Fourth Generation (4G) Mobile and Wireless Communications Systems
Fourth-Generation (4G) wireless communications systems have been proposed because of the difficulty of Code Division Multiple Access (CDMA) technologies to achieve higher data rates and therefore, satisfy continuously ever increasing demand for data rates and bandwidth to meet multi-media requirements. With ever increasing in data rates, the output power of the air-interface must be increased and or the size of the cell has to be decreased to accommodate higher data rates. Both of these approaches will present implementation difficulties. 4G communications networks were originally conceived by Defense Advanced Research Projects Agency (DARPA) in US, which selected the distributed architecture, the End-to-End Internet Protocol (IP), and the peer-to-peer networking. Network coverage and capacity is adapting dynamically to accommodate changes in users patterns. Users automatically move away from the congested routes to allow network to dynamically and automatically self-balance itself. The panel discussions will be focused on the 4G capabilities; suggestions will be proposed on network architectures, and the technologies to achieve 4G network goals.
Panelists and Chairs:
Prof. Raouf Boutaba, University of Waterloo, Canada
Prof. Vijay K. Garg, Chung-Ang University, Seoul, Korea
Prof. Tae-Gyu, Chang, Chung-Ang University, Seoul, Korea
Prof. Naser Manochehri, Sultan Qaboos University, Oman
Prof. Nazar Elfadil, Sultan Qaboos University, Oman
Switching Implementation in Optical Network
With the advent of optical technologies, most notably optical networks with wavelength division multiplexed (WDM) transmission having several wavelengths per fiber as channels, produce much interest in solving the huge demand on the internet with ever increasing traffic. Transmission rate of a channel is currently limited to 40 Gbps. Now-a-day the implementation of IP (Internet Protocol) over DWDM are growing and there is a gradual migration from the existing IP over ATM (Asynchronous Transfer Mode) and over SONET (Synchronous Optical Network). With the techniques of MPLS (Multi Protocol Label Switching) and OXC (optical cross connect) IP packets are directly connected to each other into wavelength channels. The signal with O-E-O (optical to electrical and electrical to optical) conversion produces a delay where as the signal without O-E-O reduces delay time and thus produces additional network robustness. Theoretically, the data rates could be pushed somewhere between 25-75 terabits per second. In some networks, IP routers are connected through SONET interfaces and DWDM links. The router and routing techniques with OXC require switches and their implementation. Other than opto-electronic switches, the optical switches are used directly for routing without converting the optical signal to electrical signal. The panel discussions will be focused for different implementation methods of optical switches, such as MEMS, Liquid Crystals, Bubble, waveguide type TO (thermooptic) and EO (electrooptic), etc, and suggestions will be proposed for the technologies according to the specific need of the switches considering their size, capacity, speed, cost and reliability in different WDM systems.
Panel Chair: Professor Dr. Alok Kumar Das, Jadavpur University, Kolkata, India
Last updated: 19 July 05