Fast handover for an optical multi-cell communication system
A method and apparatus for use in an optical wireless communication system that enable communication of data, e.g. LiFi, and wherein fast handover can be achieved by having neighboring access points (AP1, AP2) announce themselves using very short frames, that get picked up by user devices (EP1) that detect the identity of a neighbor access point (AP2) and then communicate this to the current access point (AP1) to share information on the user device (EP1) with its neighbor access point (AP2), so that the neighbor access point (AP2) can be pre-configured to allocate resources and/or synchronize.
1. An apparatus for fast handover in an optical multi-cell communication system for use in an access point, the apparatus being configured for:
advertising presence of the access point in an optical multi-cell communication system by transmitting shortened frames without a payload portion in an allocated pre-defined part of a common channel of a frame cycle of a link layer or physical layer protocol, wherein the shortened frame contains an identifier of the advertising access point;
pre-registering an end point,
reserving transmission resources of the access point for the end point, and
transmitting an acceptance message which includes timing information of the reserved transmission resources and an endpoint identifier to the end point, in response to a pre-registration request received from the end point.
2. The apparatus of claim 1 , wherein the apparatus is configured for transmitting the shortened frame in every frame cycle.
3. The apparatus of claim 1 , wherein the apparatus is configured for transmitting the shortened frame in the common channel and a default frame for medium access planning followed by an active frame for medium access planning in a different channel of the frame cycle.
4. The apparatus of claim 1 , wherein the apparatus is configured for:
prioritizing reservation of resources by allocating a higher priority to end points already registered at the access point and to non-registered end points requesting entry in a domain of the access point and a lower priority to a pre-registrations of end points, and wherein a higher priority is allocated to a newer pre-registration request than to an older pre-registration request.
5. The apparatus of claim 1 , wherein the acceptance message comprises an endpoint identifier of the end point assigned by the access point.
6. The apparatus of claim 1 , wherein the apparatus is configured for removing the pre-registration of the end point at the access point after a predetermined time period.
7. The apparatus of claim 1 , wherein the apparatus is configured for prioritizing reservation of transmission resources by allocating a higher priority to end points already registered at the access point and to non-registered end points requesting entry in a domain of the access point and a lower priority to a pre-registrations of end points, wherein a higher priority is allocated to a newer pre-registration request than to an older pre-registration request.
8. The apparatus of claim 1 , wherein the shortened frame is restricted to a preamble and a header which contains an identifier of the advertising access point.
9. The apparatus of claim 1 , wherein the common channel of the shortened frame is separated from normal data traffic in the frame cycle.
10. An access point for providing access to an optical multi-cell communication system, the access point comprising an apparatus as claimed in claim 1 .
11. A luminaire for an illumination system, the luminaire comprising at least one access point as claimed in claim 10 .
12. A system for fast handover in an optical multi-cell communication system, comprising:
a plurality of access points according to claim 10 .
13. A method of allowing a fast handover in an optical multi-cell communication system by an access point, the method comprising the access point:
advertising presence of the access point in an optical multi-cell communication system by transmitting shortened frames without a payload portion in an allocated pre-defined part of a common channel of a frame cycle of a link layer or physical layer protocol, wherein the shortened frame contains an identifier of the advertising access point
pre-registering an end point,
reserving transmission resources of the access point for the end point, and
transmitting an acceptance message which includes timing information of the reserved transmission resources and an endpoint identifier to the end point, in response to a pre-registration request received from the end point.
14. The method of claim 13 , the method comprising the access point:
prioritizing reservation of resources by allocating a higher priority to end points already registered at the access point and to non-registered end points requesting entry in a domain of the access point and a lower priority to a pre-registrations of end points, and wherein a higher priority is allocated to a newer pre-registration request than to an older pre-registration request.
15. A non transitory computer readable medium comprising instructions for performing the method of claim 13 when run on a computer device of an access point.