Cellular

Sirindhorn International Institute of Technology Thammasat University School of Information, Computer and discourse Technology ECS 445: Mobile Communications The Cellular Concept Prapun Suksompong, Ph.D. prapun@siit.tu.ac.th November 22, 2009 This melodic phrase covers fundamental cellular receiving set concepts which are at the burden of providing wireless dialogue service to subscribers on the move victimization deposited radio spectrum. Contents 1 Cellular Teleph adept organizations 2 Frequency use 3 Cell planing with hexagonal cells 4 Co-Channel Interference 5 Trunking 6 Improving Coverage and efficacy 1 4 7 10 13 14 1 Cellular Telephone clays 1.1. receiving set telephone administration should be structured to achieve high school readiness with bourned radio spectrum while at the uniform date 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 moun tains or tall towers, so that it could bring in 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 synchronally. Noise-limited system with few users.

The Bell officious 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 synchronal calls a mobile wireless system can articulatio is essentially determined by the total spectral storehouse allocation for that system and the heapwidth required for transmitting signals used in treatment a call. Example 1.4. Using a common running(a) system, each channel needs to have a resoun! dwidth of close 25 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 twoscore 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 by a full essay, order it on our website: OrderEssay.net

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