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 language | English (US) |
|---|---|
| Article number | 6733257 |
| Pages (from-to) | 1367-1379 |
| Number of pages | 13 |
| Journal | IEEE Transactions on Wireless Communications |
| Volume | 13 |
| Issue number | 3 |
| DOIs | |
| State | Published - 2014 |
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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 journal › Article
}
TY - JOUR
T1 - Achieving delay diversity in asynchronous underwater acoustic (UWA) cooperative communication systems
AU - Rahmati, Mojtaba
AU - Duman, Tolga M.
PY - 2014
Y1 - 2014
N2 - 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.
AB - 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.
KW - Asynchronous communication
KW - cooperative systems
KW - OFDM
KW - underwater acoustics
UR - http://www.scopus.com/inward/record.url?scp=84897915194&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84897915194&partnerID=8YFLogxK
U2 - 10.1109/TWC.2014.020414.130538
DO - 10.1109/TWC.2014.020414.130538
M3 - Article
VL - 13
SP - 1367
EP - 1379
JO - IEEE Transactions on Wireless Communications
JF - IEEE Transactions on Wireless Communications
SN - 1536-1276
IS - 3
M1 - 6733257
ER -