  This paper focuses on analog network coding (ANC) and time division
broadcasting (TDBC) which are two major protocols used in bidirectional
cooperative networks. Lower bounds of the outage probabilities of those two
protocols are derived first. Those lower bounds are extremely tight in the
whole signal-to-noise ratio (SNR) range irrespective of the values of channel
variances. Based on those lower bounds, finite-SNR diversity-multiplexing
tradeoffs of the ANC and TDBC protocols are obtained. Secondly, we investigate
how to efficiently use channel state information (CSI) in those two protocols.
Specifically, an optimum power allocation scheme is proposed for the ANC
protocol. It simultaneously minimizes the outage probability and maximizes the
total mutual information of this protocol. For the TDBC protocol, an optimum
method to combine the received signals at the relay terminal is developed under
an equal power allocation assumption. This method minimizes the outage
probability and maximizes the total mutual information of the TDBC protocol at
the same time.
