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LTE Network Planning

AGENDA

• LTE Network Planning Overview

• Frequency Planning

• Coverage Planning

• Capacity Planning

• End-user Demand Model

BASIC DESIGN PRINCIPLES OF RF SYSTEMS

• The coverage: area within which the RF signal has sufficient strength to meet QoS requirements.

• The capacity : ability of the system to support a given number of users. To improve coverage, capacity

has to be sacrificed, while to improve capacity, coverage will have to be sacrificed

• The QoS (i.e. performance): ability to adequately provide the desired services in the RF system.

With LTE, coverage, capacity, and QoS are all interrelated. To improve one of them, both the others (or at least one) have to be sacrificed.

Capacity

Coverage

QoS

PLANNING & DESIGN PHASES • High-level Planning: spreadsheet-based model of the RF link budget to estimate

the cell count required to meet capacity & coverage requirements, per clutter type (i.e. urban, sub-urban, rural….) and for each planning period. It does not include terrain effects.

• Detailed Design: requires an RF propagation tool and terrain database to model the characteristics of the selected antenna, the terrain, and the land use and land clutter surrounding the site. Produces a more accurate determination of the number of sites required, as well as detailed equipment configuration.

• Deployment Optimization: may include such items as collecting drive data to be used to tune or calibrate the propagation prediction model, predicting the available data throughput at each site, fine tuning of parameter settings (e.g. antenna orientation, downtilting, frequency plan).

This presentation covers the high-level planning phase.

Rural Suburban

High-Level Planning

End

BH Traffic per LTE Sub

Cell Capacity Total BH Traffic

Nbr Capacity Sites

Number of Sites

Number of LTE Subs

UL/DL Link Budget

Propagation Model

Nbr Coverage Sites

Cell-Edge QoS

Coverage Area

Frequency Planning

Planning Period 1

Dense-Urban

Urban

AGENDA






Frequency reuse mode 1*3*1

F1

F1 F1

F1

F1 F1

F1

F1 F1

F1

F1 F1

F1

F1 F1

F1

F1 F1

F1

F1 F1

Advantages of 1*3*1

Disadvantages of 1*3*1

• High frequency efficiency, High sector throughput

• Do not need complex scheduling algorithm, system

• Co-frequency interference is hard

• Low Cell edge data rate, difficulty for continuous coverage.

Used in limit frequency band and discontinuous coverage scenario

S111 BTS

SFR (Soft Frequency Reuse)1*3*1 SFR 1*3*1 with ICIC

SFR 1*3*1 networking merit

• DL ICIC：cell center use 2/3 band，cell edgeuse 1/3 band；so, in cell edge, frequency reuse 3, different cell edge use different frequency. Tx power in cell center lower than cell edge Tx power to control interference.

• UL ICIC： cell center use 2/3 band，celledge use 1/3 band, so, in cell edge, frequency reuse 3, different cell edge use different frequency. Cell users in same BTS transmit in the odd / even frame scheduling , respectively

• Lower down interference with ICIC

• High Frequency efficiency

DL SFR 1*3*1

UL SFR 1*3*1

Note: S111 BTS

Note: S111 BTS

ICIC - Inter-Cell Interference Coordination

SFR 1*3*1 Vs FFR 1*3*1 FFR 1*3*1 DL&UL

SFR1*3*1 DL SFR1*3*1 UL

Similarities

difference

• Separate by the frequency domain / time domain for interference cancellation

• Cell centers use more bandwidth resources, cell edge use of about 1 / 3 frequency bands,

• FFR use all the sub-carrier in cell center, SFR use 2/3 sub-carriers

• In DL/UL, FFR same reuse mode,, SFR use different mode

•DL Tx Power: SFR: cell center is lower than cell edge; FFR: cell center is same with cell edge

• UL frequency resource: FFR mode, in cell edge, fixed use 1/3 of the frequency band; In SFR mode, cell edge use partial band, normally near 1/3 of the frequency.

User in Cell center and cell edge within the cell separate by time domain，different site cell edge separate by frequency domain;

DL cell center decrease Tx powe；UL in cell edge，different cell separate in frequency domain， User in Cell center and cell edge within

the cell separate by time domain

Frequency reuse mode 1*3*3

Advantage of 1*3*3

Disadvantage of 1*3*3

•Low co-frequency interference, good coverage

• High sector throughput

• Low frequency efficiency

• More frequency resource required

Used in rich frequency resource and discontinuous frequency band coverage

S111 BTS

F3

F2 F1

F3

F2 F1

F3

F2 F1

F3

F2 F1

F3

F2 F1

F3

F2 F1

F3

F2 F1

Frequency Planning

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

F1

Advantages of 1*3*1

•High spectral efficiency and high sector throughput and capacity

• No frequency planning required

• Do not need complex scheduling algorithm

S111 eNodeB

Most LTE deployments (if not all) are using frequency reuse of 1 i.e. 1*3*1

Disdvantages of 1*3*1

•Co-frequency inter-cell interference at the celledge can be alleviated by frequency scheduling and the ICIC

Frequency Reuse Comparison

Frequency Po

wer

Frequency

Pow

er

Frequency

Pow

er

Cell 1 Cell 2 Cell 3

Hard Frequency Reuse

Frequency

Pow

er

Frequency

Pow

er

Frequency

Pow

er


Fractional Frequency Reuse

Frequency

Pow

er

Frequency

Pow

er

Frequency

Pow

er


Soft Frequency Reuse


Frequency Po

wer

Frequency

Pow

er

Frequency

Pow

er



• Sub-carriers are divided into disjoint sets

• Neighbouring cells don't use the same set of frequencies/sub-carriers

• User interference at cell edge is maximally reduced

• The spectrum efficiency drops by a factor equal to the reuse factor


• Cell space is divided into 2 regions: inner region & outer region (edge users)

• One section of the system spectrum is used in all cells

• Edge users are given orthogonal sub-bands

• SINR is significantly increased

• The bandwith is not fully used within one cell

• This scheme is particularly useful in the uplink

Frequency Po

wer

Frequency

Pow

er

Frequency

Pow

er




• Cell space is divided into 2 regions: inner region & outer region (edge users)

• Non-uniform power spectrum: edge users are given more power

• SINR is increased

• The bandwith is fully used within one cell

• This scheme is particularly useful in the downlink

Frequency Po

wer

Frequency

Pow

er

Frequency

Pow

er



AGENDA






Cell-edge QoS : SNR vs Bitrate

Source: 3GPP TS 36.213

Link Budget • Define all the gains and losses along the

RF path between the base station and the subscriber device (e.g. vehicle loss, building loss, ambient noise, transmit powers, receive sensitivities, antenna gains).

• Estimate a maximum allowable pathloss i.e. MAPL.

• With the MAPL, the propagation model can estimate site coverage, i.e. the number of sites required for adequate system RF signal coverage

The Rx Sensitivity and Tx Power can be expressed on either a per sub-carrier basis or per composite sub-carriers basis; but both

parameters must share the same reference.

The Link Budget is the accounting of all the losses and gains during a transmission inside the medium, antennas, cable etc. Basically the way to calculate the link budget is : Received Power = Transmitted Power + Gains – Losses.

• Estimate s a maximum allowable pathloss i.e. MAPL.

• With the MAPL, the propagation model can estimate site coverage, i.e. the number of sites required for adequate system RF signal coverage

Link Budget

Conventional LTE Link Budget The purpose of link budget in LTE network planning is: To use such factors as building penetration loss, feeder loss, antenna gain, and the interference Margin of radio links to calculate all gains and losses that will affect the final cell coverage To estimate the maximum link loss allowed based on the maximum transmit power of the terminal and eNodeB transmit power allocation. Coverage radius of a base station can be obtained according to the maximum link loss allowance under a certain propagation model. The radius can be used in subsequent design.

http://www.teletopix.org/tag/antenna

http://www.teletopix.org/tag/interference

Link budget parameters are grouped as follows: Propagation (Transmission) related parameters, such as the penetration loss, body loss, feeder loss, and background noise Equipment dependent parameters, such as the transmit power, receiver sensitivity, and antenna gain LTE-specific parameters, such as the pilot power boosting gain, Multiple Input Multiple Output (MIMO) gain, edge coverage rate, repeated coding gain, interference margin, and fast fading margin System reliability parameters, such as slow fading margin Specific features that will affect the final path gain

UE Transmit RF Power

UE Antenna Gain

eNodeB Antenna Gain

Other Gain Slow fading margin

Interference margin

Body Loss

eNodeB Cable Loss

Penetration Loss

Path Loss

eNodeB receive sensitivity

Link Budget Model: Uplink

Uplink Budget Gain

Margin

Loss

Path Loss

eNodeB Transmit Power

NodeB Antenna Gain

UE Antenna Gain


Interference margin

Body Loss

Cable Loss

Penetration Loss

Path Loss

UE receive sensitivity

Link Budget Model: Downlink

Downlink Budget Gain

Margin

Loss

Path Loss

Transmitter EIRP Example

Receiver Gains & Losses

Propagation Gains & Losses

PARAMETER VALUE DL UL Tx EIRP (dB) a 62 30

Rx EFS (dBm) b -107.8 -126.5

Body, Vehicle, Foliage, or Building Loss (dB) c 10 10

Interference Margin (dB) d 2 2

Log Normal Margin (slow fade) (dB) e 6.5 6.5

Maximum Allowable Pathloss (dB) f = a – b - c – d – e 151.3 138.0

RF Propagation Models

• HATA Model

• COST-231 HATA Model

• Erceg-Greenstein Model

HATA Model

Coverage Frequency (f): 150 MHz to 1500 MHz Mobile Station Height (Hm): between 1 m and 10 m Base Station Antenna Height (Hb): between 30 m and 200 m Link distance (d): between 1 km and 20 km.

COST-231 HATA Model

Coverage Frequency (f): 1.5 GHz to 2 GHz Mobile Station Antenna Height (Hm): 1 up to 10m Base Station Antenna Height (Hb): 30m to 300m Link Distance (d): 1 up to 20 km

Erceg-Greenstein Model • T errain A Hilly terrain with

moderate-to-heavy tree densities • T errain B Intermediate pathloss

condition • T errain C Mostly flat terrain with

light tree densities • Base Station Height (Hb) 10 to 80

m • Mobile Height (Hm) 2 to 10 m

Cell Count vs Link Budget

Any improvement in the link budget increases the cell size, and decrease the number sites required to cover a

given area.

Example: Frequency response

Channel coding/modulation

Output.

Link Level Simulator

System settings/Environment: • System BW • Channel (CIR, CFR) • Number of Antennas • PAPR, Synchronization, Channel estimation algorithms, etc

Inputs • User allocations • MCS • MIMO operation • User/control data

Outputs •Performance of channel coding/BER • EVM • Performance of algorithms •Visualization (Time and frequency plots, BER curves, MCS curves: throughput vs SNIR)

Provides the possibility to adjust/evaluate: - algorithms of sync, channel estimation, - application in various channel conditions, - RF emission, filtering

Input data

Output.

System settings

Radio Channel

Sync/Estim

Channel decoding Output.

Tools in the Planning Process

Link Level Simulator

wwwwww.i.iss--wwiirerelleessss.c.coomm

•Coverage (field strength, Rx power level, best server) • Capacity (interference, SNIR, data rates) •Visualization (coverage/capacity maps, statistics)

Example: SINR map

RNP Tool

System settings/Environment: • Chosen and tuned propagation models • Chosen and tuned traffic models • Geographical data – digital map (elevation, land usage, …)

Inputs • Site locations and configuration • Antenna models (patterns) • Available frequencies and BWs • Spectrum reuse method • MCS mapping (from Link Level)

Outputs

Usually Static Simulations Provides the possibility to adjust/evaluate: -Site locations, powers, spectrum reuse methods, frequency planning, - parameter configuration.

Pathloss

Rx_Lev

Best server

C/I

Bit/rates

Network parameters Map

MCS mapping

Output.

Output.

Output.

Output.

Output.

Tools in the Planning Process RNP Tool

http://www.i.iss--wwiirerelleessss.c.coomm/

































System Level Simulator

System settings/Environment: • System BW • System parameters configuration (CellIDs, frequencies) • Channel, traffic, user distribution models, etc

Inputs • Coverage (from RNP tool) • Capacity (from RNP tool) • Site location (from RNP tool) • QoS • User positions • RRM algorithms

Outputs •Utilization of resources •Dynamic/Semi-static coverage/SNIR/Bitrates • Blocked users • Visualization (SNIR/Spectral efficiency, resource utilization) • Mobility performance

Example: Spectral efficiency

Usually Dynamic Simulations Provides the possibility to adjust/evaluate: - different RRM algorithms, - power control algorithms - traffic shaping methods, - interference management schemes - fade margins, UE power margins

UE position

Random fading

Conn. Est.

Power/datarate

Interference

Input from RNP Traffic demands/QoS

RRM alg.

Output.

Output.

Pos

ition

adj

ustm

ent

Tools in the Planning Process System Level Simulator

Link budget

Pr = Pt + GAINS - LOSSES - MARGINS

Question: what is the cell edge criterion?

Pt

TX

SNIR

RX

Pr

P_sens

GAINS, LOSSES, MARGINS

Distance d - Max throughput at the cell edge - Basic connectivity (i.e., lowest possible

MCS) - Ref RX sensitivity requirement

SNIR_min

LTE Link Budget General Rules

eNB TX

UE RX

LTE Link Budget Example Link Budget in Downlink

Parameter Value Comment

A Max eNB TX power 46 dBm

B Cable loss 3 dB

C CP loss 1 dB

D eNB antenna gain max 19 dBi

E EIRP max 61 dBm = A – B – C + D

BW_RX 1.8 MHz

F Noise power -102 dBm

G SNIR_min 5 dB From MCS tables

H UE antenna gain 0 dBi

I Min required RX power -97 dBm = F + G - H

J total path loss 158 dBm = E – I

K Other gains, losses, margins - 10 dB Shadowing, fast fading, multiantenna

L Maximum Allowed Propagation Loss 148 dBm = J + K

Cell range 3.5 km

After determiation of cell range (radius) d we can estimate the site coverage area

GRID to be entered into the RF Planning tool for verification

* Source: J. Laiho, A. Wacker, T. Novosad, „Radio Network Planning and Optimization for UMTS”, Wiley, 2002, pp 83

#sites = deployment_area / site_area

LTE Coverage Site Coverage Area and Inter-Site Distance

* Omni 2-sectors 3-sectors

Site_area 2.6 * d2 1.3 * d2 1.95 * d2

Intersite_distance 0.87 * d 2* d 1.5 * d

Link Budget Procedure

Start

End

Input Data

Calculate UL/DL MAPL

Calculate UL cell radius Calculate DL cell radius

Balance cell radius

Calculate site number

Calculate site coverage area

Presenter

Presentation Notes

Same as other system Site number is determined by effective cell radius

UE Transmit Power

UE Antenna Gain

eNodeB Antenna Gain


Interference margin

Body Loss

eNodeB Cable Loss

Penetration Loss

Path Loss


Cable Loss

Antenna Gain


Penetration Loss

Link Budget Model: Uplink

UE transmit power

Uplink Budget Gain

Margin

Loss Path Loss

Presenter

Presentation Notes

effective cell radius is determined by path loss

eNodeB Transmit Power

NodeB Antenna Gain

UE Antenna Gain


Interference margin

Body Loss

Cable Loss

Penetration Loss

Path Loss


Link Budget Model: Downlink

Cable Loss

Antenna Gain

eNodeB transmit power

Penetration Loss


Downlink Budget Gain

Margin

Loss

Path Loss

Link Budget Principle • Link budget is aim to calculate the cell radius.

Cell radius can be calculated by MAPL with using propagation model

• Two keys factors: MAPL Propagation Model

MAPL: Maximum Allowed Path Loss EIRP: Effective Isotropic Radiated Power MSSR: Minimum Signal Strength Required

CmHaLuTotal UE +−= )()lg())lg(55.69.44()lg(82.13)lg(9.333.46 dHHfLu BSBS ××−+×−×+=

)8.0)lg(56.1()7.0)lg(1.1()( −×−×−×= fHfHa UEUE

Cost231-Hata Model

MAPL = EIRP - Minimum Signal Strength Required+ ∑Gain - ∑Loss - ∑Margin

EIRP = Max Tx Power - Cable Loss - Body Loss + Antenna Gain MSSR = Rx Sensitivity - Antenna Gain + Cable Loss + Body Loss + Interference Margin

Presenter

Presentation Notes

Rx Sensitivity Composite (Final Result) = Rx Sensitivity Per Sub-carrier +10lg(Sub carrier Number) Rx Sensitivity Per Sub-carrier = Thermal noise + 10lg(Sub carrier band)+ NF + SINR Thermal noise: -174dBm/Hz eNodeB Noise Figure: 2.1dB UE Noise Figure: 7dB

AGENDA






– Signaling Overhead – UE mobility – Slow/fast fading – Power control – –

Scheduling …

Site Capacity – Spectral Efficiency Downlink Spectral Efficiency

• Based on Spectral Efficiency (*) • Simulation takes into account

• Results available – Per spectrum bands – Per channel bandwiths – Per inter-site distance

(*) figures obtained from dynamic system level simulations (vendor-specific)

SE figures can be interpolated for specific ISD and bands, and additional scaling factors applied

Uplink Spectral Efficiency

Overhead Channels - DL • Physical Downlink Shared Channel (PDSCH) – Carries DL data and higher layer signalling. The

PDSCH is allocated to different UEs usually every 1ms. PDSCH channel coding, modulation andsub-carrier allocation is dynamically controlled by the PDCCH (uses QPSK, 16QAM and64QAM);

• Physical Downlink Control Channel (PDCCH) – Informs UE about resource allocation for PCH and DL-SCH, plus the HARQ information relating to the DL-SCH. Also controls UL-SCH scheduling grants and indicates the UE identity (uses QPSK);

• Physical Broadcast Channel (PBCH) - DL channel that carries system broadcast traffic (uses QPSK),

• Physical Control Format Indicator Channel (PCFICH) – Transmitted every sub-frame to inform the UE about the number of OFDM symbols used for the PDCCH channel (uses QPSK);

• Physical Hybrid ARQ Indicator Channel (PHICH) - Carries hybrid ARQ (HARQ) ACKs or NACKs for UL transmissions on the PUSCH (uses BPSK); and

• Physical Multicast Channel (PMCH) – Carries the MBMS data and control if the cell supports MBMS functionality (uses QPSK, 16QAM and 64QAM).

Overhead Channels - UL • Physical Random Access Channel (PRACH) – Carries random access

preambles used when the UE makes initial contact with the network;• Physical Uplink Shared Channel (PUSCH) – Carries uplink data and higher

layer signalling. PUSCH is a shared channel allocated to different UEsusually every 1ms. The channel coding, modulation and sub-carrierallocation is dynamically controlled by the PDCCH (uses QPSK, 16QAM and64QAM) and

• Physical Uplink Control Channel (PUCCH) – Carries UL control information for a UE including CQI, HARQ, ACKs and NACKs, and UL scheduling requests (depending on format, PUCCH may use BPSK or QPSK).

Overhead Channels – UL & DL

Average Cell Throughput for LTE

Coverage & Capacity Baseline

Scenario Cell Radius (km) @ UL edge 64~512kbps Avg. Cell Throughput DL/UL (Mbps) @10MHz BW

2.6GHz 2.1GHz AWS 700MHz 2.6GHz 2.1GHz AWS 700MHz

Dense Urban 0.21~0.33 0.26~0.4 0.3~0.46 0.66~1.01 16.92 / 9.76 18.39 / 10.61 17.62 / 10.87 17.35 / 12.17

Urban 0.39~0.58 0.47~0.71 0.55~0.82 1.20~1.79 16.92 / 9.76 18.39 / 10.61 17.62 / 10.87 17.35 / 12.17

SubUrban 1.47~2.25 1.8~2.76 2.09~3.2 4.61~7.06 12.97 / 6.92 14.10 / 7.52 16.82 / 8.70 17.27 / 10.67

Rural 3.16~4.83 4.42~5.93 4.78~7.3 9.48~14.51 12.97 / 6.92 14.10 / 7.52 16.82 / 8.70 17.27 / 10.67

Throughput Calculation Example - PDSCH

No of RB MCS I_TBS TBS SISO 2X2 MIMO

6 28 26 4392 4.19 8.38

15 28 26 11064 10.55 21.10

25 28 26 18336 17.49 34.97

50 28 26 36696 35.00 69.99

75 28 26 55056 52.51 105.01

75 27 25 46888 44.72 89.43

100 28 26 75376 71.88 143.77

100 23 21 51024 48.66 97.32

100 20 18 39232 37.41 74.83

From TS36.213 Table 7.1.7.1-1

From TS36.213 Table7.1.7.2.1

TBS : Transport Block Size (bits)

Channel Bitrate (Mbps) = TBS * 1000 / (1024*1024)

AGENDA






Traffic Models Changing with LTE

• Increased bandwidth leads to a more demanding user:

GB per month = (Mbps link speed)0.7 x 1.2

• Daily distribution of data traffic is flatter than that of voice traffic

7% of daily volume

• The Internet has become more and more symmetric between downlink and uplink now is approximately 55%/45% downlink/uplink

Volume per Day (3G vs LTE)

Traffic Variations : OS & Device

Traffic Variations : apps & data plan

UL/DL Daily Pattern vs Apps

Source : Ericsson 2012

Monthly Traffic (MB/Month)

DEVICE 2011 2012 2017

Smartphone 250 350 1,100

PC 2,000 2,500 8,000

Tablet 650 850 3,200

Fixed Broadband 35,000 50,000 140,000

Source: 3GPP TS 36.306

LTE Device Categories

Release-10 Categories

UE Category

Peak Datarate (Mbps)

Modulation Max RF Bandwith

(MHz)

MIMO (Max)

DL UL DL UL DL DL

1 10 5 QPSK, 16QAM, 64QAM QPSK, 16QAM 20 1X1




5 300 75 QPSK, 16QAM, 64QAM QPSK, 16QAM, 64QAM 20 4x4

6 300 50 QPSK, 16QAM, 64QAM QPSK, 16QAM 20-40 4x4

7 300 150 QPSK, 16QAM, 64QAM QPSK, 16QAM 20-40 4x4

8 1200 600 QPSK, 16QAM, 64QAM QPSK, 16QAM, 64QAM 20-40 8X8

Applicable Standards

• 3GPP TS 36.101: User Equipment (UE) radio transmission and reception • 3GPP TS 36.213: Physical layer procedures • 3GPP TS 36.306: User Equipment (UE) radio access capabilities

THANK YOU

lte network · pdf file• lte network planning overview ... fine tuning of parameter...

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