  In this paper, a symbol-level selective transmission for virtual full-duplex
(FD) relaying networks is proposed, which aims to mitigate error propagation
effects and improve system spectral efficiency. The idea is to allow two
half-duplex relays, mimicked as FD relaying, to alternatively serve as
transmitter and receiver to forward the source's messages. In this case, each
relay predicts the correctly decoded symbols of its received frame, based on
the generalized square deviation method, and discard the erroneously decoded
symbols, resulting in fewer errors being forwarded to the destination. Then, a
modified maximum \textit{a posteriori} receiver at the destination is provided
to eliminate the inter-frame interference and identify the positions of
discarded symbols from the relays. In addition, the diversity-multiplexing
trade-off (DMT) for our proposed scheme is also analysed. It is found that our
proposed scheme outperforms the conventional selective decode-and-forward
(S-DF) relaying schemes, such as cyclic redundancy check based S-DF and
threshold based S-DF, in terms of DMT. Moreover, the bit-error-rate performance
are also simulated to confirm the DMT results.
