Final Exam 2013

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University of Toronto, ECE1508 Winter 2013 Page 1 of 11 Name: Student ID: UNIVERSITY OF TORONTO DEPARTMENT OF ELECTRICAL & COMPUTER ENGINEERING ECE 1508 Special Topics in Communications: 4G LTE for Mobile Broadband Date: April 9, 2013 Time: 3 pm – 5:30 pm Examiner: Ivo Maljević Instructions: 1) Only a non-programmable calculator and the provided aid sheet are allowed in the exam. 2) Answer all 7 questions. 3) Write the answer to each question starting on the page of the question and on the following blank page if necessary. 4) Answers must be very clear and show justification. Question 1 2 3 4 5 6 7 Marks

University of Toronto, ECE1508 Winter 2013 Page 2 of 11 1) (6 points ) Answer the following questions: a) Describe the cell search procedure. b) Describe the random access procedure. c) Describe the timing advance procedure. d) Describe channel feedback reporting. e) Describe the difference between TDD and FDD LTE. f) What is a noise figure?

University of Toronto, ECE1508 Winter 2013 Page 3 of 11 2) (7 points ) Two Bell LTE base stations (W2015 and W1864) near the University of Toronto campus are shown in the picture below. If the UE is located at the position indicated by the pin “UE Location” , determine the following: a) Distance between the UE and the two basestations, if the distance between the basestations is 511.6 m and the angles shown in the picture are α = 24.3247 o and β = 11.1068 o . b) Pathloss from each basestation to the UE if the pathloss model is PL( d ) = 128.1 + 37.6 log10 ( d ), where d is in km. c) Geometry (SINR) at the UE location assuming that the thermal noise effect is negligible. Use the pathloss model given in b). d) Using the SINR from c), determine achievable data rates in the DL and UL using α -Shannon approximation. For the UL data rate calculation, assume 4 RBs are used and for the DL assume 10 MHz channel. α β γ

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University of Toronto, ECE1508 Winter 2013 Page 4 of 11

University of Toronto, ECE1508 Winter 2013 Page 5 of 11 3) (8 points ) An LTE UE is attached to an isolated cell and it reports RSRP = -105 dBm and RSRQ = -10 dB. If the system bandwidth is 10 MHz and the effective eNodeB transmit power is EIRP = 60 dBm, determine the following: a) RSSI and pathloss values for the given parameters. b) Determine the power per data subcarrier assuming that RS signals (pilots) use power boosting (data subcarriers and pilots have different power levels). c) If the pathloss model is PL( d ) = 128.1 + 37.6 log10 ( d ), where d is in km, determine the distance of the UE from the eNodeB. d) If the UE noise figure is NF = 9 dB, determine the SNR per individual data subcarrier for the given UE. e) Using the α -Shannon capacity formula for the DL, determine how much data can be carrier by each subcarrier.

University of Toronto, ECE1508 Winter 2013 Page 6 of 11

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University of Toronto, ECE1508 Winter 2013 Page 7 of 11 4) (4 points ) Using the tables below (from TS 36.213) select the proper number of resource blocks for the LTE system with the channel bandwidth of 5 MHz, and then determine the peak downlink data rates for: a) SISO mode transmission b) MIMO mode transmission Also, using the α -Shannon formula, determine the required SINR for the data rate determined in a). Assume that the channel bandwidth is equal to the bandwidth occupied by the resource blocks. Transport block size table (partial table) TBS I PRB N 21 22 23 24 25 26 27 28 29 30 16 6712 7224 7480 7736 7992 8504 8760 9144 9528 9912 17 7480 7992 8248 8760 9144 9528 9912 10296 10296 10680 18 8248 8760 9144 9528 9912 10296 10680 11064 11448 11832 19 9144 9528 9912 10296 10680 11064 11448 12216 12576 12960 20 9912 10296 10680 11064 11448 12216 12576 12960 13536 14112 21 10680 11064 11448 12216 12576 12960 13536 14112 14688 15264 22 11448 11832 12576 12960 13536 14112 14688 15264 15840 16416 23 12216 12576 12960 13536 14112 14688 15264 15840 16416 16992 24 12960 13536 14112 14688 15264 15840 16416 16992 17568 18336 25 13536 14112 14688 15264 15840 16416 16992 17568 18336 19080 26 15264 16416 16992 17568 18336 19080 19848 20616 21384 22152 One-layer to two-layer TBS translation table (partial table) TBS_L1 TBS_L2 TBS_L1 TBS_L2 TBS_L1 TBS_L2 TBS_L1 TBS_L2 2280 4584 5736 11448 15840 31704 43816 87936 2344 4776 5992 11832 16416 32856 45352 90816 2408 4776 6200 12576 16992 34008 46888 93800 2472 4968 6456 12960 17568 35160 48936 97896 2536 5160 6712 13536 18336 36696 51024 101840 2600 5160 6968 14112 19080 37888 52752 105528 2664 5352 7224 14688 19848 39232 55056 110136

University of Toronto, ECE1508 Winter 2013 Page 8 of 11

University of Toronto, ECE1508 Winter 2013 Page 9 of 11 5) (5 points ) Using the tables below, determine the peak DL and UL rates for the SS format 7, DL/UL configuration 5. Assume that the TDD-LTE system in question uses the system bandwidth of: a) 10 MHz b) 20 MHz and the device for which the peak data rates are calculated is a category 3 device. DL/UL Configuration DL:UL Ratio Subframe number 0 1 2 3 4 5 6 7 8 9 5 9:1 D S U D D D D D D D SS Format DwPTS GP UpPTS 7 10 2 2

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University of Toronto, ECE1508 Winter 2013 Page 10 of 11 6) (5 points ) Populate the DL link budget table below with the missing values Downlink LTE 10 MHz LTE 20 MHz Data rate (Mbps) 1 1.5 Transmitter - eNodeB Tx power (dBm) 46 48 Tx antenna gain (dBi) 18 18 Cable loss (dB) 2 2 EIRP Receiver - UE UE noise figure (dB) 9 9 Thermal noise (dBm) Receiver noise floor (dBm) Required SINR (dB, from alpha-Shannon formula) Receiver sensitivity (dBm) Interference margin (dB) 4 4 Rx Antenna gain (dB) 0 0 Shadowing margin (dB) 8.8 8.8 In-building penetration loss (dB) 20 20 Maximum allowable pathloss (dB)

University of Toronto, ECE1508 Winter 2013 Page 11 of 11 7) (5 points ) Answer the following questions: a) What is the purpose of semi-persistent scheduling? b) What is range extension and why is it used? c) What are almost blank subframes used for? d) Determine the receive sensitivity at the UE if 40 resource blocks are used in the DL. The noise figure is 9 dB and the required SINR = - 5 dB. e) What is the preferred MIMO mode (open vs. closed loop) in high mobility scenario? f) Describe ICIC techniques for the DL and UL.