Intercell interference mitigation
View Patent ↗Methods and apparatus are described for mitigating intercell interference in wireless communication systems utilizing substantially the same operating frequency band across multiple neighboring coverage areas. The operating frequency band may be shared across multiple neighboring or otherwise adjacent cells, such as in a frequency reuse one configuration. The wireless communication system can synchronize one or more resource allocation regions or zones across the multiple base stations, and can coordinate a permutation type within each resource allocation zone. The base stations can coordinate a pilot configuration in each of a plurality of coordinated resource allocation regions. Subscriber stations can be assigned resources in a coordinated resource allocation region based on interference levels. A subscriber station can determine a channel estimate for each of multiple base stations in the coordinated resource allocation region to mitigate interference.
1. A method of intercell interference mitigation, the method comprising:
receiving, at a base station, a channel quality indicator value from a subscriber station;
analyzing the channel quality indicator value;
determining, based on the channel quality indicator value, a selected resource allocation region in a communication time frame from a plurality of resource allocation regions that includes at least one coordinated downlink resource allocation region, the coordinated downlink resource allocation region comprising multiple downlink resources that are coordinated between the base station and at least one other base station for intercell interference mitigation; and
assigning the subscriber station to the selected resource allocation region.
2. The method of claim 1 , wherein the channel quality indicator value comprises a signal to interference ratio (SIR) value of a communication channel between the base station and the subscriber station.
3. The method of claim 1 , wherein the channel quality indicator value comprises an interference to noise ratio (INR) value of a communication channel between the base station and the subscriber station.
4. The method of claim 1 , wherein the channel quality indicator value comprises a signal to interference ratio (SIR) value and an interference to noise ratio (INR) value of a communication channel between the base station and the subscriber station.
5. The method of claim 4 , wherein determining the selected resource allocation region comprises:
comparing the SIR value to a first threshold value; comparing the INR value to a second threshold value; and
determining a coordinated downlink resource allocation region as the selected resource allocation region if the first threshold value exceeds the SIR value and the INR value exceeds the second threshold value.
6. A method of intercell interference mitigation, the method comprising:
classifying a subscriber station as interference limited; and
allocating a downlink resource to the subscriber station within a coordinated resource zone of a downlink subframe.
7. The method of claim 6 , further comprising synchronizing a timing of the coordinated resource zone across multiple sectors of a base station.
8. The method of claim 6 , further comprising synchronizing a timing of the coordinated resource zone across multiple base stations.
9. The method of claim 6 , further comprising synchronizing pilot signal frequency and timing across a plurality of base stations in the coordinated resource zone.
10. The method of claim 6 , further comprising transmitting information to the subscriber station in the downlink resource.
11. The method of claim 6 , wherein allocating the downlink resource comprises specifying a predetermined modulation scheme common throughout the coordinated resource zone.
12. A base station configured for interference mitigation; the base station comprising:
an administrative manager configured to coordinate at least one downlink resource allocation region within a communication time frame with a neighboring base station;
a subscriber station capabilities monitor configured to store capabilities of at least one subscriber station within a coverage area of the base station;
a coordinated downlink zone manager configured to determine a resource allocation region from a plurality of resource allocation regions for a subscriber station based at least in part on capabilities of the subscriber station stored in the subscriber station capabilities monitor; and
a scheduler configured to schedule information for the subscriber station in the resource allocation region.
13. The base station of claim 12 , further comprising:
a permutation manager configured to store a permutation base and permutation type utilized by the base station, and wherein the scheduler is configured to schedule the information based on the permutation base and permutation type.
14. The base station of claim 12 , wherein the administrative manager is configured to coordinate a pilot configuration in a coordinated downlink resource allocation region with the neighboring base station.
15. The base station of claim 12 , wherein the coordinated downlink zone manager is configured to assign the subscriber station to a coordinated downlink resource allocation region based on an interference analysis.
16. The base station of claim 15 , wherein the coordinated downlink zone manager performs interference analysis based at least in part on a channel quality indicator value received from the subscriber station.