Network sharing explained!

[sheytoon]

Hi everyone, I have noticed that there is some misunderstanding about the network sharing between Bell and Telus. Hopefully this will help with some of the confusion. I've worked as a network engineer for operators and vendors and this is an area I am familiar with.

To begin with, let's start with a simple LTE network diagram:

• UE is the phone.
• E-UTRAN is the LTE radio access network, also known as RAN. In LTE, the RAN is only comprised of 1 element, this is the base station, also known as eNodeB. This is basically the "tower" that your phone talks to. In 3G networks, the RAN is made up of NodeB (tower) and RNC (controller).
• EPC is the LTE core network (proper name is Evolved Packet Core), and this equipment is hosted in a few secure facilities across Canada. Data between RAN and core is carried via "backhaul" or transport network (not shown here).

Bell and Telus only share the RAN across Canada. They share 3G and LTE RANs. In some cities (Vancouver), Telus owns the RAN, and Bell users are allowed to use it. In other cities (Toronto), it's the other way around. This allows Bell and Telus to spend less money building out a network, while both benefiting from it. In a city like Toronto, there are only 3 RAN operators: Rogers, Bell, Shaw (Freedom Mobile/Wind). Any other company that sells service is really using the RAN of those 3 companies.

Bell and Telus have independent EPC and IMS networks (IMS is used for VoLTE among other things). The core network is what authenticates user SIM cards, tracks usage and billing, completes calls, delivers text messages, and connects data sessions to the internet. All Bell and Telus eNodeBs in Canada are connected to both Bell and Telus cores.

To make a phone call, or send/receive text, or use data, the whole network must be functional. The RAN cannot deliver any services on its own, and the core cannot directly talk to a phone. So if any of these parts go down, the user will not have service.

If there is ever an outage that only affects Telus subscribers, it's probably due to the core. If there is an outage that affect Bell and Telus subscribers simultaneously, it's probably due to the RAN.

Coverage is 100% due to eNodeB. Therefore, if you have good coverage with Bell or Virigin Mobile, you will have identical coverage with Telus, Koodo, or PM. It can be possible for coverage to be different if Bell and Telus didn't share all bands. However, they currently share all bands except Band 30 (2.3 GHz, which is high frequency and doesn't impact coverage). Band 30 is only for Telus at the moment.

UPDATE

As a result of Bell's 2017 acquisition of MTS, the situation in Manitoba is complicated. In Winnipeg and Brandon, Telus operates a new independent RAN, separate from the shared Bell/Rogers RAN. Coverage between Bell and Telus is different in these markets as a result.

/UPDATE

For a good map of NodeB (3G) and eNodeB (LTE) locations, refer to this link:

https://www.ertyu.org/steven_nikkel/cancellsites.html

After clicking on a site, refer to BW (bandwidth), this may give a clue to the technology being used.

• 1.25 MHz is CDMA (old 2G network that is not used by modern phones) As of mid-2019, there is no longer any CDMA networks in operation in Canada.
• 4.15 MHz is Bell 3G
• 5 MHz can be 3G or LTE
• 10 MHz or higher is LTE

Here is a specific example of how it works in Quebec City:

https://productioncommunity.publicmobile.ca/t5/Get-Support/Network-sharing-explained/m-p/148276/high...

If you have any questions, I'll do my best to help answer them!

Update: additional LTE topics explained here:

http://productioncommunity.publicmobile.ca/t5/Discussions/LTE-network-fundamentals/td-p/130581

Update 2: key information from this article was used in a 2020 post by Inside Towers, without crediting the original article here. 

[sheytoon]

Looks like someone copied most of the original article!

https://insidetowers.com/cell-tower-news-wireless-network-sharing-canadian-style/

Imitation is the best form of flattery? 😆

[sheytoon]

Ok please keep us posted. When there's no SIM, your phone might connect to Rogers or Freedom.

Bell SIM and Telus SIM should behave the same.

[bluesys]

I have LTE disabled on the S8 as with LTE enabled calls dropped almost every time.
With the Telus sim and LTE disabled the S8 phone works acceptably over some parts of the property but commonly reports "no service" or drops calls at times inside the house.
With the Telus sim in the S8 it always connects to the cell tower east of Arnprior and reports very low signal levels in the range of -113~-119.
Calls drop, text messages often fail to send and arrive and most of the time data really does not work.
With the sim removed the S8 always connects to the stronger cell tower west of Arnprior and reports a acceptable 93~97 signal.
I understand the sim card's service provider should not matter but there is a lot of software at work here and so I wonder.
If the sim does not matter for tower selection it is unclear why emergency service always connects to a different tower with a stronger signal.
That seems a contradiction to the sim having no affect in tower selection. Perhaps the emergency service tower selection code uses completely different tower selection criteria.
As a past telcom designer I have personally experienced the "unintended" due to the miles and miles of code that no one person understands in modern products.

I am working on getting a Bell sim card working in the S8 and then see what tower we connect to. That may shed light on this puzzle.
If the S8 with a Bell sim connects to the stronger west tower I should be good as signals levels are always much better on the west tower.
If not and I still get the weaker east tower even with a Bell sim I will have learned something but not the puzzle as to why a no sim card phone always connects to a much stronger tower.
Going to take me a few days to get a Bell sim sorted out in the S8. Stay tuned.
Bob

[Jb456]

@bluesys  You can also go to Samsung Canada website and open a live chat with them for the unlock code.

[sheytoon]

Is it possible the other phone is on 3G and the S8 is on LTE? I think if there's no SIM, your S8 would use 3G only.

Unlocking is free, so you can always request it from Koodo and Bell to give it a try. On a Samsung phone, dial *#0011# to see details of which cell you are connected to.

[bluesys]

Thanks for taking the time to reply. This is a interesting puzzle.

I understand the tower hardware is shared on any given tower and so will result in the same signal levels if connecting to the same tower. I also understand there can be a large difference between and one phone even of the same model. My galaxy S8 is locked to Koodo so sticking in a Bell sim did not work. Sigh.

But I had a idea. Just pull the sim card and the phone should connect to the nearest tower from any service provider in "emergency mode". So I set up a experiment. I carefully marked with tape a spot on the kitchen counter so the phone position would be consistent and not affect results. I did not hold the phone in the test as I note your hand position can affect signal levels. With the sim card in place I used "Network Cell Info Lite" app to measure the signal level and to pinpoint the tower connected. With the Koodo sim in place the phone consistently connects to a weak signal (-107) tower east of Arnprior. When I remove the sim the same phone consistently connects to a stronger signal (-95) tower west of Arnprior.

Both towers are Bell band 5. These results are very repeatable.

It seems there may be a roll in service provider software in tower selection as I believe this test removed the other variables in tower selection and signal levels.

If there is a way I can attach screen shots showing the test results I will do so.

A puzzle indeed.

The next and finial test it seems I will need to have the phone unlocked and put in the Bell sim to see what tower we connect to.

Cheers.

[sheytoon]

@bluesys for a given cell, there is only one physical radio transceiver, and it's shared. Any perceived differences in signal levels are due to different phones. You can switch SIMs to verify this.

[bluesys]

I live outside the town of Arnprior in the Ottawa valley of eastern Ontario.

Cell service in this area is spotty due to the limited number of towers and the hilly land.

I wonder why if Bell and Telus share all radio towers that in my case my Telus contract phones consistently connects to a tower with lower signal levels in my area than my other phone with a Bell contract.

The two phone consistently connect to different towers with the result the Bell contract phone works fine but the Telus contract phone is unstable in my home with a very low signal level.

This I checked with "Network Cell Info Lite" app. on both phones and the two phones consistently connect to different towers.

Thinking it just a phone issue on checking my wife's Iphone I see the same issue on her Telus contract Iphone, she also consistently connects to the lower signal level tower with the result the iphone also does not work in our home.

So Telus contract phones are basically unusable in my home where the Bell contract phone works acceptably.

I add interest both our Telus phones worked fine until a little over a year ago when Telus announced a "service improvement" in our area. After that the two Telus phones did not really work any more in the house.

I wonder why this is the case? Could Telus and Bell have different tower selection criteria in their network software that can lead to reception differences in low signal area of rural Ontario.

My interest is to find a way for all my phones to work in our home.

This seems tricky as both Telus and Bell should be the same but are not at all in my case and our Telus service quality changed drastically over time.

[srlawren]

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@Limestone wrote:

FYI

Fixed problem by switching off LTE in Iphone settings and forcing into 3G . Works like a charm now ! Cheers and thanks for explaining how system works 😉

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@Limestone glad you got it sorted!  Out of curiosity, did you have it set to LTE-only previously?  If so, that would explain the sympoms also (sorry I didn't think of that possibility in my original reply).  Setting it to "Auto" or "LTE/3G/2G" or whatever Apple calls it (sorry, I'm an Android guy) should also have the desired result.

[Limestone]

FYI

Fixed problem by switching off LTE in Iphone settings and forcing into 3G . Works like a charm now ! Cheers and thanks for explaining how system works 😉

[srlawren]

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@Limestone wrote:

Thanks for the info ! 

I live on an Island south of Kingston ON and get good reception on my Bell cellphone . Just ported my Bell landline to PM and all phone calls to my PM go straight to voicemail . Can't make outgoing calls either . Texts work OK . When I drive to Kingston my PM cell phone works fine . IF Telus ( PM ) sharing same towers as Bell why no service at my house on PM but OK on Bell ?

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@Limestone a few thoughts:

- For incoming calls, porting from a landline can take several days, even a week or more.  And Bell are known for holding up ports until they have had a chance to talk to you and try to talk you out of leaving.  However...

- For outgoing calls, this is not at all related to your port.  Since texts are working and calling isn't, and the phone is compatible with Bell mobile network, it could be compatilbe, but might not be.  Did you get the phone from Bell, or bring your own phone?  If the latter, is it an overseas model?  While Telus and Bell do share network, PM doesn't offer VoLTE (Voice over LTE), whereas Bell does.  I'm just speculating it could be that your phone, if an overseas model, may lack one or both of the needed 850MHz and 1900MHz 3G (UMTS/W-CDMA) frequencies needed for calling with Public Mobile, yet still have at least one compatible LTE band.  Texting works over LTE as well as over 3G, and Bell offer VoLTE, so the sympoms fit, but this is only a theory.  If the phone is originally from Bell, then this theory is almost certainly wrong.  What is your brand and model of phone?

[Limestone]

Thanks for the info ! 

I live on an Island south of Kingston ON and get good reception on my Bell cellphone . Just ported my Bell landline to PM and all phone calls to my PM go straight to voicemail . Can't make outgoing calls either . Texts work OK . When I drive to Kingston my PM cell phone works fine . IF Telus ( PM ) sharing same towers as Bell why no service at my house on PM but OK on Bell ?

[oglat]

NICE!!!!

thanks for the post

[kav2001c]

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@kav2001c wrote:

*bumping

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[kav2001c]

*bumping

[yogi799]

wrong thread sorry, deleted

[yogi799]

wrong thread, sorry, removed

[kav2001c]

*bumping

[sheytoon]

I got lucky today and ran into a core engineer and asked him about this. As expected, there is no prioritization in the network between the different brands (QCI and ARP are the same). Only VoLTE and ViLTE are prioritized, which makes sense.

He did tell me about a special project that @Hmm seems to be alluding to. I can't discuss it in public, but it may be happening some time next year. It's not related to the sub brands, so it won't change what I've said above.

[sheytoon]

Next time I run into the core engineers, I'll ask them. 

Absolutely, I need to see evidence before I'm convinced. So far, I haven't seen any. By the way, what do you mean by prioritization exactly?

[Hmm]

Later next year, there'll be more information made public regarding network prioritization by the big 3.

From a technical perspective, I suggest you engage in some meetings and diaglogue with the engineers with any of the major carriersand attend their meetings. It seems you need a lot of convincing that network prioritization is real and not a myth. 

[sheytoon]

@Hmm

Sounds like you have a lot more info than the rest of us. Can you help me understand exactly how it works?

What are the ARP values for Telus vs Koodo vs Public Mobile subscribers?

Since Bell recently launched a new brand (Lucky Mobile), did they assign their own priorities without impacting Telus customers? Would Telus be ok with Bell assigning higher priorities to Lucky vs Koodo/PM? How would this even work in a city like Vancouver where Telus is the RAN owner? How would it work in Toronto where Bell is the RAN owner? How would it work in Saskatoon where SaskTel is the RAN owner?

Really looking forward to hearing some details.

[Hmm]

All the premium carriers participate in network prioritzation but most people probably won't notice it unless it adversely affects them or they'll dismiss it as a one off.  

[sheytoon]

@ceciw

Do you know which operators implement prioritization? What does prioritization mean exactly? Can you give some examples of how it would work? Are you referring to pre-emption or admission/congestion control? I'm very interested in getting details about this. From what I've seen in the RAN, there's nothing implemented to distinguish between any Bell or Telus subscribers. I am not sure about the core network, so that's why I'm asking.

[Michael77]

@ceciw,

Thanks for the information. Very interesting. 🙂

[ceciw]

@computergeek541 wrote:

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@Indexx wrote:

Where does prioritization/throttling happen, and can there be discrimination between providers happening at the tower?

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The carriers likely have the ability to prioritize any subcriber they see fit over another.  Whether they actually practice this to normal cusotmers during every-day use is a matter that they're not telling us about.

From what I'm reading, some cell phone companies do give priority access to certain customers under a protocal called Wireless Priority Service.  Some members of emercency response teams, government, and other essentially/critical services are given the ability to dial a code that forces the network to give the prioty user the next available slot on the network to place a call.  The document that I was looking at specifically only meantion 2G netowrk ability, so the information may be a bit out-of- date,  but clearly, some carriers do at least the ability to priotize voice calls.

At the time of the infromation at http://www.ic.gc.ca/eic/site/et-tdu.nsf/eng/h_wj00016.html , only Rogers 2g and MTS cdma networks were providing WPS services,  but that information was as of 2011.

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Wow, thanks the OP for sharing!

I worked in telco (wind/freedom, shaw, rogers and bell) in the management and data level. I can probably shed some light on the 'prioritization' subscribers mystery.  They can, and some do in fact prioritize the different type of subscribers. For example, business customers vs individual customers,  business accounts are definitely 'more important' due to liability concerns.  In terms of bandwidth and networking matters, I cannot say about the intricacy of how it works.  But I can tell you when a company 'merge' with another company, in this case with PM and Telus, it is not easy to just merge the two company/brand operations or transfer one to the other.  What they often do in terms of prioritization, they keep them separate, and build in the ability to assign different IMEI and SIM to link the hardware with the brand, and assign the type of subscribers accordingly, and the prioritization follows.  Regarding the signal towers, who owes the tower who has the power.  In Toronto for example, towers are mostly owned by Bell, Telus has their own but when Telus need to share Bell's towers... maybe networking wise they work the same, but the owner still has the upper hand, at least that's what I understood when I was seating in boardroom meetings during discussions on competition matters.  Having said that, there are regulations to control the sabotaging each other though. 

[sheytoon]

Hi @Bill1
You're absolutely correct! The towers are all Telus and they broadcast 302-220 and 302-610. So even though it's a Telus tower, it will transmit Telus + Bell signals. Your SIM will cause your phone to look for 302-610, and the tower will use that info to route/connect you to the Bell core network instead of the Telus core network.

[Bill1]

Hi Sheytoon. So what I understand :  I have a Bell phone  with à Bell sim card. It simply search the 302-610 Bell signal.  So, both Bell and Telus towers, broadcast both codes. That's why my phone says that it receives "Bell" signal.

I live in Beauce where it's Telus RAN.  Correct me if it's not right :  I understand that the signal I receive is 100% from Telus and they take  my call  and direct it to  the "Bell" core network. So, there is no Bell stuff in the tower and no Bell signal. The only job is to bring my call to the Bell CN. Is that  right ??? Big TY for the answer.

[jpar]

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@McBryen wrote:

Thanks Luddite!

What I was looking for is any confirmation on if Public Mobile has access to the 2600MHz band if using a Bell Tower?

I see Telus has coverage in my city, but I don't know what part of their map represents the 2600MHz LTE band. It may be that they are receiving full access through another LTE band from Bell. The public mobile map provides no distinction between the frequencies. 

The reason I ask this rather odd question is because I saw mentioned in posts that Telus does not operate on 2600MHz for Bell towers (in a few cases, that information may be dated now).

TL;DR - There are Bell towers operating on 2600MHz near my house. Is there any reason that my 'future' phone, that supports FDD-LTE B1/B3/B5/B7/B8, will not connect to this?

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I connect on 2600MHz Band 7 in St. John's, NL (Bell) with no trouble at all. Phone seems to prefer it when the signal is good .

[sheytoon]

Hi @McBryen
When Bell initially launched LTE B7, it wasn't shared with Telus. It has since been shared with Telus as of a few years ago. You won't have any issues.