Securing a connection in a radio system

A system, comprising:

• a base transceiver station including an antenna array including a plurality of antenna elements configured to transmit at least one beam specific pilot;
• and
• at least one terminal device configured to use the pilot in channel estimation, wherein
• the base transceiver station is configured to determine a calibration quality indicator describing the quality of calibration of the antenna array;
• the base transceiver station is configured to check whether the determined calibration quality indicator resides below a calibration quality threshold value, the calibration quality threshold value being a predetermined value;
• and
• the base transceiver station and the terminal device are configured to use an antenna element specific pilot when the calibration quality indicator resides below the calibration quality threshold value.

A system, comprising:

• a base transceiver station including an array including a plurality of elements configured to transmit at least one beam specific pilot;
• and
• at least one terminal device configured to use the pilot in channel estimation, wherein
• the base transceiver station is configured to determine a calibration quality indicator describing the quality of calibration of an element array;
• the base transceiver station is configured to check whether the determined calibration quality indicator resides below a calibration quality threshold value, the calibration quality threshold value being a predetermined value;
• and
• the base transceiver station and the terminal device are configured to use an element specific pilot when the calibration quality indicator resides below the calibration quality threshold value.

An apparatus, comprising:

• a processor configured to
• use a beam specific pilot for transmitting using a plurality of antenna elements of an antenna array of a base transceiver station;
• determine a calibration quality indicator describing the quality of calibration of the antenna element array;
• check whether the determined calibration quality indicator resides below a calibration quality threshold value, the calibration quality threshold value being a predetermined value;
• and
• use an antenna element specific pilot when the calibration quality indicator resides below the calibration quality threshold value.

An apparatus, comprising:

• a first using means for using a beam specific pilot for transmitting using a plurality of antenna element means of an antenna array of a base transceiver station:
• a determining means for determining a calibration quality indicator describing the quality of calibration of the antenna element means for transmitting and receiving signals;
• a checking means for checking whether the determined calibration quality indicator resides below a calibration quality threshold value, the calibration quality threshold value being a predetermined value;
• and
• a second using means for using an antenna element means specific pilot when the calibration quality indicator resides below the calibration quality threshold value.

A method, comprising:

• using a beam specific pilot for transmitting using a plurality of antenna elements of an antenna array of a base transceiver station;
• determining a calibration quality indicator describing the quality of calibration of the antenna element array;
• checking whether the determined calibration quality indicator resides below a calibration quality threshold value, the calibration quality threshold value being a predetermined value;
• and
• using an antenna element specific pilot when the calibration quality indicator resides below the calibration quality threshold value.

A computer program embodied on a computer-readable medium, the computer program configured to control a processor to perform operations comprising:

• using a beam specific pilot for transmitting using a plurality of antenna elements of an antenna array of a base transceiver station;
• determining a calibration quality indicator describing the quality of calibration of the antenna element array;
• checking whether the determined calibration quality indicator resides below a calibration quality threshold value, the calibration quality threshold value being a predetermined value;
• and
• using an antenna element specific pilot when the calibration quality indicator resides below the calibration quality threshold value.