Robust transmission on downlink discontinuous transmission carrier

A base station for downlink discontinuous transmission, the base station comprising:

• a memory configured to store a common reference symbol, CRS and transmission mode configuration information;
• a transmitter configured to transmit data and CRS discontinuously in sub frames in accordance with a selected transmission mode, the discontinuous transmission omitting transmission of data and CRS in specified sub frames;
• and
• a processor configured to;
• select a transmission mode from a plurality of transmission modes that include at least one of a transmit diversity mode and an open loop multiple-input-multiple-output, MIMO, mode;
• and
• include in the discontinuous transmission at least one CRS, the CRS being transmitted in only a pre-determined subset of the sub frames and in additional sub frames where there is transmission of data using a selected transmission mode.

A method at a user equipment, UE, for reception of discontinuous transmission from a base station, the method comprising:

• storing common reference symbols, CRS, and transmission mode configuration information, a transmission mode being selected from a plurality of transmission modes that include at least one of a transmit diversity mode and an open loop multiple-input-multiple-output, MIMO, mode;
• receiving discontinuous transmissions that include the stored CRS in a selected subset of sub frames;
• and
• performing channel estimation based on one of CRS and channel state information symbols, CSI-RS.

A user equipment, UE, for reception of discontinuous transmissions from a base station, the UE comprising:

• a memory configured to store common reference symbols, CRS, and transmission mode configuration information, a transmission mode being selected from a plurality of transmission modes that include at least one of a transmit diversity mode and an open loop multiple-input-multiple-output, MIMO, mode;
• a receiver configured to receive discontinuous transmissions, the discontinuous transmissions including the stored CRS in a selected subset of sub frames;
• and
• a processor configured to perform channel estimation based on one of CRS and channel state information reference symbols, CSI-RS.