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[–]ConferenceQA 1 point2 points ago* 

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Asker and Affiliation: Chin Zhong from the Nanotechnology Group, University of Singapore

Question: It seems that the RSSI is a very important metric, and commercial RFID readers do not expose this interface. Can you tell us a little bit more about commercial readers and how they measure RSSI?

Answer: Commercial readers do report RSSI for each tag; in each back-scatter message it measures the RSSI. They also report a packet loss number for a set time interval.

Question 2: Does the RSSI include the reflected interference from the wall?

Answer: That is hard to know; commercial readers are probably doing some form of signal processing to help eliminate this, and I do not know if RSSI is measured before or after this filtering. It would be great to know exactly how it is measured, but that information is very proprietary.

Question 3: How can you make sure that coding / channel commands to the reader are received?

Answer: Changing bitrate and coding scheme are included in the EPC Gen 2 protocol. The header in the forward signal contains bits which specify this; we are not changing the protocol.