User guide

34
11 Channel simulator
The LTE UE simulator embeds a channel simulator that can be used to alter UE measurements
and simulate different radio conditions.
The main parameter to activate the channel simulation is: channel_sim
If set to "true", the UE channel simulator is enabled.
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Note: Channel simulator is only available in multi UE mode (multi ue = true).
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On the downlink side, depending on the simulated UE path loss, the channel simulator modifies
the PER (Packet Error Rate) of PDSCH and PDCCH and updates the measured RSRP and
CQI.
On the uplink side, The signal level is modified accordingly. The path loss of each UE is
computed according to the corresponding UE and cell positions, channel and antenna models.
11.1 Cell configuration
When the UE channel simulator is enabled (channel_sim = true), the following additional
parameters must be provided (see lteue.pdf file for more details):
• position
• antenna
• ref signal power
• ul power attenuation
Here is an example of cell configuration defined in ue.cfg file:
bandwidth: 20,
multi_ue: true,
channel_sim: true,
cells: [
{
dl_earfcn: 3350, /* 2680 MHz (band 7) */
n_antenna_dl: 2, /* number of downlink antennas */
n_antenna_ul: 1,
global_timing_advance: -1,
/* position (in meters) */
position: [0, 0],
ref_signal_power: 5, /* in dBm */
/* Attenuation between the UE TX and eNodeB RX in dB. In
LTESIM, it is equal to the path loss of the UE group. */
ul_power_attenuation: 108,
antenna: { type: "isotropic" },
}
],