[HN Gopher] SrsRAN: Open-Source 4G/5G
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SrsRAN: Open-Source 4G/5G
Author : gballan
Score : 184 points
Date : 2025-01-05 21:27 UTC (1 days ago)
(HTM) web link (github.com)
(TXT) w3m dump (github.com)
| miav wrote:
| 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.
| throw5959 wrote:
| 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?
| jauntywundrkind wrote:
| 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.
| cyberax wrote:
| > The availability of hardware seems semi moot, since afaik
| there's basically no way to get spectrum short of big
| national auctions.
|
| You can run 5G in the unlicensed spectrum. AWS can rent you
| hardware for it: https://aws.amazon.com/private5g/ - it's $5k
| a month per site. I know a plant that switched to that
| because they couldn't get WiFi to work reliably for them.
|
| But even if you want to run within the licensed spectrum,
| local licenses for a couple of bands are cheap. I was
| involved in setting up a private network in the licensed
| spectrum around 10 years ago (based on
| https://aviatnetworks.com/ ), and a local site spectrum
| license was something ridiculously small (in the range of a
| hundred dollars).
|
| It's expensive if you want to do it nation-wide.
| diggan wrote:
| 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.
| sdmike1 wrote:
| 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.
| bri3d wrote:
| 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.
| throwup238 wrote:
| If I remember correctly, all the documentation needed to
| implement a 5G radio approaches 10,000 pages. It's not only
| insanely long and complicated but there's a nasty path
| dependency with most of 4G which is why Intel and now Apple
| have such a hard time getting their radios to the finish
| line. Poaching a few Qualcomm or Broadcom employees with
| better salaries is one thing but without the cumulative
| expertise contained within the companies, it's almost
| impossible to bootstrap a new radio.
| ksec wrote:
| >No common wireless standards are open, No wireless standards
| are feasible to implement.
|
| What is definition of "Open" here?
|
| The current submission is entirely about Open Source 4G/5G.
| Fabrice Bellard on top of the crazy amount of other stuff he
| did also made a LTE/NR Base Station Software [1]. WiFi and
| Bluetooth are also "Open".
|
| >But the thing that's holding Apple up is purely legal IMO
|
| People constantly mistaken having an open standard regardless
| of patents and an useable product on the market. There is no
| reason why you cant have a software modem aka Icera that was
| acquired by Nvidia in the early 10s. And there are no modem
| monopoly by Qualcomm which is common misconception across all
| the threads on HN and wider internet. MediaTek, Samsung,
| Huawei, Spreadtrum and a few others have been shipping 4G /
| 5G Modem on the market for _years_.
|
| The only reason why Apple hasn't released a modem 6 years
| after they acquired the modem asset from Intel is because
| having a decent modem, performance / watt comparatively to
| what on market is Hard. Insanely hard. You have Telecoms from
| top 50 market each with slightly different hardware software
| spectrum combination and scenario along with different
| climate and terrains. It took Mediatek and Samsung years with
| lots of testing and real world usage at the lower end phone
| to gain valuable insight. Still not as good as Qualcomm but
| at least it gets to a point no one is complaining as much.
|
| [1] https://bellard.org/lte/
| bri3d wrote:
| > What is definition of "Open" here?
|
| Patent unencumbered in a way that someone could make a
| commercially viable implementation as a "small or midsized"
| company, as the parent post asked. Open Source proves my
| point - the issue is not implementation (note - I'm not
| claiming implementation isn't hard, it is - I certainly
| know from personal experience that it is and I would never
| claim to be able to personally build an energy efficient 4G
| or 5G modem, but I don't think that raw engineering
| horsepower is what's holding Apple/Intel/NVidia back here).
|
| > MediaTek, Samsung, Huawei, Spreadtrum and a few others
| have been shipping 4G / 5G Modem on the market for years.
|
| The CCP effectively told Qualcomm to get lost in 2015 and
| Taiwan settled an antitrust agreement between them and
| MediaTek in 2018, so MediaTek, Huawei, and
| Unisoc/Spreadtrum are not good examples here. I believe the
| South Korean government also intervened on behalf of
| Samsung. Actually, the list of modem vendors you list
| pretty much matches exactly the list of governments who
| prosecuted, fined, and settled with Qualcomm for antitrust.
| RF_Savage wrote:
| >Patent unencumbered in a way that someone could make a
| commercially viable implementation.
|
| Doesn't this exclude all modern cellular standards then?
| msh wrote:
| yes.
| monocasa wrote:
| Fabrice Bellard open sourced a 4G (LTE) base station.
|
| https://bellard.org/lte/
| vbitz wrote:
| It doesn't seam open source?
|
| > The LTE/NR eNodeB/gNodeB software is commercialized by
| Amarisoft.
|
| > A UE simulator is now available. It simulates hundreds of
| terminals sharing the same antenna. It uses the same hardware
| configuration as the LTE eNodeB.
|
| > An embebbed NB-IoT modem based on Amarisoft UE software.
| chupasaurus wrote:
| Yep, the word "source" never mentioned.
| doublepg23 wrote:
| I assume Fabrice Bellard will crack cold fusion as a side
| project some day.
| user_7832 wrote:
| 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.
| mschuster91 wrote:
| > 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...
| teleforce wrote:
| Official srsRAN project website:
|
| https://www.srslte.com/
| maxloh wrote:
| 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?
| wmf wrote:
| 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.
| femto wrote:
| srsRAN is both. It includes the source for user equipment in
| its "srsue" directory.
|
| Use cases are partly captured by the list of customers across
| the bottom of the srsRAN home page (https://www.srsran.com/).
| It's great for any company/research group smaller than a
| multinational base station manufacturer, at which size the
| big players don't want to talk to you.
| nine_k wrote:
| A few applications I could think of:
|
| - Testing of various kinds. You can get deep inside an OSS
| base station, inspect and debug things, but likely may not
| even look at the proprietary innards of a commercial BS.
|
| - Emergency connectivity when the backbone is broken, or did
| not exist. Most people would bring mobile phones anyway.
|
| - Study / teaching, like MINIX OS or trainer aircraft which
| you can take apart and inspect.
|
| - Maybe very small local cells to improve connectivity in
| difficult landscapes (mountains, skyscrapers, underground).
| vardump wrote:
| > look at the proprietary innards of a commercial BS.
|
| I was wondering a bit whether that means Base Station or
| perhaps something else...
| emilamlom wrote:
| > Maybe very small local cells to improve connectivity in
| difficult landscapes (mountains, skyscrapers, underground)
|
| Something like this would've been useful in a couple remote
| networks that I worked on. Internet was easy to get with
| some ubiquiti wifi routers and antennae. Getting cell
| reception was a pain in the ass that involved setting up a
| repeater in the one spot of the valley where reception was
| kinda okay. I haven't looked into the project too much, but
| I imagine I could set it up to connect to a telcom tower
| and handle the wireless backhaul similarly to how I did the
| wifi.
|
| Edit: An open implementation like this could lead to
| cheaper cells for large, concrete/metal buildings that
| typically have terrible reception.
| wmf wrote:
| Femtocell equipment exists; the real issue is whether any
| of your local carriers support it.
| 1oooqooq wrote:
| 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
| kurokawad wrote:
| 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.
| leidenfrost wrote:
| Why can't I create an ad hoc 4/5g network between phones?
|
| Genuine question.
|
| It looks so closed and complex compared to more traditional
| comms like wifi or even ethernet.
| femto wrote:
| The LTE protocol is asymmetric between towers (eNodeB) and
| phones (UE).
|
| You could build srsRAN and run a local eNodeB instance to
| form a local LTE network. Given that it has a radio that
| operates in the LTE bands, in theory you might be able to
| build srsRAN for a phone and run the necessary base station
| software (eNodeB and EPC) on a phone to form an "ad hoc"
| network. It wouldn't be truly ad hoc in that the network
| would still have a base station, just that it would be
| running on phone hardware. srsRAN wouldn't be running as an
| application, but would be replacing the firmware in the
| phone's LTE modem.
|
| Edit:
|
| Here is a paper by someone who has built an ad hoc LTE
| network.
|
| https://arxiv.org/pdf/1802.09262
|
| It does exactly the above: using srsRAN (which used to be
| called srsLTE) to run local base station software
| (eNodeB+EPC) to get around the asymmetry in the LTE
| protocol.
| bsder wrote:
| > Why can't I create an ad hoc 4/5g network between phones?
|
| Because billing.
|
| All the complexity in cellular can be traced back to making
| the system secure the whole way back to SIM cards because
| there is actual money at stake if the system gets cracked.
| throw5959 wrote:
| What about a "public good" mobile network without any
| billing, only fair QoS?
| friendzis wrote:
| There's limited bandwidth available in the space. 5G is
| "fast" compared to 4G because 4G effectively saturates
| terrestrial bandwidth available. Public, unauthenticated
| network would be too easily DDoSable.
| mytailorisrich wrote:
| The complexity is actually down to mobility. You can turn
| your phone on anywhere and it'll work. You can have a
| call/data session while travelling hundreds of miles and
| it'll work (usually).
| rusk wrote:
| What you suggest could be accomplished with mesh
| networking. GP is correct in saying the reasons are
| orthogonal to functional reasons. Phone systems have
| always been centralised like this. Billing is one aspect,
| but lawful surveillance is another.
| mytailorisrich wrote:
| With respect, if you think that mesh networking would
| have worked considering the scale and capacity needed,
| and relevant type of devices then I am afraid this is a
| case of not knowing what you don't know...
| throw5959 wrote:
| How do you solve cross talk in congested areas? Made
| worse by the fact that mesh networks have a significant
| communication overhead.
| rusk wrote:
| Cross talk takes place on PHY and by the time you get up
| to routing it's all been eliminated
| rusk wrote:
| I was using Mesh networking as an example. Obviously it
| can't handle heavy load or longer distances well, however
| it is much more efficient for local point to point.
|
| If you like, you can consider just plain old VOIP where
| the central entity is used for discovery but the actual
| call may then be routed p2p though not in VoLTE and its
| successors of course because the media plane is also
| centrally routed.
| pgorczak wrote:
| They are not entirely orthogonal. You need a central base
| station with scheduling, high dynamic range and power
| control to maximize performance in an OFDM system. In
| addition, most cells used to use frequency division
| multiplexing meaning that the base station and phones
| send and receive on different frequencies. So lack of
| point to point capabilities can at least in part be
| explained by the design goal of optimizing for throughput
| and user density.
| rusk wrote:
| You do if you want to route across a broader area which
| is a different use case to what we are talking about. Two
| phones right next to each other are routes through the
| BTS even though they could easily route directly to one
| another and that is for non functional reasons.
| kurokawad wrote:
| AFAIK cellular comms aren't designed to be ad hoc. They
| require base stations (whose placement is very studied) to
| build coverage "cells" (cellular). The network is
| responsible of delivering a QoS, it's not a best-effort
| like WiFi.
|
| However, if I'm not mistaken 5G has V2V comms (Vehicle to
| Vehicle) specifically designed for self-driving cars,
| drones and IoT and that is the most "ad hoc" it can get
| solarboii wrote:
| It's complexity is not completely unnecessary. Scale is a
| huge bitch.
|
| Networking between phones, without a common base station,
| is hard. Harder than WI-FI, because identity is managed
| centrally and the frecs in use require a license to name
| some "simple" problems. Cellular comms are not designed to
| handle this kind of scenario.
|
| There has been some work to add inter device connectivity
| lately, to support many interesting use cases. You can find
| more looking for "sidelink" or "PC5", but you will not find
| many phones that implement it.
|
| It seems to be mostly focused in vehicular use cases in V2V
| and V2X scenarios
| ianburrell wrote:
| Last time I looked is because the chipset makers haven't
| implemented LTE Direct. There were a handful of phones with
| LTE Direct that were oriented towards first responders.
|
| 5G also has a peer mode, and I'm trying to figure out if it
| can be implemented in userspace or has to be done in
| firmware.
|
| My idea is that peer mode would be useful for replacing
| walkie-talkie or mesh messaging like Meshtastic since
| everyone has a phone. The range is supposed to be around a
| mile.
| femto wrote:
| Complex: yes
|
| Proprietary, Closed Standards: no
|
| Here are all the 3GPP 4G/5G standards that govern cellular
| phone networks:
|
| https://www.3gpp.org/specifications-technologies
|
| Also look under the "Specifications" drop down menu at the
| top of the page. Every release is listed.
|
| These standards being freely available is why SRS were able
| to write srsRAN. There is nothing stopping others from doing
| so either, apart from the amount of information that has to
| be understood and digested.
|
| Edit: Apart from complexity the other potential barrier is
| patents, but that's not a technical barrier.
| advael wrote:
| While it's technically true that the specs are public, the
| implementation not being public is most of the issue being
| solved
| miki123211 wrote:
| Apart from complexity and patents, the other other barrier
| is licensing.
|
| Those technologies aren't terribly useful to use in your
| house like WiFi is, and even if they were, you need more
| government paperwork to do it. That means less hobbyist
| interest.
| kurokawad wrote:
| The 3GPP spec is "available", but the implementation in
| practice is closed. Stuff like the scheduler is what
| actually brings value to the company delivering a good
| service. Being closed, the interoperability of network
| components from different vendors is just impossible.
| That's the point of O-RAN Alliance.
| blacklion wrote:
| Patents equal proprietary.
| cedivad wrote:
| <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
| blacklion wrote:
| > After a NDA with NXP...
|
| It is better than NDA with Broadcom, but still...
| motrm wrote:
| 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?
| mateuszbuda wrote:
| 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 wrote:
| 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.
| fulafel wrote:
| Nitpick: in most places you need a license to do this with
| antennas (in some places temporary licenses aren't that hard
| to get for temporary/noncommercial use)
| mateuszbuda wrote:
| Do you have an idea what would be my external IP address? On
| my phone connected to a mobile network, I get assigned mobile
| IP address which is my external IP address. It's not attached
| to the SIM card because it changes when I reconnected. Is it
| handles by the BTS software? Do I get assigned an IP address
| and BTS communicates on my behalf using that address which
| comes from the mobile network operators pool?
| bluGill wrote:
| 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.
| solarboii wrote:
| 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.
| joecool1029 wrote:
| N41 isn't 2.4ghz. It's licensed 2.5ghz. You're thinking N46
| which is unlicensed 5ghz.
|
| LTE didn't allow for it to be used as primary carrier, but
| NR-SA I think does.
| markedathome wrote:
| This site[1] details setting up an LTE network, including
| programming a blank SIM.[2]
|
| [1] https://www.quantulum.co.uk/blog/private-lte-with-limesdr-
| an...
|
| [2] https://www.quantulum.co.uk/blog/private-lte-with-limesdr-
| an...
| solarboii wrote:
| 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
| :)
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(page generated 2025-01-06 23:02 UTC)