LTE: why now?

LTE is still a few years away and many questions about the technology and business model remain unanswered. So why are many operators and equipment vendors betting on LTE today?

This is a simple question, with many different answers. While some operators view LTE as a disruptive technology, others see it either as an evolutionary path from their current technology, or as a complement.

For example, according to Telstra executive director Mike Wright, LTE will not replace the Australian telco's HSPA network that was deployed earlier this year, but rather will serve to complement it where there are capacity issues or more spectrum is needed. Telstra wants to utilize different spectrum ranges.

LTE will provide the flexibility of using 900 MHz; at some point they will want to utilize their 1800 MHz spectrum and may also want to acquire 2.6 GHz spectrum if extra capacity is needed. One major advantage Telstra sees is that LTE is much more flexible when it comes to awkward-shaped channels. For instance, at 900 MHz Telstra has 8.4 MHz of bandwidth. LTE will provide much more efficient usage of that type of channel than would W-CDMA.

The evolution to LTE is also compelling for some operators because of reduced capex and opex compared to previous 3G networks. Some will be able to leverage their existing 3G networks to upgrade to LTE. For those without a mobile/cellular infrastructure, deploying an LTE network might not be a cost effective solution.

For Telecom Italia, LTE will be an overlay technology for its 3G network to provide higher bandwidth services. Alberto Carnellio, director of business innovation at Telecom Italia, argues that 3G and HSPA have been very successful, and sees 4G as an evolution from 3G and HSPA that will bring improvements in terms of efficiency and performance. A question to keep in mind is what would happen if traffic grows beyond HSPA capacities? What about spectrum availability?

Joachim Horn, CTO of T-Mobile International, says that HSPA has been developing well. The operator plans to continue profiting from this development, but foresees a limitation in capacity in a couple of years as traffic increases. T-Mobile will start deploying LTE as a host-spot high traffic zone solution, and as the technology matures and interoperability issues are resolved, it expects a major rollout of LTE.

Cost savings and flexibility

Another common thread driving the deployment of LTE will be the increasing demand for mobile data and video services at the lowest cost per bit. For MetroPCS in US the move to LTE provides two things: capacity and speed. MetroPCS has picked LTE as its 4G standard, following the lead of Tier 1 operators Verizon Wireless and AT&T Mobility. MetroPCS is skipping EV-DO deployment and moving straight to LTE. The operator aims to deploy LTE to address the rapid increase in multimedia traffic. It offers bandwidth-hungry apps like Facebook Mobile, MySpace Mobile and Loopt.

LTE also promises to provide great flexibility to operators in determining the spectrum in which it will be deployed. Not only will LTE have the ability to operate in a number of different frequency bands including the 2G and 3G spectrum, which are already widely available worldwide (meaning operators will be able to deploy it at lower frequencies with better propagation characteristics), but it also features scalable bandwidth.

Whereas WCDMA/HSPA uses fixed 5 MHz channels, the amount of bandwidth for an LTE system can be scaled from 1.25 to 20 MHz. This means networks can be launched with a small amount of spectrum, alongside existing services, and adding more spectrum as users switch over. It also allows operators to tailor their network deployment strategies to fit their available spectrum resources.

But how much spectrum is required in order to deploy LTE profitably? According to T-Mobile International's Joachim Horn, at least 21 MHz is required to deliver 170 Mbps downlink using MIMO antennas. The company is planning to deploy in the 2.6 GHz band spectrum, which is likely to be auctioned in many European countries in 2010, starting in the UK. T-Mobile International also envisions deploying LTE in all its available frequency bands for GSM and UMTS, but this is not likely to occur until 2015.

Why wait?

The question that still remains for many is why are some operators deciding to immediately invest and deploy LTE, while others have adopted a "wait and see" approach? 

One explanation is that operators' spectrum assets determine the technology and timing of deployments. In Europe for example, many operators strongly committed to LTE will have to wait for spectrum allocation to take place, especially in the 2.6 GHz band. Operators such as Telecom Italia and Vodafone UK are preparing the terrain for deploying LTE, but until these auctions occur it is difficult to anticipate the timing.

An exception is Hong Kong's SmarTone-Vodafone, which is basing its LTE strategy on its existing 900/1800/2100 MHz spectrum. The operator bowed out of a 2.6 GHz spectrum earlier this year on the grounds that the price was too high, with CEO Douglas Li saying its mobile broadband evolution could be served by refarming existing spectrum capacity.

Another explanation is the distinction between CDMA and UMTS service providers: CDMA operators - with no migration path remaining on their 3G networks - are proceeding directly to 4G, while UMTS providers have plenty of upgrades left for their HSPA networks.

AT&T for example, is in no rush to deploy LTE, as it has been adding thousands of new cell site backhaul connections to support the higher mobile broadband speeds enabled by HSPA 7.2. For AT&T, LTE will add more network capacity and higher bandwidth speeds to satisfy the increasing demand for data services. However the operator plans to continue deploying HSPA, increase bandwidth to 14.4 Mbps this year, then move to HSPA+ and finally deploying LTE sometime in 2012.

According to Motorola general manager Fred Wright, CDMA carriers are motivated to adopt LTE because "they want to hop on the bandwagon of a global standard that will provide multiple supply sources for infrastructure, lots of device alternatives and multiple chip supply sources. All those things are good from the operators' perspective because, with more volume and more scale, they get better pricing and more alternatives. As good as EV-DO-A is, there is no next step on its roadmap."

The nature of various 3G networks is a big determining factor when it comes to the timing of operators' LTE network deployments. This means that for some operators the upgrade path to LTE will be more gradual than for others. Of course, operators having deployed their 3G networks last year using technology that is "LTE-ready" - or, in the case of Hong Kong operator CSL, revamped their old 3G network to make it LTE-ready - have a much greater advantage, as they all they require is a simple network upgrade.

Cintia Garza is team lead and market analyst for CALA at Maravedis' 4GCounts
 

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