A common way that people get online is through their mobile phones. Did you know that most mobile phones can be connected to many different types of networks simultaneously? Let’s review some of the ways that mobile phones, smart phones in particular, interact with the various network technologies and learn some new terminology in the process.
Mobile phones use radio waves to transmit voice signals to antennas mounted on towers located in specific geographic areas. Mobile phones are often referred to as “cell phones” because the geographic area in which an individual tower can provide a signal to a phone is called a cell. When a telephone call is made, the voice signal is relayed from one tower to another tower until it is delivered to its destination. This type of network is used when you make a phone call to another mobile phone or to a wired telephone. It is also used to send text messages directly from the phone. The most common type of cellular telephone network is called a GSM network, an abbreviation of the title “Global System for Mobile Communications”.
Sending Data over Cell Phone Networks
The design of the first cell phone radio transmitters did not allow for the efficient transmission of digital data, so enhancements were made to improve the way that data is sent across cell phone networks. The abbreviations 3G, 4G, and 4G-LTE are used to describe enhanced cell phone networks that are optimized for the fast transmission of data. The “G” in these designations represents the word “generation”, so 3G is the third generation of the cell network. Most mobile phones and smart phones have an indicator that shows when a 3G or 4G signal is available. When that indicator is not lit, the phone is connecting through the older 2G network which does not offer fast data transfer rates.
As shown in the figure, the number of users of the faster networks is growing rapidly and the number of 2G users is declining.
Different Types of Networks
In addition to the GSM and 3G/4G transmitters and receivers, smart phones make connections to different types of networks. Some examples of other networks that are used by smart phones include:
- GPS – the Global Positioning System network uses satellites to transmit signals that cover the globe. The smart phone can receive these signals and calculate the phone’s location to an accuracy of within 10 meters.
- Wi-Fi – Wi-Fi transmitters and receivers located within the smart phone enable the phone to connect to local networks and the Internet. In order to receive and send data on a Wi-Fi network, the phone needs to be within the range of the signal from a wireless network access point. Wi-Fi networks are usually privately owned but often provide guest or public access hotspots. A hotspot is an area where Wi-Fi signals are available. Wi-Fi network connections on the phone are similar to the network connections on a laptop computer.
- Bluetooth – A low-power, shorter range wireless technology that is intended to replace wired connectivity for accessories such as speakers, headphones and microphones. Because Bluetooth technology can be used to transmit both data and voice, it can be used to create small local networks.
- NFC – NFC stands for Near Field Communications. NFC is a wireless communication technology that enables data to be exchanged by devices that are in very close proximity to each other, usually less than a few centimeters.