OFDMA寬頻無線網路下的資源與功率配置方法

Abstract

OFDMA在寬頻無線網路上已經廣泛地被運用，例如LTE及WiMAX. OFDMA可支援多使用者分集技術及功耗調整。 在現有的文獻當中，多數文章在討論如何增進使者的速率以求得系統效能最佳化。然而，高傳輸效能也會導致高功耗。因此，本篇在OFDMA無線網路下，針對上行，來探討資源及功率分配的問題。我們把此問題描述成一個混合整數規劃(mixed integer programming)問題，並希望在所有傳輸需求都被滿足之下，求得最小的功耗。我們顯示這個問題是一個NP-hard的問題，並提出我們的方法來解決。模擬結果顯示，我們的方法可以比其它方法結省最多90%的功耗。

The Orthogonal Frequency Division Multiple Access (OFDMA) technique has been widely applied in broadband wireless networks, such as IEEE 802.16 (WiMAX) and 3GPP Long Term Evolution (LTE). OFDMA can support multiuser diversity and dynamic power allocation. Existing studies have targeted at improving network throughput by increasing the transmission rates of mobile stations (MSs). Nevertheless, this is at the cost of higher energy consumption of MSs. In the paper, we consider the tile-and-energy joint allocation problem for uplink transmissions in an OFDMA wireless network. We formulate this problem as a mixed integer programming, where the objective is to minimize MSs' energy consumption subject to satisfying their demands. We show this to be NP-hard and develop a heuristic taking advantage of the water-filling technique. Simulation results show that our heuristic can save up to 90% of MSs' energy as compared to existing results.