Optimal multiband joint detection for spectrum sensing in cognitive radio networks

Zhi Quan, Shuguang Cui, Ali H. Sayed, H. Vincent Poor

Research output: Contribution to journalArticlepeer-review

601 Scopus citations

Abstract

Spectrum sensing is an essential functionality that enables cognitive radios to detect spectral holes and to opportunistically use under-utilized frequency bands without causing harmful interference to legacy (primary) networks. In this paper, a novel wideband spectrum sensing technique referred to as multiband joint detection is introduced, which jointly detects the primary signals over multiple frequency bands rather than over one band at a time. Specifically, the spectrum sensing problem is formulated as a class of optimization problems, which maximize the aggregated opportunistic throughput of a cognitive radio system under some constraints on the interference to the primary users. By exploiting the hidden convexity in the seemingly nonconvex problems, optimal solutions can be obtained for multiband joint detection under practical conditions. The situation in which individual cognitive radios might not be able to reliably detect weak primary signals due to channel fading/shadowing is also considered. To address this issue by exploiting the spatial diversity, a cooperative wideband spectrum sensing scheme refereed to as spatial-spectral joint detection is proposed, which is based on a linear combination of the local statistics from multiple spatially distributed cognitive radios. The cooperative sensing problem is also mapped into an optimization problem, for which suboptimal solutions can be obtained through mathematical transformation under conditions of practical interest. Simulation results show that the proposed spectrum sensing schemes can considerably improve system performance. This paper establishes useful principles for the design of distributed wideband spectrum sensing algorithms in cognitive radio networks.

Original languageEnglish (US)
Pages (from-to)1128-1140
Number of pages13
JournalIEEE Transactions on Signal Processing
Volume57
Issue number3
DOIs
StatePublished - Mar 10 2009

All Science Journal Classification (ASJC) codes

  • Signal Processing
  • Electrical and Electronic Engineering

Keywords

  • Cognitive radio
  • Cooperative sensing
  • Hypothesis testing
  • Multiband joint detection
  • Nonlinear optimization
  • Spectrum sensing

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