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Courses » Spread Spectrum Communications and Jamming

Spread Spectrum Communications and Jamming

About the course

A spread spectrum communication system deliberately spreads the spectrum of the signal beyond the required bandwidth needed for information transmission to achieve resilience against hostile jamming, low probability of intercept resulting detectability to be almost impossible as compared to non-spread signals, inherent message privacy and security, good rejection of multipath signals, high degree of ranging precision (due to the large bandwidth involved), and compatibility with code division multiple access (CDMA) capability. Originally adopted in military networks as a means of ensuring secure communication when confronted with the threats of jamming and interception, spread spectrum systems are now the core of commercial applications such as mobile cellular and satellite communications. The Global Positioning System (GPS) is the first commercial communication system that uses spread spectrum signals enabling ranging, jamming protection, multipath protection and high degree of range precision. In today’s world, there are more applications of spread spectrum on the commercial side than on the military side. CDMA is a popular multiple access scheme where several users share the same physical medium, that is, the same frequency at the same time. CDMA is based on spread spectrum technique where the spectral band is spread by multiplying each user’s signal by unique orthogonal pseudorandom sequence. Orthogonality of the codes ensures the retrieval of information without interference from each other where spreading allows the receiver to take benefit from multipath properties of the mobile radio channel. Over the years, the most successful implementation of spread spectrum communication in commercial world lies in cdma 2000, WCDMA and UMTS, a 3G mobile communication system, WLAN, Ultra Wideband Communications (UWB), Body Area Networks, and energy efficient Radio Architecture design for future generation Millimeter Wave (mmWave) communications. The common cordless phone utilizes spread spectrum technology to provide a telephonic interference-rejecting communication link in both 900 MHz and 2.4 GHz bands. In addition, spread spectrum communication methods have been considered an alternative to hard wiring for indoor private branch offices, laboratories, or factories where the transmission medium involves severe multipath fading.

The present course introduces basic principle of spread spectrum techniques, key concept of code designing supported by Galois field mathematics, understanding Jamming environment and interference handling mechanisms. The theoretical principles are tempered with their practical significance to cope up with the interest to both researchers and system designers. Learning is facilitated by streamlined derivations, tutorials, and assignments. Several systems examples help students understand the concept and tutorials offer quick practice. After an in–depth exposure to spread spectrum techniques and wireless cellular environment the course takes a thorough tour of training on wireless multiuser system design with spread spectrum technique in MATLAB platform. The course ends with an expose to cdma2000 and WCDMA protocol structure and brief introduction to low probability of intercept methods.

Pre-requisites

Digital Communication

Fundamentals of Wireless Communications

Industries that will recognize this course

Spread Spectrum Communications is the core technology for secured Defence Communication Systems. It is also applied to several modern commercial communication systems e.g. CDMA in 3G, and upcoming Millimeter Wave Communications. Hence all Defence R&D labs under Ministry of Defence will be in need of the course.

Course instructor

Debarati Sen is presently an Assistant Professor at the G.S.S. School of Telecommunications, IIT Kharagpur since 2013. She, a National Doctoral Fellow, completed her PhD in Telecommunication Engineering from IIT, Kharagpur in 2010. During 2011-2012, she was a Postdoctoral Researcher with the Department of Signals and Systems, Chalmers University of Technology, Sweden. She was with Samsung Research, Bangalore, India, firstly as a Chief Engineer during 2009-2011 and then as a Senior Chief Engineer during 2012-2013. A university topper in her Master in Engineering, she possesses experience at different levels in different institutions/industries throughout her career.

Her primary research interests are in the broad areas of Wireless Communications and Optical Communications, mostly, on 5G Communications, Millimeter Wave (mmWave) Communications, Large MIMO Systems, Cloud RAN, Short Range Communications, Green Communications, and Coherent Fiber Optical Communications. More specifically, in mmWave Communications, the focus is on energy efficient Radio Architecture and MAC protocol design, devising Beam-forming Algorithm, Performance and Coverage Analysis of Networks. In Large MIMO, she focuses on Synchronization and Channel Estimation, Joint Decoder Design, Cross Layer Optimization, Resource control issues in massive MIMO. Dr. Sen’s research projects are supported by a variety of Govt. organizations including MHRD, BEL, DeitY, and external collaborators like AIRBUS, Samsung, DAAD (Germany) etc. She has several granted and applied Patents to her credit and published extensively in International Journals and Conferences of repute.

She is an editorial board member of two International Journals. Her professional involvement also includes: Member, Mentor Council for NCVT, Govt. of India; Chairing Technical Sessions and TPC membership of top tier IEEE Conferences; Reviewer of IEEE Journals and Conference papers; Delivering invited lectures in academia/industry. She received Best Paper Award at Samsung Tech. Conference 2010, IEI Young Engineers Award 2010, Award of Excellence by Samsung Research, Bangalore in 2010, IETE N.V.G. Memorial Award 2013, DAAD-IIT Faculty Exchange Fellowship 2014 etc. She is a member of IEEE.

Course layout

Week 1: Types of Spread Spectrum Systems: Different Spreading Techniques will be addressed

Week 2: Spreading Sequences: Generation Mechanism of sequences and Waveforms
Week 3: Properties of Spreading Sequences: Code Properties and comparative studies

Week 4: Systems under Jamming: Performance Analysis
Week 5: Galois Field Mathematics:
Concept of code generator polynomial and characteristic     equation
Week 6:
Interference Rejection Techniques
Week 7:
Code Acquisition Mechanism
Week 8:
Code Tracking Mechanism
Week 9:
Concept of Fading Channels and Diversity
Week 10:
CDMA Technology and Interference Handling Mechanisms
Week 11:
MUD and Performance Analysis of CDMA Networks
Week 12:
WCDMA; Low Probability of Intercept Methods


Certification exam:

• The exam is optional for a fee. Exams will be on 23 April, 2017

• Time: Shift 1: 9am-12 noon; Shift 2: 2pm-5pm

• Any one shift can be chosen to write the exam for a course.

• Registration url: Announcements will be made when the registration form is open for registrations.

• The online registration form has to be filled and the certification exam fee needs to be paid. More details will be made available when the exam registration form is published.

Certificates:

• Final score will be calculated as : 25% assignment score + 75% final exam score.

• 25% assignment score is calculated as 25% of average of 12 weeks course: Best 8 out of 12 assignments.

• E-Certificate will be given to those who register and write the exam and score greater than or equal to 40% final score. Certificate will have your name, photograph and the score in the final exam with the breakup. It will have the logos of NPTEL and IIT KHARAGPUR. It will be e-verifiable at nptel.ac.in/noc.