Capacity of MIMO systems with asynchronous PAM
IEEE Transactions on Communications
Channel Access Scheme for MIMO-Enabled Ad Hoc Networks with Adaptive Diversity/Multiplexing Gains
Mobile Networks and Applications
DMT analysis of asynchronous OFDM decode-and-forward cooperative networks
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
Performance of asynchronous amplify-and-forward cooperative relay networks
GLOBECOM'09 Proceedings of the 28th IEEE conference on Global telecommunications
DAC: distributed asynchronous cooperation for wireless relay networks
INFOCOM'10 Proceedings of the 29th conference on Information communications
IEEE Transactions on Wireless Communications
Performance of asynchronous two-relay two-hop wireless cooperative networks
IEEE Transactions on Wireless Communications
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Synchronization of relay nodes is an important and critical issue in exploiting cooperative diversity in wireless networks. In this paper, two asynchronous cooperative diversity schemes are proposed, namely, distributed delay diversity and asynchronous space-time coded cooperative diversity schemes. In terms of the overall diversity-multiplexing (DM) tradeoff function, we show that the proposed independent coding based distributed delay diversity and asynchronous space-time coded cooperative diversity schemes achieve the same performance as the synchronous space-time coded approach which requires an accurate symbol-level timing synchronization to ensure signals arriving at the destination from different relay nodes are perfectly synchronized. This demonstrates diversity order is maintained even at the presence of asynchronism between relay node. Moreover, when all relay nodes succeed in decoding the source information, the asynchronous space-time coded approach is capable of achieving better DM tradeoff than synchronous schemes and performs equivalently to transmitting information through a parallel fading channel as far as the DM tradeoff is concerned. Our results suggest the benefits of fully exploiting the space-time degrees of freedom in multiple antenna systems by employing asynchronous space-time codes even in a frequency-flat-fading channel. In addition, it is shown asynchronous space-time coded systems are able to achieve higher mutual information than synchronous space-time coded systems for any finite signal-to-noise ratio (SNR) when properly selected baseband waveforms are employed.