Signals can be transported wirelessly, without the use of wires or optical fibers. In this instance, signals travel across free space. 

What is the process of wireless communication?

We need wireless data transportation in order to enable wireless communication. We use electromagnetic waves, or signals, to transfer this data. The question now arises: how can a signal be generated for wireless transmission? Everything begins at the transmitter, where a periodic wave is produced by an oscillator. This signal travels up to the antenna via the device's internal wires. Electric current flows farther toward the end of the antenna because it is a conductor. The alternating current is then released by the antenna as an electromagnetic wave. Here is where wireless technology begins, when an antenna transforms electrical current into waves.

The signal's frequency

The frequency of the output waves varies with the oscillator's signal change rate. There are various uses for these frequencies. A spectrum is the range of distinct frequencies. It is separated into sections for particular uses. Examples of applications include satellites, ISM bands, broadcasting, mobile communication, radio-navigation, radio-location, and space research, among many others. The FCC and other government agencies are in charge of designating frequency ranges for particular uses.

How are signals sent?

Typically, a signal is transmitted and then not received directly by the receiver. The signal is radiated in multiple directions by the transmitter's antenna. Waves can still reach their destination even if they scatter off of small objects, diffract on sharp edges, or reflect off of buildings. Waves experience various delays and attenuations as they travel. Each one is picked up by the receiver as a single signal. We refer to a channel that has multiple paths connecting the transmitter and receiver as a multipath channel.

Inside the transmitter

It is well known that in order to decode the data, the receiver must handle a distorted and mixed signal. Given the quantity of unwanted components in the captured signal, this is not a simple task. We take a few extra steps in the transmitter to simplify this task. The transmitter does encoding prior to transmitting user data. By appending extra bits to the message, this operation facilitates data recovery for the recipient. Bits are modulated, mapped onto symbols, and sent to the antenna after encoding.