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Deputy Mayor / Adjoint au Maire

Network sharing explained!

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:Network-diagram.jpg

 

  • 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.

 

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)
  • 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/Discussions/Network-sharing-explained/td-p/129092/pag...

 

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

Great Citizen / Super Citoyen

Re: Network sharing basics

Cool, thanks for sharing that!

MVP
Model Citizen / Citoyen Modèle

Re: Network sharing basics

Thank you for  interesting info.

 

So, in case Public Mobile traffic is throttled/prioritized, by Telus, at which of the above units does it occur?

Oracle

Re: Network sharing basics

Great post I think this should be kept in teh knowledge base for future reference for those saying their coverage isn't as good now with PM


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Model Citizen / Citoyen Modèle

Re: Network sharing basics

Good stuff, thanks for sharing

Good Citizen / Bon Citoyen

Re: Network sharing basics

Can there not be any prioritization happening at the tower?

I think the main concern/question is the throttling happening for PM customers.

 

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

Re: Network sharing basics


@Indexx wrote:

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


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.

Mayor / Maire

Re: Network sharing basics

@sheytoon thanks for the detailed and yet easily understandable breakdown of how we get our services.  That was an enjoyable read!


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Great Citizen / Super Citoyen

Re: Network sharing basics

IF.....and I use the word IF strongly.

 

IF Telus is prioritizing Telus / Koodo / PM customers, then it would happen at the core network side (EPC).

It would not happen at the tower side as the agreements between Bell and Telus to share the towers equally.  FIFO (first in, first out) or first come first serve basis.  A Bell owned tower doesn't give priority to bell customers before Telus.  

 

ALSO, before switching my Telus number to PM, I ran a Telus sim and PM sim at the same time and did calls and speed tests all over Halifax, NS, Bedford, NS, and Dartmouth NS (my local areas) and it demonstrated equal service and speeds within a few kb/s of each other (resonable margin).  less than 25kb/s difference.

 

 

Deputy Mayor / Adjoint au Maire

Re: Network sharing basics

@MVP, @Indexx:
Prioritization can be done at RAN or core, but in different ways. RAN doesn't have a lot of granularity, so you could reserve a certain portion of spectrum for all Telus subscribers and no Bell subscribers. There is no way to distinguish a Telus subscriber from Koodo or PM. Having said that, Bell and Telus do not do this. Everything is dynamic based on usage and there is no discrimination at the RAN. The only exception is VoLTE and ViLTE, which are standardized protocols and need GBR (guaranteed bit rate) service. This is a form of QoS to ensure a quality VoLTE experience during congestion. But again, Telus and Bell VoLTE are treated equally by the RAN (they're just treated better than internet data). Regular data is always "best effort" or non-GBR.

The core has a lot more control over individual profiles. I'm not a core engineer so it's hard to know if/how something is being done at the core level.

From the RAN's point of view, there are 2 operators: Bell (302-610) and Telus (302-220). Creating a virtual operator using different APNs (PM or Koodo) is 100% under the control of the core network.