Impact of cooperative space–time/frequency diversity in OFDM‐based wireless sensor systems over mobile multipath channels.

Cooperative linear dispersion coding (LDC) can support arbitrary configurations of source nodes and destination nodes in virtual multi‐input–multi‐output systems. In this study, the authors investigate two spatial diversity applications of cooperative LDC for orthogonal frequency division multiplexing (OFDM)‐based wireless sensor systems in order to achieve space–time/frequency (ST/SF) diversity gains when transmitting over time‐/frequency‐selective fading channels. Cooperative LDC‐aided ST‐/SF‐OFDM is flexible in configuring various numbers of cooperative source nodes and time‐slots or frequency‐tones. Their results show that the ST‐OFDM scheme is sensitive to exploiting diversity gains, subject to the impact of varying channel Doppler spreads; while the performance of SF‐OFDM is mainly subject to delay spread. Specifically, when the system involves more than two cooperative nodes, the cooperative LDC‐aided ST‐/SF‐OFDM outperforms the cooperative orthogonal block codes (e.g. Tarokh's codes) aided ST‐/SF‐OFDM, when communicating over a higher Doppler/delay spread. [ABSTRACT FROM AUTHOR]