Modulation and coding scheme selection for link adaptation

A mobile device for use in a mobile communication network, the mobile device comprising:

• a transceiver module configured to receive multi-antenna downlink transmissions from the network;
• and
• a processing circuit configured to:
• determine whether to use an unrestricted set of Modulation and Coding Schemes (MCSs) or a restricted set of MCSs, where the unrestricted set of MCSs comprises all of a plurality of available MCSs, and the restricted set of MCSs comprises a subset of the plurality of available MCSs, wherein the processing circuit is configured to determine whether to use the unrestricted set of MCSs or the restricted set of MCSs by:
• determining whether the mobile communication network is sending dedicated pilots or reference signals to the mobile device for demodulation;
• in the event that dedicated pilots or reference signals are being transmitted, determining whether the dedicated pilots or reference signals are being transmitted with restrictions;
• in the event that the dedicated pilots or reference signals are not being transmitted with restrictions, determining that the unrestricted set of MCSs is to be used;
• and
• otherwise determining that the restricted set of MCSs is to be used;
• and
• use, according to said determination, either the restricted set of MCSs or the unrestricted set of MCSs to select the MCS to be used for performing link adaptation for the multi-antenna downlink transmission.

A method of operating a network node in a mobile communication network, the mobile communication network comprising a mobile device configured to receive a multi-antenna downlink transmission from the network node, the mobile device being configured to select a suitable Modulation and Coding Scheme (MCS) from a plurality of available MCSs for performing link adaptation for the multi-antenna downlink transmission, the method of operating the network node comprising:

• determining whether the mobile device is permitted to or should use a restricted set of MCSs for selecting the MCS to be used for performing link adaptation for the multi-antenna downlink transmission, the restricted set of MCSs comprising a subset of the plurality of available MCSs;
• and
• in the event that it is determined that the mobile device is permitted to use or should use the restricted set of MCSs when performing the link adaptation, indicating to the mobile device that it is permitted to use or should use the restricted set of MCSs when performing the link adaptation by transmitting dedicated pilots or references signals to the mobile device with restrictions;
• and
• otherwise transmitting the dedicated pilots or references signals to the mobile device without the restrictions, and thereby indicating to the mobile device to use the unrestricted set of MCSs when performing the link adaptation.

A network node for use in a mobile communication network, the mobile network comprising a mobile device configured to receive a multi-antenna downlink transmission from the network, the mobile device being configured to select a suitable Modulation and Coding Scheme (MCS) from a plurality of available MCSs for performing link adaptation for the multi-antenna downlink transmission, the network node comprising:

• a communication module for communicating with the mobile device;
• and
• a processing module configured to:
• determine whether the mobile device is permitted to or should use a restricted set of MCSs when performing link adaptation for the multi-antenna downlink transmission, the restricted set comprising a subset of the plurality of available MCSs;
• indicate to the mobile device, using the communication module, that the mobile device is permitted to use or should use the restricted set of MCSs when performing the link adaptation by transmitting dedicated pilots or references signals to the mobile device with restrictions the mobile device, in the event that the network node determines that the mobile device is permitted to or should use a restricted set of MCSs when performing the link adaptation;
• and
• otherwise transmit the dedicated pilots or references signals to the mobile device without the restrictions, and thereby indicate to the mobile device to use the unrestricted set of MCSs when performing the link adaptation.

A non-transitory computer readable medium storing a computer program comprising program instruction that, when executed by a processing circuit of a mobile device configuration for operation in a mobile communication network, configures the mobile device to:

• determine whether to use an unrestricted set of Modulation and Coding Schemes (MCSs) or a restricted set of MCSs, the unrestricted set of MCSs comprising all of a plurality of available MCSs and the restricted set comprising a subset of the plurality of available MCSs, wherein the determination is performed by:
• determining whether the mobile communication network is sending dedicated pilots or reference signals to the mobile device for demodulation;
• in the event that dedicated pilots or reference signals are being transmitted, determining whether the dedicated pilots or reference signals are being transmitted with restrictions;
• in the event that the dedicated pilots or reference signals are not being transmitted with restrictions, determining that the unrestricted set of MCSs is to be used;
• and
• otherwise determining that the restricted set of MCSs is to be used;
• and
• use, according to said determination, either the restricted set of MCSs or the unrestricted set of MCs to select the MCS to be used for performing link adaptation for a multi-antenna downlink transmission from the mobile communication network to the mobile device.