TABLE OF CONTENTS The link budget determines the necessary parameters for a successful transmission of a signal from a transmitter to a receiver through space. The term link refers to linking or connecting the transmitter to the receiver which is done by means of sending out radio frequency (RF) waves through space. The term budget refers to the allocation of RF power, gains and losses, and noise throughout the entire system including the link between the transmitter and the receiver. The main items that are included in the budget are the required power output level from the transmitter power amplifier, the gains and losses throughout the system and link, and the signal-to-noise level required at the receiver to produce the desired bit error rate or the probability of detection and probability of false alarm. Therefore, when certain parameters are known or selected, the link budget allows the system designer to calculate unknown parameters.
Several of the link budget parameters are given or chosen during the process and the rest of the parameters are calculated. There are many variables and tradeoffs in the design of a transceiver; each one needs to be evaluated for each system that is being designed. For example, there are tradeoffs between the power output required from the power amplifier and the size of the antenna. The larger the antenna (producing more gain) the less power is required from the power amplifier. However, the cost and size of the antenna may be too great for...
