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Push-to-Talk over Cellular
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References Proposed by Ericsson, Motorola, Siemens, Nokia
Push-to-talk over Cellular (PoC); User Requirements; PoCRelease 1.0
Push-to-Talk over Cellular (PoC); Architecture; PoC Release 1.0
Push-to-Talk over Cellular (PoC); List Management and Do-not-Disturb; PoC Release 1.0
Push-to-Talk over Cellular (PoC); Signaling Flows; PoC Release1.0;
Push-to-Talk over Cellular (PoC) User Plane; Transport Protocols;PoC Release 1.0;
Push-to-Talk over Cellular (PoC) User Plane; (E)GPRS / UMTSSpecification; PoC Release 1.0;
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What is Push-to-talk
Basically behaves like a Walkie-Talkie phone
Voice: RTP
Voice:RTP
TalkingListenTalking
Listen
JoanJohnson
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What is PoC Push-to-Talk over Cellular
Based on 3GPP IP MultimediaSubsystem (IMS)
Access Network utilizes UTMS GPRSnetwork
Support group talk
Utilize RTCP for floor control
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Why PoC Users view
Theres usually one talking and another listeningin a phone call
Save bandwidth = save money Advanced services: group talk, auto-answer, floor
control
Operators view
Advanced service: compete against other operator,increases revenue Users tend to use this service more often and
longer = more money
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PoC Architecture
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Summary of basic features 1-to-1 communication feature
Instant personal talk
Request to talk
Group talk features Chat group talk
Instant group talk Ad-hoc instant group talk
Instant personal alert
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User identification and
addressing Email style (URI)
Telephone number (TEL URL)
Contact list management
User list
URI
Display name
Group identity URI
Display name
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Access management Do-not-Disturb
Reject list *
URI
Access list
*
URI
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PoC Server SIP signaling
SIP session handling RTP and RTCP signaling
Policy control for access to groups
Group session handling Do not disturb functionality
Floor control functionality
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GLMS (Group and List
Management Server) Users use GLMS to manage groups, contact lists and
access lists and Do-not-Disturb indication
contact list : a kind of address book group list : users can define PoC group
access list : who is allowed to initiate talk session(Only used by PoC server)
Do-not-Disturb (DnD) : set to block all incoming talk
session request UE-GLMS interface : HTTP/XML protocols shall be
used or WAP
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High level procedures Early Session dialog establishment
Early media procedure Late media procedure
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Early session and auto answer
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Early media and auto answer
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Late media and manual answer
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Floor control Utilize RTCP to ensure singular access to the
PoC media resource
Floor request : UE requests PoC server Floor grant : PoC server notifies UE Floor taken : PoC server notifies UE Floor deny : PoC server notifies UE
Floor release : UE notifies PoC server Floor idle : PoC server notifies UE Floor revoke : PoC server revokes the media
resource
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UE state transition diagram
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PoC server transition diagram
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Floor Request Procedure
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Nearly Simultaneous Floor
Request
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Floor Release Procedure
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Example of an instant group talk session