Inter-cell interference co-ordination

• US 8,325,621 B2
• Filed: 04/20/2007
• Issued: 12/04/2012
• Est. Priority Date: 04/20/2007
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Simonsson, Arne, Furuskär, Anders
• Primary Examiner(s): RIYAMI, ABDULLAH A
• Application Number:
  US12/595,751
• Publication Number:
  US 20100128618A1
• Time in Patent Office: 2,055 Days
• Field of Search: 455/63.1, 455/63.3, 455/67.11, 455/450, 455/434, 455/442, 455/446, 455/423, 455/424, 455/500, 455/525, 455/513, 455/522, 370/229, 370/230, 370/252, 370/310, 370/318, 370/320, 370/330, 370/335, 370/468, 375/260
• US Class Current: 370/252
• CPC Class Codes: H04B 17/345 Interference values signal-to-interference ratio [SIR] or carrier-to-interference ratio [CIR] H04B17/336
• CPC Class Codes: H04B 17/373 Predicting channel quality or other radio frequency [RF] parameters
• CPC Class Codes: H04W 52/146 Uplink power control
• CPC Class Codes: H04W 52/243 taking into account interferences
• CPC Class Codes: H04W 52/40 during macro-diversity or soft handoff

Abstract

According to the present invention, a method in a base station is provided for predicting interference contribution, when scheduling an uplink data packet transmission from a first user equipment. The first user equipment is connected to the base station. The first user equipment is in the neighbor of a neighboring cell served by a neighboring base station. The method comprises the steps of: Obtaining signal strength measurements regarding the first user equipment. The signal strength measurements are based on a signal between the first user equipment and the neighboring base station; Receiving a resource scheduling request regarding the first user equipment for the uplink data packet transmission; Scheduling uplink resources for the requested uplink data packet transmission; Determining transmission power to be used for the scheduled uplink resources, and: Estimating an interference prediction contribution based on the determined transmission power and the obtained signal strength.

Claims

1. A method in a base station for predicting interference contribution, when scheduling an uplink data packet transmission from a first user equipment being connected to the base station, the first user equipment being in the neighborhood of a neighboring cell served by a neighboring base station, the method comprising the steps of:

obtaining signal strength (SS) measurements regarding the first user equipment, wherein each signal strength measurement of the signal strength measurements is based on a signal between the first user equipment and the neighboring base station;

receiving a resource scheduling request regarding the first user equipment for the uplink data packet transmission;

scheduling uplink resources for the requested uplink data packet transmission;

determining transmission power (P_SUR) to be used for the scheduled uplink resources;

estimating an interference prediction contribution (I_PC) for the neighboring cell based on the determined transmission power (P_SUR), and the obtained signal strength (SS) measurements, and a path loss between the neighboring base station and the first user equipment; and

sending the estimated interference prediction contribution (I_PC) to the neighboring base station.

2. The method of claim 1, wherein the base station is aware of power (P_S) that the neighboring cell uses for broadcasting signals, and wherein the step of estimating is performed by calculating the interference prediction contribution by means of the formula [I_PC=P_SUR−

(P_S−

SS)], where P_S−

SS represents the path loss.

3. The method of claim 1, wherein the estimated interference prediction contribution is used by the neighboring base station in scheduling link adaptation or closed loop power control.

4. The method of claim 1, wherein the step of sending the estimated interference prediction contribution is performed only if the interference prediction contribution is above a certain threshold.

5. The method of claim 1, wherein the step of sending the estimated interference prediction contribution is performed only if the uplink transmission is estimated to have a duration exceeding a predetermined time.

6. The method of claim 1, wherein the step of sending the estimated interference prediction contribution is performed before or at the same time as a scheduling grant is sent to the first user equipment.

7. The method of claim 1, wherein at least one second user equipment is connected to the base station and wherein all the steps are performed also for each of the at least one second user equipment.

8. The method of claim 7, further comprising the steps of:

compiling interference prediction contributions per resource and time for all of the at least one scheduled second user equipment in a connected cell; and

sending the compiled interference prediction contribution to the neighboring base station.

9. The method of claim 8, wherein the step of sending the compiled interference prediction contribution is performed when an update of the scheduling is performed.

10. The method of claim 1, wherein the step of obtaining signal strength measurements is more frequent than the step of receiving resource scheduling requests, and further comprising using the latest available signal strength measurements for the step of estimating the interference prediction contribution.

11. The method of claim 1, wherein the base station receives an interference prediction contribution from a neighboring radio base station concerning at least one other user equipment that has been scheduled an uplink resource by the neighboring radio base station.

12. The method of claim 11, further comprising the step of measuring the interference on the uplink resources used by the other user equipment to the neighboring base station.

13. The method of claim 12, further comprising combining the measured interference with the interference prediction contribution received from the neighboring base station, to refine the interference prediction contribution received from the neighboring base station.

14. The method of claim 11, wherein the base station receives interference prediction contributions from each of a number of neighboring radio base stations concerning other user equipments requesting uplink resources from the respective neighboring radio base stations, and further comprising the step of compiling a total interference prediction per resource.

15. The method of claim 14, wherein the step of compiling a total interference prediction per resource is performed by summarizing all the received interference predictions per resource.

16. An arrangement in a base station, the base station configured to be connected to a first user equipment being in the neighborhood of a neighboring cell served by a neighboring base station, the base station arrangement comprising:

a receiving unit configured to obtain signal strength (SS) measurements regarding the first user equipment, wherein each signal strength measurement of the signal strength measurements is based on a signal between the first user equipment and the neighboring base station;

the receiving unit further being configured to receive a resource scheduling request regarding the first user equipment for an uplink data packet transmission;

the base station arrangement further comprising a scheduling unit configured to schedule uplink resources for the requested uplink data packet transmission;

the scheduling unit being further configured to determine transmission power (P_SUR) to be used for the scheduled uplink resources;

the base station arrangement further comprising an interference prediction estimation unit configured to estimate an interference prediction contribution (I_PC) for the neighboring cell based on the determined transmission power, and the obtained signal strength measurements, and a path loss between the neighboring base station and the first user equipment;

the base station arrangement further comprising a sending unit configured to send the estimated interference prediction contribution to the neighboring base station.

17. The base station arrangement of claim 16, wherein the base station is aware of power (P_S) that the neighboring cell uses for broadcasting signals, and wherein the interference prediction estimation unit is further configured to calculate the interference prediction contribution by means of the formula [I_PC=P_SUR−

(P_S−

SS)].

18. The base station arrangement of claim 16, wherein the receiving unit is further configured to receive an interference prediction contribution estimated by a neighboring radio base station concerning another user equipment that has been scheduled an uplink resource by the neighboring radio base station.

19. The base station arrangement of claim 18, wherein the base station arrangement is configured to use the estimated interference prediction contribution received from the neighboring cell in scheduling link adaptation or closed loop power control.

20. The base station arrangement of claim 19, wherein the base station arrangement is configured to measure the interference on the uplink resources used by the other user equipment of the neighboring base station, and to combine the measured interference with the interference prediction contribution received from the neighboring base station for the other user equipment, to refine the interference prediction contribution received from the neighboring base station.