|
When the network is uncongested, both halves of the big screen show clear pictures relayed from a nearby camera. But as M Brouet loads up the network with simulated data traffic, 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 flow, when there is an incident to manage, is the flow to put priority on”, he says. “An LTE bearer is established end-to-end and each LTE bearer has specific quality-of-service rules. Those rules are populated in the base station, in the core network, everywhere in the LTE network. “And those rules are pre-configured in another 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 first responders – so they have all equal priority, they have different levels of quality of service for different 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 different equipment in the LTE network. I think this is one of the powerful things of LTE, on top of throughput, latency and so on.” Serving video to first respondersRelaying 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 first one was how to minimize the consumption of radio bandwidth when you want to transmit multiple video information to somebody in the field, 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. “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 different 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 flow that is sent to these tablets, it is actually one video flow – but it displays like it was different video flows.” (中国集群通信网 | 责任编辑：陈晓亮) |
Following demonstrations of a hybrid