Achieving delay diversity in asynchronous underwater acoustic (UWA) cooperative communication systems

Mojtaba Rahmati, Tolga M. Duman

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

In cooperative UWA systems, due to the low speed of sound, a node can experience significant time delays among the signals received from geographically separated nodes. One way to combat the asynchronism issues is to employ orthogonal frequency division multiplexing (OFDM)-based transmissions at the source node by preceding every OFDM block with an extremely long cyclic prefix (CP) which reduces the transmission rates dramatically. One may increase the OFDM block length accordingly to compensate for the rate loss which also degrades the performance due to the significantly time-varying nature of UWA channels. In this paper, we develop a new OFDM-based scheme to combat the asynchronism problem in cooperative UWA systems without adding a long CP (in the order of the long relative delays) at the transmitter. By adding a much more manageable (short) CP at the source, we obtain a delay diversity structure at the destination for effective processing and exploitation of spatial diversity by utilizing a low complexity Viterbi decoder at the destination, e.g., for a binary phase shift keying (BPSK) modulated system, we need a two-state Viterbi decoder. We provide pairwise error probability (PEP) analysis of the system for both time-invariant and block fading channels showing that the system achieves full spatial diversity. We find through extensive simulations that the proposed scheme offers a significantly improved error rate performance for time-varying channels (typical in UWA communications) compared to the existing approaches.

Original languageEnglish (US)
Article number6733257
Pages (from-to)1367-1379
Number of pages13
JournalIEEE Transactions on Wireless Communications
Volume13
Issue number3
DOIs
StatePublished - 2014

Fingerprint

Underwater Acoustic Communication
Cooperative communication
Cooperative Communication
Underwater acoustics
Cooperative Systems
Orthogonal frequency division multiplexing
Communication Systems
Cyclic Prefix
Communication systems
Orthogonal Frequency Division multiplexing (OFDM)
Underwater Acoustics
Spatial Diversity
Binary phase shift keying
Vertex of a graph
Acoustic wave velocity
Time-varying Channels
Fading channels
Transmitters
Error Probability
Time delay

Keywords

  • Asynchronous communication
  • cooperative systems
  • OFDM
  • underwater acoustics

ASJC Scopus subject areas

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

Cite this

Achieving delay diversity in asynchronous underwater acoustic (UWA) cooperative communication systems. / Rahmati, Mojtaba; Duman, Tolga M.

In: IEEE Transactions on Wireless Communications, Vol. 13, No. 3, 6733257, 2014, p. 1367-1379.

Research output: Contribution to journalArticle

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