SCATTERNET PROTOCOL

We developed a new scatternet protocol (SNP) layer that
makes the Bluetooth communication transparent. A user who
wants to send data to any other device in a Bluetooth network
simply sends a packet with the address of the receiver
into the network. The SNP is responsible for finding the
shortest path through the network and to guarantee that the
packet is received by the target device. When the network
is changed the SNP is adapting and learning new paths.
Only local information is used to find the shortest path.
The SNP extracts the routing information by looking at
the data packets that are passing the Bluetooth device it
is running on. The SNP also supports broadcasts and gives
full remote control for all connected Bluetooth devices. This
allows a user to control all Bluetooth devices in a scatternet
from a single host device. To support these functionalities
we added three new mechanisms to the original Bluetooth
stack: (1) SNP addresses are new user defined addresses. (2)
SNP packets are responsible to carry the payload through
the scatternet. (3) SNP friend tables contain local routing
information that is used to forward the SNP packets towards
the receiver.

Fig. 1. SNP packets. The header contains 5 Bytes specifying the command,
the SNP addresses of the receiver and sender, the number of hops a packet
was traveling as well as 1 Byte giving the amount of payload that the packet
contains.