INT has developed a product line for building large manageable wireless networks for monitoring and control. ZigBee-over-powerline Bridge allows to connect two or more wireless ZigBee sub-networks to in-home power line infrastructure.

MAIN FUNCTION:

The bridge looks like a normal full-functionality device with routing capabilities from the point of view of the rest of the ZigBee network. If there is no coordinator present, it assumes the role of the coordinator. At the same time, the bridge is capable of forwarding some of the NWK layer packets over a powerline to other ZigBee-over-powerline Bridge. The destination bridge receives the packet from the powerline and forwards it further, normally across a radio link. Several powerline hops can take place if the distance traversed across the powerline is too long for one-hop transmission. The HomePlug v.1.0 standard is used for transmitting data over powerline. It is implemented by the Intellon INT5200 chip, which allows for data transfer rates of up to 14 Mbps. This is sufficient for carrying multiple simultaneous ZigBee data exchanges because their maximum data transfer rate is only 250 Kbps.

ENCAPSULATION USED FOR CARRYING ZIGBEE DATA:

The NWK packets are encapsulated into UDP (over IPv4) packets before being sent over the powerline. The reason for this is to increase the flexibility of use: an IP packet can be forwarded across any other network including the Internet. A third party HomePlug to Ethernet adapter can be used for this purpose.

AUTO-CONFIGURATION AND NEIGHBOR DISCOVERY:

A bridge must be assigned an IP address in order to be able to send and receive IP packets as described above. The designers have strived to achieve a balance between simplicity and flexibility of IP address configuration, so the resulting algorithm is as follows. Upon the start-up, the bridge broadcasts DHCP requests. If there are replies, it uses the reply with the highest priority to obtain its IP address, the net mask, the default gateway, and the DNS server. If no reply was received before the configured timeout expires, the auto-IP procedure is used.

PHYSICAL AND RADIO-ELECTRICAL CHARACTERISTICS:

The bridge is mains powered. Its housing is designed for hanging from the socket into which it is plugged, so no DIN-rail or shelf is needed for mounting the bridge. Such mounting is safe due to the relatively small dimensions and weight of the device. An optional external antenna can be used to increase the transmission range and the link quality.

ZIGBEE-OVER-POWERLINE BRIDGE CHARACTERISTICS: