METHOD OF COMBINED USER AND COORDINATION PATTERN SCHEDULING OVER VARYING ANTENNA AND BASE-STATION COORDINATION PATTERNS IN A MULTI-CELL ENVIRONMENT

• US 20100041407A1
• Filed: 08/10/2009
• Published: 02/18/2010
• Est. Priority Date: 08/13/2008
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Ramprashad, Sean A., Caire, Giuseppe, Papadopoulos, Haralabos
• Granted Patent: US 8,229,443 B2
• Time in Patent Office: Days
• US Class Current: 455/446
• CPC Class Codes: H04W 16/28 using beam steering
• CPC Class Codes: H04W 28/16 Central resource management; Negotiation of resources or communication parameters, e.g. negotiating bandwidth or QoS [Quality of Service]

Abstract

A method and system is disclosed herein for scheduling in a multi-cell environment. In one embodiment, the system comprises a plurality of user terminals; a plurality of base stations to communicate with the plurality of user terminals, wherein the plurality of antennas from the base stations are grouped into coordination patterns that specify which antennas operate together as a cluster to coordinate transmissions with a subset of the plurality of user terminals, and further wherein defined pairs of the antenna sets and associated user sets vary over transmission resources based on coordination pattern changes such that different sets of antennas in the plurality of antennas are grouped together on different resources to coordinate transmissions to different subsets of users; and at least one controller to execute at least one scheduling algorithm to schedule transmissions with user terminals by specifying which user terminal to schedule for service by which sets of antennas and on which transmission resource and with what transmission rate.

Claims

1. A wireless communication system comprising:

a plurality of user terminals;

a plurality of antennas to communicate with the plurality of user terminals, wherein the plurality of antennas are grouped into coordination patterns that specify which antennas operate together as a cluster to coordinate transmissions with a subset of the plurality of user terminals, and further wherein the defined pairs of the antenna sets and associated user sets vary over transmission resources based on coordination pattern changes such that different sets of antennas in the plurality of antennas are grouped together at different times to coordinate transmissions to different subsets of users; and

at least one controller to execute at least one scheduling algorithm to schedule transmission with user terminals by specifying which user terminal to schedule for service by which set of antennas and on which transmission resource and with what transmission rate.

2. The wireless communication system defined in claim 1 wherein which user terminals are scheduled and the rates to user terminals are scheduled jointly over the coordination patterns.

3. The wireless communication system defined in claim 1 wherein which user terminals are scheduled, the rates to user terminals, and the coordination pattern used are scheduled jointly.

4. The wireless communication system defined in claim 1 wherein the antennas are located at one or more base-stations.

5. The wireless communication system defined in claim 1 wherein clusters of antennas and the users each cluster serve, as defined by the coordination pattern, vary over transmission resources defined in part based on time.

6. The wireless communication system defined in claim 1 wherein clusters of antennas and the users each cluster serve, as defined by the coordination pattern, vary over transmission slots defined in part based on frequency.

7. The wireless communication system defined in claim 1 wherein a rate for at least one user terminal is based on average rates the one user terminal determined in part from rates given to that user over all possible clusters of antennas over all possible transmission resources.

8. The wireless communication system defined in claim 7 wherein the at least one controller is operable to receive information indicative of the average rate for user terminals to which they provide rates.

9. The wireless communication system defined in claim 1 wherein one controller attempts to maximize a sum of weighted average rates of a set of user terminals to be served.

10. The wireless communication system defined in claim 9 wherein weights used to generate the weighted average rates are selected to give each user terminal in the set of user terminals a determined share of the rate available from the controller.

11. The wireless communication system defined in claim 9 wherein weights used to generate the weighted average rates are based on an estimate of the rate a user terminal has received up to a specified scheduling event.

12. The wireless communication system defined in claim 1 wherein the average rate is determined over a number of coordination patterns by a windowed average of rates that have been given to a user terminal over a given interval time by clusters of antennas in the patterns.

13. The wireless communication system defined in claim 1 wherein the at least one controller comprises a plurality of controllers and controllers in the plurality of controllers exchange information with each other to indicate what rate was given to user terminals in the specified periods of time.

14. The wireless communication system defined in claim 13 wherein all controllers in the plurality of controllers that provide a user terminal with a transmission rate exchange with each other rate information indicative of the rate an individual controller provided the user terminal.

15. The wireless communication system defined in claim 13 wherein at least one of the controllers in the plurality of controllers broadcasts the average rate of one of the user terminals to other controllers based on one of more of its own rate information and exchanged rate information which are indicative of rates provided the one user terminal by clusters of antennas in the plurality of clusters of antennas.

16. The wireless communication system defined in claim 1 wherein the at least one controller comprises a plurality of controllers and at least one of the plurality of controllers is part of one of the plurality of base stations.

17. A method comprising:

varying clusters of antennas into new coordination patterns that specify which antennas operate together as a cluster to coordinate transmissions with a subset of the plurality of user terminals, wherein clusters vary over transmission resources based on coordination pattern changes such that different sets of antennas in the plurality of antennas are grouped together at different times to coordinate transmissions to different subsets of users; and

executing at least one scheduling algorithm to schedule transmissions with user terminals by specifying which user terminal to schedule in which cluster and on which transmission resource and transmission rates for the user terminals.

18. The method defined in claim 17 wherein executing at least one scheduling algorithm comprises, for each coordination cluster specified in a coordination pattern,

receiving information to implement a scheduling criterion;

creating information to make a scheduling decision;

obtaining an estimate of a rate the system using the set of antennas can support to a user terminal;

selecting the user terminal for scheduling based on the rate estimate;

determining the rate a user is to be given if it is scheduled.

25. The method defined in claim 17 where the antennas are at least located at or controlled by a plurality of base-stations.

19. A method for scheduling user terminals in a wireless communication system having a plurality of user terminals and a plurality of antennas that are grouped based on coordination patterns that specify which antennas operate together as a cluster to coordinate transmissions with a subset of the plurality of user terminals, the method comprising:

for each coordination cluster specified in a coordination pattern, performing operations including

receiving information required to implement a scheduling criterion;

creating information to make a scheduling decision;

obtaining an estimate of a rate the system using the set of antennas can support to a user terminal;

selecting the user terminal for scheduling based on the rate estimate;

determining the rate a user is to be given if it is scheduled.

20. The method defined in claim 19 further comprising obtaining information on which coordination pattern to use.

21. The method defined in claim 19 further comprising determining which coordination pattern to use.

22. The method defined in claim 19 wherein the estimate of a rate a group of antennas can support to a user terminal, as determined by a scheduler, is based on one selected from a group consisting of an estimate of the effective Signal to Interference and Noise Ratios (SINRs) of user terminals derived from channel state information, the channel state information between a user and associated serving antennas, and an estimate of rates supported to each user if transmissions are sent jointly to each in a plurality of subsets of users.

23. The method defined in claim 19 further comprising updating and storing information required for future scheduling decisions regarding the user terminal.

24. The method defined in claim 23 further comprising sending the information to a central repository.

26. The method defined in claim 19 where the antennas are located at and/or controlled by a plurality of base-stations.