METHOD FOR DATABASE DRIVEN CHANNEL QUALITY ESTIMATION IN A COGNITIVE RADIO NETWORK

• US 20100330919A1
• Filed: 06/29/2009
• Published: 12/30/2010
• Est. Priority Date: 06/29/2009
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: KUFFNER, STEPHEN L., GURNEY, DAVID P.
• Granted Patent: US 8,660,498 B2
• Time in Patent Office: Days
• US Class Current: 455/67.11
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 52/228 using past power values or information
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/281 taking into account user or data type priority
• CPC Class Codes: H04W 52/283 Power depending on the position of the mobile
• CPC Class Codes: H04W 52/367 Power values between minimum and maximum limits, e.g. dynamic range
• CPC Class Codes: H04W 72/541 using the level of interference
• CPC Class Codes: H04W 72/56 based on priority criteria

Abstract

A method of determining operating parameters for a secondary system transmitter is described. The transmitter characteristics, including location and operating frequency band, are provided to a geo-location database. The database determines the maximum allowable transmission power that meets various specifications for different channels and conveys the power and channel(s) to the transmitter. The database estimates channel incumbent signal strengths based on the transmitter location and primary and higher-priority secondary incumbent systems, estimates the splatter levels, determines whether adjacent and co-channel interference protection ratios are met, and adjusts the allowable power level accordingly. The database also estimates aggregate co- and adjacent channel primary and secondary incumbent system interference levels at the transmitter location and predicts channel quality for each allowable channel. The estimated levels are updated using measurements of actual levels at the transmitter location. The database dynamically allocates channels using the secondary system priorities.

Claims

1. A method of deriving channel quality information for a secondary device operating in a spectrum of a primary system, the method comprising:

gathering operating parameters of the primary system and the secondary device;

computing, based on the operating parameters, a maximum allowed transmission power level for a specified operating frequency at a specified operating location of the secondary device;

estimating an aggregate interference level for the specified operating frequency and location;

estimating a channel quality of the specified operating frequency and location based on the maximum allowed transmission power level and the aggregate interference level.

2. The method of claim 1, further comprising selecting an operational frequency that has the highest estimated channel quality for the secondary device.

3. The method of claim 1, wherein the maximum allowed transmission power level is computed based on allowable harmful interference levels to the primary system.

4. The method of claim 1, wherein the estimated channel quality of the specified channel is related to a difference between the maximum allowed transmission power level and the aggregate interference level.

5. The method of claim 1, wherein the aggregate interference level is estimated based on at least one of on-channel emissions or off-channel emissions of the primary system.

6. The method of claim 1, wherein the aggregate interference level is estimated based on at least one of on-channel emissions or off-channel emissions of other secondary devices operating in the spectrum of the primary system.

7. The method of claim 1, wherein at least some of the operational parameters are gathered from a regulatory database.

8. The method of claim 1, wherein at least some of the operational parameters are reported to a central database.

9. A method of determining operating parameters for secondary system usage in a network containing a geo-location database, a primary incumbent system and secondary devices, the database containing information of the primary incumbent system and secondary devices including locations of transmitters and receivers of the primary incumbent system and locations of the secondary devices, the method comprising:

determining a location of a secondary transmitter;

providing to the database transmitter information including the location of the secondary transmitter and a frequency band of operation of the secondary transmitter;

the database;

determining an allowable maximum transmission power of the secondary transmitter for a channel in the frequency band of operation to meet interference tolerance specifications at the location of at least one of the primary receivers;

indicating the allowable maximum transmission power level and an allowable transmission channel in the frequency band of operation to the secondary transmitter;

estimating an aggregate interference level at the location of a secondary receiver based on on-channel and off-channel emissions of the primary and secondary transmitters; and

estimating a channel quality of the channel at the location of the secondary receiver based on the allowable maximum transmission power level and the estimated aggregate interference level.

10. The method of claim 9, wherein the secondary transmitter transmits on a transmission channel that has the highest estimated channel quality.

11. The method of claim 9, wherein a transmission channel on which the secondary transmitter transmits is determined by the database.

12. The method of claim 9, further comprising periodically providing operating characteristics of the secondary transmitter to the database after selection by the transmitter of a transmission channel on which the secondary transmitter transmits.

13. The method of claim 9, wherein a transmission channel on which the secondary transmitter transmits is contained within a list of permissible transmission channels indicated to the secondary transmitter, each of the channels in the list of permissible transmission channels is in the frequency band and meets specifications for the frequency band set by a governing body, and the permissible transmission channels list further includes channels other than open channels, the method further comprising the secondary transmitter selecting the transmission channel from the list of permissible transmission channels.

14. The method of claim 9, wherein:

determination of the allowable maximum transmission power comprises the database;

estimating channel incumbent signal strengths based on the location of the at least one of the primary receivers;

determining whether adjacent and co-channel interference protection ratios for the at least one of the receivers are met by the secondary transmitter operating at an initial maximum transmission power level, the adjacent channel interference protection ratios at least meeting adjacent and co-channel interference specifications for the at least one of the receivers as set by a governing body;

if the adjacent and co-channel interference protection ratios are not met by the secondary transmitter operating at the initial maximum transmission power level, reducing the allowable maximum transmission power level of the secondary transmitter from the initial maximum transmission power level until the adjacent and co-channel interference protection ratios are met.

15. The method of claim 9, wherein the aggregate interference level comprises interference contributions from co- and adjacent channel primary and secondary transmitters.

16. The method of claim 15, further comprising:

measuring actual interference levels at the location of the secondary transmitter caused by the primary and secondary transmitters; and

updating estimations of the interference contributions in the database based on the measured interference levels.

17. The method of claim 9, wherein the network contains a plurality of at least one of primary or secondary incumbent systems, the database determining the allowable maximum transmission power to meet interference tolerance specifications for all primary incumbent systems as well as any secondary incumbent systems of higher priority than the secondary system containing the secondary transmitter.

18. The method of claim 17, further comprising the database determining priorities of all secondary systems in the network, the priorities of the secondary systems being based on at least one of function or seniority.

19. The method of claim 17, further comprising the database dynamically allocating channels for transmission by the secondary transmitter using priorities of the secondary systems such that the secondary transmitter is reallocated to a different channel if the database determines that a transmitter of a secondary system having a higher priority is to use a channel currently allocated to the transmitter for transmission.

20. The method of claim 9, further comprising the secondary transmitter periodically determining whether its location has changed and, if so, sending the changed location to the database for determination by the database as to whether to adjust the allowable maximum transmission power level.