ELEC-E7120 Wireless Systems (5 cr) Presentation of the Group Assignment Group Number 8 Aalto School of Electrical Engineering, Aalto University, Espoo, Finland

Content Introduction Problems Assumptions Measurements Conclusion Solution 2

Introduction Week 38 Signal measurement Netradar and OpenSignal Operators –Saunalahti –Sonera –DNA 3

4 Some data from Netradar

Problems Poor service Low/bad quality of phone calls Dropped phone calls Bad data coverage 5

The chosen location Jämeräntaivel 3 Bad signal quality Operator: Saunalahti Environment –Close to the sea –Surround by forest –Buildings with thick walls 6

Assumptions (1) There is no Base Station near by: 7 Reflection from vegetation, which cause attenuation Source: ITU-R, Vol. V, Rep

Assumptions (2) There is not enough flat surfaces where the signal can be reflected The antenna is not directive in the direction of the building 8 Building

Assumptions (3) The signal from the BS could not achieve the building, since it is located in downhill 9

Measurement Campaign 10

Result and Analysis (1) 11

Result and Analysis (2) 12

Result and Analysis (3) 13

Result and Analysis (4) According to 3GPP TS , which is implemented in Android, the table below summarizes how the ASU and Received power is calculated 14

Result and Analysis (5) The fomula used to calculate power in dBm is –P(dBm) = 10 · log10( 1000 · P(W) / 1W) = 10 · log10( P(W) / 1W) W = 30dBm In Netradar application Signal Strength is calculated in % by using the below formula –Percentages within range = no signal at all, 100 = the best possible signal. –Raw signal strength value (ASU) is converted to a percentage using a conversion formula (ASU / 97.0 * 100) for LTE network and (100.0 / 31.0 * ASU) for GSM networks (2G and 3G). In opensignal, the dBm values are available in the application 15

Result and Analysis (6) The received power inside the building is much lower than other measurements 16

Conclusion The fact of building is in downhill Walls are too thick There is a lot of attenuation from the vegetation No reflection from flat surfaces 17

Solutions (1) Cell Phone Signal Booster: designed to amplify a weak outside signal and provide a strong signal inside. 18

Solutions (1) Repeater: a possible solution should be to put a repeater above Taffa, so the signal could achieve the building 19