Method and apparatus for time-warping packets at the sender side

• US 8,274,945 B2
• Filed: 10/16/2006
• Issued: 09/25/2012
• Est. Priority Date: 10/16/2006
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Jayaram, Ranjith, Nanda, Sanjiv, Deshpande, Manoj, Meylan, Arnaud
• Primary Examiner(s): Appiah, Charles
• Assistant Examiner(s): COSME, NATASHA W
• Application Number:
  US11/549,931
• Publication Number:
  US 20080089289A1
• Time in Patent Office: 2,171 Days
• Field of Search: 370/331, 455/442
• US Class Current: 370/331
• CPC Class Codes: H04L 47/25 with rate being modified by the source upon detecting a change of network conditions
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off
• CPC Class Codes: H04W 36/1446 wherein at least one of the networks is unlicensed
• CPC Class Codes: H04W 88/06 adapted for operation in multiple networks or having at least two operational modes, e.g. multi-mode terminals

Abstract

The disclosure is directed to a mobile communication device that is capable of accessing different types of networks such as a circuit-switched network, or any cellular network, and a packet-switched network. During hand-over from the first network to the second network, the sender of packets/frames expands or compresses the packet-switched packets using well-known time-warping techniques. At the receiver end, the received time-warped packets and frames from the second network are appropriately selected so that no unwanted artifacts are introduced during playback.

Claims

1. A method used by a mobile communications device capable of communicating over multiple access networks, comprising:

transmitting normal packets created from a stream of speech samples over a first network;

identifying a first speech sample of one normal packet that will correspond in time to a first packet to be transmitted to a second network;

choosing a certain number of consecutive speech samples beginning with the first speech sample;

expanding, at a transmitter, the chosen number of speech samples in the normal packet to produce a first expanded packet;

generating from these samples the first expanded packet for transmitting over the first network; and

transmitting expanded packets on the first network for a time period that is based on a differential communications path delay of the first network and the second network.

2. The method of claim 1, further comprising:

for the time period, expanding consecutive speech samples subsequent to a last sample used for generating the first expanded packet; and

generating from these samples a number of expanded packets for transmitting over the first network.

3. The method of claim 1, wherein the first network comprises a packet-switched network.

4. The method of claim 3, wherein the packet-switched network includes a wireless LAN.

5. The method of claim 1, wherein the second network comprises a cellular network.

6. The method of claim 5, wherein the cellular network includes a packet-switched network.

7. A mobile communications device capable of communicating over multiple access networks, comprising:

a first transmitter configured to transmit normal packets and expanded packets over a first network; and

a processor configured to

identify one of the normal packets to be transmitted over the first network that corresponds in time to a first packet to be transmitted over a second network,

time-expand, at the transmitter, the identified normal packet to generate an expanded packet before passing the expanded packet to the first transmitter; and

transmit expanded packets on the first network for a time period that is based on a differential communications path delay of the first network and the second network.

8. The mobile communications device of claim 7, further comprising:

a second transmitter configured to transmit other packets over the second network.

9. The mobile communications device of claim 7, wherein the processor is further configured to time-expand each of the normal packets occurring in a time-period subsequent to the identified normal packet to generate respective expanded packets to be transmitted using the first transmitter.

10. The mobile communications device of claim 7, wherein the first network comprises a packet-switched network.

11. The mobile communications device of claim 10, wherein the packet-switched network includes a wireless LAN.

12. The mobile communications device of claim 7, wherein the second network comprises a cellular network.

13. The mobile communications device of claim 12, wherein the cellular network includes a packet-switched network.

14. A non-transitory computer readable media containing programming instructions for transmitting in a mobile communications device capable of communicating over multiple access networks, that upon execution thereof, causes one or more processors of the mobile device to perform the steps of:

transmitting normal packets created from a stream of speech samples over a first network;

identifying a first speech sample of one normal packet that will correspond in time to a first packet to be transmitted to a second network;

choosing a certain number of consecutive speech samples beginning with the first speech sample;

expanding, at a transmitter, the chosen number of speech samples in the normal packet to produce a first expanded packet;

generating from these samples a first expanded packet for transmitting over the first network; and

transmitting expanded packets on the first network for a time period that is based on a differential communications path delay of the first network and the second network.

15. A mobile communications device capable of communicating over multiple access networks, comprising:

a first transmitter configured to transmit normal packets and expanded packets over a first network;

means for identifying one of the normal packets to be transmitted over the first network that corresponds in time to a first packet to be transmitted over a second network;

means for time-expanding, at the first transmitter, the identified ene normal packet to generate an expanded packet before passing the expanded packet to the first transmitter; and

means for transmitting expanded packets on the first network for a time period that is based on a differential communications path delay of the first network and the second network.

16. A mobile communications device capable of communicating over multiple access networks, comprising:

means for transmitting normal packets created from a stream of speech samples over a first network;

means for identifying a first speech sample of one normal packet that will correspond in time to a first packet to be transmitted to a second network;

means for choosing a certain number of consecutive speech samples beginning with the first speech sample;

means for expanding, at a transmitter, the chosen number of speech samples in the normal packet to produce a first expanded packet;

means for generating from these samples the first expanded packet for transmitting over the first network; and

means for transmitting expanded packets on the first network for a time period that is based on a differential communications path delay of the first network and the second network.

17. The mobile communications device of claim 16, further comprising:

means for expanding, for the time period, consecutive speech samples subsequent to a last sample used for generating the first expanded packet; and

means for generating from these samples a number of expanded packets for transmitting over the first network.

18. The mobile communications device of claim 16, wherein the first network comprises a packet-switched network.

19. The mobile communications device of claim 18, wherein the packet-switched network includes a wireless LAN.

20. The mobile communications device of claim 16, wherein the second network comprises a cellular network.

21. The mobile communications device of claim 20, wherein the cellular network includes a packet-switched network.