Telefonaktiebolaget Lm Ericsson (publ)

Yuri C B Silva

Elvis M G Stancanelli

Arne Simonsson

Walter Cruz Freitas, Jr

Paulo G Normando

Francisco R P Cavalcanti

Gabor Fodor

Niklas Wernersson

Peter Larsson

Sara Sandberg

Francisco Rodrigo Porto Cavalcanti

Tarcisio Fereira Maciel

Walter Da Cruz Freitas, Jr

Darlan Cavalcante Moreira

Khaled Ardah

Carlos I R Bandeira

Pedro R S Lopes

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

A method in a network node for handling a transmission between a plurality of Transmission Points, TPs, and User Equipments, UEs, in a wireless network. The network node receives information from each respective UE out of a number of first UEs served by the network node, which information is related to the location of the UE. The network node then identifies a hot spot, based on the information received from the UEs. The hot spot is an area where the load density of UEs is above a first threshold. When a hot spot is defined the network node selects a plurality of TPs dedicated to serve the UEslocated in the hot spot and establishes a coordinated transmission mode from the plurality of dedicated TPs to the UEs located in the hot spot.

Coordinated transmission method for unbalanced load

A method performed by a network node for enabling Interference Alignment, IA, of transmissions to user equipments is provided. The network node receives signal strength values associated with more than one network node for the user equipments, wherein each signal strength value is associated with one network node. Then, the network node schedules a first group of the user equipments on radio transmission resources that are orthogonal to radio transmission resources of at least one other group of the user equipments when an IA gain value for each user equipment in the first group passes a threshold level. The IA gain value is determined by the network node based on the received signal strength values. The network node may then enable IA of transmissions to the scheduled first group of user equipments from at least two network nodes capable of performing IA of transmissions.

Network node and method for enabling interference alignment of transmissions to user equipments

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

Systems and methods provide for applying a clustering based assignment algorithm (CbAA) in a telecommunication system. A method includes: receiving strength information for transmission points belonging to an associated Coordinated Multi-Point (CoMP)-cell; determining the clustering subsets, wherein the step of determining the clustering subsets includes: applying a k-means algorithm to the strength information to form K clusters; identifying the cluster associated with each UE; associating a cluster to each transmission point in accordance to a pre-defined rule; and selecting the UEs to be serviced; and reporting the clustering formations.

Dynamic clustering for coordinated transmission in wireless communication systems

Improved amplify-and-forward relaying in a communication network is described, including an example network of multiple single-antenna mobile stations, a multi-antenna relay station, and a multi-antenna base station. Bi-directional communication with improved transmission efficiency is enabled by suitable transmit/receive processing at the relay station without drawbacks of current relaying techniques. Linear transmit and receive processing matrices are disclosed, and it is shown that the numbers of antennas at the relay station and the base station can be substantially the same without reducing network capacity, closely matching the performance for low and high signal to noise ratios of current techniques that require the relay station to have twice as many antennas as the base station.

Amplify-and-forward relaying in communication systems

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Fortaleza, Brazil

Yuri C B Silva