Dynamic Sub-Channel Allocation in OFDMA Systems

Josua Bisuk Mubyarto Purba, Pace University


This research considers a Base Station (BS) subcarrier allocation to each user dynamically to increase total capacity and rates within the constraints on total power, bit error rate and each user’s demand. Previous research on subcarrier allocation usually improves the capacity of the system with fairness as the constraint. Many papers regarding subcarrier allocation use capacity and fairness analysis as their focus. Recently, some papers include user satisfaction analysis on their research. In this paper, we developed easier algorithms of user satisfaction as the focus of dynamic sub-channel allocation algorithm development. We develop our algorithms with user satisfaction as a main factor as well as increasing the capacity of the system. The algorithms are built based on the Least Cost algorithm using Transportation Problem of Linear Programming so it is easier to apply it in a real time implementation. This research creates a quantitative analysis method which is called User Demand Satisfaction Index that is used to calculate the performance of the user oriented algorithms. All of algorithms that are developed in this research were analyzed and their performance was compared with known optimum algorithms from Rhee and Shen. The algorithms analysis includes capacity, capacity gain, Fairness Index and User Demand Satisfaction Index. We also evaluate the performance of the algorithms when the numbers of the users are varied in the system and when the capacities of the system are varied. Our solution increases the capacity of BS significantly with excellent user satisfaction and good fairness. Two of the developed algorithms, Maximum Rate Request and Maximum User Request, are recommended to be used in the real time BS protocol stack software because they have great user demand satisfaction as well as increasing the capacity significantly compared to optimum algorithms. These algorithms, Maximum Rate Request and Maximum User Request, will give better Quality of Service (QoS) for each user that has a different kind of rate than the optimum solution from Rhee and Shen. These algorithms also will run faster in a real time implementation in a BS because they are based on linear operation.

Subject Area

Electrical engineering|Computer science

Recommended Citation

Purba, Josua Bisuk Mubyarto, "Dynamic Sub-Channel Allocation in OFDMA Systems" (2012). ETD Collection for Pace University. AAI3530007.



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