AT&T on their LTE Backhaul Architecture

Backhaul is a topic that may be giving some operators nightmare. Picked up this slightly old article from Light reading via WirelessMoves.

AT&T network architect Yiannis Argyropoulos addressed the Backhaul Strategies and Core Convergence for Mobile Operators event in New York City and had the following to say:

The lines between wireless and wireline networks are blurring, as are the boundaries between access and core networks, driven by the need to carry the flood of wireless data traffic more efficiently. AT&T is aggressively deploying fiber to its mobile cell sites and migrating from Sonet to Ethernet, but more changes will be needed. AT&T started its fiber push in 2008, and it will take at least seven years to complete, said Argyropoulos.

For the short term, today's metro Ethernet architecture will support LTE, but longer term, the network architecture needs to have less operational complexity, noted the AT&T man. The carrier is in the process of testing new approaches, based in part on work being done by 3rd Generation Partnership Project (3GPP) and the Broadband Forum .

AT&T also is looking for coordination of policy control between its wireline and wireless networks, so that the core network services are the same for end-users, regardless of how they connect to the network. It is no longer adequate for quality-of-service to be delivered piecemeal, within different segments of the network, Argyropoulos stated: "There is a lot of work going on right now to harmonize these."

The early 3GPP scheme for QoS on 3G UMTS networks was too complicated to be implemented, but newer LTE QoS plans from the 3GPP, with nine QoS classes and a smaller number of individual class attributes, look more practical.




The growing volume of data traffic is having an impact on other areas of the carrier's operations, too. The widespread use of bandwidth-hungry smartphone devices is creating new traffic patterns that, among other things, eliminate traditional maintenance windows traditionally scheduled in the early hours of weekend mornings, Argyropoulos pointed out.

"Data traffic peaks at the same time as voice, but it has multiple peaks, and it doesn't ever really subside," he said. That, in turn, is putting pressure on wireless network operators and their vendors to do hitless network upgrades and to build more resiliency into their networks.

AT&T is looking to other means of offloading traffic, including routing optimization that will use gateways strategically placed in the network to direct traffic onto the Internet, and not carry it through the metro and core networks first.

"Most of the mobile data traffic is coming from the Internet and going to the Internet."

It will also be important to offload subscriber traffic generated in the home onto a domestic Internet connection, he added.

To get an Idea of the mobile backhaul load, see my earlier post here.

Along with Fiber, Microwave is also an option and you can read more about it in Daily Wireless blog.

Also came across this blod dedicated to mobile backhaul, that is available here.

How to avoid network choking in the future?

If you are looking for an answer to this question then you wont find an answer to that here. Probably no one really knows a complete answer to this question right now. A simple answer would be to have a mix of the Macro cells, Micro cells and Femtocells with some way to offload some more traffic via WiFi.

Earlier this month Skype announced that its client would be able to work on most Symbian phones. I have used the Skype client on phones from '3' and they work great. Skype is even available on iPhones and they were downloaded 1 million times in the first couple of days. Now a big chunk of operator profits come from long distance calls and calls when abroad. If we all start using our phones with Skype, its going to bite into the operators profits. That means they will have to recover this profit from us by another way.

Skype on phones will be used in always on mode, meaning that the networks will get loaded and get congested. A simple solution is to have Femtocells at home that can offload the traffic on Internet. These background apps do cause a considerable amount of traffic and recently an Operator blamed the apps for its network woes.

Femtocells have been targeted generally at the residential market with developments going on for Business users as well. Another smaller Picocells and Microcells are also easily and cheaply available nowadays. With the Ad-Hoc deployment of all these smaller cells, Self Organising Networks (SON) may have a big role to play.

What happens where there are multiple networks present in the same place via these smaller cells? Can the back-haul not get congested because of these multiple networks which may be lying Idle most of the time? How would these impact other services that we use on our PC's?

These questions can be easily answered if a single Microcell/Picocell/Femtocell was able to work for Multiple Networks. Practically this may not be possible right now because each network has a different Authentication and Security arrangement.

At least we can start thinking and working on these problems while we still have time. When its too late, we may have to come up with workarounds. These workarounds only cause more headache in the longer term.

Picture Source

Improved LTE backhaul via Alcatel-Lucent's 10G GPON

“The PON vendor landscape got interesting in the fourth quarter of 2008, with Alcatel-Lucent, Motorola, and Tellabs each grabbing 10% of worldwide revenue share, behind perennial leader Mitsubishi and the now number-two player, Fiberhome. In the fast-growing GPON segment, front-runner Alcatel-Lucent is being seriously challenged by Motorola, which increased its quarterly GPON revenue share 5 points in 4Q08. Meanwhile, the EPON segment, long dominated by Mitsubishi and Hitachi, is seeing some action as Sumitomo, Fiberhome, and Dasan Networks all moved up.” - Jeff Heynen, Directing Analyst, Broadband and Video, Infonetics Research

I have blogged a bit about GPON and Backhaul before. Click on the links if you havent seen the posts before.

During this year's Broadband World Forum Europe, Alcatel-Lucent not only shows that it masters next-generation wireline and wireless access. The company also highlights that Long Term Evolution (LTE) and next-generation passive optical networking (PON) technologies converge seamlessly for a smooth delivery of the most demanding, high-speed broadband services.

The live demonstration in Alcatel-Lucent's Paris demo center shows LTE's capability to deal with multiple concurrent video streams and fast channel change - and is complemented by a high-capacity 10G GPON backhaul solution for future-safe backhaul via fiber.

Alcatel-Lucent is at the forefront of developing cutting-edge technologies long before they are standardized. Even though the 10G GPON standards are still being ratified, Alcatel-Lucent shows it is ready - when needed - to meet the request for higher capacities in its customers' access networks.

Alcatel-Lucent is engaged in over 95 FTTH projects around the world, over 80 of which are with GPON (as-of Q2, 2009). In Gartner's latest FTTH Magic Quadrant assessment, Alcatel-Lucent was positioned in the leaders quadrant for the fiber-to-the-home space.

Alcatel-Lucent is also opening up details of its optical management and control interfaces (OMCIs) in a bid to help create a true multi-vendor gigabit passive optical networking (GPON) infrastructure.

Announced at this year's Broadband World Forum Europe in Paris, the first version of the OMCI Interoperability Implementer's Guide is aimed at helping other optical network terminal vendors integrate their hardware with Alcatel-Lucent's.

Mobile Backhaul Networks and their Load

These are self explanatory slides on Mobile Network Backhaul presented by Professor Steve Ferguson, Head of Market Strategy, Product Area Broadband Networks, Ericsson in the LTE World Summit last year.

LTE Advanced: NSN Proves relaying technology

Nokia Siemens Networks has broken new ground with another technological first: mobile broadband communications beyond LTE. Company researchers have successfully demonstrated Relaying technology proposed for LTE-Advanced, enabling an exceptional end-user experience delivered consistently across the network.

Completed in Nokia Siemens Networks research facilities in Germany, the demonstration illustrated how advances to Relaying technology can further improve the quality and coverage consistency of a network at the cell edge - where users are furthest from the mobile broadband base station.

Relaying technology, which can also be integrated in normal base station platforms, is cost efficient and easy to deploy as it does not require additional backhaul. The demonstration of LTE Advanced means operators can plan their LTE network investments knowing that the already best-in-class LTE radio performance, including cell edge data rates, can be further improved and that the technological development path for the next stage of LTE is secure and future-proof.

These performance enhancements have been achieved by combining an LTE system supporting a 2x2 MIMO (Multiple Input Multiple Output) antenna system, and a Relay station. The Relaying operates in-band, which means that the relay stations inserted in the network do not need an external data backhaul. They are connected to the nearest base stations by using radio resources within the operating frequency band of the base station itself. Towards the terminal they are base stations and offer the full functionality of LTE. LTE-Advanced is currently being studied by 3GPP for Release 10 and will be submitted towards ITU-R as the 3GPP Radio Interface Technology proposal.

The improved cell coverage and system fairness - meaning offering higher user data rates for and fair treatment of users distant from the base station - will allow operators to utilise existing LTE network infrastructure and still meet growing bandwidth demands.

The demonstration has been realised by using an intelligent demo relay node embedded in a test network forming a FDD in-band self-backhauling solution for coverage enhancements. With this demonstration the performance at the cell edge could be increased up to 50% of the peak throughput.

More info on LTE-A coming soon.