Fast acquisition of traffic channels for a highly variable data rate reverse link of a CDMA wireless communication system

• US 6,928,064 B2
• Filed: 01/20/2004
• Issued: 08/09/2005
• Est. Priority Date: 12/17/1997
• Status: Expired due to Term

• Current Assignee: Intel Corporation
• Original Assignee: Tantivy Communications Incorporated (InterDigital, Inc.)
• Inventors: Proctor, James A. Jr.
• Primary Examiner(s): QURESHI, AFSAR M
• Application Number:
  US10/761,130
• Publication Number:
  US 20040208147A1
• Time in Patent Office: 567 Days
• Field of Search: 370/230, 370/233, 370/235, 370/329, 370/335, 370/336, 370/342, 370/441, 370/468, 370/479, 375/200
• US Class Current: 370/335
• CPC Class Codes: H04B 1/7075 with code phase acquisition
• CPC Class Codes: H04B 1/70754 Setting of search window, i.e. range of code offsets to be searched H04B1/70758 takes precedence
• CPC Class Codes: H04B 2001/70706 using a code tracking loop, e.g. a delay locked loop
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 2201/70709 with discontinuous detection
• CPC Class Codes: H04B 2201/70715 with application-specific features
• CPC Class Codes: H04B 7/2628 using code-division multiple access [CDMA] or spread spectrum multiple access [SSMA] H04B7/2618 takes precedence
• CPC Class Codes: H04J 13/0022 PN, e.g. Kronecker
• CPC Class Codes: H04J 13/004 Orthogonal
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04J 13/18 Allocation of orthogonal codes
• CPC Class Codes: H04L 1/0007 by modifying the frame length
• CPC Class Codes: H04L 1/165 Variable formats
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
• CPC Class Codes: H04L 27/2601 Multicarrier modulation systems
• CPC Class Codes: H04L 7/06 the synchronisation signals differing from the information signals in amplitude, polarity or frequency or length
• CPC Class Codes: H04Q 11/0428 Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals
• CPC Class Codes: H04Q 2213/13098 Mobile subscriber
• CPC Class Codes: H04Q 2213/13202 Network termination [NT]
• CPC Class Codes: H04Q 2213/13204 : Protocols
• CPC Class Codes: H04Q 2213/13209 : ISDN
• CPC Class Codes: H04Q 2213/13216 : Code signals, frame structure
• CPC Class Codes: H04Q 2213/1327 : Release and resetting of connection
• CPC Class Codes: H04Q 2213/13298 : Local loop systems, access network
• CPC Class Codes: H04Q 2213/13332 : Broadband, CATV, dynamic bandwidth allocation
• CPC Class Codes: H04Q 2213/1336 : Synchronisation
• CPC Class Codes: H04Q 2213/13389 : LAN, internet
• CPC Class Codes: H04W 24/00 : Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/20 : Negotiating bandwidth
• CPC Class Codes: H04W 28/22 : Negotiating communication rate
• CPC Class Codes: H04W 56/00 : Synchronisation arrangements
• CPC Class Codes: H04W 56/0045 : compensating for timing error by altering transmission time
• CPC Class Codes: H04W 56/0075 : based on arrival time vs. expected arrival time
• CPC Class Codes: H04W 72/044 : based on the type of the allocated resource
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/0466 : the resource being a scrambling code
• CPC Class Codes: H04W 72/21 : in the uplink direction of a wireless link, i.e. towards the network
• CPC Class Codes: H04W 74/00 : Wireless channel access
• CPC Class Codes: H04W 74/04 : Scheduled access hybrid access H04W74/02
• CPC Class Codes: H04W 76/28 : Discontinuous transmission [DTX]; Discontinuous reception [DRX]
• CPC Class Codes: H04W 84/14 : WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Abstract

A method for monitoring idling mode connections between a base station and idling subscriber units that are powered on, but not actively sending data, is provided. The method includes making available a plurality of orthogonal subchannels within at least one Code Division Multiple Access (CDMA) radio frequency (RF) channel. A shared orthogonal subchannel is assigned to at least two different idling subscriber units, but utilizing different time slots of the shared orthogonal subchannels. For each idling subscriber unit assigned the shared orthogonal subchannel, a respective heartbeat signal is sent within its assigned time slot at a data rate that is low enough to maintain bit synchronization with the base station. The respective heartbeat signals are tracked within the assigned time slots by selecting an assigned time slot within the shared orthogonal subchannel, retrieving a previous tracking of a respective heartbeat signal for an idling subscriber unit associated with the assigned time slot, determining a current tracking of the respective heartbeat signal for the idling subscriber unit associated with the assigned time slot, and updating the tracking of the idling subscriber unit associated with the assigned time slot based upon its current and previous trackings.

Claims

1. A method for monitoring on a reverse link idling mode connections between a base station and a plurality of idling subscriber units that are powered on, but not actively sending data, the method comprising:

making available a plurality of orthogonal subchannels within at least one Code Division Multiple Access (CDMA) radio frequency (RF) channel;

assigning a shared orthogonal subchannel to at least two different idling subscriber units, but utilizing different time slots of the shared orthogonal subchannels;

for each idling subscriber unit assigned the shared orthogonal subchannel, sending a respective heartbeat signal within its assigned time slot at a data rate that is low enough to maintain bit synchronization with the base station; and

tracking the respective heartbeat signals within the assigned time slots by

selecting an assigned time slot within the shared orthogonal subchannel,

retrieving a previous tracking of a respective heartbeat signal for an idling subscriber unit associated with the assigned time slot,

determining a current tracking of the respective heartbeat signal for the idling subscriber unit associated with the assigned time slot,

updating the tracking of the idling subscriber unit associated with the assigned time slot based upon its current and previous trackings,

storing the updated tracking for the idling subscriber unit associated with the assigned time slot, and

selecting a next assigned time slot within the shared orthogonal subchannel, and repeating the retrieving, determining, updating and storing for a different idling subscriber unit associated with the next selected assigned time slot.

2. A method according to claim 1 wherein for a first time tracking of the respective heartbeat signals within the assigned time slots, the previous tracking is a default tracking.

3. A method according to claim 1 wherein the base station assigns the shared orthogonal subchannel.

4. A method according to claim 1 wherein the different time slots of the shared orthogonal subchannel are uniquely assigned.

5. A method according to claim 4 wherein each idling subscriber unit sends the heartbeat signal in its uniquely assigned time slot.

6. A method according to claim 4 wherein an idling subscriber unit enters an active mode by sending a command signal to the base station using its uniquely assigned time slot to request allocation of additional available orthogonal subchannels.

7. A method according to claim 1 wherein the base station sends feedback to each idling subscriber unit relating to an adjustment of its transmit timing.

8. A method according to claim 1 wherein the base station sends feedback to each idling subscriber unit relating to an adjustment of its transmit power.

9. A method according to claim 1 wherein the base station comprises a code correlator for tracking the respective heartbeat signals within the assigned time slots of the shared orthogonal subchannel.

10. A method according to claim 1 wherein the base station comprises an early-late correlator for tracking the respective heartbeat signals within the assigned time slots of the shared orthogonal subchannel.

11. A method for monitoring idling mode connections between a base station and a plurality of idling subscriber units that are powered on, but not actively sending data, the method comprising:

making available a plurality of orthogonal subchannels within at least one Code Division Multiple Access (CDMA) radio frequency (RF) channel;

assigning a shared orthogonal subchannel to at least two different idling subscriber units, but utilizing different time slots of the shared orthogonal subchannels;

for each idling subscriber unit assigned the shared orthogonal subchannel, sending a respective heartbeat signal within its assigned time slot at a data rate that is low enough to maintain bit synchronization with the base station; and

tracking the respective heartbeat signals within the assigned time slots by

selecting an assigned time slot within the shared orthogonal subchannel,

retrieving a previous tracking of a respective heartbeat signal for an idling subscriber unit associated with the assigned time slot,

determining a current tracking of the respective heartbeat signal for the idling subscriber unit associated with the assigned time slot, and

updating the tracking of the idling subscriber unit associated with the assigned time slot based upon its current and previous trackings.

12. A method according to claim 11 wherein tracking the respective heartbeat signals further comprises storing the updated tracking for the idling subscriber unit associated with the assigned time slot.

13. A method according to claim 12 wherein tracking the respective heartbeat signals further comprises selecting a next assigned time slot within the shared orthogonal subchannel, and repeating the retrieving, determining, updating and storing for a different idling subscriber unit associated with the next selected assigned time slot.

14. A method according to claim 11 wherein for a first time tracking of the respective heartbeat signals within the assigned time slots, the previous tracking is a default tracking.

15. A method according to claim 11 wherein the base station assigns the shared orthogonal subchannel.

16. A method according to claim 11 wherein the different time slots of the shared orthogonal subchannel are uniquely assigned.

17. A method according to claim 16 wherein each idling subscriber unit sends the heartbeat signal in its uniquely assigned time slot.

18. A method according to claim 16 wherein an idling subscriber unit enters an active mode by sending a command signal to the base station using its uniquely assigned time slot to request allocation of additional available orthogonal subchannels.

19. A method according to claim 11 wherein the base station sends feedback to each idling subscriber unit relating to an adjustment of its transmit timing.

20. A method according to claim 11 wherein the base station sends feedback to each idling subscriber unit relating to an adjustment of its transmit power.

21. A method according to claim 11 wherein the base station comprises a code-correlator for tracking the respective heartbeat signals within the assigned time slots of the shared orthogonal subchannel.

22. A method according to claim 11 wherein the base station comprises an early-late correlator for tracking the respective heartbeat signals within the assigned time slots of the shared orthogonal subchannel.

23. A base station comprising:

a plurality of Code Division Multiple Access (CDMA) transceivers; and

a bandwidth management circuit connected to said plurality of CDMA transceivers for monitoring idling mode connections with a plurality of idling subscriber units that are powered on, but not actively sending data, said bandwidth management circuit

making available a plurality of orthogonal subchannels within at least one CDMA radio frequency (RF) channel,

assigning a shared orthogonal subchannel to at least two different idling subscriber units, but utilizing different time slots of the shared orthogonal subchannel,

receiving from each idling subscriber unit assigned the shared orthogonal subchannel, a respective heartbeat signal within its assigned time slot at a data rate that is low enough to maintain bit synchronization with the base station, and

tracking the respective heartbeat signals within the assigned time slots by

selecting an assigned time slot within the shared orthogonal subchannel,

retrieving a previous tracking of a respective heartbeat signal for an idling subscriber unit associated with the assigned time slot,

determining a current tracking of the respective heartbeat signal for the idling subscriber unit associated with the assigned time slot, and

updating the tracking of the idling subscriber unit associated with the assigned time slot based upon its current and previous trackings.

24. A base station according to claim 23 wherein tracking the respective heartbeat signals by said bandwidth management circuit further comprises storing the updated tracking for the idling subscriber unit associated with the assigned time slot.

25. A base station according to claim 24 wherein tracking the respective heartbeat signals by said bandwidth management circuit further comprises selecting a next assigned time slot within the shared orthogonal subchannel, and repeating the retrieving, determining, updating and storing for a different idling subscriber unit associated with the next selected assigned time slot.

26. A base station according to claim 23 wherein for a first time tracking of the respective heartbeat signals within the assigned time slots by said bandwidth management circuit, the previous tracking is a default tracking.

27. A base station according to claim 23 wherein the different time slots of the shared orthogonal subchannel are uniquely assigned.

28. A base station according to claim 27 wherein each idling subscriber unit sends the heartbeat signal in its uniquely assigned time slot.

29. A base station according to claim 23 wherein one of said plurality of CDMA transceivers sends feedback to each idling subscriber unit relating to an adjustment of its transmit timing.

30. A base station according to claim 23 wherein one of said plurality of CDMA transceivers sends feedback to each idling subscriber unit relating to an adjustment of its transmit power.

31. A base station according to claim 23 wherein said bandwidth management circuit comprises a code-correlator for tracking the respective heartbeat signals within the assigned time slots of the shared orthogonal subchannel.

32. A base station according to claim 23 wherein said bandwidth management circuit comprises an early-late correlator for tracking the respective heartbeat signals within the assigned time slots of the shared orthogonal subchannel.