I am sure you must be curious about how a Mobile Phone makes A Call. And how someone from across the World can easily communicate with you from way out. In this post, we are going to handle all aspects related to Mobile Phone communication.
When you speak on your phone, your voice is being carried out in your phone’s microphone. This microphone converts your voice (Analog) into Digital (0 and 1). An antenna inside the phone receives this Zeros and Ones (0 and 1), and then transmits it into the form of Electromagnetic (E.M) Waves by manipulating the Amplitude, the Frequency, and Phase of this waves or a combination of those three aspects. So if these waves from Let’s Say, User A gets to User B, then you are into a conversation or a call. But it is not as easy as it may sound, as these Waves get weakened with distance and obstacles (Houses, Environment,a nd equipments)
To overcome these issues, Cell Towers were used, these Cell Towers make use of Cellular Technology. In Cellular Technology a Geographical location is divided into Hexagonal Cells, Each cell has it’s own Tower and frequency slot.
These Cells are then interconnected via the use of Fibre optic cables. These cables can span from hundreds of metres to several Thousands of Kilometres. The Em waves from your phones are then picked up by these towers, which then converts them to high-frequency light pulses and they are then carried to the Base Transmitter Box at the Base Station for further Signal processing, after processing your Voice signal is then routed to the Destination Tower. Due to the scope and complexity of these Transmissions, we would assume that the Receiver is located at his permanent Base Station. Upon receiving this signals the Destination Base Station then transmits it to EM waves. Then Receiver B then receives the signal. This signal then goes through a Reverse process then your Receiver can hear your voice.
Wait, I know you must be having this question in Mind.
How does Caller A’s Mobile Tower knows where Receiver B’s Mobile Tower is? Well it does that with the help of a Mobile Switching Centre (MSC).
Once you purchase a New Sim card let’s say in Mile One Limbe, Cameroon and you stay in New Town Limbe, Cameroon. The MSC controlling New Town is your Home MSC. Once you switch on your phone, This MSC stores all the information related to you:
- Service Plans
- Current Plan
- Activity Status
Once you move out of Limbe to let’s say Molyko Buea to do a Transaction for a day, the MSC in Molyko Buea would then be your Foreign MSC. This MSC then communicates with your home MSC for it to know where you are at the point.
Importance of Frequency Ranges
Each user is allocated a Frequency on the Spectrum. How ever the Frequency Spectrum associated with 4G is quite limited: 1930 – 1945 Mhz , due to the advent of Technology and the multiple devices we all use, the spectrum can become congested. This issue is sorted out by:
- Frequency Slot distribution: Different Frequency Slots are carefully allocated to different Cell towers
- Multiple Access Technique: Frequency slot are given to the most active users.
Generations of Mobile Communication
It should be noted that there are Generations of Mobile Communication namely: 1G, 2G, 3G, 4G, 5G. But we would limit the context of this post to 1G, 2G, 3G and 4G.
1G enabled users to carry phones for the First time without the use of cables. 1G used Analog signals. The Data Rates for 1G is 2.4 kps
But 1G suffered because Analog signals are easily altered and they lose their quality. These factors then paved the way for the Second Generation of Communication called 2G. 1G used Frequency Division Multiple Access (FDMA)
2G used Digital Access technologies called Code Division Multiple Access (CDMA) and Time Division Multiple Access (TDMA). 2G also introduce a Data service and we had speeds of up to 50kbps. We had SMS and Internet technology.
3G was focused on giving higher data rates and Bandwidth. It used Wideband Code Division Multiple Access (WCDMA) and could reach speeds of up till 2Mbps. It allowed the use of data for uses such as GPS, Video calls and many more.
4G introduced speeds from 20-100Mbps. This was suitable for High-Resolution Movies and Television. Thes speeds were due to the Orthogonal Frequency Division Multiple Access (OFDMA) and Multiple Input Multiple Output (MIMO). MIMO uses multiple Sender Receiver Antennas both on the Phone and on the Towers.
5G uses enhanced MIMO technology and Millimetre waves and it’s expected to achieve speeds of up to 10Gbps. It would provide the Technology to connect the Internet of Things (IoT).