Woo-Geun Ahn

Proportional fair scheduling in relay enhanced cellular OFDMA systems

We propose an efficient proportional fair (PF) scheduling algorithm for multi-user OFDMA systems employing fixed relays. An PF metric maximization problem is first formulated for relay enhanced OFDMA cellular systems. A two-step algorithm is then proposed to solve the problem; the user routing step and the resource allocation step. The simulation results confirm the near-optimal performance of the proposed algorithm in PF sense.

An improved ranging algorithm for ad-hoc relay networks over IEEE 802.16 OFDMA systems

We present a novel ranging scheme with a specific notification code to reduce the complexity of ranging detection while providing a sufficient ranging opportunity for small ranging success time (RST) in ad-hoc relay (AHR) networks over IEEE 802.16 OFDMA systems. Computational complexity and RST are analyzed. The simulation results show that the proposed scheme outperforms the conventional one and can be a good choice for ranging protocol in battery-powered AHR networks.