Reducing interference in a communications network

1 . A computer implemented method for reducing interference experienced at a first frequency due to transmissions made at one or more of a plurality of candidate frequencies, the method comprising:

i) dividing the candidate frequencies into a first subset of candidate frequencies and a second subset of candidate frequencies;

ii) blanking the first subset of candidate frequencies; and

iii) determining whether the interference experienced at the first frequency is due to transmissions made on the first subset of candidate frequencies, dependent on whether said interference is reduced as a result of blanking the first subset of candidate frequencies.

2 . The method of claim 1 wherein step iii) comprises: determining that the interference experienced at the first frequency is due to transmissions made on the first subset of candidate frequencies if the interference experienced at the first frequency is reduced as a result of blanking the first subset of candidate frequencies.

3 . The method of claim 1 wherein step iii) comprises: determining that the interference experienced at the first frequency is not due to transmissions made on the first subset of candidate frequencies if the interference experienced at the first frequency is not reduced as a result of blanking the first subset of candidate frequencies.

4 . The method of claim 3 further comprising:

determining that the interference experienced at the first frequency is due to transmissions made on the second subset of candidate frequencies; and

repeating steps i), ii) and iii) for third and fourth subsets of the second subset of candidate frequencies.

5 . The method of claim 4 further comprising repeating steps i), ii) and iii) in an iterative manner for subsequent subsets of candidate frequencies until one or more individual frequencies causing the interference are determined.

6 . The method of claim 5 further comprising:

using a noise cancellation process to cancel the interference experienced at the first frequency due to the determined one or more individual frequencies.

7 . The method of claim 4 further comprising repeating steps i), ii) and iii) in an iterative manner for subsequent subsets of candidate frequencies until all frequencies in the plurality of candidate frequencies have been eliminated.

8 . The method of claim 7 further comprising determining to use a different frequency to the first frequency.

9 . The method of claim 1 wherein the plurality of candidate frequencies comprises frequencies that are historically known to cause interference on the first frequency.

10 . The method of claim 1 wherein the plurality of candidate frequencies comprises a frequency range; and wherein the first subset of frequencies comprises a first portion of the frequency range and the second subset of frequencies comprises a second portion of the frequency range.

11 . The method of claim 1 wherein step i) comprises dividing an ordered list of the plurality of candidate frequencies in half and wherein the first subset of candidate frequencies correspond to the first half of the ordered list of the plurality of candidate frequencies and the second subset of candidate frequencies correspond to the second half of the ordered list of the plurality of candidate frequencies.

12 . The method of claim 1 wherein the method is performed by a node in a communications network and wherein the method is for use in determining which of a plurality of candidate downlink radio frequencies are causing Passive Intermodulation, PIM, at a first uplink radio frequency.

13 . The method of claim 12 wherein the method comprises determining that the PIM is caused by the one of more individual downlink frequencies; and

using different downlink frequencies for subsequent transmissions.

14 . The method of claim 12 wherein the method comprises determining that the PIM is caused by an environment and that a different uplink frequency should be used.

15 . The method of claim 12 wherein the plurality of candidate frequencies comprise frequencies being used for downlink transmissions by an operator of the node.

16 . The method of claim 1 wherein the method is performed by a hearing aid and wherein the method is for use in determining which ambient sound frequencies from a plurality of candidate sound frequencies are causing interference at a first sound frequency of interest to a user of the hearing aid.

17 . The method of claim 1 wherein the method is performed by a first Internet of things, IoT, device, transmitting on a first frequency and wherein the candidate frequencies are transmission frequencies used by other IoT devices in an environment of the first IoT device.

18 . A computing apparatus for reducing interference experienced at a first frequency due to transmissions made at one or more of a plurality of candidate frequencies wherein the computing apparatus is adapted to:

i) divide the candidate frequencies into a first subset of candidate frequencies and a second subset of candidate frequencies;

ii) blank the first subset of candidate frequencies; and

iii) determine whether the interference experienced at the first frequency is due to transmissions made on the first subset of candidate frequencies, dependent on whether said interference is reduced as a result of blanking the first subset of candidate frequencies.

19 . The computing apparatus of claim 18 wherein determining that the interference experienced at the first frequency is due to transmissions made on the first subset of candidate frequencies if the interference experienced at the first frequency is reduced as a result of blanking the first subset of candidate frequencies.

20 . An apparatus for reducing interference experienced at a first frequency due to transmissions made at one or more of a plurality of candidate frequencies, the apparatus comprising:

a memory comprising instruction data representing a set of instructions; and

a processor configured to communicate with the memory and to execute the set of instructions, wherein the set of instructions, when executed by the processor, cause the processor to:

i) divide the candidate frequencies into a first subset of candidate frequencies and a second subset of candidate frequencies;

ii) blank the first subset of candidate frequencies; and

iii) determine whether the interference experienced at the first frequency is due to transmissions made on the first subset of candidate frequencies, dependent on whether said interference is reduced as a result of blanking the first subset of candidate frequencies.