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Tham khảo tài liệu 'cellular networks positioning performance analysis reliability part 7', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 7 Numerical Approach to Performance Analysis of Multi-Parametric CAC in Multi-Service Wireless Networks Agassi Melikov1 and Mehriban Fattakhova2 institute of Cybernetics National Academy of Sciences of Azerbaijan 2National Aviation Academy of Azerbaijan Azerbaijan 1. Introduction Cellular wireless network CWN consists of radio access points called base stations BS each covering certain geographic area. With the distance power of radio signals fade away fading or attenuation of signal occurs which makes possible to use same frequencies over several cells but in order to avoid interference this process must be carefully planned. For better use of frequency recourse existing carrier frequencies are grouped and number of cells in which this group of frequencies is used defines so called frequency reuse factor. Therefore in densely populated areas with large number of mobile subscribers MS small dimensioned cells micro-cells and pico-cells are to be used because of limitations of volumes and frequency reuse factor. In connection with limitation of transmission spectrum in CWN problems of allocation of common spectrum among cells are very important. Unit of wireless spectrum necessary for serving single user is called channel for instance time slots in TDMA are considered as channels . There are three solutions for channels allocation problem Fixed Channel Allocation FCA Dynamic Channel Allocation DCA and Hybrid Channel Allocation HCA . Advantages and disadvantage of each of these are well known. At the same time owing to realization simplicity FCA scheme is widely used in existing cellular networks. In this paper models with FCA schemes are considered. Quality of service QoS in the certain cell with FCA scheme could be improved by using the effective call admission control CAC strategies for the heterogeneous traffics e.g. see 1 3 . Use of such access strategy doesn t require much resource therefore this method could be considered operative and more defensible for .
