Link Budget for Communication Systems
Propagation loss, multipath and noise are factors that can prevent ideal communication between a source and destination. To mitigate these challenges, communication systems employ various techniques and hardware components, including directional antennas, transmitter power, low noise amplifiers and filters. A crucial tool for assessing system performance in relation to these parameters is the link budget, which shows the relationship between system characteristics and the pre-detection signal-to-noise ratio (S/N). By employing a link budget, system designers can make informed decisions and determine tradeoffs to achieve a desired S/N ratio.[more]
You can use this Demonstration to explore the tradeoffs involved in communication link design. You can vary the key system parameters carrier frequency (in MHz), transmitter power (in ), path-loss exponent, receiver antenna temperature (in kelvin), receiver noise figure (in dB), bandwidth (in MHz) and transmitter/receiver antenna sizes (in meters). It is worth noting that the relationship among antenna size, configuration and antenna gain can be complex. However, for the purposes of this Demonstration, a parabolic reflector antenna serves as a proxy for the relationship between the relative size of the antenna and its gain. Consequently, the calculated S/N is not valid if the calculated antenna gain (as displayed) is less than 0 dB, as a gain of 0 dB corresponds to an isotropic antenna. This Demonstration calculates the antenna gains. The S/N is presented as a function of the distance between the transmitter and receiver, which influences S/N values over a selected range of distances.[less]
The following parameter definitions and relationships are used:
is the carrier frequency (Hz)
is the transmitter power (W)
is the wavelength with m/s
is the path loss equal to with distance and path loss exponent (dB)
is the antenna gain with parabolic antenna diameter ( is the transmitter and is the receiver)
is the antenna temperature (K)
is Boltzmann's constant
is the bandwidth (Hz)
is the receiver noise figure
 S. Haykin and M. Moher, Introduction to Analog and Digital Communications, 2nd ed., Hoboken, NJ: Wiley, 2007.
 L. W. Couch, Digital and Analog Communications Systems, 7th ed., Upper Saddle River, NJ: Pearson/Prentice Hall, 2007.
 V. S. Frost. "Introduction to Communication Systems: An Interactive Approach Using the Wolfram Language." University of Kansas Libraries. (Jul 5, 2023) kuscholarworks.ku.edu/bitstream/handle/1808/31779/Introduction-to-Communication-Systems-Deployed-V3.cdf?sequence=5&isAllowed=y.