First network node, second network node, central network node and methods performed thereby for handling data

A computer-implemented method, performed by a second network node, for handling data, the second network node operating in a communications network, the method comprising:

• applying a Kalman filter of a second type to two respective third sets of filtered data (ŝ(1), ŝ(2)) respectively received from each of two third network nodes operating in the communications network, the applying being performed using respective third covariance matrices (P(1), P(2)), wherein the applying of the Kalman filter of the second type outputs a first set of filtered data (ŝ(1∪2)), and a first covariance matrix (P(1∪2)), and
• providing, in an uplink direction, the first set of filtered data (ŝ(1∪2)) and the first covariance matrix (P(1∪2)) to one of:
• a) the second network node for further processing, b) a first network node, and c) a central network node.

A computer-implemented method, performed by a central network node, for handling data, the central network node operating in a communications network, the method comprising:

• receiving from a first network node operating in the communications network, a second set of filtered data (ŝ) and a second covariance matrix (P), the second set of filtered data ({right arrow over (s)}) and the second covariance matrix (P) having been obtained by having applied a Kalman filter of a first type to a first aggregation of a first set of measurements (yl) collected via a first plurality of antenna elements managed by the first network node and a first set of filtered data (ŝ0) received from a second network node, and
• detecting one or more first radio signals (sK) based on the second set of filtered data (ŝ) and the second covariance matrix (P).

A first network node, for handling data, the first network node being configured to operate in a communications network, the first network node comprising processing circuitry and a memory that contains instructions executable by the processing circuitry whereby the first network node is configured to:

• apply a Kalman filter of a first type to a first aggregation of a first set of measurements (yl) configured to be collected via a first plurality of antenna elements configured to be managed by the first network node, and a first set of filtered data (ŝ0) configured to be received from a second network node, using a first covariance matrix (P0), wherein the applying of the Kalman filter () of the first type is configured to output a second set of filtered data (ŝ), and a second covariance matrix (P), and
• send, in an uplink direction, the second set of filtered data (ŝ) and the second covariance matrix (P) to one of:
• another network node subsequently adjacent to the first network node towards a central network node, and the central network node.