Atoll_3.3.0_LTE
description
Transcript of Atoll_3.3.0_LTE
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Forsk 2015 Confidential Do not share without prior permission
LTE Features Atoll 3.3.0
Slide 1
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1. LTE Concepts
2. LTE Planning Overview
3. Modelling a LTE Network
4. LTE Predictions
5. Neighbours Allocation
6. Automatic Resource Allocation
7. MIMO Features
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Training Programme
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1. LTE Concepts
Overview
OFDM Definition
Advanced OFDM: OFDMA
Benefits of OFDM/OFDMA
Multiple Access Techniques and Duplexing Methods
LTE Radio Interface
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What is 4G?
Evolution of 3GPP standards
Release 99: UMTS FDD (3G)
Release 4: UMTS TDD + FDD repeaters (3G)
Release 5: HSDPA (3.5G)
Release 6: HSUPA (enhanced uplink) + MBMS (3.5G)
Release 7: HSPA+ (2x2 MIMO, higher order modulations, etc.) (3.75G)
Release 8: LTE FDD and TDD (3.9G) + HSPA+ multi-carrier
Release 10: LTE advanced (4G)
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Technologies
3GPP Release
5/6 3GPP Release 99/4
3GPP Release
7/8
LTE 3GPP Release 8
LTE Adv. 3GPP
Release 10
WCDMA 384 kbps downlink
128 kbps uplink
HSDPA/HSUPA 14 Mbps peak downlink
5.7 Mbps peak uplink
HSPA+ 42,2 Mbps peak downlink
11 Mbps peak uplink
LTE 100 Mbps peak downlink
50 Mbps peak uplink
LTE Adv. 100 Mbps to 1Gbps
peak downlink
WCDMA WCDMA + Enhanced architecture
+ Higher order modulations
WCDMA + MIMO
+ Dual-carrier
OFDMA SC-FDMA
MIMO
+ Carrier aggregation (DL/UL) + HetNets
+ enhanced MIMO (8*8)
Slide 4
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OFDM Frequency and Time Domains
What is OFDM ?
OFDM = Orthogonal Frequency Division Multiplexing
Frequency domain organization
Advanced form of Frequency Division Multiplexing (FDM)
Principle:
Wideband channel split into multiple orthogonal narrowband radio carriers (subcarriers)
Subcarriers are spaced in a manner that the centre of each subcarrier corresponds to a zero crossing point of the neighbouring subcarriers
Good spectral efficiency compared to FDM systems
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OFDM Frequency and Time Domains
Time domain organization
Adjustable guard period referred to as cyclic prefix
Used to fight against multipath effects (delay spread)
Two configurations depending on the environment
Normal cyclic prefix: 4.7 us
Extended cyclic prefix: 16.7 us
Typical values of delay spread:
Open environment: 0.2 us
Suburban: 0.5 us
Urban: 3 us
Hilly area: 3-10 us
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Advanced OFDM: OFDMA
OFDM : Orthogonal Frequency Division Multiplexing
OFDM allocates users in time domain only
The entire channel bandwidth is allocated to one user
OFDMA : Orthogonal Frequency Division Multiple Access
OFDMA allocates users in time and frequency domains
Several users served at once
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Reso
urc
e B
loc
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Benefits of OFDM/OFDMA
OFDM(A) summary:
No ICI and ISI:
No intra-cell interference in theory
Possibility to support less robust modulations like 16QAM, 64QAM for higher throughput !
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Narrowband orthogonal subcarriers
Negligible inter-carrier interference (ICI)
No frequency selective fading
Long symbol durations + cyclic prefix
Negligible inter-symbol interference (ISI)
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Multiple Access Techniques and Duplexing Methods
OFDMA in DL
Each subcarrier carries one specific data symbol (QPSK, 16QAM...)
SC-FDMA in UL (OFDMA variant)
Single-Carrier Frequency Division Multiple Access
Each subcarrier carries information of all data symbols
Technique well suited to LTE UL requirements
Lower PAPR*
Power consumption limited
LTE can be deployed in FDD and TDD
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*PAPR: Peak to Average Power Ratio
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LTE Radio Interface
LTE channel structure
A channel is composed of more than 1 frequency block (FB)
Fixed width = 180 kHz (LTE system level constant)
1 frequency block over 1 slot = 1 resource block (RB)
Each FB is composed of many subcarriers
Two subcarrier widths possible: 15 kHz, 7.5 kHz (specified for MBMS/SFN services)
1 FB = 12 SCa of 15 kHz OR 24 SCa of 7.5 kHz
1 subcarrier over 1 SD (symbol duration) = 1 resource element (RE)
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LTE PHY layer supports a wide range of bandwidths
Spectrum flexibility
LTE Channel Structure
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Channel bandwidth
Subcarrier spacing
Number of FBs
Number of subcarriers
Sampling frequency
FFT size
1.4 MHz
15 kHz
(7.5 kHz for MBMS)
6 72 1.92 MHz
(1/2 x 3.84) 128
3 MHz 15 180 3.84 MHz (1 x 3.84)
256
5 MHz 25 300 7.68 MHz (2 x 3.84)
512
10 MHz 50 600 15.36 MHz (4 x 3.84)
1024
15 MHz 75 900 23.04 MHz (6 x 3.84)
1536
20 MHz 100 1200 30.72 MHz (8 x 3.84)
2048
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LTE Frame Structure
Time domain structure (for both UL and DL)
Specific frame structures for TDD and FDD
1 frame = 10 ms = 2 half-frames (TDD) = 10 sub-frames or TTI (each 1 ms) = 20 slots (each 0.5 ms)
1 slot (0.5 ms) = 6 or 7 symbol durations (depending on the cyclic prefix duration)
1 FB over 1 sub-frame (1ms) = smallest unit that can be allocated by the scheduler (scheduling block)
Control channels transmitted on sub-frames 0 and 5 (always DL)
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LTE Frame
10 ms
SF 0 SF 1 SF 9 ..
1 ms
Slot 0 Slot 1 Slot 2 Slot 3 Slot 18 .. Slot 19
0.5 ms
OFDM Symbol 0 C
P OFDM
Symbol 1 CP
OFDM Symbol 3 C
P OFDM
Symbol 4 CP
OFDM Symbol 5 C
P OFDM
Symbol 6 CP
OFDM Symbol 2 C
P
Slide 12
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eNode-B
Physical Channels
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HARQ feedback,
CQI reporting,
UL scheduling request,
CQI reporting for MIMO related feedback
Random access
Traffic
Pilot (channel estimation),
slot/frame synchronization and
cell identification
Traffic, MBMS,
system information,
paging
HARQ feedback,
transport format,
UL scheduling grants,
DL resource allocation
Slide 13
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OFDMA LTE Frame (DL)
Structure of a resource block
Frame structure of type I (FDD), 1 antenna port, F = 15 kHz
Standard frequency block:
Any frequency block within the centre 6 frequency blocks:
Legend:
Downlink reference signals
PBCH (Physical Broadcast Channel)
PSS (Primary Synchronisation Signal)
SSS (Secondary Synchronisation Signal)
PDCCH / PHICH / PCFICH (Physical - Downlink Control / HARQ Indicator / Control Format Indicator - Channels)
PDSCH (Physical Downlink Shared Data Channel)
RBs allocated to mobiles are not necessarily adjacent interference coordination
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OFDMA LTE Frame (DL)
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OFDM symbol 0 C
P OFDM
symbol 1 CP
OFDM symbol 3 C
P OFDM
symbol 4 CP
OFDM symbol 5 C
P OFDM
symbol 6 CP
OFDM symbol 2 C
P
Legend:
Downlink reference signals
PBCH
PSS
SSS
PDCCH / PHICH / PCFICH
PDSCH
1 subframe = 2 slots (1 ms)
1 frame (10 ms) = 10 subframes (1 ms) = 20 slots (0.5 ms)
SF 0 SF 1 SF 2 SF 3 SF 4 SF 5 SF 6 SF 7 SF 8 SF 9
7 OFDM symbols at normal CP per slot (0.5 ms)
0 1 2 3 4 5 6 0 1 2 3 4 5 6
Cen
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6 R
Bs
180 kHz
Ch
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Slide 15
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SC-FDMA LTE Frame (UL)
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Legend:
UL DRS (Uplink Demodulation Reference Signal)
UL SRS (Uplink Sounding Reference Signal)
PUCCH (Physical Uplink Control Channel) (incl. HARQ feedback and CQI reporting)
Demodulation Reference Signal for PUCCH
PUSCH (Physical Uplink Shared Channel)
1 subframe = 2 slots (1 ms)
SF 0 SF 1 SF 2 SF 3 SF 4 SF 5 SF 6 SF 7 SF 8 SF 9
0 1 2 3 4 5 6 0 1 2 3 4 5 6
1 frame (10 ms) = 10 subframes (1 ms) = 20 slots (0.5 ms)
180 kHz
Ch
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Slide 16
OFDM symbol 0 C
P OFDM
symbol 1 CP
OFDM symbol 3 C
P OFDM
symbol 4 CP
OFDM symbol 5 C
P OFDM
symbol 6 CP
OFDM symbol 2 C
P
7 OFDM symbols at normal CP per slot (0.5 ms)
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1. LTE Concepts
2. LTE Planning Overview
3. Modelling a LTE Network
4. LTE Predictions
5. Neighbours Allocation
6. Automatic Resource Allocation
7. MIMO Features
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Training Programme
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2. LTE Planning Overview
LTE Features Supported in Atoll
LTE Planning Workflow in Atoll
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LTE Features Supported in Atoll
Atoll fully supports LTE/LTE-A networks
Various E-UTRA frequency bands
Scalable channel bandwidths (from 1,4 MHz to 20 MHz)
Support of TDD and FDD frame structures
Normal and extended cyclic prefixes
Downlink and uplink control channels and overheads
Downlink and uplink reference signals, PSS, SSS, PBCH, PDCCH, PUCCH, etc.
Physical Cell IDs implementation
Network capacity analysis using Monte-Carlo simulations
RSRP, RSSI and RSRQ support in predictions and simulations
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LTE Features Supported in Atoll
Atoll fully supports LTE/LTE-A networks
Inter-cell interference coordination (ICIC) support
Hard FFR (Fractional Frequency Reuse),
Time-switched FFR,
Soft FFR,
Partial soft FFR
eICIC (enhanced ICIC)
Support of fractional power control (UL)
Modelling of multi-layer heterogeneous networks (HetNets)
Small Cells, Relay nodes
Layers and eICIC features
Services can be mapped to QoS Class Identifiers (QCI)
Beamforming modelling (smart antennas)
Possibility of fixed subscriber database for fixed applications
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Atoll fully supports LTE/LTE-A networks
Carrier Aggregation up to 5 carriers of 20 MHz
Dynamic Multiple Input Multiple Output (MIMO) systems
Transmit and receive diversity
Single-user MIMO or spatial multiplexing
Dynamic MIMO switching
Modelling of Multi-User MIMO (MU-MIMO)
AAS (Active Antenna Systems) with beamforming
Tools for automatic resource allocation
Automatic allocation of neighbours
Automatic allocation of Physical Cell IDs (PCI)
Automatic allocation of frequencies
PRACH RSI (root sequence indexes)
Network verification using drive test data
Specific module (AFP)
LTE Features Supported in Atoll
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LTE Planning Workflow in Atoll
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Open an existing project or create a new one
Prediction study reports
Traffic maps
Network configuration - Add network elements
- Change parameters
User-defined values
Automatic or manual neighbour allocation
Basic predictions (Best server, signal level)
Monte-Carlo simulations
Signal quality and throughput predictions
Cell load conditions
Subscriber lists
And/or
Frequency plan analysis
Automatic or manual frequency planning
Automatic or manual Physical Cell ID and PRACH Root Sequence Index planning
ACP
Slide 22
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1. LTE Concepts
2. LTE Planning Overview
3. Modelling a LTE Network
4. LTE Predictions
5. Neighbours Allocation
6. Automatic Resource Allocation
7. MIMO Features
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Training Programme
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3. Modelling a LTE Network
Global Settings
Frequency bands and channels definition
Global LTE frame definition
Radio Parameters
Sites
Transmitters
Cells
Multi-layer Networks (HetNets)
HetNets Configuration
eICIC
Relay links
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Global Settings (1/2)
Frequency bands and channels definition
Atoll can model multi-band networks within the same document
2 duplexing methods available: FDD and TDD
Bandwidths from 1,4 MHz to 20 MHz supported
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Global LTE frame definition
System-level constants (hard-coded)
Width of a resource block (180 kHz)
Frame duration (10 ms)
Other control channel overheads defined by 3GPP
Reference signals, PSS, SSS, PBCH, etc.
Global Settings (2/2)
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TDD option only: Special subframe
selection
Number of SD for PDCCH (from 0 to 4) carrying DL
and UL resource allocation information
Normal (default) or extended cyclic prefix at 15 kHz, 7 SD/slot (normal), or 6 SD/slot (extended)
Average number of resource blocks for
PUCCH
Slide 26
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Advanced Settings (1/2)
Downlink Cell-specific Reference Signals
Reference Signal Power Boost
With more than one antenna port
Each antenna uses different resource elements to transmit reference signals
Resource elements of one antenna port that correspond to reference signal transmission on another antenna port are not used (DTX)
Different LTE equipment and vendors may support different methods for reusing the energy corresponding to the unused resource elements
0l
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even-numbered slots odd-numbered slots
Antenna port 0
even-numbered slots odd-numbered slots
Antenna port 1
even-numbered slots odd-numbered slots
Antenna port 2
even-numbered slots odd-numbered slots
Antenna port 3
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Advanced Settings (2/2)
Downlink Transmit power calculation
0-Max Power defined manually in the cell table. The energy of the unused resource elements is distributed on the downlink channels.
1-RS EPRE defined manually. The Max Power will automatically be calculated
2-Max Power defined manually in the cell table. The energy of the unused resource elements is allotted to reference signal resource elements only (RS Power Boost = 3dB for 2 antennas and 6dB for 4 antennas)
3-Max Power defined manually in the cell table. The energy of the unused resource elements is lost
4-Max power and RS EPRE defined manually in the cell table.
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Radio Parameters Overview
Sites
Characterized by their X (longitude) and Y (latitude) coordinates
Transmitters
Activity
Antenna configuration (model, height, azimuth, mechanical/electrical tilts...)
UL and DL losses / UL noise figure
Propagation (model, radius and resolution)
Cells
Frequency band & channel
Layer
Cell Type
Physical Cell ID
Power definition of DL channels
Min. RSRP
DL and UL traffic loads
Diversity support (MIMO)
Neighbours
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Presented in the General Features course
Slide 29
Specific parameters for LTE technology
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Transmitter Parameters
Transmitter parameters
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Propagation settings Antenna configuration and losses parameters
Antenna configuration
DL and UL total losses,
UL noise figure
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Cell Parameters
Main parameters
Cell activity
Only active cells are considered in predictions
Frequency band and channel number
Physical Cell ID
PSS/SSS ID automatically computed
Powers and energy offsets
Computed from RS EPRE*
Min. RSRP
Used as a cell coverage limit
Load conditions
DL traffic load (%)
UL noise rise due to surrounding mobiles (dB)
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*RS EPRE: Reference Signal Energy Per Resource Element
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Cell Parameters
Main parameters
Automatic resource allocation parameters
Allocation status
Channels
Physical Cell ID
PRACH RSI
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Cell Parameters
Main parameters
Layer
Similar to HCS layers in 2G networks and layers in 3G
Used to model HetNets*
Frame configuration (optional)
See next slide
MIMO configuration
Diversity support DL/UL:
Transmit diversity
SU-MIMO
AAS: Advanced Antenna Systems
MU-MIMO
Neighbours-related parameters
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*HetNets: Heterogeneous Networks
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Cell Parameters
Specific frame configurations
Each cell can be assigned a specific frame configuration (optional)
PDCCH/PUCCH overheads and cyclic prefix can be set for each frame
Override values defined in global parameters
PRACH preamble format
Defines a max. distance limiting the best server coverage (see 3GPP specs.)
Specific parameters used in case of interference coordination support (ICIC)
Group 0/1/2 frequency blocks, ICIC mode, cell-edge power boost (DL)
TDD parameter: Special Subframe Configuration
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Multi-layer Networks (HetNets)
What is HetNets?
HetNets, or Heterogeneous Networks, are comprised of traditional large macrocells and smaller cells like:
Microcells (< 5W)
Picocells (< 1W)
Femtocells (~ 200mW)
HetNets provide two basic benefits to operators:
Increase capacity in hotspots as traffic is not uniformly distributed
Improve coverage in places where macro coverage is not adequate
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Multi-layer Networks (HetNets)
Heterogeneous network deployment
Atoll LTE fully supports multi-layer networks
Different layers with different priorities
Taken into account to determine the best serving cell ( they are not used in simulation)
The definition of layers can be based on the operating frequencies
Each cell has to be mapped to a layer
You can also assign supported layers to different services and terminals
Layers management
You can define network layers with corresponding:
Priorities
Supported mobile speeds
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Multi-layer Networks (HetNets)
Layers management
Principle of the cell selection margins
Due to the wide difference of power levels between macro and pico/femtocells, most of the UEs will get associated to the macrocells resulting in a load imbalance throughout the network
To counterbalance this effect, and thus enhance the system performance, an offset is to be added to the actual RSRP value from the pico/femtocells (range expansion) during the cell selection process
Cell range expansion concept modelled by cell selection margins in Atoll
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Area where the picocell is received with a higher power than the macrocell
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The Handover Margin is used for selecting the best server and for avoiding the ping-pong effect* between cells.
Multi-layer Networks (HetNets)
Can be defined in the transmitter properties dialogue
Cell Layer parameter [Cells tab]
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The CIO is used in order to rank the potential servers for best serving cell selection in connected mode
Cell Selection Threshold (CST) is used to adjust the Min RSRP threshold of cells belonging to different priority layers
Handover ping-pong*: base stations bounce the link with the mobile back and forth between cells.
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Multi-layer Networks (HetNets)
Compatibility between services, terminals and network layers
Managed in the services and terminals properties
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Best Server Identification
Best Server determination
(1) Filter the potentials serving cells based on
Cell, service and terminal compatibility with the selected layer
Layers maximum speed Mobility Types speed (Layers table and Mobility Type table)
UECell distance PRACH maximum cell range
RSRP > min RSRP (Cell table)
(2) Identify the initial serving cell
On each pixel, Atoll selects the serving cells corresponding to the highest priority layer
Atoll verifies if these servers respect a RSRP level > min RSRP + Cell Selection threshold
If they do, the server with the maximum RSRP level will be considered as initial serving cell
(3) Atoll calculates the best server criterion (BSc) for the initial serving cell and the other potential serving cells
Initial serving cell: BSc = RSRP + Handover Margin + CIO
Other serving cells: BSc = RSRP + CIO
(4) The server with the highest best server criterion (BSc) will be considered as best server (for all potential serving cells from all layers)
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Best Server Identification
Use case : 1 Macro site 800 MHz + 2 Micro sites 1800 MHz + 6 Small Cells 2600 MHz
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Cell Table
Mobility Types
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Cell TypeRSRP Level
(dBm)Distance (m) Layer
Layer Max
Speed
Small 3 -114 88 Small Cell 2600 50
Macro 2 -106 1860 Macro 800 120
Micro 2_3 -108 744 Micro 1800 50
Micro 2_2 -110 744 Micro 1800 50
Small 4 -118,5 118 Small Cell 2600 50
Micro 2_1 -122 744 Micro 1800 50
Best Server Identification
Step 1 : Atoll filters potential serving cells
Use case inputs:
In Cells Table, minimum RSRP = -120 dBm
For Pedestrian Mobility Type, average speed 3 km/h
High Speed Internet Service: All layers allowed
MIMO Terminal: All layers allowed
Default configuration for frame configuration => PRACH format 0 (max distance 14521 m)
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Potential serving cells respecting conditions
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Cell TypeRSRP Level
(dBm)
Cell Selection
Threshold
Minimum
level targetedLayer
Layer Priority
(Lowest 0)
Small 3 -114 2 -118 Small Cell 2600 2
Macro 2 -106 0 -120 Macro 800 0
Micro 2_3 -108 0 -120 Micro 1800 1
Micro 2_2 -110 0 -120 Micro 1800 1
Small 4 -118,5 2 -118 Small Cell 2600 2
Step 2 : Identify the initial serving cell
Atoll selects the serving cells corresponding to the highest priority layer from the potential serving cells and verifies if these servers respect a RSRP level > min RSRP + Cell Selection threshold
If the servers respect this minimum condition, Atoll selects the server with the highest RSRP level and consider it as the initial serving cell
The Small Cell 3 is the initial serving cell in this use case
Best Server Identification
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Highest priority layer selection
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Cell TypeRSRP Level
(dBm)
Handover
Margin (dB)
Cell Individual
offset (dB)
BSc
(dB)
Small 3 -114 4 4 -106
Macro 2 -106 0 0 -106
Micro 2_3 -108 2 1 -107
Micro 2_2 -110 2 1 -109
Small 4 -118,5 4 4 -114,5
Step 3 : Atoll calculates the best server criterion (BSC) for the initial serving cell and the other potential serving cells
Best serving cell candidate: BSC = RSRP + Handover Margin + CIO
Other serving cells: BSC = RSRP + CIO
Best Server Identification
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Handover Margin applied for the cell candidate only
CIO applied for all serving cells.
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Step 4: Atoll considers the cell with the highest BSc as the best server: Small Cell 3
Best Server Identification
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The serving cell with the highest RSRP level is not necessarily the best server. The selection is based on the BSc calculation.
MACRO 900
MICRO 2100
Small cell range expansion: The Small cell maintains connection with the UE outside its best server area. The expansion is impacted by the CIO and the Handover Margin.
MACRO 900
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Range expansion analysis: LTE specific predictions are impacted by the new best server algorithm
Impact on a Effective Signal Analysis displaying the RSRP level per best server area
The handover margin and the CIO impact the RSRP level shown per pixel. The best server area is changed so the RSRP level is automatically changed
Best Server Identification
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RSRP level without considering layers RSRP level considering layers
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Best Server Identification
Best server selection new algorithm
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Potential serving cells based on
Service/Terminal compatibility
Minimum RSRP level Mobility type vs layer max speed
PRACH max cell range
Rank the different servers
based on
Layers priority Maximum level considering CST*
Atoll analyses the Cell
Individual Offset and Handover
Margin
Best Server identified
CTS*: Cell Selection Threshold
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Carrier Aggregation (LTE-A)
Definition
Carrier Aggregation (CA) increases the channel bandwidth by combining multiple RF carriers
Each individual RF carrier is known as a Component Carrier (CC)
All CCs belong to the same eNodeB
5 CCs may be aggregated to reach a maximum of 100 MHz
However, initial LTE-A deployments will likely be limited to 2 CCs
Carrier Aggregation is applicable to both DL and UL, and both FDD and TDD
3 general types of Carrier Aggregation scenario have been defined by 3GPP
Intra-band contiguous
Intra-band non-contiguous
Inter-band
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Carrier Aggregation (LTE-A)
Carrier Aggregation categorises cells as:
Primary Cell
The cell upon which the UE performs initial connection establishment
Each connection has a single primary cell
The primary cell can be changed during the handover procedure
Used to generate inputs during security procedures
Used to define NAS mobility information (e.g. Tracking Area Identity)
Secondary Cell
A cell which has been configured to provide additional radio resources after connection establishment
Each connection can have multiple secondary cells
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Serving Cell
Both primary and secondary cells are categorised as serving cells
There is one HARQ entity per serving cell at the UE
The different serving cells may have different coverage
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Carrier Aggregation (LTE-A)
Primary and Secondary cells are modelled in Atoll via the parameter Cell Type
Defines whether the cell supports LTE (3GPP Rel-8/9) and/or LTEA (3GPP Rel-10 and later)
A cell can be configured to be a LTE cell, a LTEA P-Cell (Primary Cell), and a LTEA S-Cell (Secondary Cell)
If the cell type is left empty, Atoll considers it as LTEonly
Both LTE and LTEA users can connect to LTEonly cells without the possibility to perform Carrier Aggregation
Cells that only support LTEA, and not LTE, can only serve LTEA users
The process of only allowing LTEA users to connect to a cell and excluding all LTE users is called Cell Barring
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Carrier Aggregation (LTE-A)
UE Categories in Atoll
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Specific UE Categories
LTE-A to LTE Downgrade Category: Used to define the UE category to consider when a LTE-A mobile is connected to a LTE Rel-8/9 cell
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Carrier Aggregation (LTE-A)
LTE-A terminals in Atoll
Carrier Aggregation support is defined at the terminal level
You have to define the maximum number of Secondary Cells supported in DL and UL
The number of UL Secondary Cells must be less than or equal to the number of DL Secondary Cells
Setting the maximum number of Secondary Cells to 0 means that the terminal does not support Carrier Aggregation
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Carrier Aggregation (LTE-A)
Services in Atoll
Define whether a service can manage carrier aggregation or not
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Carrier Aggregation (LTE-A)
Improvements in predictions for Carrier Aggregation
You can carry out coverage predictions for different serving cells
Main (P-Cell or LTE Rel-8/9 cells)
Nth S-Cell
You can also perform aggregated throughput predictions including all serving cells, or even some of them
Forsk 2015 Slide 54 Confidential Do not share without prior permission
Throughput prediction Coverage prediction
-
Carrier Aggregation (LTE-A)
Example: Coverage by throughput
Intra-band contiguous Carrier Aggregation
Co-located cells with similar coverage
Channel width = 20 + 20 MHz
MIMO 2 X 2 (TX DIV+SU-MIMO)
Forsk 2015 Slide 55 Confidential Do not share without prior permission
With a LTE Rel-8/9 terminal With a LTE-A terminal
-
Carrier Aggregation (LTE-A)
Improvements in the Point Analysis Tool for Carrier Aggregation
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Aggregated throughput
Serving Cells (P-Cell and S-Cell)
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1. LTE Concepts
2. LTE Planning Overview
3. Modelling a LTE Network
4. LTE Predictions
5. Neighbours Allocation
6. Automatic Resource Allocation
7. MIMO Features
Forsk 2015 Slide 57 Confidential Do not share without prior permission
Training Programme
-
4. LTE Predictions
Introduction
Parameters used in Predictions
Prediction Settings
Fast Link Adaptation Modelling
Coverage Prediction Examples
Point Analysis Studies
Forsk 2015 Confidential Do not share without prior permission Slide 58
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Introduction
Forsk 2015 Confidential Do not share without prior permission Slide 59
RSRP level: Receive Signal Receive Power calculated for one RE RS level: Reference Signal level calculated on the whole bandwidth
Coverage predictions
RSRQ: Reference Signal receive Quality PDSCH C/I+N: Signal-to-interference-plus-noise ratio based on the PDSCH
channel
RS C/I+N: Signal-to-interference-plus-noise ratio based on the Reference Signal channel
Quality predictions
Based on the RLC or Application layers Peak, Effective or Average throughput Carried out for one or several users
Throughput predictions
-
Introduction
Principle of LTE studies based on traffic
Study calculated for:
Given load conditions:
UL noise rise (dB)
DL traffic load (%)
A non-interfering user with:
A service
VoIP,
Web browsing,
FTP download...
A mobility
Fixed,
Pedestrian,
50 Km/h...
A terminal type
Smartphone,
Rooftop terminal...
Forsk 2015 Confidential Do not share without prior permission Slide 60
LTE prediction
UL noise rise
DL traffic load
Service Mobility
Terminal
-
Load Conditions
Load conditions, defined in the cells properties
Traffic load (DL) (%)
UL noise rise (dB)
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Values taken into consideration in predictions for each cell
Slide 61
-
Service Properties
Service: parameters used in predictions
Highest/lowest bearers in UL and DL
Body loss
Application throughput parameters
Forsk 2015 Confidential Do not share without prior permission Slide 62
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Mobility Properties
Mobility: parameters used in predictions
Mapping between mobility and thresholds in bearer and quality indicator determination (as radio conditions depend on user speed)
Forsk 2015 Confidential Do not share without prior permission Slide 63
Reception equipment properties
Mapping
-
Terminal Properties
Terminal: parameters used in predictions
Min/max terminal power
Gain and losses
Noise figure
Antenna settings (incl. MIMO support)
Carrier aggregation settings
Forsk 2015 Confidential Do not share without prior permission Slide 64
Number of antenna ports in UL and DL in case of MIMO support
Min/max terminal power + noise figure + losses
Support of MIMO
Carrier aggregation parameters
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Fast Link Adaptation Modelling
Atoll determines, on each pixel, the highest bearer that each user can obtain
After the layer determination, connection to the best server in terms of RS level or RSRP
Bearer chosen according to the radio conditions (PDSCH and PUSCH CINR levels)
Process: prediction done via look-up tables
Forsk 2015 Confidential Do not share without prior permission Slide 65
RS level (C) or RSRP evaluation
Best server area determination
(limited by min. RSRP)
Radio conditions estimation
(PDSCH and PUSCH CINR calculation)
Bearer selection
Throughput & quality indicator predictions (BER
and BLER)
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Interference Estimation
Atoll calculates PDSCH and PUSCH CINR according to:
The victim traffic (PUSCH or PDSCH) power [C]
The sum of interfering signals [I], affected by:
The interfering signals EIRP (power + gains - losses) weighted by traffic loads (in DL)
The path loss from the interferers to the victim
The shadowing effect and the indoor losses (optional)
The interference reduction factor applied to interfering base stations transmitting on adjacent channels (adjacent channel suppression factor)
The interference reduction due to static ICIC (optional)
Forsk 2015 Confidential Do not share without prior permission Slide 66
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Prediction Examples (General Studies)
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Coverage by transmitter
(based on RSRP levels)
Cell dominance (overlapping zones)
(based on RSRP levels)
Slide 67
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Prediction Examples (Dedicated Studies)
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Coverage by RSRP level
Coverage by RSRP level
(with power boost)
Slide 68
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Application Channel Throughput (UL)
Prediction Examples (Dedicated Studies)
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Coverage by PUSCH CINR
Slide 69
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Point Analysis Tool: Reception
Radio reception diagnosis at a given point
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Choice of UL/DL load conditions: if (cells table) is selected analysis based on DL load and UL
noise rise from cells table
Definition of the user (layer or channel, terminal, service,
mobility) Cell bar graphs (best server on top)
Analysis details on reference signals, PDSCH and PUSCH
Reference signals,
PDSCH and PUSCH
availability (or not)
Selection of the value to be displayed (RS, SS, PDSCH, RSRP)
Slide 70
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Point Analysis Tool: Interference
Radio interference diagnosis at a given point
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Choice of UL/DL load conditions: if (cells table) is selected analysis based on DL load and UL
noise rise from cells table
Definition of the user (layer or channel, terminal, service,
mobility)
Selection of the value to be displayed (RS, SS, PDSCH, RSRP)
Serving cell (C)
Total level of interference
(I + N)
List of interfering cells
Slide 71
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1. LTE Concepts
2. LTE Planning Overview
3. Modelling a LTE Network
4. LTE Predictions
5. Neighbours Allocation
6. Automatic Resource Allocation
7. MIMO Features
Forsk 2015 Slide 72 Confidential Do not share without prior permission
Training Programme
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5. Neighbour Allocation
Detailed information about neighbours allocation is available in Atoll_3.3.0_Neighbours.pdf
Forsk 2015 Confidential Do not share without prior permission Slide 73
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1. LTE Concepts
2. LTE Planning Overview
3. Modelling a LTE Network
4. LTE Predictions
5. Neighbours Allocation
6. Automatic Resource Allocation
7. MIMO Features
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Training Programme
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6. Automatic Resource Allocation
Automatic Physical Cell ID planning
AFP overview
Automatic resource allocation process
Interference matrix calculation
Physical Cell ID overview
PCI allocation process
Running the automatic resource allocation
PCI allocation examples
Automatic frequency planning
Running the automatic resource allocation
Frequency allocation examples
Automatic PRACH Root Sequences
PRACH channel
PRACH RSI Planning Theory
Automatic PRACH RSI Planning
Forsk 2015 Confidential Do not share without prior permission Slide 75
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AFP Overview (1/2)
Prerequisite: AFP license
Goal: Optimize resource allocation (channels, PCI or PRACH RSIs) following the user-defined constraints
To minimize interference (channels)
To avoid collisions (PCI)
To avoid PRACH root sequence index collisions (PRACH RSIs)
Tool based on an iterative cost-based algorithm
The algorithm starts with the current frequency plan (used as initial state)
Different frequency plans are then evaluated and a cost is calculated for each of them
The best frequency allocation plan is the one with the lowest global cost
Forsk 2015 Confidential Do not share without prior permission Slide 76
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AFP Overview (2/2)
The cost is calculated thanks to:
Interference matrices
Probabilities of interference in co- and adjacent channel cases
A probability is calculated for each case and for each interfered-interfering cell pair
Distance relation
Avoid frequency reuse between cells for which the inter-site distance is lower than a min. reuse distance
Taking into account distance and cells azimuth
Neighbours
Taking into account neighbours importance (can be calculated by Atoll)
Forsk 2015 Confidential Do not share without prior permission Slide 77
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Automatic Resource Allocation Process
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Define radio parameters at cells level
Frequency band allocation
Allocation status: not allocated or locked
Minimum reuse distance (optional)
Import / calculate a neighbour plan
Import / calculate an interference matrix
Run the automatic resource allocation tool
Commit and analyse results
-
Interference Matrix Calculation (1/2)
Interference matrix definition
For each cell pair, interference probability for co and adjacent channel cases
Probabilities of interference are stated as the ratio between:
The interfered area within the best server area of the victim
Best server area of the victim
Co-channel interference occurs when:
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TX_A Victim Transmitter
Serving Area
TX_B Interfering Transmitter
Area where TX_B is interfering TX_A
Interference probability = 50%
In other words, 50% of TX_As serving area is interfered by TX_B
Signal Reference
N
CMin
NMI
C
Q
Slide 79
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Interference Matrix Calculation (2/2)
Forsk 2015 Confidential Do not share without prior permission Slide 80
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Physical Cell ID Overview
Physical Cell ID definition
Cell search and identification is based on Physical Cell IDs
Optimised allocation needed to avoid unnecessary problems
in cell recognition and selection
504 Physical Cell IDs defined by 3GPP
Physical Cell ID grouped into:
168 unique Cell ID groups (SSS IDs in Atoll, from 0 to 167)
Each group containing 3 unique identities (PSS IDs in Atoll, from 0 to 2)
Each cells reference signal transmits a pseudo random sequence corresponding to the Physical Cell ID of the cell
When Physical Cell ID + pseudo-random sequence is known, cell is recognized by mobile based on the received reference signal
Channel estimation performed on reference signals
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(Cell search procedure)
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Physical Cell ID Allocation Process
PCI allocation to cells
Main requirement
Avoid PCI collision and confusion
Not allocate the same PCI to nearby cells
To avoid problems in cell search and selection
Secondary requirements
Different PSS ID at nearby cells
Avoid RS-RS collisions
Preferably the same SSS ID at co-site cells (especially in the case of 3-sector sites)
May facilitate neighbour cell identification
May help in measurements and handover procedures
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PCI A PCI A
PCI collision
PCI A PCI B
PCI B
PCI confusion
Slide 82
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Running the Automatic Resource Allocation (1/6)
Forsk 2015 Confidential Do not share without prior permission Slide 83
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Running the Automatic Resource Allocation (2/6)
Automatic resource allocation process
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Allocation constraints
Possibility to allocate channels or Physical Cell IDs
Run the calculation
Slide 84
-
Running the Automatic Resource Allocation (3/6)
Automatic resource allocation process
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Possibility to allocate channels or Physical Cell IDs
Run the calculation
Slide 85
Allocation constraints
-
Running the Automatic Resource Allocation (4/6)
During the optimisation, you can monitor the reduction of the total cost
Forsk 2015 Confidential Do not share without prior permission Slide 86
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Running the Automatic Resource Allocation (5/6)
You can compare the distribution histograms of the initial and current allocation plans
Forsk 2015 Confidential Do not share without prior permission Slide 87
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Running the Automatic Resource Allocation (6/6)
Once Atoll has finished allocating Physical Cell IDs, the proposed allocation plan is available on the Results tab
The proposed PCI plan can be assigned automatically to the cells of the network if you click Commit
Forsk 2015 Confidential Do not share without prior permission Slide 88
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Physical Cell ID Allocation Results (1/2)
Automatic Physical Cell ID allocation in Atoll (example)
Same PCI all over - RS coverage C/(I+N) with DL traffic load = 0%
Forsk 2015 Confidential Do not share without prior permission Slide 89
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Physical Cell ID Allocation Results (2/2)
Automatic Physical Cell ID allocation in Atoll (example)
Automatic PCI allocation with AFP - RS coverage C/(I+N) with DL traffic load = 0%
Forsk 2015 Confidential Do not share without prior permission Slide 90
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Automatic Frequency Planning (1/2)
Philosophy of the channels automatic allocation is really similar to PCI allocation
Automatic channels allocation prerequisites
Define radio parameters at cells level
Frequency band
Channel allocation status
Minimum reuse distance
Neighbour plan
Interference matrix (as explained previously)
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Automatic Frequency Planning (2/2)
Philosophy of the channels automatic allocation is really similar to PCI allocation
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Frequency Allocation Examples (1/2)
Basic frequency allocation (Single Frequency Network)
Same channel all over (15 MHz) - RS coverage C/(I+N):
Forsk 2015 Confidential Do not share without prior permission Slide 93
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Frequency Allocation Examples (2/2)
Optimised frequency allocation with AFP
3 channels (5 MHz) - RS coverage C/(I+N):
Forsk 2015 Confidential Do not share without prior permission Slide 94
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Find on Map Tool Overview
You can visualise channels and PSS ID reuse on the map
Possibility to find cells which are assigned a given:
Frequency band + channel
Physical Cell ID
PSS ID
SSS ID
Way to use this tool
Create and calculate a coverage by transmitter with a colour display by transmitter
Open the Find on map tool available in the tools menu
or use [Ctrl+F],
or directly in the toolbar
Forsk 2015 Slide 95 Confidential Do not share without prior permission
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Channel Search
Channel reuse on the map
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Colours given to transmitters: Red: co-channel transmitters Yellow: multi-adjacent channel (-1 and +1) transmitters Green: adjacent channel (-1) transmitters Blue: adjacent channel (+1) transmitters Grey thin line: other transmitters
Slide 96
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Physical Cell ID Search
Physical Cell ID, PSS ID or SSS ID reuse on the map
Forsk 2015 Confidential Do not share without prior permission Slide 97
Colours given to transmitters: Red or grey thin line: if the transmitters carries or not the specified resource value (Physical Cell ID, PSS ID or SSS ID)
-
You can check if your constraints are satisfied by the current allocation by performing an audit
Respect of a minimum reuse distance
Respect of neighbourhood constraints (two neighbour cells must have a different PCI)
Respect of PSS/SSS ID allocation strategy
PCI Allocation Audit (1/2)
Forsk 2015 Confidential Do not share without prior permission Slide 98
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PCI Allocation Audit (2/2)
Audit results
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The exclamation mark icon ( ) means that the collision may or may not be a problem depending on your network design rules and selected strategies. On the other hand, the cross icon ( ) implies an error.
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Automatic PRACH RSI
PRACH channel
PRACH RSI Planning Theory
Automatic PRACH RSI Planning
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PRACH Channel
The Physical Random Access CHannel (PRACH) is used to transmit the random access preamble used to initiate the random access procedure. This channel allows UEs to achieve uplink time synchronisation
PRACH resources are multiplexed with PUSCH and PUCCH
Forsk 2015 Slide 101 Confidential Do not share without prior permission
CYCLIC
PREFIXSEQUENCE
GUARD
TIME839 subcarriers for preamble format 0 to 3 => 6 RB
139 subcarriers for preamble format 4
Duration depends on the preamble format
1.25 kHz wide Subcarriers for formats 0 to 3 7.5 KHz wide Subcarriers for format 4
Contention-free random Access Procedure
-
PRACH Channel
Different sections of the network can be planned with different preamble formats if the cell range varies from one area to another
The format 0 is the default format as it generates a small overhead and allows reaching a maximum cell range of 15 km which the most common situation
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Preamble
Format
Duplex
Mode
Cyclic Prefix
Duration
Sequence
Duration
Guard
Time
Total
Length
Typical Max.
Cell Range
0 FDD/TDD 103,13 us 800 us 96,88 us 1 ms 14,5 km
1 FDD/TDD 648,38 us 800 us 515,63 us 2 ms 77,3 km
2 FDD/TDD 203,13 us 800 us 196,88 us 2 ms 29,5 km
3 FDD/TDD 684,38 us 800 us 715,63 us 3 ms 100,2 km
4 TDD 14,58 us 133 us 9,38 us 0,16 ms 1,4 km
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PRACH RSI Planning Theory
Purpose: Determine different preamble sequences to allow multiple UE using the same frequency and time domain resources to simultaneously connect to an eNB. Each sequence is generated by cyclic shifting one or several root sequence index (RSI).
Preamble sequences are CAZAC* codes generated using the Zadoff-Chu method
Each cell has 64 preamble sequences (16 were available for UMTS/HSPA)
838 RSI are available for FDD (format 0 to 3) and 138 for TDD (format 4).
Depending on the PRACH format (or cell size), a different quantity of RSI is required per cell.
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* CAZAC: Constant Amplitude Zero Autocorrelation
15 km
RSI 10-19 4 km
RSI 0-2
Suburban-Rural Cell 10 RSI required per cell
Urban Cell 3 RSI required per cell
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PRACH RSI Planning Theory
The root sequence index values allocated to each cell should ensure that neighbouring cells have different sets of root sequences
A maximum RSI re-use can be implemented when a minimum number of RSI is used
For the urban case, 3 RSI are necessary per cell. 838 different RSI are available, so 838/3 279 cells can be allocated before reuse
For the rural case, 10 RSI are used per cell 838/10 83 cells can be allocated before reuse
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Suburban-Rural Cell 10 RSI required per cell
Urban Cell 3 RSI required per cell
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PRACH RSI Planning Theory
Atoll will allow the user to directly enter the number of required root sequence per cell.
This approach provides the most flexibility in case of different equipment and propagation environments imply additional delays and margins which impact the calculation of the quantity of required root sequence per cell.
The mapping tables show values calculated for ideal conditions, i.e., no delay spread and perfect equipment. There are shown for information only .
3GPP parameters used for the PRACH RSI allocation are described in the following table
Forsk 2015 Slide 105 Confidential Do not share without prior permission
Parameter Range Description
PRACH Configuration Index 0 to 63 Determines the preamble format, version and density
Zero Correlation Zone 0 to 15
Determines the size of the cyclic shift and the number
of preamble sequence that can be generated from each
root sequence
High Speed Flag True/False Reduce Doppler effect at very high speed (> 200 km/h)
Root Sequence Index 0 to 837Preamble sequence generated form root sequence
index
PRACH Frequency Offset 0 to 94Determines the PRACH preambles position in the
frequency domain
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Automatic PRACH RSI Planning (2/8)
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Automatic PRACH RSI Planning (3/8)
Automatic resource allocation process
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Allocation constraints
Resource selection
Run the calculation
Slide 107
Initial cost calculation before planning
Cell parameters
-
Automatic PRACH RSI Planning (4/8)
Automatic resource allocation process
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Specify PRACH RSI resources to be used for the allocation
Slide 108
Allocation constraints
-
Automatic PRACH RSI Planning (5/8)
Once Atoll has finished allocating PRACH RSIs, the proposed allocation plan is available on the Results tab
The proposed PRACH RSI plan can be assigned automatically to the cells of the network if you click Commit
Forsk 2015 Confidential Do not share without prior permission Slide 109
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Automatic PRACH RSI Planning (6/8)
A quantity of 10 PRACH RSIs has been automatically allocated per cell because of the cell table configuration
Forsk 2015 Confidential Do not share without prior permission Slide 110
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Automatic PRACH RSI Planning (7/8)
The LTE prediction, Cell Identifier collision zones, allows verifying if any collisions occur between cells with one or several identical PRACH RSIs
Forsk 2015 Confidential Do not share without prior permission Slide 111
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You can check if your constraints are satisfied by the current allocation by performing an audit
Respect of a minimum reuse distance
Respect of neighbourhood constraints (two neighbour cells must have different PRACH RSIs)
Interference matrix consideration
Automatic PRACH RSI Planning (8/8)
Forsk 2015 Confidential Do not share without prior permission Slide 112
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1. LTE Concepts
2. LTE Planning Overview
3. Modelling a LTE Network
4. LTE Predictions
5. Neighbours Allocation
6. Automatic Resource Allocation
7. MIMO Features
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Training Programme
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8. MIMO Features
Introduction
MIMO Techniques Overview
MIMO Settings in Atoll
Dynamic MIMO Switching
Diversity and Throughput Gains
Calculation Details
Use Case: 4x2 MIMO (TX DIV+SU-MIMO)
Forsk 2015 Confidential Do not share without prior permission Slide 114
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Introduction (1/2)
Shannons formula
Theoretical limit to transmit without error: = . 2(1 + SNR) , (bits/s)
How to increase the channel capacity ?
Increase the bandwidth (W )
Improve the Signal to Noise Ratio (SNR )
Limitation of SISO* systems to reach very high data rates
Why MIMO ?
The usage of multiple antennas improves dramatically the channel capacity without additional bandwidth or transmit power
Expected benefits with MIMO
Higher throughput
Better coverage
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*SISO: Single Input Single Output
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Introduction (2/2)
General concept of MIMO
Multiple Input Multiple Output (MIMO) configurations benefit from multiple antenna elements at the transmitter and multiple antenna elements at the receiver
Terminology
Similar terminology is used for Single Input Multiple Output (SIMO), Multiple Input Single Output (MISO), and Single Input Single Output (SISO)
Forsk 2015 Slide 116 Confidential Do not share without prior permission
Propagation
channel
4x2 MIMO
Propagation
channel
1x4 SIMO
Propagation
channel
4x1 MISO
Propagation
channel
SISO
-
MIMO Techniques Overview
Four different MIMO techniques can be listed
Forsk 2015 Confidential Do not share without prior permission Slide 117
Transmit diversity
Aims to improve the signal quality by sending several times the same data stream
Usually used in areas with bad CINR conditions
Single-User MIMO (or SU-MIMO, also referred to as Spatial Multiplexing)
Aims to improve the signal throughput by transmitting simultaneously (i.e. using the same set of time/frequency resources) multiple data streams to a single user
Usually used in areas with good CINR conditions
Beamforming
Aims to improve both signal quality and throughput by focusing the signal energy towards the receiver
Multi-User MIMO (or MU-MIMO)
Aims to improve the system capacity by sending simultaneously different data streams to different users
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Transmitters Settings
You have to set the appropriate number of antenna ports at the Transmitters level
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In this example, 4 ports are defined for the transmission (used for DL calculations), and 2 ports for the reception (used for UL calculations)
Propagation
channel
4x? MIMO (DL)
?
Propagation
channel
?x2 MIMO (UL)
?
Depends on the number of reception antenna ports defined in the terminal properties (see slide 49)
Depends on the number of transmission antenna ports defined in the terminal properties (see slide 49)
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Cells Settings
MIMO techniques support
You can define the MIMO techniques supported by your equipment in UL/DL in the Cells properties
AAS = Active Array System (beamforming)
For more information see the training course LTE Features Advanced
MU-MIMO
For more information see the training course LTE Features Advanced
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Tx/Rx diversity
UL/DL
SU-MIMO
UL/DL
AAS
DL only
MU-MIMO
UL/DL
-
Terminal Settings
You have to configure a terminal that supports MIMO
Forsk 2015 Slide 120 Confidential Do not share without prior permission
MIMO support
Number of antenna ports in UL and DL in case of MIMO support (1Tx/2Rx is the most common configuration at the moment)
LTE equipment defining SU-MIMO and diversity gains
-
Definition
Atoll can dynamically switch between different MIMO techniques depending on the radio condition
Different option can be implemented:
TX DIV SU-MIMO, TX DIV MU-MIMO, TX DIV MU-MIMO SU-MIMO
In this example, Atoll can automatically switch from SU-MIMO to Tx/Rx diversity as the radio conditions deteriorate
Advantages
Improves the throughput for users situated near the transmitter
Increases the signal quality for cell edge users
Dynamic MIMO mode (1/3)
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Good radio conditions -> Use of SU-MIMO -> Better throughput
Bad radio conditions -> Use of Tx/Rx diversity -> Better CINR
Transition area between SU-MIMO and Tx/Rx diversity -> Determined by the SU-MIMO threshold (see next slide)
-
The SU-MIMO threshold is the parameter used to switch from SU-MIMO to Tx/Rx diversity
It can be defined in the reception equipment properties
Default Cell Equipment (for UL calculations)
Default UE Equipment (for DL calculations)
It is expressed in dB and refers to the Reference Signal or the PDSCH/PUSCH quality
Dynamic MIMO mode (2/3)
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The SU-MIMO threshold depends on the user mobility
-
You can choose the criterion the SU-MIMO threshold will be based upon in the LTE global settings
Reference Signal C/N or C/(I+N)
PDSCH or PUSCH C/(I+N)
Dynamic MIMO mode(3/3)
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Diversity and/or throughput gains can be applied when using certain MIMO techniques
They depend on the MIMO configuration used (2x1 MIMO, 2x2 MIMO, 4x4 MIMO)
Besides PDSCH and PUSCH, PBCH and PDCCH can also benefit from diversity gains
All values set here should be in line with your vendor specific equipment
Diversity and Throughput Gains (1/2)
Forsk 2015 Confidential Do not share without prior permission Slide 124
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Diversity and Throughput Gains (2/2)
Additional diversity and throughput gains are defined in the clutter classes properties
Diversity and throughput gains can be tuned according to the environment
Forsk 2015 Confidential Do not share without prior permission Slide 125
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Calculation Details (1/2)
CINR improvement with the transmit diversity technique
Lets consider for instance the CINRPDSCH
Forsk 2015 Confidential Do not share without prior permission Slide 126
CINRPDSCH (With MIMO) = CINRPDSCH (Without MIMO) + Diversity Gain + Additional Diversity Gain (DL)
-
Calculation Details (2/2)
Throughput improvement with the SU-MIMO technique
Lets consider for instance the DL peak RLC channel throughput
Forsk 2015 Confidential Do not share without prior permission Slide 127
Peak Th. (With MIMO) = Peak Th. (Without MIMO) x [ 1 + (Max MIMO Gain 1) x LTE SU-MIMO Gain Factor ]
-
Use Case: 4x2 MIMO DL (TX DIV+SU-MIMO) (1/5)
Atoll configuration
4 transmission antenna ports
Transmitters properties
2 reception antenna ports
Terminal properties
Diversity support (DL)
TX DIV + SU-MIMO
Forsk 2015 Confidential Do not share without prior permission Slide 128
Note: Traffic load (DL) = 75%
-
Use Case: 4x2 MIMO DL (TX DIV+SU-MIMO) (2/5)
Peak RLC Channel Throughput Analysis (DL)
Conditions:
Traffic load (DL) = 75%
Channel width = 10 MHz
Normal CP, PDCCH overhead = 2
SU-MIMO threshold = 12 dB (RS CINR)
Service = High Speed Internet
Mobility = Pedestrian
Forsk 2015 Slide 129 Confidential Do not share without prior permission
Without MIMO
4x2 MIMO (TX DIV+SU-MIMO)
SU-MIMO threshold
Tx/Rx diversity
SU-MIMO
-
Use Case: 4x2 MIMO DL (TX DIV+SU-MIMO) (3/5)
Peak RLC Channel Throughput Analysis (DL) near the transmitter
Results based on pixels where the SU-MIMO technique is used (RS CINR > 12 dB)
Forsk 2015 Slide 130 Confidential Do not share without prior permission
0
10
20
30
40
50
60
70
80
90
100
0 5 10 15 20 25 30 35 40 45 50 55 60 65 70
Peak RLC Throughput (Mbps)
Without MIMO
AMS 4x2
* AMS: Adaptive MIMO Switching between TX Div and SU-MIMO
-
Use Case: 4x2 MIMO DL (TX DIV+SU-MIMO) (4/5)
Quality analysis - PDSCH C/(I+N)
Conditions:
Traffic load (DL) = 75%
Channel width = 10 MHz
Normal CP, PDCCH overhead = 2
SU-MIMO threshold = 12 dB (RS CINR)
Service = High Speed Internet
Mobility = Pedestrian
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Without MIMO
4x2 MIMO (TX DIV+SU-MIMO)
SU-MIMO threshold
No service
Tx/Rx diversity
SU-MIMO
-
Use Case: 4x2 MIMO DL (TX DIV+SU-MIMO) (5/5)
Quality analysis - PDSCH C/(I+N)
The overall quality (near transmitter and at cell edge) is considered on the chart below
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0
10
20
30
40
50
60
70
80
90
100
-20 -15 -10 -5 0 5 10 15 20 25 30
PDSCH C/(I+N) (dB)
Without MIMO
AMS 4x2
* AMS: Adaptive MIMO Switching between TX Div and SU-MIMO
-
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Appendix
Slide 133
-
LTE throughput formulas
Downlink Peak RLC channel Throughput
=
Number of Ressource Elements available for PDSCH
Bearer Efficiency : Number of bits per symbol * Coding rate
Frame duration : 10 ms
Downlink Effective RLC channel throughput
= ( )
BLER: Downlink block error rate read from the graphs available in LTE Network Settings / Reception Equipment
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-
LTE throughput formulas
Downlink Application channel throughput
=
Throughput scaling factor defined in the properties of the service used by the pixel (Traffic parameters / Services)
Throughput offset defined in the properties of the service used by the pixel (Traffic parameters / Services)
Downlink peak RLC cell capacity
= . .
T.L.: Maximum Downlink Traffic Load
Downlink effective RLC cell capacity
= ( )
BLER: Downlink block error rate read from the graphs available in LTE Network Settings / Reception Equipment
Peak Cell Capacity: Downlink Peak RLC Cell capacity (kbps)
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-
LTE throughput formulas
Downlink Application cell capacity
() = ( )/
Throughput scaling factor defined in the properties of the service used by the pixel (Traffic parameters / Services)
Throughput offset defined in the properties of the service used by the pixel (Traffic parameters / Services)
Downlink peak RLC throughput per user
=
N DL users: Number of users connected to the cell in downlink
Downlink effective RLC throughput per user
=
N DL users: Number of users connected to the cell in downlink
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-
LTE throughput formulas
Downlink application throughput per user
=
NDL users: Number of users connected to the cell in downlink
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-
RSRQ formula
RSRQ is the ratio over the entire channel bandwidth of the wanted RS signal / All signal
=
RSRP: Received Signal Received Power: Received Power at the UE per Reference signal channel resource element from its serving cell
RSSI: Received Signal Strength Indicator: Total power received at the UE from its serving and adjacent cells
NRB : Number of resource blocks over which the RSSI is measured
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Thank you
Slide 139