Telefonaktiebolaget Lm Ericsson (publ)

Walter Cruz Freitas, Jr

Yuri C B Silva

Gabor Fodor

Francisco Rafael Marques Lima

Paulo G Normando

Darlan Cavalcante Moreira

Khaled Ardah

Ricardo Brauner Dos Santos

Francisco Porto Cavalcanti

Carlos I R Bandeira

A method of updating spatial filters in a radio network comprising at least two transmit nodes each in radio communication with at least one receive node on a Multiple-Input Multiple-Output (MIMO) radio channel, comprises transmitting, from the respective transmit node, first reference signals precoded by a first spatial filter of the respective transmit node; and receiving, from the receive nodes, second reference signals that are precoded using a second spatial filter of the respective receive node and an error matrix of the respective receive node. The second spatial filter depends on a channel estimate based on the transmitted first reference signals. The error matrix is indicative of an error of the first and second spatial filters in equalizing the MIMO radio channel. The method further comprises recomputing, for each of the at least one receive node in radio communication with the respective transmit node, the error matrix of the respective receive node; and updating the first spatial filter of the respective transmit node using the recomputed error matrix.

Spatial filtering technique

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 method for resource allocation in a wireless communication system, having a set of connected terminals, comprises allocating of transmission resources and assigning of transmission resources. The allocating in turn comprises estimating of a requirement value representing an amount of required transmission resources for satisfying a minimum quality of service during a next transmission time interval for respective connected terminal. An allocation subset is generated by including unsatisfied connected terminals so that the sum of the requirement values of the included connected terminals of the allocation subset equals available transmission resources. The generation of the allocation subset is performed by including connected terminals in an order according to the respective requirement values, starting with the lowest requirement value. The assigning of transmission resources is thereafter performed by assigning transmission resources of the next transmission time interval to connected terminals of the allocation subset.

Method and arrangement for resource allocation

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Fortaleza-CE, Brazil

Walter Cruz Freitas, Jr