science education
S. Shirvani Moghadam; M. Jalali; H. Aminollahi
Abstract
In this paper, we first simulate ML, MUSIC, Root-MUSIC algorithms and space smoothing in noisy and fiddling environments, and then these algorithms are compared in terms of estimating the accuracy of the angles received from the two sources. By presenting the simulation results of four algorithms in ...
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In this paper, we first simulate ML, MUSIC, Root-MUSIC algorithms and space smoothing in noisy and fiddling environments, and then these algorithms are compared in terms of estimating the accuracy of the angles received from the two sources. By presenting the simulation results of four algorithms in the form of tables that are based on mean, deviation from mean, variance of estimated angles and the percentage of successful experiments, it is observed that Root-MUSIC and MUSIC algorithms in terms of estimation and Detecting close angles is more accurate. In these two methods, the angles close to each other, up to about one degree, can be detected and separated. In addition, simulation results show that spatial smoothing algorithm is the most effective way to identify coherent resources.
Architecture
V. Tabataba Vakili; S. Shirvani Moghaddam
Abstract
In this paper, in order to modify and improve the handoff process, which contains initiation and execution phases, three new prioritization schemes have been investigated. These new schemes prioritize handoff requests considering both traffic and propagation conditions. According to suggested schemes, ...
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In this paper, in order to modify and improve the handoff process, which contains initiation and execution phases, three new prioritization schemes have been investigated. These new schemes prioritize handoff requests considering both traffic and propagation conditions. According to suggested schemes, priority of different candidate base-stations is based on three measurements in a joint state. These measurements are received power at mobile unit, power variation rates, and the number of free traffic channels of adjacent base-stations. Simulation results show that considering similar conditions, i.e. equal number of handoffs, lower call dropping (outage) and smaller delay distance will be achieved by new prioritization schemes rather than previous works. It means access to lower forced termination probability and interference and hence better QoS (Quality of Service). Finally, due to the best trade offs between propagation and traffic criteria, simulation results introduce SPBPS3 as optimum scheme.
Architecture
S. Shirvani Moghadam; H. Noor Alizade; A.H. Khodadadi
Abstract
For cellular mobile users, forced disconnection of a conversation is more undesirable than blocking and rejecting initial communication requests. Various traffic prioritization schemes seek to reduce the forced disconnection of conversations that require channel replacement.In this paper, while reviewing ...
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For cellular mobile users, forced disconnection of a conversation is more undesirable than blocking and rejecting initial communication requests. Various traffic prioritization schemes seek to reduce the forced disconnection of conversations that require channel replacement.In this paper, while reviewing and presenting conventional methods without prioritization, with FIFO and MBPS queuing, with a reserved channel and a combination with queuing and reserved channel, a mobile cellular telecommunication system is considered by considering two types of initial requests and in Now, the connection needs to be replaced, the simulation has been simulated and the results of simulating different methods have been extracted according to the conventional evaluation criteria "probability of forced disconnection" and "probability of blockages" and a comparison has been made between these methods. The results of simulations presented in this study show that the MBPS queuing method is better than the FIFO method and these two methods, while having the possibility of optimal traffic jams, have a much lower probability of forced disconnection than the non-prioritized method.The combined method works better than the reserved channel method because it has the advantages of the reserved channel method and does not have long queues. The results of this study will be useful in selecting the appropriate method and considering the key parameters of each method such as the length of the queue in the queuing methods and the number of channels reserved in the methods based on the reserved channel.
