Wireless New White Space Rules

[mbenonis]

Before the rumour mill starts up here on how wireless mics are doomed, I'll get into the report as soon as its released and post some thoughts on it here. Just hold your horses.

 

[museav]

What, you're not going to wait until after the almost inevitable interpretations and lawsuits?

 

[mbenonis]

I had a chance to read through the Memorandum Opinion and Order, and here are the salient points for wireless mic users. A more complete analysis is coming.

1) Spectrum sensing has been dropped for devices that can geolocate and query a database.
2) Two TV channels (the two closest to Channel 37, one on each side) will be free for wireless mic users across the US. These channels will vary by location.
3) Users who use all available spectrum in the two free channels (where you can fit up to eight mics, according to the FCC*) and also all VHF bandwidth between 174-216 MHz (remember what I've been saying for years about keeping VHF mics!) can apply for database protection to operate in other UHF TV Channels.
4) TV Band Devices may only use up to 4W ERP (fixed) and 100 mW (mobile and portable) in a TV channel. THey must stay 1 km (fixed) and 400m (mobile/portable) from registered database users. They cannot operate within a TV Channel's protected contour, and a whole bunch of other exclusion areas.

The bottom line here is that there are a number of protections available to us, starting with the reserved channels around Ch 37. If you set up your Wireless Mic system right and buy quality, reputable equipment, it will work just fine. If you try to cheap out though and buy Bottom Dollar brand wireless, you're in for it.

I'll write up a much more complete summary in the next week or so, including test results from a test we are doing at Virginia Tech to determine the real-world ramifications from TV Band Device interference (suffice it to say we have obtained some prototype devices and an experimental license to conduct the tests [WE9XKX for those interested in looking it up]).

More to come!

Mike

*On fitting that many mics. My rule of thumb has always been 1 Mic per MHz of spectrum. It is reasonable, with good quality equipment, to fit one mic per 750 kHz of spectrum, which will yield about eight mics per 6 MHz of spectrum. I would say you need something like Shure ULX or UHF-R, or Sennheiser Evo 500 or 2k or 3k/5k, or Lectro gear to do this, but don't hold me to it because I haven't tried it. I'll see what I can drum up for you.

 

[MaxS]

Thanks, Mike!

If anyone is interested in reading the press-release or entire 88-page MO&O, they can be found here, respectively:
http://hraunfoss.fcc.gov/edocs_public/attachmatch/DOC-301650A1.pdf
http://hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-10-174A1.pdf

Most key information can be found in sections III.A.2. and III.D.1. A few pertinent key passages that from these sections that Mike also referenced are as follows:

III.A.2.¶25) "TV bands devices may not operate co-channel to a registered low power auxiliary station within a distance of 1 kilometer of the registered coordinates." (Still much debate as to whether this is a practical restrictive radius.)

III.A.2.¶32) "As the general rule, we are not allowing unlicensed wireless microphones and other low power auxiliary devices operating without a license to be registered in the database; these devices will not be afforded protection from interference from TV bands devices on channels where TV bands devices are allowed to operate." (Venues will be allowed to register for protections in the event that all available space allocated for unlicensed use is, in fact, in use.)

III.D.1.¶132) "We are revising our rules to reserve two channels nationwide where TV devices are not permitted to operate to ensure that some spectrum remains available for wireless microphones and other LPAS stations. ... These channels will be the first channels on either side of channel 37 that are unoccupied by broadcast television stations or, if no channels are available on one side of channel 37, the first two channels nearest to channel 37."

 

[MNicolai]

Mike, is there any chance of the changes in the wireless spectrum quieting down anytime soon? For a very long time no one really worried about their wireless mic's, which granted, they operated illegally, but it seems like for the last several years things have been changing every couple months. Not that that's necessarily a bad thing, but it'd be nice to sit back and relax for awhile and not have to worry about our mic's becoming illegal again.

A lot of us expect our wireless systems to have a life expectancy of a solid decade, so I suppose my question is will we be able to let our equipment die of old age or is there good probability we'll have to off-load at some point and replace it with stuff in a different frequency band?

(I know the best answer you can give is speculative opinion)

I'd like to think Shure has our back, but our industry is just too small to have serious leverage on these issues.

 

[museav]

A lot of us expect our wireless systems to have a life expectancy of a solid decade, so I suppose my question is will we be able to let our equipment die of old age or is there good probability we'll have to off-load at some point and replace it with stuff in a different frequency band?

(I know the best answer you can give is speculative opinion)

At this point, a decade may be wishful thinking. There seems to be a shift from industries and technologies using the RF spectrum having established user bases and tending to make changes slowly to applications and groups that want to introduce new technologies and that think of obsolescence in terms of years or even months rather than decades. In the past a change like this would not have happened in the same year as some of the other changes, there would have been years of study, debate and testing, but now you apparently have powerful groups involved that want change to happen quickly (as long as it benefits them).

Overall, the response I've seen has been generally positive, except for concern over the rather optimistic view of how many system can operate on a channel which some feels shows the people making these decisions are doing so based on some incorrect or overly optimistic understandings. The biggest gain seems to be the establishment of the two 'safe harbor' channels. However, there are many, many unknowns at this time from when the database will be available to how the safe harbor channels for a market will be identified to end users to arguments over realistic losses and clear areas for broadcasters to when, if ever, any TVBD operation will be practical.

A critical aspect of this is that it apparently may still be possible to use wireless mics that are not in the database or operating in the 'safe harbor' channels provided that they do not interfere with licensed users or TVBD. And nothing prevents you from not locating a TVBD device or prohibiting portable TVBD devices in your facility, a well built space and directional antennas may go a long ways toward allowing wireless systems to continue to operate without interfering with or receiving interference from TVBDs.

There apparently some in the IT industry who are saying this is greatly for naught as there the cost of building and operating widespread TVBD systems may not be able to be justified when other systems such as 4G and LTE are already being implemented and TVBDs may have to compete with those.

 

[mbenonis]

Overall, the response I've seen has been generally positive, except for concern over the rather optimistic view of how many system can operate on a channel which some feels shows the people making these decisions are doing so based on some incorrect or overly optimistic understandings.

While up to eight systems within a six megahertz block may seem high, it is possible to do with professional quality equipment and careful planning. I don't claim it can be done with $300 wireless systems, but certainly tour grade equipment can handle this. The bad news is that it places it out of a lot of people's reach, but--one must ask whether a junior high school, for instance, needs twenty-four channels of wireless in their space or not.

The biggest gain seems to be the establishment of the two 'safe harbor' channels. However, there are many, many unknowns at this time from when the database will be available to how the safe harbor channels for a market will be identified to end users to arguments over realistic losses and clear areas for broadcasters to when, if ever, any TVBD operation will be practical.

These are good questions, to which I don't have an answer. I would say the best bet at the moment is to look at the FCC"s Media Bureau database and see what TV channels on either side of 37 are unoccupied according to the FCC. I wish there were a better way at the moment, but there doesn't appear to be one.

A critical aspect of this is that it apparently may still be possible to use wireless mics that are not in the database or operating in the 'safe harbor' channels provided that they do not interfere with licensed users or TVBD. And nothing prevents you from not locating a TVBD device or prohibiting portable TVBD devices in your facility, a well built space and directional antennas may go a long ways toward allowing wireless systems to continue to operate without interfering with or receiving interference from TVBDs.

Absolutely. First off, the presence of safe-harbor channels does not prohibit you from using other channels, just as you have in the past. The only difference is that you won't be protected unless you can show that you have used up the two safe harbor channels effectively (what effectively means has not been defined well).

Second, I personally think we are WAY overestimating the damage a WSD will cause to a wireless mic. First, the portable WSD's are limited to 100 mW over 6 MHz. That's not a lot of power, and it's definitely not a lot of power within the bandpass of a wireless mic receiver. I think what will happen is that the net effect will be a general rise in the noise floor for us, nothing more.

Directional antennas (WITHOUT preamplifiers) are definitely the way to go, especially if they can be on the stage facing away from the audience (for instance, on a catwalk above the house).

There apparently some in the IT industry who are saying this is greatly for naught as there the cost of building and operating widespread TVBD systems may not be able to be justified when other systems such as 4G and LTE are already being implemented and TVBDs may have to compete with those.

I think the real boon for WSD's will be backhaul for Wi-Fi deployments, especially in rural areas. I don't see a huge market for consumer handheld devices--we can do much better with LTE, WiMAX, and other standards.

 

[mbenonis]

Mike, is there any chance of the changes in the wireless spectrum quieting down anytime soon? For a very long time no one really worried about their wireless mic's, which granted, they operated illegally, but it seems like for the last several years things have been changing every couple months. Not that that's necessarily a bad thing, but it'd be nice to sit back and relax for awhile and not have to worry about our mic's becoming illegal again.

A lot of us expect our wireless systems to have a life expectancy of a solid decade, so I suppose my question is will we be able to let our equipment die of old age or is there good probability we'll have to off-load at some point and replace it with stuff in a different frequency band?

(I know the best answer you can give is speculative opinion)

I'd like to think Shure has our back, but our industry is just too small to have serious leverage on these issues.

I would say that if you buy wireless mics in the upper 500 MHz and lower 600 MHz bands you will be in good shape for years to come.

 

[museav]

While up to eight systems within a six megahertz block may seem high, it is possible to do with professional quality equipment and careful planning. I don't claim it can be done with $300 wireless systems, but certainly tour grade equipment can handle this. The bad news is that it places it out of a lot of people's reach, but--one must ask whether a junior high school, for instance, needs twenty-four channels of wireless in their space or not.

In terms of a theatre that is one thing but how many high school, college and corporate campuses use wireless mics for other venues and events that could occur concurrently? I work with universities that have wireless mics in every larger classroom for ALS support and multiple systems in some of the largest classroom spaces. Then there's the wireless comms for the football team, the wireless mics used by the Media Club for remote shoots on campus and so on. These are applications where wireless systems may be virtually required, in the case of ALS for legal compliance, yet more expensive systems may be impractical. It seems that they considered venues as though they are a single space and not potentially part of a single user in a more encompassing RF environment. Will it be possible for the theatre to register in the database because the classrooms in the neighboring buildings already use all the 'safe harbor' frequencies, or vice versa, when they are all part of one facility or entity?

 

[mbenonis]

In terms of a theatre that is one thing but how many high school, college and corporate campuses use wireless mics for other venues and events that could occur concurrently? I work with universities that have wireless mics in every larger classroom for ALS support and multiple systems in some of the largest classroom spaces. Then there's the wireless comms for the football team, the wireless mics used by the Media Club for remote shoots on campus and so on. These are applications where wireless systems may be virtually required, in the case of ALS for legal compliance, yet more expensive systems may be impractical. It seems that they considered venues as though they are a single space and not potentially part of a single user in a more encompassing RF environment. Will it be possible for the theatre to register in the database because the classrooms in the neighboring buildings already use all the 'safe harbor' frequencies, or vice versa, when they are all part of one facility or entity?

I don't think that will be a huge problem. Yes, multiple classrooms in a building might use wireless mics, but it's pretty unlikely that a classroom at one end of the building will cause a significant problem for a classroom at the other end. You could probably space them 600 kHz apart and be just fine. While I agree that you should certainly consider the whole RF environment, just like in the cellular world it is certainly possible to reuse frequencies (or stagger them) in such a way to pack things in.

 

[WooferHound]

In Britain, the government is compensating wireless mic users for obsoleting their wireless mic equipment because of the reallocating of the frequencies they use.
http://stakeholders.ofcom.org.uk/consultations/pmse_funding/statement/
SAVE OUR SOUND UK issues call to action: - Blue Room technical forum

 

[museav]

Mike, my point was more to the requirement that a venue use the safe harbor frequencies before registering in the database but is what defines a "venue" clarified? For example, I work with a local university that has a proscenium theatre, black box, rehersal hall and concert hall all located within a couple of hundred feet of one another and all sharing a common comms system, including wireless comms in each space, but they are technically in three different, but connected, buildings. Just across the street are a gazebo and quad used for outdoor events that the same groups support and across the quad are the events building and the gym. So what is the venue in terms of being able to register in the database, is it each physical space, each building, the interconnected buildings, the campus or what? I don't know if that kind of situation has been addressed. What is a concern is that because of the educational component I can see some of these facilities being ones that may see some use of TVBDs just as they are currrently filled with WAPs.

The same with many corporate facilities, I've designed a number of corporate buildings that don't have a dozen wireless mics in any one space but that do have more than that in total in the building. Or the church with separate adult and youth worship spaces. How will these relate to what is a venue? Just one of the many questions that seem to need to be answered before applying the ruling is in any way practical.

 

[mbenonis]

Mike, my point was more to the requirement that a venue use the safe harbor frequencies before registering in the database but is what defines a "venue" clarified? For example, I work with a local university that has a proscenium theatre, black box, rehersal hall and concert hall all located within a couple of hundred feet of one another and all sharing a common comms system, including wireless comms in each space, but they are technically in three different, but connected, buildings. Just across the street are a gazebo and quad used for outdoor events that the same groups support and across the quad are the events building and the gym. So what is the venue in terms of being able to register in the database, is it each physical space, each building, the interconnected buildings, the campus or what? I don't know if that kind of situation has been addressed. What is a concern is that because of the educational component I can see some of these facilities being ones that may see some use of TVBDs just as they are currrently filled with WAPs.

The same with many corporate facilities, I've designed a number of corporate buildings that don't have a dozen wireless mics in any one space but that do have more than that in total in the building. Or the church with separate adult and youth worship spaces. How will these relate to what is a venue? Just one of the many questions that seem to need to be answered before applying the ruling is in any way practical.

I'm not so sure it matters how you define a venue. The requirement isn't for each and every venue to fill up all of the safe harbor the channels, just that you make an effort to use the safe harbor channels, other channels that TVBD's can't use or must use low power in (such as adjacent to full power TV'ers), and also high band VHF channels before registering. If the channels are full from one venue or a spread of venues, it doesn't matter...the channels are full. You also need to fit upwards of eight mics in a single TV channel, which is feasible if you use good mics (probably not going to happen with SLX and similar though!)

This excerpt from the the release this month ought to clear it up a bit:

32. Accordingly, we are addressing unlicensed wireless microphones and low power auxiliary devices in our rules for TV band devices as follows. As the general rule, we are not allowing unlicensed wireless microphones and other low power auxiliary devices operating without a license to be registered in the database; these devices will not be afforded protection from interference from TV bands devices on channels where TV bands devices are allowed to operate.59 Entities desiring to operate wireless microphones on an unlicensed basis without potential for interference from TVBDs may use the two channels in each market area where TVBDs are not allowed to operate, as well as other TV channels that will be available in the vast majority of locations. Such entities may consult with a TV bands database to identify the reserved channels at their location, as well as the TV channels that may not be available for TV band devices.60 Entities operating or otherwise responsible for the audio systems at major events where large numbers of wireless microphones will be used and cannot be accommodated in the available channels at that location may request registration of the site in the TV bands data bases. The registration requests must be filed with the Commission. Entities filing registration requests will be required to certify that they are using the reserved channels and all other available channels from 7 – 51 (except channel 37) that are not available for use by TV band devices and are practicable for use by wireless microphones.61 The request to be registered must be filed with the Commission at least 30 days in advance and include the hours, dates or days of the week and specific weeks on which those microphones will be in actual use (on dates where events are not taking place those sites will not be protected) and other identifying information also required of low power auxiliary licensees. Unlicensed microphones at event sites qualifying for registration in TV bands databases will be afforded the same geographic spacing from TVBDs as licensed microphones. We also advise entities responsible for event sites qualifying for registration in TV bands databases that registration does not create or establish any form or right or assurance of continued use of the spectrum in the future.