正交分頻多工存取網路之分段頻率複用機制改善方案

An Enhanced Fractional Frequency Reuse Scheme in OFDMA Networks

黃琬茜(Wan-Chien Huang)

指導教授 ： 涂世雄

中原大學/工學院/電機工程研究所/碩士(2010年)

https://doi.org/10.6840/cycu201000693

摘要

摘要
本篇論文我們提出一個正交分頻多工存取建立在頻率複用裡的機制去改善頻率效益，減少功率以及解決內部細胞間的干擾和訊號路徑衰減影響而提出一個新機制，Enhanced Fractional frequency Reuse(EFFR)。
在我所提出的改善機制中，有幾個主要的重點。第一，我們使用狹窄波束型的方向型天線來減少我的系統功率消耗以及擴大我的細胞傳輸範圍。第二，在改善分數頻率複用機制裡，我們分配在蜂巢式系統細胞中心以及邊緣的使用者使用不同頻段，來達到降低內部細胞間的干擾值。第三，我們來解決細胞邊緣使用者因與基地台距離較遠產生訊號衰減現象。選擇中繼站作為傳輸路徑把衰減效應降到最低。
在這篇論文中，我們將提出以下的貢獻：
（1）我們提高頻率使用效率：在相同頻帶傳輸下,對彼此的干擾是在可容忍範圍內重複使用頻帶。
（2）我們減少錯誤率：利用細胞內部以及鄰近的細胞頻帶的不同，讓之間產生的干擾降低。
(3) 我們平均功率強度：藉由基地台所涵蓋範圍距離遠近的關係，分配不同傳輸功率來降低系統容量的浪費。
最後，我們知道我所提出的方法能改善傳輸效益，減少傳輸功率的浪費及降低錯誤率。

關鍵字

正交分頻多工存取 ； 分段頻率複用 ； 中繼站 ； 方向型天線

並列摘要

Abstract
In this thesis, we propose a scheme of Orthogonal Frequency Division Multiple Access (OFDMA) system based on fractional frequency reuse system to improve the frequency efficiency, reduce power depletion, and solve the problems of inter-cell interference and signal Path-Loss while designing forward new scheme named the Enhanced Fractional Frequency Reuse (EFFR).
This new Enhanced Fractional Frequency Reuse Scheme has several main focuses. At first, we use Narrow-Beam Trisector Cell (NBTC) type of the direction antennas to reduce power consumption of my system and to expand transmission coverage of our cell. Then, the Fractional Frequency Reuse mechanism is used to improve interference issue. At our mechanism, the users in the center area and edge area are distributed with different frequency bands to reduce the inter-cell interference (ICI). Finally, the problem of signal decay between the users in edge area and the base station (BS) will be solved by selecting the relay station (RS) as the transmission path to minimize the Path-Loss effect.
In this thesis, the following contributions are gained:
1. Improve the frequency efficiency: In the same frequency band , the interference towards each other is within tolerable range, and frequency can be reused.
2. Decrease the bit-error-rate: Dividing the inner cells and adjacent cells within the different frequency bands. The interferences between them could be reduced.
3. Average power strength: Weather coverage of base stations (BS) by the distance is far or closed, we allocate the different transmit power to reduce waste of system capacity.
Finally, we know that our propose method can improve the efficiency transmission, reduce the waste of transmission power and decrease the bit-error rate.

並列關鍵字

NBTC ； FFR ； OFDMA ； Relay Station

參考文獻

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[16] Yue Zhao, Xuming Fang, Xiaopeng Hu, Zhengguang Zhao, Yan Long, “Fractional Frequency Reuse Schemes and Performance Evaluation for OFDMA Multi-hop Cellular Networks”, 2009