2.6 GHz Spectrum & the Next Generation Mobile Broadband Networks

As the much awaited 2010 Mobile world Congress will kick in on 15th February in Barcelona, Spain, primary focus will be on discussing and showcasing the future of mobile broadband industry with cutting edge products, technologies highlighting m-commerce, m-marketing, m-advertisements, broadband deployment and initiatives broadening the mobile ecosystems.

“There is clear evidence that the volume of data flowing over mobile networks is growing rapidly and is being accelerated by the popularity of smart phones and the growth in music and video downloads,” said Tom Phillips, Chief Regulatory Affairs Officer at the GSMA.

With this unique and new view of the mobile landscape unfolding, one of the primary driver will be the utilization of ever scarce resource: Spectrum. The licensing of the 2.6 GHz spectrum will be vital in satisfying the demand for greater capacity for Mobile Broadband and launching next-generation networks such as LTE, which will start to be deployed commercially around the world this year .

As I mentioned in my previous article covering the WiMAX business model highlighting the importance of the spectrum and its contribution in the wireless operator's cost model. Building on it we now know that the licensing of the 2.6 GHz band will be critical to unlocking the benefits of global scale economies in the Mobile Broadband market. The outcome of 2.6GHz allocation will have far-reaching consequences for how the adoption dynamics of WiMAX and 3GPP (such as HSPA and, in future, LTE) will play out in this region since 2.6GHz is the first arena where the two proponents will be battling each other in the same area of spectrum.

So let's jump in discussing and analyzing about the 2.6GHz band its importance, what’s in store and bullet its implications on the future of mobile broadband. This analysis extends the scope of the report on 2.6 GHz band recently released by the GSMA & GVP. This report maybe biased towards LTE but lets draw some real pointers and analyze it.

Digging in about 2.6GHz band..

The 2.6 GHz band (2500-2690 MHz), sometimes also referred as the 2.5 GHz band, was allocated by the World Radio communication Conference (WRC) in 2000 for terrestrial mobile communications services. The 2.6GHz band is often referred to as the "IMT-2000 expansion band"(now !!) or the "3G expansion band"(earlier) and is 190MHz wide (substantial !!). This band has been allocated on primary basis to all the three ITU regions for terrestrial mobile communications compared to the smaller allocation of 3.5 GHz (3.4-4.2 GHz) Why ??

Note: ITU Regions: Region 1 comprises Europe, Africa, the Middle East west of the Persian Gulf including Iraq, the former Soviet Union and Mongolia; Region 2 covers the Americas, Greenland and some of the eastern Pacific Islands; Region 3 contains most of non-former-Soviet-Union Asia, east of and including Iran, and most of Oceania.

WRC imposed stringent power limits on satellite systems with limited geographic footprint operating in 2.6 GHz band shifting the importance of satellite systems more into 3.5 GHz bands. Also to add to this WRC-07 decided against the global identification for IMT, including WiMAX, in any part of the satellite C band (3.4-4.2 GHz)  with an exception of the mobile service allocation in 3.4-3.5 GHz thus making this band less globally harmonized for IMT. Hence the 2.6GHz band is now in a unique position to be exploited as a common band for commercial terrestrial mobile broadband access services on a global basis. The beauty of the 190MHz wide spectrum is how it is to be divided for allocation. Should it be paired or unpaired suiting to corresponding FDD and TDD modes of operations. The International Telecommunications Union (ITU) presents three possible options:

Option I: A mix of FDD(paired) and TDD(unpaired) spectrum plan which avoids interference problems this two different modes of operations

Option II: No unpaired spectrum included in this plan and leaves the second member of each pair undetermined

Option III: A Flexible plan on the amount of spectrum allocation for either of the paired(FDD) or unpaired(TDD) modes of the operation

The adoption of above plans differs from region to region, country to country and market to market depending upon the  technology Standard to be deployed either HSPA/HSPA+, LTE or WiMAX. A channel width of 20 MHz is recommended for most efficient use of current technology capabilities  for FDD (2x20 MHz) as well as TDD (a 20 MHz block is sufficient). Licensing should be based on a structure of 5 MHz channel blocks to allow support for 5,10, 15 or 20 MHz channels dependent on spectrum availability and each market’s competitive situation. Future technology evolution (4G) will most likely be based on combining multiple channels with 20 MHz being an ideal building block.

The ITU Option 1 band plan is well suited to meeting this goal by enabling technology neutrality and competitive ―4G‖wireless equipment choices for both FDD and TDD operation to mobile operators (including both LTE and WiMAX).There is widespread agreement at national levels as well as at the European Union and its Commission in adoption of Option 1 band plan. Recent licensing carries a bias toward Option 1 with slight differences related to country-specific situations. More auctions are expected in Europe as well as in major emerging markets such as Brazil and South Africa. Substantial 2.6 GHz spectrum is licensed in the United States, although allocation and utilization are less than ideal for unique, nonreproducible historical reasons that predate the allocation of this band to mobile communications.

The ITU Option 2 band plan does not accommodate demand for unpaired spectrum and, therefore, violates the principle of technology neutrality (WiMAX)

The ITU Option 3 might lead to is likely to lead to multiple different national band plans and other challenges such as regulatory hurdles coupled with interference management and costs and availability of the equipment to match up in a customized way to the different national band plans. It increases the need for guard bands and could drive costs up for spectrum owners since they would need to negotiate with each other to make sure efficient coexistence and sacrifice spectrum to use as guard bands

2.6 GHz Spectrum implications:

Socio - Economic Implications

• Expanding the wireless mobile broadband to developed as well as developing nations  at affordable price points

• With a standardized spectrum bands and allocations plan allowing global harmonization will help drive economies of scale driving the costs down

• Standardization also enables easy and ready accessibility of the common services across many geographies.


• Economic reuse and sharing of existing physical and operational infrastructure  of the mobile operators reducing CAPEX (deployment costs)

• Proper Spectrum standardization and band plans options enables technology (FDD/TDD) and service neutralities  facilitating innovation and healthy competition between equipment, device, and applications and services vendors to the benefit of customers

• The widespread mobile broadband deployment and growth have potential benefits (employment, GDP) for developed economies and in fact more for emerging economies.

Technological Implications

• LTE and WiMAX can exploit 20 MHz of contiguous spectrum to deliver their highest spectral efficiency and highest throughputs. The 2.6 GHz band makes such allocation possible enabling the operators to operate high-speed LTE/WiMAX services at optimum performance.


• The 2.6 GHz frequencies have relatively short propagation ranges and inferior in-building penetration characteristics compared to lower frequencies makes it less suitable for rural areas( But with beam forming this can be taken care of..)


• On the other hand, the short propagation range and the large amounts of bandwidth (190 MHz) available in this band make it ideal for operators seeking to offer high network capacity and improve the speeds of mobile data transmission they can deliver to users in urban and suburban areas.


• Looking ahead, the shorter 2.6 GHz wavelengths can achieve greater improvements in performance through increased use and capabilities of smart antenna techniques such as MIMO and beam forming than is possible at lower frequencies. Thus, the gaps between environments in which 2.6 GHz can be used economically and efficiently relative to those where frequencies below 1 GHz are better suited may be somewhat reduced in favor of 2.6 GHz.


• The 2.6 GHz spectrum is the ideal complement to the 700 MHz spectrum, also known as ‘digital dividend’, and will enable the most cost-effective nationwide coverage of Mobile Broadband across both rural and urban environments. Also, LTE is likely to be of interest in other bands (e.g. 1800 MHz in Finland and Hong Kong).


• Though I mentioned at the start 2.6 GHz was seen as the "3G Extension band" but the ITU has changed its destination to the IMT band (for all mobile applications) positioning it strong for growth of 4G technologies (LTE Advanced & 802.16m).

2.6 GHz Adoption Facts:

• Recent licensing of this band in Hong Kong, Norway, Finland and Sweden, for example, has highlighted that there is more demand for paired (FDD) than unpaired spectrum (TDD) and that the ITU’s recommended Option 1 plan is the best structure to stimulate market growth in a technology-neutral and competitive environment. With an

• In the United States band plan, incumbents have the flexibility to deploy Time Division Duplex (TDD) or Frequency Division Duplex (FDD) anywhere in the band (Option 3) . Here the major spectrum owners are Sprint & Clearwire deploying TDD WiMAX which will be followed by future LTE rollouts by Verizon Wireless possibly in 700MHz band and AT&T is currently focusing on HSPA/HSPA+ networks to match up to WiMAX speeds.

• Governments in most Western European countries as well as in Brazil, Chile, Colombia, and South Africa are planning to award 2.6 GHz frequencies within the next two years.

Summarizing the benefits, implications, facts and the mobile broadband trends, 2.6 GHz spectrum ownership and band allocation can shape the business models for the next generation technologies. It will be a significant part in developing a wireless ecosystem which will offer high-speed mobile broadband solutions which shall  be easy to access, seamless across geographies and at an affordable price !! - Neil Shah

References:

Unstrung.com Report : 2.6GHz Spectrum Key for LTE
Maravedis-bwa.com : Europe Prepares for 2.6 GHz spectrum Feeding Frenzy
Five bidders take 2.6 GHz WiMAX spectrum in Norway
GSMA & GVP Report on "The 2.6 GHz Spectrum Band"
WiMAX Forum 2.5 GHz Spectrum Manager
Light Reading : GSMA Wants More LTE Spectrum
3G Americas: LTE Global Deployments
WiMAX Vision.com4G battle looms in Europe at 2.6GHz