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SrsRAN: Open-Source 4G/5G

195 points| gballan | 1 year ago |github.com

65 comments

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mateuszbuda|1 year ago

Can I use this to run my own mobile network? Is there something like a blank SIM card which I could use for it? I don't need global coverage but is it possible to create my own BTS on a PC (with some antenna connected to it) and then have my own SIM card which I can insert into regular phone/device and have it connected to my BTS and connect to the Internet?

markus-k|1 year ago

Yes and yes, although in most parts of the world it won't be legal when done via antennas. You can buy blank SIM cards from vendors like Sysmocom, which are preprogrammed but "writable" SIM cards. The important part is knowing the private key that is used to authenticate end user devices.

Then you'll just need a decent SDR and it actually works fairly well for small test setups.

solarboii|1 year ago

Yes, is simple enough to get started if you have access to the required hardware. You might able to operate in the n41 band (2.4GHz, like wifi) even without a license.

Phones are nitpicky about network configuration (chippers, emergency calling and so on). I would recommend starting with a USB modem. Also setting your network PLMN to the 00101 (the testing one), as it usually gets preferencial treatment in UEs.

bluGill|1 year ago

The hard part will be legal. You will need permission to have a radio and that often means certification of the system along with right to use the frequencies phones use.

cedivad|1 year ago

<shill mode> you can run SRSRan on a small self contained SDR such as the Seeve board. Throughput is not going to be good as a custom stack as it's unoptimised, though.

https://rfnm.com/blog/introducing-seeve

motrm|1 year ago

It's incredible to see such capability on such a tiny board.

The LA9310 has incredible specs, too, what a beast.

Have you done anything with its Network Listening feature? I'm curious if that's frequency flexible or if it's limited to a specific handful of common bands.

How have you found the NXP SDK, is it reasonably decent to work with?

blacklion|1 year ago

> After a NDA with NXP...

It is better than NDA with Broadcom, but still...

miav|1 year ago

Could anyone more knowledgeable on the topic explain to what extent common wireless connectivity standards are open and feasible to implement for, say, a medium sized company? Apple has been working on a 5G modem for what feels like a billion years, but other standards seem to be more democratized.

jauntywundrkind|1 year ago

The availability of hardware seems semi moot, since afaik there's basically no way to get spectrum short of big national auctions.

But now that T-Mobile is renegging their promise & not going to meet the minimum deployment size they promised, they have been saying the FCC should find a way to sell by area some of that spectrum sitting dormant in such a wide wide % of America (personally I think it makes their bid invalid & they should forefeit their bid for such egregious dirty lying). https://www.lightreading.com/5g/t-mobile-relinquishes-mmwave...

I think some of the analog tv spectrum has some precedent for being sold per-area rather than nation wide, but I'm not sure how that's been going.

In terms of hardware, there's some fascinating stuff. Facebook's SuperCell large-tower project showed awesome scale out possibility for large towers. Their Terragraph effort is spun out, and seems to have some solid customers using their hardware. Meta spun off their EvenStar 5G system, which has a strong presence at Open compute now. https://www.opencompute.org/projects/evenstar-open-radio-uni...

But it's hard to tell how acquireable such a thing really is. There's plenty of existing nodes out there too. It is unclear to me though how acquireable such things really are- there not being an open market, since there's no usable spectrum feels like a conundrum for the market, even though these are extremely high volume amazingly integrated advanced wireless systems that you'd think would be visibly prolific.

user_7832|1 year ago

From my limited understanding, the issue for Apple et al isn’t making a 5g chip, it’s making the chip small, cheap, power efficient enough and capable of having “decent” reception. I’d imagine existing patents by Qualcomm certainly make it a bit more challenging on terms of available (design) options.

throw5959|1 year ago

What do you mean by implementing? Make your own radio chips, designed from the ground up? Or merely producing a networking device using chips from suppliers like Intel, TI, Broadcom, Qualcomm etc? Or the software side only?

sdmike1|1 year ago

Stuff for GSM/CDMA has been around for years, OpenBTS is the primary example. This is the first I've heard of anything more modern/complicated being implemented. From my understanding, a lot of the hard eng work is in the RF frontend and making it small/low power enough to fit in a phone for example. OpenBTS got around this by using existing SRDs for their RF frontend.

diggan|1 year ago

WiFi, Bluetooth and Zigbee has bunch of public specifications and knowledge about it to make it feasible. AFAIK, the specifications for 4G/5G is publicly available but extremely complex + you'd need licensing agreements, pay royalties, etc. So unless this imaginary company of yours have specialized expertise in all that, it seems unlikely to be feasible.

bri3d|1 year ago

The big problem is patents and copyright. No common wireless standards are open. No wireless standards are feasible to implement. Seriously. It's that bad. Certainly a modern 4G/5G standard is complex from a hardware standpoint to implement - the way you usually do these is using a very powerful embedded DSP, which is also not open (Qualcomm Hexagon is the most reverse-engineered of these if you want to understand what's going on). But the thing that's holding Apple up is purely legal IMO.

mschuster91|1 year ago

> Apple has been working on a 5G modem for what feels like a billion years, but other standards seem to be more democratized.

The main problem is the sheer age of mobile phone networks. A phone has to support everything from top-modern 5G down to 2G to be usable across the world, that's almost as much garbage that a baseband/modem FW/HW has to drag along as Intel has to with the x86 architecture.

And if that isn't complex enough, phones have to be able to deal with quirks of all kinds of misbehaving devices - RF is shared media after all, and there's devices not complying with the standard, the standards containing ambiguous or undefined behavior specs, completely third-party services blasting wholly incompatible signals around (e.g. DVB-T operates on frequencies in some countries that are used for phone service in other countries, and often on much much higher TX power than phone tower sites). If it can't handle that or, worse, disrupts other legitimate RF users, certification won't be possible.

But that experience in dealing with about 35 years worth of history is just one part of the secret sauce - that just makes the costs of entry for FOSS projects really huge (which is why all of these projects I'm aware of support only 4G and afterwards since that generation is the first one to throw away all the legacy garbage).

The other part of why there are so few vendors is patents, and there is a toooooon of patent holders for 5G [1], with the top holders being either Chinese or known for being excessively litigious (Qualcomm). And even assuming you manage to work out deals with all of the patent holders (because of course there is, to my knowledge at least, no "one stop shop" compared to say MPEG), you still have to get a design that fulfills your requirements for raw performance, can coexist peacefully with almost all other users of the RF spectrum to be power efficient at the same time. That is the main challenge for Apple IMHO - they have a lot of experience doing that with "classic" SoCs, but almost none for RF hardware, virtually all of that comes from external vendors.

[1] https://www.statista.com/statistics/1276457/leading-owners-o...

maxloh|1 year ago

Can someone explain the use case for this project?

Is it intended for device vendors creating phones and tablets or for telecom companies building their own infrastructures?

kurokawad|1 year ago

Cellular comms. are all complex, proprietary, closed standards by big telecoms companies. There are some projects trying to solve this: OpenRAN, OpenAirInterface, O-RAN Alliance.

This project tries to build an open solution following O-RAN standards for RAN software. It is targeting telecom. companies for their Radio Access Network (RAN). Their infrastructure is divided into the Core Network (like a simple internet network) and the Radio Access Network (base stations, antennas and all that stuff). Phones and tablets are User Equipment (UE), nothing to do with srsRAN.

wmf|1 year ago

This is the tower side (RAN) not the phone side (UE). It's not clear who the audience is. I assume it's equipment vendors since running a real carrier on USRPs seems janky.

1oooqooq|1 year ago

ccc camp et al always have a 3G tower built on the older version of this. I'm no radio person but it's awesome to get a conf sim card and hack away

solarboii|1 year ago

They abandoning the UE development was a very sad moment.

Their code base is so much nicer than other projects, and somewhat easy to match with the standards. I am very happy user :)

whydoineedthis|1 year ago

O-Ran, the closed source that begins with O for open naturally, is really terrifying in terms of spying on users and sharing data.

My personal tinfoil hat says the corporations started the 5G cancer rumors themselves to distract the public from the real terror of 5G that is ORan data sharing.

The tl;dr is any participant in Oran can put software directly on the antena and access your data directly with no need for it to go through a 3rd party like your cell provider. The cell providers charge for access to the antenna. This sidestep any potentially conflict with selling your data - by choosing a 5g cell phone, you have already opted in to your data being accessed. Creepy.