LTE Network Planning and Simulation

Coverage and Capacity Prediction for LTE Networks

LTE Air Interface


The LTE air interface is based on OFDM and MIMO - therefore planning tools for 2G or 3G networks cannot be re-used for LTE.

The determination of the interference in OFDM networks (with and without) MIMO is a critical task and requires highly accurate propagation models.



Max. achievable data rates (Throughput)
 for an indoor LTE network
 

Max. achievable data rates (Throughput)
for an urban LTE network
WinProp's ray-optical propagation models and the dominant path model (DPM) for rural, urban and indoor scenarios predict the signal level as well as the LOS/NLOS status and they consider additionally the polarization of the signals (especially important for MIMO antennas).

Parameters of LTE in WinProp


For typical FDD and TDD LTE networks with 5, 10, and 20 MHz bandwidth the properties of the LTE air interface are pre-defined in WinProp (for different frequency bands used for LTE around the world).


The user can additionally modify the following parameters of the LTE settings:

  • Subcarriers and symbols
    • FFT size
    • number of subcarriers (for reference signals, control channels, data, guard, etc.)
    • symbols used for reference signals, control channels, and data transmission
    • number of subcarriers in one resource block
  • Power backoffs for reference, control, and data carriers/symbols (either default for all cells or individually for each cell)
  • Cell assignment mode and min. required thresholds for SNIR and signal level
  • Transmission Modes
    • MCS (modulation and coding)
    • Nr. of resource block used for transmission
    • Min. required SNIR (and optionally signal level)
    • Tx power backoff
  • MIMO
    • 2x2, 2x4, 4x4, etc.
    • Interference between the MIMO streams (depending on polarizations of MIMO streams, LOS/NLOS conditions, etc.)
  • TDD properties (e.g. ratios between UL, DL, guard)
  • ....


SNIR in downlink for QPSK transmission
with code rate 1/8 (and 30% cell load)

Click to enlarge

Min. required Tx power for downlink
 (QPSK, code rate 1/8, 30% cell load)

Simulation of LTE Networks


Besides the classical cell assignment, WinProp's LTE module provides the following simulation results:
  • Cell Assignment
    • cell area
    • max. number of received carriers/transmitters/sites (in downlink)
    • received power in mobile station
    • total received interference and noise 
  • Reference signals and control channels
    • RSRP, RSSI, and RSRQ
    • Received signal level and SNIR for control channels
  • For the mobile stations in the simulation area (i.e. for each pixel in the area):
    • max. achievable data rate for a single user at the pixel (downlink and uplink) incl. gain due to MIMO
    • max. achievable throughput (for multiple users) at the pixel incl. gain due to MIMO
    • number of received MIMO streams (and their signal levels, SNIRs, etc.) in uplink and downlink
  • For each transmission mode at each pixel:
    • min. required Tx power at UE (UL) and Node B (DL)
    • max. received Rx power at UE (DL) and Node B (UL)
    • max. achievable SNIR in downlink and uplink
    • reception probability (DL and UL)



Received power in downlink
(for a selected transmission mode)
for an urban LTE network
The traffic and load assumed in the simulation influences obviously the predicted throughput and capacity. The user can control the traffic via:
  • Cell load for downlink
    To get a realistic assumption of the interference in the downlink, the load can be defined for each cell individually.
    The cell load can either influence the power radiated in the cell (similar to 3G networks) or - more realistic for LTE - the cell load controls the bandwidth (nr of subcarrriers) used for transmission. This reduction of the bandwidth leads to subcarriers without any interference at the borders of the cells. And this increases the coverage area of the cells significantly.
  • Noise rise in uplink
    The user can define the noise rise in the uplink for all cells (identical rise) or for each cell individually.

 

Application Note: 
LTE Network Planning

Application Note:
MIMO Network Planning

Brochure related to
TDMA Network Planning

Publications related to Network Planning

Read more about the
3G Network Planning





Application Notes:

LTE Network Planning
MIMO for LTE Networks




The simulaton of LTE networks requires the WinProp module NET-O (OFDM Networks) .






Click to enlarge


Cell areas of an LTE network
inside a building








3rd Generation Partnership Project (3GPP) defines the long-term evolution (LTE) for 3G radio access.










Further information related to
the WinProp software suite
can be found in the brochures.

MIMO

MIMO is a key technology for the LTE air interface. WinProp considers MIMO in LTE network planning:

  • The number of MIMO streams received in up- and downlink is predicted and for each of the MIMO streams the signal level and SNIR are visualized.
  • Distributed MIMO is possible (the location of each Tx antenna radiating a MIMO stream is defined by the user => arbitrary locations are possible).
  • The MIMO streams of a signal can be assigned to the Tx antennas individually. Multiple antennas can radiate the same MIMO stream (DAS)
  • The interference between the MIMO streams depends on the LOS/NLOS conditions, the signal levels, and the polarizations of the signals (the polarization of each Tx antenna can be defined individually).

LTE Air Interface

3rd Generation Partnership Project (3GPP) defines the long-term evolution (LTE) for 3G radio access.
LTE is designed to meet carrier needs for high-speed data, multimedia unicast and multimedia broadcast services as well as high-capacity voice support.

The main targets for this evolution therefore concern increased data rates, improved spectrum efficiency, improved coverage, and reduced latency.

The basic radio interface principles for the LTE concept include OFDM and advanced antenna solutions (MIMO).