4G – The Next Generation Wireless NetworksDipesh Handa, Parag Goswami

dipeshhanda@yahoo.com

9990011402, 9990073809

Electronics and Communication Engineering, Final Year

G. B. Pant Government Engineering College

New Delhi

Abstract— Mobile Telecommunications is the assisted transmission of signals over a distance for the purpose of communication to or from a mobile device or user.4G (Fourth Generation) is basically a wireless standard with an aim to provide services like Video Calling, HD Video Streaming and other Wireless Broadband Services at an ultra-broadband speed to mobile as well as to the stationary users. 4G will be capable of providing Data Rates of 100 Mbit/s and 1 Gbit/s speeds both indoors and outdoors environments respectively, with premium quality and high data security. It is a successor to the technologies like 2G and 3G.The main concept behind the 4G Networks is to make the whole network IP Based. It will interoperate with the pre-existing Wireless Technologies and it aims at seamlessly integrating the existing technologies like GSM, CDMA, Wireless LAN and Bluetooth.

I. INTRODUCTION

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. It is a successor to 2G and 3G standards, with the aim to provide a wide range of data rates up to ultra-broadband (gigabit-speed) Internet access to mobile as well as stationary users. A 4G cellular system must have target peak data rates of up to approximately 100 Mbit/s for high mobility such as mobile access and up to approximately 1 Gbit/s for low mobility such as nomadic/local wireless access, according to the International Telecommunication Union (ITU) requirements. A 4G system is expected to provide a comprehensive and secure all-IP based Network.

A 4G system will be able to provide a comprehensive IP solution where voice, data and streamed multimedia can be given to users on an "Anytime, Anywhere" basis, and at higher data rates than previous generations. As the Second generation was a total replacement of the First generation networks and handsets; and the Third generation was a total replacement of Second generation networks and handsets; so too the Fourth generation cannot be an incremental evolution of current 3G technologies, but rather the total replacement of

the current 3G networks and handsets. Fourth generation networks are likely to use a combination of WiMAX and WiFi.

II. GENERATIONS OF MOBILE SYSTEMS

The flowing are the Generations that lead to the Wireless Mobile Evolution:

A. First Generation (1G):

1G System was an Ana log System developed in 1970’s.It brought twp major achievements i.e. in the field of microprocessors and the digitalization of the control link.

B. Second Generation (2G):

2G System was Digital in nature. This new Digital System gave a better voice quality and higher Data Rats.

C. Third Generation (3G):

3G System is also digital in nature and provided services at a much faster rates starting from around 380 Kbps to 2 Mbps.

D. Fourth Generation (4G): The Current Scenario

4G System will implement a whole IP based Integrated Network. Will also give high data rates as compared to pre –existing technologies.

III. OBJECTIVES OF 4G NETWORKS

4G System is being developed to accommodate the QoS (Quality of Service) and rate requirements set by further development of existing 3G applications like wireless broadband access, Multimedia Messaging Service (MMS), Video Chat, Mobile TV, but also new services like HDTV (High Definition Television) content, minimal services like voice and data, and other services that utilize bandwidth. It may be allowed roaming with wireless local area networks, and be combined with digital video broadcasting systems.

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

1) To implement a fully IP based Integrated System of Systems and Network of Networks.

2) To provide relatively higher data rates to Multimedia Services as compared with the pre existing technologies.

3) Seamless Connectivity and Global Roaming across multiple wireless and mobile networks.

4) High Quality of Service (QoS) for next generation multimedia support (real time audio, high speed data, HDTV video content, mobile TV, etc).

5) To provide information anywhere, anytime, with a seamless connection to a wide range of users, and receiving a large volume of information, data, pictures, video, and so on, are the keys of the 4G infrastructures. Based on the developing trends of mobile communication, 4G System is working to provide broader bandwidth, higher data rates, and Smoother and Quicker Handoffs.

6) Interoperability with the existing networks.

IV. ARCHITECTURE

The 4G Network will be a network of networks in which a large number of networks are interconnected with each other through a common IP based Core. A 4G system will interoperate with the existing technologies like 2G, 3G and other Wireless Technologies.

Fig. Architecture of 4G System

V. WHY MOVE TOWARDS 4G?

4G (Fourth Generation Communication) basically came into demand because of the requirements that are not met by the predecessor generations. Some of the key factors responsible for the evolution of 4G communication network are:

1) Difficulty of CDMA to provide higher data rates.

2) Need for continuously increased data rates and bandwidths to meet the multimedia requirements. Basically Wider Bandwidths are needed for data streaming, full motion video and for Wireless Teleconferencing.

3) To provide seamless transport of the signals between different networks.

4) Inability to roam between different wireless networks i.e.4G provides roaming stability.

VI. COMPARISION WITH PRE - EXISTING TECHNOLOGY

A comparison of the existing 3G Technology is made with 4G Technology so as to point out the differences that lead to the development of 4G Networks.

TABLE I3G VS 4G

No. Attribute 3G 4G1

Network Architecture

Wide Area Cell Based

Hybrid-Integration of WLAN, Bluetooth, WiMAX, WiBRO

2Component Design

Optimized Antenna Systems

Smart Antenna Systems

3Bandwidth

5MHz – 20 MHz

Up to 100 MHz

4Data Rate

380Kbps – 2Mbps

Up to 1Gbps

5 Technology UsedCDMA, CDMA 2000

OFDM

VII. CHALLENGING ISSUES

The following issues must be solved for the implementation of the future 4G networks:

A. Network Discovery And Selection:

The 4G System should automatically discover the wireless systems connected together by processing the signals by those devices.

Proposed Solution:User or System initiated discoveries, with automatic

download of Software modules for different Wireless Systems.

B. Terminal Mobility:

To locate and update the locations of the Terminals in various Wireless Systems. Also to perform Horizontal and Vertical Handoffs as required with minimum Handover Latency and Packet Loss.

Proposed Solution: Fast Signalling Schemes and Fast Handoff Mechanisms are being proposed shortly.

C. To Support Global Roaming:

One of the major Challenges occurs for the deployment of 4G Networks is how to support Global Roaming when the user moves from One Wireless System to another (Eg: Cellular Network to Satellite Network and vice versa)

Proposed Solution:The Following 4G Network Architectures are proposed as

follows:1) Multimode Device Architecture2) Overlay Network Architecture3) Common Access Protocol Architecture

D. Quality of Service (QoS):

Quality of Service (QoS) refers to resource reservation control mechanisms rather than the achieved service quality. Quality of service is the ability to provide different priority to different applications, users, or data flows, or to guarantee a certain level of performance to a data flow.

One of the most difficult problems that are to be solved, when it comes to IP mobility, is how to insure the constant QoS level during the handover:

1) Depending on whether the new access router is in the same or some other sub network, we recognize the horizontal and vertical handover.

2) However, the mobile terminal can not receive IP packets while the process of handover is finished. This time is called the Handover Latency.

3) Mobile IPv6 has been proposed to reduce the handover latency and the number of lost packets.

E. Handoff Delay:

It is another important Challenging Issue in 4G Networks. Delay can be problematic in Internetwork Handoffs because of the following Restrictions:

1) Authentication Procedures are required for Message Exchange, Database Access and Negotiation – Renegotiation due to the significant difference between the needed available QoS Requirements.

2) During Handoff Process the user may experience drop in QoS.

Proposed Solution:Deploying Priority based Algorithms and using Location Awareness Adaptive Applications can reduce both Handoff Delay and QoS Variability.

VIII. TECHNOLOGIES USED

The following Technologies are required for the implementation of 4G Networks:

A. Orthogonal Frequency Division Multiplexing (OFDM):

1) Orthogonal frequency-division multiplexing (OFDM), essentially identical to coded OFDM (COFDM) and discrete multi-tone modulation (DMT), is a frequency-division multiplexing (FDM) scheme utilized as a digital multi-carrier modulation method. A large number of closely-spaced orthogonal sub-carriers are used to carry data. The data is divided into several parallel data streams or channels, one for each sub-carrier. Each sub-carrier is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase-shift keying) at a low symbol rate.

Fig. Block Diagram of OFDM

2) Facilitates Single Frequency Networks (SFNs); i.e., transmitter Macrodiversity

3) Robust against Intersymbol Interference (ISI) and fading caused by multipath propagation.

B. Advanced Antenna Systems (Smart Antennas):

1) A Smart Antenna (or Intelligent Antenna) system combines multiple antenna elements with a signal-processing capability to optimize its radiation and/or reception pattern automatically in response to the signal environment. Example of Smart Antenna is MIMO System.

2) MIMO is a smart antenna system where “smartness” is considered at the receiver’s end as well as at the transmitter’s end Apart from this, the reliability in transmitting high speed data in the fading channel can be improved by using more antennas at the transmitter or at the receiver. This is called transmit or receive diversity.

Fig. Advanced Antenna Systems (Smart Antennas)

C. Internet Protocol Version 6 (IPv6):

1) It has a Larger Address Space as compared to IPv4.

2) IPv6 support is essential in order to support a large number of wireless-enabled devices. By increasing the number of IP addresses, IPv6 removes the need for Network Address Translation (NAT)

3) IPv6 System would further reduce the cost to the Service Providers because of the low cost Equipments used in this Technology.

IX. ADVANTAGES

4G Systems provides the Advantages to Users and Operators as follows:

A. Users:

1) Access to broadband multimedia services with lower cost and wherever mostly needed. This is basically known as PERSONAL MOBILITY. Personal Mobility mainly concentrates on the movements of the users instead of user’s terminal and involves the provision of personal communication and personalized operating environments.

2) Inter network roaming.

B. Operators:

1) Lower Cost Of Network and Equipments.2) Higher Capacity and QoS Enhancement.3) They will offer customers a range of new

broadband and multimedia services in vehicular environments.

C. Wireless System Discovery:

1) A multimode terminal attaches to WLAN and scan the available systems.

2) It can download software needed by the user automatically and manually.

X. APPLICATIONS

The following are the Applications of 4G Networks:

A. Virtual Presence:

It provides Users to access the information even if the user is at Off – Site environments.

B. Virtual Navigation:

It provides Users to access the Database of Streets, Buildings etc.

C. Tele – Geo Processing:

This is a combination of Geographical Information System (GIS) and Global Positioning System (GPS) in which user can access his location at that instant.

D. Multimedia Video Services:

It will provide a wide range of Multimedia Services at high data rates even in the vehicular environments. It basically provides services like Bursting and Streaming.

XI. CONCLUSIONS

1) 4G network environment will be an inter-working environment of various access networks (such as 2G, 3G, WLAN, WiMax/WiBro, ad-hoc & satellite) with IP Based core.

2) Multimedia traffic will be dominant in the future. It is estimated that voice would contribute to only 20-30 % of total traffic in the future.

3) A modified IP will be the universal network layer protocol in the future.

4) The entire network would be digital and packet switched.

5) The work on 4G systems has begun in the industry as well the academia.Ex:- Wireless World Research Forum (WWRF) has Ericsson, Alcatel, Nokia and Siemens AG. The National Science Foundation (NSF) has announced a program in 1999 that calls for proposals that would look at issues involved in 4G systems.

ACKNOWLEDGMENT

I am Indebted to Mrs. Monika Garg, the Senior Professor Electronics and Communication Engineering division G. B. Pant Government Engineering College New Delhi and other faculty members for giving me an opportunity to learn and present this paper. I am also very grateful to my team member for the completion of this paper. I once again extend my sincere thanks to all of them.

REFERENCES

[1] 4G Wireless Systems website [Online] Available: http://www.nd.edu/~mhaenggi/NET/wireless/4G[2] (2002) The IEEE website. [Online] Available: http://www.ieee.org/[3] The IEEE Communications Society Website [Online] Available: http://www.comsoc.org/index.html[4] 3GPP TS 23.107 v.5.9.0, “Quality of Service (QoS) Concept and

Architecture,” June 2003.[5] Suk Yu Hui “Challenges in the Migration to 4G Mobile Systems” City

University of Hong Kong.[6] Upkar Varshney and Radhika Jain “ Issues Emerging in 4G Systems “

Georgia State University