Wi-Fi & Bluetooth
- Bluetooth is a wireless communication technology that allows devices to be connected within a maximum range of about 30 meters
- Before communication can happen, two devices connect using a process called “pairing” to establish a secure connection
- When two devices pair, they both exchange a cryptographic key. Both these keys are used to generate a secret shared key which is used to encrypt the data between the two devices and create a Wireless Personal Area Network (WPAN)
- Bluetooth operates using a frequency range of around 2.4Ghz
- Connected devices continuously change their transmitting frequency between 79 different channels to avoid interference and improve the reliability of the connection. This is known as the frequency hopping spread spectrum (FHSS)
- Bluetooth may be preferred over Wi-Fi when:
- File transfer required between two close-range devices such as a laptop and smartphone without the need for internet connectivity
- Streaming audio from a smartphone to another wireless device such as a speaker or headphones
- Connecting to a car system allows for music streaming and hands-free calling
- When low power communication is required
- Wi-Fi is also a wireless communication technology that allows devices to be connected up to a range of about 100 meters depending on the standard that is being used
- Wi-Fi operates across the 2.4Ghz and 5Ghz frequency ranges and although 5Ghz is faster, the 2.4 GHz range is preferred as the lower frequencies often travel further and penetrate obstacles more easily
- Similar to Bluetooth bands are split into channels
- Wi-Fi-enabled devices connect to a network by connecting to a hotspot or wireless access point (WAP) also referred to as an access point (AP)
- Wi-Fi may be preferred over Bluetooth when:
- High speed data transfer is required
- Long range communication is required
- Many devices are needed to be connected at the same time
Similarities between Bluetooth and Wi-FI
- Use radio waves for wireless technologies
- Can connect multiple devices
- Support encryption for secure connections
- Based on industry standards that are universally accepted
- It can be used to connect Internet of Things (IoT) devices and applications
Differences between Bluetooth and -Wi-Fi
|
|
|
|
|
Maximum number of connections |
7 |
30 (based on a standard consumer grade router with high end options providing substantially more) |
|
Transmission frequency |
2.4Ghz |
2.4Ghz, 5Ghz |
|
Maximum range (meters) |
30 meters |
100 meters (depending on obstructions) |
|
Maximum transfer speed (Depending on the standard being used) |
3 Mbytes / Sec |
75 Mbytes / Sec |
Worked example
A school IT team is trying to determine what technology they should use to connect students' tablets around the school for data transfer and are unsure whether to choose Wi-Fi or Bluetooth technology. Consider the advantages and limitations of both and justify your answer
[7]
WiFi offers significantly faster transfer rates compared to Bluetooth [1]
so students will be able to upload and download files faster [1]
WiFi coverage can be over a much larger area compared to Bluetooth [1]
so that students will be able to access resources wherever they are in the school [1]
Bluetooth however, is easy to set up [1]
students can transfer data without the school having to invest in expensive infrastructure [1]
Given the current situation, the school is in, the preferred choice for connecting student's tablets would be Wi-Fi [1]
