WiMAX takes its place in the mobile broadband patchwork
Motorola takes the lead
Much of the 4G picture remains cloudy, but one thing is clear – the next generation of wireless networks will be based on the OFDMA/MIMO/IP combination shared by the most prominent contenders, LTE and Mobile WiMAX.
For a good few years, these technologies will complement, rather than replace, existing systems like EDGE, HSPA, EV-DO and wireline networks, all of which will continue to be expanded.
This means that the best positioned vendors will be those that can help operators integrate various networks. For all its tribulations, Motorola is taking a clear lead.
The infrastructure supplier will talk up two key announcements at last week's CTIA conference in Las Vegas – a common platform for LTE and WiMAX, and hand-off between LTE and EV-DO. The former will take advantage of the many similarities between the two leading OFDMA technologies, with Motorola citing development overlap of up to 80 per cent.
The company has announced software configurable modem technology, and senior vice president Fred Wright said in a statement: "We're building upon our OFDM expertise and early success in WiMAX 802.16e as we develop our LTE product solutions. We can reuse about 75 per cent of the basic application software and platform technology we developed for WiMAX in our LTE products, thereby advancing our development efforts.
"For example, the new common wireless broadband platform is expected to be commercially deployed in WiMAX networks in 2008, followed by the LTE application available by late 2009, giving us the advantage of deploying LTE technology on a field proven platform."
A combined platform is also the goal of Nortel and other base station makers that have eschewed a religious stance on next generation systems, and they hope that the ability to target the whole operator base with a unified architecture will deliver them faster 4G uptake, greater economies, and give them an edge over market leader Ericsson, which is sticking to LTE only. Nokia Siemens Networks is looking to support both standards in its Flexi Base Station flagship, although it is also working on a fully unified platform for future release.
Motorola's second breakthrough is to demonstrate hand-off between EV-DO networks and LTE, which will be important in targeting what should be low hanging fruit for the CDMA infrastructure makers – operators migrating from CDMA to LTE, as it looks increasingly unlikely that Qualcomm's own OFDMA/MIMO design, Ultra Mobile Broadband (formerly EV-DO Rev C) will ever come to market.
Most immediately, CDMA giant Verizon Wireless plans to start trialling LTE late this year, with a view to a 4G strategy that is harmonised with its co-parent Vodafone. The largest operator by revenues will be a keen target for all the vendors, but the CDMA makers will be particularly eager to get into this UMTS stronghold, using Verizon as the back door.
The Lucent side of AlcaLu and Nortel are the other main contenders in this sector, with ZTE also a possible challenger, given its rapid growth and its CDMA presence in emerging markets.
Danny Locklear, director of wireless product marketing at Nortel, said in a recent interview that the Canadian firm can differentiate itself from competitors by focusing on LTE for CDMA operators, while supporting the continuing expansion of EV-DO systems in parallel, as CDMA providers introduce enhancements like VoIP.
Motorola's demonstration was the first successful packet switched hand-off between EV-DO Rev-A and LTE, and showed VoIP calls and streaming video.
"This gives us confidence that LTE is progressing in the right direction," said Chris Smith, executive VP at another CDMA operator, Alltel. "It is going to be incredibly important for LTE to interoperate with our existing technology as this is one of many key functionalities that will play a critical role in our final decision making."
While the LTE standards are still not finalised, the handover mechanisms used by Motorola were based on part of the specifications that is all but frozen – the non optimised handover procedures in LTE core network SAE standard 3GPP TS 23.402.
Some operators will have even more complex combinations of technology to support. Sprint Nextel will use CTIA to showcase its Xohm WiMAX-based service, and distract attention from the woes of its CDMA and iDEN networks – in particular, the widest range of real world WiMAX and multimode devices yet seen will be on show, even if in prototype.
And Japan's KDDI, another CDMA major, recently won a national WiMAX license in 2.5GHz, via a consortium that it leads, but also pledged last week to roll out LTE from 2010. The Japanese Ministry of Communications is keen for all the leading cellcos to support a common 4G platform, and NTT DoCoMo and Softbank are already committed to LTE.
Meanwhile, as at the Mobile World Congress show in Barcelona in February, CTIA will also see heavy emphasis on continuing enhancements to EDGE and HSPA. Ericsson is demonstrating HSPA+ (which incorporates MIMO, among other upgrades) with downlink speeds of 42Mbps over a 5MHz channel, a product it says will be commercially available this year. Ericsson is pushing HSPA in the 2.6GHz band, as well as more conventional UMTS frequencies, part of its bid to sideline WiMAX, which views this band as a natural home, at least until LTE rolls out.
On the EDGE front, Nokia Siemens has announced a software upgrade called Dual Carrier EDGE. This boosts the speed of the network – a GSM enhancement that supports data, and is economical for rural or low intensity users – to 600Kbps over existing infrastructure.
NSN said the product will be available in the third quarter, as part of the company's strategy to promote EDGE as a true mobile broadband technology – a cause much boosted by the success of the EDGE-based iPhone in the US. NSN also plans to introduce the next substantial step, the so-called EGYPTS 2, to achieve downlink speeds of up to 1.2Mbps and double uplink speeds to a peak of 473Kbps, thus quadrupling the capabilities of EDGE today.
"By 2015, we expect to live in a broadband IP world with five billion people 'always on'... Dual Carrier software upgrade is an easy and extremely cost efficient step to bring broadband user experience to GSM/EDGE networks", said Ari Lehtoranta, head of radio access for NSN.
Copyright © 2008, Wireless Watch
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For all the news on the CTIA Wireless trade show see our CTIA roundup.