Data Centric Routing Simulation in Cellular Network

Abstract

Mobile data communication has become a very important and rapidly evolving technology as it allows users to transmit data from remote locations to other remote or fixed locations. Cellular network consists of the network nodes distributed into number of cells. Each cell has an independent fixed base station controlling all the nodes within that cell and all these base stations are controlled by Mobile Switching Station. Each cell has a fixed frequency allocated. Cell can use its frequency only within its boundary. Adjacent cells cannot use the same frequency but cells that are sufficiently far from each other can use the same frequency and thus the frequency is reused in cellular network. This frequency reuse enables cellular network to handle number of connections with limited number channels. Mobile nodes can be anywhere at an instance of time. This mobility of the mobile nodes from one cell to another is observed by its respective base station and control of the moving nodes is handed over to the base station of the new cell. This feature of cellular network is termed as handover. Since the structure of mobile network is very different from the static network, routing in mobile network is under different approach than that of static network. Host centric routing approach focuses on finding short routes between pair of static nodes whereas the data centric routing approach focuses on finding the single destination of required data with no redundancy, from any node in the network. Data centric abstraction middleware is one of the distributed data centric application that abstract a network of mobile nodes as a database where an instance gets some data from another application instance simply by querying the network without knowing where that data is located. In mobile network, the nodes get disconnected frequently due to their mobility; hence they may not be available all the time. So, routing protocols in mobile network are significantly different from traditional routing protocols. To obtain the data from a node in mobile network, no matter where the node is situated, data centric approach is used rather than host centric approach. In data centric approach routing is performed based on data element and not on the nodes in the network. For this a distributed index is maintained, Distributed Hash Table (DHT), and simulation routing is performed over it. DHT is the overlay network protocol. However, the simulation of maintaining the DHT, adding and retrieving the records and other DHT aspects are covered in another dissertation work “Design and Simulation of Distributed Hash Table in Cellular Mobile Network”. To improve the way of routing overlay network is used. The overlay network has no control over how data are routed in the underlying network but it can control the sequence of overlay nodes data traverse before reaching its destination. Computer simulations are invaluable and often unavoidable tool for studying the dynamic behavior and performances of network systems. Networks usually involve a large number of entities (up to millions) each of which having a potentially complex and time-independent (asynchronous) behavior. Discrete-event simulation techniques are well suited for modeling the individual behavior of entities in such networks. Though the network simulator involves assumptions and simplified models that may not reflect in real network system, the majority of routing protocol research has been done in simulation only.