Ways of Benchmarking the UHF RFID Systems Damon Tsang 第一屆中國無線射頻識別基準測試發展論壇 暨 備忘協議簽訂儀式 March 1, 2008

A Typical UHF RFID System Main components contain: Reader Antennas Tags Computer software for controlling the reader to read from and write to tags IC Tag Antenna Tag External Interface Antenna Computer Software Reader 2018/12/27 CSL--A Chung Nam Company

Common Problems found in UHF RFID Systems Missing Tags - Out of read coverage - Insufficient output power Cross Reads - Reflection - Over power 2018/12/27 CSL--A Chung Nam Company

Scenario 1 – Read/Write Tags in An Assembly Line Antenna Read coverage 50 trials – Fail to read all tags Rec EPC ID RSSI 1 00000000000EA00000000001 -47 17 00000000000EA00000000017 -48 18 Missing 19 20 Tags 3 tags gone missing Outcomes: Shorter the antenna, narrower the reading range Only 17 tags are read due to out of range Conditions: Be able to read all 20 tags at the height of 0.75m Read with 1 antenna Output power at 28dBm Cont… 2018/12/27 CSL--A Chung Nam Company

Scenario 2 – Read/Write Tags in An Assembly Line 50 trials – Fail to read all tags Antenna Read coverage Wider read range Rec EPC ID RSSI 1 00000000000EA00000000001 -47 16 00000000000EA00000000016 -45 17 00000000000EA00000000017 -48 18 00000000000EA00000000018 -38  19 Missing 20 -58  Tags Conditions: Increase the height to 1m to cover wide read range Be able to read all 20 tags Read with 1 antenna Output power at 28dBm Outcomes: Higher the antenna, wider the reading coverage Be able to read more tags Only 19 tags are read due to the insufficient power Cont… 2018/12/27 CSL--A Chung Nam Company

Scenario 3 – Read/Write Tags in An Assembly Line 50 trials – Cross read occurs Output Power 28dBm -> 30dBm Rec EPC ID RSSI 1 00000000000EA00000000001 -55    19 00000000000EA00000000019 -47    20 00000000000EA00000000088 -50    21 -65    22 00000000000EA00000000098 -68    Conditions: Increase the height to 1m to cover wider read range Increase the output power to 30dBm Be able to read all 20 tags Read with 1 antenna Avoid cross reading of tags Outcomes: Higher the antenna, wider the reading coverage More output power to radiate the tags Be able to read all tags 2 more unwanted tags are read due to an increase of output power (cross read occurs) Cont… 2018/12/27 CSL--A Chung Nam Company

Scenario 4 – Read/Write Tags in An Assembly Line Set RSSI to -60 dBm 19 00000000000EA00000000019 -47    20 00000000000EA00000000088 -50    21 -65    22 00000000000EA00000000098 -68    50 trials – Perfect result! EPC ID RSSI 1 00000000000EA00000000001 -53   19 00000000000EA00000000019 -48   20 00000000000EA00000000020 -50    Solutions: Power increases from 28dBm to 30dBm Change the value of the RSSI Filter the unwanted tags < -60dBm 2018/12/27 CSL--A Chung Nam Company

Scenario 5 – Double Gate Door Benchmarking Forklift trucks are in queue waiting Database Checklist Rec EPC ID RSSI 1 00000000000EA00000000001 -38 2 00000000000EA00000000002 -47 Association 38 00000000000EA00000000038 -45 39 00000000000EA00000000039 -47 40 00000000000EA00000000040 -52 Out Conditions: Be able to read all 40 tags 4 antennas with output power at 32.5dBm each Outcomes: 40 tags are successful read against the backend database Cont… 2018/12/27 CSL--A Chung Nam Company

Scenario 6 – Double Gate Door Benchmarking Database Checklist Forklift trucks are in queue waiting Rec EPC ID RSSI 1 00000000000EA00000000001 -38 2 00000000000EA00000000002 -47 38 Missing 39 00000000000EA00000000039 -48  40 00000000000EA00000000040 -52 Association Go back & proceed again due to missing tags Outcomes: 1 tag is missing after checking against the backend database Conditions: Be able to read all 40 tags 4 antennas with output power at 32.5dBm each Solutions: Go back and pass the gate door again until all tags are read Cont… 2018/12/27 CSL--A Chung Nam Company

Scenario 7 – Double Gate Door Benchmarking Forklift trucks are in queue waiting Database Checklist Association 38 00000000000EA00000000038 -68 39 00000000000EA00000000039 Missing 40 00000000000EA00000000040 -52   Database Checklist Association Rec EPC ID RSSI 1 00000000000EA00000000001 -38 39 00000000000EA00000000039 -38 40 00000000000EA00000000040 -52 Conditions: Be able to read all 40 tags when passing thru 2 doors 8 antennas with output power at 32.5dBm each Outcomes: 1 tag is missing at the Door 1 100% read is at the Door 2 Improve the chance of success of the reading rate Shorten the queuing time Cont… 2018/12/27 CSL--A Chung Nam Company

Scenario 8 – Double Gate Door Benchmarking Forklift trucks are in a queue waiting Database Checklist 38 00000000000EA00000000038 Missing 39 00000000000EA00000000039 -35    40 00000000000EA00000000040 -52    Cross referencing Database Checklist 38 00000000000EA00000000038 -48    39 00000000000EA00000000039 -38    40 00000000000EA00000000040 Missing Outcomes: No identical missing tags read in 2 doors assuming that 100% read rate is achieved – no missing tags occur Improve the chance of success of the reading rate Shorten the queuing time Conditions: Be able to read all 40 tags when passing thru 2 doors 8 antennas with output power at 32.5dBm each Cont… 2018/12/27 CSL--A Chung Nam Company

CSL--A Chung Nam Company Summary Benchmarking a RFID system in an assembly line is based on the read coverage, output power, and RSSI to minimize missing tags and cross reads Benchmarking a RFID system using the double gate door system avoids missing tags, increases productivity, and reduces queuing time 2018/12/27 CSL--A Chung Nam Company

CSL--A Chung Nam Company Thank You!! Contact: damontsang@convergence.com.hk 2018/12/27 CSL--A Chung Nam Company