WIRELESS COMMUNICATION : WIRELESS COMMUNICATION M.Saravana Kumar by INTRODUCTION : INTRODUCTION High data rates will be necessary to carry multimedia communications, and hence networks will be asked to deal with a multimedia traffic mix of data, video, and voice packets, each having different transfer requirements.
Scientific research in the wireless multimedia communications field is growing fast: an update and harmonious compendium on the most recent technologies at both radio and network layer is needed. Slide 3: Future telecommunications systems supporting multimedia services have to provide users with access to services from both terrestrial and satellite fixed and mobile networks. Electromagnetic waves- basics of wireless communication : Electromagnetic waves- basics of wireless communication Electromagnetic waves, often referred to as radio waves, are waves of energy that are similar to light waves and travel through the air at the speed of light
A 2.4GHz signal (such as Bluetooth, WiFi, Zigbee or WiMedia) completes a cycle as it travels through the air every 12.5 cm. Electromagnetic Spectrum : Electromagnetic Spectrum What is an Antenna? : What is an Antenna? A transmitting antenna transmits by exciting it at the base (or at a pair of antinodes), while in a receiving antenna, the applied electromagnetic field is distributed throughout the entire length of the antenna to receive the signal.
The induced current will be much higher than if the signal struck a metal object Slide 7: Every antenna has at least one exact resonance point. Note that an antenna also transmits a stronger signal if it is resonant on the frequency used. Evaluation of mobile networks : Evaluation of mobile networks The main achievements in the evolution of mobile networks, moving from second generation (2G) systems towards third generation (3G) through the so-called “evolved” 2G .
The transition from pure circuit-switched (CS) systems to CS-voice/packed data and IP-core-based systems Evolution from 2G to 3G : Evolution from 2G to 3G Evolved Second Generation Systems : Evolved Second Generation Systems The evolution from the first generation (1G) of analog systems meant the passage to a new system.
The success of 2G systems, which extend the traditional Public Switched Telephone Network (PSTN) or Integrated Services Digital Network (ISDN) and allow for nationwide or even worldwide seamless roaming with the same mobile phone, has been enormous. Slide 11: Today’s most successful digital mobile cellular system is Global System for Mobile communications (GSM) with users in more than 174 countries .
The digital market is divided into several systems, time division multiple access (TDMA)-based, code division multiple access (CDMA)-based, and GSM systems. High Speed Circuit-Switched Data : High Speed Circuit-Switched Data High-Speed Circuit-Switched Data(HSCSD) comes from the need to solve problems related to the slowness of GSM in data transmission.
HSCSD can be considered as a first step in the transitional technology between 2G and the packet-mode GPRS AND EDGE : GPRS AND EDGE General Packet Radio Service (GPRS) and Enhanced Data Rates for GSM Evolution (EDGE) have been introduced as transitional data technologies for the evolution of GSM.
The new physical channel is called 52-multiframe and it is composed of two 26 control multiframes of voice-mode GSM.
The 52-multiframe is logically divided into 12 radio blocks of four consecutive frames. Third Generation Systems : Third Generation Systems The evolution from 2G to 3G is characterized by a revolutionary change of focus from voice to mobile multimedia services.
Medium data rate services for file transfer and Internet access at rates on the order of 64 to144 Kbps.
Multimedia services, which provide concurrent video, audio, and data services to support advanced interactive applications. Future Technologies : Future Technologies WLANs
Optical Network Technologies THE FUTURE INTERNET WLANs : WLANs Another important aspect of the evolutionary path of wireless networks is represented by wireless local area network.
the fastest-growing segments of the computer industry.
LANs and mobile computing, thus recalling the attention of equipment manufactures. ks (WLANs). Slide 17: The network concepts are moving from network-centered towards person-centered solutions, introducing the new network paradigm of WPANs. CONCLUSION : CONCLUSION The future wireless multimedia communications will be supporting all multimedia services.
We have to be ready for radical changes in the environment.
In order to cope with all the highlighted challenges, new technical solutions at different levels have been already proposed and others are under investigation. Slide 19: THANK YOU