Abstract: A wireless terminal (1A) receives a discovery signal (201) wirelessly transmitted from another wireless terminal (1B) via device-to-device (D2D) communication, and transmits a discovery report (202, 302) to a network (2, 3) via cellular communication (101). The discovery report indicates at least one of: (a) an identifier of the other wireless terminal (1B); (b) an identifier(s) of one or more D2D communication pairs to which the other wireless terminal (1B) belongs; (c) an identifier of a base station or a cell with which the other wireless terminal (1B) is associated; (d) received power of a discovery signal from the other wireless terminal (1B); and (e) the number of detections of the discovery signal from the other wireless terminal (1B). It is thus possible to provide a discovery report containing contents suitable for use in a network.

Abstract: A radio terminal (2) is used in a radio communication system (100) and communicates with a radio station (1). The radio terminal (2) includes a measurement unit (20). The measurement unit (20) operates to perform, using a terminal measurement procedure for executing a first terminal measurement corresponding to radio access technology applied to the radio communication system (100), a second terminal measurement of a shared frequency shared by a plurality of radio systems including the radio communication system (100).

Abstract: A radio terminal (1) selects, from a resource pool in a discovery period, NTX sets of resource blocks for NTX transmissions of a discovery signal based on a first value n1 that is a resource value autonomously selected by the radio terminal (1) or is a parameter received from a base station (2). A frequency domain shift from a second resource block set used in (j?1)th transmission (j is an integer no less than 2) to a first resource block set used in j-th transmission of the discovery signal in the discovery period depends on at least one of the first value n1 and a frequency domain position of the second resource block set in the resource pool. It is thus, for example, possible to attenuate decline in reception quality of a discovery signal due to interference resulting from In-Band Emissions (IBE) when direct discovery of D2D communication is performed.

Abstract: A D2D communication control apparatus (10) according to the present invention includes: a communication unit (11) configured to receive determination information that can be used to determine whether a plurality of radio terminals are capable of performing direct communication with another radio terminal; and a selection unit (12) configured to select, in a situation in which a first radio terminal included in the plurality of radio terminals is performing D2D communication with a relay radio terminal that performs cellular communication with a network, a radio terminal in which the determination information between the radio terminal and the relay radio terminal satisfies a predetermined condition among radio terminals capable of performing D2D communication with the first radio terminal, as a preliminary relay radio terminal.

Abstract: A relay selecting apparatus (1, 3 or 5) is configured to select at least one specific relay terminal (2) suitable for a remote terminal (1) from among one or more relay terminals (2) based on a selection criterion that considers a time variation of a device-to-device (D2D) link quality between the remote terminal (1) and each of the one or more relay terminals (2). In this way, it is possible to contribute to improving a relay selection so as to provide a stable relay quality.

Abstract: A radio terminal (1) selects, from a resource pool in a discovery period, NTX subframes for NTX times of transmission of a discovery signal in the discovery period based on a first value n1 of a resource value autonomously selected by the radio terminal (1) or a first value n1 of a parameter received from a base station (2). The NTX subframes selected based on the value n1 are selected so as to share at least one common subframe with NTX subframes selected based on a second value, different from the first value n1, and so as to include at least one subframe different from any of the NTX subframes selected based on the second value. It is thus, for example, possible to attenuate decline in reception quality of a discovery signal due to interference resulting from In-Band Emissions (IBE) when direct discovery of D2D communication is performed.

Abstract: A D2D communication control apparatus (10) according to the present invention includes: a communication unit (11) configured to receive determination information that can be used to determine whether each of a plurality of radio terminals is capable of performing device-to-device (D2D) communication with another radio terminal; and a selection unit (12) configured to select, using the determination information between radio terminals that may operate as relay radio terminals, a candidate for a relay radio terminal that relays the communication between one of the plurality of radio terminals and a network, the relay radio terminal candidate transmitting a response signal in response to a first discovery signal transmitted from one of the radio terminals by performing D2D communication with the one of the plurality of radio terminals and performing cellular communication with the network.

Abstract: A base station (2) is configured to schedule radio resources to device-to-device (D2D) transmissions (101A, 101B and 101C) performed by D2D communication pairs (3A, 3B and 3C) in accordance with an allocation rule that permits two D2D communication pairs (3A and 3C) that are not in proximity to each other to share an identical radio resource but prohibits two D2D communication pairs (3A and 3B) in proximity to each other from sharing an identical radio resource. Each D2D transmission (101) includes wirelessly transmitting from one radio terminal (1) directly to the other radio terminal (1) in each D2D communication pair (3) without passing through the base station (2). It is, thus, possible to enable efficient spatial reuse of radio resources in D2D transmissions performed by D2D communication pairs.

Abstract: A wireless terminal apparatus (2) is configured, before the wireless terminal apparatus (2) is requested by another wireless terminal (1) or a D2D controller (5) to start a relay operation between the other wireless terminal (1) and the cellular network (3, 4), to hold connection information necessary to allow the other wireless terminal (1) to communicate with the cellular network (3, 4) or with a node (7) in an external network (6) via the relay operation performed by the wireless terminal apparatus (2). It is thus, for example, possible to contribute to reducing latency from when a mobile relay is requested to start a relay operation until the relay operation can be started.

Abstract: In one embodiment, a radio terminal (2) is used in a radio communication system (100) and communicates with a radio station (1). The radio terminal (2) includes a measurement unit (20). The measurement unit (20) operates to perform, using a terminal measurement procedure for executing a first terminal measurement corresponding to radio access technology applied to the radio communication system (100), a second terminal measurement of a shared frequency shared by a plurality of radio systems including the radio communication system (100). This embodiment therefore contributes to simplification of a measurement function which should be supported by the radio terminal when the radio communication system uses a shared frequency (e.g., TVWS) shared by the plurality of radio systems.

Abstract: Because it is not possible to sufficiently reduce the number base stations that start uselessly in spite of being in a low traffic state, it is not possible to lower interference between adjacent cells and power consumption sufficiently. A base station starts transmission of a control signal with predetermined power when communication between another base station and a mobile station is started and a first predetermined condition is satisfied.

Abstract: A radio terminal (2) is provided that can be used in a radio communication system (100) and can communicate with a radio station (1). The radio terminal (2) includes a measurement unit (20). The measurement unit (20) operates to perform, using a terminal measurement procedure for executing a first terminal measurement corresponding to radio access technology applied to the radio communication system (100), a second terminal measurement of a shared frequency shared by a plurality of radio systems including the radio communication system (100).

Abstract: Because it is not possible to sufficiently reduce the number base stations that start uselessly in spite of being in a low traffic state, it is not possible to lower interference between adjacent cells and power consumption sufficiently. A base station starts transmission of a control signal with predetermined power when communication between another base station and a mobile station is started and a first predetermined condition is satisfied.

Abstract: A spectrum manager manages a secondary system that shares a frequency with a primary system. A communication unit receives a measurement value of reception power of a signal of the secondary system which is measured by a monitoring station, and holds the measurement value in a measurement result storage unit. A path loss estimating unit estimates a path loss at a first frequency, and a path loss correcting unit performs actual measurement correction on a path loss estimation value using one of a reception power measurement value of a radio signal of a secondary transmitting station measured at a second frequency different from the first frequency and a reception power measurement value of the radio signal of the secondary transmitting station measured in a period of time which is not used by the primary system.

Abstract: In one embodiment, a radio terminal (2) is used in a radio communication system (100) and communicates with a radio station (1). The radio terminal (2) includes a measurement unit (20). The measurement unit (20) operates to perform, using a terminal measurement procedure for executing a first terminal measurement corresponding to radio access technology applied to the radio communication system (100), a second terminal measurement of a shared frequency shared by a plurality of radio systems including the radio communication system (100). This embodiment therefore contributes to simplification of a measurement function which should be supported by the radio terminal when the radio communication system uses a shared frequency (e.g., TVWS) shared by the plurality of radio systems.

Abstract: A radio terminal (2) is used in a radio communication system (100) and communicates with a radio station (1). The radio terminal (2) includes a measurement unit (20). The measurement unit (20) operates to perform, using a terminal measurement procedure for executing a first terminal measurement corresponding to radio access technology applied to the radio communication system (100), a second terminal measurement of a shared frequency shared by a plurality of radio systems including the radio communication system (100).

Abstract: The present invention is a device which, when a second wireless system shares the use of a frequency which is allocated to a first wireless system, estimates receiving power when a second wireless signal which is transmitted from a transmission station of the second wireless system is received at a receiving station of the first wireless system. The receiving power estimation device comprises a correction means for correcting a receiving power estimate value of the second wireless signal at the first wireless system receiving station which is computed using an estimate value of path loss from the second wireless system transmission station to the first wireless system receiving station, said correction using a receiving power measurement value of the second wireless signal which is measured in a transmission station periphery sensor station which is a sensor station which is located in the periphery of the second wireless system transmission station.

Abstract: Because it is not possible to sufficiently reduce the number base stations that start uselessly in spite of being in a low traffic state, it is not possible to lower interference between adjacent cells and power consumption sufficiently. A base station starts transmission of a control signal with predetermined power when communication between another base station and a mobile station is started and a first predetermined condition is satisfied.

Abstract: A frequency management method and device as well as a wireless system are provided by which acceptable transmit power is efficiently determined for transmitting stations in a system on the interfering side, neither with concentration of processing load on some part nor with redundant processing. When a frequency management apparatus (50_1) receives a notice regarding a change in the state of frequency use from a radio station (20_1) under its own management (S101), the frequency management apparatus (50_1) sets acceptable transmit power for radio stations (20_1, 20_2) under its own management and radio stations (20_3, 20_4) managed by another frequency management apparatus (50_2), based on the notified change in the state of frequency (S103, S104).

Abstract: Because it is not possible to sufficiently reduce the number base stations that start uselessly in spite of being in a low traffic state, it is not possible to lower interference between adjacent cells and power consumption sufficiently. A base station starts transmission of a control signal with predetermined power when communication between another base station and a mobile station is started and a first predetermined condition is satisfied.