One must subject oneself to one’s own tests that one is destined for independence and command, and do so at the right time. One must not avoid one’s tests, although they constitute perhaps the most dangerous game one can play, and are in the end tests made only before ourselves and before no other judge. Not to cleave to any person, be it even the dearest—every person is a prison and also a recess. Not to cleave to a fatherland, be it even the most suffering and necessitous—it is even less difficult to detach one’s heart from a victorious fatherland. Not to cleave to a sympathy, be it even for higher men, into whose peculiar torture and helplessness chance has given us an insight. Not to cleave to a science, though it tempt one with the most valuable discoveries, apparently specially reserved for us. Not to cleave to one’s own liberation, to the voluptuous distance and remoteness of the bird, which always flies further aloft in order always to see more under it—the danger of the flier. Not to cleave to our own virtues, nor become as a whole a victim to any of our specialties, to our ‘hospitality’ for instance, which is the danger of dangers for highly developed and wealthy souls, who deal prodigally, almost indifferently with themselves, and push the virtue of liberality so far that it becomes a vice. One must know how TO CONSERVE ONESELF—the best test of independence.

by Friedrich Nietzsche


Life is a great leveler. It extends, bends and pretends.

What you bring along is long tested. What you do not, does not. Uncertainties of nature and existence never have answers. They spring upon us, show us their strengths and disappear, oblivious to what they leave behind. Sufferings are eternal and perpetual. They live with us till we count our last.

Oblivious of what the consequences be at the time of an adventure, experience and incident, it is disturbing to us mortals what lies in store either way. What may seem insurmountable, finds a conquest. What heights we climb, poses another peak to be achieved.

Those that live in constant excess, I believe, are most aware of its fragility. Those that do not, are either fearless or unaware of its crumbling.

Some of us live in constant fear of the consequences, and some have diligently worked out options, were there to be a situation. I would presume that many presume that this option does not exist in most. But it does. And it does in numbers and the thinkings of those that value outcome. There are many that do not, which is fine as a way chosen by them on their own conduct. But many do, and they need to be followed and observed with care.

Excesses attract, irrespective of their genuineness. They are rare and endangered species. They shall always seek to be protected, because. But the world and the universe is not likely to be enamored by them that despite its worthiness and ingenuity, flaunt it with unrestricted pride and arrogance, centimeters distanced, from the nostrils of the lesser.

Many believe that living in the constancy of such thought, deprives one of a freedom. A freedom that is truly our birthright. Fine. I do not have an answer to that which harbors such. But each birthrighted freedom has to be won and labored for, and on its final achievement, to be best rested, within the confines of our ethics and ethos.

Each ethos and ethic has its own parameters, both individually and collectively. They will differ. They shall possess different and varied interpretation. But irrespective of any, they shall all saunter down to one commonality. That common thread is what shall bind us all, in order and command. The observance of this command, this regimentation, if you may wish to address it so, is the desired conditions for behavior.

Character belongs to the ethos and ethic of our growth. With character come dignity. And with dignity, wisdom.

May we all strive to be wise, just, and in belief.

Character belongs to the ethos and ethic of our growth. With character come dignity. And with dignity, wisdom.

May we all strive to be wise, just, and in belief.

Belief in perception is a boon and a curse. The race between reality and its perception, is one that has pervaded our ethos. Wise are they that can project convincingly, reality, before perception overtakes it. For, the latter has habitually been that, which has found belief earlier than the former.

Many distinguished intellect have commented through the ages of the virtues of both, but emphasized the complexities of the latter. One reason then, why it needs greater attention and concern.

Perception shall always require greater care and address. It has the capacity to be of lasting impact. Any impact that lasts, is reverential in its construct. It may not be what it is meant to be. But then meanings in such situations possess alternate meanings as well.

Who and what then to believe ? Which to take as definite ? And why ?

Questions !

Questions need answers. Answers need convincing ability. Convinced ability is another rarity. In today’s most cynical atmosphere, it has a short life.

Best then .. to beat it much before by that which is real.

Nothing in life is achieved without struggle !

Taken from http://srbachchan.tumblr.com/      Day 2150



Finally, much awaited result has come.  Outcome of the final result is not what I worry about, but the uncertainty.  Anyway, now the uncertainty has vanished.  Of course, there is little anguish, I am after all human being like everyone is…

I am not very certain of how much the uncertainty is in Heisenberg principle.  But uncertainty in my recent times have been enormous.

By looking at the outcome, I set myself thinking that, am I in wrong place, wrong situation? What could be the reason/reasons for such result.  Or, did I choose a wrong person…wrong things…or I just don’t deserve….am I expecting too high? expecting too high is no harm, but if you fail in achieving it, you shouldn’t go crazy…

Everyone has something either this or that….me? clueless….

Maybe this is called life..! 🙂

Anyway, If flapping of a butterfly can possibly change the atmospheric conditions (may be a reason for tornado), then why not my work change the future.

Wow, Awesome discovery



Simulated Interference Cancellation and Block Modulation (ICBM) coded and uncoded BER with the precoders designed in A’s paper.

Compared ICBM with reuse1 and found that reuse1 performs better than ICBM (by then end of January).

After this work.

And due to my foot in mouth diesease, I raised a question to Prof. G why not we try 3D constellation, and he asked me to work on Multidimensional constellation, which in the beginning seemed interesting but I could hardly find literature on the Multidimensional constellation which I wanted to learn. So, I lost hope in it and gave up.

From here,

My work got parted in many ways, first I was told to design precoders using ICBM paper for 2Rx antenna (SIMO) as the maximum SpAC for 2Rx antenna is 3/4. I tried designing precoders for SIMO using ICBM paper, but I did not find that work interesting, and also I was apathetic in working on it.

Then I leafed through few papers on Space Time Code blocks, and literature on Spatial Modulation which I found very interesting. But I could not find ways to interlink this Spatial Modulation scheme to ICBM.

Dr. H (Ph.D student) told me to come up with precoder design which is a function of channel (ICBM and B-FIA precoders are not a function of channel) for some other schemes which Prof. G suggested, so after thorough search in literature on precoder design, I found a paper exploiting maxizing channel cut-off rate to design precoders in contrast to many papers which exploit Mutual Information as the basis.

I initiated working on channel cut-off rate (not clearly understood the concept of channel cut-off rate) which employs steepest descent algorithm for designing precoders. I am not very certain about its optimality though.

Due to illness, and followed by Quizzes my work got further delayed.

After couple of weeks, to understand the channel cut-off rate I approached Dr. A T, his anwer was “Cut-off rate is not an elegant way to design precoders but try using something like Outage”. Approaching Dr. A P I got clear understanding of channel cut-off rate, and also superficial understanding of outage probability, and the way it is used in designing precoders.

But none paid heed towards it.

I met Prof. G along with Dr. H almost after two weeks, Prof. G then told me to work on intermediate scheme of FIA and B-FIA, and also SIMO case of FIA. FIA uses complete channel information and it is designed in FIA paper for SISO and MIMO. B-FIA, unlike FIA doesn’t need any channel state information. By name itself it is “blind”. But the SpAC ( Symbols per Antenna per Channel use is less in the case of B-FIA in comparision to FIA).

So, now I gotta design precoders with partial channel state information at the transmitter based on the SpAC value. I suppose SpAC with partial CSIT would lie somewhere between SpAC value with perfect CSIT and no CSIT.



Life is what happens while we are busy making plans.  That’s indeed true.  Life is not what many say it is, it is a lot more wise.

I have been getting hit with many hard surprises in recent times.  I do not know how to react but to just remain passive, calm and accept it.

Lamenting or being remorseful is never a solution to any hard surprises.  All I need to do is to just accept, take the life as it comes…

Everything will be alright, maybe not now but eventually will be…..

Are those surprises for good or for bad? or am I unnecessarily bickering myself…

Time will answer everything…

let’s be strong and have faith.



It’s almost the end of February, but there has been no clear response yet.

What my life would be after 4 months is still an enigmatic and elusive.  Flummoxed with my current position, not been able to concentrate on other things properly…

Being very tardy in my work at present, and also almost shunning away the things that come across…

Yet, I always try to confront the situations with fortitude but nevertheless at times I get distraught…

Hope is actually a good thing, but my situation is like hoping against the hope.

My mind always sets a question that would I continue doing research in cutting edge and pursue my interests in research career in wireless communications/networks or would I just end up doing something in disdain…

As always should try to avoid being stampede and maintain peace and calm……..!



Have been suffering with severe sore throat, and fever.  Beside this, have many challenges to face.  Have gazillion papers to read and work on my project.  It’s been a tough week before many stumbling blocks ahead.

Life is becoming more and more erratic, and chaos.  Not knowing where I would stand after four months.

Interested in doing cutting edge research in wireless communication/networks, and also wanted to incubate a company during the process.  But the conditions and complications I come across doesn’t allow me to do so.

The worst thing that happened to me is having bit too low GPA, which stops me always in dictating my research interests.

Currently, suffering with two problems.  One is sore throat which perhaps will alleviate in couple of days, the other is my research.  The problem in the latter keeps on escalating as the days sped.

Anyway, all I can now do is just wait and watch…..

Need to learn being patient……….

Have read this somewhere “Good things happen to who wait”

Let come what may…………………


GPON, Uncategorized

Optical fibers have the capacity of 25 Tb Hz of bandwidth, which is almost 1000 times greater than RF (radio frequency) bandwidth.  Light is kept in the fiber core by total internal reflection.  This makes the fiber act as wave-guide.

Optical Fiber is used in Telecommunications as a medium/channel to carry the information.  The information can traverse long-distance as the attenuation of the signal/information is very less which in contrast to the information traversed using RF.

Each Fiber can carry multiple channels using different wavelengths of light, this is called as Wavelength Division Multiplexing (WDM).

total internal reflection in an optical fiber

PON (Passive Optical Networking) is connection from one point to multiple points (P2M) using an optical splitter which is passive ( which does not consume any power) splits the signal into 2,4,8,16,32.. directions.  A PON consists of an OLT (Optical Line Terminal) at the service provider at the central office and  ONU (Optical Network Unit) which is a collection of ONT’s (Optical Network Terminal) at the consumer end.

The word GPON which is Gigabit Passive Optical Networking is evolved from BPON (Bandwidth Passive Optical Networking).  Gigabit is the speed/rate of the information carried on the Fiber i.e., the rate of the information is in GigaHertz….

The data is transmitted from OLT to ONT i.e., in downstream as a broadcast manner but encryption (AES) Advanced Encryption Standards is used to prevent eavesdropping and as TDMA manner from ONT (users) to OLT.

At ONT the light (optical signal) is converted into electrical signal.  Each ONT has many ports like say Ethernet, VOIP, IPTV, etc i.e., a single fiber at the end user provides many services.  It is usually referred as FTTU/FTTH (FTTX) fiber to the user/home.

GPON key technology.

OLT identifies ONT’s using ONU-ID (Identifier) which is 8 bit identifier and it is unique.

ALLOC_ID is a 12-bit number that the OLT assigns to an ONU to identify a traffic-bearing entity that is a recipient of upstream bandwidth allocations within that ONU. This traffic-bearing entity is also called T-CONT.

A Transmission Container (T-CONT) is an ONU object representing a group of logical connections that appear as a single entity for the purpose of upstream bandwidth assignment on the PON.

will keep posting more…


The Lorentz attractor is generated by a set of differential equations which model a simple system of convective flow.  In a paper published in 1963, Edward Lorentz demonstrated that this system exhibits chaotic behavior when the physical parameters are appropriately chosen.

The Lorenz system is deterministic, which means that if we know the exact starting values of  variables then in theory we can determine their future values as they change with time. Lorenz demonstrated that if we begin this model by choosing some values for x, y, and z, and then do it again with just slightly different values, then you will quickly arrive at fundamentally different results. In real life we can never know the exact value of any physical measurement, With these results, Lorenz shocked the mathematical and scientific community by showing that a seemingly nice system of equations could defy conventional methods of prediction. This is called chaos, and its implications are far-reaching, especially in the field of weather prediction.

The Lorenz attractor is an example of a strange attractor.  Strange attractors are unique from other phase-space attractors in that one does not know exactly where on the attractor the system will be.  Two points on the attractor that are near each other at one time will be arbitrarily far apart at later times.  The only restriction is that the state of system remain on the attractor.  Strange attractors are also unique in that they never close on themselves — the motion of the system never repeats (non-periodic).  The motion we are describing on these strange attractors is what we mean by chaotic behavior.

The set of equations describing this behavior are:

x’ = σ(y – x)
y’ = x(r – z) – y
z’ = xy – bz

where the three parameter  σ , r, b are positive and are called the Prandtl number, the Rayleigh number, and a physical proportion, respectively. It is important to note that the x , y , z are not spacial coordinate. The ”x is proportional to the intensity of the convective motion, while y is proportional to the temperature difference between the ascending and descending currents, similar signs of x and y denoting that warm fluid is rising and cold fluid is descending. The variable z is proportional to the distortion of vertical temperature profile from linearity, a positive value indicating that the strongest gradients occur near the boundaries.

when σ=10, r<1, and b= 8/3 is chosen the plot look like this


when σ=10, r=1, and b= 8/3 is chosen the plot look like this


when σ=10, r>1, and b= 8/3 is chosen the plot look like this


when σ=10, r=28, and b= 8/3, the Lorenz system has chaotic solutions (but not all solutions are chaotic). The set of chaotic solutions make up the Lorenz attractor, a strange attractor


The Lorenz attractor is difficult to analyze, but the action of the differential equation on the attractor is described by a fairly simple geometric model.