29-06-2012, 04:53 PM
RESOURCE ALLOCATION FOR SECURE OFDMA COMMUNICATION SYSTEMS
ABSTRACT:
We design a resource allocation algorithm for downlink of communication systems supporting real-time (RT) and best-effort (BE) services simultaneously over a time-varying wireless channel. The proposed algorithm aims at maximizing system throughput while satisfying quality of service (QoS) requirements of the RT and BE services. We take two kinds of QoS requirements into account. One is the required average transmission rate for both RT and BE services. The other is the tolerable average absolute deviation of transmission rate (AADTR) just for the RT services, which is used to control the fluctuation in transmission rates and to limit the RT packet delay to a moderate level. We formulate the optimization problem representing the resource allocation under consideration and solve it by using the dual optimization technique and the projection stochastic sub gradient method. Simulation results show that the proposed algorithm well meets the QoS requirements with the high throughput and outperforms the modified largest weighted delay first algorithm that supports similar QoS requirements.
This paper considers the weighted sum rate (WSR) maximized resource allocation (RA) constrained by a system sum power in a downlink transmission system. In particular, two services may cooperate with the source for every relay-aided transmission. The two resource allocation service is proposed to find the globally optimum RA. In the first step, the optimum source/relay power and assisting relays that maximize the rate is found for every combination of subcarrier and destination, assuming a sum power is allocated to the transmission at that subcarrier to that destination in the relay-aided transmission mode and the direct mode, respectively. In the second step, it is designed to find the globally optimum assignment of destination, transmission mode and sum power for each subcarrier to maximize the WSR.
ABSTRACT:
We design a resource allocation algorithm for downlink of communication systems supporting real-time (RT) and best-effort (BE) services simultaneously over a time-varying wireless channel. The proposed algorithm aims at maximizing system throughput while satisfying quality of service (QoS) requirements of the RT and BE services. We take two kinds of QoS requirements into account. One is the required average transmission rate for both RT and BE services. The other is the tolerable average absolute deviation of transmission rate (AADTR) just for the RT services, which is used to control the fluctuation in transmission rates and to limit the RT packet delay to a moderate level. We formulate the optimization problem representing the resource allocation under consideration and solve it by using the dual optimization technique and the projection stochastic sub gradient method. Simulation results show that the proposed algorithm well meets the QoS requirements with the high throughput and outperforms the modified largest weighted delay first algorithm that supports similar QoS requirements.
This paper considers the weighted sum rate (WSR) maximized resource allocation (RA) constrained by a system sum power in a downlink transmission system. In particular, two services may cooperate with the source for every relay-aided transmission. The two resource allocation service is proposed to find the globally optimum RA. In the first step, the optimum source/relay power and assisting relays that maximize the rate is found for every combination of subcarrier and destination, assuming a sum power is allocated to the transmission at that subcarrier to that destination in the relay-aided transmission mode and the direct mode, respectively. In the second step, it is designed to find the globally optimum assignment of destination, transmission mode and sum power for each subcarrier to maximize the WSR.