Resource Allocation in Downlink Multiuser Multicarrier Wireless Systems

Prof. Brian L. Evans

Wireless Networking and Communications Group
The University of Texas at Austin


OFDM System Design Research


Broadband wireless standards, such as IEEE 802.16e-2005 and those emerging from the Third-Generation Partnership Project Long Term Evolution, use Orthogonal Frequency Division Multiple Access (OFDMA) as the preferred physical layer multiple access scheme, esp. for the downlink. In the downlink direction, an OFDMA base station would simultaneously transmit data to different users using different subchannels.

This talk examines the allocation of subcarriers, rates, and power to the different users in a downlink OFDMA system. To take advantage of the time-varying nature of the wireless channel, we propose to maximize time-averaged (ergodic) rates. This approach allows us to exploit the temporal dimension to improve communication performance.

Based on unified algorithmic framework that uses dual optimization techniques, we present optimal downlink resource allocation algorithms that

  1. have linear complexity in numbers of subcarriers and users
  2. are available for allocating continuous or discrete rates to users
  3. apply to perfect and partial knowledge of the channel
  4. are amenable to implementation in fixed-point arithmetic and data types
Collaboration with Dr. Ian Wong when he was at UT Austin.


Dr. Brian L. Evans joined the electrical and computer engineering faculty at UT Austin in fall 1996. My research interests are in embedded real-time digital signal processing systems, esp. in the context of communication systems and image processing systems. That is, my research group develops signal processing theory and algorithms, and also translates the theory and algorithms into design methods and prototype implementations. My research group is the Embedded Signal Processing Laboratory, which is part of both the Wireless Networking and Communications Group and Center for Perceptual Systems