Opportunistic networks (please see iClouds), formed by personal user devices, exploit private resources of users, mainly battery power and device memory, thus there arises the question, why should a user take part in the system at all?
An obvious benefit for the user is the potential fulfillment of his information needs. The device collects only information the user is interested in. In return, this information is shared with others.
In addition, the opportunistic network model can be extended with an incentive scheme to stimulate and thus increase user participation. The adPASS incentive scheme allows users to gain some kind of benefit by passing information on to other users. The core idea is presented next.
The incentive scheme rewards users who partly help to carry information from an information producer to an information consumer. Figure 1 illustrates this. A producer (blue node) passes information to nodes (green) in communication range. The information is passed on only if an entry on the iWish list matches the information (see iClouds project for iWish/iHave). In the example, the information is passed on from node to node until it reaches a consumer that uses the information for his benefit (red node). In return, all nodes framed in the yellow box should be rewarded by the producer or the consumer since they helped in bringing them together. The set of nodes framed in the yellow box is called bearer chain.
The incentive scheme distinguishes different roles of opportunistic network participants.
- An information producer is a node that creates information and initiates its dissemination
- An information bearer receives information from a producer or another bearer and passes it on to other bearers or consumers. A bearer is only interested in gaining a reward for transporting information
- An information consumer receives information from a producer or bearer.
He takes some action on it that is beneficial for himself and the producer.
This leads towards dispensing a reward to all bearers that took part in carrying information down the producer-to-consumer path.
A node can act both as, a bearer and a consumer.