Method and apparatus for rapid assignment of a traffic channel in digital cellular communication systems

• US 6,366,779 B1
• Filed: 09/22/1998
• Issued: 04/02/2002
• Est. Priority Date: 09/22/1998
• Status: Expired due to Term

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Grob, Matthew S., Bender, Paul E., Karmi, Gadi
• Primary Examiner(s): Urban, Edward F.
• Application Number:
  US09/158,697
• Time in Patent Office: 1,288 Days
• Field of Search: 455/434, 455/450, 455/464, 455/509, 455/514, 455/515, 455/500, 370/335, 370/334, 370/336, 370/333
• US Class Current: 455/450
• CPC Class Codes: H04W 48/20 Selecting an access point
• CPC Class Codes: H04W 72/04 Wireless resource allocation
• CPC Class Codes: H04W 74/08 Non-scheduled access, e.g. ALOHA hybrid access H04W74/02
• CPC Class Codes: H04W 76/10 Connection setup

Abstract

A method and apparatus for rapidly assigning traffic channels to a plurality of mobile stations in a wide area high-speed packet data cellular communication system. Mobile stations transmit access probes on randomly selected access channels to selected base stations to initiate traffic channel assignments. The access probe comprises a pilot preamble, a traffic channel request, and a pilot/data request channel (DRC). The pilot preamble allows the selected base station to easily detect the access probe transmission. The traffic channel request includes data that identifies the mobile station. Immediately after transmitting the traffic channel request, the mobile station begins communicating with the base station on both the forward and reverse communication links. The selected base station immediately supervises the mobile station'"'"'s transmission power. The mobile station selects from a group of available power control sub-channels. The mobile station selects an available channel and an associated power control sub-channel from the list. In another alternative embodiment, the base station, and not the mobile station, initiates the traffic channel assignment process. A base station controller instructs all base stations within the mobile station'"'"'s paging radius to transmit a page message on the forward link. The mobile station continuously monitors the forward link and responds to pages addressed to its associated MSI. When a page to the mobile station is detected, the mobile station initiates a traffic channel request. In addition, the mobile station immediately monitors the power control sub-channel that it identified in the detected page message.

Claims

1. A method of establishing a communication link, comprising the steps of:

a) randomly selecting a reverse channel for transmitting a traffic channel request from a requesting mobile station to a selected base station;

b) transmitting a traffic channel request to the selected base station using a selected access channel of the reverse channel selected in step (a), wherein the transmission of the traffic channel request includes transmitting a pilot preamble to facilitate detection of the traffic channel request;

wherein the selected base station advertises a group of available power control sub-channels, and wherein the requesting mobile station selects one of the available power control sub-channels for use in subsequent communications with the selected base station.

2. The method of establishing a communication link of claim 1, further comprising communicating with the selected base station using both the selected reverse channel and an associated corresponding forward channel after transmitting the traffic channel request.

3. The method of establishing a communication link of claim 1, wherein the transmitting step (b) comprises sending an access probe to the selected base station over an access channel of the selected reverse channel.

4. The method of claim 3, wherein the access probe comprises a pilot preamble, a traffic channel request, and a pilot/data request channel (DRC) field.

5. The method of claim 4, wherein the pilot preamble comprises a known sequence of data that is easily detected by the selected base station.

6. The method of claim 4, wherein the traffic channel request includes a transaction identifier, a reference pilot, a pilot strength indicator, and a timer status field.

7. The method of claim 4, wherein the DRC includes traffic channel data rate information that is used by the requesting mobile station to request the maximum data rate from the selected base station that the requesting mobile station can reliably demodulate.

8. The method of claim 4, wherein the mobile station continues to transmit the pilot/DRC field for a time period defined by an access probe tail.

9. The method of claim 8, wherein the time period defined by the probe tail is advertised by the selected base station on an associated corresponding forward channel.

10. The method of claim 4, further comprising the step of receiving a traffic channel assignment message that is transmitted by the selected base station on an associated corresponding forward channel.

11. The method of claim 10 wherein the traffic channel assignment message is transmitted at a data rate determined by the requesting mobile station and defined in the DRC field.

12. The method of claim 3, wherein the access probe is masked using a long code cover comprising an access channel cover and a mobile station identifier (MSI) cover code.

13. The method of claim 3, wherein the requesting mobile station transmits a sequence of the access probes of increasing power until the traffic channel request attempt is either successful or the traffic channel request attempt terminates.

14. The method of claim 1, wherein the traffic channel request includes identifying data that identifies the requesting mobile station to the selected base station.

15. The method of claim 6, wherein the identifying data comprises a mobile station identifier (MSI) previously assigned to the requesting mobile station during a registration procedure.

16. The method of claim 1, wherein the wireless data communication system comprises a high-speed CDMA system.

17. The method of claim 16, wherein the high-speed CDMA system provides packet data connectivity between a plurality of base stations and a plurality of mobile stations.

18. The method of claim 1, wherein the requesting mobile station transmits the traffic channel request to a base station that is transmitting the strongest received pilot signal to the requesting mobile station.

19. The method of claim 1, wherein the selected base station advertises a list of available traffic channels and associated corresponding available power control sub-channels, and wherein the requesting mobile station selects one of the available traffic channels and sub-channels for use in subsequent communications with the selected base station.

20. A method of establishing a communication link between a mobile station and a base station in a wireless data communication system having a plurality of base stations and a plurality of mobile stations, wherein transmissions from the base stations to the mobile stations are made via forward radio channels and wherein transmissions from the mobile stations to the base stations are made via reverse radio channels, each reverse channel having an associated and corresponding forward channel in a one-to-one relationship, and wherein each forward channel includes a control channel and a plurality of forward traffic channels, and wherein each reverse channel includes at least one access channel and a plurality of reverse traffic channels, comprising the steps of:

a) directing all base stations within a selected mobile station'"'"'s paging radius to transmit page messages to the selected mobile station via the control channel;

b) monitoring the control channel page messages received by the selected mobile station;

c) detecting whether a page message is addressed to the selected mobile station;

d) selecting a reverse traffic channel to use for transmitting a traffic channel request whenever the selected mobile station detects a page message addressed to it in step (c);

e) transmitting a traffic channel request to a selected base station using the reverse traffic channel selected in step (d); and

f) communicating with the selected base station using both the selected reverse traffic channel and an associated corresponding forward traffic channel.

21. The method of establishing a communication link of claim 20, wherein the communicating step (f) occurs immediately after transmitting the traffic channel request in step (e).

22. The method of establishing a communication link of claim 20, wherein the transmitting step (e) comprises sending an access probe to the selected base station using an access channel of the selected reverse channel.

23. The method of claim 22, wherein the access probe comprises a pilot preamble, a traffic channel request, and a pilot/data request channel (DRC) field.

24. The method of claim 20 wherein the selected base station advertises a group of available power control sub-channels, and wherein the selected mobile station selects one of the available power control sub-channels for use in subsequent communications with the selected base station.

25. The method of claim 20, wherein the selected base station advertises a list of available traffic channels and associated corresponding available power control sub-channels, and wherein the selected mobile station selects one of the available traffic channels and sub-channels for use in subsequent communications with the selected base station.