 Hello, welcome to this course on digital communication using GNU radio. My name is Kumar Appaya and I belong to the department of electrical engineering at the Indian Institute of Technology Bombay where I am an associate professor and I teach this subject. Digital communication has unleashed a revolution and in fact you would have observed over the past two decades of how media is being delivered to you, you can essentially get high quality content on your phone, on your TV and on various other platforms and you can make rich calls as well, voice calls, video calls across the continents. In fact, much of the technology that is powering the way this lecture is being delivered to you is also the result of several developments in digital communication. This course will focus on reliable transmission of bits from one place to another. In other words, our focus will be on the physical layer of the communication stack. We will be focusing on how you can send bits efficiently across various media ranging from wired or wireless systems, optical systems and we will also discuss the impairments that you have to overcome, the constraints that you have like bandwidth limitations, power limitations, noise, impact of channels and so on. So we will build this material up from the first concepts but one key differentiator for this course is that we will be evaluating all the concepts and theories that we learned in the software called GNU radio. GNU radio is a free and open source software that allows you to quickly put together simulations for various communication systems. It also allows you to interface with hardware as well so that you can build prototypes of communication systems very, very efficiently. It is cross-platform and very capable and we will be looking at and extending the capabilities of GNU radio as a part of this course as well. This course while primarily targeted at undergraduate students of electronics and communication engineering and related subjects is also applicable for graduate students as well. Industry personnel who are working in communication will also stand to benefit from this course. I hope that you enjoyed the course. Thank you.