Radio Link Budget Tools

5/21/2018 Radio Link Budget Tools

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France Telecom group restricted

Orange Labs

Radio Link Budgets of Orange Labs:

LTE LB V3.6 and HSPA LB V2.0

Orange Labs, RNM/REP/REM


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France Telecom group restricted RNM/REP/REM/ R.NASRI

Synthesis 1/3This presentation answers the following questions:

Objectives of Link Budget Tools

What is the principle of a link budget?

Calculating a cell radius and providing design thresholds to guarantee a target quality of

service

What are Radio Link Budget tool useful for?

Providing a city or country wide rough coverage dimensioning before an investment

committee by providing the maximum cell range.

Providing RSRP/RSRQ or RSCP/(Ec/No) design thresholds as inputs for the ASSET tool in

order to create coverage maps. For comparison studies, the tool is useful to give ideas on system performances and the

sensibility of the outputs to some parameters: power impact, used frequency bands, and

other parameters or radio features.

How many versions? Which complexity?

3 versions available for Orange MCOs: DCH UL, HSPA (UL&DL), LTE (UL&DL)

What were improved with respect to the last versions?

The new version comes with important enhancements such as linear calculations in

DL/UL, restructuring of the tool around two modes (Basic/Advanced) and new modeling

of shadowing and interferences.

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Technical description

What are the differences between the 2 modes of the link budget?

The objective of the basic mode is the maximum cell range knowing the target

Throughput, whereas the advanced mode targets at system performances knowing

inter-site distance.

The basic mode aims at calculating the maximum cell range that ensures a target

throughput, by counting all losses and gains affecting signals between transmitters andreceivers.

For the basic mode, UL and DL link budgets are independently performed. The maintained

planned cell range corresponds to the cell range of the limiting link.

Based on different assumptions related to the structure of the network and to the

propagation model, the advanced mode calculates the interferences from other cells and

thus the throughput are provided for different distances to the serving cell.

The basic mode is suitable for setting design thresholds and planning cell range. Advanced

mode is better when inter-site distance is averagely known and for strategic comparison.

What are the inputs, outputs and main characteristics of the tools?

The main inputs are related to the system, the equipment and the environment

The main outputs are MAPL, UL/DL cell radius, Throughput versus distance andRSRP/RSRQ (or RSCP/Ec_Io for HSPA).

Synthesis 2/3

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Models behind the development of the tool

What are the models and hypothesis taken?

The link budget uses a simple log-distance model including Ukumara hata and cost 231

models.

A new formula of shadowing margin taking into account the multi-cell server probability

is developed and implemented in the tool.

For the Advanced mode, in each unit area of the serving cell, the interference factor F(r)and the SINR (C / I) are computed based on hexagonal Omni grid.

For DL & UL analysis, the Look Up Tables (LUTs) provide a throughput for each

calculated SINR in the cell and vice versa (Throughput => SINR).

Main limits of the models and hypothesis: the Link Budget tools are based on a simple

approach (gains, loss, margins) and formulae.Other information, support

Where to find the tool, other information and which support?

All documentations and these tools are available in a dedicated folder (calledRadio Link

Budget ) of the REM team SharePoint.

For support, contact: [email protected]; [email protected]

Synthesis 3/3

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Objectives of Link Budget Tool

Technical description of the tool


Other information, support

References

Agenda

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What is the principle of a link budget?Calculating a cell radius and providing design thresholds to guarantee a target quality of service

look-up tables

Link Budget

Tool

equipment parameters

environment parameters

Maximum cell range

1

2

3

4

5

8

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6

9

10

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14

13

12

17

16

15

18

0

cell throughput vs distance to

serving cell or RSRP/RSRQ

RSRP/RSRQ & RSCP/Ec/No for

ASSET

0

2040

60

80

100

0,000 0,200 0,400 0,600

Distance (Km)

Throughput versus Distance

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How can the Radio Link Budget tool be useful?LTE/HSPA LB provide a city or country wide rough coverage dimensioning before an investment

committee, give RSCP/RSRP thresholds as inputs for ASSET and highlight system performancesfor different deployment scenarios

1. Before going through an investment committee in order to deploy a new radio access

network: this tool allows to estimate the coverage of a site and then helps operators to

calculate the minimum number of sites to cover a target surface with the user-provided

inputs and parameters and so make a rough coverage dimensioning.

2. Before designing the network with the ASSET: this tool calculates RSRP thresholds and

RSRQ thresholds (for a Downlink and an Uplink Target Throughput), to be used as an

input in the ASSET tool.

3. For a strategic comparison between some deployment scenarios, the tool can give an

idea about the maximum achieved quality of service (in terms of throughput) in different

position from a serving cell and for different parameters values.

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1. Typical cell ranges (Cell Radius):

To be used for a site count on a city or a country

Rough coverage dimensioning for a greenfield deployment before an investment

committee

% of the network covered for a target throughput

New technology rollout for an incumbent operator

What are Radio Link Budget useful for? (1/3)Providing a city or country wide rough coverage dimensioning before an investment committee

Exemple of site dimensioning

LTE DL target throughput = 20 Mbps

LTE 2,6GHz, bandwidth 20Mhz, eNB power 49dBm,Indoor Daylight and coverage probability 95%

The tool gives DL Cell Edge ~0,495Km and an area

of an hexagonal omni-sectorised cell ~ 0,635Km

So,~ 1,5 omni-sectorized cell per Km is required Cell Edge= Maximum radius

Area of a cell=area of one

hexagonal cell

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2. RSCP/RSRP thresholds as input for the ASSET tool in order to create coverage maps:

To be used as an input for the ASSET cell planning tool

Coverage plots computation to ensure a targeted throughput in UL and DL

What are Radio Link Budget useful for? (2/3)Providing RSRP/RSRQ or RSCP/(Ec/No) design thresholds as inputs for the ASSET tool in order

to create coverage maps.

ASSET coverage mapExample: Coverage area for a HSDPA

target throughput.

For HSDPA DL 2 Mbps at cell Edge.

Dense Urban

Indoor Daylight

50% DL load

=> RSCP= -97,1 dBm

=>97% of coverage (ASSET)

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3. The tool allows a strategic comparison between frequency bands

When the inter-site distance is known, LB tool gives a quick comparison between

different technologies or different deployment scenarios

What are Radio Link Budget useful for? (3/3)For comparison studies, the tool is useful to give ideas on system performances and the sensibility

of the outputs to some parameters: power impact, used frequency bands, and other parameters orradio features.

Example: LTE Power impact -

Link budget analysis : Source [1]

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How many LB versions are shared with Orange Affiliates

3 versions available for Orange MCOs: DCH UL, HSPA (UL&DL), LTE (UL&DL).

NameDCH UL

Radio Link Budget

HSPA

Radio Link Budget

LTE

Radio Link Budget

Version V2.5 V2.0 V3.6

Technology UMTS (R99) - UL HSDPA (R10) & HSUPA LTE (R8) - UL & DL

Duplex mode FDD FDD FDD & TDD

Availability Available Available Available

Time delivery ofthe last version January 2013 January 2013

Time of

computationInstantenous Less than 10 sec Less than 10 sec

Project Radio Dimensioning tools

TargetMCOs, OLNC,Orange France

Studies and Internal projectsInterface/encoding Excel, VBA

Documentation User guide + Methodology

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What were improved with respect to the last versions?The new version comes with important enhancements such as linear calculations in DL/UL,

restructuring of the tool around two modes (Basic/Advanced) and modeling of shadowing andinterferences.

1. Restructuring of the link budget according to the operator needs: basic mode deals with the scenario

when the objectives are the maximum cell range and the RSRP/RSRQ design thresholds. Whereas,

advanced mode treats system performances of some network deployment scenarios when the inter-sites distance is known.

2. Withdraw of the balanced and unbalanced modes.

3. For each link, the basic mode gives the planned cell range taking into account the limiting link.

4. Only UL was linear in the last version. In V3.6, the DL is also linear for the basic mode.

5. Modelling of the shadowing margin in multi-cellular environment for both UL and DL.

6. Modelling of DL interferences in basic and advanced mode; i.e. a closed formula of the interference

factor is developed and used.

7. For the advanced mode, both UL and DL are given whereas in V3.5, only DL existed.

8. In addition to RSRP threshold, RSRQ threshold is also given in V3.6 for the basic mode.

9. UL Fractional Power Control (FPC) feature is supported in V3.6 for the advanced mode.

10. New UL louk-up table (SNR vs Throughput) is provided allowing the use of high and different

throughput scenarios.

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Other information, support

References

Agenda

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2 Modes in the LB: What are the differences between them?The objective of the basic mode is the maximum cell range knowing the target Throughput,

whereas the advanced mode targets at system performances knowing inter-site distance.

UL Link Budget

eNode B Tx Power,

local & neighboring cell load

UL Output

UL Throughput as a

function of distance & UL

Throughput versus DL

RSRP/RSRQ

DL Link Budget

Advanced Mode

Uplink & Downlink

Inputs

Coverage & Equipment considerations:

Cell area coverage probability Penetration loss LTE frequency LTE bandwidth Morphology type Propagation parameters

UE Tx Power,

local & neighboring cell load

Inter-site distanceInter-site distance

DL Output

DL Throughput as a function

of distance & DL Throughput

versus DL RSRP/RSRQ

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5

10

15

20

25

30

35

0,1 0,2 0,3 0,4 0 ,5 0 ,6 0, 7

Throughput(Mbps)

Distance (Km)

CellThroughputversusDistance

UL ThroughputMbps

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5

10

15

20

25

30

35

-120 -110 -100 -90 -80 -70 -60

Throughput(Mbps)

RSRP(dBm)

CellThroughput versusRSRP

ULThroughputMbps

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20

40

60

80

100

120

140

160

0, 1 0, 2 0 ,3 0, 4 0, 5 0 ,6 0, 7Throughput(Mbps)

Distance (Km)

CellThroughputversusDistance

DL Throughput Mbps

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20

40

60

80

100

120

140

160

-19,5 -18,5 -17,5 -16,5 -15,5 -14,5 -13,5 -12,5Throughput

(Mbps)

RSRQ (dB)

Cell Throughput versus RSRQ

DLThroughputMbps

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20

40

60

80

100

120

140

160

- 12 0 - 11 0 - 10 0 - 90 - 80 - 70

Throughput(Mbps)

RSRP(dBm)

Cell ThroughputversusRSRP

DLThroughput Mbps

Basic mode requires the target

throughput to get the maximum cell

range (inter-site distance), RSRP,

RSRQ thresholds.

Advanced mode requires the inter-site distance to get the throughput vs

distance to the serving cell.

For basic Mode, the throughput is

known only at cell edge, whereas for

advanced mode, the throughput is

known for every distance to the

serving cell.

At cell edge

The performances of the basic modeare equal to those of advanced mode

only if the value of RoT (Rise over

Thermal) for the basic mode is taken

at the cell edge.

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Basic Link Budget mode principles (1/2)The basic mode aims at calculating the maximum cell range that ensures a target throughput,

by counting all losses and gains affecting signals between transmitters and receivers.

Counting all losses and gains affecting radio signals between

transmitter and receiver = Basic Link Budget calculation

Fast Fading

penetration loss

Body loss

Fixed RoT margin

AAAA

Feeder loss

Antenna

gain

UL MHA

Gain

eNBeNBeNBeNB powerpowerpowerpower

EIRP

Target DL

throughput

Target DL

SINR

DLLin

kcurve

mapping

Target UL

throughput

Target UL

SINR

Shadowing

margin

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Basic Link Budget mode principles (2/2)UL and DL basic link budgets are independently performed. The planned cell range

corresponds the cell range of the limiting link.

&

Calculate UL/DL MAPL

Calculate UL Cell

radiusCalculate DL Cell

radiusSelect the

smaller radius

Calculate Cell area

coverage

Calculate Design

thresholds

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Results (Outputs)

Inter-site distance and

user category

SINR calculation

Interference modelingaccording to load assumption

and network structure

Throughput evaluation

according to distance

Look-up tables

Mapping

Cell throughputVersus

- Distance to theserving cell,

- RSRP/ RSRQ

Input data: Systemparameters, frequency

band,

From

RNM/WTE/RIDE

Advanced Link Budget mode principlesBased on different assumptions related to the structure of the network and to the propagation

model, the interferences from other cells are calculated and the throughput are provided fordifferent distances to the serving cell.

SINR

Throughput

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3

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16

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18

r

i R1

R

1r

0

20

40

60

80

100

120

140

160

0,1 0,2 0,3 0,4 0,5 0,6 0,7Throughput(Mbps)

Distance (Km)

Cell Throughput versus Distance

DLThroughputMbps

0

20

40

60

80

100

120

140

160

-19,5 -18,5 -17,5 -16,5 -15,5 -14,5 -13,5 -12,5Th

roughput(Mbps)

RSRQ (dB)

Cell Throughput versus RSRQ

DLThroughput Mbps

0

20

40

60

80

100

120

140

160

-120 -110 -100 -90 -80 -70

Throughput(Mbps)

RSRP (dBm)

Cell Throughput versus RSRP

DL Throughput Mbps

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What are the suitable use cases of each mode?The basic mode is suitable for setting design thresholds and planning cell range. Advanced

mode is better when inter-site distance is averagely known.

Scenarios Basic Mode Advanced Mode

To dimension the

number of sites

It is suitable for this scenario, since it

gives the coverage of the cell as

output.

It can not be used unless you change many times

the intersite distance until that the target throughput

is achieved at cell edge.

To set designthresholds

(RSRP/RSRQ)

suitable because the target throughput

is achieved at cell edgeSame arguments as above

To study the

performances of

the system when

inter-site distance

is known

It is not suitable because the

interference is taken as a fixed margin

and the tool gives only the minimum

achieved throughput at cell edge

It is better to use this mode because the

interference is better calculated at each point.

However because of the assumption related to the

network regularity, the interference at cell edge is

over-estimated.

Remarque

The coverage given by the basic mode is close to a shifted coverage on field when the RoT

(Rise over Thermal) is a fixed margin.

For a fixed and bounded RoT margin, the basic mode under-estimates the interference at celledge.

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For the advanced mode, the interferences

calculated at cell edge (hatched surface) is

over-estimated because:

- In the majority of points the signals coming

from the first and second interferers are higher

than the signal of the serving cell (in reality this

cannot be happen).

Performances obtained by the advanced-mode

are under-estimated at cell edge.

Performances of advanced mode depend

strongly on link level curve, propagationmodel and network structure.

For the basic mode, the used RoT (Rise

over Thermal) is

The interference factor is taken as the average

over the cell.

The average RoT is always lower than the

RoT calculated at cell edge.

Performances obtained by the basic mode

are quite over-estimated with respect to

terrain situation.

When the link curve (SNR vs

Throughput) is calibrated according tothe labs measures, results of the basic

mode are similar to labs results,

How does each mode deal with interferences?The basic mode under-estimates the interferences at cell edge and the advanced

mode over-estimates it.

=

0/..11010 NSfLog RX

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What are the common inputs of the 2 modes?Main inputs are related to the system, the equipment and the environment

Input Parameter Description Possible values

System

Frequency bandThe operating frequency band

for system.

R99, HSPA: 900, 1800, 2100 MHz

LTE: 800, 1800 , 2600 MHz

BandwidthThe operating channel

bandwidth.For LTE: 5, 10, 15 & 20MHz.

Environnent

Propagation

model

The used propagation model

for the cell range computation

Okumura Hata for 800 & 900MHz frequency band s

Cost231 Hata for higher bands (1800 MHz, 2.1GHz

and 2.6 GHz).

Morphology The environment morphology. Dense Urban, Urban, Suburban & Rural

Penetration type

The indoor configuration that

determines the penetration

margin.

Different types of penetration: indoor window to deep

indoor

Equipment (e)Node B / UE

characteristics

(e)NB and UE characteristics

in terms of maximum output

power, noise figure, etc.

Default values are based on vendors' inputs.

Link-Level

Performance

Look Up Tables

(LUTs)

Tables of Throughput vs SNR

based on internal simulators

From HSPA Fast Simulator : Cat 6 to 14 , PA3

LMMSE Type, w/wo RxDiv

From LTE Fast Simulator: Cat 2 to 5, ePA3, 2x2

MIMO Close loop in DL, Cat 3: 1x2 SIMO in UL

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What are the outputs of each mode?The main outputs are UL/ DL cell radius, RSRP/RSCP Thresholds (for UL/DL)

according to target throughput and throughput versus distance (for the advancedmode) .

Output Mode Description

Maximum UL/ DL Cell radius Basic

UL or DL maximum cell radius for a given UL or DL target

throughput. The corresponding Maximum allowablepathloss (MAPL) is also provided,

Design Thresholds: RSRP/RSRQ

for LTE and RSCP/Ec/No for

HSPA

BasicDesign thresholds to be used in planning tools are

provided for target UL & DL throughputs

UL/ DL Throughput vs distance to

the serving cell or vs RSRP/

RSRQ

Advanced

The advanced mode suitable for strategic comparisonprovides the evolution of throughput as a function of

distance or as a function of RSRP/ RSRQ :

0

20

40

60

80

100

0,000 0,200 0,400 0,600

Distance (Km)

Throughput versus Distance

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Models behind the development of the tool Other information, support

References

Agenda

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Propagation modelsThe link budget uses a simple log-distance model including Ukumara hata and

cost 231 models.

K1 and K2 depend on propagation environment, antenna heights, and carrier

frequency.

Two Propagation Models are used depending on K1 and K2:

Okumura-Hata Model (for f>1,5GHz),

Cost 231 Hata Model (f


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Shadowing modelA new formula of shadowing margin taking into account the multi-cell server

probability is developed and implemented in the tool.

New shadowing margin formula is

developed taking into account the multi-cell

context.

Jakes formulae is very pessimistic and it is

not recommended to be used.

,

,

,

,

,

,

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Step 1: calculation of geometric factor F:

Closed formula is used

Step 2: SINR calculation:

Step 3: Mapping between SINR and Throughput

via Look Up Table (LUT)

0

1

2

3

4

5

8

7

6

9

10

11

14

13

12

17

16

15

18

r

i R1

R

1r

Network structure & InterferencesFor the Advanced mode, in each unit area of the serving cell, the interference

factor F(r) and the SINR (C / I) are computed based on hexagonal Omni grid

seThermalNoirPL

PrFrIr

rC

rSINR NodeBIntra

HSDPA++

=

)()()()(

)(

)(

0

iC

ii

k

PL

PLF =

0

DL

Subcarrier

LTE

PPLNrFrSINR

/)(

1)(

00

_

+=

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LUTs provide throughput vs

SINR curves according to:

channel model

UE category

UE receiver

multiple antenna use

Link Level curvesFor DL & UL analysis, the Look Up Tables (LUTs) provide a throughput for each

calculated SINR in the cell

Cat10 PA3 LMMSE RxDiv

SINR (dB)

HSDPA

Throughput

(kbps)-15 2

-13 11

-11 23

-9 36

-7 52

-5 81

-3 134

-1 2261 360

3 548

5 805

7 1132

9 1522

11 1986

13 2604

15 3674

17 5257

19 7183

21 9081

23 10656

25 11686

27 12291

29 12555

0

2000

4000

6000

8000

10000

12000

0,000 0,500 1,000 1,500

Throughpu

t(Kbits/s)

Distance (Km)

Applicative Throughput versusDistance

2

3

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Other parametersMain limits of the models and hypothesis: Link Budget tools are based on a

simple approach: Values of gains, losses and margins are fixed

Simple approach

Gains (Antenna, MHA) Losses (Body Loss, Penetration Loss)

Margins (Shadowing, UL interference)

Simple formulae

Load (uniform distribution)

Inter-cell interference

SINR

Network design

Does not utilize database of realistic sites (but ASSET does)

Omni site (tri secto is more complex) UL analysis (UL DCH R99, HSUPA,UL LTE) reflects only coverage dimensioning

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Models behind the development of the tool Other information, support

References

Agenda

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Where to find the tool, other information and which support?

All these tools and the related documents are available on a dedicated SharePoint

in Wireless Access. A dedicated support is ensured by Orange Labs/REM team

Sharepoint link: Link budgets

For support, contact: [email protected]; [email protected] &[email protected]

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Models behind the development of the tool Roadmap, next steps, other information, support

References

Agenda

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What are all the coverage dimensioning studies which were made

within Orange Labs with such tools and are available for MCOs?

Lots of studies had been provided with the Link Budget tools

# Study name Reference Project

[1] LTE Power impact - Link

budget analysis

RESA/NET/REM/10.286

Frdric Marache & Olfa Ben Haddada

Beyond 3G

[2] CoMP Technology in LTE-A

Link Budget and Capacity

Analyses

Results of Mame Fatou Gueye internship

January 2011

Research

[3] Coverage area for a target

throughput in HSDPA

/ RAN Engineering

[4] Gain of LTE relays Lee Rong , Olfa Ben Haddada & Salah El

Ayoubi, 2010

Beyond 3G

[5] HSDPA Link budget

comparison with Lab Tests

Christophe Simon, June 2011 RAN Engineering

[6] LTE 2600 vs 800 R. Nasri, Dec 2012 RAN Engineering

[7] Radio Link Budgets of Orange

Labs

PEAK/REM/ F. M, Sept 2012 RAN Engineering

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France Telecom group restrictedOrange Labs

Thank you

Documents

Radio Link Budget Tools