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TLT-6106 Basic Course on Wireless Communications Exam 4.2.2013 / T. Isotalo

You can use Faculty's calculator or your own caloulator. You can answer in English or Finnish. A list of eguations is
attached to the exam paper.

 

Use clear handwriting and show all the calculations. Boltzmann's constant: 1.380658* 10 P J/K

1.

Convert (1 point)

a) 14 watts to dBm

b) 4 dBm to milliwatts

Explain briefly the following terms related to wireless communications: (5 points)
c) Shadowing

d) Free-space loss

e) Freguency reuse

£) Spreading factor

g) Multipath propagation

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

i) Below you have link budget for GSM1800 system (carrier freguency 1.8 GHz, system bandwidth 200 kHz)
Calculate and fill in the missing values, and calculate the maximum isotropic path losses.
ii) Calculate maximum cell range using Okumura-Hata path-loss formula (tunable parameter = 44 and correction
factor = 0).

UPLINK Unit Value DOWNLINK Unit Value

Mobile station Base station

RF power dBm a) RF power dBm )

Cable loss dB » Cable loss dB x

Tx antenna gain dBi 9 Tx antenna gain dBi »

Peak EIRP dBm ) Peak EIRP dBm m)

Base station Mobile station :

Rx antenna gain dBi 9 Rx antenna gain —| dBi D

Cable loss dB 2 Cable loss dB 9

BTS sensitivity dBm 2) MS sensitivity dBm ”

Minimum dBm ” Minimum dBm 9

reception level reception level

Isotropic path loss | dB ) Isotropic path loss | dB )
At the base station end, the transmitter has 20 W maximum power, antenna height and cable length are 33 m, antenna
cable has loss of 6 dB/100 m, and base station antenna has 15 dBi gain. Mobile station maximum power eguals to 1

 

W, cable loss can be approximated to 0 dB, and antenna can be assumed to be isotropic. Base station noise figure is 4
dB and mobile station 8 dB, and signal-to-noise reguirement for both directions is 7 dB.

(9 points)

a) A mobile phone subscriber generates on average 1.2 min voice traffic during the busy hour. How many
subscribers in a cell having 30 traffic channels will cause a blocking probability of 1 % (1 point)
b) How many subscribers can be served at the different blocking levels? (1 point)

€) Compare the trunking efficiency in the following two alternative configurations: (i) 1 group of 10 channels, (ii) 2
groups of 5 channels, both with 1% blocking probability. (1 point)

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TLT-6106 Basic Course on Wireless Communications Exam 4.2.2013 / T. Isotalo

You can use Faculty's calculator or your own calculator. You can answer in English or Finnish. A list of eguations is
attached to the exam paper.

4.
a) Compare briefly (in terms of propagation characteristics) the High Freguency range (3-30 MHz) with Super High
Freguency range (300-3000 MHz). Think about the common and distinct properties in each of these two ranges.

(3 points)
b) Explain what impacts do sectoring, antenna downtilt and antenna height have on cellular network coverage and
capacity. (3 points)

Answer to guestion 5 OR 6. If you answer to both, the one giving LESS points will be taken into consider.

5. Explain the figure below: (6 points)

N

 

E Detailed Planning
Dimensioning / A) - Configuration planning N Post-Planning /
Pre-planning A - Coverage Planning Optimization

/

 

  

6. Explain radio resource management, transmit power control, load control, admission control, and mobility (handover)
control. (6 points)

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