| Summary: | Wireless sensor networks (WSN) have generated tremendous interest among
researchers these years because of their potential usage in a wide variety of applications.<p>
Sensor nodes are inexpensive portable devices with limited processing power and energy
resources. Sensor nodes can be used to collect information from the environment, locally
process this data and transmit the sensed data back to the user.<p>
This thesis proposes a new reliable data delivery protocol for general point-to-point
data delivery (unicasting) in wireless sensor networks. The new protocol is designed that
aims at providing 100% reliability when possible as well as minimizing overhead and
network delay. The design of the new protocol includes three components. The new
protocol adopts a NACK-based hop-by-hop loss detection and recovery scheme using
end-to-end sequence numbers. In order to solve the single/last packet problem in the
NACK-based approach, a hybrid ACK/NACK scheme is proposed where an ACK-based approach is used as a supplement to the NACK-based approach to solve the single/last packet problem. The proposed protocol also has a new queue management scheme that gives priority to new data. By introducing the idea of a Ready_Bit and newer packet first
rule in the transmission queue, nodes can detect and recover lost packets in parallel with
the normal data transmission process.
The performance of the new protocol is tested in a Crossbow MicaZ testbed.
Experimental results show that the new protocol performs well under various system and
protocol parameter settings.
|
|---|
