4G MOBILE COMMUNICATION Presentation Seminar

[born_for seminars]

WIRELESS COMMUNICATIONS
(4G MOBILE COMMUNICATION)


ABSTRACT:
Today, mobile communications play a central role in the voice/data network arena. With the deployment of mass scale 3G just around the corner, new directions are already being researched. In this paper we address about the 4TH G mobile communications.
The Fourth Generation (4G) Mobile Communications should not focus only on the data-rate increase and new air interface.4G Mobile should instead con-verge the advanced wireless mobile communications and high-speed wireless access systems into an Open Wireless Architecture (OWA) platform which becomes the core of this emerging next generation mobile technology. Based on this OWA model, 4G mobile will deliver the best business cases to the wireless and mobile industries,i.e.cdma2000/WLAN/GPRS 3-in-1 product, WCDMA/OFDM/WLAN 3-in-1 product, etc. Asia-Pacific is the most dynamic market of new generation mobile communications with over $100 Billion businesses in the next decade.
The 4G mobile technology -convergence of wireless mobile and wireless access, will definitely drive this growth. Any single-architecture wireless system, including 3G, HSDPA, WiMax, etc., is a transitional solution only, and will be replaced by open wireless architecture system very soon where various different wireless standards can be integrated and converged on this open platform.
The advent of 4G wireless systems has created many research opportunities. The expectations from 4G are high in terms of data rates, spectral efficiency, mobility and integration. Orthogonal Frequency Division Multiplexing (OFDM) is proving to be a possible multiple access technology to be used in 4G. But OFDM comes with its own challenges like high Peak to Average Ratio, linearity concerns and phase noise. This paper proposes a solution to reduce Peak to Average Ratio by clipping method. ATLAB as used to generate the OFDM signal to prove that clipping does reduce Peak to Average Ratio.

INTRODUCTION:
The first operational cellular communication system was deployed in the Norway in 1981 and was followed by similar systems in the US and UK. These first generation systems provided voice transmissions by using frequencies around 900 MHz and analogue modulation.
The second generation (2G) of the wireless mobile network was based on low-band digital data signaling. The most popular 2G wireless technology is known as Global Systems for Mobile Communications (GSM). The first GSM systems used a 25MHz frequency spectrum in the 900MHz band.
Planning for 3G started in the 1980s. Initial plans focused on multimedia applications such as videoconferencing for mobile phones. When it became clear that the real killer application was the Internet, 3G thinking had to evolve. As personal wireless handsets become more common than fixed telephones, it is
clear that personal wireless Internet access will follow and users will want broadband Internet access wherever they go.

2G 3G 4G



The objective of the 3G was to develop a new protocol and new technologies to further enhance the\mobile experience. In contrast, the new 4G framework to be established will try to accomplish new levels of user experience and multi-service capacity by also integrating all the mobile technologies that exist (e.g.
GSM - Global System for Mobile Communications, GPRS - General Packet Radio Service, IMT-2000 - International Mobile Communications, Wi-Fi - Wireless Fidelity, Bluetooth).In spite of different approaches, each resulting from different visions of the future platform currently under investigation, the main objectives of 4G networks can be stated in the following properties:


• Ubiquity;
• Multi-service platform;
• Low bit cost

To achieve the proposed goals, a very flexible network that aggregates various radio access technologies, must be created. This network must provide high bandwidth, from 50-100 Mbps for high mobility users, to 1Gbps for low mobility users, technologies that permit fast handoffs, an efficient delivery.

Migrating to 4G:
The fact that 4G mobile networks intend to integrate almost every wireless standard already In use, enabling its simultaneous use and interconnection poses many questions not yet answered. The research areas that present key challenges to migrate current systems to 4G are many but can be summarized in the following: Mobile Station, System and Service. [7] To be able to use 4G mobile networks a new type of mobile terminals must be conceived. The terminals to be adopted must adapt seamless to multiple wireless networks, each with different protocols and technologies. Auto reconfiguration will also be needed so that terminals can adapt to the different services available. This adaptation may imply that it must download automatically configuration software from networks in range. Moreover terminals must be able to choose from all the available wireless networks the one to use with a specific service. To do this it must be aware of specifications of all the networks in terms of bandwidth, QoS supported, costs and respect to user preferences. Terminal mobility will be a key factor to the success of 4G networks. Terminals must be able to provide wireless services anytime, everywhere. This implies that roaming between different networks must be automatic and transparent to the user. There are two major issues in terminal mobility, location management and handoff management [7]. Location management deals with tracking user mobility, and handling information about original, current and (if possible) future cells. Moreover it must deal with authentication issues and QoS assurances. Handoff management primary objective is to maintain the communications while the terminal crosses wireless network boundaries. In addition, 4G networks, in opposition to the other mobile generations, must deal with vertical and horizontal handoffs, i.e., a 4G mobile client may move between different types of wireless networks (e.g. GSM and Wi-Fi) and between cells of the same wireless network (e.g. moving between adjacent GSM cells). Furthermore, many of the
Services available in this new mobile generation like videoconference have restrict time constraints and QoS needs that must not be perceptible affected by handoffs. To avoid these problems new algorithms must be researched and a prevision of user mobility will be necessary, so as to avoid broadcasting at the same time to all adjacent antennas what would waste unnecessary resources. Another major problem relates to security, since 4G pretends to join many different types of mobile technologies. As each standard has its own security scheme, the key to 4G systems is to be highly flexible.
Services also pose many questions as 4G users may have different operators to different services and, even if they have the same operator, they can access data using different network technologies. Actual billing using flat rates, time or cost per bit fares, may not be suitable to the new range of services. At the same time it is necessary that the bill is well understood by operator and client. A broker system would be advisable to facilitate the interaction between the user and the different service providers.
Another challenge is to know, at each time, where the user is and how he can be contacted. This is very important to mobility management. A user must be able to be reached wherever he is, no matter the kind of terminal that is being used. This can be achieved in various ways one of the most popular being the use of a mobile-agent infrastructure. In this framework, each user has a unique identifier served by personal mobile agents that make the link from users to Internet.