Table 1.

Summary of existing duplicate RFID data filtering approaches.

Existing Approaches	Weaknesses
ESP and RFID Cube	Delayed process because need to wait all readings to be complete before duplicate readings can be filtered.
RRE	Only suitable if the tagged objects are not moving which is rare in RFID application.
Sliding windows	Need to scan along the sliding windows every time new reading coming in which is not efficient because it scans almost the same data.
Landmark windows	The size of the windows can be very big if want to produce more accurate results than sliding windows.
Bloom filter	It does not allow deletion which can make its filter easily becoming ‘full’ and generate a lot of false positive.
TDMA, MRFID	Put readers into different slot to do readings. It is not suitable for application that requires all the reader to be turned on at the same time.
EIFS	Only do duplicate filtering and does not preserved reading to the rightful reader.