Reduction of CRC field in compact DCI message on M-PDCCH for low cost MTC devices

A terminal device for use in a wireless telecommunications system, the terminal device comprising:

• a receiver;
• a transmitter;
• and
• processing circuitry, wherein
• the receiver is configured to:
• receive a first control message from a base station, the first control message indicating a radio resource for use by at least one of the receiver and transmitter to exchange a signal with the base station and the first control message comprising a code generated on the basis of an identifier of an intended terminal device and a value of a time-dependent parameter at a transmission time of the first control message, the intended terminal device being a terminal device intended for exchanging the signal with the base station;
• the processing circuitry is configured to:
• attempt to perform a predetermined process using the code of the first control message, an identifier of the terminal device and the value of the time-dependant parameter at the transmission time of the first control message,
• the first control message comprises a downlink control information (DCI) message for indicating the radio resource, and the code of the first control message is appended to the DCI message, the code comprising a cyclic redundancy code (CRC) generated on the basis of the DCI message which has been XOR-ed with a hash generated on the basis of the identifier of the intended terminal device and the value of the time-dependent parameter at the transmission time of the first control message,
• the predetermined process attempted using the code comprises:
• generating a hash on the basis of the identifier of the terminal device and the value of the time-dependent parameter at the transmission time of the first control message;
• XOR-ing the previously XOR-ed CRC with the generated hash;
• and
• attempting a decode operation on the CRC, and
• the processing circuitry is further configured to:
• if the decode operation of the CRC is successful, determine the predetermined process to have been successfully completed;
• if the decode operation of the CRC is not successful, determine the predetermined process not to have been successfully completed;
• if the predetermined process is determined not to have been successfully completed, disregard the first control message;
• and
• if the predetermined process is determined to have been successfully completed, control at least one of the receiver and transmitter to exchange a signal with the base station using the radio resource indicated by the first control message.

A terminal device for use in a wireless telecommunications system, the terminal device comprising:

• a receiver;
• a transmitter;
• and
• processing circuitry, wherein
• the receiver is configured to:
• receive a first control message from a base station, the first control message indicating a radio resource for use by at least one of the receiver and transmitter to exchange a signal with the base station and the first control message comprising a code generated on the basis of an identifier of an intended terminal device and a value of a time-dependent parameter at a transmission time of the first control message, the intended terminal device being a terminal device intended for exchanging the signal with the base station;
• the processing circuitry is configured to:
• attempt to perform a predetermined process using the code of the first control message, an identifier of the terminal device and the value of the time-dependant parameter at the transmission time of the first control message,
• the first control message comprises a downlink control information (DCI) message for indicating the radio resource, and the code of the first control message is appended to the DCI message, the code comprising a cyclic redundancy code (CRC) generated on the basis of a concatenated bit stream comprising the DCI message, the value of the time-dependent parameter at the transmission time of the first control message and the identifier of the intended terminal device,
• the predetermined process attempted using the code comprises:
• generating a concatenated bit stream comprising the DCI message, the value of the time-dependent parameter at the transmission time of the first control message and the identifier of the terminal device;
• calculating a CRC on the basis of the generated concatenated bit stream;
• and
• comparing the calculated CRC with the CRC appended to the DCI message, and
• the processing circuitry is further configured to:
• if the calculated CRC and the CRC appended to the DCI message match, determine the predetermined process to have been successfully completed;
• if the calculated CRC and the CRC appended to the DCI message do not match, determine the predetermined process not to have been successfully completed;
• if the predetermined process is determined not to have been successfully completed, disregard the first control message;
• and
• if the predetermined process is determined to have been successfully completed, control at least one of the receiver and transmitter to exchange a signal with the base station using the radio resource indicated by the first control message.

A terminal device for use in a wireless telecommunications system, the terminal device comprising:

• a receiver;
• a transmitter;
• and
• processing circuitry, wherein
• the receiver is configured to:
• receive a first control message from a base station, the first control message indicating a radio resource for use by at least one of the receiver and transmitter to exchange a signal with the base station and the first control message comprising a code generated on the basis of an identifier of an intended terminal device and a value of a time-dependent parameter at a transmission time of the first control message, the intended terminal device being a terminal device intended for exchanging the signal with the base station;
• the processing circuitry is configured to:
• attempt to perform a predetermined process using the code of the first control message, an identifier of the terminal device and the value of the time-dependant parameter at the transmission time of the first control message,
• the first control message comprises a downlink control information (DCI) message for indicating the radio resource, and the code of the first control message is appended to the DCI message, the code comprising a hash generated on the basis of the identifier of the intended terminal device, the value of the time-dependent parameter at the transmission time of the first control message and a cyclic redundancy code (CRC) generated on the basis of the DCI message,
• the predetermined process attempted using the code comprises:
• calculating a CRC on the basis of the DCI message;
• generating a hash on the basis of the identifier of the terminal device, the value of the time-dependent parameter at the transmission time of the first control message and the generated CRC;
• and
• comparing the generated hash with the hash appended to the DCI message, and
• the processing circuitry is further configured to:
• if the generated hash and the hash appended to the DCI message match, determine the predetermined process to have been successfully completed;
• if the generated hash and the hash appended to the DCI message do not match, determine the predetermined process not to have been successfully completed;
• if the predetermined process is determined not to have been successfully completed, disregard the first control message;
• and
• if the predetermined process is determined to have been successfully completed, control at least one of the receiver and transmitter to exchange a signal with the base station using the radio resource indicated by the first control message.