WCDMA Network Planning

Coverage and Capacity Prediction for WCDMA Networks

UMTS: WCDMA Air Interface


The UMTS air interface is based on CDMA  - therefore planning tools for GSM/EDGE networks cannot be re-used for UMTS.

The determination of the interference in CDMA networks (with and without) MIMO is a critical task due to the cell breathing and requires highly accurate propagation models.

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).



Max. achievable data rates (Throughput) for an urban
WCDMA network (incl. HSPA and code combining)

Parameters of WCDMA in WinProp


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

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

  • Parameters related to the spreading
    • Chiprate
    • Bandwidth
  • Power backoffs for pilot, control, and data codes (either default for all cells or individually for each cell)
  • Cell assignment mode and min. required thresholds for SNIR (Ec/N0) and signal level
  • Transmission Modes
    • MCS (modulation and coding)
    • Number of parallel codes (HSPA)
    • Min. required Eb/N0 (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)
  • ....



Eb/N0 in downlink for QPSK transmission
with code rate 1/2 and spreading factor 32

Simulation of UMTS Networks


Besides the classical cell assignment, WinProp's NET-C 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 
  • Control channels
    • 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 Ec/N0 and Eb/N0 in downlink and uplink
    • reception probability (DL and UL)



Max Throughput in a WCDMA network
with HSPA (incl. code combining)
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 load controls the Tx power of the antenna in the cell.
  • 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






Simulaton of WCDMA networks requires the WinProp module NET-C (CDMA Networks) .






3rd Generation Partnership
Project (3GPP) defines the
WCDMA for 3G radio access.







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

MIMO

MIMO is an optional technology for the WCDMA air interface. WinProp considers MIMO in WCDMA 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).

WCDMA Air Interface


3rd Generation Partnership Project (3GPP) defines the WCDMA air interface for 3G radio access. The original scope of 3GPP was to produce Technical Specifications and Technical Reports for a 3G Mobile System based on evolved GSM core networks and the radio access technologies that they support (i.e., Universal Terrestrial Radio Access (UTRA) both Frequency Division Duplex (FDD) and Time Division Duplex (TDD) modes). In the meantime 3GPP has released many specifications for the UMTS air interface (starting with Release 1999 and continued till release 12).
WinProp is compliant to all releases of 3GPP and will be updated in case of further releases.