Avoiding interference in cognitive radio communications

• US 8,909,270 B2
• Filed: 06/23/2010
• Issued: 12/09/2014
• Est. Priority Date: 06/23/2010
• Status: Expired due to Fees

• Current Assignee: RPX Corporation
• Original Assignee: Nokia Corporation
• Inventors: Hottinen, Ari
• Primary Examiner(s): Safaipour, Bobbak
• Application Number:
  US13/703,192
• Publication Number:
  US 20130090141A1
• Time in Patent Office: 1,630 Days
• Field of Search: 455/501
• US Class Current: 455/501
• CPC Class Codes: H04B 15/00 Suppression or limitation of noise or interference by means associated with receiver H04B1/10
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/04 Error control
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 72/542 using measured or perceived quality

Abstract

A method, apparatus, and computer program for cognitive radio communications are provided. A reference signal is received from a transmitter of a primary system, and the received reference signal is received with an arbitrarily selected beamforming setting. Then, a signal quality metric is calculated from the received and beamformed reference signal. If the signal quality metric indicates that a reception power of the received signal is low, transmission of a data signal to a wireless communication device of a secondary system is scheduled. In the scheduled transmission in the secondary system, the same beamforming setting as was used in the reception of the reference signal is employed.

Claims

1. A method, comprising:

receiving, in a wireless communication apparatus, a reference signal from a transmitter of a primary system through a radio channel in a radio communication resource;

applying an arbitrarily selected reception beamforming setting to the received signal, wherein the arbitrarily selected beamforming setting is selected arbitrarily from a set comprising at least two beamforming settings;

estimating a signal quality metric from the received signal to which the selected reception beamforming setting has been applied;

scheduling transmission of a data signal in said radio communication resource to a wireless communication device of a secondary system with a transmission beamforming setting having the same beamforming parameters as the reception beamforming setting, wherein the scheduling is triggered when the estimated signal quality metric indicates a signal quality lower than a determined threshold.

2. The method of claim 1, wherein said reception beamforming setting is selected without information on channel conditions between the wireless communication apparatus and the transmitter of the primary system.

3. The method of claim 1, further comprising:

changing the arbitrary reception beamforming setting between time slots in which signals from the transmitter of the primary system are received.

4. The method of claim 1, wherein a set of arbitrary reception beamforming settings is repeated in a cyclic manner.

5. The method of claim 1, wherein the signal quality metric estimated from the signal received from the transmitter of the primary system is a first signal quality metric and wherein said threshold is a first threshold, the method further comprising:

receiving a second signal from the wireless communication device of the secondary system;

estimating a second signal quality metric from said second signal; and

scheduling the transmission of the signal to the wireless communication device of the secondary system if the first signal quality metric indicates a signal quality lower than the first threshold and if the second signal quality metric indicates a signal quality higher than a determined second threshold.

6. The method of claim 1, wherein the signal quality metric estimated from the signal received from the transmitter of the primary system is a first signal quality metric, the method further comprising:

receiving a second signal from the wireless communication device of the secondary system;

estimating a second signal quality metric from said second signal;

combining the first signal quality metric and the second signal quality metric into a single signal quality metric;

comparing the combined signal quality metric with said threshold; and

scheduling the transmission of the signal to the wireless communication device of the secondary system if the combined signal quality metric is in a determined range with respect to the threshold.

7. The method of claim 1, wherein said signal quality metrics are estimated reception signal power values, and wherein the reception signal power estimated from the signal received from the transmitter of the primary system is considered to be proportional to interference the wireless communication apparatus causes towards the transmitter of the primary system.

8. The method of claim 1, further comprising:

adjusting transmission power of the scheduled transmission to the wireless communication device of the secondary system in proportion to the signal quality metric estimated from the signal received from the transmitter of the primary system.

9. The method of claim 1, wherein the arbitrary selection of the beamforming setting comprises selecting from a codebook of beamforming settings sequentially or randomly a beamforming setting to be applied to the received signal.

10. An apparatus comprising:

at least one processor; and

at least one memory including a computer program code, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to receive a reference signal from a transmitter of a primary system through a radio channel, wherein the signal is associated to a radio communication resource, to apply an arbitrarily selected reception beamforming setting to the received signal, wherein the arbitrarily selected beamforming setting is selected arbitrarily from a set comprising at least two beamforming settings, to estimate a signal quality metric from the received signal to which the arbitrarily selected reception beamforming setting has been applied, and to schedule transmission of a data signal in said radio communication resource to a wireless communication device of a secondary system with a transmission beamforming setting having the same beamforming parameters as the reception beamforming setting, wherein the scheduling is triggered when the estimated signal quality metric indicates a signal quality lower than a determined threshold.

11. The apparatus of claim 10, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to select the reception beamforming setting without information on channel conditions between the wireless communication apparatus and the transmitter of the primary system.

12. The apparatus of claim 10, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to change the arbitrary reception beamforming setting between time slots in which signals from the transmitter of the primary system are received.

13. The apparatus of claim 10, wherein a set of arbitrary reception beamforming settings is repeated in a cyclic manner.

14. The apparatus of claim 10, wherein the signal quality metric estimated from the signal received from the transmitter of the primary system is a first signal quality metric, wherein said threshold is a first threshold, and wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to receive a second signal from the wireless communication device of the secondary system, to estimate a second signal quality metric from said second signal, and to schedule the transmission of the signal to the wireless communication device of the secondary system if the first signal quality metric indicates a signal quality lower than the first threshold and if the second signal quality metric indicates a signal quality higher than a determined second threshold.

15. The apparatus of claim 10, wherein the signal quality metric estimated from the signal received from the transmitter of the primary system is a first signal quality metric, and wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to receive a second signal from the wireless communication device of the secondary system, to estimate a second signal quality metric from said second signal, to combine the first signal quality metric and the second signal quality metric into a single signal quality metric, to compare the combined signal quality metric with said threshold, and to schedule the transmission of the signal to the wireless communication device of the secondary system if the combined signal quality metric is in a determined range with respect to the threshold.

16. The apparatus of claim 10, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to estimate said signal quality metrics as reception signal power values, and to consider the reception signal power estimated from the signal received from the transmitter of the primary system to be proportional to interference the apparatus causes towards the transmitter of the primary system with said beamforming setting.

17. The apparatus of claim 10, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to adjust transmission power of the scheduled transmission to the wireless communication device of the secondary system in proportion to the signal quality metric estimated from the signal received from the transmitter of the primary system.

18. The apparatus of claim 10, wherein the apparatus is a wireless communication device and further comprises a user interface for outputting data received through the radio channel from at least one of the transmitter of the primary system and the wireless communication device of the secondary system.

19. The apparatus of claim 10, wherein the at least one memory and the computer program code are configured, with the at least one processor, to cause the apparatus to carry out the arbitrary selection of the beamforming setting by selecting from a codebook of beamforming settings sequentially or randomly a beamforming setting to be applied to the received signal.

20. A computer program product embodied on a non-transitory distribution medium readable by a computer and comprising program instructions which, when loaded into an apparatus, execute a computer process comprising:

receiving a reference signal from a transmitter of a primary system through a radio channel in a radio communication resource;

applying an arbitrarily selected reception beamforming setting to the received signal, wherein the arbitrarily selected beamforming setting is selected arbitrarily from a set comprising at least two beamforming settings;

estimating a signal quality metric from the received signal to which the selected reception beamforming setting has been applied;

scheduling transmission of a data signal in said radio communication resource to a wireless communication device of a secondary system with a transmission beamforming setting having the same beamforming parameters as the reception beamforming setting, wherein the scheduling is triggered when the estimated signal quality metric indicates a signal quality lower than a determined threshold.