Apparatus and method for signaling ran-assisted codec adaptation capabilities in IMS multimedia telephony sessions

1. An apparatus for a user equipment (UE) operable to stream media of a multimedia telephony session with a remote UE, the apparatus comprising:

a radio frequency (RF) interface configured to receive a session description protocol (SDP) offer message from the remote UE, wherein the SDP offer message includes a first SDP attribute parameter indicating support of access network bitrate recommendation (ANBR) capability of the remote UE, and wherein the ANBR capability of the remote UE corresponds to an ability of the remote UE to receive ANBR information from a remote radio access network (RAN) to which the remote UE is connected or an ability of the remote RAN to transmit the ANBR information; and

processor circuitry coupled with the RF interface, wherein the processor circuitry is configured to:

decode the SDP offer message received from the RF interface to obtain the first SDP attribute parameter;

determine, using the first SDP attribute parameter, the support of ANBR capability of the remote UE;

encode an SDP answer message in response to the SDP offer message,

wherein the SDP answer message includes a second SDP attribute parameter indicating support of ANBR capability of the UE, and wherein the ANBR capability of the UE corresponds to an ability of the UE to receive ANBR information from a RAN to which the UE is connected or an ability of the RAN to transmit the ANBR information;

cause transmission of the SDP answer message to the remote UE;

encode a real-time transport control protocol (RTCP) temporary maximum media stream bitrate request (TMMBR) message for transmission to the remote UE based on downlink ANBR information received from the RAN, wherein the RTCP TMMBR message is distinct from the SDP answer message and indicates a desired receiving bitrate for reception of video of the multimedia telephony session; and

cause transmission of the RTCP TMMBR message to the remote UE.

2. The apparatus of claim 1 , wherein both of the first SDP attribute parameter and the second SDP attribute parameter are identified as “ANBR_adapt”.

3. The apparatus of claim 1 , wherein the second SDP attribute parameter is further to indicate support of RAN-assisted codec adaptation of the UE, and the first SDP attribute parameter is further to indicate support of RAN-assisted codec adaptation of the remote UE.

4. The apparatus of claim 3 , wherein the RAN-assisted codec adaptation of the UE is performed by the UE based on the ANBR information received by the UE from the RAN, and the RAN-assisted codec adaptation of the remote UE is performed by the remote UE based on the ANBR information received by the remote UE from the remote RAN.

5. The apparatus of claim 4 , wherein the ANBR information received by the UE from the RAN is uplink ANBR information, and wherein the processor circuitry is to adjust a sending bitrate for transmission of the media of the multimedia telephony session based on the uplink ANBR information.

6. The apparatus of claim 5 , wherein the sending bitrate is decreased to a bitrate value indicated by the uplink ANBR information when the bitrate value is smaller than the sending bitrate.

7. The apparatus of claim 5 , wherein the sending bitrate is increased to the smallest one among a bitrate value indicated by the uplink ANBR information and a bitrate value restricted by each of other bitrate adaptation triggers for the UE, when the bitrate value indicated by the uplink ANBR information is greater than the sending bitrate.

8. The apparatus of claim 7 , wherein the ANBR information received by the remote UE from the remote RAN is downlink ANBR information, and wherein the processor circuitry is to adjust the sending bitrate further based on the downlink ANBR information for the remote UE when the bitrate value is greater than the sending bitrate.

9. One or more non-transitory computer-readable media having instructions stored thereon, the instructions when executed by processor circuitry of a user equipment (UE) cause the processor circuitry to:

decode a session description protocol (SDP) offer message received from a remote UE with which the UE is operable to stream media of a multimedia telephony session, wherein the SDP offer message includes a first SDP attribute parameter indicating support of access network bitrate recommendation (ANBR) capability of the remote UE, wherein the ANBR capability of the remote UE corresponds to an ability of the remote UE to receive ANBR information from a remote RAN to which the remote UE is connected;

encode an SDP answer message in response to the SDP offer message, wherein the SDP answer message includes a second SDP attribute parameter indicating support of ANBR capability of the UE, wherein the ANBR capability of the UE corresponds to an ability of the UE to receive ANBR information from a RAN to which the UE is connected;

cause transmission of the SDP answer message to the remote UE;

encode a real-time transport control protocol (RTCP) temporary maximum media stream bitrate request (TMMBR) message for transmission to the remote UE based on downlink ANBR information received from the RAN, wherein the RTCP TMMBR message is distinct from the SDP answer message and indicates a desired receiving bitrate for reception of video of the multimedia telephony session; and

cause transmission of the RTCP TMMBR message to the remote UE.

10. The one or more non-transitory computer-readable media of claim 9 , wherein the second SDP attribute parameter is further to indicate support of RAN-assisted codec adaptation of the UE, and the first SDP attribute parameter is further to indicate support of RAN-assisted codec adaptation of the remote UE, and

wherein the RAN-assisted codec adaptation of the UE is performed by the UE based on the ANBR information received by the UE from the RAN, and the RAN-assisted codec adaptation of the remote UE is performed by the remote UE based on the ANBR information received by the remote UE from the remote RAN.

11. The one or more non-transitory computer-readable media of claim 10 , wherein the ANBR information received by the UE from the RAN is downlink ANBR information, the media includes speech, and wherein the one or more computer-readable media further include instructions that, when executed, cause the processor circuitry to:

encode a codec mode request (CMR)/real-time transport control protocol (RTCP)-application (RTCP-APP) message for transmission to the remote UE based on the downlink ANBR information received from the RAN,

wherein the CMR/RTCP-APP message is to indicate a desired receiving bitrate for reception of the speech of the multimedia telephony session.

12. The one or more non-transitory computer-readable media of claim 11 , wherein the desired receiving bitrate is determined to be a bitrate value indicated by the downlink ANBR information, when the bitrate value indicated by the downlink ANBR information is smaller than a receiving bitrate for reception of the speech of the multimedia telephony session.

13. The one or more non-transitory computer-readable media of claim 11 , wherein the desired receiving bitrate is determined to be the smallest one among a bitrate value indicated by the downlink ANBR information and a bitrate value restricted by each of other bitrate adaptation triggers for the UE, when the bitrate value indicated by the downlink ANBR information is greater than a receiving bitrate for reception of the speech of the multimedia telephony session.

14. The one or more non-transitory computer-readable media of claim 9 , wherein the desired receiving bitrate is determined to be a bitrate value indicated by the downlink ANBR information, when the bitrate value indicated by the downlink ANBR information is smaller than a receiving bitrate for reception of the video of the multimedia telephony session.

15. The one or more non-transitory computer-readable media of claim 9 , wherein the desired receiving bitrate is determined to be the smallest one among a bitrate value indicated by the downlink ANBR information and a bitrate value restricted by each of other bitrate adaptation triggers for the UE, when the bitrate value indicated by the downlink ANBR information is greater than a receiving bitrate for reception of the video of the multimedia telephony session.

16. A method performed by a user equipment (UE), the method comprising:

decoding a session description protocol (SDP) offer message received from a remote UE with which the UE is operable to stream media of a multimedia telephony session, wherein the SDP offer message includes a first SDP attribute parameter indicating support of access network bitrate recommendation (ANBR) capability of the remote UE, wherein the ANBR capability of the remote UE corresponds to an ability of the remote UE to receive ANBR information from a remote RAN to which the remote UE is connected;

encoding an SDP answer message in response to the SDP offer message, wherein the SDP answer message includes a second SDP attribute parameter indicating support of ANBR capability of the UE, wherein the ANBR capability of the UE corresponds to an ability of the UE to receive ANBR information from a RAN to which the UE is connected;

causing transmission of the SDP answer message to the remote UE;

encoding a real-time transport control protocol (RTCP) temporary maximum media stream bitrate request (TMMBR) message for transmission to the remote UE based on downlink ANBR information received from the RAN, wherein the RTCP TMMBR message is distinct from the SDP answer message and indicates a desired receiving bitrate for reception of video of the multimedia telephony session; and

causing transmission of the RTCP TMMBR message to the remote UE.

17. The method of claim 16 , wherein the second SDP attribute parameter is further to indicate support of RAN-assisted codec adaptation of the UE, and the first SDP attribute parameter is further to indicate support of RAN-assisted codec adaptation of the remote UE, and

wherein RAN-assisted codec adaptation of the UE is performed by the UE based on the ANBR information received by the UE from the RAN, and RAN-assisted codec adaptation of the remote UE is performed by the remote UE based on the ANBR information received by the remote UE from the remote RAN.

18. The method of claim 17 , wherein the ANBR information received by the UE from the RAN is downlink ANBR information, the media includes speech, the method comprising:

encoding a codec mode request (CMR)/real-time transport control protocol (RTCP)-application (RTCP-APP) message for transmission to the remote UE based on the downlink ANBR information received from the RAN, wherein the CMR/RTCP-APP message indicates a desired receiving bitrate for reception of the speech of the multimedia telephony session.

19. The method of claim 18 , wherein the desired receiving bitrate is determined to be a bitrate value indicated by the downlink ANBR information, when the bitrate value indicated by the downlink ANBR information is smaller than a receiving bitrate for reception of the speech of the multimedia telephony session.

20. The method of claim 16 , wherein the desired receiving bitrate is determined to be a bitrate value indicated by the downlink ANBR information, when the bitrate value indicated by the downlink ANBR information is smaller than a receiving bitrate for reception of the video of the multimedia telephony session.