Today’s world is connected now more than ever before in history. Gone are the days of wired telegraphs and telephones, limited to one place. Cellular technology and wireless signals have forever changed how humans interact- both with each other and the world around them. Images, sounds, and written messages can be sent almost instantly across long distances, and information can be searched with the touch of a button. With convenient communication as the new normal, it is easy to take these advancements of electronic communication systems for granted. The truth is, it takes many different technologies working in tandem to make such communication possible.
Connecting Without Wires
Wireless signals are the backbone of modern communication- but how do they work? The answer comes in the form of electromagnetic waves, which travel at the speed of light (whether in the air or in a vacuum). The relationship between an electromagnetic wave’s frequency and it’s wavelength can be observed with the formula:
C = fλ
Where “C” represents the velocity of light, “f” represents frequency (measured in Hz), and “λ” represents the wavelength (measured in meters).
Radio waves represent the lowest frequency type of electromagnetic waves, and are subsequently the most widely used waves in telecommunication. The Radio Regulations of the International Telecommunication Union (ITU) identifies about 40 radiocommunication services. The ITU has divided the radio spectrum into bands as a means of convention Below is a chart describing 10 out of these 12 named bands (Anything below ULF is only used for communicating between submarines).
Connecting on a Global Scale
Large-scale electronic communication requires the use of multiple technologies. Let’s take, for example, a standard phone call on a smartphone. Person A is in North Carolina and calls Person B, who lives in Illinois. The phones must first connect to cell towers via cellular links, and then the towers themselves must use microwave links to connect to each other. The cell towers must also connect with wideband fiber-optic cables that comprise the core communication network.
From the depths of the ocean with submarine cables to the heights of space with satellite networks; the structure, intricacy, bandwidth, and dependability of each of these links varies.
Connecting in Layers
In the world of engineering, the vast system of electronic communication can be divided into two essential layers: the physical and the network.
The network layer connects and controls the microwave, cellular, and satellite systems that are found all across the globe. This layer is integral to communicating with the digital logical addresses associated with individual devices. (ex. IP addresses in computers and laptops). The network layer is also responsible for routing data information “packets” across networks. Much like an electronic post office, the network layer receives and processes incoming informational packets from multiple sources, identifies their intended destination, and sends them down the correct path. Diagnostics and errors are also in the domain of the network layer, as logically connected devices are able to share information regarding the status of the device or network host.
The physical layer is made up of the physical channels that transmit data. The responsibilities of this layer include controlling and utilizing the hardware; such as cables, transceivers, connectors, and more. It is important in the design of hardware networks such as LANs (local area networks). The physical layer is also responsible for transforming the data within a computer from bits into signals capable of being sent over the network. This is made possible through encoding and signaling. The physical layer both receives and transmits data through both wireless and wired channels.
“Communications System Laboratory” by B. Preethum Kumar