955  IEEE 802.15.4: Quiz Bank Part 2

955.1 Overview

This quiz bank section contains comprehensive review questions covering advanced IEEE 802.15.4 concepts. The questions are organized into three focused topic areas for better learning and review.

Total Questions: 8 comprehensive MCQs with detailed explanations Estimated Time: 45-60 minutes Difficulty: Intermediate to Advanced

NoteNavigation

Overview: Quiz Bank Overview - Learning objectives and study strategy

Part 2 Quiz Sections (Current): - Deployment and Power Management - 2 questions - Superframe Structure and Device Types - 4 questions - Security and Interference Management - 2 questions

Other Parts: - Part 1 - Comprehensive Review Questions 1-60 - Part 3 - Visual Reference Gallery

Study Materials: - 802.15.4 Fundamentals - Core concepts - 802.15.4 Topic Review - Quick reference

955.2 Quiz Sections

955.2.1 Deployment and Power Management

2 Questions | 15-20 minutes

Topics covered: - Battery life calculation - Duty cycle analysis for warehouse sensor deployment with realistic factors (self-discharge, voltage drop) - Variant selection - IEEE 802.15.4g vs 802.15.4-2003 for industrial factory deployment considering range, frequency, and cost

Key concepts: Power budget, duty cycle optimization, sub-GHz advantages, infrastructure cost analysis.

955.2.2 Superframe Structure and Device Types

4 Questions | 25-30 minutes

Topics covered: - Superframe with GTS - CAP percentage calculation and slot allocation for HVAC control in beacon-enabled mode - RFD buffer clearing - Frame packing efficiency for healthcare patient monitor scenario - Superframe timing - SO/BO calculations for industrial sensor networks - FFD vs RFD RAM - Device type memory requirements and routing capability limitations

Key concepts: GTS allocation, beacon interval timing, device type architecture, frame packing optimization.

955.2.3 Security and Interference Management

2 Questions | 12-15 minutes

Topics covered: - Security overhead - AES-128 CCM encryption with MIC-64 and frame structure implications - Channel hopping - Thread network adaptive interference management with PER-based blacklisting

Key concepts: Security header structure, MIC authentication, PER monitoring, adaptive channel selection.

955.3 Learning Path

955.3.2 Quick Navigation Table

Section Questions Topics Time
Deployment/Power 2 Battery life, variant selection ~18 min
Superframe/Devices 4 GTS, SO/BO, FFD/RFD ~28 min
Security/Interference 2 AES-128, channel hopping ~14 min
Total 8 All Part 2 topics ~60 min

955.4 Key Concepts Covered

955.4.1 Deployment and Power

  • Ultra-low power operation: < 1% duty cycle enables multi-year battery life
  • Variant selection: 802.15.4g (sub-GHz) offers 40x lower infrastructure cost for industrial environments
  • Realistic factors: Self-discharge, voltage drop, and MCU overhead affect practical battery life

955.4.2 Superframe Structure

  • Timing formulas:
    • Superframe Duration (SD) = aBaseSuperframeDuration x 2^SO
    • Beacon Interval (BI) = aBaseSuperframeDuration x 2^BO
    • Active percentage = SD / BI
  • GTS allocation: Guaranteed slots reduce CAP but provide deterministic access
  • Duty cycle trade-offs: Higher SO = more capacity, higher power; Higher BO = better battery, higher latency

955.4.3 Device Types

  • FFD (Full Function Device): Coordinator/router/end device, full MAC, routing tables
  • RFD (Reduced Function Device): End device only, talks to FFD only, no routing
  • RAM requirements: FFD 64-256 KB (routing + buffers), RFD 8-32 KB (simple MAC)
  • Frame packing: Fit complete sensor readings (3 x 32 bytes = 96 bytes in 102-byte payload)

955.4.4 Security

  • AES-128 CCM: ~14 bytes overhead (security header + 8-byte MIC)
  • Security levels: 0 (none) to 7 (ENC-MIC-128)
  • Protection provided: Anti-replay (frame counter), authentication (MIC), confidentiality (encryption)

955.4.5 Interference Management

  • PER monitoring: Track packet error rate per channel over sliding window
  • Blacklisting threshold: > 50% PER for 5 consecutive hops
  • Recovery time: 30-60 seconds for adaptive channel blacklisting
  • Thread advantage: Network-layer intelligence built on 802.15.4 primitives

955.5 What’s Next

After completing Part 2: - Quiz Bank Part 1 - Addressing, tree topologies, and basic calculations - Quiz Bank Part 3 - Visual reference gallery and summary - 802.15.4 Comprehensive Review - Complete specification coverage