Introduction :

Hello everyone, good afternoon. I'm RK. I completed my master's from one of India's leading institutes, IIT Kanpur, and currently, I'm working at Qualcomm Pvt Ltd in Hyderabad in the field of wireless communication. My master's courses and thesis were focused on wireless communication, and now I'm working on the Wi-Fi module and its firmware. I'd like to share with you the key subjects, tools, projects, and experiences that can guide you if you're interested in wireless communication.

Key Subjects in Wireless Communication :

Starting from the basics, one of the foundational subjects is Signals and Systems. In Signals and Systems, we specifically focus on Digital Signal Processing (DSP), which is crucial for wireless communication. In DSP, we deal with a lot of Fourier transformations, time-domain analysis, and frequency-domain analysis. These concepts are very important in that subject.

Another important subject is Digital Communication, which involves understanding how encoding happens, how we transmit data, and what is the sampling rate and Nyquist rate. All these things are related to communication, so that is also important in the communication part.

Coming to Wireless Communication, we deal with practical scenarios where we have multipath interference and all these things that take place in modern cellular communication systems. So, in wireless communication, it is like practical system design of how the solution works.

Then, we have advanced topics like MIMO (Multiple Input Multiple Output). MIMO and technologies like 5G and 6G are key aspects that are revolving around wireless communication right now. This technology has enhanced cellular communication, and even in Wi-Fi systems, these are now in the advanced stage. We have different new protocols that are introduced in these technologies.

In our college, we had a 5G Simulation course, where we used to study all the five-layer functionalities. In that, we have a lot of PDCH (Physical Downlink Control Channel) chains. So, those are the things we mostly see, and these are the implementations that are practically done in the wireless domain itself.

From the mathematical perspective, Linear Algebra and Probability are important things. Some topics related to Statistical Signal Processing and Estimation and Detection Theory are also important regarding wireless communication. Even for Digital Signal Processing, these things are important.

Key Topics Within the Subjects :

In Signals and Systems and Digital Signal Processing, we focus on Fourier Transformations. A lot of time-domain analysis and frequency-domain analysis are very important in that subject. Understanding how to switch between these domains is crucial because some problems are easier to solve in one domain than the other.

In Digital Communication, we learn about how encoding happens, how we transmit data, and what is the sampling rate and Nyquist rate. These are key concepts in digital communication. They help us understand how to efficiently and accurately transmit data over communication channels.

In Wireless Communication, we deal with practical scenarios like multipath interference, which occurs when signals take multiple paths to reach the receiver, causing interference and signal degradation. We study how to mitigate these effects and design systems that can handle such challenges.

MIMO technology involves using multiple antennas at both the transmitter and receiver to improve communication performance. It increases capacity and reliability in wireless systems. This is especially important in modern systems like 5G and 6G.

In our 5G Simulation course, we studied the five-layer functionalities of cellular communication systems. We worked on projects involving the PDCH chains, which include various blocks like scramblers, LDPC (Low-Density Parity-Check) coding, rate matching, CRC (Cyclic Redundancy Check), and others. Implementing these blocks helps us understand how data is processed and transmitted in real systems.

In Statistical Signal Processing and Estimation and Detection Theory, we learn how to detect and estimate signals in the presence of noise. We use different approaches like hypothesis testing, Maximum Likelihood Estimation (ML), Minimum Mean Square Error (MMSE), Linear MMSE (LMMSE), and Singular Value Decomposition (SVD). These concepts are practically used in wireless communication for tasks like channel estimation.

Tools and Programming Languages :

When dealing with the PHY layer, we mostly perform software simulations. For system design and testing methods like OFDMA and MIMO, we use MATLAB for simulating all these things because it has a lot of libraries related to cellular wireless communication. It helps us use reusable codes in that, so that is one of the good tools that we use.

Coming to the basic work, we use programming languages like C and C++. A lot of embedded programming is involved, where you have to interface with hardware interrupts and all these things. There are C++ programming and C programming mostly because a lot of memory utilization is there. You have to figure it out using pointers and dynamic pointers and all those things.

Other than that, Python tools are also used for mathematical calculations. Python has good libraries related to mathematical computations. We use Spyder, which is an IDE for Python, for simulating a lot of random processes. In wireless communication, we deal with random interference and noise, so we use these libraries for simulating all the scenarios. These tools are mostly used in the market also.

Recommended Projects :

In terms of projects, hands-on projects help students build their understanding of key subjects and topics.

Specifically, wireless communication systems are very complex. It's not like you'll be able to implement the end-to-end system, but there are practical aspects you can focus on. A lot of things we do theoretically are on ideal cases, but in practical environments, we have a lot of cell towers and interference.

For example, in my MIMO Communication course, we had a project where we analyzed a two-cell system. We calculated the inter and intra symbol interference. These are theoretical derivatives. We first derived them mathematically—the theoretical things—and then we implemented this in code to analyze the theoretical and practical examples.

In Digital Signal Processing, there are a lot of things like Fourier Transform that we use for correcting noise. If you want to remove noise from a time-series signal, you use your Fourier transformations and all those things. These small projects help you understand why we use Fourier Transform, why we are not able to correct noise in the time domain but can refine it in the frequency domain.

Coming to a very major project in wireless companies, it needs a lot of guidance. It's a theoretical impact only you have to use, but just creating a scenario of a random thing and then utilizing that will help you to make it more understandable that your theoretical curves and the practical curves are aligning.

In our 5G Communication course, we worked on the PDCH chain, which is the Physical Downlink Control Channel. There are a lot of blocks before sending the data in the PHY layer. In the PDCH, we implemented all the blocks like scramblers, LDPC coding, rate matching, CRC checks, and these things were there in the blocks. Once you have the theoretical understanding, you will get to know how to use this for implementation in the PHY layer and just code it out and check what's the result and all.

By implementing these kinds of projects, students will get to know about the topics and in what matters. They will see the practical impact of why we use Fourier Transform, why we are not able to correct noise in the time domain but can refine it in the Fourier domain. These things you can do with simpler simulations also, but you will get a good understanding of that. But mostly, the theoretical part should be clear; then only you can implement this in the simulation.

Preparation for Job Interviews :

Regarding job interviews in the wireless communication field, the preparation should be aligned with the subjects I mentioned earlier. In interviews, they mostly focus on mathematical things like Linear Algebra and Probability because a lot of linear algebra and probability concepts are involved in wireless communication. So that is one thing.

Then, they will ask about Digital Signal Processing. DSP is a very important topic about Fourier Transformations, sampling, Nyquist rate, and why we do what we do. Why is it important in wireless communication and cellular communication? These things are very important.

Thirdly, in wireless communication, there are a lot of analyses, like how to mitigate inter-symbol interference and concepts like MIMO and OFDMA. These are mostly important in wireless communication because they are the key of new generation communication systems. They may not ask very advanced questions, but they ask basics. There are a lot of tricks and case scenarios that you should be aware of; that will help.

Apart from that, basic programming you should know, like related to C++, pointers, and all these things that are used for implementation. Then they can ask related to some operating systems concepts also, like interrupts and all these things sometimes they ask. But mostly, they concentrate on these topics that are the core subjects themselves.

Understanding Case Scenarios :

As I mentioned, in Estimation and Detection Theory, we study scenarios involving detecting signals. So that signal comes with noise in it. How to detect that signal? We have different approaches for detecting that signal using hypothesis testing.

Estimation of the signals is also one of the things. You have a signal that gets buried in some noise. Now, you have to estimate that signal. You use different approaches like LMMSE (Linear Minimum Mean Square Error), MMSE (Minimum Mean Square Error), ML Estimation (Maximum Likelihood Estimation), and all these things. These scenarios are practically used in wireless communication also.

We have blocks in the hardware itself that calculate these things. Even for channel estimation, we have methods like SVD (Singular Value Decomposition), ML Estimation, LMMSE, MMSE, etc. All these blocks are there in the hardware itself. These things help you to get more ideas for these algorithms and scenarios. But there are a lot of scenarios—uncountable in terms.

Job Roles in Wireless Communication :

In the industry, there are different job roles available in wireless communication. Layer-wise departments are also there.

• PHY Layer: I work in the PHY layer, which is the last layer in cellular communication where we do all the encoding and processing. Whatever modulation you are using, whatever scheme you are using for transporting data—that is one device that we call as a Firmware Engineer. That is one of the profiles.

• Testing Profiles: We have testing profiles also, where we test different scenarios. There are test teams in the company. All the communication companies have some test teams that simulate all these scenarios. They test all these algorithms.

• MAC Layer Team: We have the MAC team that works on the MAC layer. So, dealing with all these things is done in the MAC team.

• RF Teams: There are RF teams that are at the end, better for enhancing energy efficiency and those things.

So, there are layers of blocks that are there. For every block, there is expertise. But overall, whatever from the freshers, they may have general knowledge of it—whatever in the subjects I told. Other than that, you will get these things on the job.

In Qualcomm, where I work, we have Systems Teams, Firmware Teams, and Testing Teams. Systems teams are responsible for designing the algorithms so that it enhances the performance of the communications. Firmware teams use these algorithms and implement them in a practical aspect because they work on theoretical parts only. Firmware works on how the board gets calibrated; all these things are done with firmware. The test teams test whatever algorithms we have implemented. These three teams go hand in hand; they're not in silos.

Opportunities and Industry Trends :

Regarding opportunities available in the market for wireless communication people, it's true that not many companies are working exclusively on wireless communication. But there are ample opportunities in wireless also because wireless works on embedded systems itself.

Embedded profiles are also there for wireless communication because you work on hardware blocks only. Whatever implementations you are doing are implemented in the hardware blocks. That work you get to know in wireless communication itself. So, that is one profile people switch to.

The only part that changes is that you are working on wireless things. But in other profiles, there are IoT Embeddeds, some other firmware related to CPU embedded work. So, only the hardware blocks get changed, but the process of programming is the same. Only the documentation changes—how this hardware will work. They have other things to be handled.

But overall, there are a lot of opportunities in wireless. You will get a lot of ideas about hardware and firmware in this. So, it's all about the interest that you want to pursue. But core wireless companies are less, that I can say, and even then, there are good things in wireless companies.

Bridging the Gap Between Academics and Industry:

Now, how much is the gap you feel between whatever you have learned and what you are working on now as a PHY layer engineer and firmware engineer? There is always a gap between, I could mention, the company's culture.

In academics, we mostly focus on theoretical aspects—how this came into picture, how we are using it. But in companies, there are lots of complications in the practical aspects—how it is getting implemented. This gap is always there, and that goes down after you work in some company only because you don't know the different sets of instructions and different protocols they follow.

But you have an idea of the technological concepts from the theoretical side, which will help you in doing the practical aspects. So, that is always interlinked. It's just a learning part of how you implement it because here, we actually cater to our customers. That is for practical use that has to be done correctly because it is in day-to-day use.

Academics give us the understanding of how and why we are using all those stuff in the practical. The company gives an idea about how practical work is done.

Entry Points in the Industry:

Are there entry points in the industry for wireless communication? Do you see students pursuing testing, PHY design, or system design after their master's? For that, should you have a master's only, and in the master's also, should you be from the premium institutes like IIT Kanpur, or is entry possible from other institutes?

Basically, it revolves around the knowledge that you are gathering. This knowledge is now available on YouTube and courses, but these things are not that much in practice in the market itself. So, people used to do master's in that. In master's, we study specifically for these things, so that helps.

But even after B.Tech, if you study all these things and try for a company, if you know things, they do not care about your degree level. For the premium institutes, yeah, you will get a little bit more opportunity there—easily approachable, like companies that are coming for core things. But for off-campus and all, it takes time, but I think patience helps.

I've seen examples of students coming from bachelors and working in our field, and students coming from masters but from second-tier and third-tier universities. A lot of people are there who are working on that; they are good at their work. Sometimes their past experience also helps. If you have worked on some embedded things before, it's very easy for you to switch to wireless communication because you just need to get the documents of how wireless communication works.

It's only about the knowledge that you have. Whatever they require, if you have that thing, then it is easy for you to get.

Industry Requirements :

What exactly does the industry require? For core wireless, you need wireless communication knowledge—that is the most important thing. Whatever courses revolve around this wireless communication, from the basics to the advanced, you have to know these things, like whatever I mentioned in the subjects. That covers all the topics.

These are the entry-level things they look for. If you know those things and get an opportunity, they will mostly focus on those aspects. That is the only requirement for getting into this domain.

Switching Between Embedded Systems and Wireless Communication :

If you want to switch from embedded to wireless, embedded gives you experience of how hardware and software interfaces work, so that you already know. Now, you have only to study what wireless blocks have—why in wireless communication, what blocks are doing.

For channel estimation, we have different blocks like SVD, MIMO, MMSE, and all these things we do. These blocks are there in the hardware itself. So, their functionality at the end—whatever we are doing in the theoretical aspect—has to be coded into the board itself so that they can analyze.

That is just a transition from embedded to wireless. For wireless people who want to go to embedded, they have the knowledge of the interface between hardware and software. Only the hardware block has changed there itself in embedded. Now, you're not working on wireless blocks; that block is catering to some other purpose.

Other than that, whatever hardware interface is there—we get interrupts, then we have some ISR callbacks, whatever OS-related things that we do practically—that are there itself. So, these all are things common in wireless and embedded itself. That helps you to easily move between these two domains because a lot of people from wireless go to the IoT domain. These things are there.

Experience and Career Progression :

In terms of experience and what people with two or three years of experience are doing, at the entry level, you join as an engineer. There, you mostly work on parts where some modifications go on. So, those things you work on. A lot of debugging things also you work on.

In the practical aspect, a lot of problems come during the customer usage. So, those are the things you figure out because before marketing that thing, we need to resolve all the problems that we face during testing. So, that thing we mostly work on.

If you work for two or three years, you become a senior engineer, and then it goes on like that to lead and so on. As you go up, you will move more broadly into it. Now, if you are working on some singular blocks, and that block gets expanded, you will be working on bigger blocks. These things expand as you gain experience.

At a certain point, like six or seven years, you will be handling a target itself. The target is like whatever chip—for example, we've heard about Wi-Fi 6, Wi-Fi 7, Wi-Fi 8—so these are different packet types. You will be owning all the things that are there.

This ownership expands with experience. And it also comes with managerial aspects; you will be managing people also to work on different blocks because all blocks are integrated. You will be at the outer of the block, and you will be monitoring all the blocks inside that, how it is working.

Choosing Industry vs. PhD :

Many people in wireless communication pursue PhD and then postdoc, but I chose to go into the industry after my master's. Why? Because I was interested in the practical aspects. One of the reasons is that, from my perception, the difference between PhD and working people is like PhD works on the technology itself—they work on the advancement of the technology—while corporate people work on implementing that thing. So, that is the difference I classify between them.

I was more focused on practical aspects. I was interested in this embedded profile and wireless too. So, I was more keen to get into this practical aspect of how it works and all those things. So, that's why I joined the corporate world.

PhD is also a good option because it gives you a lot of opportunities in the exploring domain. Whatever new technologies are there, a lot of analyses are done by PhD researchers themselves. They have a lot of analysis. PhD holders also join companies after completing their PhD, once they achieve their knowledge in that domain.

In the corporate world, it is more about how you implement that thing. As you grow in the company, you get to know more about the practical aspects, how it functions in the practical aspect. For PhD, it is more over the technology advancement that is coming.

Peers and Trends :

Regarding the trend among my batchmates, most of them are placed, whoever opted for doing corporate work. They are placed in different domains. Some of them got placed in wireless itself; some were interested in hardware, so they got placed in the wireless domain also. Some got placed in power systems; some are in embedded systems.

So, diverse profiles are there. Some are in Machine Learning (ML) profiles also, ML and signal processing profiles are also there. Some have pursued PhD from foreign universities and in prestigious colleges in India. They are exploring whatever domain they have selected, like if it is an ML profile or signal processing profile or whatever.

So, they have a very diverse trend circle. I can't justify why they chose that, but they liked it, so they pursued it. One of my friends, maybe in IISc itself, joined the PhD there.

Advice to Students :

As advice to students, whatever domain you are choosing, you should first get aware of what things are going on there. That is one thing. One perception I have is that any domain you are choosing, whether it's hardware or software, you have one software simulator everywhere. So, you should know the tools that are used in that domain itself for simulating because you don't implement everything in hardware and check it like that.

Basic programming—you should know things; that is important. Core knowledge about whatever you are doing—that is enough to go into any domain.

Conclusion :

Thank you for your time, and I hope this guidance helps you in your educational journey. If you have any questions or need further advice, feel free to reach out. Have a nice day!