation region have an impurity of a first conductivity type. An impurity concentration of the impurity of the first conductivity type in the first device isolation/insulation film is higher than that in the device formation region.