LDACS1 cell planning

Cell planning for LDACS1 is a prerequisite for a reliable operation of LDACS1.

The requirement is that the cell planning is able to fully serve the expected traffic demand and to provide full coverage of the continental European airspace above Flight Level 100.

We developed a model to approximate the expected ATM traffic load in the future, e.g. in 2020.

traffic_load_new

Based on this model, a cell planning algorithm has been developed. This cell planning algorithm addresses three goals:

  • Complete coverage of the airspace above Flight Level 100.
  • Coverage of 100% of the traffic demand according to the load map.
  • No cell shall be overloaded.

For a cell size between 60 nmi and 120 nmi, a possible cell planning result is shown.

Figure Cell Planning

Besides the placing of the different cells, the planning also includes the frequency assignments of the different cells. Since the L-band is also used by other radio systems, LDACS1 channels are exposed to interference. The level of this interference depends on the geographic location and the channel that is used. An analysis of the current interference conditions revealed that the transmit frequency cannot be chosen arbitrarily. In particular interference from Distance Measuring Equipment (DME) ground stations has to be taken into account. The number of possible frequency assignments for LDACS1, guaranteeing an acceptable low interference level, is shown in the figure below.

num_cells_new

Incorporating this constraint into the cell planning leads to the conclusion that an European deployment of LDACS1 is easily achievable and still leaves significant room for future traffic growth.

Further technical details on the LDACS1 cell planning have been published in several papers presented at international conferences.