Method and apparatus for scheduling transmissions in a communication system

• US 20020183066A1
• Filed: 10/10/2001
• Published: 12/05/2002
• Est. Priority Date: 04/12/2001
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Pankaj, Rajesh K.
• Granted Patent: US 6,807,426 B2
• Time in Patent Office: Days
• US Class Current: 455/453
• CPC Class Codes: H04W 72/54 based on quality criteria

Abstract

Method and apparatus for a generalized scheduler for scheduling transmissions in a communications system. The scheduler is defined by a priority function of the channel condition and fairness criteria. The generalized scheduler is adapted to apply a variety of combinations of channel condition metrics and user fairness metrics. The scheduler distinguishes among classes of users, allowing individual processing per class. In one embodiment, a system controller receives a Delivery Priority Parameter (DPP) for each of a plurality of users, and maps each DPP to a corresponding common Mapped Priority Parameter (MPP). An operating point is determined and a corresponding MPP value for each of the users is applied to schedule transmissions.

Claims

1. In a wireless communication system a scheduling method, comprising:

receiving channel condition indicators from a plurality of mobile users, wherein the channel condition indicators correspond to forward link communications;

determining a fairness indicator as a function of throughput to the plurality of mobile users; and

determining a transmission schedule for the plurality of mobile users, wherein the transmission schedule is a function of the channel condition indicators and fairness indicators.

2. The method as in claim 1, determining a transmission schedule further comprises:

calculating scheduling indicators for the plurality of mobile stations as a function of the channel condition indicator and the fairness indicator; and

selecting at least one of the plurality of mobile stations for a next transmission based on the scheduling indicators.

3. The method as in claim 2, wherein determining the transmission schedule further comprises:

calculating a function of the channel condition indicator as;

A_i(t)=B(t)/B_—

AVE_i(t) for i=1, . . . N,

wherein Ai(t) is a function of the channel condition indicator for an ith mobile station, B_i(t) is the channel condition indicator from the ith mobile station at time t, B_AVE_i(t) is an average value of channel condition indicators recently received from the ith mobile station, and N is the total number of mobile stations in the plurality of mobile stations.

4. The method as in claim 3, wherein the channel condition indicator is a data rate control request, and the average value of channel condition indicators is a filtered data rate control request from the ith mobile station.

5. The method as in claim 4, wherein calculating a function of the channel condition indicator comprises:

calculating the filtered data rate control request from the ith mobile station at time t as;

B_—

AVE_i(t+1)=B_—

AVE_i(t)[1−

(1/T_c)]+B_i(t)[1/T_c],

wherein Tc is a fairness time period.

6. The method as in claim 5, wherein calculating a function of the channel condition indicator further comprises:

assigning a weight to each of the recently received data rate control requests.

7. The method as in claim 2, wherein calculating scheduling indicators comprises:

for each of the plurality of mobile stations, determining a ratio of a corresponding channel condition indicator to a corresponding fairness indicator.

8. The method as in claim 1, wherein for each mobile station the fairness indicator is a fraction of time the mobile station was served during a fairness time period.

9. A program embodied on a computer-readable medium containing computer-executable instructions, comprising:

a first set of instructions for processing channel condition indicators received from a plurality of mobile users;

a second set of instructions for determining a fairness indicator as a function of throughput to the plurality of mobile users; and

a third set of instructions for determining a transmission schedule for the plurality of users as a function of the channel condition indicators and the fairness indicators.

10. The program as in claim 9, the function of the channel condition indicators and the fairness indicators balances the channel condition indicators with the fairness indicators.

11. In a wireless communication system, an access network, comprising:

receiving means for receiving channel condition indicators from a plurality of mobile users, wherein the channel condition indicators correspond to forward link communications;

means for determining a fairness indicator as a function of throughput to the plurality of mobile users; and

means for determining a transmission schedule for the plurality of mobile users, wherein the transmission schedule is a function of the channel condition indicators and fairness indicators.

13. The method as in claim 12, further comprising:

for each of the plurality of mobile users, applying a mapped priority parameter value corresponding to the operating point; and

determining a delivery priority parameter value corresponding to the mapped priority parameter value.

14. The method as in claim 13 wherein a first delivery priority parameter is a desired time allotment.

15. The method as in claim 13 wherein a second delivery priority parameter is a desired throughput.

16. The method as in claim 13 wherein a third delivery priority parameter is a desired delay.

19. The apparatus as in claim 18, wherein the computer-readable instructions further implement:

applying the operating point to each of the plurality of mobile users, wherein the operating point determines mapped priority parameter values corresponding to each of the plurality of mobile users.

20. The apparatus as in claim 19, wherein the computer-readable instructions further implement:

scheduling the plurality of mobile users according to the operating point using the mapped priority parameter values.

12. A method for scheduling data transmissions in a wireless communication system, comprising:

receiving a value for a delivery priority parameter from each of a plurality of mobile users;

if any of the delivery priority parameters are different types, mapping each delivery priority parameter to a mapped priority parameter; and

determining an operating point based on the mapped priority parameters of the plurality of mobile users.

17. A system controller in a wireless communication system, comprising:

means for receiving a delivery priority parameter from each of a plurality of mobile users;

means for mapping each delivery priority parameter to a mapped priority parameter; and

means for determining an operating point based on the mapped priority parameters of the plurality of mobile users.

18. An apparatus in a wireless communication system, comprising:

a processing element; and

a memory storage element coupled to the processing element, the memory storage element adapted for storing computer-readable instructions for implementing;

receiving a delivery priority parameter from each of a plurality of mobile users;

mapping each delivery priority parameter to a mapped priority parameter; and

determining an operating point based on the mapped priority parameters of each the plurality of mobile users.

21. A wireless infrastructure apparatus, comprising:

a channel scheduling unit adapted for scheduling transmissions to a plurality of receivers; and

a fairness selector adapted to apply a plurality of received delivery priority parameters receiver from the plurality of receivers.

22. The apparatus as in claim 21, wherein the channel scheduling unit schedules transmissions based on the plurality of delivery priority parameters and channel condition indicators received from the plurality of receivers.