Now showing items 1-12 of 12

  • Cooperative Communications in the Fading Channel 

    Ahmed, Nasir; Aazhang, Behnaam (2005-03-01)
    Cooperative coding is a communication paradigm that pools distributed resources of different nodes in a network, such that the nodes act like a collaborative system instead of greedy adversarial participants. Cooperation ...
  • Exploiting Feedback in Cooperative Relay Networks 

    Ahmed, Nasir (2005-08-01)
    Recent results on multiple antenna transmission techniques have shown great po- tential in their ability to improve the overall performance in fading channels. Despite the promise shown by employing multiple antenna's, ...
  • Finite Backlog Effects on Downlink Scheduling 

    Ahmed, Nasir; Khojastepour, Mohammad; Sabharwal, Ashutosh; Aazhang, Behnaam (2003-11-20)
    In a multi-user downlink system, the use of channel estimates in the scheduling process can significantly improve the spectral efficiency. Recent work has shown that from a sum rate capacity standpoint, and assuming infinite ...
  • Multilevel coding of broadcast video over wirless channels 

    Cakareski, Zeljko; Ahmed, Nasir; Dhar, Aditya; Aazhang, Behnaam (2002-05-20)
    This paper addresses the problem of broadcasting video over wireless channels. In such a scenario, different end users perceive the video signal through channels with different quality. We propose a source-channel coding ...
  • On Power Control with Finite Rate Feedback for Cooperative Relay Networks 

    Ahmed, Nasir; Khojastepour, Mohammad; Sabharwal, Ashutosh; Aazhang, Behnaam (2004-03-01)
    Power control strategies with finite rate feedback are studied for the cooperative channel. The main contribution of this paper is to show that quantized feedback information can lead to significant reduction in outage ...
  • Outage Minimization and Optimal Power Control for the Fading Relay Channel 

    Ahmed, Nasir; Khojastepour, Mohammad; Aazhang, Behnaam (2004-05-01)
    In this work, we show that in the wireless relay network, a tremendous savings in energy can be achieved by having side information at the transmitters and by employing power control. We present efficient protocols and the ...
  • Outage Minimization with Limited Feedback for the Fading Relay Channel 

    Ahmed, Nasir; Khojastepour, Mohammad; Sabharwal, Ashutosh; Aazhang, Behnaam (2004-12-01)
    In this work, we consider practical methods to approach the theoretical performance limits in the fading relay channel under different assumptions of transmitter channel knowledge. Specifically, we consider two degrees of ...
  • Performance improvements with feedback in cooperative relay networks 

    Ahmed, Nasir (2006)
    Recent results on multiple antenna transmission techniques have shown great potential in their ability to improve the overall performance in fading channels. Despite the promise shown by employing multiple antenna's, ...
  • Power issues in communication systems 

    Ahmed, Nasir (2002)
    In this work, we are concerned with power efficient communication techniques for wireless mobile devices. In this direction the effects of nonlinear amplifiers in communications systems are first studied, as they tend to ...
  • Power Issues in Communication Systems 

    Ahmed, Nasir (2002-04-20)
    In this work, we are concerned with power efficient communication techniques for wireless mobile devices. In this direction the effects of nonlinear amplifiers in communications systems are first studied, as they tend to ...
  • Throughput Gains with Limited Feedback in Cooperative Relay Networks 

    Ahmed, Nasir; Aazhang, Behnaam (2005-06-01)
    In this work, we consider delay-constrained systems in cooperative relay networks, and derive methods to maximize the throughput when a limited feedback link to the transmitter nodes exist. We derive the optimal rate control ...