Dimensioning of LTE Network
Description of Models and Tool, Coverage and
Capacity Estimation of 3GPP Long Term Evolution
radio interface
Abdul Basit, Syed
Masters Thesis submitted in partial fulfillment of the requirements for the
Degree of Masters of Science in Technology
Espoo, February, 2009
Supervisor:
Professor Riku Jäntti
Instructor:
Paolo Zanier
-
DEDICATION
To
Prophet of Islam
MUHAMMAD
(Peace and blessings of God be upon him)
ii
HELSINKI UNIVERSITY OF TECHNOLOGY
Abstract of the Master’s Thesis
Author:
Abdul Basit, Syed
Name of Thesis:
Dimensioning of LTE Network. Description of Models and Tools,
Coverage and Capacity Estimation of 3GPP Long Term Evolution
Date:
20.02.2009
Number of Pages: 71
Department:
Department of Electrical and Communications Engineering
Professorship:
S-72 Communications Laboratory
Supervisor:
Professor Riku Jäntti
Instructor:
Paolo Zanier
Long Term Evolution (LTE) is 3GPP enhancement to the current cellular system in use.
The purpose of developing this system is to keep 3GPP systems competent enough for
decades to come. LTE is designed to have wider channels up to 20MHz, with low latency
and packet optimized radio access technology. The peak data rate envisaged for LTE is
100 Mbps in downlink and 50 Mbps in the uplink. With OFDM as the radio access
technology, LTE has very promising features, like bandwidth scalability and both FDD
and TDD duplexing methods. This thesis is related to the dimensioning of LTE radio
access networks and the development of tool for dimensioning purpose.
Different steps of the dimensioning process are listed and explained. Methods and models
for coverage and capacity planning are developed for dimensioning of LTE radio access
networks. Special emphasis is laid on radio link budget along with detailed coverage and
capacity. The results are fabricated in an easy-to-use tool for dimensioning. The tool is
made in Excel to serve the ease of working.
Particular importance is given to clarity in the design of dimensioning tool, achieved by
dividing the tool into clearly defined sections. Inputs and outputs are placed on separate
sheets. The dimensioning tool calculates the number of cells needed to cover a given area
with the user-provided parameters. Excel based tool covers all the basic aspects of the
dimensioning process for LTE Access Networks.
Keywords: 3GPP, LTE, Dimensioning, Network Planning, Capacity, Traffic Models.
iii
Table of Contents
Table of Contents.......................................................................................................... iii
Acknowledgments...........................................................................................................v
List of Abbreviations ......................................................................................................vi
List of Figures................................................................................................................ix
List of Tables .................................................................................................................ix
1
Introduction ........................................................................................................... 1
1.1
Objectives and Approach ................................................................................................. 2
1.1.1
Methodology........................................................................................................................2
1.1.2
Dimensioning Tool.............................................................................................................4
1.2
Thesis Layout ..................................................................................................................... 4
2
Long Term Evolution of 3GPP (LTE) and Dimensioning......................................5
2.1
LTE Overview.................................................................................................................... 6
2.2
Requirements for LTE ...................................................................................................... 6
2.3
Multiple Access Techniques............................................................................................. 7
2.3.1
OFDMA for DL .................................................................................................................8
2.3.2
SC-FDMA for UL ............................................................................................................11
2.4
Bandwidth Scalability ...................................................................................................... 12
2.5
Network Architecture ..................................................................................................... 13
2.6
E-UTRAN Interfaces...................................................................................................... 15
3
Dimensioning of LTE Network............................................................................ 17
3.1
Wireless Cellular Network Dimensioning.................................................................... 17
3.2
LTE Access Network Dimensioning............................................................................ 21
3.2.1
Inputs of LTE Dimensioning .........................................................................................22
3.2.2
Outputs of LTE Dimensioning......................................................................................23
3.2.3
LTE Dimensioning Process ............................................................................................23
4
Coverage Planning and Radio Link Budget.......................................................... 27
4.1
Radio Link Budget ........................................................................................................... 28
iv
4.1.1
Other-to-own cell interference (i) ..................................................................................32
4.2
Required SINR ................................................................................................................. 33
4.2.1
Spectral Efficiency ............................................................................................................33
4.3
Interference....................................................................................................................... 36
4.4
Coverage-based Site Count ............................................................................................ 38
5
Capacity Planning ................................................................................................ 40
5.1
LTE Capacity Planning ................................................................................................... 40
5.2
Average Cell Throughput Calculations......................................................................... 41
5.3
Traffic demand estimation and Overbooking factor.................................................. 43
5.4
Capacity based site count................................................................................................ 44
6
Tool for LTE Dimensioning................................................................................. 45
6.1
Methodology and Structure............................................................................................ 45
6.2
Dimensioning inputs ....................................................................................................... 46
6.3
Tables and background data........................................................................................... 48
6.4
Radio link budget ............................................................................................................. 50
6.5
Capacity Evaluator........................................................................................................... 52
6.6
Dimensioning Output ..................................................................................................... 53
7
Conclusion and Future Work ................................................................................ 56
7.1
Conclusion ........................................................................................................................ 56
7.2
Future Work ..................................................................................................................... 57
8
References ............................................................................................................ 58
v
Acknowledgments
This Master’s thesis was completed at Nokia Oyj during the period of June 2006 – January 2007.
I am deeply indebted to Dr. David Soldani and Paolo Zanier, who has been my instructors for
this work. I am grateful for their cooperation, encouragement and invaluable guidance
throughout the thesis. I must extend my gratitude to my supervisor, Professor Riku Jäntti for
being always so supportive and cooperative.
I am deeply and forever obliged to my family for their love, support and encouragement
throughout my entire life.
I am thankful to all my colleagues at Nokia for extending their technical support and advice
during the work, especially Murad Keskinege, Flavio Parodi, Mikko Kylvaya, Paolo Zanier, Jose
Alonso-Rubio and Michael Abromowski.
At the end, my sincere thanks go to my friends and seniors at HUT for their help and
motivation.
Syed, Abdul Basit
Espoo, February 2009
vi
List of Abbreviations
2G
2nd Generations
3G
3rd Generations
3GPP
3rd Generation Partnership Project
ACK
Acknowledgment
aGW
Access Gateway
ARIB
Association of Radio Industries and Businesses
ATIS
Alliance for Telecommunications Industry Solutions
ANSI
American National Standards Institute
BCCH
Broadcast Control Channel.
BW
Bandwidth
CAPEX
Capital expenses
CCPCH
Common Control Physical Channel
CCSA
China Communications Standards Association
CDF
Cumulative Distribution Function
CDMA
Code Division Multiple Access
CN
Core Network
CP
Cyclic Prefix
CQI
Channel Quality Indicator
DL
Downlink
DSCH
Downlink Shared Channel
DVB-H
Digital Video Broadcast - Handhelds
E-UTRAN
Enhanced – UMTS Terrestrial Radio Access Network
eNB
Enhanced Node B
EPC
Evolved Packet Core
eSFN
Enhanced System Frame Number
ETSI
European Telecommunications Standard Institute
FDD
Frequency Division Duplex
FDMA
Frequency Division Multiple Access
GSM
Global System for Mobile
GPRS
General Packet Radio System
vii
GGSN
Gateway GPRS Support Node
HSDPA
High Speed Downlink Packet Access
HSPA
High Speed Packet Access
HSUPA
High Speed Uplink Packet Access
HS-DSCH
High Speed Downlink Shared Channel
HS-PDSCH
High Speed Physical Downlink Shared Channel
HS-SCCH
High Speed Shared Control Channel
IP
Internet Protocol
IETF
Internet Engineering Task Force
L1
Layer 1
L2
Layer 2
LB
Long Block
LTE
Long Term Evolution
MAC
Medium Access Control
MBMS
Multimedia Broadcast Multicast Service
Mbps
Megabits per second
MCS
Modulation Coding Scheme
MME
Mobility Management Entity
MSC
Mobile Switching Centre
NFFT
Number of Samples of FFT
OBF
Overbooking Factor
OFDM
Orthogonal Frequency Division Multiplexing
OFDMA
Orthogonal Frequency Division Multiple Access
OPEX
Operating Expenses
PBCH
Physical Broadcast Channel
PCRF
Policy and Charging Rules Function
PDCCH
Physical Downlink Control Channel
PDCP
Packet Data Convergence Protocol
PDF
Probability Distribution Function
PDSCH
Physical Downlink Shared Channel
PHY
Physical Layer
PS
Packet Switched
PDSCH
Physical Downlink Shared Channel
viii
PDSCCH
Physical Downlink Shared Control Channel
PUCCH
Physical Uplink Control Channel
PUSCH
Physical Uplink Shared Channel
QAM
Quadrature Amplitude Modulation
QoS
Quality of Service
QPSK
Quadrature Phase Shift keying
RAN
Radio Access Network
RB
Resource Block
RLB
Radio Link Budget
RLC
Radio Link Control
RNC
Radio Network Controller
RRC
Radio Resource Control
SAE
System Architecture Evolution
SB
Short Block
SFN
System Frame Number
SGSN
Serving GPRS Support Node
SINR
Signal to Interference and Noise Ratio
SISO
Single Input Single Output
SNR
Signal to Noise Ratio
SC-FDMA
Single Carrier-Frequency Division Multiple Access
SCTP
Stream Control Transmission Protocol
TDD
Time Division Duplex
TE
Terminal Equipment
TTA
Telecommunications Technology Association
TTC
Telecommunication Technology Committee
TTI
Transmission Time Interval
UE
User Equipment
UL
Uplink
UMTS
Universal Mobile Telecommunication System
UPE
User Plane Entity
UTRAN
UMTS Terrestrial Radio Access Network
U-plane
User Plane
WCDMA
Wideband Code Division Multiple Access
WiMAX
Worldwide Interoperability for Microwave Access
ix
List of Figures
Figure 1-1: Flow chart of Project Work ----------------------------------------------------------------------------------- 3
Figure 2-1: OFDM Symbol Time Structure [11] ------------------------------------------------------------------------- 9
Table 2-1: Physical Layer parameters [11] ------------------------------------------------------------------------------- 9
Figure 2-2: Downlink frame structure for frames with short cyclic prefix [11] -------------------------------------10
Figure 2-3: Downlink frame structure for frames with long cyclic prefix [11] --------------------------------------11
Figure 2-4: UL Frame Structure for LTE [11]---------------------------------------------------------------------------11
Table 2-2: UL Physical Layer Parameters [11] -------------------------------------------------------------------------12
Figure 2-5: E-UTRAN Architecture [4] -----------------------------------------------------------------------------------13
Figure 2-6: E-UTRAN Interfaces [4]--------------------------------------------------------------------------------------15
Figure 3-1: General wireless cellular network planning process -----------------------------------------------------18
Figure 3-2: General radio link budget of a wireless cellular network [31] ------------------------------------------20
Figure 3-3: LTE network dimensioning -----------------------------------------------------------------------------------24
Figure 4-1: LTE spectral efficiency as function of G-factor (in dB) including curves for best Shannon fit [21] 35
Figure 4-2: CDF for G-factors of an LTE system (with different scenarios)[21] -----------------------------------36
Table 4-1: load versus Interference margin ------------------------------------------------------------------------------37
Figure 4-3: load versus Interference margin ----------------------------------------------------------------------------38
Figure 4-4: Three different types of sites (Omni-directional, bi-sector, tri-sector) ---------------------------------38
Table 5-1: DL average cell throughput for LTE -------------------------------------------------------------------------42
Figure 6-1: Dimensioning tool: Capacity Inputs ------------------------------------------------------------------------47
Figure 6- 2: Dimensioning tool: Coverage Inputs -----------------------------------------------------------------------48
Figure 6- 3: Dimensioning tool: Traffic models -------------------------------------------------------------------------49
Figure 6-4: Dimensioning tool: Capacity evaluator --------------------------------------------------------------------51
Figure 6-5: Dimensioning tool: Capacity evaluator --------------------------------------------------------------------52
Figure 6-6: Dimensioning tool: Forecast---------------------------------------------------------------------------------53
Figure 6-7: Dimensioning tool: Outputs ----------------------------------------------------------------------------------55
List of Tables
Table
2-1: Physical Layer parameters [11].......................................................................................................... 9
Table
2-2: UL Physical Layer Parameters [11] ................................................................................................. 12
Table
4-1: load versus Interference margin........................................................................................................ 37
Table
5-1: DL average cell throughput for LTE ................................................................................................. 42
1
1
Introduction
Telecommunication industry is experiencing the emergence of a number of competing and
enhancing technologies, including, WiMAX, HSPA, DVB-H. With the user requirements on the
ever increasing side cellular networks are facing greater than ever competition from other
technologies. HSPA (High speed packet access) and MBMS (multimedia broadcast and
multicast service) has enhanced the 3G networks by bringing important capabilities, but these
improvements are still not enough to match broadcasting technologies (such as DVB-H) or
broadband wireless access (like WiMAX) for delivering modern services, e.g. mobile TV,
internet access and other important services[1]. Therefore, 3G networks need a major overhaul
to remain competitive in the future.
In order to stay competitive in the long run, 3GPP (Third generation partnership project) has
initiated activity on the long term evolution of UTRAN (Universal Terrestrial Radio Access
Network), which is eyeing clearly beyond to what the WCDMA can do with HSDPA or High
Speed Uplink Packet Access (HSUPA). 3GPP’s answer to this demanding situation is 3G LTE
(Long term evolution) or Super 3G, which could dramatically boost the capabilities of 3G
networks and make it par with the other technologies [2].
2
LTE is a system with larger bandwidths (up to 20 MHz), low latency and Packet optimized radio
access technology having peak data rates of 100 Mbps in downlink and 50 Mbps in the uplink
[3,4]. Radio access technology for LTE is OFDM (Orthogonal frequency division multiplexing)
which provides higher spectral efficiency and more robustness against mulitpath and fading, as
compared to CDMA (Code division multiple access). In order to offer the operators increased
flexibility in network deployment, the LTE system supports bandwidth scalability and both
FDD and TDD duplexing methods. The system also supports both unicast and multicast traffic
– in cell sizes from local area or micro cells (hundreds of meters) up to large macro cells (>10
km in radius) [4,5]. 3GPP is looking for market introduction of LTE around 2012.
1.1
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