Method and system for predictive handoff of a data session between entities

• US 7,408,901 B1
• Filed: 12/29/2004
• Issued: 08/05/2008
• Est. Priority Date: 12/29/2004
• Status: Active Grant

• Current Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Original Assignee: Sprint Spectrum LP (Deutsche Telekom AG)
• Inventors: Narayanabhatla, Shiva
• Primary Examiner(s): Corsaro; Nick
• Assistant Examiner(s): Mack; Sylvia
• Application Number:
  US11/025,416
• Time in Patent Office: 1,315 Days
• Field of Search: 455/438, 455/439, 455/440, 455/441, 455/436, 370/328, 370/331
• US Class Current: 370/331
• CPC Class Codes: H04W 36/10 Reselecting an access point controller
• CPC Class Codes: H04W 92/22 between access point controllers

Abstract

A method and system for managing handoff of a cellular wireless data session between a first wireless coverage area and second wireless coverage area. A first radio network controller (RNC) predicts that handoff of the data session will soon be necessary. Radio resources for continuing the data session in the second wireless coverage area are reserved. The reserved radio resources may be controlled by the first RNC or by a second RNC. The first RNC sends, to a wireless communication device, a predictive handoff directive message that instructs the wireless communication device (i) to wait a designated period of time, and (ii) to then handoff the data session.

Claims

1. A system comprising:

a source radio network controller (RNC);

a target RNC communicatively coupled with the source RNC;

a wireless communication device operable to establish a data session via the source RNC;

a first base transceiver station (BTS) communicatively coupled to the source RNC, wherein the first BTS provides a source pilot signal;

a second BTS communicatively coupled to the target RNC, wherein the second BTS provides a target pilot signal;

a processor at the wireless communication device; and

data storage, at the wireless communication device, that includes a predictive threshold and program instructions executable by the processor,

wherein the wireless communication device is arranged to receive the source and target pilot signals,

wherein the program instructions include instructions for (i) comparing a strength of the target pilot signal received at the wireless communication device to a strength of the source pilot signal received at the wireless communication device, and (ii) making a determination that the strength of the target pilot signal received at the wireless communication device exceeds the strength of the source pilot signal received at the wireless communication device by at least the predictive threshold,

wherein the wireless communication device notifies the source RNC of the determination,

wherein the source RNC makes a prediction that handoff of the data session to the target RNC will soon be necessary, and the source RNC responsively (i) sends a signal to the target RNC to cause the target RNC to reserve radio resources for the data session, and (ii) sends a predictive handoff directive message to the wireless communication device,

wherein the predictive handoff directive message instructs the wireless communication device (i) to wait a designated period of time, and (ii) to then handoff, and

wherein the source RNC makes the prediction based at least in part on the determination.

3. The system of claim 1, further comprising:

a first communication interface at the source RNC; and

a second communication interface at the target RNC,

wherein the signal comprises an Internet-Protocol (IP) based signal communicated from the first communication interface to the second communication interface, wherein the IP based signal includes information sufficient to allow the target RNC to reserve the radio resources for the data session.

4. The system of claim 3, wherein the IP based signal includes an IP address currently assigned to the wireless communication device.

5. The system of claim 1, wherein the radio resources include a traffic channel for carrying the data session.

6. The system of claim 1, wherein the radio resources include a time division multiplex (TDM) timeslot for carrying the data session.

2. A system comprising:

a source radio network controller (RNC);

a target RNC communicatively coupled with the source RNC;

a wireless communication device operable to establish a data session via the source RNC;

a first base transceiver station (BTS) communicatively coupled to the source RNC, wherein the first BTS provides a source pilot signal;

a second BTS communicatively coupled to the target RNC, wherein the second BTS provides a target pilot signal;

a processor at the source RNC; and

data storage at the source RNC, wherein the data storage includes a predictive threshold and program instructions executable by the processor,

wherein the wireless communication device is arranged to receive the source and target pilot signals and provide to the RNC an indication of (i) a strength of the source pilot signal received by the wireless communication device, and (ii) a strength of the target pilot signal received by the wireless communication device,

wherein the program instructions include instructions for (i) comparing a strength of the target pilot signal received at the wireless communication device to a strength of the source pilot signal received at the wireless communication device, and (ii) making a determination that the strength of the target pilot signal received at the wireless communication device exceeds the strength of the source pilot signal received at the wireless communication device by at least the predictive threshold,

wherein the source RNC makes a prediction that handoff of the data session to the target RNC will soon be necessary, and the source RNC responsively (i) sends a signal to the target RNC to cause the target RNC to reserve radio resources for the data session, and (ii) sends a predictive handoff directive message to the wireless communication device,

wherein the predictive handoff directive message instructs the wireless communication device (i) to wait a designated period of time, and (ii) to then handoff, and

wherein the source RNC makes the prediction based at least in part on the determination.

9. The system of claim 2, further comprising:

a first communication interface at the source RNC; and

a second communication interface at the target RNC,

wherein the signal comprises an Internet-Protocol (IP) based signal communicated from the first communication interface to the second communication interface, wherein the IP based signal includes information sufficient to allow the target RNC to reserve the radio resources for the data session.

10. The system of claim 2, wherein the IP based signal includes an IP address currently assigned to the wireless communication device.

11. The system of claim 2, wherein the radio resources include a traffic channel for carrying the data session.

12. The system of claim 2, wherein the radio resources include a time division multiplex (TDM) timeslot for carrying the data session.

7. A system comprising:

a base station system defining a first wireless coverage area and a second wireless coverage area;

a wireless communication device operable to communicate wirelessly with the base station system while in the first wireless coverage area and while in the second wireless coverage area;

an RNC controlling the base station system and providing connectivity between the base station system and a packet switched network, wherein the wireless communication device is operable to engage in packet data session via the base station system and the RNC;

a processor at the wireless communication device; and

data storage, at the wireless communication device, that includes a predictive threshold and program instructions executable by the processor,

wherein the base station system provides a source pilot signal for the first wireless coverage area and a target pilot signal for the second wireless coverage area,

wherein the wireless communication device is arranged to receive the source and target pilot signals,

wherein the program instructions include instructions for (i) comparing a strength of the target pilot signal received at the wireless communication device to a strength of the source pilot signal received at the wireless communication device, and (ii) making a determination whether the strength of the target pilot signal received at the wireless communication device exceeds the strength of the source pilot signal received at the wireless communication device by at least the predictive threshold,

wherein the wireless communication device notifies the RNC of the determination,

wherein the RNC is operable to predict that a handoff of the data session from the first wireless coverage area to the second wireless coverage area will soon be necessary, and to responsively (i) reserve target radio resources to carry the data session in the second wireless coverage area and (ii) send to the wireless communication device a predictive handoff directive message that instructs the wireless communication device to wait a designated period of time and to then handoff to the second wireless coverage area, and

wherein the RNC predicts that handoff will soon be necessary based at least in part on the determination.

8. A system comprising:

a base station system defining a first wireless coverage area and a second wireless coverage area;

a wireless communication device operable to communicate wirelessly with the base station system while in the first wireless coverage area and while in the second wireless coverage area;

an RNC controlling the base station system and providing connectivity between the base station system and a packet switched network, wherein the wireless communication device is operable to engage in packet data session via the base station system and the RNC;

a processor at the RNC; and

data storage, at the RNC, that includes a predictive threshold and program instructions executable by the processor,

wherein the base station system provides (i) a source pilot signal for the first wireless coverage area, and (ii) a target pilot signal for the second wireless coverage area,

wherein the wireless communication device is arranged to receive the source and target pilot signals and provide to the RNC an indication of (i) a strength of the source pilot signal received by the wireless communication device, and (ii) a strength of the target pilot signal received by the wireless communication device,

wherein the program instructions include instructions for (i) comparing the strength of the target pilot signal received by the wireless communication device to the strength of the source pilot signal received by the wireless communication device, and (ii) making a determination whether the strength of the target pilot signal received by the wireless communication device exceeds the strength of the source pilot signal received by the wireless communication device by at least the predictive threshold,

wherein the RNC is operable to predict that a handoff of the data session from the first wireless coverage area to the second wireless coverage area will soon be necessary, and to responsively (i) reserve target radio resources to carry the data session in the second wireless coverage area and (ii) send to the wireless communication device a predictive handoff directive message that instructs the wireless communication device to wait a designated period of time and to then handoff to the second wireless coverage area, and

wherein the RNC predicts that handoff will soon be necessary based at least in part on the determination.