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Cellular Teletraffic This article is one of a group being considered for deletion in accordance with Wikipedia's deletion policy. Please see the policy discussion page of the votes for deletion list for details. This request is being discussed to form a consensus whether this is, or could be, an article appropriate for Wikipedia. If you feel deletion is not justified by Wikipedia deletion policy you may vote against its deletion. Please do not remove this notice or blank this article while the question is being considered. However, you are welcome to continue editing this article, especially if you can address the concerns of those who believe the article should be deleted. Should you do so, please remark on the policy discussion page regarding its improvement. The concept of cells The concept of cellular radio can be illustrated by means of a diagram fig. 1.0. An area to be supplied with radio service is divided into cells. Each of these cells as shown in fig. 1.0 is assigned a range of frequencies (f1-f6) and they each have corresponding Radio Base Stations. The group of frequencies can be reused in other cells bearing in mind that it is not reused in adjacent cells as that will cause co-channel interference. See fig.1.0 which illustrate the reuse of frequency ranges(f1-f6) such that co-channel interference is minimal. cells may vary in radius in the ranges (1 km to 30 km). The shape of the cells shown in fig.1.0 is hexagonal, but in practice in practice the shape of the cell can be circular or some other undefined irregular shapes. the boundaries of the cells can also overlaps between adjacent cells 1. Structure of the cellular network A simple structure of the cellular mobile-radio network is shown in figure 1.1. RBS : Radio base station
MSC : Mobile-service switching cenntre
PSTN: Public switched telephone network
The diagram in fig 1.1 taken from the book by Flood 1 summarises how the concept of cells together with mobile network equipment is used to provide a cellular network for mobile station (MS) and PSTN users. This network is the foundation the GSM system network. There are many functions that are performed by this network in order to make sure telephone customers get the desired service, some of them are : Mobility management, registration, call set up, cell handover process, etc. Any MS connects to the network via an RBS in the corresponding cell which in turn connects to the MSC. The MSC allows the connection of other networks apart from moible networks. The link from an MS to the RBS is called an uplink while that from an RBS to the MS is termed downlink. Traffic load and cell size The more traffic we have the more base stations will be neede to service the customers. In order to meet a demand of service it should be noted that the number of base station for a simple network, will be proportional to the number of cells. The engineer can achieve the goal of supplying the increasing population of customers by increasing the number of cells in the area concerned, so that this will also inrease the number of base stations. This seems like a logical solution but it cannot be practical from the cost point of view. A method called cell splitting has been seen as the most effect way of providing services to a large population. this simply works by dividing the cells already present into smaller sizes hence increasing the number of cells. This will mean that the cell size has to be reduced and it is limited by the system through considering cost/benefit implications. Reduction of the cell radius to accommodate extra loads of traffic is known to give an optimal solution to traffic load, Walke 3, emphasises that. References 1 J. E. Flood. Telecommunicattions Networks. Institution of Electrical Engineers, London, UK, 1997. chapter 12. 2 P. Key, D. Smith. Teletraffic Engineering in a competetive world. Elsevier Science B.V., Amsterdam Netherlands, 1999. Chapter 1 (Plenary) and 3 (mobile). 3 Bernhard H. Walke. Mobile Radio Networks: Networking, protocols and traffic perfomance. John Wiley and Sons, LTD West Sussex England, 2002. Chapter 2.
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