Overview of 2G Technology
2G Technology also called as Second generation wireless communication systems introduced in the year 1990 in Europe. There are two types of system supported in 2G Technology they are:
- CDMA System
- TDMA system
In this technology supports more subscribers due to the introduction of digital switching, introduced data services through SMS later introduced GPRS supporting 9.6 kbps which extended to 115.2 kbps. In spite of digitization 2G still, supports circuit switching for the establishment of a voice call.
GSM Frequency bands
- 890-915 MHz for Uplink and 935-960 MHz for downlink
- 1710-1785 MHz for Uplink and 1805- 1880 MHz for downlink
- For CDMA 824 – 844 MHz for the uplink and 869 – 889 MHz for the downlink
TDMA based 2G Technology
- GSM is a circuit-switched system that divides each 200 kHz channel into eight 25 kHz time-slots. GSM operates on the mobile communication bands 900 MHz and 1800 MHz in most parts of the world. In the US, GSM operates in the bands 850 MHz and 1900 MHz
- GSM owns a market share of more than 70 percent of the world’s digital cellular subscribers.
- GSM makes use of narrowband Time Division Multiple Access (TDMA) techniques for transmitting signals.
- GSM provides basic to advanced voice and data services including roaming service. Roaming is the ability to use your GSM phone number on another GSM network.
- For speech coding or processing, GSM uses Linear Predictive Coding (LPC). This tool compresses the bit rate and gives an estimate of the speech parameters. When the audio signal passes through a filter, it mimics the vocal tract. Here, the encoded speech rate is 13 kbps.
- GSM supports call waiting, Call Conferencing, Call Forwarding, Call Forwarding, Fax, SMS, GPRS, and many other services.
CDMA-based 2G Technology
- IS 95 is the technology that is developed by Qualcomm which uses CDMA
- Here different Walsh codes are used for different subscribers with 1.228 MHz carrier.
Advantages of 2G Technology over 1G
In 2G, some customers or clients can be connected using the same carrier with the use of TDMA in the GSM, in CDMA as possible as 61 channels can be utilized per carrier using different Walsh codes. 2G technology introduced data services in the form of SMS and later provided packet-based service in 2.5G by GPRS and 2.75G by EDGE in GSM and RT-1X in CDMA supporting data rates up to 200 kbps. Low power dissipation in case of GSM hence the battery backup of mobile is more.
- Read it also: Basic information about 4G
International roaming is available in GSM as it is available in GSM Architecture. And IS-95 able to produce a call with reasonable clarity with lowers signal or weak signal.
- Read it also: What is 3G
Most of the technology is patented, and non-standardized, GSM technology interfaces with electronics especially audio amplifiers. Low data speed and hence do not support multimedia and internet services. High data rates are not feasible in GSM.
- Read it also: Long-term Evolution (LTE)
- Read it also: Comparison between 1G, 2G, 3G and 4G wireless technologies