With the close of broadband wireless access (BWA) spectrum auctions, there has been a lot of speculation in the industry with regard to the technologies that are likely to be adopted for deployment. tele.net spoke to leading industry experts about the BWA technology options, especially Wi-Max and long term evolution (LTE) which are currently ruling markets the world over...

Which technology option -­ time division (TD)- LTE or Wi-Max -­ is likely to be adopted by operators for providing BWA services?
Parag Kar
LTE is the technology best suited for current and upcoming 3G deployments and for addressing India's rapidly growing demand for high bandwidth broadband services. LTE is compatible with both 3G HSPA and EVDO, and offers a unique opportunity for operators with TDD spectrum to integrate with the 3G/LTE ecosystem. LTE in BWA spectrum will enable a 3G and BWA experience rather than a 3G or BWA experience. In comparison, alternative technologies positioned for BWA offer a stranded investment and a weak business case due to their lack of interoperability with existing wireless technologies.

Purushothaman K.G.
The reason why some operators are considering using TD-LTE over Wi-Max is that it offers up to 100 Mbps for downlink and 50 Mbps for uplink, which is far superior to Wi-Max. Moreover, it offers greater spectrum efficiency.

The operators' decision to consider either of the two technologies depends largely on their bandwidth requirements and the costs involved. At present, the worldwide capex for TD-LTE is slightly on the higher side. On the opex side, the key factor is the operators' agreements with the vendors. So, the biggest challenge for these operators will be to negotiate good deals on the equipment, network and cost per equipment with vendors.

Wi-Max, however, has been tested while TD-LTE is still in the testing phase.TD-LTE is currently being tested in European countries like Sweden while it is in the launch phase in the US. Its launch in South Asia has, however, been delayed.

C.S. Rao
Telecom companies would consider the following 10 criteria while choosing their BWA technology:

•  Best capex, opex and return on investment models
•  A range of subscriber devices matching Indian consumer affordability
•  Ability to offer best quality services at affordable prices to all segments
•  Conforming to globally harmonised spectrum usage
•  International adoption status to ensure roaming
•  Scalability to match society uptake in tens of millions, if not hundreds of millions
•  Ability to exploit global scales of economy of the technology
•  Solid road map for migration to nextgeneration capability
•  Support of vendors for network infrastructure and end-user devices
•  Conforms to global and Indian telecom regulatory/policies and standards.

On all the above attributes, Wi-Max scores 9 on a scale of 1 to 10, with 10 being the best. Any competing technology scores, at best, a 2 and the fact is that such technology lacks any level of commercial readiness, leave alone standards and deployment readiness.

Wi-Max has been adopted by countries like the US, Japan, Russia and Malaysia that have had 3G for over a decade.

Santosh Sinha
Proponents of both Wi-Max and LTE would like to see their technology being adopted for wireless broadband access.Qualcomm has bought BWA spectrum in order to introduce LTE technology in India. However, a lot will depend on the final decision of Reliance Industries Limited (RIL)-owned Infotel Business Services, which has expressed its interest in LTE technology.

What is the business case for LTE and WiMax in India?
Parag Kar
We expect LTE to be initially deployed in the central business districts of urban markets to address the demand for high bandwidth broadband services, working seamlessly with 3G, which will have carpet-tocarpet coverage throughout the city. The biggest advantage of LTE is that it interworks with 3G, both HSPA and EVDO, which are further backwardcompatible with 2G GSM and CDMA 20001X. In a likely scenario, an operator could deploy LTE using BWA spectrum in dense urban pockets, HSPA or EVDO throughout top cities, and continue with 2G elsewhere.

As LTE comes down the price curve, it will continue expanding within cities, and as 3G too comes down, it will continue expanding its reach pan-India. Finally, voice and data will be simultaneous in 3G and LTE devices and LTE will be interoperable and hand off to 3G. This would enable Indian operators to optimise and futureproof their investments.

Wi-Max, on the other hand, lacks the scale and service differentiation necessary for truly ubiquitous mobile broadband. At best, the Wi-Max platform may be viable in niche pockets in urban areas, offering fixed connectivity to homes and offices.
There is no business case for Wi-Max in rural India, as the opex involved in the rollout of services would be so high that it would practically negate any profitable business proposition.

Purushothaman K.G.
As of now, there is a business case for WiMax due to the availability of equipment as well as the presence of known vendors in the market. But with the spectrum licence fees going through the roof, they will have to reconsider whether they want to invest in this technology now or wait for a new Wi-Max standard -­ 803.16N -­ in place of the currently deployed 803.16E. The new standard, which is expected to enter the market in the next few years, is supposedly at par with TD-LTE.

From a long-term perspective, however, TD-LTE will offer better value since operators worldwide are opting for system architecture evolution, which is expected to reduce their capex significantly by bringing in equipment that will serve a larger subscriber base per base transceiver station (BTS). At present, the subscriber base for Wi-Max is 700-800 per BTS whereas TD-LTE can afford up to 1,100 subscribers per BTS.

C.S. Rao
With Wi-Max spectrum of 20 MHz, Indian BWA bidders can roll out the technology at a capex per subscriber of less than $10, offer subscribers devices without any subsidy ranging from $40-$60 to $300, depending on the device being a data card, indoor CPE, a smartphone from companies like HTC, Samsung, LG or an embedded netbook/notebook from companies like Lenovo, Samsung, Sony Vaio, Acer, Asus, Dell, Toshiba and MSI.Spectrum of 20 MHz can enable BWA telecom companies to offer service packs for subscriber speeds of 512 kbps, 1 Mbps, 2 Mbps, 4 Mbps, 6 Mbps and 10 Mbps with monthly, limited and unlimited downloads. Subscriber service pack prices could vary from Rs 450 to Rs 600, Rs 900, Rs 1,200, and up to Rs 1,500 depending on the level of usage and quality of service/ quality of experience commitments. BWA telecom companies that have 20 MHz spectrum can serve about 25 to 35 million subscribers in the next three years in the service mix mentioned above, conforming to Telecom Regulatory Authority of India (TRAI) subscription guidelines. BWA telecom companies can break-even in the third year at the indicated capex, device prices and revenue levels, if they can exploit the existing passive infrastructure sharing guidelines of DoT/TRAI.

Santosh Sinha
Both Wi-Max and LTE technologies are suitable for mobile broadband in India.LTE has some technological advantages on account of its higher speed and greater convergence. Wi-Max, on the other hand, is more standardised and is already being adopted by many countries.

How do the two technologies compare in terms of the investments required?
Parag Kar
The economies of scale that 3G offers makes it a more cost-effective mobile broadband solution and enables lower device costs as compared to Wi-Max. 3G networks require fewer sites due to operation in lower frequency bands, which also significantly lowers network expenses.LTE leverages 3G's scale and ecosystem and layers incrementally on 3G, thus offering an attractive future-proof investment for operators.

On the other hand, most Wi-Max deployments are of small scale. Wi-Max also requires more sites as compared to 3G, whether in coverage-limited or capacity-limited scenarios. Commercial Wi-Max networks are in their infancy and require costly expansion to provide adequate coverage.

Purushothaman K.G.
The operators have had to pay an unexpectedly high fee for obtaining BWA spectrum. Therefore, in order to ensure reasonably good returns on investments, BWA operators are exploring all possible avenues. For instance, Reliance will now have to enter into discussions with vendors that offer similar technologies in other countries. To put things in perspective, while the CPE cost for Wi-Max was in the range of $50 to $80 at the time of its launch a year back, CPE costs for TdLTE could range from $150 to $350.

C.S. Rao
I believe that competing technology players are not even indicating the price levels for infrastructure equipment and devices to BWA companies, as they do not have any commercial-grade offerings other than prototypes and some pilot models. The biggest fact is that in 2.3 GHz, Wi-Max has more than 60 commercial-grade networks serving about 10 million subscribers across different continents as compared to the competing technology which has only a few demo projects of 2 BTS to 10 BTS sitebased networks in one or two countries.

Santosh Sinha
LTE requires greater investment as it has not yet been deployed on a large scale and, therefore, standardisation of commercial equipment is yet to take place.

What changes will operators need to make in their existing architecture to deploy LTE or Wi-Max?
Purushothaman K.G.
LTE is an extension of GSM technology.So, the changes to be made in the network architecture will essentially depend on: whether the existing network is fibre, internet protocol (IP) or time division multiplexing (TDM); the core network of an operator; and whether the operator would facilitate 3G tunnelling through it.
If an operator intends to launch LTE in order to integrate it with existing 3G networks, the cost will be slightly higher. But it will offer better flexibility due to the integration of data services with the operator's voice offerings.

C.S. Rao
Radio access network: BTS sites need to be upgraded with the deployment of 4G Wi-Max radio and Wi-Max smart antennas. These sites also need to be upgraded to have digital microwave capacity of at the least 155 Mbps radio and/or fibre backhaul connectivity to the cell site.

Backhaul/EDGE network: An EDGE router having access service network functionality needs to be established in the operator's router-based IP infrastructure.

Core network: IP core network element supporting connectivity service network functionality needs to be established.

Operation support system/Business support system: Subscriber provisioning and billing systems to support broadband service delivery need to be upgraded.

What are the international trends with regard to the two technologies?
Parag Kar
LTE has strong and growing industry support, with commitments from global ecosystem partners -­ including operators, chipset vendors and equipment suppliers.
Eighty operators have made firm commitments to deploy LTE networks in 33 countries, and 22 LTE networks are expected to be in service by end-2010, according to the GSA. Globally, Wi-Max is on a decline. Most Wi-Max networks have failed to attract subscribers in large numbers, and many Wi-Max operators are scaling back their deployment plans.Several major vendors have reallocated their R&D resources to LTE.

Purushothaman K.G.
In terms of international trends, in the US market, two of the largest operators -­ Verizon and AT&T -­ were the pioneers or proponents of TD-LTE technology as compared to Sprint, which was into WiMax. In Europe, the trend is more towards Wi-Max. However, operators are gradually reconsidering TD-LTE as there have recently been certain successful TD-LTE launches in some countries.In the Southeast, there has been a delay in the launch of TD-LTE technology due to regulatory requirements, especially in Taiwan. In China, China Mobile has expressed its intention to opt for TdLTE, and this has been generating interest in India as well.

C.S. Rao

•  4G Wi-Max would be upgraded to WiMax Rel.1.5 and Wi-Max Rel. 2.0 versions.
•  These upgrades support better spectral efficiency, better throughputs, better coverage and better NW capacities.
•  Devices supporting triband devices on 2.3 GHz/2.5 GHz/3.5 GHz and wider RF channels of 20 MHz would hit the market from mid-2011 onwards.
•  More and more multimode devices supporting GSM + Wi-Max and CDMA + Wi-Max would be launched soon, as has been done in Korea, Russia, Saudi Arabia and the US.
•  Peak sector downlink throughput over 350+ Mbps is possible on increased mobility of up to 350 km per hour on Wi-Max Rel. 2.0.
•  On a 20 MHz channel and 4 x 4 MIMO with TDD ratios of 5:3, one sector peak of downlink speeds of >170 Mbps and uplink speeds of >90 Mbps will become a reality by mid-2011. Multi-carrier support is also possible in Wi-Max Rel. 2.0 and bandwidth of up to 100 MHz (over 1 Gbps) downlink is possible.
• Significantly increased VOIP capability would also be there.Competing technologies like TD-LTE would have similar features in the future (by 2013) due to the time lag it had in technology evolution.

Santosh Sinha
LTE is a new technology compared to WiMax, which is already being adopted by many countries.