Optimal Adaptive Transmission for a Cognitive Radio With Sensing

Abstract

We propose a randomized transmission scheme for minimizing a time-averaged cost metric in a cognitive radio. We assume that a single cognitive radio (i.e., a transmitter and receiver) hops over N orthogonal channels, each occupied by a primary user whose ON-OFF activity is modeled by a two-state Markov chain. We assume that the cognitive radio senses the activity in each channel at the beginning of every symbol period, and that a usage cost is assigned to each channel that depends on the channel's physical-layer characteristics and the sensing outcome. We fully characterize the transmission scheme that minimizes the time-averaged cost, subject to interference constraints imposed by the primaries. Finally, we evaluate the performance for two special cases of the cost: the bit error rate and (lower and upper bounds on) the channel capacity.

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Document Details

Document Type
Technical Report
Publication Date
Apr 01, 2008
Accession Number
ADA506485

Entities

People

  • Lang Tong
  • Saswat Misra
  • Stefan Geirhofer

Organizations

  • United States Army Research Laboratory

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Abstracts
  • Channel Capacity
  • Cognitive Radio
  • Collisions
  • Detectors
  • Frequency
  • Frequency Shift
  • Game Theory
  • Information Theory
  • Intervals
  • Markov Chains
  • Probability
  • Random Variables
  • Signal Processing
  • Stochastic Processes
  • Time Intervals
  • Transmitters

Readers

  • Radio communications and signal processing.