Cellular

Sirindhorn International Institute of Technology Thammasat University School of Information, Computer and hold forth Technology ECS 445: Mobile Communications The Cellular Concept Prapun Suksompong, Ph.D. prapun@siit.tu.ac.th November 22, 2009 This feel covers fundamental cellular receiving set concepts which are at the karyon of providing wireless dialogue service to subscribers on the move victimisation deposited radio spectrum. Contents 1 Cellular Teleph integrity organizations 2 Frequency use 3 Cell planing with hexagonal cells 4 Co-Channel Interference 5 Trunking 6 Improving Coverage and capableness 1 4 7 10 13 14 1 Cellular Telephone remainss 1.1. receiving set telephone system should be structured to achieve high school talent with destineed radio spectrum while at the uniform magazine covering very large areas. 1 1.2. Older System: Achieve a large coverage area by using a simple, high powered transmitter. ? Put BS on top of mountain s or tall towers, so that it could promote coverage for a large area. The next BS was so far away that interference was not an issue. Severely limit the number of users that could communicate coincidentally. Noise-limited system with few users.

The Bell quick system in New York City in the mid-seventies could only support a maximum of twelve cooccurring calls over a thousand square miles. 1.3. The number of concurrent calls a mobile wireless system can raise up is essentially determined by the total spectral shop allocation for that system and the heapwidth required for transmitting signals used in treatment a call. Example 1.4. Using a typical running(a) system, each ch annel needs to have a halowidth of some 2! 5 kHz to enable su?cient audio quality to be carried, as well as allowing for a guard band between adjacent signals to ensure there are no undue levels of interference. Using this concept, it is possible to accommodate only forty users in a frequency band 1-MHz wide. Even if one C MHz were allocated to the system, this would enable only 4000 users...If you want to stick a full essay, order it on our website: OrderEssay.net

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