PMR
Getting priority access to an LTE network F
ollowing demonstrations of a hybrid Tetra/ LTE system for mission-critical users at last
May’s TETRA World Congress, Alcatel-Lucent showed a further refi nement of the technology at PMR Expo. “We are showing the impact of quality of service on transmitting video”, ex- plains Jérôme Brouet. “Here we have two live cameras connected to two LTE terminals. One terminal is confi gured without quality of serv- ice [management], using best eff ort; and one terminal is working with confi gured quality of service.” When the network is uncongested, both
halves of the big screen show clear pictures re- layed from a nearby camera. But as M Brouet loads up the network with simulated data traf- fi c, the picture starts to change. “You see that the video without quality of service is going into blocks and it’s freezing. We also see that there are time-outs. We’ve put some ping windows here and you can see that packets did not go through.” Meanwhile, on the QoS side of the screen,
the video stream plays on without degradation. “It’s a demonstration to see how powerful the LTE toolboxes are to manage quality of service, priority and all of those type of things, so that you can actually decide which fl ow, when there is an incident to manage, is the fl ow to put pri- ority on”, he says. “An LTE bearer is established
On the Alcatel-Lucent stand, Jérôme Brouet demonstrates ‘quality of service’ management. On the left side of his split-screen video display, the picture has frozen because of heavy traffi c on the network; but the other half, benefi ting from QoS control, shows perfect live video
end-to-end and each LTE bearer has specifi c quality-of-service rules. T ose rules are popu- lated in the base station, in the core network, everywhere in the LTE network. “And those rules are pre-confi gured in an-
other element of the LTE, which is called the PCRF [Policy, Charging and Rules Function]. You populate the rules there and you can modify the rules when you want. “Let’s say you have default settings for all your
fi rst responders – so they have all equal prior- ity, they have diff erent levels of quality of service for diff erent applications that they have access to. And then if there is an incident, maybe you want to dedicate a Team A and a Team B to this
incident, but not Team C. But Team C might be in the same location as Team A and Team B. “So you will change the settings of those
teams. You might have templates present to ease the process in the command and control room, to load new rules to this PCRF that I mentioned before. And then the rules can be populated to the diff erent equipment in the LTE network.” In this way, the rules can be changed dynami-
cally to give team A and team B priority over Team C. “I think this is one of the powerful things of LTE, on top of throughput, latency and so on”, M Brouet adds.
• Information:
http://lte.alcatel-lucent.com
Serving video to fi rst responders R
elaying live video at the scene of an emergency will be a task for LTE, but
tools for displaying and using video will also be needed. A solution developed by Alcatel- Lucent uses a central server to manage multiple video sources and destinations. “The equation we had to solve here was
a three-dimensional equation”, explains Jérôme Brouet, of the company. “The fi rst one was how to minimize the consump- tion of radio bandwidth when you want to transmit multiple video information to somebody in the fi eld, because video is quite bandwidth-consuming. “The other thing is that when you are
having mobile devices – smartphones, tablets, whether they are ruggedized or not – they have limited capabilities in terms of processing, especially when it comes to displaying video information. The CPUs and the graphical processors that are there are capable of handling one fl ow, but when
14
you have to decode multiple fl ows at the same time they usually fail. That’s the second dimension of the equation we had to solve. “And the third one was – when you have
video, what do you do with it? Why can’t you share videos between people? “So what we do is we have a client/server
solution whereby most of the processing is done remotely. Here we have an example of an application where we show four dif- ferent streams. It shows us four different, independent streams on the screen, and the end user can manipulate them as if it were a single stream – so you can zoom in, zoom out or whatever. But in terms of the fl ow that is sent to these tablets, it is actually one video fl ow – but it displays like it was different video fl ows.” In addition, a fi rst responder on the
ground can select one of the incoming video streams and share it with his team.”
Split-screen video feeds on a tablet and a mobile phone: displays from Alcatel- Lucent’s FRV (First Responder Video) technology, which allows different views of the same event to be shared at the scene
LAND mobile January 2013
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