Mobile phone technology is linked to our daily lives. The mobile phone has given us the independence to communicate with each other regardless of place, city and country, and the backbone of this is mobile phone technology. A mobile phone is owned by three out of four people in this world. This growth of mobile technology is tremendous.
There are many technologies in use in mobile communication. They are like GSM (Global System for Mobile Communication), CDMA (Code Division Multiple Access), EDGE (Enhanced Data Rate for GSM Evolution) to UMTS (Universal Mobile Telecommunications System) or W-CDMA (Wireless Multiple Access). wideband code division) and CDMAOne (IS-95) to CDMA 2000 1X, EV-DV and mobile TV technologies such as Media FLO, DMB and DVB-H.
GSM (Global System for Mobile Communication) is the most widely used mobile communication technology in the world. This technology gives us the advantage of using the mobile communication service throughout the world through roaming. One of its advantages to become popular is interoperability.
Originally, the letters were the abbreviation for the words Group Special Mobile, but as it becomes hugely popular, the meaning of the words also radically changes and now stands for Global System for Mobile Communications. GSM technology was first used in the year 1991 and is rapidly increasing due to some of its unique advantages. Now the total number of GSM subscribers in the world is around 3 billion and this number is constantly increasing.
GSM System Overview:
GSM technology is the 2G (second generation) mobile communication technology. The goal was to serve a large number of subscribers and increase channel capacity and provide the advantage of interoperability that did not exist in the previous analog system (first generation system). GSM achieved this by using a multiplexing technique called TDMA (Time Division Multiple Access). By adopting this, it was possible to accommodate a large number of users on limited bandwidth by increasing channel capacity. In addition to this encryption was added to encrypt the voice in the communication medium. The previous system was not as secure, and anyone could trace the voice data through a receiver.
Basic GSM services:
Voice communication is the basic service provided by GSM. To provide this service in GSM, the voice data is first encrypted and then decrypted by a speech encrypting device. As the voice service is the basic service in GSM, apart from this GSM system also provides other services. Although their quality is as good as 3G service, they are still popular where 3G service is not yet available. GSM supports data speeds of up to 9.6 kbps, teletext and text to voice, and other value-added services.
One service provided by GSM that is hugely popular and taken advantage of by people from all walks of life is the Short Message Service (SMS). Previously this was developed for GSM only but after that other mobile technologies also adopted it and it is successfully used in all technologies. This service has become popular in all mobile phone services, particularly young people like this because the cost is low and this service provides alphanumeric messaging, forwarding, two-way messaging, etc.
GSM technology basics:
GSM technology uses 200 KHZ RF frequency channels. In this technology, each operator is divided into eight operators to give access to eight users in one operator. This is called time division multiplexing. That is why it is called a TDMA (Time Division Multiple Access) system.
The BTS (Base Transceiver Station) are located in a small group BSC (Base Switching Center) which controls a group of Base Transceiver Stations, one MSC (Mobile Switching Center) controls all these BSCs. Along with this there are two other devices HLR (Home Location Record) and VLR (Visitor Location Record) which tracks the location of the mobile.
EDGE:
The evolution of GSM is EDGE. The EDGE data implementation can be transferred up to a speed of 384 kbps. In some cases, it is also called EGPRS (Enhanced General Packet Radio Service System). This system can be called as 2. 5G system. GSM uses the least Gaussian shift key for data transfer, but EDGE uses 8 PSKs, which significantly increases the data rate.
GSM EDGE basics:
GSM EDGE cellular technology is an upgrade of existing GSM network technology. This can be implemented in the existing GSM network by installing software.
CDMA1x2000 technology:
CDMA1X2000 is the upgrade of the original IS-95 CDMA one system. CDMA has a number of evolutions of which CDMA1X2000 is the first.
The purpose of this CDMA1X200 is to provide a migration path from the existing original CDMA. This format is the basic 3G standard.
The first change made to CDMA1X200 was to the Walsh Code which was initially 64 bit on CDMAone and is now being changed to 128 bit. Another code name, turbo code, was introduced in this technology to detect the error more efficiently.
In CDMAone a form of QPSK was used where the data in the I and Q channels were the same but in CDMA1X2000 the data in the Q and I channels are different. So half the bandwidth can be used for the same number of chips, or in other words, twice as many chips can be sent over the same bandwidth.
So the CDMA1XX2000 has provided efficient spectral efficiency and also improves throughput and the data rate is significantly high.
3G HSPA or High Speed Packet Access:
3G HSPA or High Speed Packet Access technology is a technology that is a combination of two technologies, one is uplink and one is downlink which can be built on top of the existing 3G-UMTS or W-CDMA. technology to provide higher data transfer speeds in data transmission.
16 QAM is used in the downlink to increase the data rate. Here, channel sharing brings great efficiency and also integrates with IP and packet data concepts.
3G LTE or 3G LONG-TERM EVOLUTION:
To compete with high data speed services like WiMax, work on the next generation of cellular technology has already started and has also been implemented in some cases.
The third generation partnership project working on the development of UMTS 3G began its evolutionary work with a workshop held in Toronto, Canada in November 2004.
The goal of LTE is to get up to 100 Mbps download speed and 50 Mbps upload speed on each 20 Mhz spectrum. LTE is also required to serve 200 active users in each 5MHz cell.
The basic work of 3G LTE is already done by 3GPP and the infrastructure improvement task is also going in parallel.