Team looks at data quality in ad hoc mobile networks

Such networks allow people such as military or emergency-response teams in multiple, rapidly moving vehicles to communicate with each other.

‘Our goal was to get the highest data rate possible, without compromising the fidelity of the signal,’ said Dr Alexandra Duel-Hallen, a professor of electrical and computer engineering at NC State and co-author of a paper describing the work.

According to a statement, transmitting data within MANETs is challenging because every node that transmits and receives data is in motion — and the faster they are moving, the harder it is for the network to identify effective relay ‘paths’ for transmitting data. This is because the power of the data-transmission channels fluctuates much more rapidly at high speed.

To address this issue, researchers developed a method to improve the ability of each node in the network to select the best path for relaying data, as well as the best for transmitting the data that ensures reliable reception.

When a node needs to transmit a message, it first measures the strength of transmissions it is receiving from potential relays. Those data are then plugged into an algorithm that predicts which relay will be strongest when the message is transmitted.

By predicting the strength of the relay, the algorithm also tells the node the rate at which it should transmit the data. If it tries to send too much data too quickly, the data quality will suffer — the data could be compromised. If the rate of data transmission is too slow, the network won’t be operating at peak efficiency.

A paper, ‘Enabling Adaptive Rate and Relay Selection for 802.11 Mobile Ad Hoc Networks’, will be presented at IEEE’s International Conference on Communications in Ottawa on 10–15 June.