In RF/Wireless system design, it is required to calculate the System Link Budget between transmitter and receiver which requires to know transmitter power and receiver sensitivity. For Software Defined Radio such as NI-USRP and NI VST (Vector Signal Transceivers), the RF parameters are dynamically defined according to user requirements which are used to define the receiver sensitivity.
For RF/wireless system to operate stable, the RF propagation path loss must be lower than the Maximum Allowable Path Loss, by the amount of system link margin. Maximum Allowable Path Loss (MAPL) will define the distance between transmitter and receiver, the bigger the MAPL, the longer the distance which is related the RF propagation environment. RF propagation discussion is out of this article scope.
This article discusses how to calculate USRP sensitivity and the system link budget between its transmitter and receiver, and examples of calculating the System Link Budget and Maximum Allowable Path Loss of the USRP system. USRP-2954 is taken as an example for calculations. The method discussed in this article is valid for other RF systems such as NI VST. The intend audiences are NI USRP and VST users who have basic knowledge of RF transmitter/receiver specifications and RF propagation, such as transmitter power, receiver sensitivity, transmitter-receiver system link budget, noise figure, propagation path loss, antenna gain.