Dynamic DCH allocation methodology for packet data services in a wireless communications system

• US 20040017795A1
• Filed: 07/24/2002
• Published: 01/29/2004
• Est. Priority Date: 07/24/2002
• Status: Active Grant

• Current Assignee: RPX Corporation
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Chuah, Mooi Choo, Abraham, Santosh P., Chou, Ching-Roung, Sapiano, Philip Charles, Sommars, Steven E.
• Granted Patent: US 7,206,286 B2
• Time in Patent Office: Days
• US Class Current: 370/348
• CPC Class Codes: H04W 36/26 by agreed or negotiated communication parameters

Abstract

In a UMTS network, each packet data service user requires a dedicated channel (DCH) to transmit at high data rates. However, the number of DCHs available is small due to code and power limitations. Thus many users will have to be allocated the same DCH on a time sharing basis. Such sharing will not impact the quality of service for users whose applications are not delay sensitive and whose traffic generation pattern toggles between transmit and idle states. Such applications include web browsing, FTP sessions and E-mail. The present invention discloses four algorithms that can be used to dynamically allocate DCH channels to a contending user based on the user'"'"'s need according to its traffic generation. One embodiment of the invention discloses a methodology of allocating user channels for packet data services in a wireless communications network, a first type channel having a given data rate and a second type channel having a lower data rate, including the steps of determining an estimated bandwidth requirement for the packet data services, switching a user to the second channel type from said first channel type if said estimated bandwidth requirement is below a first threshold, and switching a user to the first channel type from said second channel type if the estimated bandwidth requirement is greater than a second threshold. Another embodiment discloses methodology of allocating user channels for packet data services in a wireless communications network, a first type channel having a given data rate and a second type channel having a lower data rate, comprising the steps of providing an inactivity timer per user, and switching from the first channel type to said second channel type depending on a state of said inactivity timer.

Claims

1. A method of allocating user channels for packet data services in a wireless communications network, a first type channel having a given data rate and a second type channel having a lower data rate, comprising the steps of:

determining an estimated bandwidth requirement for said packet data services;

switching a user to said second channel type from said first channel type if said estimated bandwidth requirement is below a first threshold; and

switching a user to said first channel type from said second channel type if said estimated bandwidth requirement is greater than a second threshold.

2. The method of claim 1, wherein switching to said first channel type from said second channel type occurs only if said first channel type is available.

3. The method of claim 1, wherein said estimated bandwidth requirement is based on the number of uplink and downlink data units in a given interval.

4. The method of claim 3, wherein said estimated bandwidth requirement is further based on queue length of an associated buffer.

5. The method of claim 4, wherein said estimated bandwidth requirement is further filtered.

6. The method of claim 5, wherein said filter emulates a low pass filter.

7. The method of claim 1, wherein said estimated bandwidth requirement is based on the number of downlink arrivals during a given interval and queue length of an associated buffer at the beginning of the interval.

8. The method of claim 7, wherein said estimated bandwidth requirement is further filtered.

9. The method of claim 1, wherein said filter is an exponential averaging filter.

10. The method of claim 1, wherein said first type channels are selected from the group consisting of dedicated channels and active state channels and wherein said second type channels are selected from the group consisting of forward access channels and dormant state channels.

11. The method of claim 1, wherein said second threshold is based on a proportion of downloadable object sizes.

12. The method of claim 1, wherein said first threshold value is chosen to minimize transitions from FACH to DCH from packet bursts.

13. The method of claim 1, wherein said second threshold is chosen to reflect a lower bound on occupancy of a DCH.

14. A method of allocating user channels for packet data services in a wireless communications network, a first type channel having a given data rate and a second type channel having a lower data rate, comprising the steps of:

providing an inactivity timer per user;

switching from said first channel type to said second channel type depending on a state of said inactivity timer.

15. The method of claim 14, wherein said step of switching takes place when said inactivity timer reaches a predetermined threshold.

16. The method of claim 14, wherein said step of switching further includes the step of scanning the inactivity period of a number of users utilizing said first type of channel and switching a user having a highest inactivity channel to said second type channel.

17. The method of claim 15, further including the step of scanning the inactivity period of a number of users utilizing said first type of channel and switching a user having a highest inactivity channel to said second type channel if none of said users have reached said predetermined threshold.

18. An apparatus for allocating user channels for packet data services in a wireless communications network, a first type channel having a given data rate and a second type channel having a lower data rate, said apparatus comprising:

means for determining an estimated bandwidth requirement for said packet data services;

means for switching a user to said second channel type from said first channel type if said estimated bandwidth requirement is below a first threshold; and

means for switching a user to said first channel type from said second channel type if said estimated bandwidth requirement is greater than a second threshold.

19. The apparatus of claim 19, wherein said apparatus is included in a radio network controller.