Multi-antenna device

摘要

The invention provides a method for self-interference suppression in a multi-antenna device that is part of a communication channel between a transmitter and a receiver of a wireless communication system. The communication system uses the multi-antenna device, the multi-antenna device is located between the transmitter and the receiver and uses antennas and a relay unit forwarding signals from the transmitter to the receiver. The communication channel has a transmit channel, defined by a transmit channel matrix between the transmitter and the multi-antenna device, a receive channel defined by a receive channel matrix, between the multi-antenna device and the receiver and a self-interference channel between an output and an input side of the multi-antenna device. The self-interference channel is defined by a self-interference channel matrix wherein the method comprises the steps of: • quipping the multi-antenna device with at least three antennas and; • suppressing the self-interference channel by using at least one filtering matrix arrangement being inserted between the antennas and the relay unit. The invention also provides a node in a wireless communication system comprising the multi-antenna device for self-interference suppression in the multi-antenna device module that is part of a communication channel.

主权项

1. A method for self-interference suppression in a multi-antenna device that is part of a communication channel between a transmitter and a receiver of a wireless communication system the multi-antenna device being located between the transmitter and the receiver and using antennas and a relay unit for forwarding signals from the transmitter to the receiver, the communication channel having a transmit channel, defined by a transmit channel matrix between the transmitter and the multi-antenna device, a receive channel defined by a receive channel matrix, between the multi-antenna device and the receiver, and a self-interference channel between an output and an input side of the multi-antenna device, the self-interference channel being defined by a self-interference channel matrix, the method comprising:
equipping the multi-antenna device with at least four antennas of which at least two antennas are input antennas (310) located at the input side facing the transmit channel and at least two antennas are output antennas located at the output side facing the receive channel; and suppressing the self-interference channel by using two filtering matrix arrangements, (i) a receive filtering matrix arrangement being inserted between the input antennas and the relay unit and (ii) a transmit filtering matrix arrangement being inserted between the output antennas and the relay unit, wherein the receive filtering matrix arrangement is defined by a receive filtering matrix Wr, the transmit filtering matrix arrangement is defined by a transmit filtering matrix Wt, and said transmit and said receive filtering arrangements cancel at least one eigenmode of the self-interference channel, by choosing columns of the transmit and the receive filtering matrices to be orthogonal to said at least one eigenmode of the self-interference channel that is to be cancelled, the self-interference suppression by cancelling said at least one eigenmode is made with the transmit and the receive filtering matrix arrangements meeting a selection criterion for minimizing risk of loss of one or several dominating eigenmodes of one or both of the transmit channel and the receive channel.