Quick Convergecast in ZigBee/IEEE 802.15.4 Tree-Based Wireless Sensor Networks
Goal:
To design protocols to achieve low-latency convergecast in ZigBee tree-based wireless sensor networks
Challenge:
How to find a better beacon schedule
An Efficient Flow Control and Medium Access in Multihop Ad Hoc Networks with Multi-Channels
We propose a new multichannel MAC protocol using multichannel transmission,
and develop a hop-by-hop congestion control scheme, which is named ˇ§Efficient
Flow Control with Multi-channelsˇ¨ (EFCM). The EFCM scheme modifies the IEEE 802.11
RTS/CTS frame format to reserve bandwidth in different channels. It also solves the
hidden terminal problem in the multichannel environment. The intermediate nodes have
a higher priority than the source (or leaf) nodes to contend for the right of
transmission to solve the intraflow contention. In order to solve the interflow
contention, congestion control is taken in every node to construct a flow table,
which restricts the number of packets of every flow passing by congested nodes.
According to the simulation results, the whole network throughputs of EFCM are
improved significantly.
Main achievements and outcomes
Research or technology outcomes
The congestion problem especially in multi-hop MANETs is not
discussed in the previous works. We also solve the hidden terminal problem in
our proposed protocol. Using our protocol can increase network throughput and
decrease end-to-end delay. The protocol is published in VTC 2007-Fall
A Link-layer Protocol for Event-driven WSNs
Joint two issues
Exploiting the spatial correlation of sensor data
Designing a specific MAC protocol
RGP: Active Route Guiding Protocol for Wireless Sensor Networks with Obstacles
We propose novel algorithms that enable the existing location-based routing
protocols resisting obstacles. The proposed protocols actively establish a forbidden
region for concave obstacles and make the obstacle information transparent. Packets
will be guided to overcome the obstacle and move along the shortest path from sensor
nodes to the sink node.
Main achievements and outcomes
Research or technology outcomes
As far as we know, this is the first work that considers multiple
obstacles and guides the packet to move along the shortest path with low control
overheads. This paper was published by the IEEE MASS 2006.
Efficient Broadcasting Protocols for Regular Wireless Sensor Networks
Broadcast is a fundamental operation for all kinds of networks and it has
not been addressed seriously in the WSN. We propose two types of power and time
efficient broadcasting protocols, namely one-to-all and all-to-all broadcasting
protocols, for five different WSN topologies. Our broadcasting protocols conserve
power and time by choosing as few relay nodes as possible to scatter packets to
the whole network. Besides, collisions are carefully handled such that our
broadcasting protocols can achieve 100% reachability.
Main achievements and outcomes
Research or technology outcomes
This is a pioneer work for broadcasting protocols on regular WSNs.
This work was published in Journal of Wireless Communications & Mobile Computing.
