Differences in terminologies can often lead to confusions but there are also times when they teach us something we didn’t know. The terms mobile phones and cell phones (cellphones) mean the same thing but they bring two very interesting concepts to the fore. While it may be true that the term ‘mobile phone’ is more common in UK & Europe and ‘cell phone’ is more common on the US side, both these terms touch upon two key technical aspects of mobile communications. The same can be said about mobile networks and cellular networks also.
A mobile phone or cell phone communicates through ‘cells’ that are created by mobile networks to provide wireless network coverage. A cell is a coverage area created by the emission of radio waves from the base stations (masts). This inter-connected existence of cells throughout a country allows an operator to keep us connected even when we are on the move (mobile).
How do mobile phones or cell phones use cells?
Let’s have a look at the conceptual diagram below with lots of blue hexagons that represent the cells. A cell basically is just a range within which the transmission and reception of signals between the phone and base station take place. The mobile base stations transmit and receive the radio signals at certain frequencies within a well-defined range, and the mobile phones within this range do the same. For example, if you live in an area covered by cell#1, mobile phones within this area will be mostly served by cell#1 unless it is busy in which case the next closest cell will be able to serve you.
For mobility scenarios e.g. driving, as you move from one location to the next, the serving cell can ‘handover’ your phone call or data session to another cell. This way, your call or data session keeps getting handed over from cell to cell to make sure you stay connected without dropping calls or interrupting data sessions.
The diagram above is for illustration purposes only to highlight the concept. In real life, the cells can be of many different sizes. We will cover two key cell types below. If you want to learn more, you can check out our post on small cells which are more targetted cells often used as “signal boosters”.
Macrocells are the large or regular cells that provide the main mobile network coverage in your area. These cells usually have their antennas mounted at the top of tall masts on the ground, rooftops of high-rise buildings and other similar locations. These cells have a range in tens of kilometres, and they need to be mounted at a height from where they have a (mostly) clear view of the area they are serving. These cells require dedicated sites with adequate power supply, and usually, the operator pays rental fees for these sites. Macrocells form the main layer of the cellular coverage within a geographical area.
Macrocells are installed, operated, controlled and managed by the mobile operator and use a licensed frequency spectrum. Multiple macrocells can originate from the same base station of a cell site. Macrocells have high transmission and reception power which gives them a large range to be able to provide primary network coverage to vast geographical areas. Macrocells can also serve the rural areas very well, such as highways where the traffic load on the mobile network is not as high as that in the cities. The cities have too many obstacles for the signal to travel such as large buildings, thick walls, billboards, and so on. The cities are also densely populated which puts a much greater demand on the required network capacity to accommodate so many users. Macrocells alone cannot address these capacity and coverage challenges and require smaller cells with more targeted coverage and additional capacity to complement them.
Microcells are a type of small cells that are low-powered cellular base stations. They are the biggest of the small cells with a range of up to 2 kilometres. Microcells can be used to add capacity and coverage to the existing mobile network alongside macrocells, picocells and femtocells. Due to the size of the area they can cover, microcells can be a good solution for areas like large train stations and also for addressing temporary capacity needs for any sporting events, concerts, etc.
Microcells are an extension of the primary cellular network (macrocells), and they can provide additional capacity and coverage in densely populated areas. Microcells are controlled and managed by the mobile operators themselves. The key considerations for deploying microcells include the connectivity to the mobile core network, the frequency spectrum and the power supply.
In densely populated areas such as the city centre, there are usually too many obstructions for the macrocell signals. These obstructions reduce the strength of the signal, which makes it harder for the signal to reach mobile phones. The capacity needs in densely populated areas are also higher as lots of people use their mobile phones simultaneously for services like voice calls, video streaming, and browsing etc. This additional capacity can be provided by microcells as well as other smaller cells like picocells and femtocells.