Everything About Second Generation Networks

In a previous post, we discussed the First Generation Network (1G), which marked the beginning of cellular phone networks.

While 1G network brought about advancements such as direct dialing and the portability of mobile phones, it also had limitations, including susceptibility to interference and large phone sizes.

Fortunately, 2G network addressed many of these setbacks. 2G network brought significant improvements to wireless communication technology by introducing the encoding of analog signals into digital signals for transmission as well as allowing for the transmission of multiple access media beyond just audio signals.

In this article, we will provide a comprehensive overview of the 2G network, including its implementation through network standards, network architecture, and a review of the cellular phones that use this technology.

What is a 2G Network?

2G networks are the second generation of mobile telecommunications technology, which was introduced in the 1990s and utilized the GSM (Global System for Mobile Communications), GPRS (General Packet Radio Service), or EDGE (Enhanced Data Rates for GSM Evolution) network standards to enable the transmission of digital signals wirelessly.

It first begins by encoding the audio or other multimedia data that is in analog form into digital form and then transmitting it from the transmitter to the receiver. With the encoding of analog signals into digital signals, the 2G network provided significant improvements over the previous 1G network, such as enhanced call quality and the ability to transmit multiple access media beyond just voice.

Evolution of the 2G Network

2G network technology emerged in the early 1990s when the International Telecommunication Union-Radiocommunication Sector (ITU-R) developed the Global System for Mobile Communications (GSM) network standard. Afterwards, EDGE and GPRS was developed as enhancement to GSM.

Let go through each of these technologies one-by-one.

1. Global System for Mobile (GSM) | 2G

GSM is a standard for digital cellular networks that was developed in Europe in the 1990s to replace the earlier analog cellular networks. GSM networks use a combination of time-division multiple access (TDMA) and frequency-division multiple access (FDMA) techniques to enable multiple users to share the same frequency band.

In a TDMA system, the available frequency band is divided into time slots, and each user is assigned one or more time slots to transmit their data. Because the time slots are very short (usually around 4.6 milliseconds in GSM), many users can share the same frequency band by transmitting and receiving in different time slots.

In addition to TDMA, GSM also uses FDMA to further divide the frequency band into smaller chunks called carriers. Each carrier is then further divided into time slots, which are assigned to individual users. This allows multiple users to share the same frequency band by transmitting and receiving on different carriers and time slots.

2. General Packet Radio Service (GPRS) | 2.5G

General Packet Radio Service (GPRS) is also referred to as 2.5G technology, as it bridges the gap between 2G and 3G networks. GPRS uses packet-switched technology to transmit data over the cellular network, which is more efficient than circuit-switched technology.

With packet switching, data is transmitted in small packets that are sent and received independently of each other, allowing for more efficient use of network resources.

GPRS enables users to access the internet, send and receive emails, and perform other data-intensive tasks on their mobile devices, in addition to making voice calls and sending text messages.

Just like GSM, GPRS uses both TDMA and FDMA technology to share access to data between users.

3. Enhanced Data Rates for GSM Evolution(EDGE ) | 2.75G

EDGE, often referred to as the “2.75G network,” is a mobile data technology that enhanced the 2G GSM cellular network standard by adding a new modulation scheme, known as 8PSK (8 Phase Shift Keying), to increase data transfer rates. This modulation scheme allows for more bits to be transmitted per symbol, increasing the overall data transfer rate.

One of the main advantages of EDGE is that it allows for faster and more reliable data transfer, enabling users to access more advanced data services such as multimedia messaging, mobile internet browsing, and video streaming.

EDGE is backward compatible with existing GSM networks, which means that it can be used on devices that support both 2G and 2.5G technologies. This helped to promote widespread adoption of EDGE technology, as it did not require extensive infrastructure upgrades.

2g Network Architecture

The architecture of a 2G network is divided into two main parts: the radio access network (RAN) and the core network.

The radio access network is responsible for the transmission of voice and data between the mobile device and the network. It is further divided into two main elements: the base transceiver station (BTS) and the base station controller (BSC).

The base transceiver station is responsible for transmitting and receiving signals to and from the mobile device. Each BTS has a coverage area, which is referred to as a cell. A group of BTSs is controlled by a base station controller, which is responsible for managing the allocation of radio channels and the handover of calls from one cell to another.

The core network provides the backbone for the 2G network and is responsible for the routing of calls and the provision of additional services such as short message service (SMS) and voice mail. The core network is composed of several network elements, including the mobile switching center (MSC), home location register (HLR), visitor location register (VLR), and authentication center (AUC).

The mobile switching center is the central hub of the 2G network and is responsible for call routing and switching functions. The HLR is responsible for storing subscriber information, such as phone numbers and location information, while the VLR stores temporary information about a subscriber when they are roaming in a different network area. The AUC is responsible for authenticating subscribers and ensuring that only authorized users can access the network.

Conclusion

With what we have covered in this post, you have seen the great improvement the 2G network brought to wireless communication technology; it enhanced the digital transmission of data, introduced MMS and SMS, and even improved the network coverage.
In the next post, we will explore 3G networks and 3G phones. We invite you to check it out.