Method in a wireless communication system

Abstract

The present invention relates to a method in a multiple antenna wireless communication system, said wireless communication system comprising at least one transmit node and at least one receive node, said method comprising the steps of signalling by said receive node at least one first transmission rank r to said transmit node, where1<=r<=R, wherein R is a maximum available rank for a transmission between said transmit node and said receive node, and wherein at least one predefined precoding matrix corresponds to said first transmission rank r; determining by said transmit node a second transmission rank r' for transmitting data from said transmit node to said receive node, where 1<=r'<=R, and comprising the further steps of: defining at least two subsets of precoding matrices for at least one of said at least one first transmission rank r; selecting one of said at least two subsets of precoding matrices based on a channel quality estimate for a radio channel between said transmit node and said receive node; and signalling said selected one subset of precoding matrices, wherein said selected one subset of precoding matrices is associated with said at least one predefined precoding matrix corresponding to said at least one first transmission rank r. Furthermore, the invention also relates to a method in a receive node, a receive node device, a method in a transmit node, a transmit node device, a computer program and a computer program product.

Description

technical field [0001] The invention relates to a method in a wireless communication system, more particularly to a method according to the preamble of claim 1 . Furthermore, the invention relates to a method in a receiving node, a receiving node device, a method in a transmitting node, a transmitting node device, a computer program and a computer program product. Background technique [0002] It is well known that utilizing linear precoding at the transmitter side can significantly improve performance in wireless communication systems when multiple antennas are used. Such linear precoding has been implemented in accordance with the IEEE802.16-2005 standard and the 3GPP Rel.8 / 9 / 10 Long Term Evolution (LTE) standard. [0003] To support precoding at the transmitter side in the downlink (DL), the receiver (also called user equipment (UE)) feeds back channel state information about the wireless channel passed between the transmitter antenna and the receiver antenna ( CSI). T...

AI Technical Summary

Problems solved by technology

For normal transmission without CoMP, there is only one site, and the path loss is almost the same for the antennas deployed in the site, so it is useless to define multiple subsets of precoding matrices corresponding to different path losses and different numbers of antennas

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