Forward link handoff for wireless communication systems with OFDM forward link and CDMA reverse link

• US 20050083888A1
• Filed: 12/22/2003
• Published: 04/21/2005
• Est. Priority Date: 01/07/2003
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Walton, Jay Rodney, Malladi, Durga P., Willenegger, Serge, Smee, John E.
• Granted Patent: US 8,400,979 B2
• Time in Patent Office: Days
• US Class Current: 370/332
• CPC Class Codes: H04W 36/0069 in case of dual connectivity, e.g. decoupled uplink/downlink
• CPC Class Codes: H04W 36/08 Reselecting an access point
• CPC Class Codes: H04W 36/144 over a different radio air interface technology
• CPC Class Codes: H04W 36/30 by measured or perceived connection quality data

Abstract

A method and apparatus for performing handoff in a wireless communication system with multi-carrier modulation (MCM) for a forward link and CDMA for a reverse link. In one embodiment, a method of performing handoff on the forward link for a terminal is provided in which signal quality of pilots received by the terminal from a plurality of base stations in the system is determined. A particular base station for subsequent data transmission on the forward link to the terminal is selected based on the signal quality determined for the plurality of base stations. A request to be handed off to the particular base station is initiated if the particular base station is different than a currently selected base station.

Claims

1. In a wireless communication system with multi-carrier modulation (MCM) for a forward link and CDMA for a reverse link, a method of performing handoff on the forward link for a terminal, comprising:

determining signal quality of pilots received by the terminal from a plurality of base stations in the system;

selecting a particular base station for subsequent data transmission on the forward link to the terminal based on the signal quality determined for the plurality of base stations; and

initiating a request to be handed off to the particular base station if different than a currently selected base station.

2. The method of claim 1, wherein the multi-carrier modulation is orthogonal frequency division multiplexing (OFDM).

3. The method of claim 1, wherein the signal quality relates to pilot power.

4. The method of claim 1, wherein the signal quality relates to signal-to-noise ratio (SNR).

5. The method of claim 1, wherein the selecting is further based on at least one additional criterion.

6. The method of claim 5, wherein the at least one additional criterion relates to loading on the forward link for base stations in the system.

7. The method of claim 1, wherein the selecting is performed using hysteresis to prevent ping-ponging between two base stations.

8. In a wireless communication system with multi-carrier modulation (MCM) for a forward link and CDMA for a reverse link, a method of performing handoff on the forward link for a terminal, comprising:

determining quality of a signal received from the terminal by a plurality of base stations in the system;

selecting a particular base station for subsequent data transmission on the forward link to the terminal based on the signal quality determined by the plurality of base stations; and

initiating a handoff of the terminal to the particular base station.

9. The method of claim 8, wherein the multi-carrier modulation is orthogonal frequency division multiplexing (OFDM).

10. The method of claim 8, wherein the signal quality relates to pilot power.

11. The method of claim 8, wherein the selecting is further based on at least one additional criterion.

12. The method of claim 11, wherein the at least one additional criterion relates to loading on the forward link for base stations in the system.

13. The method of claim 11, wherein the at least one additional criterion relates to measurements for the signal received from the terminal by the plurality of base stations.

14. A terminal in a wireless communication system with multi-carrier modulation (MCM) for a forward link and CDMA for a reverse link, comprising:

means for determining signal quality of pilots received by the terminal from a plurality of base stations in the system;

means for selecting a particular base station for subsequent data transmission on the forward link to the terminal based on the signal quality determined for the plurality of base stations; and

means for initiating a request to be handed off to the particular base station if different than a currently selected base station.

15. An apparatus in a wireless communication system with multi-carrier modulation (MCM) for a forward link and CDMA for a reverse link, comprising:

means for determining quality of a signal received from the terminal by a plurality of base stations in the system;

means for selecting a particular base station for subsequent data transmission on the forward link to the terminal based on the signal quality determined by the plurality of base stations; and

means for initiating a handoff of the terminal to the particular base station.