Network Node and Method in a Wireless Telecommunications Network

A method, performed by a network node, for managing a transmission of one or more Cell-specific Reference Signals (CRS) subframes, wherein the network node operates one or more cells, the method comprising:

• identifying if a cell out of the one or more cells is actively serving a set of User Equipment (UEs) or not;
• when the cell is not actively serving a set of UEs:
• sending CRS over a first bandwidth in one or more CRS subframes which are transmitted during a paging occasion and/or in one or more CRS subframes where system information is sent;
• sending CRS over a second bandwidth in one or more CRS subframes which are not transmitted during a paging occasion and/or in one or more CRS subframes except subframes where system information is sent;
• when the cell is actively serving a set of UEs, the set of UEs being configured for Discontinuous Reception (DRX):
• sending CRS over the first bandwidth in one or more CRS subframes which are transmitted in the cell during an onDuration interval of the DRX pattern and/or in the one or more CRS subframes where system information is sent and/or in one or more CRS subframes where downlink (DL) data is sent;
• sending CRS over the second bandwidth, in CRS subframes which are not transmitted in the cell during the onDuration interval of the DRX and/or in the one or more CRS subframes except CRS subframes where system information is sent and/or in the one or more CRS subframes except CRS subframes where DL data is sent;
• wherein the second bandwidth is reduced in relation to the first bandwidth.

A network node for managing transmission of Cell Reference Signals (CRS) wherein the network node is configured to operate one or more cells, the network node comprising:

• processing circuitry;
• memory containing instructions executable by the processing circuitry whereby the network node is operative to:
• identify if a cell is actively serving a set of User Equipment (UEs) or not;
• when the cell is not actively serving a set of UEs:
• send CRS over a first bandwidth in one or more CRS subframes which are transmitted during a paging occasion and/or on CRS subframes where system information is sent;
• send CRS over a second bandwidth in one or more CRS subframes which are not transmitted during a paging occasion and/or in CRS subframes except CRS subframes where system information is sent;
• when the cell is actively serving a set of UEs, the set of UEs being configured for Discontinuous Reception (DRX):
• send CRS over the first bandwidth in one or more CRS subframes which are transmitted in the cell during an onDuration interval of a DRX pattern and/or in CRS subframes system information is sent and/or in CRS subframes where downlink (DL) data is sent;
• send CRS over the second bandwidth, in CRS subframes which are not transmitted in the cell during an onDuration interval of the DRX pattern and/or in CRS subframes except CRS subframes where system information is sent and/or on CRS subframes except CRS subframes where DL data is sent;
• wherein the second bandwidth is reduced in relation to the first bandwidth.