多輸入多輸出正交分頻多工系統利用隱藏馬式可夫通道模型之適應性傳輸機制

Utilizing Hidden Markov Channel Model for Adaptive Transmission Scheme in MIMO-OFDM Systems

徐文俊(Wen-Jun Shiu)

指導教授 ： 林信標

國立臺北科技大學/電資學院/電腦與通訊研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00373

摘要

現代人的生活對於傳輸速率與傳輸品質要求甚高，但是由於無線通訊環境的複雜性，不同環境對於傳輸的品質與傳輸的速率有不同影響，所以要在不同的環境維持一定的傳輸速率與品質為未來無線通訊發展的重要議題。
本論文將考慮不同的多輸入多輸出架構於不同的通道環，且在可能造成傳輸效能損失的情況下，提出一種以萊斯通道 參數來代表通道品質指標，並利用此 參數的大小對傳輸的調變、通道編碼還有多輸入多輸出架構進行適應性的切換，使得傳輸時可以在能接受的錯誤率範圍內達到最高的資料吞吐量。然而在一般時變的通道環境中，當基地台收到使用者的切換要求並進行適應性傳輸的時候，使用者當下的通道環境可能已經改變，進而造成適應性切換的不準確。所以本論文利用隱藏馬可夫模型的特性，根據所量測的高鐵通道特徵在類似的通道環境下進行資料比對，使得基地台在收到使用者切換要求時能以預測此通道環境之後衰減的狀況下進行預測式的適應性切換，藉此來提升整體適應性切換的準確性。
根據以上的陳述方式，當使用不同的多輸入多輸出架構搭配正交分頻多工系統在不同的通道 參數時，頻譜效益之間會有3 bps/Hz的差別，利用這些不同的通道 參數進行適應性的切換，最高的資料吞吐量能達到75Mbps。而當我們將適應性切換模擬在高鐵通道環境下時，使用隱藏式馬可夫模型來進行通道預測的適應性傳輸在資料吞吐量方面會比沒有進行預測的適應性傳輸平均多了5 Mbps。

關鍵字

多輸入多輸出 ； 萊斯通道K參數 ； 通道品質指標 ； 隱藏馬可夫模型 ； 正交分頻多工

並列摘要

Modern people request transmission rate and transmission quality very much. But, as a result of wireless communication environment is very complicated. So, different environment need to hold transmission rate and transmission quality is very important issue for future wireless communication development.
This paper consider different multiple input multiple output(MIMO) structure in different channel environment, we present one method which according to Rician Channel -factor to represent channel quality indicator(CQI) and utilizing this Rician Channel -factor size for modulation、channel coding and MIMO structure to execute adaptive switch. We can accept error range to achieve maximum throughput by using we present method. However, user moment channel environment maybe already change result in adaptive switch become inaccurate when base station receiver user switch request and to proceed adaptive transmission in general time variant channel environment. Base Station receiver user switch request may forecast after channel variant proceed forecast adaptive switch and to increase adaptive switch accurate when we utilizing hidden Markov model(HMM) characteristic , according to high speed rail train measurement channel environment data match to similar channel environment.
By the above describe, the spectrum efficiency has 3 bps/Hz difference when use different MIMO structure to collocate orthogonal frequency division multiplexing (OFDM) system in different channel -factor. Maximum throughput may achieve 75 Mbps when utilizing channel -factor proceed adaptive switch. Using HMM proceed channel forecast adaptive transmission average more 5 Mbps than no forecast adaptive transmission when we simulate in high speed rail train channel environment.

並列關鍵字

MIMO ； Rician Channel K -factor ； CQI ； HMM ； OFDM

參考文獻

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