Optical/IP Networks

T- Mobile Busts Backhaul Bottleneck

T-Mobile International AG is taking the HSDPA backhaul bottleneck challenge head-on with the commercial launch of an Ethernet-over-DSL solution from RAD Data Communications Ltd. (See T-Mobile Ramps Up Backhaul, T-Mobile's Backhaul Bugbear , and HR Tracks Backhaul.) By deploying an Ethernet-over-DSL solution, T-Mobile is ahead of the pack as many operators are considering Ethernet-based backhaul to increase capacity in the transport network at a lower cost than deploying many expensive E-1 leased lines. (See Ethernet Backhaul Battle Brews, Carriers Face Backhaul Conundrum, Mobile Backhaul Peaks in 2007, Mobile Carriers Tackle Backhaul Bottleneck, and 3G Drives Backhaul Spending.)

RAD first announced T-Mobile as a customer back in May last year. But now, the German giant has confirmed the success of field trials of RAD's ACE-3000 gateway. T-Mobile has been backhauling commercial high-speed downlink packet access (HSDPA) traffic over the gateway in Germany since late October last year. (See T-Mobile Picks RAD and RAD Tackles HSDPA Transport.)

T-Mobile is also testing the solution in two other European markets, one of which is the U.K., according to Gaby Junowicz, business development director at RAD.

With RAD's backhaul gateway in Germany, T-Mobile uses ADSL2+ lines, which are supplied by Deutsche Telekom AG (NYSE: DT)'s fixed-line business T-Com , to transport HSDPA traffic from the radio access network to the mobile core.

According to Junowicz, T-Mobile has deployed hundreds of the gateways and plans to use them as the backhaul solution for its entire HSDPA network in Germany as well as other European markets.

"Wherever they have HSDPA networks, they will use our solution," says Junowicz. "HSDPA would be dead in the water without this kind of solution. It just wouldn't be possible."

T-Mobile has rolled out HSDPA, with downstream speeds of up to 7.2 Mbit/s, across its 3G network in Germany, Austria, and the Netherlands, according to a spokesman. The operator plans to deploy high-speed uplink packet access (HSUPA) -- which will boost the upstream data speeds to 1.4 Mbit/s -- across the German 3G network by the middle of this year. (See T-Mobile Deploys HSUPA.)

The first mobile operator to go commercial with RAD's Ethernet-based backhaul solution was Japan's 3G operator eMobile Ltd. late last year. (See RAD Wins in Japan.) "They were a Greenfield [3G] operator and had no GSM network… so they had to be profitable from day one from HSDPA," says Junowicz.

— Michelle Donegan, European Editor, Unstrung

lrmobile_postar 12/5/2012 | 3:49:52 PM
re: T- Mobile Busts Backhaul Bottleneck As I see it, using ADSL to backhaul mobile NodeBs does have a big disadvantage.

ADSL is asymmetric, 3Mbps max on the uplink.
NodeBs are usually configured with n x E1.

Isn't this a bottle neck?!
IPobserver 12/5/2012 | 3:49:50 PM
re: T- Mobile Busts Backhaul Bottleneck Hi postar

It would require a long post (or some paid research!) to address your question.

In essence, with DSL youGÇÖre trading quality for lower costGǪ there are lots of carriers both for and against it. Uplink capacity is not the only or even main concern.

That T-Mobile has gone for it in a biggish way in Germany is interesting. Presumably the services are of the high quality youGÇÖd expect. It'll be interesting to see if it validates the model for others.
El Rupester 12/5/2012 | 3:49:47 PM
re: T- Mobile Busts Backhaul Bottleneck There is no fundamental (technological) reason DSL cannot deliver high quality. Indeed T1 and E1 services have been delivered by HDSL for years.

As Gabriel says, the is is quality/cost. If you wanted to, (if you wanted to pay for it) you could negotiate with a landline operator to get "carrier grade ADSL". I wonder if TMO has done this?

Much of the pressure on backhaul capacity is data. You can squeeze a lot of AMR voice sessions into just one E1, after all.

Yes, ADSL is asymmetric. But then again, so is data traffic. This is not a coincidence. I have a HSDPA PCMCIA card that promises 7.2Mbps downlink, and 300Kbps uplink...

IPobserver 12/5/2012 | 3:49:43 PM
re: T- Mobile Busts Backhaul Bottleneck Much of the DSL being considered for backhaul is better than consumer grade. There are even specialist suppliers proposing to use unbundled copper pairs in some markets (UK, for example). It depends on if you can actually get unbundled copper at the cell siteGǪ. That's not always possible in some countries/regions. Beyond that, there are a ton of other things that come into play. (Sync, QOS, reliability, reach, regulation, etc).

T-Mob presented this DSL backhaul concept at our Backhaul Strategies event in Berlin last June. Obviously, it's well thought through.

Like el rupester said, the DSL physically layer is used for E1/T1. Others are proposing to use it for mid-band Ethernet backhaul.

Anything that gives lower cost per bit will help lower the cost of HSPA services to end users and spark innovation in mobility applications.

We're just in the early phases of exploiting HSPA and EV-DO from a services perspective. That's what makes it fascinating.
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