کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
449130 1443186 2012 9 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Performance of variable-power adaptive MQAM with transmit antenna selection and delayed feedback in Nakagami Fading channel
موضوعات مرتبط
مهندسی و علوم پایه مهندسی کامپیوتر شبکه های کامپیوتری و ارتباطات
پیش نمایش صفحه اول مقاله
Performance of variable-power adaptive MQAM with transmit antenna selection and delayed feedback in Nakagami Fading channel
چکیده انگلیسی

In this paper, the performance of MIMO systems with variable-power (VP) adaptive MQAM and transmit antenna selection (TAS) over Nakagami-m fading channel is presented. The optimum switching thresholds for attaining maximum spectrum efficiency (SE) subject to a target bit error rate (BER) and an average power constraint are derived. It is shown that the Lagrange multiplier in the constrained SE optimization will be unique if the existence condition for MIMO system with TAS is satisfied. A practical iterative algorithm based on Newton's method for finding the Lagrange multiplier is proposed. By using the switching thresholds, closed-form expressions of the SE and average BER are obtained. Besides, BER expressions with delayed feedback are derived for VP and constant-power (CP) systems, respectively. With these expressions, the impact of feedback delay on the BER performance is effectively assessed. Computer simulation for SE and BER shows that the theoretical analysis and simulation are in good agreement. The results show that the VP adaptive modulation (AM) system with TAS provides better SE than the CP counterpart and VP AM system with space-time coding, and has slight BER performance degradation for the normalized time delay less than 0.01.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: AEU - International Journal of Electronics and Communications - Volume 66, Issue 4, April 2012, Pages 340–348
نویسندگان
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