以比例速率限制子載波分配演算法為基礎於正交分頻多重擷取系統之效能改進

Performance Improvement Based on the Subcarrier Allocation Algorithm with Proportional Rate Constraints in OFDMA Systems

廖晟均(Cheng-Jun Liao)

指導教授 ： 曾德樟

國立臺北科技大學/電資學院/電腦與通訊研究所 電子電腦與通訊產業研發碩士專班/碩士(2012年)

摘要

正交分頻多重擷取系統是目前無線通訊系統中所採用的一項重要技術。本論文中提到的資源分配主要是指用戶間的子載波分配與子載波間的功率分配，一種良好的資源分配方法可以有效提升頻譜效益及系統服務品質。目前常用的子載波分配演算法是以比例速率限制子載波分配演算法為主；比例速率限制子載波分配演算法的作法是給予每個用戶速率一定的比例速率限制，以期能符合速率比例常數的用戶間公平性。
本論文是以比例速率限制子載波分配演算法為基礎，分別配合傳統的注水式功率分配演算法與等分式功率分配演算法，提出一效能改善方法。不同於其它子載波分配演算法，本文提出的子載波分配演算法在以等比例常數分配資料子載波個數給每個用戶的程序時，可同時將子載波分配完畢，進而減少其演算法運算所需的時間。相較於其它子載波分配演算法，本文提出的子載波分配演算法雖用戶容量總和稍低，但演算法運算耗時較少，且用戶間的公平性也有較佳的效果。

關鍵字

正交分頻多重擷取 ； 子載波分配功率分配 ； 比例速率限制

並列摘要

Orthogonal Frequency Division Multiplexing Access (OFDMA) is an important technology for wireless communication systems. Resource allocation in OFDMA systems mainly refers to subcarrier allocation among users and power allocation for subcarriers. A suitable resource allocation method can effectively improve the spectral efficiency and the system quality of service (QoS). Subcarrier allocation algorithms with the proportional rate constraint (PRC) are commonly used in the OFDMA systems, which limit the user data rates according to a proportional constant for the fairness among users.
In this thesis we propose a method, based on the subcarrier allocation algorithm with PRC and respectively combined with the water-filling power allocation algorithm and the equal power allocation algorithm, to improve the system performance. Compared with the other subcarrier allocation algorithms, the data subcarriers have been completely allocated in the proposed method, when allocating the number of subcarriers to each user according to the proportional constant.
Computer simulation results show that the proposed method has better performance in terms of the elapsed time for algorithm and the fairness among users than other subcarrier allocation algorithms, although the user sum-capacity is lower.

並列關鍵字

OFDMA ； Subcarrier Allocation ； Power Allocation ； Proportional Rate Constraint (PRC)

參考文獻

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