New students are strongly encouraged to take placement exams to determine if they may be exempt from two of the initial technical core courses, ENTS 622: Introduction to Digital Communication Systems and ENTS 640: Networks and Protocols I. If students do not take the placement exams, they will be expected to enroll in both of these courses. If you pass either of the exams, this will allow you to select additional electives as a part of your program of study. You can view the topics that will be addressed on each of these exams below. Sample questions are also provided in an exam format and can be viewed at the links below. The solutions are provided at the bottom of the sample test document.
The placement exams for each of these courses will be administered on the following date. Exams will begin promptly at time indicated below, please arrive early. Late arrivals will not be permitted to take the exam. Students have one chance to take the exam, there are no retakes or other opportunities.
|Date: Thursday, August 17, 2017|
Time (ENTS 640): Sign-In opens at 9:30 AM; Exam begins at 10:00 AM
Time (ENTS 622): Sign-In opens at 10:45 AM; Exam begins at 11:00 AM
|Location: 0130 Tydings Hall|
Students need to bring the following items: University Student ID card or government-issued ID and pencils. Scrap paper will be provided.
The following items are NOT permitted: no calculators, no mobile devices, no notes, no books, no laptops, no open backpacks or bags. There will be no breaks or leaving the room during the exam. No talking or communicating with other students will be permitted during the exam.
Students who arrive late will not be permitted to take the exam.
A. Signals and Systems
- Complex numbers and their operations; continuous-time signals, continuous-time Fourier series, continuous-time Fourier transform; discrete-time signals, discrete-time Fourier transform, discrete Fourier transform; linear time-invariant (LTI) systems, response of LTI systems to discrete- and continuous-time signals, impulse response, convolution, frequency response
B. Probability, Random Variables and Processes
- Relative frequency and probability, discrete/continuous random variables, expected value (mean, variance), multiple random variables, independence, correlation, covariance, law of large numbers, central limit theorem, discrete- and continuous-time random processes, autocorrelation and autocovariance functions, stationarity (strict sense & wide sense), ergodicity, power spectral density, response of LTI systems to random signals, Gaussian noise process
C. Analog Communications
- Amplitude modulation (AM), conventional AM, DSSC-AM, SSB-AM, VSB, frequency division multiplexing, angle modulation, frequency modulation (FM), phase modulation (PM), demodulation techniques, superheterodyne receiver, noise in continuous-wave (CW) modulation systems, performance of AM & FM receivers in the presence of noise, threshold effect, pre-emphasis & de-emphasis in FM, link-budget analysis
D. Digital Communications
- Digital signal modulation/demodulation, sampling theorem, quantization noise, pulse amplitude modulation (PAM), time-division multiplexing, line codes, baseband digital transmission, matched filter, probability of error due to noise, Intersymbol interference (ISI), Nyquist criterion for distortionless transmission, raised cosine spectrum, M-ary pulse amplitude modulation (PAM), digital band-pass techniques, PAM, PSK, FSK, CPFSK, MSK, DPSK, QPSK, QAM modulations, pulse-code modulation (PCM), additional white Gaussian noise (AWGN) channel, optimum receiver, signal-to-noise ratio, probability of bit error
E. Information Theory and Coding
- Entropy, source coding & file compression, Huffman coding, Lempel-Ziv algorithm, channel capacity, binary symmetric channel, channel coding theorem, capacity of a Gaussian channel, error control coding, linear block codes, convolutional codes, coding gain
1. C. Phillips and J. Parr, Signals, Systems and Transforms, 2nd edition, Prentice Hall, 1999.
2. A. Leon-Garcia, Probability and Random Processes for Electrical Engineering, 2nd edition, Addison-Wesley, 1994.
3. S. Haykin, Communication Systems, 4th edition, John Wiley and Sons, 2001.
A. Basic principles
- Circuit switching vs. packet switching; multiuser communication and multiplexing (TDM, FDM, CDMA); TCP/IP layered communication model (5 layers)
B. Link layer
- Error detection and correction: parity, checksum, CRC; random access techniques,channel partitioning (TDMA, FDMA), polling (master/slave), token passing, CSMA/CD; MAC addresses; Ethernet, frame format, ARP: ARP table and operation; switches: switch table, self-learning, switches vs. routers, STP: BPDUs, STP operation, switch port states
C. Network Layer
- Virtual circuit vs. datagram networks; principles of routing; shortest path algorithms: Bellman Ford algorithm, Dijkstra's algorithm; routing implementations: link-state and distance vector algorithms; IPv4: service model, datagram format, IPv4 addresses, subnets, network masks, fragmentation & reassembly; router operation; IPv6: new features, differences from IPv4, datagram format, IPv6 over IPv4 tunneling; NAT and NAPT principles and operation; DHCP: automatic host configuration, DHCP protocol operation
D. Transport Layer
- Ports and sockets; user datagram protocol (UDP): service model, UDP segment format; reliable communication protocols: stop -and-go, Go-back-N and selective repeat; transmission control protocol (TCP): service model, TCP segment format, sequence numbers, acknowledgement numbers, connection setup and teardown, flow control, congestion control
E. Application Layer
- DNS system: DNS name space, zones and zone management, operation of the DNS protocol, DNS message formats and resource records; HTTP protocol: URLs, HTTP message formats, HTTP methods and status codes, cookies, HTTP connection management, parallel, persistent and pipelined connections
1. J. Kurose and K. Ross, Computer Networking: A Top-Down Approach Featuring the Internet, 6th edition, Pearson Education, 2012.
2. A. Leon-Garcia and I. Widjaja, Communication Networks: Fundamental Concepts and Key Architectures, 2nd edition, Mcgraw-Hill, 2003.