Interference mitigation

1. A control system for an optical wireless communications, OWC, network in which the OWC network comprises a plurality of access points for communicating with a plurality of endpoint devices via modulated light, the control system being configured to:

in response to receiving a report indicating a timeslot during which a first one of said access points detected an event indicative of interference, transmit an indication of said timeslot to at least one other access point;

wherein the indication causes said other access point to provide to the control system identifiers of the or each endpoint device that is registered with said other access point and was communicating with said other access point using said timeslot; and

in response to receiving an identifier of a single endpoint device from said other access points, determine the single endpoint device identified by said identifier as a cause of the interference experienced at the first access point; and

in response to receiving identifiers of plural endpoint devices from one or more of said other access points, cause said one or more other access points to instruct endpoint devices registered to said one or more other access points to advertise their presence.

2. The control system according to claim 1 , wherein the control system is configured to transmit an indication of said timeslot to a closest one or more of the other access points to the first access point.

3. The control system according to claim 1 , wherein the control system is configured to transmit an indication of said timeslot to at least one other access point physically located within a threshold distance of the first access point.

4. The control system according to claim 1 , wherein the control system is configured to transmit an indication of said timeslot to at least one other access point having more than a threshold overlapping coverage with the first access point.

5. The control system according to claim 1 , wherein the control system is configured to transmit an indication of said timeslot to all other access points in the same room of a building as the first access point.

6. The control system according to claim 1 , wherein the control system is configured to transmit an indication of said timeslot to all other access points in the OWC network.

7. The control system according to claim 1 , wherein the control system is configured to: in response to receiving a report from an endpoint device registered to one of the access points, indicating interference by at least one neighbour access point, cause the endpoint device to advertise its presence.

8. The control system according to claim 1 , implemented at the first access point.

9. The control system according to claim 1 , implemented in a distributed manner across a plurality of the access points.

10. A method performed by a control system of an optical wireless communications (OWC) network comprising a plurality of access points for communicating with a plurality of endpoint devices via modulated light, the method comprising:

receiving a report indicating a timeslot during which a first access point detected an event indicative of interference;

in response to receiving said report, transmitting an indication of said timeslot to at least one other access point;

wherein the receipt of the indication of said timeslot causes said other access point to provide to the control system identifiers of the or each endpoint device that is registered with said other access point and was communicating with said other access point using said timeslot;

in response to receiving an identifier of a single endpoint device from said other access point, determining the single neighbour endpoint device identified by said identifier as a cause of the interference experienced at the first access point; and

in response to receiving identifiers of plural neighbour endpoint devices from one or more of said other access points, causing said one or more other access points to instruct endpoint devices registered to the one or more other access points to advertise their presence.

11. A method according to claim 10 , comprising: in response to receiving a report from an endpoint device registered to one of the access points indicating interference by at least one neighbour access point, causing the endpoint device to advertise its presence.

12. An access point for an optical wireless communication (OWC) network for communicating with at least one endpoint device via modulated light, said access point being configured to:

receive, from a control system according to claim 1 , an indication of a timeslot during which another access point detected an event indicative of interference;

wherein the access point is configured to:

in response to receipt of said indication, determine an endpoint device that is registered to said access point and was communicating with said access point using said timeslot; and provide an identifier of said endpoint device to the control system.

13. A method performed by an access point of an optical wireless communication (OWC) network, the method comprising:

receiving, from a control system, an indication of a timeslot during which another access point detected an event indicative of interference;

wherein in response to receipt of the indication, determining an endpoint device that is registered to said access point and was communicating with the access point using said timeslot; and

providing an identifier of said endpoint device to the control system.

14. An optical wireless communication (OWC) system comprising the control system of claim 1 and the plurality of access points.