Infrastructure equipment, communications devices and methods for compensating for frequency drift of an oscillator of a communications device

An infrastructure equipment forming part of a mobile communications network configured to transmit signals to and receive signals from one or more communications devices, the infrastructure equipment comprising

• a receiver configured to receive signals on the uplink from the one or more communications devices via a wireless access interface of the mobile communications network,
• a transmitter configured to transmit signals on the downlink to the one or more communications devices via the wireless access interface, and
• a controller configured to control the receiver to receive the signals and to control the transmitter to transmit the signals, wherein the controller is configured in combination with the receiver and the transmitter
• to receive uplink signals transmitted from one of the communications devices in a plurality of transmission periods, each of the plurality of transmission periods being separated from a next transmission by a first predetermined period in which the one of the communications devices receives
• downlink signals from the infrastructure equipment to correct a transmission frequency with respect to a carrier frequency of allocated communications resources, and
• after a last of the transmission periods in which the uplink signals are received from the one of the communications devices, to determine whether the duration of reception of the signals from the one of the communications devices in the last of the transmission periods exceeded the predetermined threshold, and if so to control the transmitter
• to delay transmission of signals to the one of the communications devices for a second predetermined period following the reception of the signals from the one of the communications devices.

A method of controlling communications at a communications device configured to transmit signals to and receive signals from an infrastructure equipment forming part of a mobile communications network, the method comprising

• transmitting via a wireless access interface of the mobile communications network the signals to the infrastructure equipment in accordance with a controlled output frequency in a plurality of transmission periods, each of the plurality of transmission periods being separated from a next transmission by a first predetermined period in which the communications device receives downlink signals from the infrastructure equipment, and in which the communications device can correct the output frequency for transmitting the signals with respect to a carrier frequency of the infrastructure equipment, and after transmitting the signals in a last of the transmission periods,
• determining whether the transmission duration in the last transmission period exceeded the predetermined threshold, and if so subsequently
• correcting the output frequency to the carrier frequency of the infrastructure equipment during a second predetermined period, and
• decoding, subsequent to the second predetermined period, signals received from the infrastructure equipment.