A network system having two layers is proposed. This system uses radio as a transmission medium to the lower layer and a conventional LAN to the upper one. The users of a wireless network enjoy complete freedom from frequent reconfiguration of existing terminal arrangements. However, office buildings present a harsh environment for radio transmission because of numerous reflections from walls, furniture, and even people. A dynamic channel assignment scheme with no host computers is also described. The system performance is analyzed through computer simulations. The results show that 100 remote terminals are accommodated to 25 base stations safely on the conditions that the upper layer is a 10-Mb/s carrier sense multiple access with collision detection (CSMA/CD) network and the lower is a 32-kb/s CSMA packet radio network.