Spectral efficiency enhancement in multi-channel systems using redundant transmission and diversity reception

Haewoon Nam*, Young Chai Ko, Mohamed Slim Alouini

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Scopus citations


We first consider conventional multi-channel systems with fixed-power variable-rate transmission of independent data streams as a function of channel variations. In these conventional systems, no data is transmitted through the sub-channels whose received signal strength is below a certain cutoff threshold. We then propose new hybrid adaptive modulation and diversity schemes for multi-channel transmission systems. The proposed hybrid schemes attempt to increase the overall spectral efficiency by (i) transmitting redundant information symbols through the deeply faded sub-channels that are not to be used in conventional multi-channel systems and then (ii) diversity combining these replicas at the receiver end. We evaluate the performance of the newly proposed hybrid schemes and compare their spectral efficiency with that of (i) the conventional scheme and (ii) a benchmark scheme which maximizes the overall spectral efficiency but is too complex for practical implementation. We show using some selected numerical examples that the proposed hybrid schemes offer spectral efficiency very close to that of the optimal scheme with much reduced complexity.

Original languageEnglish (US)
Article number4543066
Pages (from-to)2143-2153
Number of pages11
JournalIEEE Transactions on Wireless Communications
Issue number6
StatePublished - Jun 2008
Externally publishedYes


  • Adaptive modulation
  • Diversity combining
  • Multi-channel wireless systems

ASJC Scopus subject areas

  • Applied Mathematics
  • Electrical and Electronic Engineering
  • Computer Science Applications


Dive into the research topics of 'Spectral efficiency enhancement in multi-channel systems using redundant transmission and diversity reception'. Together they form a unique fingerprint.

Cite this