Abstract: In MU-MIMO scenarios, uncoordinated or external interference may be very significant. Such external interference can degrade the system performance as much as the internal interference. To address these problems, a desired signal subspace can be changed to avoid the external interference as much as possible. This technique can be applied in conjunction with systems that already cancel internal interference, such as Interference Alignment and Joint Processing. An original signal space may be broken down to desired and interference subspaces that are orthogonal to each other. The receiver can notify the transmitter of the boundary, and transmitter in turn can project the transmitted signal to fall into the desired subspace. The receiver can project the received signal into the desired subspace, which cancels everything not contained in the desired subspace.

Abstract: In MU-MIMO scenarios, uncoordinated or external interference may be very significant. Such external interference can degrade the system performance as much as the internal interference. To address these problems, a desired signal subspace can be changed to avoid the external interference as much as possible. This technique can be applied in conjunction with systems that already cancel internal interference, such as Interference Alignment and Joint Processing. An original signal space may be broken down to desired and interference subspaces that are orthogonal to each other. The receiver can notify the transmitter of the boundary, and transmitter in turn can project the transmitted signal to fall into the desired subspace. The receiver can project the received signal into the desired subspace, which cancels everything not contained in the desired subspace.

Abstract: A downlink Channel Quality Indicator (CQI) is estimated in two steps. Initially, one or more subsets of received reference symbols are selected. If the transmitter may transmit signals in one or more of two or more frequency bands, optimal frequency bands are selected based on a first subset of reference symbols. If the transmitter may transmit using one of two or more VACs, an optimal VAC is selected based on the first or a second subset of reference symbols. An SINR is subsequently calculated for the selected frequency band and VAC combination, based on more than the subset(s) of reference symbols.

Abstract: According to the teachings presented herein, each base station in a group of base stations is linked to an associated terminal as a receiver-transmitter pair. These receiver-transmitter pairs reuse channelization resources, such that each terminal represents a source of other-cell interference (also referred to as multi-user interference or MUI) for other terminals in neighboring cells that are reusing all or some of the same channelization resources. Accordingly, the base stations implement a gaming-based algorithm to mitigate MUI for the multiple-input-multiple-output (MIMO) uplink signals received from their associated terminals. More particularly, each base station functions as a player in a game, in which the allowed gaming action is the selection of the precoding matrix to be used for MIMO uplink transmissions to the base station from an associated terminal.

Abstract: A downlink Channel Quality Indicator (CQI) is estimated in two steps. Initially, one or more subsets of received reference symbols are selected. If the transmitter may transmit signals in one or more of two or more frequency bands, optimal frequency bands are selected based on a first subset of reference symbols. If the transmitter may transmit using one of two or more VACs, an optimal VAC is selected based on the first or a second subset of reference symbols. An SINR is subsequently calculated for the selected frequency band and VAC combination, based on more than the subset(s) of reference symbols.