The time is when the telecommunication engineers are overwhelmed by a number of theoretical concepts and prospects of their implementation. At the same time, they also find themselves unequipped to analyze networks unless idelized to a great extent, and often unrealistically. Truely, the field of telecommunication has become inter-disciplinary. A network designer has hence to be aware of a broad spectrum of disciplines. Below we describe briefly the topics of research in our laboratory:

Multiple Access System: In this system, a number of users are interconected by a channel or a number of channels. The channel resources are common to all users. ALOHA system has been the parsadigm of a multiple access system for low and bursty traffic loads. When a user transmits his message over an ALOHA channel, his transmission is successful only if other users do not transmit their messages over the same channel while his message transmission is in progress. Though, conceptually, this scheme is readily understandable and easily implementable, it shows surprisingly complex behavor patterns and there have been many investigations to characterize them. Our laboratory has modelled these behavior patterns from structural point of view of the system,. We have also conveived of some new miltiple access strategies by which the performance of ALOHA schemes can be increased. Also, our research has included the analysis of heterogeneous ALOHA systems.

Broadband ISDN: Essentially a technology of the future, our research efforts are directed towards realization of suitable switching schemes. The Broadband ISDN will be based on the Assynchronous Transfer Mode(ATM). We study ATM switch architectures suitable for high capacity and high performance ATM switching. One characteristic feature that distinguishes the B-ISDN switches is their multicast capabality. Our research efforts are directed to achieve very large but modular multicast switch structures.

Intelligent Networks: Another network of the future, the intellegent network is the realisation of networks adaptable to diverse traffic patterns. We realize an intellegent network scheme by rule-based control.

Global Networks based on LEO Satellites: Today, international satellite communication networks are built around geo-stationary satellites. In order to reduce the cost of realizing such networks, recently Low Earth Orbiting Satellites ( called LEO satellites ) have been proposed. In this scheme, the backbone network is built around number of low cost satellites swarming around the Earth, much like the electrons around a nucleus. According to the Industry's prediction, the first network of this kind will be commercially launched by 1997. Our research activites on these schemes include examination of suitable orbit-arrangements and on-board processing requirements.

Mobile Communication Networks: The Demand Assignment Scheme is a widely used implementation in realizing Mobile Satellite Systems(MSS). In this area, we have proposed a promising channel collision resolution scheme called the Parallel Collision Resolution Scheme. Under this scheme, a number of ALOHA channels are available to a user who first reserves the required channel resources before the actual transmission of his messages starts. If the message encounters a collision, the collision is resolved over a group of channels. The advantage of the new scheme is that the channel throughput can be increased and the channel delay can be reduced, when compared with a single channel ALOHA scheme.

Congestion Control: Our research topics related to these issnes include modelling and performance evaluation of networking schemes and their control strategies. These topics include terrestrial networks as well as satellite networks, circiut switched networks as well as packet switched networks. We study the fundamental behavioral issues in the networks with and without control.

Communication as a Social Science: In the technology driven scenario of communication networks, how are the users going to interact among themselves ? Can the basic function of networking a group of users can be abstracted and the transactions interpreted from epistemological point of view ? What are the conditions that a network transaction among many users ultimately converges towareds an agreement or a concensus ? Under what circumstances would it be chaos ? Issues like this are to be studied by communication theorist, social scientist, communication technologist, psychologist and philosopher, all together. We attempt to model such an situation from a new way which we are now developing.