OFDMA_Part36

# OFDMA_Part36 - approximation of the power-rate function,...

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36 4.1.2.2 Simulation Of Select Margin Adaptive Resource Allocation Algorithms I chose the following two MA algorithms to simulate in MATLAB: BABS+ACG and BABS+RCG [32]. The purpose of doing the simulations is to gather some experience in writing a MA resource allocation algorithm. I tried to set the parameter values close to the values described in the paper’s simulation. The average rate per subcarrier, R max , was set to 7.81kbps. The total number of subcarriers was 128. There were 10% video users, 40% voice users and 50% data users. Each video user, voice user and data user used 64, 16, and 30 kbps respectively. I wrote MATLAB code that ordered the users randomly to increase the fairness for the algorithm. Although the paper uses the Saleh Valenzuela multipath fading channel model, I decided to use the 6-Ray Rayleigh channel model because I understood it well. Also, I used [32]’s
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Unformatted text preview: approximation of the power-rate function, i.e. f ( r ) = 0.6r 3 . In our simulation, I compared BABS+ACG with BABS+RCG. Although stage 1 was the same for both algorithms, stage 2 differed and gave us interesting results. As can be seen in Figure 17 and Figure 18, our results were inline with the results in [32]. In Figure 17, BABS+RCG uses slightly less transmission power on average as compared to BABS+ACG. This is because some of the constraints (explained in the previous section) were more relaxed in case of BABS+ACG and hence it suffers a slight performance hit. However, relaxed constraints allow BABS+ACG to run much faster than BABS+RCG (shown in Figure 18). The difference in execution times becomes large as the number of users K increases. This is a good example of the performance vs. simplicity tradeoff. ACG trades some performance to achieve considerably lower complexity....
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## This note was uploaded on 09/27/2009 for the course ECE 399 taught by Professor Prof during the Spring '09 term at University of Texas at Austin.

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