Methods and apparatus for efficient joint power line and visible light communication
A hybrid communications system implements different communication technologies to communicate data and information for particular communications directions in different portions of the system. Power line communications (PLC) signaling is used to deliver data and information from a gateway device to a light access point. Visible light communications (VLC) signaling is used to communicate data and information from the light access point to a user equipment (UE) device. Wireless radio signaling, wireless infrared (IR) signaling, or a combination of wireless IR signaling and PLC signaling is used to communicate data/information from the UE device to the gateway device. To efficiently control the VLC communications channel between the light access point and UE device, the UE device measures the VLC channel, e.g., calculating SNRs on a per VLC tone basis, and communicating VLC channel quality feedback information to the gateway device, which is forwarded to the light access point.
1. A method of operating user equipment (UE) device, comprising:
receiving a light signal from an access point communicating information to the UE, said light signal including at least some data from a gateway device which supplied said data to the access point via a power line communications link; and
communicating feedback information from said UE device to the gateway device via a communications channel which includes a wireless uplink, said feedback information communicating visible light communications (VLC) channel quality information and including a suggested modulation constellation size or suggested coding rate to be used by the access point during future VLC transmissions, said feedback information based at least in part on measurements made by the UE of the received light signal.
2. The method of claim 1 , wherein the channel quality information provides information on the quality of a light channel used to communicate said light signal from the access point to the UE device.
3. The method of claim 1 , further comprising:
performing a signal to noise ratio (SNR) estimate for a VLC modulation carrier based on a received pilot signal included in said light signal.
4. The method of claim 3 , wherein said feedback information includes SNR information on a per light channel modulation carrier basis for each of a plurality of light channel modulation carriers used to communicate said light signal.
5. The method of claim 1 , wherein the measurements made by the UE of the received light signal are for a previous communication between the access point and the UE.
6. The method of claim 1 , wherein the feedback information further comprises power line channel quality information.
7. The method of claim 1 , wherein the measurements are based on VLC pilot signals or traffic data signals received by the UE.
8. The method of claim 1 , wherein the wireless uplink comprises wireless radio signaling or wireless infrared signaling.
9. A user equipment (UE) device, comprising:
means for receiving a light signal from an access point communicating information to the UE, said light signal including at least some data from a gateway device which supplied said data to the access point via a power line communications link; and
means for communicating feedback information from said UE device to the gateway device via a communications channel which includes a wireless uplink, said feedback information communicating visible light communications (VLC) channel quality information and including a suggested modulation constellation size or suggested coding rate to be used by the access point during future VLC transmissions, said feedback information based at least in part on measurements made by the UE of the received light signal.
10. The UE device of claim 9 , wherein the channel quality information provides information on the quality of a light channel used to communicate said light signal from the access point to the UE device.
11. The UE device of claim 9 , further comprising:
means for performing a signal to noise ratio (SNR) estimate for a VLC modulation carrier based on a received pilot signal included in said light signal.
12. The UE device of claim 11 , wherein feedback information includes SNR information on a per light channel modulation carrier basis for each of a plurality of light channel modulation carriers used to communicate said light signal.
13. The UE of claim 9 , wherein the measurements made by the UE of the received light signal are for a previous communication between the access point and the UE.
14. The UE of claim 9 , wherein the feedback information further comprises power line channel quality information.
15. The UE of claim 9 , wherein the measurements are based on VLC pilot signals or traffic data signals received by the UE.
16. The UE of claim 9 , wherein the wireless uplink comprises wireless radio signaling or wireless infrared signaling.
17. A computer program product for use in a user equipment (UE) device, the computer program product comprising:
a non-transitory computer readable medium comprising:
code for causing at least one computer to receive a light signal from an access point communicating information to the UE, said light signal including at least some data from a gateway device which supplied said data to the access point via a power line communications link; and
code for causing said at least one computer to communicate feedback information from said UE device to the gateway device via a communications channel which includes a wireless uplink, said feedback information communicating visible light communications (VLC) channel quality information and including a suggested modulation constellation size or suggested coding rate to be used by the access point during future VLC transmissions, said feedback information based at least in part on measurements made by the UE of the received light signal.
18. The computer program product of claim 17 , wherein the measurements made by the UE of the received light signal are for a previous communication between the access point and the UE.
19. The computer program product of claim 17 , wherein the feedback information further comprises power line channel quality information.
20. The computer program product of claim 17 , wherein the measurements are based on VLC pilot signals or traffic data signals received by the UE.
21. The computer program product of claim 17 , wherein the wireless uplink comprises wireless radio signaling or wireless infrared signaling.
22. A user equipment (UE) device comprising:
at least one processor configured to:
receive a light signal from an access point communicating information to the UE, said light signal including at least some data from a gateway device which supplied said data to the access point via a power line communications link; and
communicate feedback information from said UE device to the gateway device via a communications channel which includes a wireless uplink, said feedback information communicating visible light communications (VLC) channel quality information and including a suggested modulation constellation size or suggested coding rate to be used by the access point during future VLC transmissions, said feedback information based at least in part on measurements made by the UE of the received light signal; and
memory coupled to said at least one processor.
23. The UE device of claim 22 , wherein the channel quality information provides information on the quality of a light channel used to communicate said light signal from the access point to the UE device.
24. The UE device of claim 22 , wherein said at least one processor is further configured to perform a signal to noise ratio (SNR) estimate for a VLC modulation carrier based on a received pilot signal included in said light signal.
25. The UE device of claim 24 , wherein feedback information includes SNR information on a per light channel modulation carrier basis for each of a plurality of light channel modulation carriers used to communicate said light signal.
26. The UE of claim 22 , wherein the measurements made by the UE of the received light signal are for a previous communication between the access point and the UE.
27. The UE of claim 22 , wherein the feedback information further comprises power line channel quality information.
28. The UE of claim 22 , wherein the measurements are based on VLC pilot signals or traffic data signals received by the UE.
29. The UE of claim 22 , wherein the wireless uplink comprises wireless radio signaling or wireless infrared signaling.