الفهرس 
Introduction to mobile communication systemOnly 14 pages are availabe for public view
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Abstract
The prevalence of Land Mobile Radio (LMR) systems can be seen throughout the world, in both the public and private sectors. Consumers heavily utilize wireless radio technology such as Citizen Band radio and the Family Radio Service. However, the main use of LMR spectrum is by business and government entities wishing to maintain efficient, reliable communication among their employees. From small companies dispatching technicians on service calls to large emergency agencies coordinating volunteers and relief efforts in a disaster, both businesses and the public at large have benefited from wireless radio in the form of Land Mobile Radio. One significant user of LMR spectrum is the law enforcement community. Officers and agents find the coordination and instantaneous communication capabilities of a LMR radio invaluable. From routine status checks to situational awareness and covert lifelines, law enforcement entities rely on their radios to get or send information right when it is needed. It is not surprising then that the usefulness of LMR has brought about an abundance of system deployments. Each new deployment brings additional spectrum requirements. These new systems are typically placed in the VHF and UHF bands. However, ever increasing demands for spectrum from many types of wireless service have prompted several changes to frequency allocations to relieve the congestion. Research objectives The objective of this study is to investigate the downlink performance of Land Mobile Radio. The objective of this study is to provide some techniques to enhance Land Mobile Radio and maintain good GoS, QoS for different data rates which support wide range of applications such that voice. On the other hand this study aims to evaluate the blocking probability, and how to predict the path loss at different parameters. The research aims to study and analyze how to calculate the GoS for different channels, and increase the system performance. The research concludes the system performances increased by increasing the system area through number of cells. Finally the research recommends to apply a plan to increase the performance.