تخمین کانال MIMO با استفاده از QRD و الگوریتم وفقی LMS

نویسندگان

تهران - دانشگاه امام حسین (علیه‌السلام) - دانشکده فناوری اطلاعات و ارتباطات

چکیده

تخمین کانال یکی از مهم‌ترین عواملی است که در سیستم‌های MIMO  نقش تعیین‌کننده‌ای در ارزیابی عملکرد دارد، روش‌های متفاوتی برای تخمین سیستم‌های MIMO وجود دارد که روش‌های وفقی، ازجمله این روش‌ها می‌باشد. در میان روش‌های وفقی نیز الگوریتم LMS دارای محبوبیت بیش‌تری است و بیش‌تر شرایط یک فیلتر مناسب، ازجمله پیاده‌سازی ساده و پیچیدگی کم‌تر را دارد. از سویی دیگر، برخی از آشکارسازهای مهم در سیستم‌های MIMO از تجزیه QR برای استخراج سیگنال ارسالی استفاده می‌کنند که دارای پیچیدگی در محاسبات می‌باشد. در این مقاله روش جدیدی برای تخمین QR کانال مخابراتیMIMO ارائه شده است و به جای اینکه مشخصه کانال H تخمین زده شود و بعد در آشکارسازی تجزیه QR صورت گیرد، از همان ابتدا و مستقیماً ماتریس‌های Q و R با الگوریتم LMS تخمین زده می‌شود. درواقع ماتریس کانال با تخمین Q و R نیز به دست می‌آید. نتایج شبیه‌سازی در مطلب نشان می‌دهد استفاده از الگوریتم LMS و تجزیه QR در تخمین کانال، با تعداد تکرارهای بالا و یا افزایش SNR، کاهش خطا را در پی خواهد داشت.

کلیدواژه‌ها


عنوان مقاله [English]

MIMO Channel Estimation by QR Decomposition and LMS Adaptive Filter

نویسندگان [English]

  • E. Dashtian
  • M. Okhovat
  • H. Arezomand
Faculty of Technology of Information & Communication, University of Imam Hossein, Tehran, Iran
چکیده [English]

Channel estimation is one of the most decisive factors in evaluating performance of the MIMO systems. There are different methods for estimation of MIMO systems, that, adaptive algorithm is which. Among adaptive algorithms, Least Mean Square (LMS) algorithm is the most popular because it has the features of a proper filter including simplicity in applying and no complexity in using. In the other hand, some of important detectors in MIMO systems use QR decomposition for signal extraction, which is of a higher level of complexity. In this paper, a new method for MIMO channel QR estimation is proposed and instead of estimating the channel matrix H and them decomposing QR in detector, from the beginning, Q and R estimated directly actually, channel matrix is detained through the estimation of Q and R. according to MATLAB simulation applying LMS algorithm and QR decomposition in channel estimation with iteratively and/or SNR increment will result in the error reduction.

کلیدواژه‌ها [English]

  • MIMO
  • channel estimation
  • adaptive filter
  • LMS
  • QR decomposition
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