P25 vs DMR vs TETRA: Which Digital Radio Standard Should You Actually Choose?

“Which is better, P25, DMR or TETRA?” is the wrong question, and it is the one most comparisons set out to answer.

They are not three attempts at the same thing. P25 was developed around the requirements of public safety and mission critical land mobile radio, with interoperability between agencies and manufacturers as a central objective. DMR was written to give commercial users a digital upgrade path that reused existing 12.5 kHz plant. TETRA was written for European public safety and large infrastructure operators who wanted a trunked network with data and telephony built in from the start. Each is good at what it was designed for, and the question that matters is which of those problems is yours.

There is also a comparison that rarely gets made, and it is the one with money attached. Your choice of standard determines how many RF carriers a site has to run, which determines how many transmit frequencies you licence, which determines what the ACMA taxes you every year for as long as the system exists. On a twenty path site in a high density area, that difference runs past forty thousand dollars a year.

The Short Answer

The Nominal Efficiency Argument

For years the pitch for each standard was spectral efficiency. At the air interface level, the simple nominal calculation now produces the same answer for three of the four options, and it is worth seeing why, because it clears the way to the differences that still matter.

Three different routes to the same nominal figure. DMR and P25 Phase 2 each split a 12.5 kHz carrier into two time slots. TETRA splits a 25 kHz carrier into four. All three land on one voice path per 6.25 kHz of carrier bandwidth. The DMR standard calls this “6,25 kHz equivalent” efficiency, and that word equivalent is doing real work.

That does not mean their real world spectral efficiency is identical. This is a nominal capacity calculation, and it takes no account of control signalling overhead, guard periods, channel coding, control channel capacity limits, site architecture or frequency reuse, all of which differ between the three and all of which move the delivered figure. Treat the 6.25 kHz as the starting point of the comparison rather than its conclusion.

The odd one out is P25 Phase 1, which is FDMA and gives one voice path per 12.5 kHz carrier. It uses twice the spectrum per conversation of everything else on that list, and that fact has consequences well beyond spectrum, as the licensing section below sets out.

Where They Actually Differ

Spectrum per voice path is a ratio. What you licence and build is a whole number of RF carriers, and that is where the three standards separate.

Two things drive it. The first is carrier granularity: TETRA buys spectrum in 25 kHz units where the others buy it in 12.5 kHz units, so TETRA rounds up in larger steps. The second is where the control channel lives, and the three standards handle it quite differently:

• P25, in the conventional trunked architecture described here, gives the control channel a dedicated 12.5 kHz RF carrier. On Phase 2 that control carrier is itself a Phase 1 FDMA carrier, so it carries no traffic at all.
• DMR Tier III, in its common configuration, puts control signalling on a logical slot of a 12.5 kHz carrier, which leaves the other slot available for payload traffic. The standard also permits configurations with more than one control channel.
• TETRA gives up slot 1 of the main carrier to the main control channel, leaving three traffic slots there. Every additional carrier gives all four.

Put a real requirement through that and the differences are not subtle. For a site that needs twenty simultaneous traffic paths:

Read that last row carefully, because it is the result that surprises people. TETRA needs the fewest carriers by a wide margin, six against eleven, and yet it occupies more paired spectrum than DMR or P25 Phase 2. The 6.25 kHz per voice path figure is identical for all three. The 25 kHz carrier granularity is what makes the difference once you round up to whole carriers.

That is a genuine engineering trade rather than a winner. Fewer carriers means fewer transmitters, a simpler combiner, less combining loss and less rack space. More spectrum means more to find, more to coordinate and more to pay for.

The Cost That Rarely Gets Priced

Here is the part that seldom appears in a vendor comparison, for the straightforward reason that the vendor does not pay it.

Three terms that are not interchangeable

Before the numbers, the vocabulary, because this section moves between three related quantities that are easy to conflate.

• Carrier bandwidth is the RF bandwidth of one transmission channel, so 12.5 kHz for P25 and DMR, 25 kHz for TETRA.
• Paired spectrum is the combined uplink and downlink bandwidth of a duplex channel pair, which is twice the carrier bandwidth per pair.
• Spectrum access is the ACMA licensing term. The schedule defines it by a particular transmit frequency, bandwidth, site or access area and transmit power, and it states that all transmit spectrum accesses are chargeable.

The last of those is what you pay on, and the connection to the first two is not one to one.

The model used here

A land mobile system transmits in both directions. The base station or repeater transmits to the mobiles, and the mobiles transmit back to it. Both are transmit spectrum accesses, so each duplex RF carrier is two chargeable spectrum accesses, not one. The tables below apply that model: twenty one carriers becomes forty two accesses, and so on.

That is the same rule that makes a duplex repeater licence cost twice a simplex one, which is worked through in our breakdown of what a radio licence actually costs.

This is still a simplified illustration rather than a quote for your system. It assumes an ordinary Division 4 land mobile licence in the 403 to 520 MHz band, one transmit access per direction per carrier, and a single site. Real licences vary, and government networks are frequently licensed under different arrangements, including harmonised government spectrum, which prices differently again. Use these figures for the shape of the difference and have your own configuration priced properly before it reaches a budget.

Twenty traffic paths, high density

New licence, excluding GST, calculated from the ACMA apparatus licence fee schedule edition 2026-07.

Under this model, choosing P25 Phase 1 over Phase 2 for the same twenty voice paths costs an additional $41,249 every year, and it continues for the life of the licence. Over ten years that is more than four hundred thousand dollars in tax alone, for a system carrying exactly the same number of conversations.

The same system in a remote area

The ranking changes, and the reason is worth understanding. Where the annual tax dominates, the technology using the least spectrum wins. Where the tax collapses to the minimum, as it does in a remote area because the rate for this band is zero, the one off administrative charge dominates instead, and the technology with the fewest spectrum accesses wins. Those are different technologies. TETRA’s first year cost in a remote area is a little over half the DMR figure.

There is a subtler version of the same effect in a high density area. TETRA has the lowest first year cost there too, at $55,474 against $56,329 for DMR, because its twelve accesses attract far less issue charge. But its ongoing years are dearer, $49,546 against $45,461, because its spectrum is wider. TETRA is ahead for one year and behind from the second onwards.

The same two technologies, the same twenty traffic paths, and the better answer depends on where the site is and how long you intend to hold the licence. That is not a conclusion you can reach from a datasheet.

What Australia Actually Runs

Most published comparisons are written for a North American or European market and the conclusions do not transfer cleanly.

P25 is used extensively in Australian government and public safety networks. The clearest documented case is the NSW Public Safety Network, formerly the Government Radio Network, which the NSW Telco Authority states uses P25 to carry voice and minimal data for frontline emergency services, currently covering over 67 percent of NSW and being expanded toward 85 percent land coverage. P25 is in use in other states as well, although the picture within any one state is usually more mixed than a single label suggests, with P25 networks running alongside older trunked and conventional systems that have not been retired. If you need to interoperate with an Australian government network, P25 is the standard to check for first, and the specific network is the thing to confirm rather than assume.

DMR is widely used in commercial and industrial fleets. It is a natural upgrade path from analogue FM because it keeps the same 12.5 kHz channelisation and can usually reuse existing sites, which removes the largest cost from a migration. The DMR standard describes its 4FSK modulation as constant envelope, which suits existing transmitter plant. Coverage still has to be verified rather than assumed, from the actual radio performance, the propagation environment and the digital reliability you require, but the starting point is favourable.

TETRA has a significant presence in transport, resources and mining, particularly where an operator values trunking, integrated voice and data services, and mature mission critical features as parts of one system rather than as additions to a radio network.

There are exceptions everywhere, particularly in less populated areas where conventional, satellite and mobile network options still make sense, and hybrid or private LTE increasingly sits alongside all three.

Why You Cannot Compare the Datasheets

This is the trap that catches experienced engineers, and it is worth spelling out.

Receiver sensitivity figures for these three standards are not measured the same way, so putting them in a column next to each other produces a comparison that means nothing.

• P25 sensitivity is typically quoted per TIA-102 CAAA, in dBm at a stated bit error rate.
• DMR sensitivity is typically quoted per the ETSI method, and vendors often publish it in microvolts rather than dBm, at both 5 percent and 1 percent BER.
• TETRA publishes two different numbers, and the difference between them is large.

That last point deserves its own paragraph. TETRA datasheets quote both a static and a dynamic sensitivity. Static sensitivity is measured with the signal fed by cable, free of multipath. Dynamic sensitivity is measured under a faded, multipath channel of the kind a moving user actually experiences.

The Motorola Solutions MXP7000 datasheet is a clear worked example, because it publishes all four figures:

Comparing like with like, guaranteed against guaranteed and typical against typical, the gap is exactly 9 dB in both cases. Note how easy it is to get this wrong: set the typical static figure of −118 dBm against the guaranteed dynamic figure of −107 dBm and you produce an 11 dB gap that compares two different things, which is the same category of error as comparing across standards.

If you set a TETRA radio’s static figure against a P25 radio’s TIA figure, TETRA looks competitive. If you use its dynamic figure, it looks far worse. Neither comparison is valid, because the two numbers answer different questions. For mobile or portable operation in a multipath environment, the dynamic figure is the more representative of the two, and the reason it is published at all is that TETRA’s standards work addressed the faded case explicitly.

The practical rule is to compare like with like or not at all. Compare radios within a standard on their published figures, and compare across standards only through a coverage prediction that applies each system’s own fade margin, or through a field trial.

Choosing

Strip away the vendor material and the decision usually resolves on four questions.

Do you have to interoperate with government or public safety? If yes, the answer is P25 and the other two are not really candidates. Interoperability was the entire design goal, and in Australia that is what the networks you would be joining actually run.

Are you upgrading an existing analogue fleet on existing sites? DMR is the path of least resistance. It reuses the 12.5 kHz channel, its coverage is comparable to the analogue system it replaces, and you are unlikely to need new sites purely because of the technology change.

Do you need integrated data, telephony and dense trunked features as first class parts of the system? TETRA was built that way from the start rather than having them added later, and its four slot carrier gives the most voice paths per transmitter, which matters when RF plant space or combiner complexity is the binding constraint.

Where are your sites? As the licensing tables above show, this genuinely changes the arithmetic. High density sites reward the technology that uses the least spectrum. Remote sites reward the technology that needs the fewest spectrum accesses. Those are not the same technology.

And one point that belongs on the list: P25 Phase 1 is hard to justify for a new system on cost grounds alone. It uses twice the carrier bandwidth per conversation of the other options here, it needs roughly twice the transmit spectrum accesses, and the annual tax follows accordingly. It remains the right answer where interoperating with an existing Phase 1 network requires it, and in practice that is frequently the deciding factor.

Practical Rules

• Size the traffic before choosing the technology. The number of simultaneous traffic paths you need is an Erlang problem and it is independent of the standard. Settle it first, then map it onto carriers.
• Count carriers and spectrum accesses, not channels. The carrier count drives transmitters, combining and rack space. The access count, which is two per duplex carrier, drives the licence bill. Neither follows from the traffic path count alone.
• Price the annual tax over the system life, not just the purchase. A forty thousand dollar a year difference dwarfs most differences in equipment pricing over ten years.
• Establish the density area before comparing technologies on cost. The ranking changes between high density and remote.
• Do not compare sensitivity figures across standards. Compare within a standard, or compare through a coverage prediction that applies each system’s own fade margin.
• Ask which TETRA sensitivity figure you are being quoted. Static and dynamic can differ by around 10 dB on the same radio.
• Treat P25 Phase 1 as an interoperability decision rather than a technology decision. If nothing forces it, Phase 2 carries the same traffic in half the spectrum.

Frequently Asked Questions

Which is better, P25, DMR or TETRA? None of them, in the abstract. P25 is the answer when you must interoperate with government and public safety networks, which in Australia is what those networks run. DMR is the answer for commercial and industrial fleets upgrading from analogue on existing sites. TETRA is the answer when you want a trunked network with data and telephony built in and you value the fewest RF carriers per voice path.

Is TETRA more spectrally efficient than DMR? On the nominal calculation they are equal. Both deliver one voice path per 6.25 kHz of carrier bandwidth: DMR by splitting a 12.5 kHz carrier into two slots, TETRA by splitting a 25 kHz carrier into four. Real world efficiency depends on overheads, control channel capacity and frequency reuse, which differ. In practice TETRA can occupy slightly more paired spectrum for the same number of traffic paths, because its 25 kHz carrier granularity rounds up in larger steps.

Why does P25 Phase 1 cost so much more to licence? Because it is FDMA and carries one voice path per 12.5 kHz carrier, where every alternative carries two or four. Twenty traffic paths needs 21 carriers on Phase 1 against 11 on Phase 2, and the ACMA taxes every transmit spectrum access annually. Counting both duplex directions, that is 42 accesses against 22, or about $86,622 a year against $45,373 in a high density area under the model used in this article.

Does DMR have worse coverage than analogue? Not inherently. DMR keeps the same 12.5 kHz channelisation and the standard describes its 4FSK modulation as constant envelope, so an existing analogue system can often be converted on its existing sites. That is a favourable starting point rather than a guarantee, and actual coverage still has to be verified from the radio performance, the propagation environment and the digital reliability required.

What is the difference between DMR Tier II and Tier III? Tier II is conventional DMR and Tier III is the trunked tier, with a control channel that assigns traffic channels on demand. The carrier and spectrum arithmetic in this article is Tier III, because that is what compares meaningfully against P25 trunked systems and TETRA.

Why do TETRA radios publish two sensitivity figures? Static sensitivity is measured without multipath, with the signal fed by cable. Dynamic sensitivity is measured under a faded multipath channel representing a moving user. The dynamic figure is worse, often by around 10 dB, and it is the more realistic predictor of field performance.

Can I mix these standards on one network? Not on one air interface. They are different physical layers and radios for one will not talk to another directly. Interworking is done at the network level through gateways, which adds cost, latency and a failure point, and is a reason to settle the standard question early rather than late.

Work the Numbers for Your Own System

Every carrier count, spectrum figure and licence cost in this article was computed rather than estimated. The LMR Trunked System Planner does the same job for your fleet: it builds offered traffic from your talkgroups, sizes the channel pool against an Erlang C access time or Erlang B blocking target, maps the result onto real RF carriers and paired spectrum for P25 Phase 1 and 2, DMR Tier III and TETRA, and compares the four technologies for the same channel requirement across a multi site network.

For the traffic sizing on its own, the Erlang B and Erlang C calculators solve the channel count directly. To check what is already assigned around a proposed site before committing to a frequency plan, the Frequency Coordination Tool runs the interference analysis against nearby licences.

Related reading: How Much Does a Radio Licence Cost in Australia? for the full fee calculation behind the licensing tables above, What Is Erlang? for the traffic sizing, and How to Get a Radio Licence in Australia for the licensing process itself.

Notes on Sources

• TIA-102 for P25, ETSI TS 102 361 for DMR, and ETSI EN 300 392 for TETRA are the governing standards, and the carrier, slot and control channel rules used above follow them.
• TETRA air interface figures were read from ETSI EN 300 392-2 V3.4.1 (2010-08). Clause 5 states that “for phase modulation the modulation scheme is π/4-shifted Differential Quaternary Phase Shift Keying (π/4-DQPSK) or π/8-shifted Differential 8 PSK (π/8-D8PSK)” and that “the modulation rate shall be 36 kbit/s for π/4-DQPSK and 54 kbit/s for π/8-D8PSK”. The same edition also defines 4-QAM, 16-QAM and 64-QAM multi sub-carrier modes, so π/4-DQPSK is the original phase modulation rather than the only one TETRA defines. On frame structure it states that “four timeslots shall form a TDMA frame” with a frame duration of 170/3 ms, approximately 56.67 ms. The 7.2 kbit/s figure is the net rate of the TCH/7,2 traffic channel; the full rate ACELP codec itself is specified in EN 300 395-2, which was not consulted.
• DMR air interface figures were read from ETSI TS 102 361-1 V2.5.1 (2017-10). It describes “the constant-envelope modulation, entitled 4FSK”, sending “4 800 symbols/s with each symbol conveying 2 bits of information”, with a timeslot “length of 30 ms” numbered “1” or “2”. Its own definition of TDMA direct mode is an operation “that supports two transmissions per 12,5 kHz frequency”, noted as supporting “6,25 kHz equivalent (6,25e) spectral efficiency”. The word equivalent is the standard’s own, and it is the reason this article treats the 6.25 kHz figure as nominal.
• P25 modulation and vocoder details are deliberately not stated in this article. The TIA-102 suite is not publicly available, so those figures could not be verified against the source, and nothing in the analysis above depends on them.
• Carrier, spectrum and control channel arithmetic was computed with our own LMR trunked planning engine, which encodes the rules above. Licence figures apply two chargeable transmit spectrum accesses per duplex carrier, as set out in the model paragraph above.
• Licence figures were computed from the ACMA apparatus licence fee schedule, edition 2026-07, and exclude GST. They are calculations from the published rates rather than a quote, and the ACMA’s assessment of an individual licence is the authoritative one.
• NSW Public Safety Network details, including its use of P25, its former name and the 67 percent current and 85 percent target land coverage figures, are from the NSW Telco Authority.
• Receiver sensitivity figures for the static and dynamic comparison are the published guaranteed and typical values from the Motorola Solutions MXP7000 data sheet (© 2025 Motorola Solutions, dated 12-2025).

Standards are revised and networks are expanded. Check the current edition of any standard and the current state of any network before relying on a figure here for a design.