US retail giant Target gave a huge boost to Internet of Things (IoT) lighting recently when it decided to install lighting-based indoor navigation systems in nearly 1000 stores by Christmas. But in so doing, it has created a bit of a mystery about the technology that it has chosen.

　　Interested in articles & announcements on smart lighting in conjunction with communications technology such as VLC?

　　As LEDs Magazine reported earlier this month, Target will tap LED ceiling lights from Acuity Brands to send signals to shoppers' phones. A Target app will then turn those signals into maps that help guide people around the aisles to specific items, and to provide information about products and discounts.

　　The question is, how is Target emitting the signals that emerge from the lighting fixtures?

　　Many lighting, communications, and IT engineers are interested in the answer because a general technology battle is emerging between various radio technologies. The RF techniques are also vying against a lighting-specific method called visible light communication (VLC), which uses LED lightwaves — rather than radio frequencies — to carry data. To add to the drama, indoor positioning systems don't even have to reside in the lights, although lighting firms are pushing to put them there.