Communications device and method for adapting relaxed radio measurement procedure

1. A method of operating a communications device for communicating data via a wireless communications network, the method comprising:

detecting one or more of a plurality of beams of radio signals transmitted by the wireless communications network, the one or more of the plurality of beams of the radio signals which have been detected forming a set of one or more detected beams of radio signals from the one or more of the plurality of beams of radio signals transmitted from the wireless communications network,

identifying a sub-set of the set of one or more detected beams of radio signals which can be used to receive data carried by the radio signals of a beam for which the received signal strength of the radio signals of the beam exceeds a first evaluation threshold,

entering a relaxed radio measurement state in which the communications device reduces an amount of attempted measurements of the one or more of the plurality of beams of radio signals compared with a normal state according to one or more relaxed measurement state criteria, and when in the relaxed radio measurement state, determining a reference measurement level based on a signal strength of the radio signals of the sub-set of beams of radio signals,

determining a current measurement level based on a signal strength of the radio signals of the sub-set of beams of radio signals having a signal strength which exceeds the first evaluation threshold after determining the reference measurement level, and

determining whether the communications device should remain in the relaxed radio measurement state by comparing a difference between the reference measurement level and the current measurement level with a second delta threshold, wherein the second delta threshold is set dynamically by the communications device according to a number of the detected beams of the radio signals in the set of one or more detected beams of radio signals.

2. The method of claim 1 , the method comprising:

setting the second delta threshold to be a first value when the number of beams in the set of one or more detected beams of the radio signals is a first number; and

setting the second delta threshold to be a second value when the number of beams in the set of one or more detected beams of the radio signals is a second number, wherein

the first value is greater than the second value, and

the first number is lower than the second number.

3. The method of claim 2 , wherein the setting the second delta threshold comprises setting the second delta threshold as a reciprocal of the number of beams in the set of one or more detected beams of radio signals multiplied by a predetermined constant.

4. The method of claim 2 , wherein the setting the second delta threshold comprises setting the second delta threshold from a look-up table based on the number of beams in the set of one or more detected beams of radio signals.

5. The method of claim 1 , the method comprising:

setting the second delta threshold to be a first value when the number of beams in the set of one or more detected beams of the radio signals is a first number,

setting the second delta threshold to be a second value when the number of beams in the set of one or more detected beams of the radio signals is a second number, wherein

first value is greater than the second value, and

the first number is greater than the second number.

6. The method of claim 1 , wherein the setting the second delta threshold comprises setting the delta threshold according to conditions received from the wireless communications network.

7. The method of claim 1 , wherein the detecting the one or more of the plurality of beams of radio signals of the set comprises identifying one or more of the plurality of beams of radio signals transmitted by the wireless communications network which are in an active transmission configuration indicator state providing an indication of radio conditions of the one or more of the plurality of beams.

8. The method of claim 1 , wherein the detecting the one or more of the plurality of beams of radio signals transmitted by the wireless communications network comprises determining whether a received signal strength of radio signals transmitted in a beam with a beam indicator exceeds a third detection threshold.

9. The method of claim 1 , wherein each of the one or more of the plurality of beams of radio signals is transmitted periodically according to a time divided structure of a wireless access interface provided by the wireless communications network in at least one of different spatial directions and at different times.

10. The method of claim 1 , wherein the determining the reference measurement level comprises calculating an average value of the signal strength of the radio signals of the sub-set of the set of one or more detected beams of radio signals, and the determining the current measurement level comprises calculating the average value of the signal strength of the radio signals of the sub-set of the set of one or more detected beams of radio signals at a later time.

11. A communications device for communicating data via a wireless communications network, the communications device comprising:

transmitter circuitry configured to transmit signals via a wireless access interface provided by the wireless communications network,

receiver circuitry configured to receive signals transmitted via the wireless access interface, and

controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals, the controller circuitry being configured to control the receiver circuitry

to detect one or more of a plurality of beams of radio signals transmitted by the wireless communications network, the one or more of the plurality of beams of the radio signals which have been detected forming a set of one or more detected beams of radio signals from the one or more of the plurality of beams of radio signals transmitted from the wireless communications network,

to identify a sub-set of the set of one or more detected beams of radio signals which can be used to receive data carried by the radio signals of a beam for which the received signal strength of the radio signals exceeds a first evaluation threshold,

to enter a relaxed radio measurement state in which the communications device reduces an amount of attempted measurements of the one or more of the plurality of beams of radio signals compared with a normal state according to one or more relaxed measurement state criteria, and when in the relaxed radio measurement state, to determine a reference measurement level based on a signal strength of the radio signals of the sub-set of the set of one or more detected beams of radio signals,

to determine a current measurement level based on a signal strength of the radio signals of the sub-set of beams of radio signals having a signal strength which exceeds the first evaluation threshold after determining the reference measurement level, and

to determine whether the communications device should remain in the relaxed radio measurement state by comparing a difference between the reference measurement level and the current measurement level with a second delta threshold, wherein the second delta threshold is set dynamically by the communications device according to a number of the detected beams of the radio signals in the set of one or more detected beams of radio signals.

12. The communications device of claim 11 , wherein the controller circuitry is configured

to set the second delta threshold to be a first value when the number of beams in the set of one or more detected beams of the radio signals is a first number; and

to set the second delta threshold to be a second value when the number of beams in the set of one or more detected beams of the radio signals is a second number, wherein

the first value is greater than the second value, and

the first number is lower than the second number.

13. The communications device of claim 12 , wherein the controller circuitry is configured

to set the second delta threshold as a reciprocal of the number of beams in the set of the one or more detected beams of radio signals multiplied by a predetermined constant.

14. The communications device of claim 12 , wherein the controller circuitry is configured

to set the second delta threshold from a look-up table based on the number of beams in the set of one or more detected beams of radio signals.

15. Circuitry for a communications device comprising:

transmitter circuitry configured to transmit signals via a wireless access interface provided by the wireless communications network,

receiver circuitry configured to receive signals transmitted via the wireless access interface, and

controller circuitry configured to control the transmitter circuitry and the receiver circuitry to transmit or to receive the signals, the controller circuitry being configured to control the receiver circuitry

to detect one or more of a plurality of beams of radio signals transmitted by the wireless communications network, the one or more of the plurality of beams of the radio signals which have been detected forming a set of one or more detected beams of radio signals from the one or more of the plurality of beams of radio signals transmitted from the wireless communications network,

to identify a sub-set of the set of one or more detected beams of radio signals which can be used to receive data carried by the radio signals of a beam for which the received signal strength of the radio signals exceeds a first evaluation threshold,

to enter a relaxed radio measurement state in which the communications device reduces an amount of attempted measurements of the plurality of beams of radio signals compared with a normal state according to one or more relaxed measurement state criteria, and when in the relaxed radio measurement state, to determine a reference measurement level based on a signal strength of the radio signals of the sub-set of the set of more or more detected beams of radio signals,

to determine a current measurement level based on a signal strength of the radio signals of the sub-set of beams of radio signals after determining the reference measurement level, and

to determine whether the communications device should remain in the relaxed radio measurement state by comparing a difference between the reference measurement level and the current measurement level with a second delta threshold, wherein the second delta threshold is set dynamically by the communications device according to a number of the detected beams of the radio signals in the set of one or more detected beams of radio signals.