As all of us experience everyday, we are in an increasingly wired
world. To state it better, we are in an
increasingly wireless world.
Undergirding that is a rapid development in signal processing and
communications technology. Mr. Kamaraj (ECE, 1986) traces his career in this critical area and offers his view on what is at the
forefront of these developments.
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| Mr. Kamaraj (ECE, 1986) |
Introduction:
Electronics and Communications
Engineering was a new and emerging branch of study when I started my
undergraduate program at PSG College of Technology. I am thankful to
Prof. Jayaraman and Prof. Narayanaswamy for triggering my initial interest in
the field of electronic communications.
It was also my dream to
acquire a masters degree from the Indian Institute of Technology (IIT).
However my entrance exam score (GATE) was not good enough to gain
admission. Rather than take up a job, I was determined to pursue my
interest. With the support of my parents, I decided to stay at home and
prepare for my examinations once again.
I succeeded the second time
and I joined Master’s program at the Indian Institute of Technology in Chennai,
specializing in Communication Systems.
ESP on DSP
The IIT curriculum was well
designed and quite advanced, especially in the field of Digital Communications
and Signal Processing.
The field of DSP (Digital
Signal Processing) got more attention with the advent of DSPs(Digital Signal
Processors) and it was around 1983 when the first DSP (Digital Signal
Processor) from Texas Instruments was introduced in the market.
I got the opportunity to
design and implement a low bit-rate (2.4 kbps) MODEM (Modulator/Demodulator)
using the Texas Instrument DSP. This experience triggered lots of interest to
work in core signal processing and communication projects in my career.
A Career in
Signal Processing
My first job was with Indian
Telephone Industries in Transmission Research & Development. The project
was to design and develop an end to end secure communication systems for the
Indian Army. This project involved designing hardware and developing algorithms
and DSP software for subsystems such as speech coders, encryption engine and
wireline MODEMs (Modulator/Demodulators) using DSPs. This was one of the
more complex projects that I had worked on.
Later on at Motorola in
Bangalore, I worked on multiple software projects in DSP and Networking and the
focus was to develop well documented 6 Sigma quality software adhering to CMMI
policies. I had the opportunity to implement V.32 bis(9.6/14.4 Kbps) wireline
MODEMs using a well-defined software process.
Of course,
these days we get data rates up to 100 Mbps through DSL technologies and up to
1 Gbps using wireless technologies.
The algorithms and implementations
to realize this was exciting for me.
A signal
from the United States
ArrayComm was started by
Stanford University graduates. One of the co-founders is Martin Cooper
who is the father of cell phones. I got a job at ArrayComm in Silicon Valley,
California, through a friend.
ArrayComm was founded to
develop smart antenna based WLL (Wireless Local Loop) and long range
wireless internet technologies. The smart antennas refer to the usage of
multiple antennas to transmit and receive signal to improve the capacity and
range of the wireless system.
A simple analogy to smart
antennas is how the brain combines the acoustic signal received through two
ears, the smart antennas employ multiple antennas to combine the received
signals for improving the signal strength. At the same time the smart antennas
help to transmit the signal in a known direction. The smart antenna technology
enables to communicate to multiple users who are spatially separated but in the
same frequency band.
Technology
well ahead of time
Though Array Comm's vision was
great and developed a great technology, it was very futuristic and well ahead
of the market demands for increased data rates. The market did not require the
spectral efficiency during the decade of the 2000s. Whereas the market
necessitates high spectral efficiency and self-adapting wireless technologies
in the decade of 2010.
It is
important for a technology start-up to track the market requirements few years
in advance for it to be successful, not way too much in advance.
For example, OFDM (Orthogonal
Frequency Division Multiplexing) technology which is the defacto standard for
implementing broad-band wireless and wireline communication systems today was
invented in mid-1960s. But no one used the technology until recently due
to lack of fast processors to implement the technology and there was no
requirement for massive broadband communications in 1960s.
Wireless
technology for the future
I now work for a wireless
start up called Tarana Wireless. The company is similar to ArrayComm in
developing advanced broadband wireless communication systems with multiple
antennas. The systems can be used as wireless backhaul (think of a wireless
replacement for ethernet cable or a fiber optic cable) or the system can be scaled
to BWA (Broadband Wireless internet Access) systems, and can be used for
Wi-Fi systems in aircraft to communicate to the ground.
Wireless technologies evolve in terms of self-adapting
the frequency, protocol, and networking parameters to provide a desired quality
of service(QoS). There is lot of ongoing research in cognitive radios which is
essentially cloud based dynamic spectrum management and enabling coexistence of
different wireless devices with different protocols optimally in a given
geographical area.
Cognitive radio and future
wireless technology triggers research areas of:
1. Perfecting RFIC (Radio
Frequency Integrated Circuit) design to operate in a wide range of frequencies
2. Minimizing the distortion
of PAs (Power Amplifier) using DPDs (Digital Pre-Distortion), minimizing the
variation of RF device parameters over a wide range of temperature
3. Sophisticated calibration
procedures to compensate for the RF imperfections, high precision ADCs that can
work at very high sampling rate
4. Configurable processors
integrated with hardware accelerators and a well-structured hardware/software
module development in an automated fashion abstracting the interfaces between
software and hardware
5. Low cost, high density, and
faster FPGAs (Field Programmable Gate Arrays) for quick prototype and product
development
6. Improvement of material
science to perfect the antenna design
7. Cross-layer optimization
between PHY (Physical) and MAC (Media Access Control) to increase the spectral
efficiency further
8. Predictive channel models
using neural networks to predict the wireless channel and optimally transmit
data
9. Cloud based network nodes
for monitoring and optimizing the performance globally
We are rapidly moving to
becoming digital societies across the world. We are moving from being
voice focused to data focused. We are moving from building pipes to
providing content. We are hurtling from connecting people to connecting
machines, through the internet of things.
Most companies will be using
Cloud-based services. Cooper's law states that the number of voice/data
connections has doubled every 2.5 years which means that the average data
requirement is going to be 3.2 GB in 2020, which necessitates a global dynamic
spectrum management and high spectral efficiency wireless technologies to meet
the data requirements.
Summary
Being in start-ups all through
my career, I have learned that it is challenging to continuously learn and keep
abreast of new technologies. It is very important to learn continuously
in the job as the technologies are rapidly evolving and the tools and
infrastructure to develop these new technologies are rapidly changing.
The world always asks,
especially in Silicon Valley, "What can you do today?" and it
does not care about what were your previous achievements, accolades, and
fame. So, everyone has to be prepared to work on the latest developments
as they rapidly evolve. Keeping pace with these rapidly changing
technologies is not just about acquiring and keeping pace with new technical
skills. It is also having a good mindset and a healthy body to sustain
the stamina to stay current and relevant in today’s global and competitive
marketplace
About the
author:
Mr. Kamaraj works for Tarana Wireless as Executive Director, Software.
He lives with his family in Sunnyvale, CA.
Thank you Kamaraj
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