A QoS Evaluation Testbed for Mac Protocols for Wireless Camera Networks

Existing QoS metrics can only be used for wireless sensor networks when the capability of sensor nodes is limited to making simple measurements such as temperature, pressure, etc. These metrics do not capture the communication patterns encountered when sensing is more elaborate, as in wireless camera networks where the need for distributed computation of image data may result in highly bursty communications among the nodes in a cluster. Whether or not a wireless camera network can successfully engage in, say, an object tracking task depends on whether the MAC protocol allows for these communication patterns to succeed with high reliability. Our testbed characterizes a MAC protocol on the basis of the following three criteria: time-bounded parameter-estimation accuracy (TIBPEA), latency, and energy efficiency. (An example of TIBPEA would be the precision with which an object can be located in space in a time-bounded manner by a cluster of nodes in the presence of bursty communications entailed by collaborative computing.) Our testbed simulator models bursty communications by enhanced data broadcast rates as needed by a vision task. Our paper includes characterization of a well-known MAC protocol.