862  RFID Standards and Protocols

862.1 Learning Objectives

By the end of this chapter, you will be able to:

• Identify key standards: Understand ISO 14443, ISO 15693, and EPC Gen2 standards
• Explain anti-collision: Describe how readers handle multiple tags simultaneously
• Understand EPC format: Interpret Electronic Product Code structure
• Apply standards knowledge: Select appropriate standards for different applications
• Optimize read performance: Configure anti-collision parameters for high-density environments

862.2 Prerequisites

Before diving into this chapter, you should be familiar with:

• RFID Introduction: Basic RFID concepts and terminology
• RFID Frequency Bands: Understanding of LF, HF, and UHF bands

862.3 RFID Standards Overview

%%{init: {'theme': 'base', 'themeVariables': {'primaryColor': '#E8F4F8', 'primaryTextColor': '#2C3E50', 'primaryBorderColor': '#16A085', 'lineColor': '#16A085', 'secondaryColor': '#FFF5E6', 'tertiaryColor': '#F0F0F0', 'noteTextColor': '#2C3E50', 'noteBkgColor': '#FFF5E6', 'textColor': '#2C3E50', 'fontSize': '14px'}}}%%
graph TB
    subgraph ISO["ISO STANDARDS"]
        ISO14443["ISO 14443<br/>HF Proximity Cards<br/>13.56 MHz, <10 cm"]
        ISO15693["ISO 15693<br/>HF Vicinity Cards<br/>13.56 MHz, <1 m"]
        ISO18000["ISO 18000<br/>Air Interface<br/>All frequencies"]

        ISO14443 --> TypeA["Type A: MIFARE<br/>Payments, Access"]
        ISO14443 --> TypeB["Type B: Passports<br/>eID, Government"]

        ISO15693 --> Library["Library Books<br/>Item Tracking"]

        ISO18000 --> Part6["Part 6: UHF<br/>860-960 MHz"]
        ISO18000 --> Part7["Part 7: Active<br/>433 MHz"]
    end

    subgraph EPC["EPC STANDARDS"]
        Gen2["EPC Gen2<br/>UHF 860-960 MHz"]
        Gen2Specs["640 Kbps data rate<br/>Anti-collision: Q-algorithm<br/>96/128-bit EPC<br/>Global supply chain"]

        Gen2 --> Gen2Specs
        Gen2 --> Apps["Applications:<br/>Retail (Walmart)<br/>Logistics<br/>Manufacturing"]
    end

    subgraph NFC["NFC STANDARDS"]
        NFCForum["NFC Forum<br/>ISO 14443 + extras"]
        NFCTypes["Type 1-5 Tags<br/>NDEF format"]

        NFCForum --> NFCTypes
        NFCTypes --> NFCApps["Mobile payments<br/>Pairing devices<br/>Smart posters"]
    end

    ISO14443 -.->|"Basis for"| NFCForum

    style ISO fill:#E8F4F8,stroke:#16A085,stroke-width:3px
    style EPC fill:#FFF5E6,stroke:#E67E22,stroke-width:3px
    style NFC fill:#F8E8E8,stroke:#2C3E50,stroke-width:3px

    style ISO14443 fill:#E8F4F8,stroke:#16A085,stroke-width:2px
    style ISO15693 fill:#E8F4F8,stroke:#16A085,stroke-width:2px
    style ISO18000 fill:#E8F4F8,stroke:#16A085,stroke-width:2px
    style Gen2 fill:#FFF5E6,stroke:#E67E22,stroke-width:2px
    style NFCForum fill:#F8E8E8,stroke:#2C3E50,stroke-width:2px

Figure 862.1: RFID standards hierarchy: ISO, EPC Gen2, and NFC Forum specifications

862.4 ISO Standards

862.4.1 ISO 14443 (HF - Proximity cards)

ISO 14443 defines the international standard for proximity cards operating at 13.56 MHz.

Key Specifications:

• Frequency: 13.56 MHz
• Range: <10 cm (intentionally short for security)
• Data Rate: 106-848 Kbps

Two Types:

• Type A (MIFARE): Developed by NXP, used in payment cards and access control
• Type B: Used in passports, government IDs, and secure applications

Applications:

• Contactless payment cards (Visa payWave, Mastercard PayPass)
• Building access control
• Public transport cards
• Electronic passports (ePassports)

862.4.2 ISO 15693 (HF - Vicinity cards)

ISO 15693 defines vicinity cards with longer range than ISO 14443.

Key Specifications:

• Frequency: 13.56 MHz
• Range: Up to 1 meter
• Data Rate: 1.65-26.48 Kbps

Applications:

• Library book tracking
• Item-level inventory
• Asset tracking
• Access control (when longer range is needed)

Question: Contactless payment cards (tap-to-pay) and many NFC phone interactions are based primarily on which standard?

Explanation: NFC builds on HF proximity communication defined in ISO 14443 (Type A/B). ISO 15693 is HF but designed for longer-range “vicinity” tags (e.g., libraries), and EPC Gen2/ISO 18000-6C is UHF for supply chain.

862.4.3 ISO 18000 (All frequencies)

ISO 18000 is a family of standards covering all RFID frequency bands.

Key Parts:

• Part 2: Below 135 kHz (LF)
• Part 3: 13.56 MHz (HF)
• Part 6: 860-960 MHz (UHF) - harmonized with EPC Gen2
• Part 7: 433 MHz (Active)

862.5 EPC Gen2 (UHF Standard)

EPCglobal Gen2 (also known as ISO 18000-6C) is the dominant UHF RFID standard for supply chain applications.

Key Features:

• Developed by: GS1 (same organization behind barcodes)
• Frequency: 860-960 MHz (regional variations)
• Data Rate: Up to 640 Kbps
• Anti-collision: Q-algorithm (slotted ALOHA)
• EPC Length: 96-bit or 128-bit

862.5.1 Electronic Product Code (EPC) Structure

The EPC is a unique identifier for each tagged item:

EPC: 3034257BF400B7800011EAE3

Structure:
| Header | Filter | Partition | Company | Item | Serial |
|   8    |   3    |     3     |  24-40  | 4-24 | 36-38  |

Components:

• Header: Identifies EPC type and length
• Filter Value: Product type classification
• Partition: How bits are divided between company and item
• Company Prefix: GS1 assigned company identifier
• Item Reference: Product SKU or item type
• Serial Number: Unique per item (unlike barcodes!)

{
  const container = document.getElementById('kc-rfid-std-1');
  if (container && typeof InlineKnowledgeCheck !== 'undefined') {
    container.innerHTML = '';
    container.appendChild(InlineKnowledgeCheck.create({
      question: "A global shipping company is deploying RFID across its supply chain spanning 40 countries. They need tags that will work with readers from multiple vendors, support a standardized 96-bit identifier format for tracking millions of unique items, and enable reading hundreds of tags per second when scanning shipping containers. Which standard should they specify?",
      options: [
        {text: "ISO 14443 Type A - globally standardized for contactless applications", correct: false, feedback: "ISO 14443 is an HF proximity standard (<10cm range) designed for contactless smart cards, not supply chain logistics. Its short range makes it unsuitable for scanning containers with hundreds of items."},
        {text: "EPC Gen2 (ISO 18000-6C) - UHF supply chain standard with standardized EPC format and high-speed anti-collision", correct: true, feedback: "Correct! EPC Gen2 (also known as ISO 18000-6C) is THE global supply chain standard. It defines the 96-bit Electronic Product Code format, Q-algorithm anti-collision for reading 200+ tags/second, and ensures interoperability across all major RFID reader manufacturers worldwide."},
        {text: "ISO 15693 - international standard with good multi-tag support", correct: false, feedback: "ISO 15693 is an HF vicinity standard with limited range (~1m) and lower throughput than UHF. It cannot read hundreds of tags per second and lacks the standardized EPC identifier format."},
        {text: "Proprietary UHF protocols - better performance than standards-based systems", correct: false, feedback: "Proprietary protocols would create vendor lock-in and interoperability problems across 40 countries."}
      ],
      difficulty: "medium",
      topic: "rfid-epc-standards"
    }));
  }
}

862.6 Anti-Collision Protocols

When multiple tags are in the reader’s field, they must respond without interfering with each other.

862.6.1 The Problem: Tag Collision

Imagine 200 people all trying to answer a question at once - you can’t understand anyone! RFID faces the same challenge when hundreds of tags try to respond simultaneously.

862.6.2 EPC Gen2 Q-Algorithm

The Q-algorithm uses slotted ALOHA with adaptive slot counts:

1. Reader announces Q value (number of slots = 2^Q)
2. Each tag randomly selects a slot
3. Reader queries each slot in sequence
4. Tags that collide wait for next round
5. Reader adjusts Q based on collision rate

Example with Q=4 (16 slots):

• 50 tags in field, each picks random slot 0-15
• Average 3.1 tags per slot
• Many collisions in round 1
• Unread tags retry in round 2 with fewer competitors
• After 3-4 rounds, all tags read

862.6.3 Optimizing Q Value

Tag Count	Optimal Q	Slots	Expected Rounds
10	4	16	2
50	6	64	2-3
200	8	256	3-4
500	9	512	4-5

Formula: Optimal Q = ceil(log2(expected_tags))

RFID Anti-Collision

Figure 862.2: RFID anti-collision algorithm enables reading hundreds of tags simultaneously

{
  const container = document.getElementById('kc-rfid-std-2');
  if (container && typeof InlineKnowledgeCheck !== 'undefined') {
    container.innerHTML = '';
    container.appendChild(InlineKnowledgeCheck.create({
      question: "A distribution center has deployed a UHF RFID portal to scan pallets with 150 tagged cases each. The reader is configured with Q=5 (32 time slots). During testing, only 110 of 150 tags are consistently read (73% read rate). The forklift dwells in the read zone for 1.5 seconds. What is the most likely cause and solution?",
      options: [
        {text: "Reader power is too low - increase transmit power to reach all tags", correct: false, feedback: "Power affects range, not collision handling. With 150 tags trying to respond in 32 slots (Q=5), many tags will select the same slot and collide regardless of signal strength."},
        {text: "Q value is too low causing excessive collisions - increase Q to 8 (256 slots) to reduce collision probability", correct: true, feedback: "Correct! With Q=5 (32 slots) and 150 tags, on average 4-5 tags compete for each slot, causing massive collisions. The optimal Q = ceil(log2(150)) = 8, providing 256 slots so most tags get unique slots."},
        {text: "Tags are defective - replace the 40 unread tags with new ones", correct: false, feedback: "The ~40 missed tags change randomly each scan (different tags miss each time), indicating a protocol problem, not defective hardware."},
        {text: "Antenna polarization is wrong - switch from linear to circular polarization", correct: false, feedback: "While polarization affects reads of randomly oriented tags, the 73% read rate with consistent patterns points to collision problems, not orientation issues."}
      ],
      difficulty: "hard",
      topic: "rfid-anti-collision"
    }));
  }
}

{
  const container = document.getElementById('kc-rfid-std-3');
  if (container && typeof InlineKnowledgeCheck !== 'undefined') {
    container.innerHTML = '';
    container.appendChild(InlineKnowledgeCheck.create({
      question: "A warehouse portal reads pallets containing 500 tagged items. With the current Q=7 setting (128 slots), they achieve 94% read rate in the 2-second dwell time. Management wants 99%+ read rate. The engineer calculates that Q=9 (512 slots) would reduce collisions but worries about the time impact. Each inventory round takes approximately Q*2ms. Can they achieve 99%+ with the current 2-second dwell time by changing only the Q value?",
      options: [
        {text: "Yes - Q=9 with 512 slots will eliminate collisions and achieve 99%+ in a single pass", correct: false, feedback: "While Q=9 reduces collisions, one round takes 512*2ms = 1024ms (over 1 second). With only 2 seconds available, you get fewer than 2 complete rounds."},
        {text: "No - optimal Q=9 means each round takes 1+ second, leaving time for only 1-2 rounds which is insufficient for 99%+ on 500 tags", correct: true, feedback: "Correct! Q=9 (512 slots) * 2ms = 1024ms per round. In 2 seconds, only ~2 rounds are possible. The tradeoff between collision reduction and round time means Q=8 with more passes might work better, or the dwell time needs to increase."},
        {text: "Yes - set Q=12 to virtually eliminate all collisions in one round", correct: false, feedback: "Q=12 means 4096 slots * 2ms = 8.2 seconds per round! This far exceeds the 2-second dwell time."},
        {text: "No - the Q algorithm only works for up to 256 tags, so 500 tags is beyond its capability", correct: false, feedback: "The Q algorithm works for any number of tags - Q just sets the number of slots. The issue is the time/collision tradeoff."}
      ],
      difficulty: "hard",
      topic: "rfid-anti-collision-optimization"
    }));
  }
}

862.7 NFC Standards

NFC (Near Field Communication) builds on ISO 14443 with additional features for smartphone interaction.

862.7.1 NFC Forum Tag Types

Type	Standard	Memory	Speed	Typical Use
Type 1	Topaz	96-2,048 bytes	106 Kbps	Simple URLs
Type 2	NTAG	48-2,048 bytes	106 Kbps	Smart posters
Type 3	FeliCa	1-4 KB	212/424 Kbps	Transit cards
Type 4	ISO 14443	Up to 32 KB	Up to 424 Kbps	Payment cards
Type 5	ISO 15693	Up to 64 KB	26.48 Kbps	Longer range

862.7.2 NDEF (NFC Data Exchange Format)

NDEF provides a standard way to encode data on NFC tags:

• URL Records: Links to websites
• Text Records: Plain text messages
• Smart Poster: Combines URL, text, and icons
• MIME Records: Any file type
• Android Application Records (AAR): Launch specific apps

862.8 Common Misconception

WarningCommon Misconception: “UHF RFID Always Works Better Because of Longer Range”

The misconception: UHF (860-960 MHz) can offer meter-scale reads, so it’s tempting to default to UHF for every project.

Why it’s wrong: RFID performance is strongly environment-dependent. Metal surfaces and water-rich products can detune tags, create deep fades, and distort the read zone.

A practical way to choose:

• Mostly metal or near liquids -> start by evaluating LF/HF, or UHF with on-metal tags
• Open/dry environment + bulk inventory -> UHF is often a strong fit
• Intentional proximity or smartphone compatibility -> HF/NFC
• Very long range / RTLS -> consider active tags

Lesson: Range is only one parameter. Choose based on materials + workflow + compliance, then validate with a pilot.

862.9 Cross-Hub Connections

NoteCross-Hub Connections: RFID Learning Resources

Explore RFID across the learning ecosystem:

• Knowledge Map: See how RFID concepts connect to wireless sensor networks, NFC, and identification systems
• Quizzes Hub: Test your RFID knowledge with frequency selection, tag types, and anti-collision protocol quizzes
• Simulations Hub: Experiment with RFID range calculators and frequency band comparisons
• Videos Hub: Watch visual explanations of electromagnetic induction and backscatter modulation

862.10 Summary

This chapter covered RFID standards and protocols:

• ISO 14443: HF proximity cards for payments and access control (<10 cm)
• ISO 15693: HF vicinity cards for library and item tracking (~1 m)
• EPC Gen2: UHF supply chain standard with 96-bit EPCs and Q-algorithm anti-collision
• NFC Forum: Standards for smartphone interaction building on ISO 14443
• Anti-collision: Q-algorithm enables reading hundreds of tags per second
• Q optimization: Match Q value to expected tag count for best performance

862.11 What’s Next

Continue to RFID Design and Deployment to learn about decision frameworks, worked examples, and common deployment pitfalls.

NoteRelated Chapters

RFID Series:

• RFID Introduction - Basic concepts and terminology
• RFID Tag Types - Passive, active, semi-passive tags
• RFID Frequency Bands - LF, HF, UHF comparison
• RFID Design and Deployment - Decision framework

Related Standards:

• NFC Fundamentals - NFC-specific details
• 6LoWPAN Overview - Another IEEE-based protocol