Link-efficiency based scheduling in radio data communications systems

• US 6,236,656 B1
• Filed: 03/19/1998
• Issued: 05/22/2001
• Est. Priority Date: 03/19/1998
• Status: Expired due to Term

• Current Assignee: Optis Cellular Technology LLC (Brevet Capital)
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Westerberg, Erik, Forslöw, Jan
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): JONES, PRENELL P
• Application Number:
  US09/044,357
• Time in Patent Office: 1,160 Days
• Field of Search: 370/395, 370/216, 370/429, 370/427, 370/470, 370/389, 370/517, 370/329, 370/337, 370/348, 370/349, 370/280, 370/416, 370/236, 370/347, 370/437, 370/460-462, 370/294, 370/401, 370/352, 379/114, 379/112, 455/406, 455/407, 455/452, 455/512-524, 455/38.1, 455/161.2, 455/166.2
• US Class Current: 370/395.4
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 76/20 Manipulation of established connections
• CPC Class Codes: H04W 88/08 Access point devices
• CPC Class Codes: H04W 92/12 between access points and access point controllers

Abstract

A system and method for scheduling packet transmissions, whereby a Base Station System (BSS) part provides scheduling-related information to a Switching System (SS) part for scheduling of LLC frames, which includes information about the total number of packet data service radio links in the cell, and for each user, the bandwidth per link. Consequently, the SS can determine the required link utilization and hence the transmission time for each data packet the SS submits for transmission over the radio links. As such, the SS can control all end-to-end QoS quantities for each data packet, and how these quantities are affected by the SS scheduling of the LLC frames to the BSS. In this way, the SS can completely control how QoS agreements with users are met.

Claims

1. In a wireless data communications system comprising a switching system, a base station and a plurality of individual user stations, wherein radio links extend from said user stations to said base station and said base station is disposed to selectively enable data transmissions over respective radio links, a method for scheduling said data transmissions comprising the steps of:

coupling specified information characterizing the efficiency of each of said links from said base station to said switching system; and

operating said switching system to submit a sequence of data units to said base station for transmission over respective radio links, each of said data units corresponding to one of said user stations, and said sequence being selectively ordered in response to said link efficiency information so that the transmission of each data unit fulfills a quality of service agreement of the user station corresponding thereto.

2. The method of claim 1, wherein:

said coupling step comprises coupling information to said switching system which comprises the total number of said radio links and, for each of said users, the bandwidth for each of said links.

3. The method of claim 1, wherein said switching system schedules said submitting of said sequence of said data units so as to maximize the number of said quality of service agreements which are fulfilled.

4. The method of claim 1, wherein said data units comprise packet data units.

5. The method of claim 1, wherein said wireless data communications system comprises a GPRS system, and said data units comprise IP packets.

6. The method of claim 1, wherein said data units comprise LLC packet data units.

7. The method of claim 1, wherein said wireless data communications system comprises a packet data wireless system.

8. The method of claim 1, wherein said wireless data communications system comprises a CDPD system.

9. The method of claim 1, wherein said wireless data communications system comprises a packet data service associated with an IS-95 system.

10. The method of claim 1, wherein said wireless data communications system comprises a packet data radio satellite communications system.

11. The method of claim 1, wherein said wireless data communications system is associated with a W-CDMA system.

12. The method of claim 1, wherein said wireless data communications system is a system associated with a wireless Asynchronous Transfer Mode (ATM) system.

13. The method of claim 1, wherein said links are included in a common cell.

14. A method for scheduling data transmissions in a wireless communications system, comprising the steps of:

a switching system reading in cell-based link efficiency information from a base station system;

determining whether a data queue length in said base station system is greater than a first predetermined value or less than a second predetermined value;

adjusting a load to compensate for at least one condition wherein said data queue length is greater than said first predetermined value or less than said second predetermined value;

sequencing an intended submission of data units for transmission so as to maximize a number of quality of service agreements to be fulfilled; and

submitting said sequence of said data units to said base station system.

15. The method of claim 14, further comprising the steps of:

said base station system determining whether said data queue includes at least one data unit;

if so, emptying said queue by data transmission;

measuring a throughput per link per user; and

compiling and conveying to said switching system said cell-based link efficiency information, including at least one value for said measured throughput per link per user, for a total number of links, and for a length of said queue.

16. The method of claim 15, further comprising the step of said base station system transmitting said data units to a plurality of users on a first-in-first-out basis.

17. The method of claim 14 or 15, wherein said cell-based link efficiency information includes a total number of links in a cell.

18. In a wireless communications system provided with a plurality of user stations, a system for scheduling data transmissions comprising:

a base station disposed to generate specified information characterizing the efficiency of each of a plurality of radio links extending from said user stations to said base station; and

a switching system disposed to receive said link efficiency information and operable to submit a sequence of selectively ordered data units to said base station for transmission over respective radio links, each of said data units corresponding to one of said user stations, said switching system being further operable to order said sequence in response to said link efficiency information so that the transmission of each data unit fulfills a quality of service agreement associated with its corresponding user station.

19. The system of claim 18, said base station system further operable to:

store said sequence of said data units in a queue; and

output for transmission said sequence of said data units from said queue on a first-in-first-out basis.

20. The system of claim 18, wherein said switching system is further operable to schedule submission of said sequence of said data units so as to maximize the number of said quality of service agreements, which are fulfilled.

21. The system of claim 18, wherein said data units comprise packet data units.

22. The system of claim 18, wherein said wireless data communications system comprises a GPRS system, and said data units comprise IP packets.

23. The system of claim 18, wherein said data units comprise LLC packet data units.

24. The system of claim 18, wherein said wireless data communications system comprises a packet data wireless system.

25. The system of claim 18, wherein said wireless data communications system comprises a CDPD system.

26. The system of claim 18, wherein said wireless data communications system comprises a packet data service associated with an IS-95 system.

27. The system of claim 18, wherein said wireless data communications system comprises a packet data radio satellite communications system.

28. The system of claim 18, wherein said wireless data communications system is associated with a W-CDMA system.

29. The system of claim 18, wherein said wireless data communications system is a system associated with a wireless ATM system.

30. The system of claim 18, wherein said links are included in a common cell.