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Radio Models

In this section a joint model of Baseband and RF up/down-conversion is described. The model is primarily driven by the following input parameters:

RF Front End​

This module interfaces with the antenna subsystem and the Baseband. The key functionality of this module is to up/down-convert the signals to/from higher frequencies (mixing).

  • Maximum Tx Power: Maximum Transmit Power in dBm. Different manufacturers have different limits on the maximum allowed transmit power. The transmit power control (TPC) algorithm programmed in the tool will use this as the upper limit while trying to identify the best transmit power for each unit.
  • Minimum Tx Power: Minimum Transmit Power in dBm. Similar to the Max Tx power, there is a minimum Tx power for each manufacturer’s equipment and is also used as a lower limit in the TPC algorithm.
  • Maximum EIRP: Maximum Equivalent/Effective Isotropically Radiated Power in dBm. This is typically set by the regulatory bodies in the deployment area. The TPC takes this into account and caps the max power such that the sum of Tx power and antenna boresight gain does not exceed the Maximum EIRP limit.
  • Tx Miscellaneous Loss: Miscellaneous losses on the transmitter in dB. These can include, but not limted to cable/connector losses, RF hardware mismatch losses.
  • Rx Miscellaneous Loss: Miscellaneous losses on the receiver in dB. These can include, but not limited to cable/connector losses, RF hardware mismatch losses.
  • Frequency: Frequency (in MHz) at which these sectors operate.
  • Noise Figure: A critical link budget factor that degrades the received SNR. The Noise Figure (NF) is defined in dB and formulated in log scale as the degradation of SNR. i.e. NF = SNR input - SNR output. In Link Budget Calculations we show the formulation on NF in link budget calculation

Baseband​

The Baseband module, as a receiver, receives down-converted signals from the RF front end and extracts data (as bits) from these signals. As a transmitter, provides input signals to the RF front-end for up-conversion to higher frequencies. The following terms are tied to the SNR gains achieved

  • Tx Diversity Gain: Transmitter diversity gain in dB. This could be achieved due to polarization diversity or any other spatial diversity scheme.
  • Rx Diversity Gain: Receiver diversity gain in dB. This could be achieved due to polarization diversity or any other spatial diversity scheme.
  • Minimum MCS Level: The minimum MCS level allowed. This could be forcefully set to a higher value to always guarantee a certain MCS in all links.
  • Thermal Noise Power: Thermal noise power (dBm) is used in the link budget calculations to capture the noise floor level. This is dependent on system temperature and bandwidth used. A detailed formulation is given in Link Budget Calculations.
  • MCS Map File: A CSV file that contains the mapping between MCS, SNR and Mbps where Mbps represents effective download rate. There must be exactly one column with headers ”mcs”, ”snr” and ”mbps”.