Interest in the technology reflects its potential, and LTE, with up to 160 Mbps available to users, and standards close to acceptance, is top of mind for many.
Over 55 000 visitors convened recently at Barcelona's Mobile World Congress (MWC) to do business and debate the future of the industry. The hot topic of the event, as evidenced by technical demonstrations, presentations and discussions among delegates, was long term evolution (LTE).
LTE's standards are close to acceptance and may still be published this year and the discussions at MWC focused around evolved UMTS radio access (E-UTRA) for mobile requirements and systems architecture evolution (SAE) for the core. About 80% of the specifications are in place for the access network and about 60% for the core. With the path to resolve remaining issues clear, we are confident that, by close of quarter three 2008, LTE will be ratified to define the infrastructure for unprecedented mobile performance.
Faster, wider and more efficient
LTE delivers broadband that is way beyond current perceptions of fast. The peak download rates of 160 Mbps are achieved by adopting orthogonal frequency-division multiple access (OFDM) technology. OFDM splits signals into numerous subcarriers that transport the information at lower bit rates. The composition of OFDM makes it particularly robust especially in demanding environments (eg, urban areas).
LTE is also an exceptionally efficient and versatile air interface: it generates 2,5 times the sector throughput of HSPA+ while boosting performance at the edge of coverage and enabling spectrum to be used from 1,4 MHz to 20 MHz. Speeds in the up-link are impressive also, reaching 80 Mbps thanks to the adoption of single-carrier FDMA (SC-FDMA). SC-FDMA has a number of advantages for up-link demands with a vital benefit being the reduced consumption of terminal battery power compared to alternative technologies.
Enhancements to the air interface delivered by LTE are complemented by the integration of multiple-input and multiple-output (MIMO) and smart antenna technology to improve communication performance. MIMO achieves a key goal of LTE by providing a long-term development path for data intensive applications; ultimately 4x4 antenna patterns could accelerate throughput towards 300 Mbps.
While warp-speed broadband will grab consumers' attention, an equally important contribution to the user experience are SAE specifications; flat all-IP architectures will orchestrate services with no noticeable delay (latency is below 10 ms) and provide a connection point for other access technologies to enable true converged services and media mobility across fixed and wireless networks.
Designed from scratch to accommodate the demands of evolving applications, LTE is acknowledged as the pre-eminent mobile platform for the future. Networks are now publicly affirming their commitment to the technology and, with trials getting under way, the launch of services is on the horizon.
This year, Motorola will take part in a multivendor trial of LTE that involves initial lab-based phases to review the performance and the benefits of LTE. Moving forward, the trials will take to the field to measure real life performance in various environments, handover between LTE base stations and the benefit of various MIMO antenna configurations. We are able to accelerate interface testing by calling on the comprehensive bank of the live network data collated from our extensive live commercial implementations of WiMAX that also integrates similar MIMO and OFDM techniques.
Darren McQueen, Motorola’s vice president of cellular and broadband access technologies
By the first quarter of 2009, we will be in a position to evaluate interworking between LTE, HSPA and GSM to support seamless mobility (as users move across networks). This is one of the final tasks ahead of the commercial launch of LTE that provides the infrastructure to support an impressive array of enhanced and new services while also providing seamless connectivity to legacy networks.
LTE will significantly advance communications services. Voice over IP for example will be conducted in hi-fi quality, HD video conferencing will be available and applications such as instant messaging and e-mail will be as rewarding to use as they are on a PC today.
Beyond advanced communications, we see great potential in media services:
Broadband anywhere: With broadband that goes anywhere subscribers go, personal content is continuously available (eg, TV programming, audio files, videos, games and images). Entertainment will be stored on a digital content library, most likely in the form of a PVR or media server. If new content is added, the index will be updated across all devices to support cache and carry so that users can easily access and watch a show recorded overnight on the way to work or download movies from their library to watch in their hotel room.
The world in my pocket: Entertainment extends beyond personal content. Mobile TV, video, the ultra high-speed Internet, and DVB-H broadcasts will provide a world of entertainment in the pocket: subscribers can watch their favourite shows whenever they have time to kill, from the airport to the grocery store queue; take five minutes to catch up on friends' video blogs; save the galaxy in an online game on the bus; and pass train journeys with the latest blockbuster.
From consumers to creators: LTE provides the infrastructure for subscribers to become film directors. Social networkers and bloggers will be able to use the mobile device to easily document and share their experiences with the option to capture and load HD videos to their sites. Content creation will also be valued by the wider community of users. Devices will provide the capability for all images and video captured by users to be automatically transferred to digital content libraries (be this network-based storage or a PVR) or Internet properties such as Flick. E-mails, instant messages, MMS or SMS can then be sent to family members and contacts (to inform them that new images are available) who can log onto the site or content library to view them.
The breadth of services available via LTE has generated confident predictions about the technology's impact.
The analyst firm Analysys indicates that by 2015, revenues from LTE could be as high as €150 billion generated by an estimated 400 million subscribers to LTE networks. While current data revenues account for 15% of service provider earnings, this figure may jump to 36% in the wake of the technology's introduction. Such strong projections take into account the global reach of LTE and the fact that, due to its inherent spectrum flexibility, service providers can build infrastructure to launch services in spare capacity and ramp up their investments as demand grows for data intensive applications.
From promise to build
LTE has long been recognised as a key 4G technology. With standards close to full publication, service providers commencing trials and consumers increasingly demanding advanced data intensive applications, we are moving from promise to build. We have made great strides in the development of infrastructure and handset chip sets and, while many market observers predict that LTE systems will not be widely available until 2010 or 2011, we expect the first systems to be up and running in as little as 18 months. Where LTE is concerned, the future is almost ready now.
LTE: a Leap in performance
There has been much discussion about the relative merits of HSPA+ and LTE. On paper both technologies provide similar peak data speeds at similar bandwidth (limited by Shanon’s principles) but the changes and technical enhancement introduced by LTE deliver major advantages to service providers both in terms of total cost of ownership and real-life subscriber performance. In effect, sector throughput (a much more realistic measure of the actual performance of a mobile network) on LTE is close to 2,5 times greater than that of HSPA+ in the same spectrum bandwidth. This increase in performance complemented by the ability to expand LTE bandwidth up to 20 MHz (4x HSPA+), has a direct impact on network capacity and leads to significantly lower OPEX and CAPEX.
Moreover, with HSPA Plus handsets not expected to be ready for some time together with the fact that legacy devices will need to be replaced, the benefits of HSPA+ may not be realised in the field until later in 2011. Given the jump in performance that LTE represents, the consensus among the service providers we speak to is that most are considering limited roll-outs of ‘Plus’ and are focusing investment on the broader implementation of LTE.