Figure 1. 1G Model
Mobile communication system has been providing the way to which people communicate, sharing messages and data to each other. These facilities are provided to the user within a very short time period with the latest technologies. The technologies of mobile communication is started from first generation (1G) and reached to the fifth generation (5G). First generation started with providing basic services like mobile voice, second generation supports mobile voice as well as low bit rate data services, third generation started with possible high volume movement of data, which will further be expanded to high speed technologies and high mobility, fourth generation (LTE) is the IP-based mobile system that provides access through a collection of radio interfaces and then 5G mobile communication system with high bandwidth with wide coverage area. The next evolutions 6G and 7G are just concepts for now and research works are being carried out, but they are the future of mobile communication networks. The aim of this work is to empower the community with world class broadband capabilities, establishing a future-proof groundwork for new ideas and opportunities to build on. This survey compares the challenges and issues that are involved in each generation and explains how the improvements have been made successfully in mobile communication from earlier generation to modern generation.
Mobile wireless industry started its technology in the early 1970s. Today, present the era of the communication among people, companies through the mobile wireless communication network. In the last decades mobile communication industry is growing very fast and rapidly. The wireless generation generally define as what changes are made in transmission technology time to time and to its frequency bands and these changes are further th classified as 1G, 2G, 3G, 4G, 5G. The 6 generation (6G) wireless mobile communication networks shall integrate satellites to get global coverage. The global coverage systems have been developing by four courtiers. The Global Position System (GPS) is developing by USA. The COMPASS system is developed by China. The Galileo system is developing by EU, and the GLONASS system is developed by Russia. These independent systems are difficulty for space roaming. The task of 7 generation (7G) wireless mobile communication networks are going to Unite.
The telecommunication field has provided many useful services in last few years. 6 billion people use cell phones, so we are going to analyze the various generations of st th cellular system from 1 generation to 6 generation. Currently, there are four generations in the mobile industry. These are respectively 1G- the first generation, 2G- the second generation, 3G- the third generation, and 4G- the fourth generation. 5G was started from late 2020s and still is under process while 6G is assumed that it will be in the market in 5G after.
The first generation mobile communication system was introduced in the beginning of 1980 and using the analog transmission for speech services. In 1979, the first cellular system in the world became operational by Nippon Telephone and Telegraph (NTT) in Tokyo, Japan. Two years later, the cellular epoch reached Europe. The two most popular analogue systems were Nordic Mobile Telephones (NMT) and Total Access Communication Systems (TACS) [2]. The frequency modulation technique for radio transmission using frequency division multiple access (FDMA) with channel capacity of 30 KHz and frequency band was 824-894 MHz [10], which was based on a technology known as Advance Mobile Phone Service (AMPS) [7]. A 1G model mobile phone is displayed in Figure 1.
Figure 1. 1G Model
T h e r e a r e f e w l imi t a t i o n s i n t h e 1 G M o b i l e Communication. First of all it does not have data service to convert the voice into digital signals. Secondly, Global Roaming Service was not possible, like low capacity, unreliable hand off, Poor Voice Quality because in 1G, the data can be carried by only one channel from source (one caller) to destination (another). This means that the two callers are not able to hear each other simultaneously since the number of calls was limited.
2G denotes the second generation of mobile networks, which were the next stage in the development of mobile communication after 1G. 2G was started at 1980s and completed at 1990s, which were mainly for voice transmission with digital signals and the speed up to 64 kbps. When compared to 1G, 2G was step ahead by providing services, such as short message services, picture message services, and Multi Media Message services (MMS). In 2G, two schemes, such as Time Division Multiple Access (TDMA) and Code Division Multiple Access ( CDMA) were used. TDMA allows for the division of signals into time slots and a special code generated by a CDMA for each user in order to communicate over a multiplex physical channel. GSM (Global System for Mobile Communication) technology enables the mobile subscribers to use the mobile phone connection in different countries of the world to provide better quality and capacity. Figure 2 shows the 2G model GSM Architecture.
Figure 2. 2G Model GSM Architecture
Limitations of 2G:
3G is the third generation of mobile phone standards and technology, superseding 2G, and preceding 4G. It is a CDMA based generation. It is based on the International Telecommunication Union (ITU) family of standards under the International Mobile Telecommunications program, IMT-2000. The 3G activities were initiated in Europe and North America under the respective names IMT0-2000 and CDMA-2000. These were based on wideband direct CDMA (WCDMA) and multi carrier CDMA. Both IMT0-2000 and CDMA-2000 used FDD to support two way transmissions with frequency isolation. There are many 3G technologies, such as W-CDMA,GSM EDGE, UMTS, DECT, WiMax, and CDMA 2000. WCDMA and CDMA 2000 have many similar features. However, a major difference is that WCDMA is backward compatible with GSM networks, while CDMA 2000 is backward compatible with IS-95 networks. The basic feature of 3G Technology is fast data transfer rates. 3G technologies use TDMA and CDMA for the use of value added services like mobile television, GPS (Global Positioning System) and videoconferencing. 3G technology is much flexible, because it is able to support the 5 major radio technologies. These radio technologies operate under CDMA, TDMA, and FDMA. The new mobile broadband networks established two distinct 3G families: rd 3GPP and 3GPP2. The 3 Generation Partnership Project (3GPP) was formed in 1998 to foster deployment of 3G networks that descended from GSM 3GPP technologies evolved as follows:
For augmented bandwidth, multiple mobile applications and clarity of digital signals, 3G (Third Generation Technology) is the gateway. GSM technology was able to transfer circuit switched data over the network. The use of 3G technology is also able to transmit packet switch data efficiently at better and increased bandwidth. 3G mobile technologies proffers more advanced services to mobile users. It can help many multimedia services to function. The spectral efficiency of 3G technology is better than 2G technologies. Figure 3 shows 3G Model and Architecture.
Figure 3. 3G Model and Architecture
4G denotes the fourth generation of mobile communication system which was introduced in the year 2010. 4G is the IP-based mobile system that provides access through a collection of radio interfaces. It has the capability to provide speed of 100 Mbps – 1Gbps and has high QoS (Quality of Service) and security. It also offers various kind of services any time as per user requirements at anywhere [9]. The significant features of 4G technology are videoconferencing, location based services, telemedicine, high security, speed, capacity, and low cost per bit. The term MAGIC indicates in 4G as,
M = mobile multimedia
A = any time any where
G = global mobility support
I = integrated wireless solution
C = customized personal service
4G Wireless technology is combined together with the existing and the proposed wireless network technology (e.g. OFDM, MC-CDMA, LAS-CDMA) in order to avoid the faultless roaming from one technology to another. LTE (Long Term Evolution) and Wi-MAX (Worldwide Interoperability for Microwave Access) technologies are used for fourth generation. Figure 4 shows the 4G Model and Mobile Communication System.
Figure 4. 4G Model and Mobile Communication System
There are few limitations in 4G.
The 5G fifth generation of wireless mobile communication system is the wireless internet network, which is maintained by OFDM, MC-CDMA, LAS-CDMA, UWB, Network-LMDS, and IPv6. The 5G is called as Real world wireless or www worldwide wireless web because it does not require limitations. Physical layer and data link layer defines the wireless technology in 5G. These two layers indicate that the 5G technology is like Open Wireless Architecture (OWA) and the virtual multi-wireless network are also maintained in the 5G technology mobile phones. To perform this, the network layer is sub divided into upper network layer for upper terminal and lower network layer for interface and where all the routing is based in IP addresses and that should be different for each IP network worldwide. The main disadvantage of the 5G technology is higher bit rate. The bit rate is controlled by using Open Control Protocol (OTP) [3]. This OTP is supported by transport layer and session layer in 5G networks. The application layer is for quality of service management over different type of networks. Bidirectional bandwidths, less traffic, equally availability of network across the world, 25 Mbps connectivity speed, data bandwidth higher than 1GB, and low cost are the main features of 5G technology.
The commencement of the concept with the following amazing ultra densification, mm wave and massive MIMO (Multiple Input Multiple Output), the 5G will include massive featuring of very fast communication, more advanced security, SDR security (Software Define Ratio), multiple data transfer path, better cognitive radio, and huge bandwidth. In wireless communication system, this method is used to increase the capacity of channel in radio link using multiple transmit and receive antennas. MIMO has become an important element of wireless communication system standards, including IEEE 802.11ac (WI-FI), WI-MAX (4G), etc. It has been mentioned that MIMO system consist multiple antennas at both the transmitter and receiver. Figure 5 shows major advantages of 5G network in providing a lot of services to end users personalization, terminal and network divergent, intelligence networking and network convergence among other benefits are highlighted.
Figure 5. 5G Model and Architecture 34
The 6G mobile system for the global coverage will integrate 5G wireless mobile system and satellite network. These satellite networks consist of telecommunication satellite network, Earth imaging satellite network, and navigation satellite network. The telecommunication satellite is used for voice, data, internet, and video broadcasting; the earth imaging satellite networks is for weather and environmental information collection; and the navigational satellite network is for Global Positional System (GPS). The four different countries which developed these satellite systems are; the GPS by USA, the COMPASS system developed by China. The Galileo system by EU, and the GLONASS system developed by Russia. Figure 6 shows 6G Model and Architecture.
Figure 6. 6G Model and Architecture
This paper provides a comparison overview of all mobile communication generations from 1G to 5G. Increasing demand of people or users encourages the industries and the researchers to develop new technologies [5] .
This paper represents, great evolution of 1G (First Generation) to 4G yield 5G, and introduction to 5G technologies. The 5G mobile phones will have access to different wireless technologies at the same time and the terminal should be able to combine different flows from different technologies. 5G technology offer high resolution for crazy cell phone users. 5G technology will provide super and perfect utilization of cellular communication in future. We can monitor any place of the world from anywhere, observe space and watch TV channels at HD clarity in our mobile phones without any interruption [4].
This paper also focuses on all preceding generations of mobile communication along with fifth generation technology. The development of the mobile and wireless networks is going towards higher data rates and all-IP principle. Mobile terminals are obtaining more processing power, more memory on board, and longer battery life for the same applications each year [11].
The present technology like 3G, 4G cannot support this hence there is a requirement of developing next generation mobile network which is to be called 5G network. Here the problems like better signal coverage, high data speed greater than 1Kgbps, cognitive in 5G, and other key technologies were discussed [7].
This paper combines the advantage of two technologies; 5G terminal and Cognitive radio terminal, where 5G provides Quality of Service and high data rate whereas Cognitive radio gives flexibility and adaptability to 5G. The existing problem for 5G using cognitive radio like detection of primary user using less amount of energy, removing interference so that primary user and noise can be differentiated easily and better allocation of bandwidth [2].
From the above survey, we have studied the features from 1G to 6G. The problems like the above could be overcome by concepts on 7G.
The 7G will be the most advance generation in mobile communication network. It is like the 6G for global coverage, but it will also define the satellite functions for mobile communication. Figure 7 shows the 7G mobile phone and typical satellite system for global mobile communications across the world. But in 7G, there will be some research on demanding issues like the use of mobile phones from one country to another, because the satellite is also moving in constant speed and in specific orbit, the standards and protocols for cellular to satellite system and for satellite to satellite communication system. The dream of 7G can only be true when all standards and protocols are defined. May be this is possible in next generation after 7G and can be named as 7.5G. There is a better way of direct HD video broadcasting for news gathering purpose likewise. This can be the best solution of cost on lower level users [1, 6, 8, 12] .
Figure 7. 7G Mobile Phone and Typical Satellite System for Global Mobile Communications Across the World
Table 1 compares the features like year, sub year, Data Bandwidth, frequency, Multiplexing, switching, core networks, Handover from 1G to 7G .
Table 1. Comparison of Mobile Generations
Table 2 compares the Standards, Technology, services, requirements, definitions and found that services compare the features from 1G to 7G.
Table 2. Comparison of Mobile Technologies
7G will complete all its weak points then there will be no issue of data capacity coverage and hand-off left behind. At that time there will be only one demand from user which is the cost of a call and services. This issue will again start evolutionary change in standard and technology and will also open new horizons for research. This new revolution in technology for cost of mobile phone call and services will be called as 7.5G or 8G.
The 7G system can be supported by the global navigation satellite system, the telecommunication satellite system, and the earth image satellite system. The operator can instantaneously linked to numerous wireless access technologies and faultlessly move between them. The upcoming technologies has a bright future because it can handle best technologies with reasonable costs that can be easily used by the customers. The upcoming technologies will promote concept of nano core, where all the network operators will be connected to one single core and have one infrastructure, regardless of their access technologies. As in evolution and explosion, many will become extinct, but some will change the world. In 6G the cost of mobile call will be relatively high, but in 7G this problem will be improved and the cost of call will be reduced and lower level user will benefit from it.