電力線通信系統(tǒng)中的子載波組分配

摘 要:研究電力線通信系統(tǒng)在各種約束下的速率自適應(yīng)子載波分配模型，提出一種基于層次分析法的動態(tài)子載波組分配算法。為了對比還提出以一種不含決策者偏好信息和比特功率比最大化的逐子載波分配算法。在典型電力線信道環(huán)境下還仿真以一個子載波為一組的子載波組分配算法，結(jié)果表明一子載波一組的子載波組分配算法性能最優(yōu)，但其復(fù)雜度最大，而動態(tài)子載波組分配算法的性能與逐子載波分配對比算法的性能相當(dāng)，且接近于一子載波一組的分配算法，復(fù)雜度大大減少。

關(guān)鍵詞: 電力線通信; 子載波組分配; 層次分析; 優(yōu)先因子

中圖分類號:TP913 文獻(xiàn)標(biāo)識碼:A

文章編號:1004-373X(2010)11-0065-06

Subcarrier-band Allocation for Power-line Communication System

FANG Yong-jun1， XU Zhi-qiang2

(1.Department of Assets Administrant， University of South China， Hengyang 421001， China;

2. Department of Electric and Electron Engineering， North China Electric Power University， Beijing 102206， China)

Abstract:A dynamic subcarrier-band allocation algorithm based on analytic hierarchy process is proposed by researching a rate adaptive subcarrier allocation model for power-line communication systems under the various restrictions. A subcarrier by subcarrier allocation algorithm without the determinist′s preferential information and with the maximal bit to power ratio is also proposed for the comparison. The proposed algorithms and the subcarrier-band algorithm with only one subcarrier are tested in typical power-line channel scenarios， and the simulation results show that the performances of subcarrier-band algorithm with only one subcarrier are best but for its maximum complication， the performances of proposed subcarrier-band dynamic allocation algorithm with lowest complication are similar to the subcarrier by subcarrier algorithm and adjacent to the sub-carrier-band algorithm with only one subcarrier.

Keywords: power-line communication; subcarrier allocation; analytic hierarchy; priority factor

0 引 言

正交頻分復(fù)用(Orthogonal Frequency Division Multiplexing，OFDM)技術(shù)是實現(xiàn)電力線高速通信的最具競爭力的技術(shù)。但是電力線信道具有時變性和頻選性，噪聲和干擾功率都較高，傳輸多用戶信號且衰減嚴(yán)重[1]，如果使用傳統(tǒng)的OFDM技術(shù)，將難以保證系統(tǒng)的服務(wù)質(zhì)量。自適應(yīng)OFDM技術(shù)根據(jù)每個用戶子載波對的信噪比，動態(tài)地為每個用戶分配子載波和每個子載波上的比特數(shù)及發(fā)射功率，能夠有效降低惡劣信道特性對數(shù)據(jù)傳輸?shù)挠绊懀虼藢⒍嘤脩糇赃m應(yīng)OFDM技術(shù)應(yīng)用于電力線通信中，可以有效提高系統(tǒng)的頻帶利用率和服務(wù)質(zhì)量[2]。

實現(xiàn)多用戶自適應(yīng)OFDM技術(shù)的關(guān)鍵之一是子載波、比特和功率的分配。在子載波分配確定后，可由比特分配確定功率分配或由功率分配確定比特分配，但不能由比特分配和功率分配確定子載波分配。……