24-03-2011, 10:54 AM
presented by
Muhammad Shoaib Ahmed
[attachment=10890]
History
PTT available since World War II with limited coverage but minimum charges
In 1996 Nextel begins to rollout iDEN
Push-to-Talk (PTT or P2T), originally introduced in the US by Nextel through its partnership with Motorola
Tata Indicom is the first mobile service provider to nationally launch Push-To-Talk in India
Introduction
PTT in cellular networks is called Push-To-Talk over Cellular (PoC)
PTT is a half-duplex voice service
PTT is a special feature on a mobile phone that combines the functionality of a walkie-talkie or 2-way radio with the normal mobile phone
PoC is a service option for a cellular phone network which permits subscribers to use their phone as a walkie-talkie with unlimited range
What Push-to-talk
Push-to-Talk over Cellular
Push to Talk over Cellular (PoC) is a service option for a cellular phone network which permits subscribers to use their phone as a walkie-talkie with unlimited range. A typical Push to Talk connection connects almost instantly.
PoC Server
RTP and RTCP signaling
Policy control for access to groups
Group session handling
Do not disturb functionality
Floor control functionality
Floor Request Procedure
High level procedures
Early media procedure
Late media procedure
Early media and auto answer
Late media and manual answer
GLMS (Group and List Management Server)
Users use GLMS to manage groups
contact list : a kind of address book
access list : who is allowed to initiate talk session (Only used by PoC server)
group list : users can define PoC group
Do-not-Disturb (DnD) : set to block all incoming talk session request
Why PoC
User’s view
Immediate wireless contact to a pre-defined person or group
Suitable for group of friends, small businesses
Save money
Advanced services: group talk, auto-answer, floor control
Push-To-Talk does not work on distance and is cheaper, faster and more convenient than sending an SMS
Why PoC
Operator’s view
Enhanced voice services
Advanced service: compete against other operator, increases revenue
Users tend to use this service more often and longer = more money
Efficient way of using network resources
PTT Phones
Summary of basic features
1-to-1 communication feature
Instant personal talk
Request to talk
Group talk features
Chat group talk
Instant group talk
Instant personal alert
Limitations/Exceptions
Because the connection happens over a cellular network there is no physical limitation to the amount of distance users are from each other.
If one person is not connected to the network, because of lack of signal, the connection cannot be established.
The only exception to this is with Nextel's DirectTalk, but not connected to the network
CONCLUSION
Technology push but no dominant design yet
The technology has not yet advanced to include push-to-talk services beyond your own network.
There seems to be a strong technology push to provide new services to mobile customers in order to replace the revenues disappearing due to the tough competition between mobile operators