WISENET
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WIRELESS COMMUNICATION PROJECTS

Wireless sensor nodes are required to be small, versatile, inexpensive, and to have a long life time. The most energy demanding part of a node is the wireless communication.

Communication energy is used both for transmission as well as for the electronics in the node. The electronic parts, which are also active during receiving, is the dominating part. The reason is that transmission distances are so small which the requires relative low energy. This means that the wireless nodes should turn off the electronics ("sleep mode") as much as they possibly to save energy and should not constantly listening on the radio for data. Also, when awake, they should to spend as little energy as possible on sending and receiving information.

To obtain highly efficient nodes we do research into scheduling of wake-ups, multi-hop routing and transmission techniques. On the hardware side, we investigate how antennas fit on a tiny nodes and how to make highly efficient in varying environments.

An important issue for obtaining reliable communications is the radio channel properties. If the channel is static and we know the distances between nodes, then we can easily calculate how much energy we have to invest for transmitting or receiving our data.

A more difficult scenario arises if the radio channel quality is varying with time. This can happen if sensor nodes are operating in, for example, malls or along the side of roads with heavy traffic. In such cases we have to spend more energy to guard against information loss.

We will investigate the radio channel properties for typical wireless sensor network scenarios.