Noncoherent MIMO codes for low-medium SNRs, and layered MIMO space-time coding for coherent and noncoherent receivers

الموضوعات

علوم تطبيقية وتكنولوجية

الملخص

Wireless communication systems rely on training the receiver tolearn the channel state information (CSI) to communicate informationeffectively. In these coherent wireless communication systems,pilot signals known to the receiver are sent periodically to help thereceiver learn CSI which is needed for effective detection. However,mobile wireless standards are constantly aiming to increasesupported velocities and data rates. As the velocity of the receiver increase,the channel changes rapidly, and more frequent training is required,which compromise efficient communication of information.Moreover, multiple-antenna techniques are usually required nowadaysto increase supported data rates, which increases the numberof channel parameters that have to be estimated and thus requireslonger training periods. This lead to significant research activity inwireless communication systems that do not require channel knowledgeat the receiver for detection, and thus eliminate the need fortraining altogether. Those systems are called non-coherent.In the first part of thesis, we propose an new approach to constructspace-time codes for the multiple-input multiple-output (MIMO)noncoherent channel. Unlike designs which fixed the number oftransmit antennas active at any signaling interval, in our designs welet the number of the active transmit antennas vary over constellationpoints. We use numerical simulations to evaluate the performance ofour proposed designs. At low-to-moderate SNRs, simulations resultssuggest that our codes could provide significant performance gainsover codes designed using direct numerical optimization and exponentialmappings where the number of transmit antennas is fixed,especially at higher constellation cardinalities.In the second part, we consider layered space-time signaling overthe multiple input multiple output multicast channel. In our proposedscheme, information is encoded in two layers; a low-resolutionlayer and a high-resolution layer, and there are two classes of receivers;noncoherent receivers that do not have access to accurateCSI and are only able to decode the information in the low-resolutionlayer, and coherent receivers that have access to accurate CSI, andthus able to decode both the low-resolution and incremental highresolutioninformation. Low-resolution information is encoded usingGrassmannian MIMO codes, while high-resolution informationis encoded in the indices of the transmitter antennas active duringthe signaling interval using a scheme called generalized space shift keying(GSSK). The proposed HR layer is completely transparent to theLR layer. Moreover, we propose a computationally efficient two-stepdecoder. Simulation results suggest that the error performance of theproposed HR layer could be superior to existing schemes that usesconventional space-time codes synthesized from APM symbols andspace-time codes designed by direct numerical optimization on theunitary group.

روابط وملفات

التعريف والنوع

رقم الوثيقة

0725b4a1-2e21-4e5a-a5d0-b7280aff1d8d

رقم العقد

0

نوع الوسائط

Crawler

نوع المحتوى

الرسائل العلمية

صيغة المصدر

رسائل ماجيستير

نوع الملف

pdf image

أسماء الملفات

0725b4a1-2e21-4e5a-a5d0-b7280aff1d8d_1.pdf

بيانات النشر

ألقاب المؤلفين

[{"name_ar":"Karim Seddik","title_ar":"اشراف","title_en":"Supervision"},{"name_ar":"Mohamed Ali El Mossallamy","title_ar":"اعداد","title_en":"Preparation"}]

اللغة

English

المصدر والدورية

اسم المصدر

Noncoherent MIMO codes for low-medium SNRs, and layered MIMO space-time coding for coherent and noncoherent receivers

المحتوى والصفحات

عدد الصفحات

0

إشراف وإعداد

الإشراف

Karim Seddik

الإعداد

Mohamed Ali El Mossallamy

الاقتباسات الببليوغرافية