Sung-Oh Kwon

Energy-Efficient SINR-Based Routing for Multihop Wireless Networks

In this paper, we develop an energy-efficient routing scheme that takes into account the interference created by existing flows in the network. The routing scheme chooses a route such that the network expends the minimum energy satisfying with the minimum constraints of flows. Unlike previous works, we explicitly study the impact of routing a new flow on the energy consumption of the network. Under certain assumptions on how links are scheduled, we can show that our proposed algorithm is asymptotically (in time) optimal in terms of minimizing the average energy consumption. We also develop a distributed version of the algorithm. Our algorithm automatically detours around a congested area in the network, which helps mitigate network congestion and improve overall network performance. Using simulations, we show that the routes chosen by our algorithm (centralized and distributed) are more energy efficient than the state of the art.

Delay-aware call admission control algorithm in 3GPP LTE system

Long Term Evolution (LTE) has being standardized by the 3rd Generation Partnership Project (3GPP) as the evolution of WCDMA. Different from the conventional mobile communication technologies that deliver voice traffic through circuit switched networks, in LTE, all kinds of traffic are transferred through packet switched networks based on Internet Protocol (IP). In order to provide Quality of Service (QoS) in packet switched networks, Radio Resource Management (RRM) is very important. Especially, Call Admission Control (CAC), which is a part of RRM, plays an important role in RRM because it can prevent network congestion and guarantee certain level of QoS for on-going calls by accepting or rejecting service requests. In this paper, we propose delay-aware CAC algorithm in order to provide QoS for various kinds of services in LTE system. Delay-aware CAC algorithm utilizes statistical datas for packet delay and PRB utilization in order to guarantee packet delay requirements for on-going calls. In order to evaluate performance of delay-aware CAC algorithm, we perform simulations under various environments. The simulation results show that the delay-aware CAC algorithm can satisfy packet delay requirements for various service types defined in LTE specification.

A Resource-Estimated Call Admission Control Algorithm in 3GPP LTE System

As the evolution of high speed downlink packet access (HSDPA), long-term evolution (LTE) has being standardized by the 3rd generation partnership project (3GPP). In the existing mobile communication networks, voice traffic is delivered through circuit-switched networks, but to the contrary in LTE, all kinds of traffic are transferred through packet-switched networks based on IP. In order to provide quality of service (QoS) in wireless networks, radio resource management (RRM) is very important. To reduce network congestion and guarantee certain level of QoS for on-going calls, call admission control (CAC), in part of RRM, accepts or rejects service requests. In this paper, we proposed resource-estimated CAC algorithm and evaluated the performance of the proposed CAC algorithm. The result shows that the proposed algorithm can maximize PRB utilization and guarantee certain level of QoS.