Now showing items 1-8 of 8

  • On the Asymptotic Performance of Multiple Antenna Channels with Fast Channel Feedback 

    Khoshnevis, Ahmad; Sabharwal, Ashutosh (2005-10-01)
    In this paper, we analyze the asymptotic performance of multiple antenna channels where the transmitter has either perfect or finite bit channel state information. Using the diversitymultiplexing tradeoff to characterize ...
  • On the Overhead-Delay Tradeoff in Carrier Sense Collision Channel 

    Khoshnevis, Ahmad; Sabharwal, Ashutosh (2005-09-01)
    In this paper, we study the impact of delay constraints on the throughput of a queued multiple-access system. We model the channel as a collision channel with \emph{carrier sense} to capture the inherent information sharing ...
  • Achievable Diversity and Multiplexing in Multiple Antenna Systems with Quantized Power Control 

    Khoshnevis, Ahmad; Sabharwal, Ashutosh (2005-05-01)
    We consider a multiple antenna system with finite rate feedback, in which the quantized channel state information at the transmitter is used solely for temporal power control. We show that similar to systems without feedback, ...
  • On Diversity and Multiplexing Gain of Multiple Antenna Systems with Transmitter Channel Information 

    Khoshnevis, Ahmad; Sabharwal, Ashutosh (2004-10-01)
    We quantify the multiplexing-diversity tradeoff of a multiple-input multiple-output (MIMO) system, when the channel state information (CSI) is known perfectly at the receiver and partially at the transmitter. The partial ...
  • Performance of Quantized Power-Control in Multiple Antenna Systems 

    Khoshnevis, Ahmad; Sabharwal, Ashutosh (2004-06-01)
    In this paper, we analyze the outage probability of a single user system with multiple antennas at the transmitter, single antenna at the receiver, and finite rate feedback power control. The optimum power control is complex ...
  • Network Channel Estimation in Cooperative Wireless Networks 

    Khoshnevis, Ahmad; Sabharwal, Ashutosh (2003-05-20)
    In distributed wireless networks, where nodes actively participate in helping communication for other nodes, they are typically unaware of their neighourhood and hence have to "estimate" it before sending any useful data. ...
  • Coding-Spreading Tradeoff for Lattice Codes 

    Khoshnevis, Ahmad (2001-04-20)
    A fixed bandwidth expansion can be achieved either by coding or spreading, while each have different effect on the resultant signal space. Coding increases both Shannon and Fourier bandwidth whereas spreading only increases ...
  • An Introduction to Wideband CDMA 

    Khoshnevis, Ahmad (2000-05-20)
    The main goal of this project is to design a space-time code system for wideband code division multiple access (Wideband CDMA). In this work we tried to make the essential foundations for this goal. There are two key ...