LTE Planning
Transcript of LTE Planning
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3GPP Time Line and Evolution
LTE Requirement (3GPP TR 25.913)
• Peak data rate 100 Mbps (DL) and 50 Mbps (UL) to 20 MHz
• Throughput increased by 3-4 times and 2-3 times for the downlink to uplink from HSDPA Rel 6 ( DL =
14.4 Mbps , to use transmitter sites that have been used in UTRA / GERAN
• Throughput increased by 3-4 times and 2-3 time UL = 5.7 Mbps )
• Spectrum efficiency by continuing as for the downlink to uplink from HSDPA Rel-
6 (DL = 14.4 Mbps, UL = 5.7 Mbps)
• Flexible use of spectrum (1.4, 3, 5, 10, 15, 20 MHz)
• Lower latency :
– Radio access network latency ( user plane UE – RNC- UE ) below 10 ms
• The ability of the use mobility up to 350 km / hour
• Coverage up to a radius of approximately 5 km
• Enhance MBMS ( Multimedia Broadcast / Multicast Service ) efficiency ( 1 bit/s/Hz)
• Retaining 3GPP RAT ( Radio Access Technology ) which already exist and support internetworking with
him.
• Architecture simplification , minimization and packet – based interface , full IP
LTE Architecture
In the LTE network is divided into
2 basic network, namely:
1. E UTRAN (Evolved Universal
Terrestrial Radio Access Network)
2. EPC (Evolved Packet Core)
SERVICE
The IP Multimedia Sub-System (IMS) is a good example of servicemachinery that can be used in the Services Connectivity Layer toprovide services on top of the IP connectivity provided by the lowerlayers.
For example, to support the voice service, IMS can provide Voice overIP (VoIP) and interconnectivity to legacy circuit switched networksPSTN and ISDN through Media Gateways it controls.
EPC
• Functionally the EPC is equivalent to the packet switched domain of theexisting 3GPP networks.
• EPC consist of :
– MME ( Mobility Management Entity )
– SAE GW represents the combination of the two gateways, ServingGateway (S-GW) and Packet Data Network Gateway (P-GW)
– Home Subscriber Server (HSS)
– Policy and Charging Rules Function (PCRF)
( Evolved Universal Terrestrial Radio Access Network)
Mobility Management Entity (MME)
– MME is a controller at each node on the LTE access network. At UEin idle state (idle mode), MME is responsible for tracking andpaging procedure which includes retransmission therein.
– MME is responsible for selecting SGW (Serving SAE Gateway)which will be used during initial attach EU and the EU time to dointra - LTE handover.
– Used for bearer control, a different view R99 / 4 which is stillcontrolled by the gateway
Policy and Charging Rules Function (PCRF)In order to handle QoS as well as control rating and charging, and billing
EPC Con’t
Home Subscriber Server (HSS)For management and security subscriber, combination AUC and HLR
Serving SAE Gateway (SGW)
- Set the path and forwards the data in the form of packets of each user- As an anchor / liaison between the UE and the eNB at the time of the inter handover
- As a liaison link between the 3GPP LTE technology with the technology(in this case the 2G and 3G)
Gateway Packet Data Network (PDN GW)
- Provides for the UE 's relationship to the network packet- Provide a link relationship between LTE technology with technology non 3GPP (WiMAX) and 3GPP2 (CDMA 20001X and EVDO)
EPC Con’t
E-UTRAN
Role of Radio Access Network (RAN), namely Node B and RNC is
replaced with ENB, so as to reduce operational and maintenance cost
of the device other than the simpler network architecture
E-nodeB functions : all radio protocols, mobility management, header
compression and all packet retransmissions
As a network, E-UTRAN is simply a mesh of eNodeBs connected to
neighboring eNodeBs with the X2 interface.
(Evolved Universal Terrestrial Radio Access Network)
User Equipment
Functionally the UE is a platform for communicationapplications, which signal with the network for settingup, maintaining and removing the communication linksthe end user needs.
This includes mobility management functions such ashandovers and reporting the terminals location, and inthese the UE performs as instructed by the network
FREQUENCY & BANDWIDTH IN LTE
Key Consideration to Spectrum Selection
* Band Selection Source: 3GPP TS 36.101
Illustration for Spectrum Selection
Channel Bandwidth Flexibility
LTE provides channel bandwidth flexibility for operation in differently-sized
LTE supports paired and unpaired spectrum on the same hardware spectrum
Channel Bandwidth Impact
OFDM
OFDM vs Single Carrier
Spectral efficiency of OFDM compared to classicalmulticarrier modulation: (a) classical multicarriersystem spectrum; (b) OFDM system spectrum.
Motivation for OFDM Approaches• Advantages
– Efficient in the use of frequencies
– Highly scalable
– Overcome delay spread, multipath & frequency selective fading, and ISI
• Weaknesses– Frequency Offset
– Nonlinear Distortion (PAPR)
PAPR illustration
OFDM Concept
• Multicarrier modulation/multiplexing technique• Available bandwidth is divided into several sub-channels• Data is serial-to-parallel converted• Symbols are transmitted on different sub-channels
OFDM Block Diagram (Tx)
Diagram Block Contents:
• S/P Serial to Parallel Converter
• Sub-Carrier Modulator
• IFFT Inverse Fast Fourier Transform
• P/S Parallel to Serial Converter
• DAC Digital to Analog Converter
OFDM Block Diagram (Rx)
Diagram Block Contents:
• S/P Serial to Parallel Converter
• Sub-Carrier Modulator
• IFFT Inverse Fast Fourier Transform
• P/S Parallel to Serial Converter
• DAC Digital to Analog Converter
Cyclic Prefix• Useful for multipath delay spread• Guard Interval (cyclic prefix) : short & long
Type of Cyclic Prefix
OFDMA & SC-FDMA
OFDMA vs. SCFDMA Definition
OFDMA is a multiple access technique based on OFDM as the modulation technique. It is used for DL transmission in LTE
SC-FDMA is a hybrid UL transmission scheme in LTE which has single-carrier transmission systems with the long symbol time and flexible frequency allocation of OFDM.
SC-FDMA Diagram Block
SC-FDMA frequency-domain transmit processing (DFT-S-OFDM) showing localized and distributed subcarrier mappings.
Type of OFDMA Sub-Carrier
Data sub-carrier
– Carry QPSK, 16 QAM, 64 QAM symbol
Pilot sub-carrier
– It is used to facilitate channel estimation and coherent demodulation at the receiver
Null sub-carrier
– Guard sub-carrier
– DC sub-carrier
Subcarrier Mapping
(Npilot -2)/2 Nsubcarrier data / 2
PIL
OT
Nsubcarrier data / 2 Npilot /2
BW
Nsubcarrier data See slide #19 or 3GPP TS 36.104Npilot NFFT-Point - Nsubcarrier data
MULTI ANTENNA TECHNIQUE
Multiple Antenna Technique
Existing Tech Smart Antenna MIMO Antenna
Multiple Antenna Technique Two popular techniques in MIMO wireless systems:
Spatial Diversity: Increased SNR• Receive and transmit diversity
mitigates fading and improves link quality
Spatial Multiplexing: Increased rate• Spatial multiplexing yields
substantial increase spectral efficiency
Spatial DiversityTransmit Diversity
• Space-time Code (STC): Redundant data sent over time and space domains (antennas).
• Receive SNR increase about linearity with diversity order NrNt
• Provide diversity gain to combat fading
• Optional in 802.16d (2x2 Alamouti STBC), used in 3G CDMA
Spatial Multiplexing
MIMO Multiplexing
• Data is not redundant – less diversity but less repetition
• Provides multiplexing gain to increase data-rate
• Low (No) diversity compared with STC
LTE SUPPORTING TECHNOLOGIES
HARQ
AMC
HARQ
HARQ or retransmission scheme in LTE use stop-and-wait retransmission system.
Adaptive Modulation
SNR-CQI Mapping for BLER 10%
Adaptive Modulation Illustration
Constellation DiagramQPSK
16 QAM
64 QAM
Adaptive Modulation and Coding
Standard for CQI mapping
Scheduling
Control PlaneControl Plane (C-Plane) is use to describe the protocols that convey information from the DTE to the end user (the control) of a node, or between nodes in the network to conveying required information to set, control and clearing the connection protocol.
User plane (U-plane) is a protocol used directly in the transfer of user data from the DTE (Data Terminal Equipment) to the other end-users. U-plane provides the function of delivery or transfer user information, and include all relevant mechanisms of information transfer such as flow control and error recovery. In the user plane used approach layer .
User Plane
CONTROL PLANE
USER PLANE
LTE CHANNELS
LTE Layer Mapping
Layer Function• Radio Link Control Layer (RLC)
> Retransmission
> Segmentation
• Medium Access Control Layer (MAC)
> Uplink and downlink scheduling at the eNodeB
> HARQ
• Physical Layer (PHY)
> Modulation/demodulation
> Coding/decoding
LTE Downlink Channel Mapping
LTE Downlink Logical Channels
• Paging Control Channel ( PCCH)> A downlink channel that transfers paging information and system
information change notifications.> This channel is used for paging when the network does not know
the location cell of the UE
• Broadcast Control Channel (BCCH)> Provides system information to all mobile terminals connected to
the eNodeB.> A downlink channel for broadcasting system control information
• Common Control Channel (CCCH)
> Channel for transmitting control information between UEs andnetwork.
> This channel is used for UEs having no RRC connection with thenetwork.
• Multicast Control Channel (MCCH)> A point-to-multipoint downlink channel used for transmitting MBMS
> Control information from the network to the UE, for one or severalMTCHs.
> This channel is only used by UEs that receive MBMS
• Dedicated Control Channel (DCCH)> A point-to-point bi-directional channel that transmits dedicated
control information between a UE and the network.
> Used by UEs having an RRC connection
> This control channel is used for carrying user-specific controlinformation, e.g. for controlling actions including power control,handover, etc..
LTE Downlink Logical Channel Con’t
LTE Downlink Logical Channel Con’t
• Multicast Traffic Channel (MTCH)
> A point-to-multipoint downlink channel for transmitting traffic data
from the network to the UE.
> This channel is only used by UEs that receive MBMS
• Dedicated Traffic Channel (DTCH )
> A point-to-point channel, dedicated to one UE, for the transfer of
user information.
> A DTCH can exist in both uplink and downlink
LTE Downlink Transport Channel
• Paging Channel ( PCH)> Supports UE discontinuous reception (DRX) to enable UE power
saving
> Broadcasts in the entire coverage area of the cell;
> Mapped to physical resources which can be used dynamically alsofor traffic/other control channels.
• Broadcast Channel ( BCH )
> The LTE transport channel maps to Broadcast Control Channel
(BCCH)
> Fixed, pre-defined transport format
> Broadcast in the entire coverage area of the cell
• Multicast Channel ( MCH)
> Broadcasts in the entire coverage area of the cell;
> Supports MBSFN combining of MBMS transmission on multiple cells;
> Supports semi-static resource allocation e.g. with a time frame of a longcyclic prefix
• Downlink Shared Channel ( DL-SCH )
> Main channel for downlink data transfer. It is used by many logical channels.
> Supports Hybrid ARQ
> Supports dynamic link adaptation by varying the modulation, coding and transmit power
> Optionally supports broadcast in the entire cell;
> Optionally supports beam forming
> Supports both dynamic and semi-static resource allocation
> Supports UE discontinuous reception (DRX) to enable UE power saving
> Supports MBMS transmission
LTE Downlink Transport Channel Con’t
LTE Downlink Physical Channel
• Physical Downlink Shared Channel ( PDSCH)
> This channel is used for unicast and paging functions
> Carries the DL-SCH and PCH
> QPSK, 16-QAM, and 64-QAM Modulation
• Physical Downlink Control Channel ( PCSCH)> Informs the UE about the resource allocation of PCH and DL-SCH,
and Hybrid ARQ information related to DL-SCH
> Carries the uplink scheduling grant
> QPSK Modulation
Uplink Physical Channels
• Physical HARQ Indicator Channel (PHICH)
> Used to report the Hybrid ARQ status
> Carries Hybrid ARQ ACK/NAKs in response to uplink transmissions.
> QPSK Modulation
• Physical Braodcast Channel (PBCH)
> This physical channel carries system information for UEs
requiring to access the network.
> QPSK Modulation
LTE Uplink Channels
Uplink Physical Channels
• Physical Radio Access Channel ( PRACH)> for random access functions
• Physical Uplink Shared Channel ( PUSCH)> Carries the UL-SCH> QPSK, 16-QAM, and 64-QAM Modulation
• Packet Uplink Control Channel ( PUCCH)
> Sends Hybrid ARQ ACK/NAKs
> Carries Scheduling Request (SR)> Carries CQI reports> BPSK and QPSK Modulation
Uplink Transport Channels
• Random Access Channel (RACH)
> Channel carries minimal information
> Transmissions on the channel may be loss due to collisons
• Uplink Shared Channel ( UL–SCH )
> Optional support for beam forming
> Support HARQ
Uplink Logical Channels
• Common Control Channel ( CCCH)> Channel for transmitting control information between Ue and
network.> This channel is used for UEs having no RRC connection with the
network.
• Dedicated Control Channel ( DCCH)> A point-to-point bi-directional channel that transmits dedicated control
information between a UE and the network.> Used by UEs having an RRC connection.
• Dedicated Traffic Channel ( DTCH)
> A point-to-point channel, dedicated to one UE, for the transfer of userinformation.
> A DTCH can exist in both uplink and downlink.
LTE FRAME STRUCTUR> Functions
System can maintain synchronization and manage the different type of information that need to be carried between the eNodeB and UE
> LTE frame structure consist of 1. FDD ( Frequency division duplex)2. TDD ( Time division duplex )
> A radio frame has duration of 10 ms> A resource block spans 12 subcarriers over a slot duration of 0.5 ms> BW RB = 180 KHz> BW Subcarrier = 15 kHz
FDD Frame structure
TDD Frame Structure
DwPTS : Downlink Pilot Time SlotGP : Guard PeriodUpPTS : Uplink Pilot Time Slot.
LTE TDD Sub Frame Allocations
D : sub frame for downlink transmissionS :"special" sub frame used for a guard timeU : sub frame for uplink transmission
Planning Coverage
Downlink Link Budget LTE Unit Value Info
Data Rate kbps 1000
Transmitter - eNodeBa. Tx Power dBm 46 a
b. Tx Antenna Gain dB 18 b
c. Loss System dB 3 cd. EIRP dBm 61 a+b+c
Receiver - UE
e. Ue Noise Figure dB 7 ef. Thermal Noise dBm -102.7 k*T*B
g. SINR dB -5 g
h. Receiver Sensitivity dBm -100.7 e+f+gi. Interference Margin dB 3 i
j. Control Channel Overhead dB 1 j
k. Rx antenna gain dBi 0 kl. Body Loss dB 0 l
MAPL dB 157.7 d-h-i-j+k-l
MAPL Calculation
Propagation Model• LTE – 700 MHz
– Okumura-Hatta
• LTE – 2100 MHz
– Cost 231-Hatta
• LTE – 2600 MHz
– SUI
MTRTcp C)logd6,55logh(44,9)a(hlogh13,82)(logf33,946,3L
(d/100) log 47.9 109.78 Lp
d log hB] log 6,55– [44,9 CH - hB log 13,82– f log 26,16 69,55 Lp
Pathloss SUI
Lp = 109.78 + 47.9 log (d/100)
78.109)100/log(9.47 Lpd
9.47/)78.109()100/log( Lpd9.47/)78.109(10)100/( Lpd
9.47/)78.109(10100 Lpxd9.47/)78.1097.157(10100 xd
00042.110100xd
966.1000d meters
Radius Calculation
L = 2,6 d2
L = 1,95 . 2,6 . d2
L = 1,3 . 2,6 . d2
Radius Calculation
L = 2,6 d2L = 1,95 . 2,6 . d2
2(1) x 2.6 L
2.6 L
2(1) x 2.6 x 1.95 L
5.07 L 2km 2km
For Omni directional For trisectoral
Number of eNodeB
• Urban Area (Trisector)
– total area 242.928
–
–
2km
07.5/928.242eNodeBN
48eNodeBN
PLANNING CAPACITY
Calculation steps:
1. Number of user
2. User density
3. Services and Type
4. Penetration : building, vehicular, pedestrian
5. BHCA and call duration
6. OBQ
7. Site calculation
Number of User
Where:
• Un : num of user on year ‘n’• Uo : initial num of user (based on urban/sub-urban)• a : percent of cellular user (%)• b : penetration of operator A (%)• d : Percent of LTE user • N : num of civilian in the object area• gf : num of user growth factor• n : planned year• u/sub : urban or sub-urban penetration (%)
Uo is Uou or UosubUosub = sub x UoN
Uou = u x UoN
Un = Uo (1 + gf)n
UoN = a x b x d x N
Customer Prediction ParameterEx :
• Population = 1445892 people
• Cellular penetration = assumption 80%
• LTE penetration = assumption 10 %
• LTE provider A penetration = assumption 50 %
User prediction in 5th years
• U5 = 57835 ( 1 + 0.05 )5 assumption fp=5%
= 73814 user
Population 1445892 people
Customer cellular (80%) 1156713 user
Customer LTE (10%) 115671 user
Customer LTE provider A (50%) 57835 user
Example User Calculation
Ex :• urban penetration = assumption 60 %
• suburban penetration = assumption 40 %
• Urban user = 73814 x 60 % = 44288 user
• Suburban user = 73814 x 40 % = 29525 user
User Density
• Lu : urban area wide
• Lsub : sub-urban area wide
• L : object area wide
• Cu : Urban area density
• Csub : sub-urban area density
Lu = L x u Lsub = L x sub
Cu = Un/ Lu Csub = Un/Lsub
Example User Density Calculation
Ex :• urban area penetration = assumption 40 %
• suburban area penetration = assumption 40 %
• Openarea = assumption 20 %=>
Urban area wide (Lu) : 242,928 km2
Sub-urban area wide (Lsub) : 242,928 km2
=>Cu = 44288 / 242,928 = 182,31232 user/km2
Csub = 29525 / 242,928 = 121,54155 user/km2
Services and Type
• Services (Rb)– VoIP : 64 kbps
– FTP : 1000 kbps
– Video : 384 kbps
• Type (c)– Building : 50 %
– Vehicular : 30 %
– Pedestrian : 20 %
• Penetration (p) per type per servicee.g: BUILDING VoIP usage penetration = 0.5
BUILDING FTP usage penetration = 0.4PEDESTRIAN Video usage penetration = 0.3
• BHCA (B) per type per servicee.g: BUILDING VoIP usage penetration = 0.008
BUILDING FTP usage penetration = 0.009PEDESTRIAN Video usage penetration = 0.008
• Call duration (h) per type per service (ms)e.g: BUILDING VoIP usage penetration = 60
BUILDING FTP usage penetration = 50PEDESTRIAN Video usage penetration = 50
service net user bit rate (Rb)
VoIP 64000
FTP 1000000
Video 384000
typecall duration (h)
voip video ftp
building 60 40 50
pedestrian 60 50 70
vehicular 60 40 80
BHCA (B)
Service Building Pedestrian Vehicular
Voip 0,008 0,008 0,009
Video 0,007 0,008 0,009
FTP 0,009 0,008 0,008
Penetrasi User (p)
Building Pedestrian Vehicular
Voip 0,5 0,5 0,2
Video 0,3 0,3 0,2
FTP 0,4 0,4 0,3
OBQ (Offered Bit Quantity)• VoIP
OBQT = cT x Cu; T x pT x RbVoIP x BT x hT
• FTP OBQT = cT x Cu; T x pT x RbFTP x BT x hT
• VideoOBQT = cT x Cu; T x pT x RbVid x BT x hT
Note: if T= pedestrian, then “OBQT “ is pedestrian OBQ, “BT “ is pedestrian BHCA, etc.
T : Type (Building; Vehicular; Pedestrian)
OBQ cont’d
Where:
OBQVoIP = OBQvehicular + OBQbuilding + OBQ pedestrian
OBQFTP = OBQvehicular + OBQbuilding + OBQ pedestrian
OBQVideo = OBQvehicular + OBQbuilding + OBQ pedestrian
OBQ total = OBQVoIP + OBQFTP + OBQVideo
OBQtotal= 20,74860049 + 13,97825 + 8,260936 = 42,98779
OBQ
Service Building Pedestrian Vehicular
Voip 1,400158616 0,5600634 0,252029
Video 2,940333094 5,2505948 1,008114
FTP 16,40810878 8,1675919 7,000793
∑ 20,74860049 13,97825 8,260936
OBQ cont’d
eNodeB Capacity
ms
NxxN
Hz
bitMbpsePeakBitRat
subframepersymbol
ssubcarrier1
][
Bandwidth (MHz)Modulation
QPSK 16 QAM 64 QAM
1.4 2.016 Mbps 4.032 Mbps 6.048 Mbps
3 5.04 Mbps 10.08 Mbps 15.12 Mbps
5 8.4 Mbps 16.8 Mbps 25.2 Mbps
10 16.8 Mbps 33.6 Mbps 50.4 Mbps
15 25.2 Mbps 50.4 Mbps 75.6 Mbps
20 33.6 Mbps 67.2 Mbps 100.8 Mbps
Site Calculation• Site (L)
L = (50.4 x 3) / OBQtotal
= (50.4 x 3) / 42,98779 = 3,5172778 km2
• Radius (d)
d = (L / 2.6 / 1.95) ^ 0.5
= (3,5172778 / 2.6 / 1.95) ^ 0.5 = 0,832912489 km
50.4 Mbps ---> (asumption: using 64 QAM 1/1, BW = 10 MHz)
Site Calculation Con’t
• Number of eNodeB (M)
M = Lu / L
= 242,928 km2 / 3,5172778 km2
= 69,06704366
We use “Lu” JUST IN CASE we count urban capacity only
LTE Simulation Using Atoll
Getting Started with Atoll
New -> From a
Document
Template
Choose LTE
workspace
Setting Project Area
It is used to display the project area from the map raster.
To set the coordinate type and the area displayed on the worksheet.
Import Raster Map
raster is a contour map based on the topography of the area. Raster consist of clutter map, height map and vector map
Import Raster Map Con’t
Clutter index -> Clutter Classes
Height index ->Altitude
Vector index ->Vectors
Frequency Band
frequency bands and can beseen in the LTE specification3GPP.org
Antenna Polarization Model
add the appropriate antenna used
Antenna Polarization Model
Setting Feeder
To setting feeder & connector loss at eNode B equipment
Setting Transmitter Frequency Bandafter determining the frequency band, set the transmitter frequency as the frequency and morpho class used
Setting Transmitter Frequency Band Con’t
EnvirontmentDelete user
Delete environtment
Delete User ProfileDelete service thensetting service type
ServicesDelete service then setting service type Edit Service
Service
VoIP Video FTP
Add User Profile
Assumption throughput user = 50 kbps
Add User Profile
Pedestrian
Vehicular
Add Environtment
Plotting eNode B
eNode B can be in place based on planning calculation or the use of existing nodeB or BTS
Make a Prediction
make predictions based on measured
fill of the receiver sensitivity specification
Click calculate
Coverage by Signal Level
Result Histogram and CDF Chart
Reference
[1] Abdul Basit, Syed. Dimensioning of LTE Network Description ofModels and Tool, Coverage and Capacity Estimation of 3GPPLong Term Evolution radio interface. 2009.
[2] Coverage and Capacity Dimensioning Recommendation:Ericsson. 2009.
[3] Holma, Harri and Antti Toskala. WCDMA for UMTS – HSPAEvolution and LTE. John Willey and Son: 2007.
[4] 3GGP. TS 36.XXX “LTE TS Group Series”. 2009.