The Effects of Non-P25 Digital Systems on Interoperability

Post by **Wowbagger** » Wed Jul 17, 2013 11:54 am

http://mccmag.com/onlyonline.cfm?OnlyOnlineID=395

A rather interesting article on non-APCO-25 and interoperability.

Post by **escomm** » Thu Jul 18, 2013 7:25 am

Interesting indeed.

Especially how the interop channels are analog.

I guess P25 doesn't equal interoperability. It's merely the 800lb gorilla in the room.

KF5LSC · Post by **KF5LSC** » Thu Jul 18, 2013 11:37 am

So, as long as we're all on the same system, we have interop, right?

MTS2000des · Post by **MTS2000des** » Thu Jul 18, 2013 1:15 pm

One thing that SHOULD be done is to require that all x-TAC repeaters be crossband. For example, if you have a 7/8-TAC-X, it should be located and linked to a corresponding V and U-TAC x repeater. That way, no matter what RF band or format of radio a person has, they can still talk if needed. If the purpose of X-TAC is interoperability, then cross band is the way to go. It would not cost much. Certainly cheaper than expensive trunking system overlays or some unrealistic pipe dream of some nationwide public safety radio network.

Mobile X-TAC repeaters should be standard required equipment in any MCV or SOW.

Jim1348 · Post by **Jim1348** » Thu Jul 18, 2013 5:32 pm

I know of organizations that selected MOTO TRBO rather than APCO P25 because of the cost. It is a concern to me.

p47r4ck · Post by **p47r4ck** » Thu Jul 18, 2013 7:36 pm

Jim1348 wrote:I know of organizations that selected MOTO TRBO rather than APCO P25 because of the cost. It is a concern to me.

I found it interesting that the author recommended that radio manufacturers match and/or lower the price of the P25 gear to that of DMR / NXDN / etc

Curious if the Motorola brass is thinking they shot themselves in the foot with TRBO and marketing it to public safety.

Putting aside the large LEA's and/or County & Statewide radio networks with 7-figure annual budgets and teams of sysadmin's to mind to them... I wonder what the going rate for an APX4000 Model 3 is for an LEA versus a high-tier 2.0 TRBO portable like the XPR7550.

The immediate 2:1 jump on repeater frequencies is has got to be tempting along with basic security to cut out "ease dropping" (read : monitoring). On the mobile side, I imagine the GPS "presence" options on TRBO have to be appealing to dispatchers too. The bells and whistles of TRBO won't cross over to a non-MOTO radio... but basic voice should right?

From a monitoring perspective : I personally was excited to see "P25" IMBE decoding capabilities added to the consumer scanning market with the nods from Uniden & GRE over the past decade (it'll be 10 years in December that the BC796D came out). If the LEAs that are strapped for cash are heading this route, perhaps we'll start to see DMR scanners coming up (AMBE+2 is no spring chicken either, ETSI went with it in 2006!)

At the end of the day : I'm glad that both TRBO & P25 radios can still do analog FM... my life may depend on the easy interop someday!

Bill_G · Post by **Bill_G** » Fri Jul 19, 2013 5:19 am

P25 interop only exists at the CAI on simplex and repeater pair channels. As soon as a system uses trunking, they lose their interop capability as well as their multiple vendor sources. That is what TETRA tried to do - add in trunking compliance. P25 interop is in many ways a pipe dream.

As for interference between DMR and analog co-channel users - yep. The FCC didn't reserve channels for DMR use only versus analog use only. What we're seeing is channels becoming unusable by incumbent analog licensees because someone has implemented a licensed data system, especially the M2M type (machine to machine). ie: trunking control channel continuous overhead transmissions, remote control systems, inventory and asset tracking systems, SCADA. Even at low power (1 to 4W), handheld units can be heard much further than their useful footprint especially as a co-channel receiver's elevation increases. So, a low power UHF wireless inventory system on forklifts in a warehouse is heard miles away by a construction crane operator.

Post by **escomm** » Fri Jul 19, 2013 7:15 am

Hey guys is now a good time to talk about Phase 2 failsoft having only 1 timeslot? Real cool how you can halve your infrastructure investment.... til something breaks...

Post by **escomm** » Fri Jul 19, 2013 7:20 am

Bill_G wrote:P25 interop only exists at the CAI on simplex and repeater pair channels. As soon as a system uses trunking, they lose their interop capability as well as their multiple vendor sources. That is what TETRA tried to do - add in trunking compliance. P25 interop is in many ways a pipe dream.

As for interference between DMR and analog co-channel users - yep. The FCC didn't reserve channels for DMR use only versus analog use only. What we're seeing is channels becoming unusable by incumbent analog licensees because someone has implemented a licensed data system, especially the M2M type (machine to machine). ie: trunking control channel continuous overhead transmissions, remote control systems, inventory and asset tracking systems, SCADA. Even at low power (1 to 4W), handheld units can be heard much further than their useful footprint especially as a co-channel receiver's elevation increases. So, a low power UHF wireless inventory system on forklifts in a warehouse is heard miles away by a construction crane operator.

But... But... Radiosoft said there wouldn't be any interference...

Post by **Wowbagger** » Fri Jul 19, 2013 7:23 am

Bill: I don't know why you say trunking breaks interop - the trunking standard is well defined, and is implemented by multiple vendors. All that is needed is to configure the system to allow the user on - which will be the case for any trunking system that does any form of authentication (read: any sane system).

escomm - doing TDMA without a shared sync reference isn't possible - uses of one time slot will stomp on the other time slot. So without infrastructure to provide that time sync (which is rather the point of fail soft - to continue to operate without infrastructure), you really can only do one time slot.

Post by **Wowbagger** » Fri Jul 19, 2013 7:25 am

Bill_G wrote:As for interference between DMR and analog co-channel users - yep. The FCC didn't reserve channels for DMR use only versus analog use only. What we're seeing is channels becoming unusable by incumbent analog licensees because someone has implemented a licensed data system, especially the M2M type (machine to machine). ie: trunking control channel continuous overhead transmissions, remote control systems, inventory and asset tracking systems, SCADA. Even at low power (1 to 4W), handheld units can be heard much further than their useful footprint especially as a co-channel receiver's elevation increases. So, a low power UHF wireless inventory system on forklifts in a warehouse is heard miles away by a construction crane operator.

But Cognitive Radio and dynamic spectrum allocation will fix that (he said, tongue firmly in cheek).

motorola_otaku · Post by **motorola_otaku** » Fri Jul 19, 2013 7:56 am

escomm wrote:Hey guys is now a good time to talk about Phase 2 failsoft having only 1 timeslot? Real cool how you can halve your infrastructure investment.... til something breaks...

If you're (un)lucky enough to be deploying a multi-site system a geographically-separated redundant prime will solve that. Then you just have to keep your pipe up between sites.

Wowbagger wrote:Bill: I don't know why you say trunking breaks interop - the trunking standard is well defined, and is implemented by multiple vendors.

Harris' wacky implementation of WACN/voice channel NAC kind of shoots that in the foot. Getting a Harris radio to play on Moto P25 is relatively simple; getting a Moto radio to play on a Harris system is much more convoluted. Ditto for EADS/Cassidian systems.

MTS2000des · Post by **MTS2000des** » Fri Jul 19, 2013 11:41 am

trunking prohibits interop because it allows the creation of nice, walled gardens where politics prevail over technology and often become a barrier to end user interoperability.

Here in Atlanta metro we have a prime example of this. There are about 12 disparate trunked radio systems, most of them P25 phase 1, most of them from one vendor. Only two are currently connected via ISSI.

Several run proprietary encryption across the board. Some have indicated they want nothing to do with ISSI. We have one county that is working hard to replace their 22 year old Smartnet II system, yet a handful of snobby cities went out and created their OWN radio authority (with the blessing of state law) and want nothing to do with the new county system, nevermind these cities are already subscribers on the current county system for the past 20 years and will be building out what is essentially a duplicate network. Nevermind their spec calls for proprietary encryption and the county's new P25 phase 2 system does not.

Then the issue of ISSI becomes one of EVERYONE having to have the same system releases, good luck coordinating this between disparate governments. We can't even get some of these people to pick up a telephone and agree to talk to each other.

No amount of technology can fix that. And sometimes, the more complex it is, it can just further become a barrier.

Trunking systems are great, when everyone is a subscriber.

tvsjr · Post by **tvsjr** » Fri Jul 19, 2013 4:58 pm

MTS2000des wrote:trunking prohibits interop because it allows the creation of nice, walled gardens where politics prevail over technology and often become a barrier to end user interoperability.

Here in Atlanta metro we have a prime example of this. There are about 12 disparate trunked radio systems, most of them P25 phase 1, most of them from one vendor. Only two are currently connected via ISSI.

Sounds like D/FW. Well over 30 systems - type 2, P25 phase 1, Brokensky, varying levels of crypto, etc. Some play nicely together, some don't.

Sadly, this will only be fixed when the state and/or federal government runs it. And, they will screw it up so bad that it will cost billions, will never produce a functional system except in a lab somewhere, and at the end of the day will have worse reliability than two tin cans and a string.

motorola_otaku · Post by **motorola_otaku** » Fri Jul 19, 2013 5:55 pm

MTS2000des wrote:Then the issue of ISSI becomes one of EVERYONE having to have the same system releases...

Past (I think) Astro 7.13 the system releases no longer have to match - that's the beauty of ISSI over inter-zone. Only the minimum version required for base ISSI capability is required. Of course Harris systems don't care, as long as the ISSI switch is present.

There are downsides to having everyone operate on the same core system too - one small group runs the whole show, they can be as tyrannical as they choose to be, and if there's any amount of incompetence it makes life difficult for everyone who uses the system. Names withheld.

Birken Vogt · Post by **Birken Vogt** » Wed Mar 12, 2014 4:17 pm

Let me reiterate the problems with P25 as I see it:

1. It costs too dang much for agencies with a limited budget and no federal grants to ever want to buy for normal use.

2. It has shortcomings, real or perceived, compared to the analog it is supposed to replace.

Can anyone tell me why it is so much more expensive than the manufacturers' widely-deployed and successful digital implementations (proprietary or semi-proprietary) that are being used for commercial and some public safety, that as far as I can understand, could be made P25 with the switching of some firmware? P25 is a license-free implementation, is it not?

Post by **escomm** » Wed Mar 12, 2014 4:25 pm

No, it's not. DVSI gets a fee for every radio sold with their chip. Whether the radio does P25 or not.

Birken Vogt · Post by **Birken Vogt** » Thu Mar 13, 2014 6:03 am

I see. I also see TRBO and NXDN listed there. Is the fee they get for P25 any higher than TRBO or NXDN? Or is it just the "public safety premium"?

Also, how does the government justify specifying what seems to be a proprietary implementation, then, if DVSI gets the checks?

Post by **escomm** » Thu Mar 13, 2014 6:57 am

Yeah I'm sure the fee for P25 is infinitely higher than the commercial implementations. Probably just like everything else in the radio world.. "the government has unlimited money so we can charge them whatever the hell we want"

I don't think the government formally specified P25 per se, but rather APCO "certified" the standard just like ETSI "certified" DMR and gave them their name. APCO sounds like serious business and the marketeers have taken full advantage. Someone here has the greatest signature for two way radio I ever saw.... "Analog was already interoperable" and that is proven with the national interop channels... at least the ones that aren't 700MHz.

P25 does not equal interoperability, proper prior planning equals interoperability... even analog needs proper programming... as those 19 firefighters in AZ found out... the hard way =[ Quite sad that 10 minutes of programming before they headed out probably would have saved their lives

Post by **wavetar** » Tue Mar 18, 2014 12:12 pm

escomm wrote: P25 does not equal interoperability, proper prior planning equals interoperability... even analog needs proper programming...

Well said & very true. People confuse interoperability with proper planning and implementation all the time. The point of P25 was to define an open digital standard that all manufacturers could adhere to, giving a common digital platform that, like analog, was conducive to implementing in-band interoperability if needed. The concept of P25 is great...the price required to implement it versus analog is simply ridiculous.

If P25 didn't exist at all, there would be a plethora of neighboring systems using a dog's breakfast of proprietary digital schemes, making interoperability an even bigger challenge. Some of that exists today anyway, but it would be far more prevalent.