How are RF signals transmitted? Let's talk equipment
For all its simplicity to the end user, Wi-Fi is really an incredibly complex technology. In this series, we "get back to the basics" of the technology.
Wi-Fi is all about data communication, the transferring of information between two or more components. There are three basic requirements for successful communications:
- Two or more devices that want to communicate
- A medium, a means, or a method for them to use to communicate
- A set of rules
Many components contribute to the successful transmission and reception of RF signals but I will focus on the key components.
- First, there is a transmitter which begins the RF communication. The transmitter takes the initial data and modifies the signal using a modulation technique to encode the data into the signal. The transmitter is also responsible for determining the power level of the wave, which is ultimately regulated by local domain authorities (such as the FCC in the United States).
- Next, an antenna collects the signal that it receives from the transmitter and directs the RF waves away from the antenna. As the RF waves move away from the transmitting antenna they move towards another antenna attached to the receiver, which is the final component in the wireless medium. The receiver takes the signal that it received from the antenna and translates the modulated signals and passes them on to be processed.
As we learned last week, the signal is often altered during transmission between the two antennas due to interference and other RF behavior.
So the ultimate question is, will the RF communication work between all the main components? Although I won’t go into in-depth RF calculations, it’s important to highlight a few practical uses of RF measurement.
Many Wi-Fi vendors define signal quality with a term called the signal-to-noise ratio (SNR). The SNR is the difference between the received signal and the background noise level. Data transmissions can become corrupted with a very low SNR which means your communication or data transfer via Wi-Fi will not work very well.
The power level of an RF signal required to be successfully received by the receiver radio is called the receive sensitivity. The lower the power level that the receiver can successfully process, the better the receive sensitivity. All of these radio frequency components and measurements determine the Wi-Fi experience you have when you connect your mobile device to a wireless access point.
Next week I will discuss the evolution of the wireless standards and how the mobility evolution mirrors these standards.
All Posts In The Back To Basics Series: