INSIDE THE HARRIS/LG IN-BAND MOBILE DTV SYSTEM

NAB will be the formal coming out for the new in-band mobile DTV system cooked up by Harris and LG Electronics.

The two developers will showcase the system that they have dubbed MPH at a Sunday night (April 15) press event, and they will be demonstrating it live throughout the convention on a bus as it rolls around Las Vegas.

MPH is competing with the A-VSB system developed by Samsung and Rohde & Schwarz, which attracted considerable attention at the Consumer Electronics Show in Las Vegas in January.

Like A-VSB, MPH promises to give TV stations the ability to broadcast directly to mobile and portable screens even in fast-moving cars without having to go through cellphone providers and other middlemen.

Sinclair Broadcast Group CEO David Smith has been outspoken about the potential for the technology, seeing it as a way to create a go-everywhere pay TV service.

In this interview with TVNEWSDAY, Harris's Jay Adrick explains how MPH works and how Harris and LG intend to bring it to market within the next year.

And edited transcript follows:

So, what exactly is this thing and how does it work?  

MPH is an in-band mobile DTV system, MPH standing for mobile-pedestrian-handheld. It's for delivering to devices that would be used in those situations. It's in-band, meaning it uses a portion of the transport stream capacity.

To be deployed, it requires that the broadcasters add encoding equipment for the MPH channels and multiplexing to be able to mux in the MPH channels with the standard ATSC stream. It also requires a different exciter to generate both the ATSC and the MPH signals simultaneously.

And you believe that it is fully compatible with the 8-VSB system?

Yes. Our partner, Zenith [a unit of LG Electronics], as you know, was the developer of the 8-VSB modulation scheme and they understand it extremely well. We took great care to make certain that the system is fully compatible with all of the receiving gear out there and all of the elements of the standard, including such things as distributed transmission, PSIP and other elements crucial to delivering proper terrestrial broadcast coverage.

How does it differ from the A-VSB mobile system being developed by Samsung?

We believe we are more bit efficient in the use of the transport stream so we can put more payload in a similar amount of bandwidth or we can, for a similar payload, use less bandwidth out of the transport stream.

We also do not rely on diversity antenna operation to receive the signal. On portable and handheld devices and mobile devices, we use a single antenna. And again, we are fully compatible with the ATSC standard. I think if you were to drill into the inner workings of A-VSB, you would find there are compatibility issues with its ability to work with things like the ATSC-approved distributed transmission method.

What kind of field testing have you done?

We conducted field tests in Columbus, Ohio, at WBNS, a CBS affiliate owned by Dispatch. We ran the tests for about two weeks and, during the testing period, we had two different vans out in the marketplace.

We were able to capture both of the mobile streams that we were broadcasting, and we were able to compare them against the main ATSC stream.

We did some very intense pre-planning in terms of routes to get a variety of terrain and obstructions such as high-rise buildings in the downtown area, hills, foliage and a lot of the other things that would typically interfere.

We also did distance runs in various radials out from the transmitting plant. We did high-speed runs on the Interstate. We did a series of walking tests, where we did a 100-foot walking path in many different locations.

How did you do?

We did extremely well. We were actually surprised at how good the coverage was. We had a couple of minor spots in downtown where we took hits, but we never lost the signal per se. Outside of downtown, we had rock solid coverage whether we were driving or walking. We took people out on the interstate 45 miles from the transmitter site going 70 miles an hour. People were just absolutely watching a locked up solid picture.

And when you say it took a couple of hits in downtown areas, what do you mean? Do you mean that the picture froze up?                                               

It would be a momentary freeze. I'm sure you've used a cell phone in an urban canyon situation and you had the cell phone drop on you or had a brief interruption in the audio. It would be something like that.

Let's talk about the bit budget here. How many bits was WBNS using for HD and how much for MPH?

We had 14 megabits allocated to the HD channel and we had 4.4 megabits allocated for the two mobile channels.

So, one channel would require 2.2 megabits.

No. It's not a linear function. There's a certain amount of channel overhead that's for the mobile service. Then, after that, the more channels you add the more efficient it gets. I don't know the exact ratio. It depends on modes of operation so there are a wide variety of combinations.

This is still a work in progress, I assume.

Yes. It's technology in development. What we have today is the transmission system. There's a lot of work that has to be done yet in the area of audio and encoding and some of the other pieces of the system.

The folks at LG are working on the silicon for the receivers and that will be reduced from the development platforms that we have today, which are not portable devices. They're laboratory devices.

What do you have planned for the NAB demonstration?

We'll be on the air on KVCW, which is the Sinclair-owned CW affiliate, and we'll be conducting mobile tours around Las Vegas. We have a 16-passenger bus that's equipped with a 42-inch display. On that display, you'll see the two mobile channels as well as the main ATSC channel from the KVCW broadcast.                         

And these mobile channels will have completely different content?

Actually, one of the channels will be an MPH replication of the KVCW programming so that you'll be able to compare and contrast the main channel with the mobile channel. And then we'll have completely different programming on the second mobile channel.

What are your plans for bringing this to market?

Our goal is to develop a high level of broadcaster interest in the technology. That's the first step and we're well on the way to that. We've got a large number of broadcast groups that have already seen the technology. Some of them have seen it in Chicago, where we were running a very low-power test. Some of them have been out to Columbus to see our field tests and the rest of them are obviously joining us in Las Vegas.

Post Las Vegas, we will be probably be going to several markets for field trials, testing some variations of the signal configuration and doing some other enhancements that were not ready for NAB.

How long from where it is now to getting a real receiver in my hands?

We have active development programs right now for the exciter. The multiplexer is already developed and the encoder is being developed. We will have all of those products pre-NAB next year. LG is moving ahead with the silicon receiver development. Itexpects to have chips late this calendar year and to have receiving devices before NAB next year.

What about standardization at ATSC?

Our plans in terms of standardization right now is to get the industry to buy in to our technology, and, if we get the industry buy in, we would more than likely take it to a standards body such as ATSC for standardization.

I  think it's significant that Sinclair is working with you in Las Vegas since it was so closely involved with Samsung in its field testing.

It's very significant yes. They've been very supportive. They've been out to see the system in Columbus Ohio. They've been out to see it in the lab.

And David Smith has been vocal about the potential of the in-band mobile broadcasting. It's one thing to have a new technology. It's another to have a business idea to go with it.

Yes. But I wouldn't limit it to David Smith.

He's been the guy out front.

Right. He's been the guy out front. There are several others that have been out doing a lot of missionary work, but haven't been as public as David. You'll see that when you see who's at the press event Sunday night.