METHOD AND A SYSTEM FOR CONTROLLING THE AGGREGATE INTERFERENCE IN COGNITIVE RADIO NETWORKS

• US 20130336155A1
• Filed: 02/24/2012
• Published: 12/19/2013
• Est. Priority Date: 02/24/2011
• Status: Active Grant

• Current Assignee: Raniot Technologies Oy (Skylo Technologies Inc.)
• Original Assignee: Riku Jantti
• Inventors: Jntti, Riku, Ruttik, Kalle, Koufos, Konstantinos
• Granted Patent: US 9,088,910 B2
• Time in Patent Office: Days
• US Class Current: 370/252
• CPC Class Codes: H04W 16/14 Spectrum sharing arrangements between different networks
• CPC Class Codes: H04W 24/08 Testing, supervising or monitoring using real traffic
• CPC Class Codes: H04W 52/244 Interferences in heterogeneous networks, e.g. among macro and femto or pico cells or other sector / system interference [OSI]

Abstract

A method for controlling the aggregate interference of a secondary system (10) in a cognitive radio network comprises the steps of computing the power density (Pd,i), footprint (Afoot,i) and service area (Ai) for each of the cells (100) of the secondary system (10) that satisfy the interference constraint at a given point (P) in a primary system (50); summing the power densities (Pd,i) for all cells (100) for the point (P); and using the sum of the power density at the point (P) to decide which power level a new secondary system (10) user is allowed to use in a given cell (100). A system for performing such a method is also disclosed.

Claims

configured. configured to allocate to the secondary system (10) a sub-fraction of the interference margin (I_Δ

,p) contained in a given data-base (150), most advantageously for each primary system (50) test point (P).

1. A computerized method for computing the aggregate interference of a secondary system (10) in a radio network and for displaying the results of said computation to a user in order to allow for controlling the aggregate interference of said secondary system, the method comprising the steps of:

computing, by a pre-programmed computational device, a power density (P_d,i), a footprint (A_foot,i) and a service area (A_i) for each of a plurality of cells (100) of the secondary system (10) that satisfy an interference constraint at a given point (P) in a primary system (50), said computing performed in such a manner that;

said power density (P_d,i) is computed as a secondary transmitter density (ρ

_i) for each of said plurality of cells (100) multiplied with a secondary user power (P_SU,i) of each corresponding respective cell (100); and

said footprint (A_foot,i) is computed as an inverse of the secondary transmitter density (ρ

_i) for each of said plurality of cells (100);

responsive to computing said power density (P_d,i) for each of said plurality of cells (100), said computational device summing the power densities (P_d,i) for all said plurality of cells (100) for the point (P) weighted by an aggregated link gain (∫

_Aig_a^mda) of secondary user (SU) coverage areas (A_i) and shadow fading (E{x^m}) ; and

using the sum of the power density at the point (P)- to compute an aggregate interference in order to display which power level a new secondary system (10) is allowed to use in a given cell (100).

2. The method according to claim 1, wherein the computing by the computational device is performed locally in the given cell (100).

3. The method according to claim 1, wherein the computed power density (P_d,i), footprint (A_foot,i) and service area (A_i) for each of the cells (100) are stored in a database (150) by said computational device.

4. The method according to claim 3, wherein the database (150) is a cell (100) specific database that is stored in a cell (100).

5. The method according to claim 3, wherein the computed power density (P_d,i), footprint (A_foot,i) and service area (A_i) are distributed between a plurality of databases (150).

6. The method according to claim 1, wherein:

an interference margin is computed as an amount of additional interference (I<sub>Δ

,p</sub>) that can be added at each test point (301, P) or at each primary system (DTT, 50) test point (P); and

wherein said computational device allocates a fraction of the computed interference margin to a secondary transmitter and/or to a secondary system.

7. The method according to claim 6, wherein the allocated fraction is computed as the interference margin (I_Δ

,p) that the secondary system (10) should satisfy at each primary system (50) test point (P).

8. The method according to claim 6, wherein the allocated fraction is computed as a power density (P_d,i) that the secondary system (10) can use in its service area (A_i) .

9. The method according to claim 7, wherein the aggregate interference to said primary system (50) is retrieved from multiple data-bases (150) for computing spectrum access, and wherein each of said multiple databases are allocated a fraction of the interference margin (I_Δ

,p), most advantageously for each primary system (50) test point (P).

10. The method according to claim 9, wherein the multiple data-bases (150) that are used to compute spectrum access are configured to trade the fractions of the interference margins (I_Δ

,p) they possess.

11. The method according to claim 10, wherein a central geolocation database (150) is

12. The method according to claim 11, wherein the secondary system (10) is configured to allocate interference margins (I_Δ

,p) and compute the allowed transmission power for each transmitter it controls.

13. The method according to claim 6, wherein a central database (150) is configured to allocate the interference margins (I_Δ

,p) and compute the power density (P_d,i) that a secondary system (10) may use.

14. The method according to claim 6, wherein the secondary system (10) is configured to receive information of the power density (P_d,i) per area it can emit, and wherein the secondary system (10) is also configured to allocate the transmission power for each of its transmitters (22) by comparing the footprint (A_foot,i) of each particular transmitter (22).

15. A system (70) for controlling the aggregate interference of a secondary system (10) in a cognitive radio network, said system comprising:

a pre-programmed computational device, configured for computing the aggregate interference of a secondary system (10) in a radio network and responsive to results of said computation, for controlling the aggregate interference of said secondary system, said computational device preprogrammed for;

computing a power density (P_d,i) , a footprint (A_foot,i) and a service area (A_i) for each of a plurality of cells (100) of the secondary system (10) that satisfy an interference constraint at a given point (P) in a primary system (50), said computing performed in such a manner that;

said power density (P_d,i) is computed as a secondary transmitter density (ρ

_i) for each of said plurality of cells (100) multiplied with a secondary user power (P_SU,i) of each corresponding respective cell (100); and

said footprint (A_foot,i) is computed as an inverse of the secondary transmitter density (ρ

_i) for each of said plurality of cells (100);

responsive to computing said power density (P_d,i) for each of said plurality of cells (100), said computational device summing the power densities (P_d,i) for all said plurality of cells (100) for the point (P) weighted by an aggregated link gain (∫

_Aig_a^mda) of secondary user (SU) coverage areas (A_i) and shadow fading (E{x^m}); and

said computational device using the sum of the power density at the point (P) to compute an aggregate interference in order to display which power level a new secondary system (10) is allowed to use in a given cell (100).