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Wednesday, February 14, 2007
Pravin Prashant
Professor Arogyaswami Paulraj has a dual portfolio. He is a professor at the Department of Electrical Engineering, Stanford University and also CTO & co-founder of Beceem Communications, a leader in WiMax chips. In Stanford, Paulraj supervises Smart Antennas Research Group where focus is on multiple antenna communications. At Beceem, he is involved in building a WiMax portfolio and creating universal acceptability among carriers.
Considered to be the father of WiMax, Paulraj has 25 patents to his name and is awaiting another 11 which are still pending. During his Indian Navy stint, he developed the world's best Sonar called APSOH, successfully deployed in all ships. He was also instrumental in starting 3 labs-CAIR, CDAC, and BEL Central Research Laboratories.
In 1998, Prof Paulraj founded Iospan Wireless that was acquired by Intel. He was also co-founder Arraycom where MIMO was developed during one of the experiments, and is one of the three building blocks. In an exclusive interview with VOICE&DATA, Prof Paulraj talks about WiMax technology and its future. Excerpts of the interview:
What promise does WiMax hold in the broadband space?
WiMax is the first of a new class of based on modern ideas of MIMO (multiple input multiple output), OFDMA (orthogonal frequency division multiple access) and OS (opportunistic scheduling). All new are based on these ideas and even 3G PP and 3G PP2 are based on MIMO, OFDMA and OS.
WiMax has an advantage vis-a-vis others as it is the first to bring hardware products and is almost two years ahead of the others. It is based on a sound technology and has the support of many players and device manufactures. There is also a lot of momentum in terms of chip development, equipment, and CPE. A lot many trials are also happening in each area giving it a lot of confidence. There is a great demand for broadband at home as well as office, and the developing world definitely needs broadband at home; WiMax supports sub notebook and tablet applications. So, WiMax has the right ingredients and is also the first in the market.
Even on the IP (intellectual property) part, the WiMax cost structure is much lower than CDMA (which is weighted in favor of Qualcomm) and is almost similar to GSM. And for IP, GSM is a good model to follow.
Which technologies are similar or equivalent to WiMax?
On the GSM side it is 3G PP LTE (long term ) and on the CDMA side it is 1x Rev C. The other two come from a strong history but WiMax is a new kid in the block.
The LTE standard is expected to be announced in 2007 or 2008. 1x Rev C is based on 802.20, which is based on IEEE but they had legal problems and had to abandon it, and renamed it as MediaFLO.
All these technologies are virtually identical in nature. They will merge or remain separate-it is more of a political and economic decision.
How do you see WiMax as a superior broadband technology?
In the case of WiMax there have been bottleneck at all levels, right from the start. But things are moving smoothly, the standard for WiMax is fully defined. The WiMax profile has evolved. Vendors have built products, and carriers are also supporting. All big names like Sprint, SKT, KT and SingTel have announced their plans. SKT is planning to deploy and SingTel is deploying broadband using WiMax. KT is planning a 600 base stations network. So, all bottlenecks have been overcome and the only key thing remaining is a widespread trial by a carrier.
There have been a lot of trials on the fixed side as it can be deployed quickly. On the mobile front, it will take some time as it is complex. Sprint is planning for a two-city WiMax deployment in 3Q 2007 and has given the contract to Motorola and Samsung.
What is the evolution path for WiMax?
In 2007, we will see the deployment of 16(e) technology. In 2009, we are expecting the next revision in terms of 16(m). MIMO is presently at 2*2 level we are planning for 4*4. Since Wi-Fi has gone for 4*4 so WiMax also has to follow the same.
In terms of cost, how is WiMax placed?
WiMax is at a lower cost in terms of core as it is a Unix server and all interfaces are open, and IP is as per GSM. Cost of baseband is 30% and cost of CPE is also lower.
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Even on the IP (intellectual property) part, the WiMax cost structure is much lower than CDMA (which is weighted in favor of Qualcomm) and is almost similar to GSM |
What is the ideal band for WiMax in India?
700 MHz is good on range but loses badly on mobile. For rural and fixed network, 700 MHz is ok for voice. For converged operations, mobile band is best ie 2.3–2.5 GHz. In the urban environment, it is either mobile or fixed so it is 2.3–2.5 GHz. 2.3-2.5 GHz wins over everybody.
For WiMax one requires the 10 MHz band; in some countries it is 5 MHz. Presently, 10 MHz is the main momentum, 20 MHz will come later.
With respect to spectrum, US operators were asked to move to a different spectrum to accommodate large number of users. And even carriers can fund the transition to use spectrum for widespread public use. India can opt for this in the case of WiMax.
What are the areas of research where Indian companies can focus on WiMax?
The most important part of the phone is the chip but we do not have R&D strength and we are not playing in the fundamental layer. Next is the box level where there are big players like Nokia, Motorola and Nortel. And here also there are no Indian companies. The things that we do well is network installation and operation but in WiMax, India should take a lead and be equal to countries like the US, Japan, and Korea.
In 1992, Europe was going ahead in wireless and in order to promote wireless, the US government gave free spectrum to companies innovating wireless technologies. So, the Indian government has to take a lead and create initiatives for the private sector to enter. Say by giving free spectrum in one particular state. And all this will help in creating our own IP in WiMax.
India can create 1,000 companies in the WiMax space right from network management, connectivity, application and billing. Even in applications, focus will be on megabits speed in mobile, streaming, gaming, and movie clips. In VoIP there are 50 companies and each has its own differentiation. So, in WiMax, companies have to look for differentiation. And this speed will bring new things as mobile broadband is a revolution that one can't imagine.
What's your opinion about WiMax deployment in greenfield operations in India?
3G spectrum was given on the promise that it will provide broadband access but it has not delivered. 3G is there as people have lots of money and vendors have to sell their products. If the application is voice then stay with GSM. India should not be the ground for system builders to make some profit. India should leapfrog to WiMax and LTE as new technologies are delivering.
There is not a strong case for 3G in India. In 3G one can get average speeds of 350 Kbps for 2 circuits whereas in the case of WiMax it is 10 Mbps for 2 circuits. In terms of spectral efficiency, one gets around 2.5 times 3G.
Pravin Prashant
pravinp@cybermedia.co.in
Source: Voice&Data
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