Achievable Rates of MIMO Bidirectional Broadcast Channels With Self-Interference Aided Channel Estimation

In this paper, we consider the broadcast (BRC) phase of two-way decode-and-forward (DF) relaying systems. The channel in that phase is called the bidirectional broadcast channel. Its achievable rates are calculated when the self-interference aided channel estimation scheme is applied. We consider a block- fading channel model in the BRC phase and exploit the self- interference that is inherent in two-way relaying techniques to get an initial estimate of the channel at the receiving terminals. This initial channel estimate is utilized to decode the data in the first several time slots of each coherence interval. Data- aided approaches are then employed to improve the channel estimates in the following time slots of each coherence interval. The spectral efficiency improvement for systems employing this self-interference aided channel estimation scheme is quantified by comparing its achievable rates to that of the traditional pilot- aided channel estimation scheme.