I was reading an article about a specialized communications link, and the author noted that in his case, it was much easier to boost the transmit-side power than improve the receive side. His comment made me think: which end should you work on improving?
In many situations, there is no choice. If you are designing a receiver (such as a GPS receiver or even a basic "radio"), you have no control over the transmit situation. Conversely, in many applications, you only have control over the transit side, and none for the receiver situation.
But for cases where the designer or project team has some control over both, the decision of what to do is a complicated one. You can improve your SNR and BER by boosting the transmit power, but this costs more in terms of a larger PA, more supply power, and has other implications. (And what about the antenna, do you have any control over that?)
Or, you can improve the receiver front end, perhaps with a better, lower-noise front-end amplifier, or better, tighter filters, or even more complex, sophisticated algorithms to process the signal. While a better LNA or filters usually have very modest impact on power consumption, all three can impact the BOM cost. And if the received signal is buried in channel noise, an LNA with lower noise figure may not help.
So, as with most design situations, there is no clear-cut "best "answer or even an easy one. As usual, it's a matter of tradeoffs, with balancing among priorities, constraints, and risks, as well as cost and time-to-market issues. ♦