umts dimension ing workshop

UMTS Dimensioning Workshop

© Cirta Consulting 2001 1

UMTS Dimensioning Workshop By Dr. Hatem MOKHTARI

Brussels, June 2001



1. Introduction This workshop aims at providing UMTS Network dimensioning practical guidelines. The self-test proposed herein helps understanding the required RF and System Parameters in view of an accurate linkbudget and cell count computation along with capacity planning issues. The following steps will be treated :

a. UMTS Link Budget b. Demand Modelling c. Capacity Calculation d. Mixed Service Aspects

2. Reminder

2.1. Maximum Allowed Path Loss

2.1.1 Uplink MAPL(UL) = EIRP(MS) – S(BS) – LOSSES(BS) + AntennaGain(BS) + Margin(UL)

2.1.2 Downlink MAPL(DL) = EIRP(BS) – S(MS) – LOSSES(MS) + AntennaGain(MS) + Margin(DL)

2.1.3. The Engineering Margin (Noise Rise)

The loading factor correction is given by the following analytic equation: LoadingFactorCorrection = - 10log(1-CellLoad)

2.2. Sensitivity

Factory Values : Base Station Mobile Station Thermal Noise Density -174 dBm/Hz -174 dBm/Hz Receiver NF (Pedestrian) 3 dB 8 dB

Base Station : S(BS) = ThermalNoiseDensity + ReceiverNF(BS) + 10log(Bit Rate) + (Eb/No)(BS)

Mobile Station : S(MS) = ThermalNoiseDensity + ReceiverNF(MS) + 10log(Bit Rate) + (Eb/No)(MS) LCD384 UDD64 (Eb/No)(BS) 1.3 1.5 (Eb/No)(MS) 1.1 1.2 Given the above data, fill in the grey-shaded blanks in the following tables. Since the BS Output Power is unknown you need to balance the link budget to find it.



FOR LCD384 Coverage Service : Deep

Indoor Bearer Service : LCD384 Morphology : Urban Cell Load : 50%

Mobility : Pedestrian

Downlink Uplink Station(TX) Station(RX)

Units Value Value Units Power W

dBm dBm 17.9 dBi Antenna Gain dB 3 dBi Losses

dBm Sensitivity EIRP dBm

Mobile (RX) Mobile (TX) 0.13 W Power dBm

Antenna Gain dBi 2 dBi Antenna Gain Losses dB 0 dB Losses

Sensitivity dBm dBm EIRP

Margins Margins Soft/Hard HO Gain dB 5 dB Soft/Hard HO Gain Non Orthogonality dB -2

Margin

Interference Margin dB -3 dB Interference Margin Shadowing Margin dB -9.7 dB Shadowing Margin

Body Losses dB 0 dB Body Losses Penetration Margin dB -21 dB Penetration Margin

PC Inperfection dB -2 dB PC Inperfection

MAPL dB dB MAPL FOR UDD64



Coverage Service : Deep Indoor Bearer Service : UDD64

Morphology : Urban Cell Load : 50%



Units Value Value Units Power W

dBm dBm 17.9 dBi Antenna Gain dB 3 dBi Losses

dBm Sensitivity EIRP dBm

Mobile (RX) Mobile (TX) 0.13 W Power dBm

Antenna Gain dBi 2 dBi Antenna Gain Losses dB 0 dB Losses

Sensitivity dBm dBm EIRP

Margins Margins Soft/Hard HO Gain dB 0 dB Soft/Hard HO Gain Non Orthogonality dB -2

Margin

Interference Margin dB -3 dB Interference Margin Shadowing Margin dB -9.7 dB Shadowing Margin

Body Losses dB 0 dB Body Losses Penetration Margin dB -21 dB Penetration Margin

PC Inperfection dB -2 dB PC Inperfection

MAPL dB dB MAPL 2.2. Radius Calculation The following Propagation Model is assumed to be suitable for dense urban area: Lp = K1 + K2 log(R) with K1 = 139.8, K2 = 34.78 Calculate the UMTS Cell radius for both LCD384 and UDD64. The cell load is assumed to be 50% ! How many Tri-Sector Cells are necessary to fulfil the following coverage service : LCD384 Deep Indoor for a 50 km2 urban service area UDD64 Deep Indoor for a 50 km2 urban service area 2.3. The Base Station Power The Base Station Power is 20W. 20% of this power is used by the pilot channel. How many subscribers using LCD384 can simultaneously be serviced. We assume that they are all in a deep indoor environment and located at the cell border.The loading is 50%.



Do the same calculation for the UDD64 case 2.4. NLOAD and Cell Load

Where the Uplink Pole capacity is given by :

Where dBI

I

c

o 5.2−=

Gs = 1.0 for omnidirectional cells and 2.55 for tri-sectorial cells CAF : The Channel Activity Factor (typically 80% for TCH) How Many users could handle the base station. The required cell load is 50%. We assume the following cases :

i) LCD384 and UDD64 number of users are the same ii) Only UDD64 users are involved

Compare the two results i) and ii) for UDD64 Capacity

ANSWERS

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FOR LCD384 First compute the Base Station Sensitivity : S(BS) = ThermalNoiseDensity + ReceiverNF(BS) + 10log(Bit Rate) + (Eb/No)(BS) S(BS) = -174 + 3 + 10log(384000) + 1.3 = -113.8 dBm Second compute the Mobile Station EIRP : EIRP(MS) = Pout(MS) + AntGain5MS) EIRP(MS) = 21 + 2 = 23 dBm Finally Compute the MAPL(UL) : MAPL(UL) = EIRP(MS) – S(BS) – LOSSES(BS) + AntennaGain(BS) + Margin(UL) MAPL(UL) = 23 +113.8 – 3 + 17.9 + 5 – 3 - 9.7 – 21 – 2 = 121 dB This should be the same for the Downlink to get the link balanced : MAPL(DL) = 121 dB The MS Sensitivity is the computed : S(MS) = ThermalNoiseDensity + ReceiverNF(MS) + 10log(Bit Rate) + (Eb/No)(MS) S(MS) = -174 + 8 +10log(384000) + 1.1 = -109 dBm The BTS EIRP is thus deduced from : MAPL(DL) = EIRP(BS) – S(MS) – LOSSES(MS) + AntennaGain(MS) + Margin(DL) Or EIRP(BS) = MAPL(DL) + S(MS) + LOSSES(MS) - AntennaGain(MS) - Margin(DL) Margin(DL) = +5 SHO Gain - 3 Load Factor @ 50% -9.7 Shadowing Margin - 0 Body Losses - 21 Penetration Margin - 2 Power Control Imperfection = -30.7 dB EIRP(BS) = 121 – 109 + 0 + 30.7 = 42.7 dBm Thus the BTS Output Power is Given by : Pout(BS) = EIRP(BS) – AntGain(BS) + Cable Losses Pout(BS) = 42.7 – 17.9 + 3 = 27.8 dBm = 0.6 W Important Note : 0.6 W is per link ! If 50 users have to be serviced simultaneously the power should be 50X0.6 = 30 Watts !

SUMMARY FOR LCD384 CASE STUDY



FOR LCD384 Coverage Service : Deep

Indoor Bearer Service : LCD384 Morphology : Urban Cell Load : 50%



Units Value Value Units Power W 0.6

dBm 17.8 dBm 17.9 17.9 dBi Antenna Gain dB 3 3 dBi Losses

-113.8 dBm Sensitivity EIRP dBm 42.7

Mobile (RX) Mobile (TX) 0.13 W Power 21 dBm

Antenna Gain dBi 2 2 dBi Antenna Gain Losses dB 0 0 dB Losses

Sensitivity dBm -109 23 dBm EIRP

Margins Margins Soft/Hard HO Gain dB 5 5 dB Soft/Hard HO Gain Non Orthogonality dB -2

Margin

Interference Margin dB -3 -3 dB Interference Margin Shadowing Margin dB -9.7 -9.7 dB Shadowing Margin

Body Losses dB 0 0 dB Body Losses Penetration Margin dB -21 -21 dB Penetration Margin

PC Inperfection dB -2 -2 dB PC Inperfection

MAPL dB 121 121 dB MAPL

ANSWERS



FOR UDD64 First compute the Base Station Sensitivity : S(BS) = ThermalNoiseDensity + ReceiverNF(BS) + 10log(Bit Rate) + (Eb/No)(BS) S(BS) = -174 + 3 + 10log(64000) + 1.5 = -121.4 dBm Second compute the Mobile Station EIRP : EIRP(MS) = Pout(MS) + AntGain(MS) EIRP(MS) = 21 + 2 = 23 dBm Finally Compute the MAPL(UL) : MAPL(UL) = EIRP(MS) – S(BS) – LOSSES(BS) + AntennaGain(BS) + Margin(UL) MAPL(UL) = 23 +121.4 – 3 + 17.9 + 0 – 3 - 9.7 – 0 - 21 – 2 = 123.6 dB This should be the same for the Downlink to get the link balanced : MAPL(DL) = 123.6 dB The MS Sensitivity is the computed : S(MS) = ThermalNoiseDensity + ReceiverNF(MS) + 10log(Bit Rate) + (Eb/No)(MS) S(MS) = -174 + 8 +10log(64000) + 1.2 = -116.8 dBm The BTS EIRP is thus deduced from : MAPL(DL) = EIRP(BS) – S(MS) – LOSSES(MS) + AntennaGain(MS) + Margin(DL) Or EIRP(BS) = MAPL(DL) + S(MS) + LOSSES(MS) - AntennaGain(MS) - Margin(DL) Margin(DL) = 0 SHO Gain - 3 Load Factor @ 50% -9.7 Shadowing Margin - 0 Body Losses - 21 Penetration Margin - 2 Power Control Imperfection = -35.7 dB EIRP(BS) = 123.6 – 116.8 – 0 + 35.7 = 42.5 dBm Thus the BTS Output Power is Given by : Pout(BS) = EIRP(BS) – AntGain(BS) + Cable Losses Pout(BS) = 42.5 – 17.9 + 3 = 27.6 dBm = 0.575 W Important Note : 0.575 W is per link ! If 50 users have to be serviced simultaneously the power should be 50X0.575 = 28.75 Watts !



SUMMARY FOR UDD64 CASE STUDY

FOR UDD64 Coverage Service : Deep

Indoor Bearer Service : UDD64 Morphology : Urban Cell Load : 50%



Units Value Value Units Power W 0.575

dBm 27.6 dBm 17.9 17.9 dBi Antenna Gain dB 3 3 dBi Losses

-121.4 dBm Sensitivity EIRP dBm 42.5

Mobile (RX) Mobile (TX) 0.13 W Power 21 dBm

Antenna Gain dBi 2 2 dBi Antenna Gain Losses dB 0 0 dB Losses

Sensitivity dBm -116.8 23 dBm EIRP

Margins Margins Soft/Hard HO Gain dB 0 0 dB Soft/Hard HO Gain Non Orthogonality dB -2

Margin

Interference Margin dB -3 -3 dB Interference Margin Shadowing Margin dB -9.7 -9.7 dB Shadowing Margin

Body Losses dB 0 0 dB Body Losses Penetration Margin dB -21 -21 dB Penetration Margin

PC Inperfection dB -2 -2 dB PC Inperfection

MAPL dB 123.6 123.6 dB MAPL

ANSWERS



NUMBER OF REQUIRED CELLS

Lp = K1 + K2 log(R) with K1 = 139.8, K2 = 34.78

The cell surface can easily be computed as : 2.38

9rs =

To find the cell radius, one may use the path loss equation and the MAPL:

i) For LCD384 : 121 = 139.8 + 34.78log(r) which yields r = 0.288 km the unit-surface for a cell is thus s = 0.161 km2 The Number of tri-sector cells is thus : N(LCD384) = 50/0.161 = 309 Cells ii) For UDD64

123.6 = 139.8 + 34.78log(r) which yields r = 0.342 km the unit-surface for a cell is thus s = 0.228 km2 The Number of tri-sector cells is thus : N(UDD64) = 50/0.228 = 219 Cells

ANSWERS

r



BASE STATION POWER If 20% of this power is used by the pilot channel for signal purposes, the remaining power is for Traffic (Voice and Data): 20% of 20 W represents 4W for signalling, the remaining 16 Watts are distributed amongst the maximum number of users. Therefore, the number of users would be :

i) For LCD384 : 16/0.6 = 26 Users using LCD384 Data Service ii) For UDD64 : 16/0.575 = 27 Users using UDD64 Data Service

ANSWERS



UPLINK MIXED-TRAFFIC CAPACITY CALCULATION First we need to know the pole capacities for each service separately :

Applying the above mentioned pole capacity formula we find : M1,max = M(LCD384)max = 6.4 Users M2,max = M(UDD64)max = 27 Users

If we make the assumption the combined loading would not exceed 50% then the following equation applies :

274.65.0 21 MM

+= and

i) If we assume that both services should have the same user number : M1 = M2 = M leads to M = 2.58 Users for both LCD384 and UDD64 users

ii) If only UDD64 is to be considered then : 0.5 = M/27 which leads to a number of UDD64 Users of 13.5

umts dimension ing workshop

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