Mobile communication system, communication control method, base station, user terminal and processor
A mobile communication system comprises: a user terminal that receives a desired wave signal from a serving cell and an interference wave signal that is a signal to another user terminal; and a first base station that manages the serving cell. The first base station includes: a control unit configured to generate configured to an interference replica signal corresponding to the interference wave signal and to superpose the interference replica signal on the desired wave signal; and a transmission unit configured to transmit the desired wave signal superposed with the interference replica signal to the user terminal. The control unit generates the interference replica signal such that the interference replica signal received by the user terminal cancels the interference wave signal received by the user terminal.
1. A mobile communication system comprising:
a user terminal that receives a desired wave signal from a serving cell and an interference wave signal that is a signal to another user terminal;
a first base station that manages the serving cell;
a second base station that manages a neighbor cell adjacent to the serving cell; and
a management device that manages the first base station and the second base station, wherein
the first base station includes:
a controller that generates an interference replica signal corresponding to the interference wave signal and superposes the interference replica signal on the desired wave signal;
a transmitter that transmits the desired wave signal superposed with the interference replica signal to the user terminal; and
a receiver that receives information used for generating the interference replica signal from at least one of the second base station, the management device, and the user terminal, wherein
the controller generates the interference replica signal such that the interference replica signal received by the user terminal cancels the interference wave signal received by the user terminal,
the controller generates the interference replica signal on the basis of the information received by the receiver,
the information used for generating the interference replica signal includes waveform information relating to a signal waveform of the interference wave signal,
the second base station transmits the waveform information to the first base station, and
the receiver receives the waveform information.
2. The mobile communication system according to claim 1 , wherein
the another user terminal is connected to the neighbor cell, and
the interference wave signal is a signal from the neighbor cell.
3. The mobile communication system according to claim 1 , wherein
the controller generates the interference replica signal such that a phase of the interference replica signal received by the user terminal is opposite to a phase of the interference wave signal received by the user terminal.
4. The mobile communication system according to claim 1 , wherein
the controller generates the interference replica signal such that an amplitude of the interference replica signal received by the user terminal is equal to an amplitude of the interference wave signal received by the user terminal.
5. The mobile communication system according to claim 1 , wherein
the first base station includes at least one antenna associated with the serving cell, and
the controller determines whether or not to apply superposition transmission in which the interference replica signal is superposed on the desired wave signal, on the basis of a number of the at least one antenna.
6. The mobile communication system according to claim 1 , wherein
the controller determines whether or not to apply superposition transmission in which the interference replica signal is superposed on the desired wave signal, on the basis of a received signal state in the user terminal.
7. The mobile communication system according to claim 1 , wherein
the controller determines whether or not to apply superposition transmission in which the interference replica signal is superposed on the desired wave signal, on the basis of a usage status of a radio resource in the mobile communication system.
8. The mobile communication system according to claim 1 , wherein
the controller determines whether or not to apply superposition transmission in which the interference replica signal is superposed on the desired wave signal, on the basis of Quality of Service (QoS) required by the user terminal.
9. The mobile communication system according to claim 1 , wherein the controller transmits resource information indicating a radio resource used for transmitting the desired wave signal, to the second base station, and
the second base station transmits the waveform information to the first base station, on the basis of the resource information.
10. The mobile communication system according to claim 1 , wherein
the information used for generating the interference replica signal includes transmission data obtained before being converted into the interference wave signal in the second base station,
the second base station transmits the transmission data to the first base station, and
the receiver receives the transmission data from the second base station.
11. The mobile communication system according to claim 10 , wherein
the information used for generating the interference replica signal further includes transmission process information indicating a content of a transmission process used when the transmission data is converted into the interference wave signal in the second base station,
the second base station further transmits the transmission process information to the first base station, and
the receiver further receives the transmission process information from the second base station.
12. The mobile communication system according to claim 1 , wherein
the information used for generating the interference replica signal includes transmission data obtained before being converted into the interference wave signal in the second base station,
the management device transmits the transmission data to the first base station, and
the receiver receives the transmission data from the management device.
13. The mobile communication system according to claim 12 , wherein
the information used for generating the interference replica signal further includes transmission process information indicating a content of a transmission process used when the transmission data is converted into the interference wave signal in the second base station,
the second base station transmits the transmission process information to the first base station, and
the receiver receives the transmission process information from the second base station.
14. The mobile communication system according to claim 1 , wherein
the interference wave signal includes a data signal transmitted on a physical downlink shared channel,
the information used for generating the interference replica signal is difference information indicating at least one of an amplitude difference and a phase difference between the data signal and a reference signal transmitted by the second base station,
the second base station transmits the difference information to the first base station, and
the receiver receives the difference information from the second base station.
15. The mobile communication system according to claim 1 , wherein
the information used for generating the interference replica signal is received power information indicating received power about a reference signal received by the user terminal from the second base station,
the user terminal transmits the received power information to the second base station,
the second base station transfers the received power information to the first base station, and
the receiver receives the received power information from the second base station.
16. The mobile communication system according to claim 1 , wherein
the information used for generating the interference replica signal is received power information indicating received power about a reference signal received by the user terminal from the second base station,
the user terminal transmits the received power information to the first base station, and
the receiver receives the received power information from the user terminal.
17. The mobile communication system according to claim 1 , wherein
the interference wave signal includes a data signal transmitted on a physical downlink shared channel,
the information used for generating the interference replica signal is power difference information indicating a power difference between the data signal and a reference signal transmitted by the second base station,
the user terminal transmits the power difference information to the first base station, and
the receiver receives the power difference information from the user terminal.
18. The mobile communication system according to claim 1 , wherein
the interference wave signal includes a data signal transmitted on a physical downlink shared channel,
the information used for generating the interference replica signal is power difference information indicating a power difference between the data signal and a reference signal transmitted by the second base station,
the second base station transmits the power difference information to the first base station, and
the receiver receives the power difference information from the second base station.
19. The mobile communication system according to claim 1 , wherein
the information used for generating the interference replica signal is time difference information indicating a delay time difference between a delay time from the first base station to the user terminal and a delay time from the second base station to the user terminal,
the user terminal transmits the time difference information to the first base station, and
the receiver receives the time difference information from the user terminal.
20. The mobile communication system according to claim 1 , wherein
the information used for generating the interference replica signal is channel information indicating a channel characteristic between the second base station and the user terminal,
the receiver receives the channel information from at least one of the second base station and the user terminal, and
the controller generates the interference replica signal on the basis of the channel information received by the receiver.
21. The mobile communication system according to claim 20 , wherein
the user terminal generates the channel information on the basis of a reference signal received from the second base station and transmits the generated channel information to the first base station, and
the receiver receives the channel information from the user terminal.
22. The mobile communication system according to claim 20 , wherein
the user terminal generates the channel information on the basis of a reference signal received from the second base station and transmits the generated channel information to the second base station,
the second base station transfers, to the first base station, the channel information from the user terminal, and
the receiver receives the channel information from the second base station.
23. The mobile communication system according to claim 21 , wherein
the first base station transmits, to the user terminal, cell designation information indicating a cell for which a channel characteristic should be estimated, and
the user terminal estimates the channel characteristic about the cell indicated by the cell designation information to thereby generate the channel information.
24. The mobile communication system according to claim 20 , wherein
the second base station generates the channel information on the basis of a reference signal received from the user terminal and transmits the generated channel information to the first base station, and
the receiver receives the channel information from the second base station.
25. The mobile communication system according to claim 24 , wherein
the first base station transmits, to the second base station, terminal designation information indicating a user terminal for which a channel characteristic should be estimated, and
the second base station estimates the channel characteristic about the user terminal indicated by the terminal designation information to thereby generate the channel information.
26. The mobile communication system according to claim 24 , wherein
the first base station transmits, to the second base station, demodulation-use information for demodulating the reference signal transmitted by the user terminal, and
the second base station demodulates the reference signal by using the demodulation-use information to thereby generate the channel information.
27. A communication control method used in a mobile communication system comprising a user terminal that receives a desired wave signal from a serving cell and an interference wave signal that is a signal to another user terminal and a first base station that manages the serving cell; a second base station that manages a neighbor cell to which the another user terminal is connected and which is adjacent to the serving cell; and a management device that manages the first base station and the second base station, the communication control method comprising the steps of:
by the first base station,
receiving information used for generating the interference replica signal from at least one of the second base station, the management device, and the user terminal;
generating, on the basis of the information received, an interference replica signal corresponding to the interference wave signal;
superposing the interference replica signal on the desired wave signal; and
transmitting the desired wave signal superposed with the interference replica signal to the user terminal, wherein
the interference replica signal is generated such that the interference replica signal received by the user terminal cancels the interference wave signal received by the user terminal.
28. The communication control method according to claim 27 , wherein
the information used for generating the interference replica signal is channel information indicating a channel characteristic between the second base station and the user terminal.
29. A base station, which manages a serving cell in a mobile communication system including a user terminal that receives a desired wave signal from the serving cell and an interference wave signal that is a signal to another user terminal, comprising:
a controller that generates an interference replica signal corresponding to the interference wave signal and to superpose the interference replica signal on the desired wave signal;
a transmitter that transmits, to the user terminal, the desired wave signal superposed with the interference replica signal; and
a receiver that receives information used for generating the interference replica signal from at least one of another base station that manages a neighbor cell to which the another user terminal is connected and which is adjacent to the serving cell, a management device that manages the base station and the another base station, and the user terminal, wherein
the controller generates the interference replica signal such that the interference replica signal received by the user terminal cancels the interference wave signal received by the user terminal, and
the controller generates the interference replica signal on the basis of the information received by the receiver.
30. The base station according to claim 29 , wherein
the information used for generating the interference replica signal is channel information indicating a channel characteristic between the another base station and the user terminal.
31. A base station, which manages a neighbor cell in a mobile communication system including a user terminal that receives a desired wave signal from a serving cell and an interference wave signal from the neighbor cell adjacent to the serving cell, wherein:
another base station that manages the serving cell transmits an interference replica signal corresponding to the interference wave signal by superposing the interference replica signal on the desired wave signal,
the base station includes a transmitter communicatively coupled to a memory, the transmitter transmitting to the another base station, information used for generating the interference replica signal,
the information used for generating the interference replica signal includes waveform information relating to a signal waveform of the interference wave signal, and
the interference replica signal is generated by the another base station such that the interference replica signal received by the user terminal cancels the interference wave signal received by the user terminal.
32. The base station according to claim 31 , wherein the information used for generating the interference replica signal is channel information indicating a channel characteristic between the base station and the user terminal.
33. A user terminal that receives a desired wave signal from a serving cell and an interference wave signal that is a signal to another user terminal,
the user terminal comprising:
a transmitter communicatively coupled to a memory, the transmitter transmitting, to a first base station that manages the serving cell, information used for generating an interference replica signal, wherein
the information used for generating the interference replica signal is received power information indicating received power about a reference signal received by the user terminal from a second base station, and
the first base station transmits the interference replica signal corresponding to the interference wave signal by superposing the interference replica signal on the desired wave signal.
34. The user terminal according to claim 33 , wherein
the information used for generating the interference replica signal is channel information indicating a channel characteristic between the user terminal and a second base station that manages a neighbor cell to which the another user terminal is connected and which is adjacent to the serving cell.
35. A processor communicatively coupled to a memory and provided in a base station that manages a serving cell in a mobile communication system including a user terminal that receives a desired wave signal from the serving cell and an interference wave signal that is a signal to another user terminal, wherein the processor executes:
a generation process of generating an interference replica signal corresponding to the interference wave signal;
a superposition process of superposing the interference replica signal on the desired wave signal;
a transmission process of transmitting the desired wave signal superposed with the interference replica signal to the user terminal; and
a reception process of receiving information used for generating the interference replica signal from at least one of another base station that manages the neighbor cell to which the another user terminal is connected and which is adjacent to the serving cell, a management device that manages the base station and the another base station, and the user terminal, wherein
in the generation process, the interference replica signal is generated on the basis of the received information, and
in the generation process, the interference replica signal is generated such that the interference replica signal received by the user terminal cancels the interference wave signal received by the user terminal.
36. The processor according to claim 35 , wherein the processor further executes:
a reception process of receiving information used for generating the interference replica signal from at least one of another base station that manages the neighbor cell to which the another user terminal is connected and which is adjacent to the serving cell, a management device that manages the base station and the another base station, and the user terminal, wherein
in the generation process, the interference replica signal is generated on the basis of the received information.
37. The processor according to claim 36 , wherein
the information used for generating the interference replica signal is channel information indicating a channel characteristic between the another base station and the user terminal.
38. A processor communicatively coupled to a memory and provided in a base station that manages a neighbor cell in a mobile communication system including a user terminal that receives a desired wave signal from a serving cell and an interference wave signal from the neighbor cell adjacent to the serving cell, wherein:
another base station that manages the serving cell transmits an interference replica signal corresponding to the interference wave signal by superposing the interference replica signal on the desired wave signal,
the processor performs a process of transmitting, to the another base station, the information used for generating the interference replica signal,
the information used for generating the interference replica signal includes waveform information relating to a signal waveform of the interference wave signal, and
the interference replica signal is generated by the another base station such that the interference replica signal received by the user terminal cancels the interference wave signal received by the user terminal.
39. The processor according to claim 38 , wherein
the information used for generating the interference replica signal is channel information indicating a channel characteristic between the base station and the user terminal.
40. A processor communicatively coupled to a memory and provided in a user terminal that receives a desired wave signal from a serving cell and an interference wave signal that is a signal to another user terminal, wherein:
a first base station that manages the serving cell transmits an interference replica signal corresponding to the interference wave signal by superposing the interference replica signal on the desired wave signal,
the processor performs a process of transmitting, to the first base station, the information used for generating the interference replica signal, and
the information used for generating the interference replica signal is received power information indicating received powers about a reference signal received by the user terminal from a second base station.
41. The processor according to claim 40 , wherein
the information used for generating the interference replica signal is channel information indicating a channel characteristic between the user terminal and a second base station that manages a neighbor cell to which the another user terminal is connected and which is adjacent to the serving cell.