Communications device, infrastructure equipment, wireless communications network and methods
A user terminal configured to perform communication with an infrastructure equipment of a mobile communications network. The user terminal including a receiver configured to receive signals transmitted by the infrastructure equipment in accordance with a wireless access interface and a transmitter configured to transmit signals to the infrastructure equipment in accordance with the wireless access interface. The user terminal is configured to receive an indication on a downlink of the wireless access interface of one of a plurality of different subcarrier spacing which the communications device should use to transmit or to receive the signals representing the data.
1. A communications device configured to transmit signals to and/or receive signals from an infrastructure equipment of a mobile communications network, the communications device comprising
a receiver configured to receive signals transmitted by the infrastructure equipment in accordance with a wireless access interface,
a transmitter configured to transmit signals to the infrastructure equipment in accordance with the wireless access interface, and
a controller configured to control the transmitter and the receiver to transmit data to the infrastructure equipment via an uplink of the wireless access interface or to receive data on the downlink of the wireless access interface, wherein the wireless access interface can provide a plurality of different spacing of subcarriers for transmitting signals representing the data on the uplink or for receiving the signals representing the data on the downlink, and the controller is configured in a combination with the transmitter and the receiver
when the infrastructure equipment identifies a requirement to provide communications resources of the wireless access interface on the uplink for the communications device to transmit data to the infrastructure equipment or on the downlink for the communications device to receive data from the infrastructure equipment, to receive an indication on a downlink of the wireless access interface of one of the plurality of different subcarrier spacing which the communications device should use to transmit or to receive the signals representing the data, the indicated subcarrier spacing also determining whether the communications device should use a single subcarrier or multiple subcarriers.
2. A communications device as claimed in claim 1 , wherein the receiver is configured to receive from the infrastructure equipment an indication of which of the subcarriers of a plurality of available subcarriers, with the indicated subcarrier spacing, the communications device should use to transmit the data to the infrastructure equipment or to receive the data from the infrastructure equipment or which plurality of available subcarriers, with the indicated subcarrier spacing, the communications device should use to transmit or to receive the data, depending on the indicated subcarrier spacing.
3. A communications device as claimed in claim 2 , wherein the receiver is configured to receive the indication of the subcarrier spacing with the indication of the subcarrier or multiple subcarriers to use in a downlink control message comprising a field indicating the subcarrier spacing and a field indicating the subcarrier or multiple subcarriers to use, and the controller is configured to interpret differently the field indicating which of the subcarrier or multiple subcarriers to use depending upon whether the field indicating the subcarrier spacing indicates a subcarrier spacing which can only be used as a single subcarrier or a subcarrier spacing which can be used as a single or multiple subcarriers.
4. A communications device as claimed in claim 3 , wherein the field indicating which of the subcarrier or multiple subcarriers to use as a function of the subcarrier spacing is predetermined between the infrastructure equipment and the communications device, which can be represented as a table.
5. A communications device as claimed in claim 4 , wherein the predetermined interpretation of the field indicating which of the subcarrier or multiple subcarriers to use as a function of the subcarrier spacing is received from the infrastructure equipment as part of broadcast system information.
6. A communications device as claimed in claim 3 , wherein the downlink control message includes an indication of one or more of a modulation scheme to be used, a coding scheme to be used and a transport block size to be used by the communications device when transmitting the data, and the controller is configured to interpret the indication of one or more of the modulation scheme, the coding scheme and the transport block size to use differently depending on the indicated subcarrier spacing.
7. A communications device as claimed in claim 6 , wherein the different interpretation of the indication of one or more of the modulation scheme, the coding scheme and the transport block size depending on the indicated subcarrier spacing is received from the infrastructure equipment as part of broadcast system information.
8. A communications device as claimed in claim 3 , wherein the downlink control message is transmitted as part of a random access procedure.
9. A communications device as claimed in claim 1 , wherein the controller is configured with the transmitter and the receiver
to measure a strength of signals received from the infrastructure equipment via the wireless access interface, and
to transmit a report of the measurements to the infrastructure equipment, the infrastructure equipment selecting the subcarrier spacing for the communications device based on the received measurement report.
10. A communications device as claimed in claim 1 , wherein the plurality of different spacing of the subcarriers comprises two subcarrier spacing of 3.75 kHz and 15 kHz, and the indication of the 3.75 kHz subcarrier spacing indicates that the communications device should transmit the signals representing the data or receive the signals representing the data on a single subcarrier, and the indication of the 15 kHz subcarrier indicates that the communications device should transmit the signals representing the data or receive the signals representing the data on a single subcarrier or multiple subcarriers.
11. A communications device configured to transmit signals to and/or receive signals from an infrastructure equipment of a mobile communications network, the communications device comprising
a receiver configured to receive signals transmitted by the infrastructure equipment in accordance with a wireless access interface,
a transmitter configured to transmit signals to the infrastructure equipment in accordance with the wireless access interface, and
a controller configured to control the transmitter and the receiver to transmit data to the infrastructure equipment via an uplink of the wireless access interface or to receive data on the downlink of the wireless access interface, wherein the wireless access interface can provide a plurality of different spacing of subcarriers for transmitting signals representing the data on the uplink or for receiving the signals representing the data on the downlink, and the controller is configured in a combination with the transmitter and the receiver
to select one of a predetermined set of preambles to represent a subcarrier spacing requested by the communications device and a request for a single subcarrier or for multiple subcarriers,
to transmit as part of a random access procedure the preamble to the infrastructure equipment representing the requested carrier spacing, and
to configured one of the transmitter to transmit the data on the uplink or the receiver to receive the data on the downlink in accordance with the requested subcarrier spacing.
12. A communications device as claimed in claim 11 , wherein the controller is configured to select one of the predetermined set of preambles to represent the requested subcarrier spacing and a request for a single subcarrier or for multiple subcarriers depending on the subcarrier spacing requested.
13. A communications device as claimed in claim 11 , wherein the controller is configured with the transmitter and the receiver
to receive a downlink control message allocating communications resources of the uplink or the downlink, the downlink control message including a field indicating frequency resources allocated by the infrastructure equipment on the uplink or the downlink, the controller being configured to interpret differently the field indicating the frequency resources allocated by the infrastructure equipment according to the subcarrier spacing requested by the communications device.
14. A communications device as claimed in claim 11 , wherein the controller is configured with the transmitter and the receiver
to measure a strength of signals received from the infrastructure equipment via the wireless access interface, and
to identify the requested subcarrier spacing base on the strength of the signals received from the infrastructure equipment.
15. A communications device as claimed in claim 11 , wherein the plurality of different spacing of the subcarriers comprises two subcarrier spacing of 3.75 kHz and 15 kHz, and the indication of the 3.75 kHz subcarrier spacing indicates that the communications device should transmit the signals representing the data or receive the signals representing the data on a single subcarrier, and the indication of the 15 kHz subcarrier indicates that the communications device should transmit the signals representing the data or receive the signals representing the data on a single subcarrier or multiple subcarriers.