450i TVWS?

So now that the rules for TVWS are final, any plans for the 450i in the UHF white spaces? The interference has become so bad that we're honestly thinking about abandoning 900MHz altogether. FSK hasn't provided enough bandwidth for several years now and OFDM on noisy 900 I fear won't be worth the investment. And the noise is only going to get worse as the power company rolls out smart meters all around us.

I've asked this question a few times to various engineers at Cambium and I believe the answer ATM is no... there are no plans for a TVWS product. That being said... I'm not sure how familiar you are with TVWS rules and channels. If you live near a city there are typically very few channels to choose from. There are a number of databases on the internet to see if there are any channels available near you. The other issue is that the channel widths are small, like 6MHz and while advanced LTE systems allow for channel aggragation, no one is currently producing a low cost LTE base station for TVWS, in addition, I'm not sure if the FCC would allow devices in this band that perform channel aggragation. Lastly, there is no guarentee that you can keep a channel or channels. Your radio is connected to a database, on start up the radio asks the database what incumbant users are tying up channels and whatever is left is what your radio chooses. Let's say another TVWS WISP starts up shop in your area... you'll have to work with them to divvy up the available spectrum... let's say an incumbant changes channels or uses more channels... too bad for (both of) you. One last thing... the antenas for this spectrum are huge (if you thought 900MHz antennas were big!) and hardly anyone is making them... last time I researched a MIMO antenna isn't even available so you'd have to use two antennas at the base station and two antennas for every subscriber if you're using a MIMO system.

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We do bump into the Chicago broadcast zone on the northern part of our network, but the majority of our 900 coverage is pretty rural and there are lots of channels available.

I just don't know what direction to go at this point. 900 sucks. And we've already tried blasting through the trees with the 3.6 450 and it didn't do it. 3.65 LTE isn't going to do any better and we're not going to throw away money on that.

The power co's plan is to roll out smart meters in about a year. It's all 900 FHSS. Everyone else that has had to content with smart meters had to abandon 900. I have no doubt we'll have to do the same. So I need something soon.

If Cambium doesn't want to do it, then I'll find something else.

Hi Geroge,

Why do you believe that LTE will not perform better for Nlos then the 450?  I agree that the 450 platform is not a good Nlos solution in the 3650 band.  We have 3 sites deployed and it is of very limited use for us.  We are going to be testing out a LTE solution in about 4 weeks. I am genuinely curious about what testing or compairsons you have performed.

We currently use the PMP320 and I can tell you that it does perform well in Nlos.  Not as well as our FSK900 network but we have about a 85% success rate in switching from 900 to the pmp320 and the research I have performed to this point leads me to believe that an LTE will perform better then the 320 does.

We did try the PMP320 and the results were no better than 900 FSK. LTE on 3.65 is not an economical solution.

@George Skorup wrote:

LTE on 3.65 is not an economical solution.

Hmmm... yes and no... depends on how you choose to deploy. If you want maximum throughput and the best non/near-LOS penatration then you have to use all the chains on your LTE eNodeB on one sector... this of course significantly increases the cost of lighting up a site with 360 deg coverage. Of course it also helps deploying to an area with a high population density, but if you have a high enough install fee and high enough ARPU, you could get away with deploying in lower density areas.

If you're trying to deploy in an area with low density, but you're not running into near/non-LOS hurdles, you can split up the chains on an eNodeB amongst multiple sector antennas to provide 360 deg coverage. The trade offs being lower per-sector throughput, and reduced near/non-LOS performance as mentioned.