INFORMATION PAPER International Journal of Recent Trends in Engineering, Vol. 1, No. 2, May 2009 287 Optimization of Co-channel Interference Ratio (CCIR) for Omni-Directional Antenna in Mobile Computing Santosh Kumar 1* , S. C. Sharma 2 , Sandip Vijay 3 , Shahnawaz Husain 4 1, 2 Research Scholar, Electronics and Computer Discipline, DPT , IIT, Roorkee, Saharanpur Campus, Saharanpur, India. 2 Associate Professor, Electronics and Computer Discipline, DPT , IIT, Roorkee, Saharanpur Campus, Saharanpur, India. 4 M.Tech. (CSE-Student), Graphic Era Institute of Technology, Dehradun, India Abstract Due to the insufficiency of available bandwidth and the continuously growing demand for cellular communication services, there are many cells using same frequency band. All the cell using the same channel are physically located apart by at least reused distance, even though the power level is controlled carefully so that such “co-channels” do not create a problem for each other, there is still some degree of interference due to non-zero signal strength of such cells .This paper simulate the co-channel interference ratio (CCIR) for mobile station at the various distance from BS and shows, as the path loss propagation increases, the value of CCIR increases exponentially and achieved a fabulous result and also simulate, for the same value of path loss propagation & varying distance results shows that CCIR decreases linearly. In this paper, two tier model is used for simulating the result. Simulation is done for 1-Tier, although there are negligible interference between focused cell and 2-Tier of CCIR cells over same frequency band. Keywords:-1-Tier & 2-Tier same band frequency cell, Reuse Distance, co-channel Interference, Path loss propagation. 1. Introduction In current scenario there are tremendous increases in the demand of cellular phone but insufficiency of available frequency bands have forced to reuse the same frequency channel for the different BS; it introduces the concept of reuse distance for reducing the co-channel interference. If we discuss the strategy of 2-Tier system in mobile system then we need to know that the CCIR is negligible but still non- zero. The system working scenario will be discussed later. In this paper results confined that what will be the CCIR exactly for the MS at various distances for the serving BS in 1-Tier. In this paper section 2 describes formation of cluster and reuse distance, section 3 describes proposed mathematical formulation, section 4 describes results simulation and comparison and finally section 5 describes conclusion and discussion. 2. Formation of cluster and Reuse Distance Reused distance defined as the distance between the two cells using the same channel. It is denoted by D. There is a close relationship between the reuse distance D, radius of cell R and the number of cells N of a cluster i.e D=√3N R so reuse factor will be, D/R=√3N. The number of cells, N per cluster is given by N= i 2 +ij+j 2 , here i denotes the number of cells along the direction i from center of a cell and j denotes number of cells at 60 0 to the direction of i and the value of N will be 1,3,4,7,9,12,13,16……..[1]. Figure 1: Finding the center of adjacent cluster using integer i & j 3. Proposed Mathematical formulation We know that D=√(3*N) R where N is no of Cells per cluster, R is radius of hexagon. The value of N can be calculated from the formulae [1]. © 2009 ACADEMY PUBLISHER