Bound of capacity in distributed MIMO repeater system with AF method

Multiple-input multiple-output (MIMO) repeater systems have been discussed in several published papers. When a repeater has only one antenna element, the propagation environment is called keyhole. In this kind of scenario the achievable channel capacity and link quality are decreased. Another limit is when the number of the antenna elements of a repeater is larger than that of a MIMO transceiver, the channel capacity cannot be increased. In this paper, in order to obtain high channel capacity, the repeaters are distributed in series. We optimize the position of each repeater for upper bound of channel capacity with each number of repeaters, and the upper bound of channel capacity when the number of repeater is assumed to be infinite.