A link budget is the comprehensive accounting of every gain and every loss in a wireless communication path from transmitter to receiver. It determines whether a signal arriving at the far end of the link will be strong enough to be decoded successfully. Engineers start with the transmit power, add antenna gain, subtract cable and connector losses to calculate EIRP, then subtract the path loss over the distance to the receiver, and finally compare the resulting received power against the receiver sensitivity threshold. A positive link margin means the link works reliably.