![]() ![]() For a specific geographic area, if clusters are replicated M times, then total number of channels – system capacity = M x T – Choice of K determines distance between cells using the same frequencies – termed co-channel cells – K depends on how much interference can be tolerated by mobile stations and path loss TI - 1011.Let T = total number of duplex channels K cells = size of cell cluster (typically 4, 7,12, 21) N = T/K = number of channels per cell.Need to track user to route incoming call/message TI - 1011.Handoffs between cells must be supported.Increases system capacity with frequency reuse – Drawbacks:.Cellular concept - small cells with frequency reuse – Advantages.Why not a large radio tower and large service area? – Number of simultaneous users would be very limited (to total number of traffic channels T) – Mobile handset would have greater power requirement.Cluster of cells K = group of adjacent cells which use all of the systems frequency assignment TI - 1011.The multiple access techniques translates F to T traffic channels.Frequency assignment of F MHz for the system.Approximate cell coverage with a hexagon - allows easier.Propagation models represent cell as a circular area.Increase system capacity by frequency reuse.Often approximate coverage area of a cell by a idealized hexagon. ![]() Neighboring cells do not use same set of frequencies to prevent interference.Geographic Service divided into smaller “cells”.Shahryar Saleem Assistant Professor Department of Telecom Engineering University of Engineering and Technology Taxila TI - 1011 TI - 1011 Cellular Mobile Communication SystemsLecture 6 Engr. ![]()
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