Channel state information (CSI) feedback is a challenging issue in frequency division multiplexing (FDD) massive MIMO systems. This paper studies a cooperative feedback scheme, where the users first exchange their CSI with each other by exploiting device-to-device (D2D) communications, then compute the precoder by themselves, and feed back the precoder to the base station (BS). Analytical resul...

Pilot-assisted channel estimation has been studied only in common cooperative AF (Amplify-and-Forward) OFDM which has no feedback mechanism. In this paper, for cooperative AF-OFDM system, we propose a feedback technique in which the pilot allocation mechanism is adapted to the cooperative mobile channel. Then we show how uniform pilots may no longer be optimal compared with our pilots. After de...

introduction: acquisition of intelligible english pronunciation and comprehension of medical texts has been considered as an important need for medical students.  this can be improved by employing different methods and taking into consideration various learning styles of students. this study is an attempt to reveal the effect of cooperative learning on enhancing pronunciation and reading compre...

This paper presents a consensus-based robust cooperative control framework for a wide class of linear time-invariant (LTI) systems, namely Negative-Imaginary (NI) systems. Output feedback, dynamic, Strictly Negative-Imaginary (SNI) controllers are applied in positive feedback to heterogeneous multi-input-multi-output (MIMO) plants through the network topology to achieve robust output feedback c...

In accordance with the approach of open distributed learning environments (ODLEs), we have developed a framework system for computer-supported cooperative learning and working. This distributed shared workspace system is well suited for monitoring and assessing group interaction in co-located and distant scenarios. It provides adaptable mechanisms for the automated micro-analysis of processes o...