Indoor LTE with Leaky Feeder Cable

Model Type

The model consists of a large single-story building with leaky feeder cables installed along a horizontal path. The cable has apertures along its entire length to allow transmission and reception by means of signal leakage. Amplifiers are used to boost the signal along these cables to improve signal transmission from the transmitter to the receiver.

Sites and Antennas

Instead of using antennas, two leaky-feeder cables running side-by-side are used.

Tip: Click Project > Edit Project Parameter and click the Sites tab to adjust the cable parameters.

The cables use the same carrier frequency of 2112.50 MHz but transmit different MIMO streams.

Note: Click Project > Sites > Site: New and on the Transmitter Type dialog, click Leaky Feeder Cable to define new leaky feeder cables.

Air Interface

The air interface is defined by an LTE wireless standard LTE_LeakyFeeder.wst file. (Orthogonal Frequency division multiple access (OFDM/SOFDMA) was selected for multiple access. Two-streams MIMO technology is used.

Tip: Click Project > Edit Project Parameter and click the Air Interface tab the view the air interface as well as MIMO settings, carriers and transmission modes.

Computational Method

The dominant path model (DPM) is used for the propagation modeling. This computational method focuses on the most relevant path, which leads to shorter computation times compared to ray-optical methods. Empirical losses for transmission, reflection, and diffraction are used for computation of the signal level. These parameters can readily be determined with measurements.

Tip: Click Project > Edit Project Parameter and click the Computation tab to change the model.

Results

Propagation results show at every location the power received from each transmitting cable. Results are available for a single prediction plane at a height of 1.5 m. As the transmitting leaky feeder cables are placed close together, the results are almost identical, see Figure 1 and Figure 2.

The type of network simulation is a static simulation (homogeneous traffic per cell). The network simulation calculates the following:

minimum required transmitter power
maximum achievable received signal strength
reception probability
data rate
maximum number of parallel streams
maximum signal-to-noise-and-interference ratio (SNIR) for all modulation and coding schemes, and for both uplink and downlink

An example of signal-to-noise-and-interference ratio (SNIR) in the downlink is displayed in Figure 3. Near the lower-right corner, both the signal level and the SNIR are low. Consequently, communication in that area is limited to modes with lower data rates.