COGNITIVE RADIO COMMUNICATION SYSTEM USING MULTIPLE INPUT MULTIPLE OUTPUT COMMUNICATION SCHEME

• US 20090304110A1
• Filed: 03/09/2009
• Published: 12/10/2009
• Est. Priority Date: 06/10/2008
• Status: Active Grant

• Current Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Original Assignee: Korea Advanced Institute of Science and Technology, Samsung Electronics Co. Ltd.
• Inventors: Choi, Hyun Ho, Cho, Dong Ho, Jo, Ohyun, Lee, Ki Song, Lee, Woongsup
• Granted Patent: US 8,982,996 B2
• Time in Patent Office: Days
• US Class Current: 375/299
• CPC Class Codes: H04L 27/00 Modulated-carrier systems

Abstract

A cognitive radio communication system using a multiple input multiple output (MIMO) communication technology is provided. A cognitive radio base station includes a plurality of antennas, a group setting unit to set at least one sensing terminal group that includes at least one sensing terminal among a plurality of terminals, and a signal generator to generate a transmission signal to transmit the transmission signal using channels formed between the plurality antennas and the plurality of terminals, so that the at least one sensing terminal is accorded a sensing time.

Claims

1. A cognitive radio base station comprising:

a plurality of antennas;

a group setting unit to set at least one sensing terminal group that includes at least one sensing terminal among a plurality of terminals; and

a signal generator to generate a transmission signal to transmit the transmission signal using channels formed between the plurality antennas and the plurality of terminals, so that the at least one sensing terminal is accorded a sensing time.

2. The cognitive radio base station of claim 1, wherein the signal generator generates the transmission signal so that a signal received by the at least one sensing terminal is null or near-null.

3. The cognitive radio base station of claim 2, wherein the plurality of antennas simultaneously transmits the transmission signal for the at least one sensing terminal and at least one remaining terminal excluding the at least one sensing terminal.

4. The cognitive radio base station of claim 1, wherein, where the at least one sensing terminal group includes a plurality of subsets, the signal generator generates the transmission signal so that a signal received by the at least one sensing terminal belonging to the plurality of subsets is null or near-null.

5. The cognitive radio base station of claim 1, wherein the group setting unit recognizes the existence of a primary user and sets the at least one sensing terminal group that includes the at least one sensing terminal, based on a location of the primary user.

6. The cognitive radio base station of claim 1, wherein the group setting unit sets the at least one sensing terminal group that includes the at least one sensing terminal based on a distance between a primary user and the plurality of terminals.

7. The cognitive radio base station of claim 1, wherein the at least one sensing terminal belonging to the at least one sensing terminal group senses a signal of a primary user while receiving the transmission signal.

8. The cognitive radio base station of claim 4, wherein the at least one sensing terminal belonging to the plurality of subsets senses a signal of a primary user.

9. The cognitive radio base station of claim 1, further comprising:

a band controller to adaptively control a downlink band and an uplink band so that a usage frequency band of a primary user may be included in the downlink band, in a cognitive radio communication system that adopts a frequency division duplex scheme separately using the downlink band and the uplink band,

wherein the at least one sensing terminal belonging to the at least one sensing terminal group senses a signal of the primary user using the controlled downlink band while receiving the transmission signal.

10. The cognitive radio base station of claim 9, wherein the at least one sensing terminal reports a sensing result regarding the signal of the primary user using the controlled uplink band.

11. The cognitive radio base station of claim 5, wherein:

at least one terminal among the plurality of terminals recognizes the existence of the primary user according to a fast sensing scheme, and

the group setting unit receives information associated with the existence of the recognized primary user from the at least one terminal among the plurality of terminals.

12. A cognitive ratio base station comprising:

a group setting unit to set at least one sensing terminal group that includes at least one sensing terminal to perform a fine sensing among a plurality of terminals; and

an uplink communication terminal decision unit to determine at least one uplink communication terminal to perform an uplink communication among the plurality of terminals, so that the at least one sensing terminal is accorded a sensing time in an uplink time interval.

13. The cognitive radio base station of claim 12, wherein the uplink communication terminal decision unit determines the at least one uplink communication terminal based on at least one of a transmission power of the terminals, a location of the at least one sensing terminal, locations of the terminals, and a tolerable threshold of interference occurring in the at least one sensing terminal due to the plurality of terminals.

14. The cognitive radio base station of claim 12, wherein the uplink communication terminal decision unit determines the at least one uplink communication terminal based on interference occurring in the at least one sensing terminal due to the at least one uplink communication terminal.

15. The cognitive radio base station of claim 12, wherein the group setting unit sets the at least one sensing terminal group based on a distance between a primary user and the plurality of terminals.

16. The cognitive radio base station of claim 15, wherein:

at least one terminal among the plurality of terminals recognizes the existence of the primary user according to a fast sensing scheme, and

the group setting unit sets the at least one sensing terminal group based on information associated with the existence of the primary user.

17. The cognitive radio base station of claim 12, further comprising:

an information provider to provide the plurality of terminals with information associated with the determined at least one uplink communication terminal.

18. The cognitive radio base station of claim 16, wherein the remaining terminals excluding the determined at least one uplink communication terminal among the plurality of terminals do not perform the uplink communication in the uplink time interval, based on information associated with the determined at least one uplink communication terminal.

19. A method of operating a sensing terminal among a plurality of cognitive radio terminals, the method comprising:

recognizing by the sensing terminal the existence of a primary user according to a fast sensing scheme to report to a cognitive radio base station information associated with the existence of the primary user; and

sensing by the sensing terminal a signal of the primary user while the cognitive radio base station transmits a transmission signal,

wherein the cognitive radio base station transmits the transmission signal via a plurality of antennas, so that the sensing terminal is accorded a sensing time.

20. The method of claim 19, wherein the cognitive radio base station transmits the transmission signal, so that a signal received by the sensing terminal is null or near-null, and at least one remaining terminal excluding the sensing terminal among the plurality of cognitive radio terminals receives data.

21. The method of claim 19, wherein the sensing comprises sensing the signal of the primary user according to a fine sensing scheme.

22. A method of operating a cognitive radio base station, the method comprising:

setting by the cognitive radio base station at least one sensing terminal group that includes at least one sensing terminal among a plurality of terminals;

generating by the cognitive radio base station a transmission signal to transmit the transmission signal using channels formed between a plurality of antennas and the plurality of terminals, so that the at least one sensing terminal is accorded a sensing time; and

transmitting by the cognitive radio base station the transmission signal to the plurality of terminals via the plurality of antennas.

23. The method of claim 22, wherein:

the generating comprises generating the transmission signal so that a signal received by the at least one sensing terminal is null or near-null and at least one remaining terminal excluding the at least one sensing terminal receives data, and

the transmitting comprises transmitting the transmission signal to the at least one sensing terminal and the at least one remaining terminal.

24. The method of claim 22, wherein the at least one sensing terminal senses a signal of a primary user while receiving the transmission signal.

25. A method of operating a cognitive radio base station, the method comprising:

setting by the cognitive radio base station at least one sensing terminal group that includes at least one sensing terminal to perform a fine sensing among a plurality of terminals; and

determining by the cognitive radio base station at least one uplink communication terminal to perform an uplink communication among the plurality of terminals, so that the at least one sensing terminal is accorded a sensing time in an uplink time interval.

26. The method of claim 25, wherein the determining comprises determining the at least one uplink communication terminal based on at least one of a transmission power of the terminals, a location of the at least one sensing terminal, locations of the terminals, and a tolerable threshold of interference occurring in the at least one sensing terminal due to the plurality of terminals.

27. A computer-readable storage medium storing a program to operate a sensing terminal of a cognitive radio communication system, comprising instructions to cause the sensing terminal to:

recognize the existence of a primary user according to a fast sensing scheme to report to a cognitive radio base station information associated with the existence of the primary user; and

sense a signal of the primary user while the cognitive radio base station transmits a transmission signal,

wherein the cognitive radio base station transmits the transmission signal via a plurality of antennas, so that the sensing terminal is accorded a sensing time.