umts radio planning approach

ICM N OP MS ND 8 N.L. Shrestha 1

UMTS Radio Network Planning Approaches Part 2

Narayan Lal ShresthaCoC, Bangkok

[email protected]


UMTS Radio Planning Approaches• Contents:

– Path loss Model– Impact of TMA

• For a given set of parameters and area to be provided coverage, the difference in the site count with and without TMA.

– Cell load for radio network planning.• The impact of maximum cell load selection in UMTS radio

network planning.


The Path Loss Model• The COST-231 path loss model can be written as:

Lpathloss= Const. + s1 log(d)

Where d is the distance in km. The const. depends only on the base station antenna height for a given clutter type, mobile antenna height and carrier frequency.

• s1 depends only on the base station antenna height.

m

hlog55.69.44s BS1


Site Count and Path Loss• If L1 and L2 are the path losses corresponding to the

distances d1 and d2, then the following equation holds when other parameters remain the same and hence s1 also is the same for the two cases:

, where, L2 - L1= L

1sL

12 10dd


Site Count and Path Loss• The following equation shows the relationship between

the site counts and difference in allowed path losses.

Where L = L2 - L1 and S2 and S1 are the site counts for coverage at allowed path losses L2 and L1 respectively.

1s

L22

12

21 10

dd

SS


Site Count for different Bearers• The link budget equation can be written as:

• Difference in the maximum allowed path loss

• When considering the same clutter type and same cell load

BodynPenetratiob

ULMax LL)1log(10NoE)Rlog(10KL

2B1B2ob1ob2

121 LLNENE

RRlog10LL

2B1B2p1p212ob1ob2

121 LLLLNRNRNENE

RRlog10LL


• Eb/No values for UL in different services. Service R UL

Voice 12.2 6.1Streaming64 64 3.8Streaming128 128 2.9Inter/Back64 64 3.6Inter/Back128 128 2.9Inter/Back384 384 2.3


• Considering voice as the reference we get the following result.

Service UL

Voice 12.2 6.1Streaming64 64 3.8Streaming128 128 2.9Inter/Back64 64 3.6Inter/Back128 128 2.9Inter/Back384 384 2.3


Site Count and Path Loss• The effect of reduction in allowed path loss on

site count for coverage.The Impact of Allowed Pathloss on Site Count

100%110%120%130%140%150%160%170%180%190%200%

0 1 2 3 4 5

Decrement in Allowed Path Loss (dB)

The

Incr

ease

in S

ite C

ount

Antenna Height 35 mAntenna Height 15 m


Impact of TMA• The gain TMA introduces in link budget is 5 dB

assuming 3 dB gain by compensating feeder cable loss and 2 dB by improvement in noise figure. i.e. the allowed path loss will increase by 5 dB.

• Hence without TMA the number of sites needed for coverage will increase by 86% to 94% (for Node B antenna heights 35 m and 15 m) compared to those with TMA.


Impact of TMA• If TMA only compensates the cable loss, i.e.

L = 3 dB, then the site count without TMA is 149% to 145% (depending antenna height is 35 m or 15 m) compared to those with TMA.


Cell Load• UL cell load decreases the allowed path loss by

the amount of the noise rise it generates.

• With lower cell load threshold the site count for coverage can be reduced.

• The capacity of the network decreases at a faster rate due to decreased cell load and site count.


Cell Load• The ratio of the required number of sites can be

calculated based on the following equation.

Where S1 and S2 are the number of sites required at cell loads 1 and 2 respectively.

1s20

21

12

11

SS


Cell Load and Site CountNumber of Sites Required At Different Cell Loads

Compared To That With Cell Load 30% (Node B Antenna Height 35 m)

100

110

120

130

140

150

160

170

180

190

30% 40% 50% 60% 70% 80%

Cell Load

%


Cell Load• The number of sites needed for coverage at cell load

70% is 63% more than that at cell load 30% at Node B antenna height of 35 m.

• Hence the network capacity would increase by 3.80 (=1.63 X 70/30) times. This, in the fully utilized scenario, is also the ratio of the maximum traffic densities supported for a given carrier configuration.

• The figure in the next slide shows that at 30% cell load, the site count is reduced by about 15% compared to that at 50% cell load. But the network capacity decreases by 50%.


Cell LoadNumber of Sites Required At Different Cell Loads

Compared To That With Cell Load 50% (Node B Antenna Height 35 m)

80

90

100

110

120

130

140

150

160

30% 40% 50% 60% 70% 80%

Cell Load

%


Cell Load and Network Capacity• The capacity of the network changes as the cell load

changes.

1s20

2

1

1

2

1

211

SS


Cell Load and Network CapacitySite Count and Network Capacity vs Cell Load

Relative To Cell Load 50% (Node B Antenna Height 35 m)

50

70

90

110

130

150

170

190

210

230

30% 40% 50% 60% 70% 80%

Cell Load

%

Site Count Network Capacity


Cell Load and Coverage• The network planned at cell load 30% (left) leaves behind a web

of area without coverage when the load is increased beyond this value (right).


Cell Load• The new site layout will look like the following figure.


Cell Load• To provide continuous coverage to the area, new

sites must be interleaved with the old ones as there is no way to increase power of the mobile.

• The number of sites increases by a factor of 4 compared to just 1.63 in case of radio network planning at cell load 70%.


Cell Load• The following equation shows that halving the

cell range gives about 10.47 dB to 11.20 dB increase in the allowed path loss depending on the Node B antenna height 35 m or 15 m.

1

21 d

dlogsL


Cell Load• At 30% cell load the noise rise is 1.5 dB. With an increase of

allowed path loss of 10 dB, theoretically cell load of 93% (with noise rise 11.5 dB) can be supported. The capacity of the network has increased by more than a factor of (4 x 93/30) = 12.4.

Noise Rise Vs Cell Load

0.0

2.0

4.0

6.0

8.0

10.0

12.0

14.0

0% 10% 20% 30% 40% 50% 60% 70% 80% 90% 100%

Cell Load (%)

Noi

se R

ise

(dB

)


Cell Load• However the maximum UL cell load recommended is only 70%.

Hence the usable capacity is only (4 X 70/30) = 9.33 times that of the network designed for cell load 30%.

• This capacity can be fully utilized only if the traffic demand density increases by a factor of 9.33, i.e. the total traffic demand within the area increases by factor of 9.33.

• Here the chances of increased traffic demand is limited by the area that is covered, since sites can not be moved (or not convenient to do so).


Optimized Planning• The long term optimized radio network can be designed

in the following steps:– Clearly, the knowledge of the traffic demand is essential for

optimized UMTS radio network planning.– The first step would be to find the maximum expected traffic

during the expected period of operation. – Then the maximum cell load per carrier, so that the site count

for coverage also matches traffic demand.


Optimized Planning• If the calculated cell load is < 70%

– then design the coverage network with this value of cell load. Start the net Optimized Planning work rollout with the least number of carriers possible. Go on adding more carriers as demand increases.

– When the capacity of the network is fully used up, additional capacity may be obtained with new technologies, e.g. Smart Antenna, Multi User Detection (MUD).

– Here the upgrade cost and expected time of deployment of Smart Antenna and MUD should be compared against the cost of running the network initially designed with cell load 70%.

– Here the availability of the Smart antenna and MUD is also crucial.

© Siemens, Roadmap - UMTS Radio 27

NB TDD Trial

Location Services A-GPS

SMS Cell Broadcast Service based

Intersystem HO Transcoder free Op Call tracing

Platform and TechnologyNew Features and Services

Successive introduction of UMTS – GSM interworking

Soft and softer Handover

384 kbit/ s

High performance RNC-750

NB-530/ NB 531 (FDD macro)

FDD Pilot UMR 1.0 12/ 00

IP based Interfaces IPbRAN Trial SW Radio Common RNC FDD/TDD NB TDD

S.M.A.R.T Multi User Detection Radio Capacity

Enhancements Smart Antennas

Wideband AMR23,85 kbit/s

Seamless Services FDD/TDD

Common Radio Resource Management

High Speed Downlink Packet Access

UMR 4.0 12/ 03

Roadmap – UMTS RadioHighlights for World Market

Cost of Ownership

FDD 3GPP (Rel.99 03/01)

Capability for IOTIu, Iur, Uu

Successive enhancements of FDD Pilot

Multiple Sessions SMS

UMR 1.5 IOT 12/ 01

UMR 3.0 12/ 02

Common Radio Commander2G & 3G

Multi-vendor interfaces Equipment Sharing

Multi-VendorConfig. Management

Adaptive Rate Control RAB Queuing and Pre-

emption

Issue 28.09.01approved in UR IPP-0901MR UR PLM 8, Dr. Bartels

UMTS radio Evolution

UMR 2.0 03/ 02 UMTS – GSM

Handover Support of QoS

classes Location Services

Cell ID

NB 440/441 NB 640G (FDD/GSM)*) NB 540 (3/3/3) *) NB 341 (FDD micro)

*) Available in 09/02

Optimized Planning


Optimized Planning• If the calculated cell load is > 70%

– Network has to be designed for the cell load 70%. If more capacity is needed in the beginning more sites have to be used.

– When the capacity of the network is fully used up, additional capacity may be obtained with new technologies, e.g. Smart Antenna, Multi User Detection.


Thank You.

umts radio planning approach

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