Telefonaktiebolaget Lm Ericsson (publ)

Darlan Cavalcante Moreira

Ari Kangas

Markus Ringström

Yuri C B Silva

Walter Cruz Freitas, Jr

Paulo G Normando

Carlos I R Bandeira

Yuri CB Silva

Walter C Freitas Junior

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.

Method and apparatus for adaptive cancellation of external interference

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.

Reduced complexity frequency band and virtual antenna combination (VAC) selection

Growing community of inventors

Fortaleza-CE, Brazil

Darlan Cavalcante Moreira