DoCoMo Starts Afresh for LTE Backhaul

The mix-and-match selection of multiple vendors by NTT DoCoMo Inc. (NYSE: DCM) for its Long Term Evolution (LTE) backhaul network has revealed the operator's intention to build a separate infrastructure for the transport of its next-generation mobile data traffic, according to a leading industry analyst.

Alcatel-Lucent (NYSE: ALU) is the latest vendor to win a piece of the cellular backhaul action at DoCoMo for the carrier's planned LTE network.

And the deal is important for two reasons: First, it's positive for Alcatel-Lucent, which is now involved in two of the industry's most ambitious LTE deployments, at DoCoMo and Verizon Wireless ; second, and more importantly, it sheds more light on DoCoMo's backhaul strategy for its next-gen mobile broadband network. (See MWC 2009: Verizon Picks LTE Vendors.)

DoCoMo will use AlcaLu's 1850 optical transport service switch to aggregate LTE traffic from the cell sites to the core network. (See NTT DoCoMo Picks AlcaLu .)

The operator has also selected equipment from Hitachi Ltd. (NYSE: HIT; Paris: PHA) and NEC Corp. (Tokyo: 6701), which were named in March as suppliers for the LTE backhaul network. Hitachi is supplying its Apresia 16000 Ethernet switch, while NEC will supply its CX2800 multiservice switch. (See DoCoMo Backhauls With NEC.)

Since DoCoMo is one of the first operators to roll out LTE, its deployment decisions are closely watched. According to Heavy Reading senior analyst Patrick Donegan, the carrier has opted to build a transport network dedicated to the new LTE network, rather than beefing up existing backhaul capacity that would be shared with its other 2G and 3G access networks.

"My understanding is that DoCoMo’s backhaul aggregation network will be separate from the one used to aggregate DoCoMo’s 3G WCDMA traffic," says Donegan. "This echoes what we are seeing with one or two other lead LTE operators: They plan on backhauling their LTE traffic onto a different aggregation network from their 2G and 3G traffic, sometimes as part of a converged broadband access network combining LTE with, say, a fiber-to-the-home build-out."

One reason carriers would take such an approach, according to Donegan, is that LTE is initially expected to be positioned as a data-only service, unlike 2G and 3G, with voice service added in a subsequent deployment phase. But eventually, carriers are likely to want to merge any disparate backhaul aggregation networks.

"There will be a lot of different implementation models out there," says Donegan. "Certainly those operators that do backhaul their LTE traffic onto different aggregation networks from their 2G and 3G traffic initially, will look to converge those networks over time."

DoCoMo has one of the more aggressive next-generation mobile broadband programs: The carrier aims to roll out LTE services in 2010, and reportedly plans to spend between $3.1 billion and $4.2 billion during the next five years on the technology. (See DoCoMo Shells Out on LTE, DoCoMo LTE Devices in 2010, and DoCoMo Takes LTE to 250 Mbit/s.)

Operators that are not as far down the LTE road as DoCoMo have voiced concerns recently about how their backhaul networks will keep up with the increased capacity that LTE will add to their radio access networks. While it's difficult to pinpoint just how much backhaul capacity LTE will need, due to all the variables involved, each cell site will potentially require more than 100 Mbit/s, according to analysts' estimates. (See T-Mobile, Orange Open Up on LTE and Operators Face LTE Deployment Dilemma.)

For Alcatel-Lucent, the contract with DoCoMo adds LTE and backhaul credentials. The 1850 switch is part of the vendor's Mobile Evolution Transport Architecture (META), which is marketed as a complete backhaul solution that also includes the 7705 service aggregation routers, and the 9500 microwave packet radio product. On this occasion, AlcaLu didn't land an end-to-end deal, because DoCoMo has selected just one network element of META, as well as a management system. (See AlcaLu Targets Wireless Backhaul, AlcaLu Plugs Its Backhaul Hole, Hail Mary: Chan Takes 4G Helm at AlcaLu, and Interview: Alcatel-Lucent's Mary Chan.)

— Michelle Donegan, European Editor, Unstrung