3G and 4G are cellular standards that can be utilized for wireless communication. Cellular standards actually found its significance since the era of 2G or GSM. GSM is the second in the generation of cellular technology history and it stands for Global System for Mobile Communication. It had greater capacity and efficiency compared to the first-generation standard. GSM employed TDMA or Time Division Multiple Access where the frequency bandwidth was divided into unique time slots for different users where the users could share the same channel at their respective time slots.
GSM was a very successful cellular generation but the need for a more efficient and higher data rates, especially in Internet of Things (IoT) applications drove the need for a new system in place. This was achieved by the GPRS or General Packet Radio Service. This was an improvement in the GSM standard and also paved the path for the third-generation standards and hence it is often referred to as 2.5G. It was widely deployed in real-time applications which suited the need for high data volume and high data rates of the IoT applications. The significant developments in the GPRS model provided were
- Speed – It provided a much higher data rate than the GSM. It could provide data rate up to 172 kbps, although practically maximum available was in the range of 15-40 kbps.
- Packet switching – GPRS used packet-switching technology rather than the circuit-switched technology of the GSM. Packet switching concept provided more efficient use of available capacity.
- ‘Always On’ connectivity – Another remarkable feature of GPRS is that it offers an ‘Always On’ capability. For circuit-switched techniques, charges were based on how long the call was made, whereas for the packet-switched charges were based on how much data was carried. So, ‘Always On’ connectivity was possible.
GPRS laid down the foundation of 3G revolutions. 3G standards provided a remarkable increase in speed. It provided various value-added services like live streaming, video chatting, mobile internet access etc. 3G provides a network standard which is compatible with the International Mobile Telecommunications-2000(IMT-2000) defined by the International Telecommunication Union (ITU).
According to this standard, a minimum speed of 2mbit/s for stationary users and 348 Kbit/s for moving users are defined. It also provided features like web-based applications and video and audio files. It could send/receive large emails. More secured communication, TV streaming, large capacities and Broadband capabilities were other distinguishing features. However, the fee for 3G License Services was quite expensive.
The building of 3G infrastructure was quite challenging and it required high bandwidth. All these limitations of 3G technology necessitated for better and cost-effective technology.
4G technology started in the late 2000s. It is meant to provide ‘ultra-broadband’ access for mobile devices. The International Telecommunications Union-Radio communications sector (ITU-R) for a network to be 4G compliant known as the International Mobile Telecommunications Advanced (IMT – Advanced) specification.
4G networks are based on Internet Protocol (IP) packet switching and use Orthogonal Frequency Division Multiple Access or OFDMA. In the OFDMA scheme, multiple access can be given by assigning subsets of sub-carriers to different users. This allows simultaneous data transmission from several users.
4G standards are also referred to as ‘Long Term Evolution’ which aims to offer faster and more reliable mobile broadband for smartphones, tablets, laptops and other devices. Some of the significant advantages of 4g or LTE are
- Speed – It has the potential data rate of 100 Mbps, where WiMAX can achieve and top out at 70 Mbps. It is ten times faster than the 3G network. Clear voice quality over the internet, faster downloading of huge files from the internet, clear streaming of videos are some of its high-speed features.
- Uninterrupted Internet connectivity – It is now possible to stream videos online, or watch a movie on the internet with seamless connectivity and without any disruptions. Users can now enjoy uninterrupted video calling and conferences.
- Coverage range – 4G standards can cover a range of 30 miles and more and also with overlapping network ranges, the users get to experience complete connectivity at all times.
- Security – Safety of data is given due importance in the 4G standards. Corporate businesses can rest assured of their safety of data over the 4G wireless network. Also, mobile users who hold sensitive data on their mobile phones are also safe.
Cellular network and IoT
Cellular network like 3G and 4G can be used to connect IoT devices with the internet by having them piggyback on the same mobile networks as smartphones. Not just limited to 3G and 4G cellular standards, the advent of 5G and cloud technology will even expand the usage and application of cellular network to connect the IoT ‘things’ over the internet.
Now cellular networks are not just limited to connect family or friends, it can now connect any physical object around us – home appliances, consumer electronics, hospital equipment etc. With the use of the cellular network, we don’t need to build any new physical infrastructure to support IoT connectivity. With the 5G on the horizon, cellular IoT can see a new future.
M.Tech (VLSI Design and Embedded system)
BS Abdur Rahman University