IP Library Granted Patent US 7,542,448
Granted Patent B2
US 7,542,448 · App. 11/241,822 · Granted Jun 2, 2009

Providing handoff in a spread spectrum wireless communications system for high rate packet data

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Quick Facts
Patent No.
US 7,542,448
App. No.
11/241,822
Granted
Jun 2, 2009
Kind
B2
Abstract

The present invention provides a method and an apparatus for wireless communication between a wireless unit and a set of base stations. The method includes signaling the wireless unit about a plurality of transmissions of same packet data from the set of base stations to enable a soft handoff on a forward link. The plurality of transmissions of same packet data having an unsynchronized relationship. The wireless unit may use a detection/demodulation function, which is capable of simultaneously receiving and decoding signals from two or more sectors (base stations). Instead of soft-combining signals received from multiple cell sectors, the wireless unit independently decodes the received signals. Since soft combining of transmissions is avoided, there is no need to synchronize their transmissions of the same data to a particular wireless unit.

Claims (73)

1. A method of wireless communication between a wireless unit and a set of base stations, the method comprising:

signaling said wireless unit about a plurality of transmissions of a data packet from at least two base stations of said set of base stations to enable a handoff on a forward link, said plurality of transmissions of the data packet being unsynchronized;

enabling said wireless unit to select a desired packet from each of said plurality of transmissions of same packet data;

enabling said wireless unit to discard a duplicate packet across said plurality of transmissions of said same packet data; and

enabling said wireless unit to reorder a non-duplicate packet in each of said plurality of transmissions of said same packet data.

2. A method of claim 1 , wherein signaling said wireless unit further comprises:

enabling said wireless unit to receive asynchronously same packet in said plurality of transmission; and

enabling said wireless unit to decode said plurality of transmissions of said same packet data independently into a plurality of signals, each of said signals associated with a different sector of said set of base stations in a wireless spread-spectrum packet data system.

3. A method of claim 1 , wherein providing a signaling indication further comprises:

providing a signaling indication to said wireless unit to indicate that at least a first and a second base station of said set of base stations intend to transmit said same packet data to said wireless unit; and

using said signaling indication to establish a soft handoff on said forward link of a wireless spread-spectrum packet data system.

4. A method of claim 3 , further comprising:

signaling said wireless unit about a first and a second base stations of said set of base stations, each of said first and second base stations to independently schedule transmission of said same packet data for independently decoding a signal associated therewith in said soft handoff on said forward link.

5. A method of claim 4 , further comprising:

requesting transmission of said same packet data from at least two cell sectors associated with one or more of said set of base stations.

6. A method of claim 1 , further comprising

using a protocol that provides a reverse link soft handoff to establish a soft handoff on said forward link in a high rate packet data system based on a wireless spread-spectrum communication protocol.

7. A method of claim 1 , further comprising:

signaling one or more messages to a base station of said set of base stations for requesting a reduced active set of base stations as a subset of an active set associated with a reverse link to provide a soft handoff on said forward link for transmission of said same packet data.

8. A method of claim 1 , further comprising:

modifying a format of a data source channel to request switching to a multi-sector transmission mode.

9. A method of claim 1 , further comprising:

determining whether said wireless unit is in a handoff mode; and

if so, signaling from a radio network controller an indication to said wireless unit to indicate a set of at least two base station sectors associated with said set of base stations that intend to transmit same packet data to said wireless unit.

10. A method of wireless communication between a wireless unit and a base station, the method comprising:

signaling a request to said base station for transmission of a data packet from a plurality of base station sectors, said transmission of the data packet having an unsynchronized relationship across said plurality of base station sectors;

in response to said request, receiving a message indicating a set of at least two base station sectors that intend to transmit the data packet to said wireless unit;

establishing a handoff on a forward link for said set of at least two base station sectors;

receiving at said wireless unit a signal from each of said set of at least two base station sectors in an active set of base station sectors during a soft handoff for simultaneously decoding said each signal into a corresponding signal component,

selecting a desired packet from each of said corresponding signal component arriving from said set of at least two base station sectors;

discarding a duplicate packet across each of said signal associated with each of said set of at least two base station sectors; and

reordering a non-duplicate packet in each of said signal associated with each of said set of at least two base station sectors.

11. A method of claim 10 , further comprising:

receiving at said wireless unit a signal from each of said set of at least two base station sectors in an active set of base station sectors during a soft handoff for simultaneously decoding said each signal into a corresponding signal component.

12. A method of claim 10 , further comprising:

modifying a format of an acknowledgement channel to acknowledge reception of a same packet data from said active set of base station sectors in said soft handoff.

13. A method of claim 10 , further comprising:

causing a radio network controller to send a copy of a data stream to said active set of base station sectors participating in a soft handoff on said forward link.

14. A method of wireless communication between a base station and at least one wireless unit, the method comprising:

providing a message indicating a set of at least a first and a second base station sectors of a plurality of base station sectors that intend to transmit to said wireless unit;

scheduling a first and a second transmissions of same packet data having an unsynchronized relationship across said firsts and said second base station sectors for separately decoding at said wireless unit into a first a second signals, respectively:

establishing a handoff on a forward link,

enabling said wireless unit to select a desired packet from each of said first and second transmissions of said same packet data;

enabling said wireless unit to discard a duplicate packet across said first and second transmissions of said same packet data; and

enabling said wireless unit to reorder a non-duplicate packet in each of said first and second transmissions of said same packet data.

15. A method of wireless communication between a base station and a wireless unit, the method comprising:

providing a message indicating a set of at least a first and a second base station sectors of a plurality of base station sectors that intend to transmit to said wireless unit;

scheduling a first and a second transmissions of same packet data having an unsynchronized relationship across said first and said second base station sectors for separately decoding at said wireless unit into a first and a second signals, respectively;

establishing a soft handoff on a forward link;

modifying a format of a data rate request channel to enable said set of at least said first and said second base station sectors to independently schedule said first and second transmissions of said same packet data to said wireless unit without synchronizing transmission of said same packet data.

16. A method of claim 15 , further comprising:

modifying a format of the data rate request channel and an acknowledgement channel to provide a per handoff leg data rate request and acknowledgement channels to use a per handoff leg signaling that is used per carrier in a multi-carrier transmission mode; and

enabling a multi-sector transmission mode for said forward link on the same carrier of said multi-carrier transmission mode.

17. A method of claim 16 , further comprising:

transmitting said acknowledgement channel and a data rate request channel to one base station sector only;

receiving said data rate request channel on said plurality of base station sectors; and

ignoring said acknowledgement channel on said plurality of base station sectors except the said one base station sector at which the said acknowledgement channel has been transmitted to enable a multi-carrier transmission mode for said forward link to said one base station sector.

18. A method of claim 15 , further comprising:

measuring a signal strength of each pilot of each base station sector of said plurality of base station sectors; and

in response to a majority of pilots indicate said signal strength to be below a weak signal threshold, switching from a multi-carrier transmission mode from a signle base station sector to a multi-sector transmission mode on the same carrier of said multi-carrier transmission mode.

19. A method of claim 15 , further comprising:

measuring a signal strength of each pilot of each base station sector of said plurality of base station sectors; and

in response to at least one pilot indicates said signal strength to be above a strong signal threshold, switching from a multi-sector transmission mode on the same carrier of said multi-carrier transmission mode to a multi-carrier transmission mode from a signle base station sector.

20. A method of claim 15 , further comprising:

enabling said wireless unit to request a downlink data rate from said set of at least said first and second base station sectors participating in said soft handoff on said forward link.

21. A method of claim 15 further comprising:

enabling said set of at least said first and second base station sectors to receive and operate upon a data rate request channel independent of a unique code cover used from a serving base station sector on said data rate request channel.

22. A method of claim 15 further comprising:

using a receiver at said wireless unit for independently decoding said first and second transmissions of said same packet data associated with a multi-carrier transmission mode from a single base station sector.

23. A method of claim 15 , further comprising:

transmitting said data rate request channel to one base station sector only;

receiving said data rate request channel on said plurality of base station sectors; and

disabling said acknowledgment channel in a multi-sector transmission mode to enable the multi-sector transmission mode for said forward link.

Assignments (10)
RELEASE OF SECURITY INTEREST Recorded May 21, 2019
From: BANK OF AMERICA, N.A.
To: LGS INNOVATIONS LLC
Reel/Frame 049247/0557 →
RELEASE OF SECURITY INTEREST Recorded May 2, 2019
From: BANK OF AMERICA, N.A.
To: LGS INNOVATIONS LLC
Reel/Frame 049074/0094 →
NOTICE OF GRANT OF SECURITY INTEREST IN PATENTS Recorded Jul 19, 2017
From: LGS INNOVATIONS LLC
To: BANK OF AMERICA, N.A.
Reel/Frame 043254/0393 →
RELEASE OF SECURITY INTEREST Recorded Oct 9, 2014
From: CREDIT SUISSE AG
To: ALCATEL-LUCENT USA INC.
Reel/Frame 033949/0531 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Apr 23, 2014
From: ALCATEL LUCENT
To: LGS INNOVATIONS LLC
Reel/Frame 032743/0584 →
SECURITY INTEREST Recorded Apr 1, 2014
From: LGS INNOVATIONS LLC
To: BANK OF AMERICA NA
Reel/Frame 032579/0066 →
RELEASE OF SECURITY INTEREST Recorded Apr 1, 2014
From: CREDIT SUISSE AG
To: ALCATEL-LUCENT USA INC.
Reel/Frame 032578/0931 →
SECURITY INTEREST Recorded Mar 7, 2013
From: ALCATEL-LUCENT USA INC.
To: CREDIT SUISSE AG
Reel/Frame 030510/0627 →
MERGER Recorded Apr 1, 2009
From: LUCENT TECHNOLOGIES INC.
To: ALCATEL-LUCENT USA INC.
Reel/Frame 022480/0576 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 10, 2005
From: QI, BI; VITEBSKY, STANLEY; YANG, YANG
To: LUCENT TECHNOLOGIES INC.
Reel/Frame 017313/0490 →