Technologies for conference calls with privacy control

1 . A method comprising:

establishing, by a first user equipment (UE), a multimedia session with a second UE;

processing a first session initiation protocol (SIP) message to transition the first UE to a hold state, the first SIP message received from the second UE;

processing a second SIP message received from the second UE, the second SIP message is to add the first UE to a conference call, the conference call different from the multimedia session and associated with an Internet protocol multimedia subsystem (IMS) server associated with the second UE;

processing a third SIP message received from the second UE, the third SIP message including information associated with the conference call;

generating a fourth SIP message to be sent to the IMS server, wherein the fourth SIP message is to subscribe to a conference event associated with the conference call based on the information in the third SIP message; and

processing a notification received from the IMS server based on the fourth SIP message, wherein the notification includes an indication of a list of participants associated with the conference call.

2 . The method of claim 1 , wherein the third SIP message is an UPDATE message, an OPTIONS message, or a RE-INVITE message.

3 . The method of claim 1 , wherein the information is to include a uniform resource identifier (URI) associated with the conference call.

4 . The method of claim 1 , wherein the conference call is a first conference call, the IMS server is a first IMS server, and the second UE is in a second conference call with the first UE and a third UE, the second conference call associated with a second IMS server associated with the first UE, and the method further comprises:

generating a message to the third UE to update a list of participants.

5 . The method of claim 1 , wherein the fourth SIP message is a SIP SUBSCRIBE message and the notification is a SIP NOTIFY message.

6 . An apparatus comprising:

processing circuitry to:

establish, by a first user equipment (UE), a multimedia session with a second UE;

process a first session initiation protocol (SIP) message to transition the first UE to a hold state, the first SIP message received from the second UE;

process a second SIP message received from the second UE, the second SIP message is to add the first UE to a conference call, the conference call different from the multimedia session and associated with an Internet protocol multimedia subsystem (IMS) server associated with the second UE; and

process a third SIP message received from the second UE, the third SIP message including information associated with the conference call;

generate a fourth SIP message to be sent to the IMS server, the fourth SIP message is to subscribe to a conference event associated with the conference call based on the information in the third SIP message; and

process a notification associated with the subscription, the notification received from the IMS server, wherein the notification is to include an indication of a list of participants associated with the conference call; and

interface circuitry coupled with the processing circuitry, the interface circuitry to communicatively couple the processing circuitry with a component.

7 . The apparatus of claim 6 , wherein the third SIP message is an UPDATE message, an OPTIONS message, or a RE-INVITE message.

8 . The apparatus of claim 6 , wherein the information is to include a uniform resource identifier (URI) associated with the conference call.

9 . The apparatus of claim 6 , wherein the conference call is a first conference call, the IMS server is a first IMS server, and the second UE is in a second conference call with the first UE and a third UE, the second conference call associated with a second IMS server associated with the first UE, and the processing circuitry further to:

generate a message to the third UE to update a list of participants.

10 . The apparatus of claim 6 , wherein the fourth SIP message is a SIP SUBSCRIBE message and the notification is a SIP NOTIFY message.

11 . One or more non-transitory computer-readable media having instructions that, when executed, cause a processing circuitry to:

establish a multimedia session between a first user equipment (UE) and a second UE;

process a first session initiation protocol (SIP) message received from the second UE, the first SIP message to transition the first UE to a hold state;

process a conference call received from the second UE, the conference call associated with an Internet protocol multimedia subsystem (IMS) server associated with the second UE; and

process a second SIP message received from the second UE, the second SIP including information associated with the conference call;

generate a third SIP message to be sent to the IMS server, the third SIP message is to subscribe to a conference event associated with the conference call based on the second SIP message; and

process a notification received from the IMS server based on the third SIP message, wherein the notification is to include an indication of a list of participants associated with the conference call.

12 . The one or more non-transitory computer-readable media of claim 11 , wherein the second SIP message is an UPDATE message, an OPTIONS message, or a RE-INVITE message.

13 . The one or more non-transitory computer-readable media of claim 11 , wherein the information is to include a uniform resource identifier (URI) associated with the conference call.

14 . The one or more non-transitory computer-readable media of claim 11 , wherein the conference call is a first conference call, the IMS server is a first IMS server, and the second UE is in a second conference call with the first UE and a third UE, the second conference call associated with a second IMS server associated with the first UE, and the instructions, when executed, further cause the processing circuitry to:

generate a message to be sent to the third UE, the message to update a list of participants.

15 . The one or more non-transitory computer-readable media of claim 11 , wherein the third SIP message is a SIP SUBSCRIBE message, and the notification is a SIP NOTIFY message.

16 . The one or more non-transitory computer-readable media of claim 11 , wherein the notification is a SIP NOTIFY message.