[HN Gopher] Introduction to open source private LTE and 5G networks
___________________________________________________________________
Introduction to open source private LTE and 5G networks
Author : peter_d_sherman
Score : 576 points
Date : 2021-07-25 05:28 UTC (1 days ago)
(HTM) web link (ubuntu.com)
(TXT) w3m dump (ubuntu.com)
| nixpulvis wrote:
| I'm a little confused about how UE authentication works with open
| source cellular. Are there re-programmable SIMs that you need to
| buy? Or it only works with virtual SIM cards written in software
| on non-commercial equipment.
|
| To ask simply; could I expect to easily connect my iPhone to one
| of these networks?
| bserge wrote:
| Yes, programmable SIM cards.
|
| https://www.smartjac.biz/mobile-telecom/sim-cards/4g-lte-sim...
|
| Buy pre-programmed or invest in a programmer + a bunch of
| blanks.
| toomuchtodo wrote:
| Does this work with eSIMs?
| g_p wrote:
| Unfortunately not - eSim is a fairly closed-shop ecosystem.
| You can't easily type in the provisioning parameters into a
| QR code generator and get an eSim to use.
|
| You need to work with a GSMA-approved eSim issuer who has a
| special CA-signed certificate to authorise a handshake via
| some cellular standard protocols to do the eSim setup
| process. This process does prevent keying material being
| exchanged in plaintext, but also "locks in" the need for an
| intermediary in the process unfortunately.
|
| So while you could make eSims, you'd need to work with a
| GSMA-approved issuer.
| grishka wrote:
| That's unfortunate. Is it possible bypass this
| restriction on a rooted Android phone, or is it
| implemented in hardware?
| lxgr wrote:
| As far as I know, eSIMs are usually implemented in
| physical hardware, close to (or maybe even on) the
| baseband, but independent from the baseband firmware.
|
| This is because they are considered a trusted execution
| environment; if they weren't, it would be possible to
| "clone" eSIM instances.
| grishka wrote:
| Ah, right. "Trusted" in the modern dystopian sense that I
| physically own the thing but it's controlled by someone
| else.
| g_p wrote:
| Exactly. The whole baseband in your phone is considered
| "trusted" by the network because you can't easily control
| it. Don't give the carriers ideas - if they thought they
| could move to a "ma Bell" style of you leasing the phone
| from them without ever gaining ownership rights of it,
| someone would try to! Look at carrier locking, and the
| world of CDMA, where your phone has to have its ESN
| (serial number) manually whitelisted to join the
| network... It's a whole different world from general
| purpose computing!
|
| The mobile standards are built around the assumption that
| the baseband does as it's told by the network - your
| phone's transmit slots get scheduled by the base station,
| and your phone sits quietly until those slots to speak.
| This extends to the wider architecture and design of the
| ecosystem - the user is not "meant" to be in charge of
| their device in the mobile ecosystem. With the split
| between AP and CP (application processor and cellular
| processor), if you put the CP on a suitable bus like USB
| which doesn't give DMA access, you can build a phone you
| have sufficient control of (see Pinephone etc).
|
| In the world of SIM, this is back to carrier thinking -
| they control the SIM as it's "theirs". The keys on the
| SIM are known only to them, not even to you. You're not
| trusted to know your own SIM authentication parameters.
| This can be helpful in some ways, as it makes the threat
| model different to other systems and you can't
| unwittingly disclose your keys to someone through social
| engineering... But it's less helpful as customers
| generally don't think like security architects who
| designed this, and end up just having their physical SIM
| stolen, or their carrier ports their number after social
| engineering...
| grishka wrote:
| Where I'm from, phones were always decoupled from
| carriers. The carrier sells you a SIM card, that's it.
| It's on you to buy or already have a compatible phone to
| stick it into. I don't think any of the big carriers ever
| offered financing as part of the contract the way US ones
| do. Also we only have prepaid plans.
|
| It's a shame still that you can't have a 100% open-source
| phone. I'm the kind of person who believes that all of
| the humanity's knowledge must be freely accessible to
| everyone. Including schematics and documentation for
| every device ever made, including ICs. It's
| counterproductive when multiple companies have to
| reinvent the same thing... and then keep it secret like
| the others.
| grkvlt wrote:
| not exactly modern, or dystopian - see also paper money,
| for instance, which may be owned by you, but is
| controlled by another entity and contains features making
| it hard to modify or duplicate.
|
| the analogy is flimsy, i suppose (paper thin, lol?) but
| the problem is that the user cannot be trusted to be non-
| malicious. however, with esim technology i had assumed
| the trust was assured using keys owned by the proivider,
| so i'm not sure whether there's something else going on
| here?
| grishka wrote:
| Money is only valuable because the society makes it so,
| and especially because governments only accept taxes in
| their own currency. But if you own a banknote, it's fully
| yours. You can spend it on anything -- including
| something illegal like drugs. Or you can draw something
| on it thus invalidating its value. The government that
| issued it doesn't have a say in any of this.
|
| But with modern locked-down electronics, you could only
| do what the manufacturer intends, and nothing more.
| Continuing with monetary analogies, it's like a credit
| card that only works for things your bank considers
| "good" for you.
| bserge wrote:
| Afaik, it has little to do with the user-facing software,
| you need access to the baseband modem part.
| varispeed wrote:
| Do you know why is this a closed shop? Is there a legal
| reason or whichever corporation controls it ensured that
| they have a monopoly? Is there a way to open this up?
| g_p wrote:
| From memory, I believe GSMA (the industry association
| that helps to keep mobile technology dominated by
| carriers that hold exclusively licensed spectrum, if
| you're cynical) require everyone who provides eSim to
| have been security audited. They can then get access to a
| trusted certificate that will be able to sign the
| handshake to the embedded security module (eSim).
|
| It's complex, but remember that in the traditional world
| view of mobile, the carrier "owns" the SIM, and the
| handset, and the network itself. When the carrier can't
| control the SIM in its entirety, you need to have someone
| brokering the relationship here between everyone -
| otherwise a carrier coming onto a device may lack
| confidence the device isn't compromised by the previous
| network that served it.
|
| Some information that might help you start look around
| the topic - https://pages.arm.com/rs/312-SAX-488/images/G
| SMA_eSIM_Certif...
| lxgr wrote:
| eSIM implementations need to be closed because they are
| considered a secure execution environment for loading
| eSIM profiles (in that it should not be possible to
| extract the keys contained in a profile).
|
| I'm not actually sure if there is a good reason for the
| eSIM profile server (called SM-DP+ in the language of the
| specs) to be part of the same trusted computing base;
| maybe defense in depth against a malicious profile/SAT
| applet trying to access the data of others on the same
| eSIM?
| bserge wrote:
| You don't need hardware for that. Just need to be able to
| program your own carrier profile... which I guess is very
| hard to impossible for the average person.
| lxgr wrote:
| What do you mean by "carrier profile"? An eSIM profile?
| mnd999 wrote:
| This would be super useful if it could me made to work on
| the secondary eSIM for iDevices.
| [deleted]
| X-Cubed wrote:
| I'm not sure about 4G, but certainly with some of the earlier
| variants it was relatively easy to make your local DIY network
| visible as 'foreign' roaming network to your phone with it's
| normal SIM.
| akulbe wrote:
| Can someone educate me as to a/the use case for this?
|
| Does this mean you are providing cell service to others? or is
| there another purpose for it?
| rswail wrote:
| It's a mechanism to use 5G protocols for a localized WAN, not
| anything to do with phone carriers.
| rullopat wrote:
| I remember a customer in Italy that in the warehouse didn't have
| a good enough reception, so he to install a 3G repeater inside to
| be able to use the phone. After a few weeks, financial police
| arrived to his place, ordered to shutdown everything and fined
| him in 5 digits Euro.
| mychele wrote:
| This is a list of open source tools to do this
| https://open5g.info/
|
| Something important that may be overlooked in the blog post is
| that for most bands you need licenses to transmit over the air.
| ISM bands are unlicensed but may come with other limitations
| (e.g., in some countries regulators require a listen-before-talk
| mechanism that is not always implemented in cellular stacks).
| punnerud wrote:
| All the examples in the blogpost is areas where you own the
| property, and in most countries can deploy this if you are
| careful not to interfere with areas outside of your property.
| With 5G this is easier because you can use ISM bands within the
| "core" and WiFi closer to the edge.
| ng55QPSK wrote:
| in case you are interested: In germany (DE) the regulator offers
| 5G (actually technology neutral) offers local, campus licenses at
| a very low price:
| https://www.bundesnetzagentur.de/DE/Sachgebiete/Telekommunik...
|
| 1 year, 10MHz, 1km2 residential-> 1300EUR
| orblivion wrote:
| Interesting. Why don't mesh networking projects switch to this?
| rckoepke wrote:
| See also RENEW, the "world's first fully programmable and open-
| source Massive-MIMO Platform" which may help to provide open
| source hardware and firmware for high-end installations.
| https://news.ycombinator.com/item?id=24026416
| eplanit wrote:
| This could get interesting at defcon conferences (if they're
| still a thing), which is already famous for having the world's
| most hostile wifi networks. Now DIY, private stingray?
| vsskanth wrote:
| How does one go about getting access in the US to use a frequency
| that can cover a large area per access point?
|
| I've worked in remote mines before which heavily use telemetry
| and they all seem to be on 2.4 ghz mesh networks. IIRC they need
| an access point every half a mile or less and are expensive to
| maintain.
|
| If you could install just one tower in a mine in the office and
| have the entire area covered, it would be a game changer.
| bradstimpson wrote:
| CBRS (3.55-3.7GHz) has been available for over a year now in
| the US. I've worked with a few mines that are deploying it to
| get a larger coverage area than WiFi. You should start by
| speaking with one of the SAS vendors, e.g. Federated Wireless.
| devops000 wrote:
| Do you need a different SIM to connect to a private network or
| you can use a commercial one (Verizon etc..)?
| pgorczak wrote:
| LTE and 5G use something like pre-shared keys for both user and
| operator so no to the second option in most cases except
| emergency use (you can make emergency calls via any network).
| [deleted]
| mcv wrote:
| This is not new to 5G. I believe it was HAR2009 that ran its own
| GSM network. Not sure if it included 3G, but probably not. So use
| was limited, but still cool that it was possible.
| seba_dos1 wrote:
| CCC events have ran 2G infra for ages, and since recently there
| was also 3G and 4G. There were even workshops where you could
| operate a femtocell.
| stevejb wrote:
| I have been thinking about how to do a deployment on a farm,
| using a private 5G network for some sensors and security cameras.
| I looked at LoraWann but it didn't have the bandwidth for
| cameras. Would something like this work?
| landemva wrote:
| "Mobile networks are much more secure than WiFi."
|
| Would like to see this claim substantiated. TLS protocol runs the
| same on either pipe.
| g_p wrote:
| The threat posture of both networks is quite different. As a
| user, as you rightly point out, TLS means it doesn't matter to
| you much!
|
| But if you turn it around and thinks about the problem as a
| business user, where you have some ancient legacy systems that
| can't do TLS, you can set up a private APN for authorised
| users, and connect that APN over a VPN or dedicated private
| leased line to the insecure service. The mobile network itself
| has a different set of security assumptions that make this
| possible.
|
| Client isolation by default prevents other devices from probing
| your device like they can on a wrongly configured wireless LAN.
|
| The authentication keys to join the network cannot be stolen by
| a compromised phone or phone firmware. An authorized user can't
| let another unauthorized user access the network using
| credential sharing. Swapping SIM into another device can be
| detected and the join attempt rejected.
|
| Long term authentication secrets sit in hardware protected
| storage in the SIM and core network - radios and base stations
| never see long term key material. If you join a roaming
| network, key material remains secure and the roaming network
| gets scoped keys that only work on their roaming network.
|
| That's not to say any of this is impossible to do with radius
| and other systems like 802.1x, but it's the default in
| cellular. As an end user though, TLS is most probably good
| enough for you, as you say. Put your DNS over TLS and if in
| doubt use a VPN. A cellular network will offer you much more
| protection against ARP spoofing by another client device peer,
| a sensible modern system won't be bothered by this. It's a
| different threat model and perspective where cellular is more
| secure - as an individual you might not be too bothered.
| vlovich123 wrote:
| That's an interesting claim though considering mobile network
| standards have for the longest time had (intentionally) weak
| crypto and anyone could spoof being a provider (eg stingray).
| I'm sure wifi has its flaws but "user could potentially
| misconfigure a network" is different from "this network has
| one or more intentional back doors but it's configured
| correctly other than that"
| rawrmaan wrote:
| Also check out the open source work of Helium and FreedomFi, who
| are working to help individuals easily deploy 5G/LTE offload for
| major carriers and get paid for data usage.
|
| https://freedomfi.com/helium5g/
| glitchc wrote:
| Please don't do this. Not only is this a violation of the
| agreement between you and the ISP, but consumer internet pipes
| were never designed for this type of service. This is only
| feasible if the internet coming to your house is a business
| line, which it won't be if you live in a residential area.
| przemub wrote:
| I'm surprised by how downvoted you are. It is kind of obvious
| that it is a violation to me here, since we have a history of
| people reselling their bandwith in blocks of flats.
| glitchc wrote:
| People feel entitled to their internet access without
| consideration of infrastructure costs, especially in North
| America. They see symmetric multi-GB connections commonly
| offered in countries such as Japan, South Korea and
| Singapore, and wonder why it can't be done in the US.
|
| Population density is why: Singapore is ~8400 people per
| square kilometre, while the US is a scant 36 per square km.
| That's two orders of magnitude difference. Everything else
| follows from this (high prices, single provider, spotty
| last mile service, etc.)
| Nextgrid wrote:
| > People feel entitled to their internet access without
| consideration of infrastructure costs, especially in
| North America.
|
| What? People are paying the infrastructure costs through
| their internet bill. If the ISP is pricing it wrong or is
| mis-representing what they're selling then it's the ISP's
| fault and not the customers'. The ISP is free to change
| prices and/or change their marketing to represent the
| true nature and capability of the service they're
| selling.
| PeterisP wrote:
| Population density is often used as an excuse for this,
| but it's a weak excuse.
|
| Finland has less population density than USA and manages
| to solve these issues; NYC has more density than
| Singapore and still has the same problems with internet
| access and pricing as the less dense areas of USA.
|
| No, it's not about the population density, the key
| difference is in the lack of competition.
| icedchai wrote:
| This is true, but even in US locations with high
| population density, we _still_ don 't have symmetric
| multi gig connections. Instead, we 1 or 2 choices for a
| wired ISP: generally cable / DOCSIS and DSL. And around
| here, PSTN copper is literally rotting on the poles, so
| DSL is out. Fiber is supposed to be installed "soon" (I
| estimated 1 to 2 years.)
| KingMachiavelli wrote:
| If I pay for unlimited data at XMbps, I expect to be able to
| use as much data as I want. If I cannot then ISPs should
| advertise more honestly.
|
| Plus, I'd be very surprised in Comcast Business was actually
| using separate infrastructure.
| mnd999 wrote:
| ISPs should advertise more honestly, but if they started
| talking about contention ratios in their advertising the
| average consumer would rapidly lose interest.
|
| With business, it's not separate infrastructure necessarily
| but the number of customers sharing the same infrastructure
| is significantly lower. This leads to more consistent
| speeds and less congestion.
|
| Edit: fuck you downvoters - this is comment is both
| accurate and helpful.
| goodpoint wrote:
| > the average consumer would rapidly lose interest.
|
| On the contrary, in a lot of places most consumers
| complain about misleading claims about speed and capping.
|
| The average consumer understands that daily rates for a
| hotel room change based on season, day of the week,
| special events and room size.
|
| Paying variable data rates based on usage and guaranteed
| bandwidth is not more difficult.
| varispeed wrote:
| > ISPs should advertise more honestly, but if they
| started talking about contention ratios in their
| advertising the average consumer would rapidly lose
| interest.
|
| In short, they have to lie to get business? Why is that
| even legal?
| jacoblambda wrote:
| It's not though. Sure what you say may be correct in some
| amount but it has little to do with the comment you
| responded to and isn't much more than excuse for why ISPs
| take advantage of their (largely) monopoly powers in the
| residential internet space.
|
| The reason you don't get a consistent speed and a
| guarantee as a residential ISP client isn't because of
| any of the reasons you mentioned. It's because ISPs can
| force you to pay for their service at whatever price they
| charge and no matter how bad it is.
|
| The internet could be out for 8 hours a day, you could
| get sub-dialup speeds consistently, you simply can't
| connect to some services for some inexplicable reason, or
| your packet loss could be so bad that you get kicked from
| services and pages constantly. Guess what, you are still
| going to pay for it because what's the alternative? No
| internet at all or satellite internet that goes out
| whenever a cloud is in the sky and that alots you 1GB a
| month at 56kbps for 200USD/month.
|
| No matter what a residential ISP does, they will still
| get their money and even if you service is complete trash
| you'll grin and bare it lest you end up without access at
| all. That's the reason we don't get consistent service
| with residential plans and it won't change until
| something happens to break us out of the monopolistic
| regulatory captured environment we are in.
| mnd999 wrote:
| Yes, the US residential market would definitely benefit
| from more competition.
|
| The model we have here is to separate the infrastructure
| from the service such that infrastructure providers lay
| fibre to homes and businesses and then sell wholesale to
| ISPs who sell service over the common fibre to consumers.
| It's definitely better than the US model as there is
| competition between ISPs and they therefore have reason
| to apply pressure to get problems fixed. Infrastructure
| upgrades are still painfully slow as there is little
| competitive reason to upgrade the fibre (or fibre /
| copper VDSL in many places) as all the ISPs have little
| choice but use the infra provider for a certain area.
|
| Ideally you want more infra, but the cost of building out
| fibre networks is high, particularly if you're only
| selling to 1-in-2 or 1-in-3 properties due to
| competition. That's before you get to the politics and
| legals and lobbying you need to do to succeed in the US.
| I'm hopeful 5G will compete with broadband and give the
| providers the kick up the ass they need.
| echelon wrote:
| Your license probably doesn't have a provision for
| subletting.
| Nextgrid wrote:
| Does screen-sharing and letting someone control your
| screen count as "subletting"? Does inviting someone to
| join your local Minecraft game (which internally starts a
| server and exposes it to the internet) count as
| subletting?
|
| If your ISP sells you a service of X Mbps (and if they
| want to be more precise, X packets per second and X total
| data transferred in a month) you should be able to use it
| for any purpose you want. The purpose or content of said
| packet don't suddenly make it take more network
| resources.
|
| If ISP's networks suddenly can't cope because people
| start using what they've paid for then it's on them and
| they need to price it accordingly and market it more
| honestly.
| gjs278 wrote:
| im going to do it
| rhexs wrote:
| Wow, letting anyone use my network as a back haul in exchange
| for a cryptocurrency I've never heard of.
|
| Sign me up.
| [deleted]
| hoppyhoppy2 wrote:
| On a related note, the Pine64 folks are working on the PineDio,
| which will use LoRa https://wiki.pine64.org/wiki/Pinedio
| goodpoint wrote:
| LoRa is incredibly slow at scale due to the _shared_ spectrum
| and extremely asymmetrical. Also entirely proprietary and
| patented.
| e2le wrote:
| There will also soon be a LoRa addon board (backpanel) for the
| PinePhone that'll be powered by an ATtiny84! A working port of
| meshtastic for this device would be very interesting.
|
| https://wiki.pine64.org/images/b/bc/Pinephone_LoRa_BackPanel...
| peter_d_sherman wrote:
| Related:
|
| OpenLTE (Wikipedia)
|
| https://en.wikipedia.org/wiki/OpenLTE
|
| OpenLTE (Technical Page, SourceForge)
|
| http://openlte.sourceforge.net/
|
| SourceForge OpenLTE Wiki, installing:
|
| https://sourceforge.net/p/openlte/wiki/Installing%20OpenLTE/
|
| "FPGA Implementation of LTE Downlink Transceiver with
| Synchronization and Equalization":
|
| https://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.69...
|
| EETimes, "Implementing LTE on FPGAs":
|
| https://www.eetimes.com/implementing-lte-on-fpgas/#
|
| Also interesting is doing a Google query with "FPGA" and "LTE"
| and/or "OpenLTE" as the search parameters:
|
| https://www.google.com/search?q=FPGA+and+%28LTE+or+OpenLTE%2...
|
| (Also note that GNU Radio: (https://www.gnuradio.org/about/) and
| SDR:(https://en.wikipedia.org/wiki/Software-defined_radio) -- are
| related topics that may contain some overlapping areas of
| interest...)
| boramalper wrote:
| And also OpenRAN: "The OpenRAN Project Group is an initiative
| to define and build 2G, 3G, 4G, and 5G RAN solutions based on
| general-purpose vendor-neutral hardware, open interfaces and
| software."
|
| https://telecominfraproject.com/openran/
| peter_d_sherman wrote:
| Excellent link!
|
| Also, for those that are new to the "RAN" terminology (as I
| was just a few minutes ago! <g>):
|
| https://en.wikipedia.org/wiki/Radio_access_network
| smokelegend wrote:
| Are these part of WAN's[Wide Area Network]....?
|
| A RAN is mini-WAN?
| philprx wrote:
| I would say Yes in terms of size: usually most of RANs
| are nationwide.
|
| But No in term of type: RAN is a functional part of
| operator operational network and therefore not as
| function and traffic neutral as a WAN is.
| pomatic wrote:
| I'd love to setup a small scale network for personal use, but the
| elephant in the room is licensing.... Is it actually possible to
| formally license a DIY LTE network? (Or AMPS, 2G, 3G). In the UK,
| for example it is possible to get experimental licenses in
| principle, but I doubt it would be possible for an individual to
| legally operate a permanent or long term network on/near
| commercially allocated frequencies?
| ffk wrote:
| Check out CBRS which is "licensed-by-rule." You should be able
| to use CBRS to deploy private 5G.
| alexfromapex wrote:
| I think there needs to be a push to make it possible. It's kind
| of tiring having big corporations being the only ones who can
| do things.
| karteum wrote:
| There are already a lot of things that are feasible without
| any license. In Europe/CEPT, you might have a look at all
| bands under the provisions of ERC Recommendation 70-03
| (https://docdb.cept.org/download/2464).
|
| However, those provisions are made in order to ensure a
| good/fair access to anyone, and therefore to prevent a single
| user or single technology from overusing those bands which
| are meant to be shared. For that purpose, there are
| associated restrictions (in terms of power/EIRP, duty-cycle)
| and/or mandatory sharing approaches (Listen-before-talk,
| detect-and-avoid, etc.). In the case of Wi-Fi, CSMA/CA is a
| form of listen-before-talk.
|
| Unfortunately, mobile technologies defined at 3GPP (GSM,
| HSPA, LTE, NR) are not designed to be used in such a way
| (i.e. they don't have any sharing mechanism such as LBT and
| they require _by design_ dedicated/licensed bands), which by
| the way implies some kind of specific coordination at the
| country borders where two operators are using the same
| channels... (you might look at ECC recommendation 15-01 for
| an example of PCI sharing).
|
| LAA is a way to have an LTE carrier within the (shared) 5 GHz
| band, but it has to rely on an anchor carrier for signaling,
| which requires licensed spectrum. Multefire is a fully-
| unlicensed solution, but I doubt many UEs (smartphones)
| support it, and anyway because it must implement the same
| power limitations and LBT as wi-fi in order to comply with
| regulations I doubt it would be much better than wi-fi...
| (maybe it would in some specific case where deterministic QoS
| is important)
|
| One more thing : keep in mind that a typical 3G/4G/5G
| macrocell site (e.g. around 65 dBm EIRP per carrier) is
| something very expensive : your mileage may vary but it can
| easily be around 100000 EUR / site when some construction is
| required.
| joecool1029 wrote:
| >LAA is a way to have an LTE carrier within the (shared) 5
| GHz band, but it has to rely on an anchor carrier for
| signaling, which requires licensed spectrum.
|
| I want to add, as I said in my last comment that 5G NR
| allows for 5Ghz to be used as primary carrier, it was
| controversially included in the standard. A study from
| earlier this month showed LAA apparently doesn't play too
| well with wifi nearby:
| https://www.cs.uchicago.edu/news/article/laa-wifi/
| g_p wrote:
| In general, cellular technologies have been designed
| against assumptions of a clean (or at least exclusively
| used) RF channel. 4G and 5G are deployed with frequency
| reuse between base stations, which implement the same
| standard and can coordinate their emissions and
| scheduling of clients (both in time and frequency) to
| minimise interference.
|
| WiFi is a whole different kettle of fish - it's designed
| to be used by multiple independent access point operators
| simultaneously, with the ability to change frequency if
| needed based on the interference observed. It's designed
| to try to deliver good performance by listening before
| transmitting etc, to avoid transmitting over another
| device, to avoid a tragedy of the commons scenario where
| selfish devices end up rendering WiFi unusable for
| everyone (including themselves), through refusing to
| yield time to devices transmitting on other networks.
|
| NR-U and LAA etc don't generally play according to the
| same rules, as they're standards arising from the world
| of exclusive spectrum access, and coordination of base
| stations by one operator - in the world of cellular, the
| base stations allocate uplink channels for their clients.
| That doesn't work in WiFi with multiple networks in the
| same approximate location, hence they need to try to
| prevent interference and cross-talk.
| TaylorAlexander wrote:
| If anyone knows the answers to this for USA I'd be very curious
| (at this time I don't see one). People are mentioning possibly
| using a 5ghz band?
|
| Very weird that the ubuntu article talks about how easy it is
| to do this and makes no mention of spectrum license concerns.
| joecool1029 wrote:
| 5G NR allows for 5Ghz to be used as primary carrier in band 46.
| (as opposed to LTE that only allows it as a secondary carrier.)
| This wouldn't require a license to use.
|
| I believe CBRS band 48 (3.5Ghz) is lightly licensed but I don't
| remember if you can set it up as a primary carrier on LTE.
| ksec wrote:
| Do you know how does the patent licensing works on 5G NR-U? I
| have been trying to find an answer but literally everyone in
| the industry are mum about it.
|
| I really really want to see real world usage of NR-U and as a
| possible replacement of WiFi.
| g_p wrote:
| I understand that NR-U is a full implementation of a 5G
| base station (and client handset/CPE if you can find one
| that actually implements NR-U!), and therefore you will
| require patent licenses for the full implemented stack.
|
| In an ideal world, your radio manufacturer and software
| vendors would have appropriate patent licenses in place.
|
| For this and other reasons (handset support being
| commercially problematic since carriers want to preserve
| their dominance), I don't see NR-U really replacing Wi-Fi.
| The friction to joining a device to a network is also far
| higher, and there's much more complexity in running the
| network and architecting a suitable core network and user
| plane functions and keeping it all running. WiFi really is
| a lot simpler in many ways.
| ksec wrote:
| Well NR-U is pretty much a Qualcomm technology (
| MultiFire ) brought to 3GPP for standardisation. So I
| expect it to be supported in all 3GPP Rel 16 modem and
| Qualcomm X60+ modem as well. I dont think Handset support
| would be a concern unless I am missing something.
|
| I was hoping for some exemption or special arrangement on
| the patent issues for consumer private 5G Network. WiFI
| just sucks, comparatively speaking. Including WiFI 6E.
| And judging from the ways they are doing things I have
| very little hope for 802.11ay and 802.11be ( WiFi 7 ).
| socraticmethod wrote:
| >WiFi Sucks...Including 6E
|
| Outta curiosity, why do you say 6E sucks?
| karteum wrote:
| CBRS is very US-specific...
|
| It is indeed an innovative way to give access to spectrum,
| but it's a pity it has been done in this band (which had a
| huge potential for usual operators in terms of site reuse).
|
| I suspect in Europe a light licensing approach such as CBRS
| might be considered in higher bands such as 26 GHz...
| g_p wrote:
| In the UK there are 2 ways to get access to long-term spectrum.
| It's also usable from a bands and handets perspective!
|
| 1. Shared access licence. There's 3.3 MHz (duplex paired) of
| former DECT guardband available for local use at the top of the
| 1800 MHz band. This should work fine to run 2G or 4G. There's
| 10 MHz of TDD at 2390 to 2400 MHz, indoor use only I believe,
| and most useful for 4G. There's also 3.8 to 4.2 GHz which
| allows outdoor use, and is dedicated shared spectrum for 5G.
| Transmit power limited aren't enough to run a big commercial
| network, but are enough to deploy a private network on a campus
| or private site.
|
| The former two should be widely supported on handsets. The
| latter (5G option) is aligned with band N77.
|
| 2. If you're in a rural area, get a local access licence to
| "take" existing operator spectrum and use it legally, with 3
| years max tenure. It can be renewed if the operator has no
| intention to use it. Operators don't like this, as they see
| spectrum as their owned property, but this isn't the case, and
| they only have a right to use it...
|
| The process of getting a local access licence is deliberately
| complicated by operators as they don't want you doing it, but
| it can be done. You need to understand the technology and
| commercials of the industry though to realistically be
| successful. Some operators want you to talk to them first,
| others want you to talk to Ofcom first. If you know what you're
| doing, and make a strategically selected request for spectrum,
| it can be done. You can operate a commercial service in this
| spectrum, but you have to be clear to users the time-limited
| nature of spectrum access.
|
| Going forward though, it's clear from Ofcom's own priorities
| that a more dynamic nature of spectrum allocation and
| utilisation authorisation is a priority and likely to be coming
| down the line - it's been a work item the last couple of years.
| Once that comes, we could see easier ways to access spectrum.
| Realistically though, operators will do what they can to make
| spectrum access complex, to preserve a final moat in a market
| of 10+ years of continued reduction in average revenue per
| user.
| ackbar03 wrote:
| What would be the cost of this though? I thought these things
| tend to get bid up to the range of billions of dollars
| g_p wrote:
| These licenses are in set-aside bands specifically for
| sharing. You're talking about 80 GBP per year for up to 10
| MHz, and 80 GBP per year for each additional 10 MHz.
|
| https://www.ofcom.org.uk/manage-your-
| licence/radiocommunicat...
|
| This isn't nationally auctioned spectrum (which gets bid up
| to billions, then operators have to pay those fees into
| government coffers).
| ackbar03 wrote:
| Whoa!!!! That is not expensive! I did not know that
| numpad0 wrote:
| At least on paper the Japanese sXGP standard is close to what
| you want, it's reportedly just TD-LTE Band 39 and equipments
| are licensed the same way as Wi-Fi APs and dongles are.
|
| Maybe if there's enough demand for workplace private phone
| network, such laws could be passed to run 5G or 4G as Wi-Fi
| alternatives.
| vxNsr wrote:
| Yes this was my question... The FCC is pretty aggressive about
| keeping people off frequencies they don't have a license for,
| how does that work in these types of environments? Especially
| something like a college campus, where you have 10,000+
| students who would all need their phones to be reprovisioned...
| not to mention how would it work if you walk off campus? LTE/5G
| isn't really great at working with multiple networks... it just
| wasn't set up that way...
| varispeed wrote:
| Does it mean that the protocol has big corporation monopoly
| built in by design? I am not familiar with the details, but
| by the sound of it why is this even legal?
| vxNsr wrote:
| Not really, anyone can own spectrum, in the last few years
| its gotten really expensive as it's become more important
| to building a robust network but historically it wasn't
| that hard to license an small band in your area.
| PeterisP wrote:
| Radio spectrum is a shared resource that for many use cases
| needs exclusive allocation to work well - if one
| person/organization is using a frequency band in an area,
| they need to be the _only_ ones who can use that frequency
| band there. Think TV or radio stations; if someone else is
| transmitting in the same channel, then it just disrupts the
| broadcast. So most such spectrum is allocated (often
| through auction) and then whoever has that allocation is
| legally granted a monopoly on the use of that spectrum,
| enforced by government who will prevent anyone else from
| using that spectrum with fines and even physical
| interference (finding, disconnecting and confiscating the
| violating transmitters) if needed.
|
| Transmitting over radio waves is a highly regulated
| privilege. There are a few ranges that are open to public
| (i.e. the bands used for Wifi and BT) with devices that
| need to be certified to ensure that they transmit only in
| the narrow permitted ranges, but in most frequency ranges
| (including the LTE/5G ranges) it is illegal to operate a
| transmitter without an explicit license.
| edrxty wrote:
| This was true decades ago but for the vast majority of
| modern applications users would be just fine sharing
| spectrum and dynamically negotiating/avoiding each other.
| If you go look at an SDR waterfall you'll find that
| vanishingly little spectrum is ever in use but almost all
| of it is reserved for various interests, mostly using
| legacy analog modes.
|
| We need more and wider unlicensed bands, there's no
| reason for most of this regulation anymore.
| Sephr wrote:
| You could simply host your network on unlicensed spectrum.
| dsr_ wrote:
| AFAICT -- and I would be happy to see counter-evidence -- all
| the unlicensed spectrum suitable for LTE or 5G is in the 5-6
| GHz frequencies. The physical characteristics of transmission
| don't change, so one might as well just deploy the cheaply
| available 5GHz wifi systems -- you don't get an advantage by
| using LTE or 5G protocols.
|
| i suppose if you only had relatively low data rate
| applications you could use 900MHz, but there's a dearth of
| CPE. 900MHz unlicensed has slightly more bandwidth than a
| single 2.4GHz wifi channel.
| dilyevsky wrote:
| You can probably drop it down some more and use tvws
| spectrum. Probably will be alone there
| g_p wrote:
| TVWS channel allocations often don't align neatly with
| duplex paired 3GPP bands, meaning you might need multiple
| adjacent TVWS channels.
|
| In addition, in many countries the TVWS regulations only
| cover specifically authorised devices which adhere to
| TVWS standards (which 3GPP doesn't), and create a whole
| host of challenges for the client devices (handsets),
| which don't understand TVWS rules, and need their
| transmit power to be controlled by the base station,
| which isn't necessarily aware of the client location, or
| authorised within TVWS rules to query the TVWS database
| on behalf of the client.
| cozzyd wrote:
| Might as well use 8.0211ah there. It's not like you can get
| consumer equipment that supports the 900 MHz ISM band for
| LTE.
| pgorczak wrote:
| Rules are different in each country of course but most
| unlicensed frequencies can only be used with mechanisms that
| leave space for other users (networks) like listen before
| talk or restricted duty cycles. Cellular technology isn't
| built with shared access to spectrum in mind although there
| is/was some effort to add it (LTE-U, 5G-NR-U).
| cozzyd wrote:
| I recently deployed an LTE network at a research station in
| Greenland. Licensing ended up much easier than I expected (the
| Greenlandic government almost immediately granted the license
| for LTE band 8), but this is in a place in the middle of the
| ice sheet hundreds of miles from the nearest village.
| ackbar03 wrote:
| Did you have to pay for the lisence? Don't these lisence
| normally cost something in the range of billions of dollars?
| cozzyd wrote:
| No. I suspect if it was in a region people lived in and we
| weren't using it for research purposes, we may have had to
| pay, though I doubt it would cost anywhere near that order
| of magnitude in Greenland...
| gregsadetsky wrote:
| I'd love to hear more about this, if you can share.
|
| How complex / large is it of an installation? How comparable
| (or not at all) to setting up a large scale wifi network? How
| complex is the maintenance? Team size for installing /
| operating vs number of people served?
|
| Everyone's phone has a custom sim card?
|
| Thanks :) Truly curious about this.
| cozzyd wrote:
| Just one eNodeB (the "Radio Access Network," i.e. part that
| connects to the antennas, sourced from Star Solutions), two
| antennas (13 dBi sectorial antennas with spatial
| diversity), and an EPC (the "backend," also from Star
| Solutions) as a VM on a single server. The goal is serve a
| detector array of 35 indepedent detectors up to 10 km away
| from the base station (which is mounted on the roof of the
| tallest building in the research station, some pictures of
| both a station and the base station that I happened to have
| taken are available here: https://www.desy.de/news/news_sea
| rch/index_eng.html?openDire... ). Each station has an omni
| 8 dBi LTE antenna mounted at several meters height. I also
| did put a sim card in my phone and it worked fine though
| that was not the primary purpose (but it allowed me to
| video call from the middle of the ice sheet far away from
| the station WiFi, which was kind of a novelty).
|
| The only feasible alternative was 900 MHz WiFi which would
| have been similar, but lower throughput and much less
| available technology, whereas LTE modems are cheap and
| abundant.
|
| It was deployed about a month ago and so far so good. It's
| data only, and the server the EPC is on just acts as a
| gateway.
|
| Due to the conditions, the eNB is indoors. Installation of
| antennas was done by station carpenters as I was not
| allowed on the roof without training :). I am a physicist,
| not a telecom engineer but it was not too complicated.
| gregsadetsky wrote:
| Really fascinating. Thanks a lot for this description!
| g_p wrote:
| Not OP you replied to, but have done similar before.
| Answering your questions in order (at least the ones not
| specific to that scenario) to share some thoughts, which
| are certainly not answers by any stretch:
|
| - setting up a mobile network is quite different to a WiFi
| network in some ways, but perhaps a little more in line
| with a complex large-scale WiFi network. Mobile networks
| are architected around a "core network" which manages
| mobility and user traffic, and a "radio access network"
| which connects the base stations to your core network. The
| "core" is a fair bit more involved than a large-scale WiFi
| network setup, at least in my experience. You will need
| domain knowledge of 3GPP networks, and that's sometimes
| hard to get hold of, at least outside of traditional mobile
| operators and vendors. That can be a barrier.
|
| - In terms of maintenance, a well-built RAN should "run
| itself" for the most-part. You'll want some monitoring on
| equipment. If you are using modern software-based base
| stations, they will run on Linux. Treat this like any large
| at-scale fleet deployment of Linux servers. Keep them
| patched and plan your maintenance windows for reboots etc.
| Your core network itself will realistically be a bunch of
| Linux servers to provide network functions. You'll have the
| usual periodic maintenance issues keeping up a bunch of
| complex services that you don't always fully understand,
| and the temptation to never update anything, as "it's
| working right now".
|
| - The number of people you need for installing depends on
| skill sets. You'll need some experienced riggers to install
| macro sites on masts by climbing the masts. But you also
| need people who can pour concrete to get masts into the
| ground. And people who can install masts. You'll need
| someone who knows some DC electricals and can get
| everything powered up. You'll need some radio knowledge to
| plan out the network and check the antennas are pointed in
| the right directions and with the correct tilts. If you
| outsource this to a subcontractor, they can probably get
| the same people who do commercial networks to do it, but
| that will cost you dearly, and you'll never quite know what
| happened or how to fix it if something goes wrong!
|
| - To operate the network I guess it's not a huge amount
| different to any other complex IT system. If you build out
| your core network well, you can serve a few thousand users
| without too much trouble, with minimal people. Once you
| start to scale beyond a few thousand users, you have to
| scale up the core and architect it a bit better. There's
| some routine monitoring and maintenance, and the usual
| things you need to do in any production environment, but in
| general it's not too horrendous. If you go down the "big
| vendor box" route like carriers do, they'll take big
| complex managed services to keep everything in check, but
| have far fewer really good network people on-staff. The
| biggest issue you'll have in terms of staffing up to manage
| it is getting the breadth of knowledge and skills needed to
| have access to the right range of skills as needed - legacy
| telecoms can get complex fast. If you are having an issue
| with IMS for 4G calling (VoLTE), you might only need 1
| person, but that's in addition to the 1 3GPP core expert
| you have, the 1 IP networking expert you have, etc.
|
| - You need to put a custom SIM into every device, and set
| up a PLMN identity for the network, which is just a 5 or 6
| digit number that identifies the network to handsets. The
| SIM tells the phone what network it should try to join, and
| contains the crypto keys used to do authentication with the
| network. You can often get a PLMN allocated by your
| national telecoms regulator, or use one in the 999/xx
| range, which are set aside for private, uncoordinated use.
| gregsadetsky wrote:
| Truly grateful, thanks a lot for all of this insight.
|
| I have recurring daydreams of booting up a fiber ISP or
| WISP or (thanks to this post) a micro cell network, but
| peeking at the real-world implementation of those is a
| good way to remind myself that there's a ton of
| complexity that I shouldn't underestimate :-) i.e. it
| helps to keep those dreams "grounded".
|
| I've built temporary 500-people ethernet + wifi networks
| and I'm always curious to read what it's like to do it at
| a larger scale. Thanks again!
| jsjohnst wrote:
| > I've built temporary 500-people ethernet + wifi
| networks and I'm always curious to read what it's like to
| do it at a larger scale.
|
| If you've done this, you could do the WISP / private LTE
| network. Will you likely need to do a lot of research and
| reading? Yes. Will you occasionally make potentially
| costly mistakes? Yes. But will you be successful if
| persistent? Yes!
|
| As someone who owned a small WISP back in the earlier
| days of the Internet when finding guides was hard to do
| and has done a private 3G network for fun, it's
| definitely doable if you set your mind to it.
| gregsadetsky wrote:
| Thanks for the encouragement, I really appreciate it.
| g_p wrote:
| Don't force your dreams like this to be grounded!
|
| There is complexity in this, but remember here you're
| talking to people who chose to get deep down into the
| tech in every component out of a desire to learn, do it
| themselves, and save money!
|
| What I didn't mention was I built and ran that network
| effectively by myself (modulo mast climbing), with
| support of a few others who wanted to learn the ropes.
|
| A fibre ISP is absolutely achievable and there's been a
| few posts about those on HN recently. Depending on how
| you go about it, it's absolutely feasible to build out
| your own fibre GPON network. Heck I know people doing
| this who have absolutely no background in networking, but
| have learned the practical skills of splicing and hired
| in the networking knowledge to support them.
|
| A WISP is a bit simpler to get going than a cellular
| network, but you can also build one using cellular (that
| costs more). The big issue WISPs encounter is scaling
| their business and customer base up - it's easy to do
| lots of little point to point links in "customer
| obsessed" mode where you set out infrastructure to reach
| each rural customer. It's far harder to deliver a great
| service to these customers, especially as you start to
| distribute service from these points to multiple
| customers. A lot of WISPs end up with pretty messy flat
| networks they can't then scale up, and can't easily
| augment with fixed fibre to give themselves more
| capacity.
|
| You absolutely can start your own ISP or WISP. I won't go
| so far as to say you should, because to evaluate "should"
| you'd need to understand the local offerings and
| competitors and regulatory landscape, but it's definitely
| possible. In the UK, I believe from memory that something
| like 2 in every 3 kilometres of fibre to the premises has
| been laid by "non traditional" providers or new entrants,
| independent of the big telcos.
|
| Your own cellular operator is not impossible, but the
| scale you need to get to before you have a sellable
| product is the issue. You need to be (or use) a fibre ISP
| to get backhaul in. You need to understand site leasing
| and access arrangements. You'll need to be able to do
| radio planning and get spectrum access. You'll need
| billing and customer support and fault resolution.
| Managed services can help, but you'll rapidly see your
| revenues drain that way.
|
| In the US there are a number of smaller state-level
| cellular operators, who effectively do all this
| themselves. I wouldn't recommend trying to run a mini
| mobile operator as a business just yet until the
| supporting ecosystems get better able to serve smaller
| scale customers though - the rise of private networks
| will change this, but everyone is still thinking of
| national scale for now.
| gregsadetsky wrote:
| Really grateful for your answers and encouragement.
|
| For context, I'm in Canada where the ISP competitive
| landscape is dire. In the province of Quebec where I am,
| there are "debates" as to who should manage the
| government-installed electricity poles and be allowed to
| run any cable on them.
|
| Actually, it's the main national telecom giant who ended
| up managing those poles... Many small towns' high speed
| (i.e. dsl) projects are stalled because of this.
|
| I'll stay on the lookout for an opportunity. :) Thanks
| g_p wrote:
| If you are trying to do something about it, get some
| people together and look at the UK's approach to this -
| it sounds like you could bring a lot of this to Quebec.
|
| Not saying it would be easy - these sound like deeply
| entrenched problems to resolve - but often showing
| precedent for how it's done better elsewhere can help
| spur Commonwealth governments on.
|
| In the UK, you would want to point them towards the
| Access to Infrastructure regulations, and the regulator's
| approach to "duct and pole access" -
| https://www.ofcom.org.uk/about-ofcom/latest/media/media-
| rele...
|
| In the UK the "national telecoms giant" has to give
| equitable wholesale access to ducts and poles, and this
| is being used to lay fibre to the premises in rural and
| urban areas.
| aQutePsyOps wrote:
| https://www.ebay.com/itm/FULL-LTE-GSM-Network-IN-A-BOX-NIB-O...
| boba7 wrote:
| Shit is illegal in Europe. /thread
| detaro wrote:
| FTFY: Shit needs a license (or a proper lab environment) in
| Europe, like approximately everywhere in the world.
| varispeed wrote:
| > Shit needs a license, money, connections, bribes
|
| FTFY
|
| You can't just get a license if you don't know right people
| and you don't have suitcases of money ready to pass under the
| table.
| detaro wrote:
| Depends. Temporary, e.g. for an event, can often be done
| (although usually by operating under someone elses license,
| not getting one from scratch), with 5G there's likely some
| interest in femtocell setups where afaik some states are
| looking into special local licensing. But generally yes,
| difficult club to get into.
| beervirus wrote:
| We were talking about Europe, not China.
| sipos wrote:
| It isn't an under the table thing, at least in the UK. For
| the generalloy used frequency bands for this, there was an
| auction for the spectrum. You can get access to parts not
| being used by the people who bid on it.
|
| You can also get an amateur radio license, and use
| frequency not normally used for this, but that probably
| means using SDR as most devices designed to use LTE will
| only work on normal LTE bands etc.
|
| No bribes, connections, or anything shady etc needed.
| g_p wrote:
| There's also around 400 MHz of dedicated sharing-only
| spectrum in mobile bands, available in the UK at a flat
| price per 10 MHz required.
|
| (Replying to GP)
|
| At least in the UK, no bribes or envelopes of cash
| required. Nobody is going to want to help someone try to
| get started from scratch, but the spectrum access isn't
| anything like what you fear, at least in the UK. No
| connections required, the forms are all available online,
| and if you ask nicely and want bulk licences, you can use
| a spreadsheet instead for your requests, which is a bit
| less hassle than PDF forms.
| srinathkrishna wrote:
| I used to work on UMTS networks about a decade back and fresh out
| of college it was quite daunting. At that time I wanted to study
| an opensource implementation to gain more understanding but I
| couldn't find any. Glad to see this in the present time
___________________________________________________________________
(page generated 2021-07-26 23:02 UTC)