The next proposition informs us of relay precoders for SMSE minimization under RSPC in MRMU network.
Proposition 1: In the downlink MRMU network under RSPC, the rth relay precoder for SMSE minimization is given by
As the first step for investigation on the SMSE achievability in MRMU MIMO network, we assumed RSPC.
Proposition 2: In the downlink MRMU system under PRPC, BS transmitter and the rth relay's precoder for SMSE minimization are given respectively by
Since our research lays emphasis on observing the ultimate achievability in MRMU MIMO network, we will compare JBMR-RSPC and JBMR-PRPC with the single giant relay of the SMSE minimization scheme , which we think will give some insight into the effectiveness of our proposed algorithm.
Thus our MRMU MIMO network is not special case of multipoint-to-multipoint network since one BS serves multiple users.
However, it is expected that this work gives a foundation to examine practical design in the MRMU MIMO network by introducing useful tools such as BD precoder and SMSE duality and showing how to approach the transceiver design problem.
We proposed an iterative transceiver design called JBDMR using local CSI at relays in an MRMU MIMO network.