Call continuity in high uplink interference state

Patent metadata

Field	Value
Publication number	US-10009401-B2
Application number	US-201514863416-A
Country	US
Kind code	B2
Filing date	Sep 23, 2015
Priority date	Sep 23, 2015
Publication date	Jun 26, 2018
Grant date	Jun 26, 2018

Abstract

A method, an apparatus, and a computer program product for wireless communication are provided. The apparatus receives a stream of RTP data packets over a wireless channel and applies ROHC decompression to decode the packets. Upon a failure of ROHC decompression, the apparatus identifies the RTP sequence number (SN), RTP Timestamp (TS), and PDCP receive time (RT) of a prior successfully decoded packet, and the PDCP SN and PDCP RT of the failed packets. Using the identified information, the apparatus estimates the RTP SN and RTP TS of each of the failed packets. The apparatus decodes the packets using the estimated information.

First claim

What is claimed is:

1. A method of wireless communication, comprising:
receiving a plurality of Real-time Transport (RTP) packets over a wireless channel, each of the plurality of RTP packets including at least one RTP parameter and at least one Packet Data Convergence Protocol (PDCP) parameter;
applying Robust Header Compression (ROHC) decompression to decode the received RTP packets wherein a decoding failure occurs for at least one of the packets;
estimating at least one RTP parameter of the failed at least one packet based on a corresponding PDCP parameter of the at least one PDCP parameter; and
decoding the failed at least one packet using the at least one estimated RTP parameter.

2. The method of claim 1 , wherein the at least one estimated RTP parameter comprises an RTP sequence number (SN) and an RTP timestamp.

3. The method of claim 2 , wherein the corresponding PDCP parameter comprises a PDCP SN and a PDCP receive time.

4. The method of claim 1 , wherein estimating the at least one RTP parameter comprises estimating an RTP sequence number (SN) of the failed at least one packet based upon a difference between a PDCP SN of the failed at least one packet and a PDCP SN of a prior successfully decoded packet.

5. The method of claim 4 , wherein the estimated RTP SN of the failed at least one packet is calculated based on the following equation:
SN RTP,est =SN RTP,sd +(SN PDCP,f −SN PDCP,sd )

where
SN PDCP,f =PDCP SN of the failed at least one packet;
SN PDCP,sd =PDCP SN of the prior successfully decoded packet; and
SN RTP,sd =RTP SN of the prior successfully decoded packet.

6. The method of claim 4 , wherein estimating the at least one RTP parameter further comprises estimating an RTP timestamp of the failed at least one packet based upon a difference between a PDCP receive time of the failed at least one packet and a PDCP receive time of the prior successfully decoded packet to generate an estimated RTP timestamp.

7. The method of claim 4 , wherein estimating the at least one RTP parameter further comprises estimating an RTP timestamp of the failed at least one packet based upon a difference between the estimated RTP SN of the failed at least one packet and an RTP SN of the prior successfully decoded packet.

8. The method of claim 6 , wherein the estimated RTP timestamp of the failed at least one packet is calculated based on the following equation:
TS RTP,est =TS RTP,sd +{floor((RT PDCP,f −RT PCDP,sd )/20)× n}

wherein
RT PDCP,f =PDCP receive time of the failed packet;
RT PDCP,sd =PDCP receive time of the prior successfully decoded packet;
TS RTP,sd =RTP timestamp of the prior successfully decoded packet; and
n is a conversion factor.

9. The method of claim 7 , wherein the estimated RTP timestamp of the failed at least one packet is calculated based on the following equation:
TS RTP,est =TS RTP,sd +(SN RTP,est −SN RTP,sd )× t c

where
TS RTP,sd =RTP timestamp of the prior successfully decoded packet;
SN RTP,est =the estimated RTP SN of the failed packet;
SN RTP,sd =the RTP SN of the prior successfully decoded packet; and
t c =a conversion measure in time.

10. The method of claim 4 , wherein the RTP packets comprise Voice over Long Term Evolution (VoLTE) packets and estimating the at least one RTP parameter further comprises:
estimating an RTP timestamp of the failed at least one packet based upon a difference between the estimated RTP SN of the failed at least one packet and an RTP SN of the prior successfully decoded packet, when the failed at least one packet and the prior successfully decoded packet are part of the same talk spurt; and
estimating an RTP timestamp of the failed at least one packet based upon a difference between a PDCP receive time of the failed at least one packet and a PDCP receive time of the prior successfully decoded packet, when the failed at least one packet and the prior successfully decoded packet are not part of the same talk spurt.

11. The method of claim 6 , wherein decoding the failed at least one packet using the at least one RTP parameter comprises:
applying ROHC to decode the failed at least one packet using the estimated at least RTP parameter;
experiencing another decoding failure for the failed at least one packet;
modifying the estimated RTP timestamp by a predetermined value to generate a modified estimated RTP timestamp; and
decoding the failed at least one packet using the modified estimated RTP timestamp.

12. The method of claim 11 , wherein decoding the failed at least one packet using the modified estimated RTP timestamp further comprises successively modifying the estimated RTP timestamp in predetermined increments until the failed at least one packet is successfully decoded or a threshold is reached.

13. The method of claim 12 , wherein the threshold comprises at least one of an elapsed time and a number of attempts.

14. The method of claim 1 , wherein the RTP packets comprise Voice over Long Term Evolution (VoLTE) packets.

15. An apparatus for wireless communication, comprising:
means for receiving a plurality of Real-time Transport (RTP) packets on a wireless channel, each of the plurality of RTP packets including at least one RTP parameter and at least one Packet Data Convergence Protocol (PDCP) parameter;
means for applying Robust Header Compression (ROHC) decompression to decode the received RTP packets wherein a decoding failure occurs for at least one of the packets;
means for estimating at least one RTP parameter of the failed at least one packet based on a corresponding PDCP parameter of the at least one PDCP parameter; and
means for decoding the failed at least one packet using the at least one estimated RTP parameter.

16. The apparatus of claim 15 , wherein the at least one estimated RTP parameter comprises an RTP sequence number (SN) and an RTP timestamp.

17. The apparatus of claim 16 , wherein the corresponding PDCP parameter comprises a PDCP SN and a PDCP receive time.

18. The apparatus of claim 15 , wherein the means for estimating the at least one RTP parameter comprises means for estimating an RTP sequence number (SN) of the failed at least one packet based upon a difference between a PDCP SN of the failed at least one packet and a PDCP SN of a prior successfully decoded packet.

19. The apparatus of claim 18 , wherein the estimated RTP SN of the failed at least one packet is calculated based on the following equation:
SN RTP,est =SN RTP,sd +(SN PDCP,f −SN PDCP,sd )

where
SN PDCP,f =PDCP SN of the failed at least one packet;
SN PDCP,sd =PDCP SN of the prior successfully decoded packet; and
SN RTP,sd =RTP SN of the prior successfully decoded packet.

20. The apparatus of claim 18 , wherein the means for estimating the at least one RTP parameter further comprises means for estimating an RTP timestamp of the failed at least one packet based upon a difference between a PDCP receive time of the failed at least one packet and a PDCP receive time of the prior successfully decoded packet to generate an estimated RTP timestamp.

21. The apparatus of claim 18 , wherein the means for estimating the at least one RTP parameter further comprises means for estimating an RTP timestamp of the failed at least one packet based upon a difference between the estimated RTP SN of the failed at least one packet and an RTP SN of the prior successfully decoded packet.

22. The apparatus of claim 20 , wherein the estimated RTP timestamp of the failed at least one pack

Assignees

• Qualcomm Inc

Inventors

• Agrawal Ambuj
• Ehsan Navid
• Sivakumar Nagamanikandan
• Bathwal Saket
• Al Khairy Mohammed

Classifications

• H04L69/22

  Parsing or analysis of headers · CPC title

• H04L65/1016 Primary

  IP multimedia subsystem [IMS] · CPC title

• H04L69/04

  Protocols for data compression, e.g. ROHC · CPC title

• H04L65/608

  Electricity · mapped topic

• H04L65/604 Primary

  Electricity · mapped topic