LTE on the horizon

With TeliaSonera and Verizon both launching LTE services, we are on the cusp of another major step in mobile communications.

LTE on the horizon

Faster, reliable mobile bandwidth is coming soon to a phone near you as mobile carriers adopt LTE (Long Term Evolution), a network technology upgrade to 3G. At the forefront of the technology's deployment has been Verizon, the US mobile operator that will launch LTE services in the next few months. But the American carrier has been beaten to launch by Scandinavian network TeliaSonera, and there are others poised to roll out the technology.

In contrast to previous mobile network technology upgrades, LTE offers carriers the opportunity to provide their users with greater speeds and lower latency without starting from scratch with new network construction. As the name suggests, the technology provides a long-term evolution to greater speeds and reliability in the mobile network.

The benefits are obvious, claims Jean-Pierre Bienaimé, president of the UMTS Forum. 'LTE is a smooth evolution of today's mobile broadband experience,' he says.

'Initially focused on non-voice services, it's all about providing greater data speeds and lower latency. This means a more pleasurable internet experience on the move and, for operators, it's the logical way to add extra capacity to support the huge increase in non-voice traffic that we're already starting to see on existing networks.'

Verizon's deployment will see LTE rolled out using the 700MHz frequency bands for data services only. This is the frequency used to support US analogue television, and is cheaper than the alternative 1900MHz waveband. Verizon will initially launch services in Minneapolis, Boston, Chicago and Seattle, but is in a similar position to AT&T, which has LTE deployment plans for 2011. Both are yet to announce plans to deploy IP voice over LTE because concerns remain over whether mobile IP voice can match the quality users already receive using 2G networks. In addition, IMS (IP Multimedia Subsystem) technology - the intended means by which operators will support voice over LTE - is not yet ready, so at launch at least, LTE won't support voice. Verizon has gone on the record stating that it fully expects its current 2G network to support voice calls until 2020. Given the rising demand for data from smartphone users, it's likely that each network will offer multi-mode phones with data at 700MHz and voice at 1900MHz.

LTE does deliver greater speed and capacity. Network vendor Huawei, which is working with TeliaSonera and T-Mobile and has conducted field tests and trials with Vodafone, China Mobile and Softbank, claims a peak data rate of 173Mbps has been achieved on the downlink - setting a new record in terms of wireless transmission peak data rate. The company has also seen data rates on the uplink of 84Mbps.

The user reality

However, the reality for users will range from LTE simply providing an incremental advance over their existing 3G connections to, at the higher end, revolutionising the functionality of their mobile devices. The capacity available will vary widely from deployment to deployment. 'LTE doesn't inherently guarantee users any specific level of experience or availability of new features,' explains Lance Hiley, VP of market strategy at Cambridge Broadband Networks. 'In theory, by delivering high capacity data to handsets and netbooks, users will be able to make use of more data intensive services and features such as video, bringing the mobile experience to something that more closely resembles that of fixed-line broadband on a desktop computer.

The major barrier between the theories of what LTE can deliver and what it actually will deliver comes down to quality of service and the knock on effects this has on quality of experience.'

For Bienaimé, LTE will be predominately used for transferring large files and will present a step up from High Speed Packet Access (HSPA) technologies currently being used to access corporate Virtual Private Networks (VPNs) on the move. 'We're also expecting to see new vertical application areas,' he adds. 'These include location-based content for navigation, transport and location, online mobile banking, ecommerce, remote health diagnosis with video support and back-up storage for field workforces.'

Saul Friedner, principal consultant at Mott MacDonald, thinks the evolutionary nature of LTE makes it difficult to identify services that will be exclusive to LTE. 'It is difficult to predict which services will run over LTE,' he says. 'It is easier to suggest which services can run over LTE and determine which are likely to be the most popular. For example, VoIP has been a growing success over the last few years on fixed networks and it is likely that VoIP uptake on mobile networks will increase. LTE is optimised for voice, having low latency and jitter. However, the potential throughput of up to 100Mbps per sector that LTE offers makes video streaming and download viable.'

It is that reliable, low latency access to improved bandwidth for mobile data that is LTE's selling point. Applications developers and other operators will be watching TeliaSonera's lead closely - along with Verizon's larger deployment - and only then will they be able to establish the business case for their own deployments. What seems clear is that, regardless of the pioneers' experiences, LTE has been embraced by the carrier sector and, provided backhaul capacity can be made available to support the radio access networks, LTE opens the doors to many new applications as well as improved reliability and data throughput for existing applications.

What will deployment cost?

Although described as an evolutionary upgrade, it is disingenuous to consider LTE as a low cost means of adding extra capacity to mobile networks. Operators won't have to start from a blank sheet but they will have to make considerable investments to roll out the technology. Consultancy Mott MacDonald cites a prediction from technology vendor Aircom International, which has projected that the cost of an LTE rollout for Verizon will be US$1.78bn. Aircom also predicts that the cost of an LTE rollout for a UK operator will be approximately £455m.

'LTE will require carriers to deploy new antennae and new channel cards,' adds Larry Fisher, director of engineering and research at wireless networking company ADC. 'The antennae will have unknown characteristics, few existing base stations will support conversion to LTE and the carriers will need to significantly increase backhaul capacity. The cost will probably be 1.5 times what it cost carriers to go from analogue to first generation PCS digital networks.'

However, cost will be variable. 'Most of the cost of deploying an LTE network for an existing 3G operator represents its investment in the radio access network - typically this can represent at least 50% of the total cost,' says Bienaimé at the UMTS Forum. 'Then

you've got to factor in the costs for backhaul and spectrum licensing. Overall, cost of deployment can vary hugely and depends on factors such as the population coverage being targeted and also the "integrated" solutions being offered by several manufacturers.'

Saul Friedner, principal consultant at Mott MacDonald, identifies first mover disadvantage. 'The costs of deployment of LTE for those who adopt the technology early will be higher than for those who wait a while because equipment in the early stages of rollout will be expensive. In addi

Written by Wireless magazine
Wireless magazine

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