Challenges in the Migration to 4G

The approaching 4G (fourth generation) mobile communication systems are projected to solve still-remaining problems of 3G (third generation) systems and to provide a wide variety of new services, from high-quality voice to high-definition video to high-data-rate wireless channels. The term 4G is used broadly to include several types of broadband wireless access communication systems, not only cellular telephone systems. One of the terms used to describe 4G is MAGIC—Mobile multimedia, Anytime anywhere, Global mobility support, Integrated wireless solution, and Customized personal service. As a promise for the future, 4G systems, that is, cellular broadband wireless access systems, have been attracting much interest in the mobile communication arena. The 4G systems not only will support the next generation of mobile service, but also will support the fixed wireless networks.

The mobile communication generations has traversed a long way through different phases of evolution since its birth early in the 1970s. the steady global boom in the number of mobile users each year has periodically spurned the development of more and more sophisticated technologies trying to strike the right chord primarily in terms of provision of seamless global roaming, quality services and
high data rate. today numerous different generation technologies with their individual pros and cons are existing globally. the coming era of 4g systems is foreseeing a potential smooth merger of all these heterogeneous technologies with a natural progression to support seamless cost-effective high data rate global roaming, efficient personalized services, typical user-centric integrated service model, high Qos(quality of service) and overall stable system performance. However, every step in such technological advancements presents huge research challenges. this article aims to focus upon some of these potential challenges along with different proposed feasible and non-feasible solutions in the areas of mobile terminals and users, mobile services, mobile and wireless access networks, and communication, in order to give an in-depth view of the next-generation communication systems.

1.1             Aim of the Seminar

Due to the increase in demand for speed, multimedia support and other resources, the wireless world is looking forward for a new generation technology to replace the third generation. This is where the fourth generation wireless communication comes into play. 4G wireless communication is expected to provide better speed, high capacity, lower cost and IP based services. The main aim of 4G wireless is to replace the current core technology with a single universal technology based on IP. Yet there are several challenges that inhibits the progress of 4G and researchers throughout the world are contributing their ideas to solve these challenges. This project deals with understanding the features and challenges for 4G.

With the rapid development of wireless communication networks, it is expected that fourth-generation mobile systems will be launched within decades. 4G mobile systems focus on seamlessly integrating the existing wireless technologies including GSM, wireless LAN, and Bluetooth. This contrasts with 3G, which merely focuses on developing new standards and hardware. 4G systems supports comprehensive and personalized services, providing stable system performance and quality service. However, migrating current systems to 4G presents enormous challenges. In this article, these challenges are discussed under the headings of networks and services, software systems and wireless access.

Recent activity in 4G (fourth generation) mobile communication systems has steeped the race in its implementation at the earliest. 4G wireless being an upcoming standard witnesses burgeoning interest amongst researchers and vendor. It is being designed to allow seamless integration and communication between wireless devices across diverse wireless standards as well as broadband networks wirelessly. Access to different radio technologies is facilitated due to IP-based-4G mobile communication system connecting the user. This paper attempts to make an assessment in development, transition, and roadmap for fourth generation mobile communication system with a perspective of wireless convergence domain and future research issues.

1.2             Motivation of Seminar

The wireless communication filed is a very fast growing area with the number of users and their demand for better resources increasing day by day. The R&D departments of many companies are working on a future technology that can meet these demands at a lower cost.3G is necessary but not sufficient for the demands today. So the world is taking its leap towards the fourth generation wireless communication that promises to bring an end to most of the problems faced. 4G wireless is expected to be launched by 2010, but there are numerous challenges faced by researchers in achieving the desired features. Most of the ongoing researches are in the area of distributed computing, mobile agents, multimedia support etc. Some other research area is to improve the Quality of Service from the viewpoint of both the user and service providers. 4G wireless infrastructures are expected to be deployed in an environment where many other types of wireless and wired communication systems already exist.

1.3             Literature Survey

To fulfill the objectives of the seminar, understanding the concept of 4G is very essential. Several standard books were referred.1. B G Evans & K Baughan, Visions of 4G, IEE Electronics and Communications engineering Journal, Autumn/Winter 2000.2. S Y Hui & K H Yeung, Challenges in the Migration to 4G Mobile Systems, IEEE Commuications, vol 41, no 12, Dec 2003, pp 54-59. 3.R Eijk, J Brok, J Bemmel & B Busropan, Access Network selection in a 4G Environment and the Roles of Terminal and Service Platform, Project: 4GPLUS, Wireless World Research Forum. 4.M Calisti, T Lozza & D Greenwood, An Agent- Based Middleware for Adaptive Roaming in Wireless Networks, Workshop on Agents for Ubiquitous Computing, AAMAS 2004, 20 July 2004, New York, USA. 5.K Murray, R Mathur & D Pesch, Network Access and Handover Control in Heterogeneous Wireless Networks for Smart Apace Environments, 1st International Workshop on Managing Ubiquitous Communications and Services (MUCS), Dec 11, 2003, Waterford, Ireland. 6.F Daneshgaran, M Laddamoda & M Mondin, On the Reconfigurability of a Software Radio Terminal for Supporting the Third and Fourth generation Wireless Standards, IEEE International Conference on Third Generation Wireless and Beyond, June 2001, San Francisco. 7.T H Le & A H Aghvami, Performance of an Accessing and Allocation Scheme for the Download Channel in Software Radio, Proc IEEE Wireless Commun and Net Conf, vol 2, pp 517-21, 2000.

1.4             Applications

• Virtual Presence: This means that 4G provides user services at all times, even if the user is off-site.

• Virtual navigation: 4G provides users with virtual navigation through which a user can access a database of the streets, buildings etc of large cities. This requires high speed data transmission.

• Tele-Medicine: 4G will support remote health monitoring of patients. A user need not go to the hospital and can get videoconference assistance for a doctor at anytime and anywhere.

• Tele-geo processing applications: This is a combination of GIS (Geographical Information System) and GPS (Global Positioning System) in which a user can get the location by querying.

• Crisis management: Natural disasters can cause break down in communication systems. In today’s world it might take days or weeks to restore the system. But in 4G it is expected to restore such crisis issues in a few hours.

• Education: For people who are interested in life long education, 4G provides a good opportunity. People anywhere in the world can continue their education online in a cost effective manner.

1.5             Organization of the Seminar Report

This paper is organized as follows. Chapter 1 provides information such as aim of the seminar, motivation, literature survey and applications.  Chapter 2 provides a brief review of the previous generations, limitations of 3G, problems of 4G. Chapter 3 gives the information about the desired features, objectives and the general view of 4G. Chapter 4 provides a brief review of the research challenges faced by 4G. and finally chapter 5 gives the conclusion. This paper is divided into four sections: introduction, history, features, overview of the potential research challenges and conclusions..

HISTORY

2.1 Brief History of Generations

 The history and evolution of mobile service from the 1G (first generation) to fourth generation are discussed in this section. Table 1 presents a short history of mobile telephone technologies. This process began with the designs in the 1970s that have become known as 1G. The earliest systems were implemented based on analog technology and the basic cellular structure of mobile communication. Many fundamental problems were solved by these early systems. Numerous incompatible analog systems were placed in service around the world during the 1980s.The 2G (second generation) systems designed in the 1980s were still used mainly for voice applications but were based on digital technology, including digital signal processing techniques. These 2G systems provided circuit-switched data communication services at a low speed. The competitive rush to design and implement digital systems led again to a variety of different and incompatible standards such as GSM (global system mobile), mainly in Europe; TDMA (time division multiple access) (IS-54/IS-136) in the U.S.; PDC (personal digital cellular) in Japan; and CDMA (code division multiple access) (IS-95), another U.S. system. These systems operate nationwide or internationally and are today's mainstream systems, although the data rate for users in
these system is very limited. During the 1990s, two organizations worked to define the next, or 3G, mobile system, which would eliminate previous incompatibilities and become a truly global system. The 3G system would have higher quality voice channels, as well as broadband data capabilities, up to 2 Mbps. Unfortunately, the two groups could not reconcile their differences, and this decade will see the introduction of two mobile standards for 3G. In addition, China is on the verge of implementing a third 3G system. An interim step is being taken between 2G and 3G, the 2.5G. It is basically an enhancement of the two major 2G technologies to provide increased capacity on the 2G RF (radio frequency) channels and to introduce higher throughput for data service, up to 384 kbps. A very important aspect of 2.5G is that the data channels are optimized for packet data, which introduces access to the Internet from mobile devices, whether telephone, PDA (personal digital assistant), or laptop. However, the demand for higher access speed multimedia communication in today's society, which greatly depends on computer communication in digital format, seems unlimited. According to the historical indication of a generation revolution occurring once a decade, the present appears to be the right time to begin the research on a 4G mobile communication system. 

First Generation: 1G was based on analog technology and basically intended for analog phones. It was launched in the early 1980s. It introduced the first basic framework for mobile communications like the basic architecture, frequency multiplexing, roaming concept etc. Access technology used was AMPS (Advances Mobile Phone Service).

Second Generation: 2G was a revolution that marked the switching of mobile communication technology from analog to digital. It was introduced in the late 1980s and

it adopted digital signal processing techniques. GSM was one of the main attractive sides of 2G and it introduced the concept of SIM (Subscriber Identity Module) cards. Main access technologies were CDMA (Code Division Multiple Access) and GSM (Global System for Mobile Communication).

2.5 Generation: 2.5 G was basically an extension of 2G with packet switching incorporated to 2G. It implemented hybrid communication which connected the internet to mobile communications.

Third Generation: The basic idea of 3G is to deploy new systems with new services instead of just provide higher bandwidth and data rate. Support for multimedia transmission is another striking feature of 3G. It employs both circuit switching and packet switching strategies. The main access technologies are CDMA (Code Division Multiple Access), WCDMA (Wideband CDMA), and TS- SDMA (Time division Synchronous CDMA).

2.2 Limitations of 3G

4G is being developed to accommodate the QoS and rate requirements set by forthcoming applications like wireless broadband access, Multimedia Messaging Service (MMS), video chat, mobile TV, HDTV content, Digital Video Broadcasting (DVB), minimal services like voice and data, and other services that utilize bandwidth.

The 4G working group has defined the following as objectives of the 4G wireless communication standard:

• A spectrally efficient system (in bits/s/Hz and bits/s/Hz/site).
• High network capacity: more simultaneous users per cell.
• A nominal data rate of 100 Mbit/s while the client physically moves at high speeds relative to the station, and 1 Gbit/s while client and station are in relatively fixed positions as defined by the ITU-R.
• A data rate of at least 100 Mbit/s between any two points in the world.
• Smooth handoff across heterogeneous networks.
• Seamless connectivity and global roaming across multiple networks.
• High quality of service for next generation multimedia support (real time audio, high speed data, HDTV video content, mobile TV, etc).
• Interoperability with existing wireless standards and
• An all IP, packet switched network.

In summary, the 4G system should dynamically share and utilize network resources to meet the minimal requirements of all the 4G enabled users.

CONCLUSION

As the history of mobile communications shows, attempts have been made to reduce a number of technologies to a single global standard. Projected 4G
systems offer this promise of a standard that can be embraced worldwide through its key concept of integration. Future wireless networks will need to support diverse IP multimedia applications to allow sharing of resources among multiple users. There must be a low complexity of implementation and an efficient means of negotiation between the end users and the wireless infrastructure. The fourth generation promises to fulfill the goal of PCC (personal computing and communication)—a vision that affordably provides high data rates everywhere over a wireless network.

4G seems to be a very promising generation of wireless communication that will change the people’s life in the wireless world. There are many striking attractive features proposed for 4G which ensures a very high data rate, global roaming etc. New ideas are being introduced by researchers throughout the world, but new ideas introduce new challenges. There are several issues yet to be solved like incorporating the mobile world to the IP based core network, efficient billing system, smooth hand off mechanisms etc. 4G is expected to be launched by 2010 and the world is looking forward for the most intelligent technology that would connect the entire globe.