Diversity-multiplexing tradeoff in OFDMA systems: An H-matching approach

Bo Bai, Wei Chen, Khaled Letaief, Zhigang Cao

Research output: Contribution to journalArticle

21 Citations (Scopus)

Abstract

OFDMA is a promising technique because it is capable of improving the transmission reliability and efficiency of multi-user wireless communications. However, previous works on the performance of OFDMA did not properly consider the fundamental relationship between multiplexing and diversity in OFDMA systems. As a comprehensive performance metric, the diversity-multiplexing tradeoff will be applied in this paper to evaluate the subcarrier allocation scheme. The OFDMA system will be formulated into a correlated random bipartite graph model, in which, whether the edges occur or not depends on the distribution of the channel fading. The H-matching method, which is used to determine the maximum collection of vertex-disjoint copies of a fixed sub-graph H contained in a given graph, will then be developed to address the optimal subcarrier allocation problem. Theoretical analysis will show that the proposed H-matching method achieves the optimal outage performance at a given target multiplexing gain, which implies that the optimal diversity-multiplexing tradeoff can be achieved by only allocating subcarriers. Although the H-matching problem is NP-complete, the proposed Random Rotation and Expansion based Hopcroft-Karp (R 2EHK) algorithm can still achieve the asymptotically optimal outage performance (i.e., optimal diversity-multiplexing tradeoff) with a sub-linear complexity. Furthermore, the channel state information needed is only one bit per subcarrier. Simulation results will verify the theoretical analysis and will show that the performance loss of the R 2EHK algorithm is negligible compared to the exhaustive search method. In addition, it is also shown that the R 2EHK algorithm has at least a 2 dB SNR gain compared to the interleaved subcarrier allocation with water-filling power allocation in IEEE 802.16 standards.

Original languageEnglish
Article number6030125
Pages (from-to)3675-3687
Number of pages13
JournalIEEE Transactions on Wireless Communications
Volume10
Issue number11
DOIs
Publication statusPublished - Nov 2011
Externally publishedYes

Fingerprint

Diversity-multiplexing Tradeoff
Orthogonal Frequency Division multiple Access (OFDMA)
Subcarrier Allocation
Multiplexing
Theoretical Analysis
Outages
IEEE 802.16
Linear Complexity
Exhaustive Search
Power Allocation
Channel State Information
Optimal Allocation
Graph Model
Matching Problem
Performance Metrics
Asymptotically Optimal
Fading Channels
Search Methods
Random Graphs
Wireless Communication

Keywords

  • constraint H-matching
  • correlated random bipartite graph
  • diversity-multiplexing tradeoff
  • OFDMA
  • outage probability

ASJC Scopus subject areas

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

Cite this

Diversity-multiplexing tradeoff in OFDMA systems : An H-matching approach. / Bai, Bo; Chen, Wei; Letaief, Khaled; Cao, Zhigang.

In: IEEE Transactions on Wireless Communications, Vol. 10, No. 11, 6030125, 11.2011, p. 3675-3687.

Research output: Contribution to journalArticle

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