CarpetLAN is a novel indoor wireless(-like) broad-band networking and positioning system. It uses the floor surface and the human body as an Ethernet-cable, and weak electric fields as the transmission media. Portable and wearable devices can connect to the network while the user stands or walks on the floor; connection speed is 10Mbps. Home and office appliances can also access the network if they are just put on the floor. CarpetLAN also provides an indoor positioning function, which is urgently needed for realizing “ubiquitous” communication. This electric field based transmission system yields ultra-micro communication cells, so the positions of humans and appliances can be detected with about 1 meter accuracy.