Efficient information collection protocols for sensor-augmented RFID networks

Similar to the revolutionary change that the barcode system brought to the retail industry, the RFID technologies are expected to revolutionize the warehouse and inventory management. After RFID tags are deployed to make the attached objects wirelessly identifiable, a natural next step is to invent new ways to benefit from this "infrastructure". For example, sensors may be added to these tags to gather real-time information about the state of the objects or about the environment where these objects reside. This leads to the problem of designing efficient protocols to collect such information from the tags. It is a new problem that the existing work cannot solve well. In this paper, we first show that a straightforward polling solution will not be efficient. We then propose a single-hash information collection protocol that works much better than the polling solution. However, a wide gap still exists between the execution time of this protocol and a lower bound that we establish. Finally, we propose a multi-hash information collection protocol that further reduces the expected execution time to within 1.61 times the lower bound.