SlideShare ist ein Scribd-Unternehmen logo
1 von 11
Downloaden Sie, um offline zu lesen
TECO
Protocol Optimizations
using anonymous EPC
   Gen2 Inventories
Local Inventory Problem



      How many products of a
       certain type are in a
              shelf ?

4-Apr-12        Copyright TecO 2007, Restricted Use   2
Conventional Solution

            10000
                                                                                                          Use high level interfaces
                                                                                    .95
                                                                                    .99                   Get IDs of all/selected
             8000                                                                                          tags

             6000                                                                                      Problem:
                                                                                                        Long readings
time (ms)
      m
      e
      s
      )
      (
      t
      i




                                                                                                        Static environment
             4000



                                                                                                        Still uncertainty
             2000




                0
                                                                                                       Solution:
                    0       10       20        30        40          50      60        70       80
                                                    number of tags                                      Statistical approach
                    Source: Vogt, H. (2002). Efficient Object Identification with Passive RFID Tags.

               4-Apr-12                                               Copyright TecO 2007, Restricted Use                        3
Problem: Channel Arbitration
                                                                        S ing le Tag Repl y
                                                                                                                                          QueryRep or
           Interrogato r    Select    CW      Query              CW                 Ack              CW                  QueryRep         QueryAdjust
                                                                                                                                          if EPC is valid

                                                                                                                                          NAK if EPC
                                                                                                                           NAK
                                                                                                                                          is invalid


           Ta g                                                 RN16                           PC + EPC+ CRC16

                                      T4                   T1           T2                T1                     T2




                              C ollided R eply                  No Repl y                           Invalid AC K

           Inte rrogato r   Query           CW             QueryR           CW      QueryRep        CW             Ack            CW       QueryRep

                                          Collision                         No                                                    No
                                          Detected                          Reply                                                 Reply
           Ta g                             RN16                                                   RN16


                                     T1               T2               T1    T3                                              T1     T3




4-Apr-12                                         Copyright TecO 2007, Restricted Use                                                                        4
Idea 1: No IDs - just count

                                                              S ing le Tag Repl y
                                                                                                                   QueryRep or
           Interrogato r   Select   CW    Query        CW           Ack                CW               QueryRep   QueryAdjust
                                                                                                                   if EPC is valid

                                                                                                          NAK
                                                                                                                   NAK if EPC
                                                                                                                   is invalid


           Ta g                                        RN16                      PC + EPC+ CRC16

                                    T4            T1          T2            T1                     T2




                   50% Speed up
4-Apr-12                                 Copyright TecO 2007, Restricted Use                                                         5
Idea 2: Count Collisions and
                    empty slots
                               C ollided R eply                    N o Re ply

            Inte rrogato r   Query            CW            Query             CW

                                           Collision                          No
                                           Detecte d                          Reply
            Tag                              RN16

                                      T1               T2                T1     T3



   Collision means 2 or more Tags

   calculate: min # of tags

   estimate: # tags
4-Apr-12                     Copyright TecO 2007, Restricted Use                      6
Estimation of # Tags
                in Slotted Aloha Frame

            Lower bound

            Estimation




      Source: Vogt, H. (2002). Efficient Object Identification with Passive RFID Tags.

4-Apr-12                      Copyright TecO 2007, Restricted Use                        7
Algorithm

  (1) Select Product (prefix in EPC memory)

  (2) Start a new Round of 2Q slots

  (3) Count Success, Empty and Collisions

  (4) Calculate estimated and minimal
  number of Tags


4-Apr-12       Copyright TecO 2007, Restricted Use   8
Fully EPC Gen2 compatible
              Query                                           Power-up & ~killed
                              Slot                                                                                    NEW ROUND
             QueryRep                          slot                                                          CMD: Query [mismatched
            QueryAdjust      Counter
                                                                                                                   inventoried or SL flags]
                                                                                                             Reply: None
            CMD: Select
             Action: Return to ready
                                                                   Ready
             Reply: None. Note 1
            CMD: Query                                                                                                NEW ROUND
             Action: New round                                                                               CMD: Query [slot > 0 & matching
             Reply: Note 3                                                                                         (inventoried & SL) flags]
            CMD: All other                                                                                   Reply: None
             Action: Remain in ready
             Reply: None
                                                                                           CMD: QueryRep, QueryAdjust [slot <> 0]
                                                                  Arbitrate                Reply: None

                                                                                                                      NEW ROUND
                                              CMD: QueryAdjust, QueryRep [slot=0]                            CMD: Query [slot = 0 & matching
                                              Reply: New RN16                                                      (inventoried & SL) flags]
            CMD: Select                                                                                      Reply: New RN16
             Action: Return to ready
             Reply: None. Note 1
            CMD: Query
             Action: New round                                                             CMD: QueryAdjust [slot = 0]
                                                                    Reply                  Reply: New RN16
             Reply: Note 3
            CMD: All other
             Action: Return to arbitrate
             Reply: None.                     CMD: ACK [valid RN16]                    CMD: ACK [valid RN16]
            CMD: None within time T2          Reply: PC, EPC, CRC-16                   Reply: PC, EPC, CRC-16
             Action: Return to arbitrate                                               CMD: Req_RN [invalid RN16]
             Reply: None.                                                              Reply: None

                                                              Acknowledged
                                                                                             CMD: Req_RN [valid RN16] & {access password = 0}
                                                                                             Reply: Handle
                                           CMD: Req_RN [valid RN16] &
                                                {access password <> 0}                     CMD: ACK [valid han   dle]
                                           Reply: handle                                   Reply: PC, EPC, CRC-1     6
                                                                                           CMD: Req_RN, Read, Write, Lock, BlockWrite, BlockErase
                                                                                           Reply: See state-transition tables
            CMD: Select                                                                    CMD: Kill [valid handle & kill password = 0]
             Action: Return to ready                                Open
                                                                                           Reply: Error code
             Reply: None. Note 1                                                           CMD: Kill, Access [invalid handle]
            CMD: Query                                                                     Reply: None
             Action: New round
             Reply: Notes 2, 3                                           CMD: Access [valid handle & valid access password]
            CMD: QueryRep, QueryAdjust                                   Reply: handle when done
4-Apr-12     Action: Return to ready           Copyright TecO 2007, Restricted Use                                                                  9
Tag Requirements

     EPC Gen2
     ...




4-Apr-12     Copyright TecO 2007, Restricted Use   10
Reader Requirements
          Stage 1:
             Get # of collisions
             Get # of slots / frames
             Select product group*
          Stage 2:
             Set # of slots/frames
          Stage 3:
             Raw Reader/No Firmware
             Change Algorithm (i.e. No ACKs)


        * product distribution could also be estimated
4-Apr-12                        Copyright TecO 2007, Restricted Use   11

Weitere ähnliche Inhalte

Mehr von Till Riedel

From Load Forecasting to Demand Response - A Web of Things Use Case
From Load Forecasting to Demand Response  - A Web of Things Use CaseFrom Load Forecasting to Demand Response  - A Web of Things Use Case
From Load Forecasting to Demand Response - A Web of Things Use CaseTill Riedel
 
IoT 2014 Value Creation Workshop: SDIL
IoT 2014 Value Creation Workshop: SDILIoT 2014 Value Creation Workshop: SDIL
IoT 2014 Value Creation Workshop: SDILTill Riedel
 
A device-free future of ubicomp?
A device-free future of ubicomp?A device-free future of ubicomp?
A device-free future of ubicomp?Till Riedel
 
Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...
Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...
Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...Till Riedel
 
Relate: Architecture, Systems and Tools for Relative Positioning
Relate: Architecture, Systems and Tools for Relative PositioningRelate: Architecture, Systems and Tools for Relative Positioning
Relate: Architecture, Systems and Tools for Relative PositioningTill Riedel
 
Pluggable Realworld Interfaces
Pluggable Realworld InterfacesPluggable Realworld Interfaces
Pluggable Realworld InterfacesTill Riedel
 
A Community Platform for Auto-Annotated Recreational Maps
A Community Platform for Auto-Annotated Recreational MapsA Community Platform for Auto-Annotated Recreational Maps
A Community Platform for Auto-Annotated Recreational MapsTill Riedel
 
Ubiquitous Resources Abstraction using a File System Interface on Sensor Nodes
Ubiquitous Resources Abstraction using a File System Interface on Sensor NodesUbiquitous Resources Abstraction using a File System Interface on Sensor Nodes
Ubiquitous Resources Abstraction using a File System Interface on Sensor NodesTill Riedel
 
Architecture for Collaborative Business Items
Architecture for Collaborative Business ItemsArchitecture for Collaborative Business Items
Architecture for Collaborative Business ItemsTill Riedel
 
Implicit Middleware
Implicit MiddlewareImplicit Middleware
Implicit MiddlewareTill Riedel
 
Barcodes, RFID or Smart Items? Evaluating track and trace technology today a...
Barcodes, RFID or Smart Items? Evaluating track and trace technology  today a...Barcodes, RFID or Smart Items? Evaluating track and trace technology  today a...
Barcodes, RFID or Smart Items? Evaluating track and trace technology today a...Till Riedel
 
uBox A Distributed Resource Management Architecture for the Web-of-Things
uBox A Distributed Resource Management Architecture for the Web-of-ThingsuBox A Distributed Resource Management Architecture for the Web-of-Things
uBox A Distributed Resource Management Architecture for the Web-of-ThingsTill Riedel
 
Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...
Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...
Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...Till Riedel
 

Mehr von Till Riedel (15)

From Load Forecasting to Demand Response - A Web of Things Use Case
From Load Forecasting to Demand Response  - A Web of Things Use CaseFrom Load Forecasting to Demand Response  - A Web of Things Use Case
From Load Forecasting to Demand Response - A Web of Things Use Case
 
IoT 2014 Value Creation Workshop: SDIL
IoT 2014 Value Creation Workshop: SDILIoT 2014 Value Creation Workshop: SDIL
IoT 2014 Value Creation Workshop: SDIL
 
A device-free future of ubicomp?
A device-free future of ubicomp?A device-free future of ubicomp?
A device-free future of ubicomp?
 
Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...
Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...
Thesis presentation: Middleware for Ubicomp - A Model Driven Development Appr...
 
Relate: Architecture, Systems and Tools for Relative Positioning
Relate: Architecture, Systems and Tools for Relative PositioningRelate: Architecture, Systems and Tools for Relative Positioning
Relate: Architecture, Systems and Tools for Relative Positioning
 
ParticleVM
ParticleVMParticleVM
ParticleVM
 
Pluggable Realworld Interfaces
Pluggable Realworld InterfacesPluggable Realworld Interfaces
Pluggable Realworld Interfaces
 
A Community Platform for Auto-Annotated Recreational Maps
A Community Platform for Auto-Annotated Recreational MapsA Community Platform for Auto-Annotated Recreational Maps
A Community Platform for Auto-Annotated Recreational Maps
 
Ubiquitous Resources Abstraction using a File System Interface on Sensor Nodes
Ubiquitous Resources Abstraction using a File System Interface on Sensor NodesUbiquitous Resources Abstraction using a File System Interface on Sensor Nodes
Ubiquitous Resources Abstraction using a File System Interface on Sensor Nodes
 
Architecture for Collaborative Business Items
Architecture for Collaborative Business ItemsArchitecture for Collaborative Business Items
Architecture for Collaborative Business Items
 
Implicit Middleware
Implicit MiddlewareImplicit Middleware
Implicit Middleware
 
Syncob
SyncobSyncob
Syncob
 
Barcodes, RFID or Smart Items? Evaluating track and trace technology today a...
Barcodes, RFID or Smart Items? Evaluating track and trace technology  today a...Barcodes, RFID or Smart Items? Evaluating track and trace technology  today a...
Barcodes, RFID or Smart Items? Evaluating track and trace technology today a...
 
uBox A Distributed Resource Management Architecture for the Web-of-Things
uBox A Distributed Resource Management Architecture for the Web-of-ThingsuBox A Distributed Resource Management Architecture for the Web-of-Things
uBox A Distributed Resource Management Architecture for the Web-of-Things
 
Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...
Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...
Using Web Service Gateways and Code Generation for Sustainable IoT System Dev...
 

Kürzlich hochgeladen

KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostKubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostMatt Ray
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPathCommunity
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopBachir Benyammi
 
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Will Schroeder
 
Introduction to Quantum Computing
Introduction to Quantum ComputingIntroduction to Quantum Computing
Introduction to Quantum ComputingGDSC PJATK
 
Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)Commit University
 
PicPay - GenAI Finance Assistant - ChatGPT for Customer Service
PicPay - GenAI Finance Assistant - ChatGPT for Customer ServicePicPay - GenAI Finance Assistant - ChatGPT for Customer Service
PicPay - GenAI Finance Assistant - ChatGPT for Customer ServiceRenan Moreira de Oliveira
 
Comparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioComparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioChristian Posta
 
Videogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfVideogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfinfogdgmi
 
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyesHow to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyesThousandEyes
 
OpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureOpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureEric D. Schabell
 
AI Fame Rush Review – Virtual Influencer Creation In Just Minutes
AI Fame Rush Review – Virtual Influencer Creation In Just MinutesAI Fame Rush Review – Virtual Influencer Creation In Just Minutes
AI Fame Rush Review – Virtual Influencer Creation In Just MinutesMd Hossain Ali
 
9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding TeamAdam Moalla
 
Designing A Time bound resource download URL
Designing A Time bound resource download URLDesigning A Time bound resource download URL
Designing A Time bound resource download URLRuncy Oommen
 
Digital magic. A small project for controlling smart light bulbs.
Digital magic. A small project for controlling smart light bulbs.Digital magic. A small project for controlling smart light bulbs.
Digital magic. A small project for controlling smart light bulbs.francesco barbera
 
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...Aggregage
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6DianaGray10
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsSeth Reyes
 
Machine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdfMachine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdfAijun Zhang
 
Linked Data in Production: Moving Beyond Ontologies
Linked Data in Production: Moving Beyond OntologiesLinked Data in Production: Moving Beyond Ontologies
Linked Data in Production: Moving Beyond OntologiesDavid Newbury
 

Kürzlich hochgeladen (20)

KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCostKubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
KubeConEU24-Monitoring Kubernetes and Cloud Spend with OpenCost
 
UiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation DevelopersUiPath Community: AI for UiPath Automation Developers
UiPath Community: AI for UiPath Automation Developers
 
NIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 WorkshopNIST Cybersecurity Framework (CSF) 2.0 Workshop
NIST Cybersecurity Framework (CSF) 2.0 Workshop
 
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
Apres-Cyber - The Data Dilemma: Bridging Offensive Operations and Machine Lea...
 
Introduction to Quantum Computing
Introduction to Quantum ComputingIntroduction to Quantum Computing
Introduction to Quantum Computing
 
Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)Crea il tuo assistente AI con lo Stregatto (open source python framework)
Crea il tuo assistente AI con lo Stregatto (open source python framework)
 
PicPay - GenAI Finance Assistant - ChatGPT for Customer Service
PicPay - GenAI Finance Assistant - ChatGPT for Customer ServicePicPay - GenAI Finance Assistant - ChatGPT for Customer Service
PicPay - GenAI Finance Assistant - ChatGPT for Customer Service
 
Comparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and IstioComparing Sidecar-less Service Mesh from Cilium and Istio
Comparing Sidecar-less Service Mesh from Cilium and Istio
 
Videogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdfVideogame localization & technology_ how to enhance the power of translation.pdf
Videogame localization & technology_ how to enhance the power of translation.pdf
 
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyesHow to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
How to Effectively Monitor SD-WAN and SASE Environments with ThousandEyes
 
OpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability AdventureOpenShift Commons Paris - Choose Your Own Observability Adventure
OpenShift Commons Paris - Choose Your Own Observability Adventure
 
AI Fame Rush Review – Virtual Influencer Creation In Just Minutes
AI Fame Rush Review – Virtual Influencer Creation In Just MinutesAI Fame Rush Review – Virtual Influencer Creation In Just Minutes
AI Fame Rush Review – Virtual Influencer Creation In Just Minutes
 
9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team9 Steps For Building Winning Founding Team
9 Steps For Building Winning Founding Team
 
Designing A Time bound resource download URL
Designing A Time bound resource download URLDesigning A Time bound resource download URL
Designing A Time bound resource download URL
 
Digital magic. A small project for controlling smart light bulbs.
Digital magic. A small project for controlling smart light bulbs.Digital magic. A small project for controlling smart light bulbs.
Digital magic. A small project for controlling smart light bulbs.
 
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
The Data Metaverse: Unpacking the Roles, Use Cases, and Tech Trends in Data a...
 
UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6UiPath Studio Web workshop series - Day 6
UiPath Studio Web workshop series - Day 6
 
Computer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and HazardsComputer 10: Lesson 10 - Online Crimes and Hazards
Computer 10: Lesson 10 - Online Crimes and Hazards
 
Machine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdfMachine Learning Model Validation (Aijun Zhang 2024).pdf
Machine Learning Model Validation (Aijun Zhang 2024).pdf
 
Linked Data in Production: Moving Beyond Ontologies
Linked Data in Production: Moving Beyond OntologiesLinked Data in Production: Moving Beyond Ontologies
Linked Data in Production: Moving Beyond Ontologies
 

Protocol Optimizations using anonymous EPC Gen2 Inventories

  • 2. Local Inventory Problem How many products of a certain type are in a shelf ? 4-Apr-12 Copyright TecO 2007, Restricted Use 2
  • 3. Conventional Solution 10000  Use high level interfaces .95 .99  Get IDs of all/selected 8000 tags 6000 Problem:  Long readings time (ms) m e s ) ( t i  Static environment 4000  Still uncertainty 2000 0 Solution: 0 10 20 30 40 50 60 70 80 number of tags  Statistical approach Source: Vogt, H. (2002). Efficient Object Identification with Passive RFID Tags. 4-Apr-12 Copyright TecO 2007, Restricted Use 3
  • 4. Problem: Channel Arbitration S ing le Tag Repl y QueryRep or Interrogato r Select CW Query CW Ack CW QueryRep QueryAdjust if EPC is valid NAK if EPC NAK is invalid Ta g RN16 PC + EPC+ CRC16 T4 T1 T2 T1 T2 C ollided R eply No Repl y Invalid AC K Inte rrogato r Query CW QueryR CW QueryRep CW Ack CW QueryRep Collision No No Detected Reply Reply Ta g RN16 RN16 T1 T2 T1 T3 T1 T3 4-Apr-12 Copyright TecO 2007, Restricted Use 4
  • 5. Idea 1: No IDs - just count S ing le Tag Repl y QueryRep or Interrogato r Select CW Query CW Ack CW QueryRep QueryAdjust if EPC is valid NAK NAK if EPC is invalid Ta g RN16 PC + EPC+ CRC16 T4 T1 T2 T1 T2 50% Speed up 4-Apr-12 Copyright TecO 2007, Restricted Use 5
  • 6. Idea 2: Count Collisions and empty slots C ollided R eply N o Re ply Inte rrogato r Query CW Query CW Collision No Detecte d Reply Tag RN16 T1 T2 T1 T3 Collision means 2 or more Tags calculate: min # of tags estimate: # tags 4-Apr-12 Copyright TecO 2007, Restricted Use 6
  • 7. Estimation of # Tags in Slotted Aloha Frame Lower bound Estimation Source: Vogt, H. (2002). Efficient Object Identification with Passive RFID Tags. 4-Apr-12 Copyright TecO 2007, Restricted Use 7
  • 8. Algorithm (1) Select Product (prefix in EPC memory) (2) Start a new Round of 2Q slots (3) Count Success, Empty and Collisions (4) Calculate estimated and minimal number of Tags 4-Apr-12 Copyright TecO 2007, Restricted Use 8
  • 9. Fully EPC Gen2 compatible Query Power-up & ~killed Slot NEW ROUND QueryRep slot CMD: Query [mismatched QueryAdjust Counter inventoried or SL flags] Reply: None CMD: Select Action: Return to ready Ready Reply: None. Note 1 CMD: Query NEW ROUND Action: New round CMD: Query [slot > 0 & matching Reply: Note 3 (inventoried & SL) flags] CMD: All other Reply: None Action: Remain in ready Reply: None CMD: QueryRep, QueryAdjust [slot <> 0] Arbitrate Reply: None NEW ROUND CMD: QueryAdjust, QueryRep [slot=0] CMD: Query [slot = 0 & matching Reply: New RN16 (inventoried & SL) flags] CMD: Select Reply: New RN16 Action: Return to ready Reply: None. Note 1 CMD: Query Action: New round CMD: QueryAdjust [slot = 0] Reply Reply: New RN16 Reply: Note 3 CMD: All other Action: Return to arbitrate Reply: None. CMD: ACK [valid RN16] CMD: ACK [valid RN16] CMD: None within time T2 Reply: PC, EPC, CRC-16 Reply: PC, EPC, CRC-16 Action: Return to arbitrate CMD: Req_RN [invalid RN16] Reply: None. Reply: None Acknowledged CMD: Req_RN [valid RN16] & {access password = 0} Reply: Handle CMD: Req_RN [valid RN16] & {access password <> 0} CMD: ACK [valid han dle] Reply: handle Reply: PC, EPC, CRC-1 6 CMD: Req_RN, Read, Write, Lock, BlockWrite, BlockErase Reply: See state-transition tables CMD: Select CMD: Kill [valid handle & kill password = 0] Action: Return to ready Open Reply: Error code Reply: None. Note 1 CMD: Kill, Access [invalid handle] CMD: Query Reply: None Action: New round Reply: Notes 2, 3 CMD: Access [valid handle & valid access password] CMD: QueryRep, QueryAdjust Reply: handle when done 4-Apr-12 Action: Return to ready Copyright TecO 2007, Restricted Use 9
  • 10. Tag Requirements  EPC Gen2  ... 4-Apr-12 Copyright TecO 2007, Restricted Use 10
  • 11. Reader Requirements  Stage 1: Get # of collisions Get # of slots / frames Select product group*  Stage 2: Set # of slots/frames  Stage 3: Raw Reader/No Firmware Change Algorithm (i.e. No ACKs) * product distribution could also be estimated 4-Apr-12 Copyright TecO 2007, Restricted Use 11