The Heat Death of 5G

Spend any time in wireless, or Technology in general, and the subject of 5G is almost certain to come up. We have written about it here (and here). The world is full of talk about fast 5G networks and all the incredible new things that 5G will unleash. A whole new Internet, they say.

Here at D2D, we like to think of ourselves as practical, nuts-and-bolts-and-antenna people. So for us, a lot of this 5G discussion strikes us a bit breathless. Yes, 5G is coming and data rates will improve, but we, the mobile industry, still have a lot of work to do. We could regale you with litanies of woe about roaming and hand-offs, or belabor the small cell backhaul density logjam. But perhaps the best example of roadblocks to 5G is much easier to grasp – Heat.

5G phones get hot. Really hot. Probably not hot enough to ignite your battery (probably), but enough to generate a definite burning sensation in your pants pockets. At Mobile World Congress in February, we spoke with an engineer from Sony who was demo’ing a phone (behind glass) that was clocking 1 Gbps speeds. Wow, fast. We asked the engineer why it was not going faster and he said “It overheats.” A good solid answer, from a nuts-and-bolts-and-antenna person. We will wager any amount that at next year’s show, no one on the floor will be as open about this problem.

The big improvement in data rates for 5G will only come with mmWave radios. This is a whole new spectrum band that allows for really high data rates (again, let’s set aside the whole densification issue for now). The trouble is that mmWave radios generate a lot of heat. To greatly oversimplify, mmWave frequencies are pretty close to microwave frequencies, as in the thing we use to reheat our lunches.

From some of our very recent industry conversations we know that the handset industry is using a tried-and-tested method for dealing with this problem – ignoring it and hoping it goes away. The whole issue strikes us as one of those issues where middle management really does not want to raise the subject with senior management who have wrapped themselves so tightly around the 5G flagpole. “Uh boss, your pants are literally on fire.”

There are other factors at play as well. We will spare you our Deep State conspiracy theories on this (Buy us a beer in Barcelona…), but there is a pretty clear disconnect in the supply chain on this topic right now.

Of course there are some solutions, but none of them are complete and they all have serious drawbacks. It turns out that the way we cool electronics has not advanced in 40 years. There are really two methods used currently to cool Things down- Fans and Dissipation.

Fans are what you think they are. Anyone who has ever opened up their desktop PC or overclocked their laptop knows what these look like. But fans have two problems: they are big and they have moving parts. Both of those require design decisions that go counter to every mobile design trend in the past 15 years.

Dissipation is just the idea of moving the heat around to hasten air cooling. In a PC, this is typified by those funny looking prong-things that sit on top of CPUs. Those things are too tall to fit inside a 10mm thick phone. So for mobiles, OEMs are looking at using ‘straws’, or copper pipes that span the length of the phone. These take up a lot of space and inserting a large conductive element (copper!) inside a phone wreaks havoc on mobile radios, (i.e. hurting data rates).

Before we can revel in the Fullness That Is 5G, the industry needs to find a solution to this problem. And that will likely mean a whole new approach to the problem.

19 responses to “The Heat Death of 5G

    • I think that’s the standard industry reply. But the problem is much worse than with 3G. Anyone at your conference mention any figures? I’m hearing a heat budget that’s 67% higher than current phones. That’s a lot of watts to shed.
      And anyone have any ideas how they’re going to solve the problem? Solving the issue in 3G broke a couple vendors.

  1. Pingback: Start Up No.1,154: AI medical diagnosis as good as human, Amazon’s new IoT protocol, 5G’s heat problem, WeWork aims to sell three businesses, and more | The Overspill: when there's more that I want to say·

  2. What about the health hazards of the radiation from the towers which is present even if you dont own a 5G phone instrument? Was this discussed at the 5G conference?

  3. Pingback: The Heat Death of 5G - Papa Mar News Now·

  4. Pingback: 5G is Hot… Literally – ALLENDAV·

  5. Pingback: Links 9/28/19 – Breaking Worldwide News·

  6. Pingback: Links 9/28/19 – Viral News Connection·

  7. Wikipedia says consumer microwave ovens operate at 2.45 GHz. Wouldn’t a mmWave microwave oven only cook the outside of the food?

    • It’s not literally the same as a microwave oven. Different frequency, very different power profile. My point is just that invisible radio waves can cause a lot of heat.

  8. Pingback: Links 9/28/19 - News Views·

  9. AFAICT, 5G is primarily a way to pause the costs of laying fiber while propping up the stock price. By the time the average investor realizes 5G is a no-go, and how dreadful the conditions of networks have fallen, all the “backers” will be cashed out or retired.

    If solutions are found in the meantime that will make it actually possible, hurray. But I don’t see any valid actions or real intent to actually overcome the myriad of issues 5G faces.

    • That’s too cynical a take for me. 5G has some real benefits. But it’s going to take while to deploy. There’s a lot of complexity involved and that level of detail gets obscured by marketing/social media/stock market discussion.

  10. It is not that the use of mm waves which is generating heat, it is the high clock speeds of the transistors in the chips. Probably also some effect of transmitting such a high frequency. I suppose it will get fixed eventually.

    The related problem is battery life. The phones are hot because of the circuits which are powered by the battery. A hot phone means the battery is draining quickly.

    • Both of those are correct. The bigger issue though is that the heat is very concentrated around a small subset of device electronics, and there is no easy way to remove that heat.
      I think the battery life will be an issue, as it is with every new air interface generation, but one that the industry has a standard playbook for addressing.

  11. Pingback: Let’s Just Call it 6G | DIGITS to DOLLARS·

  12. Pingback: 5G’s Achilles Heel: Heat – loose wire blog·

  13. Pingback: Links October 2019 | Mato's Blog·

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s