CWNP CWISA-103 Certified Wireless IoT Solutions Administrator(2025 Edition) Exam Practice Test

Coexistence Priority: Frequency coordination is the most critical aspect in ensuring that multiple wireless solutions function without significant interference.

Impact of Interference: Uncoordinated frequencies lead to:

Signal degradation: Reduced network performance and reliability.

Data errors and retransmissions: Inefficient operation and higher battery drain on devices.

Wireless Transceiver: A transceiver is a combination of a transmitter and receiver used for wireless communication.

Radio: The radio is the primary component responsible for:

Modulation: Encoding data onto a carrier wave.

Demodulation: Extracting data from a received signal.

Transmission/Reception: Handling the actual sending and receiving of modulated signals over the air.

References

Transceiver: https://en.wikipedia.org/wiki/Transceiver

OFDM vs. OFDMA:

OFDM (Orthogonal Frequency-Division Multiplexing): Divides a channel into multiple subcarriers for data transmission.

OFDMA (Orthogonal Frequency-Division Multiple Access): Extends OFDM by allowing multiple users to share subcarriers simultaneously, improving efficiency and spectral utilization.

References

OFDM: https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiplexing

OFDMA: https://en.wikipedia.org/wiki/Orthogonal_frequency-division_multiple_access

Bottom-Up Troubleshooting: The OSI model provides a structured diagnostic approach. Starting at Layer 1 ensures basic physical connectivity issues are ruled out first.

MQTT Relies on IP: MQTT operates at a higher layer of the OSI model, relying on TCP/IP (Layers 4 and 3) for communication. Problems at the physical layer will disrupt everything built upon it.

Checking the Fundamentals: Before investigating complex application issues (MQTT), verify cables, link lights, Wi-Fi signal strength, etc.

Wi-Fi and Zigbee Interference: Both can operate in the 2.4 GHz band, leading to potential interference that degrades performance for both networks.

5 GHz Advantages:

Less crowded: Fewer devices operate in the 5 GHz band, reducing interference potential.

Wider Channels: 5 GHz supports wider channels, enabling higher data throughput for Wi-Fi.

Decibel (dB): A logarithmic unit expressing ratios of power or signal strength. It's used in RF contexts due to the wide range of signal levels encountered.

Examples:

dBm: Decibels relative to one milliwatt (power measurement).

dBi: Decibels relative to an isotropic antenna (antenna gain).

References

Decibel: https://en.wikipedia.org/wiki/Decibel

WWAN (Wide-Area Wireless Network): WWANs provide connectivity over extensive geographic areas, typically covering regions or even entire countries.

Cellular Technology: WWANs often rely on cellular networks (3G, 4G, 5G) offered by mobile carriers.

References

WWAN: https://en.wikipedia.org/wiki/Wireless_wide_area_network

Most Vulnerable In Transit: Sensitive data (passwords, health information, etc.) is most susceptible to interception while being sent over a wireless network. Encryption is crucial at this stage.

Encryption at Rest and in Memory: While also important, these are often handled with different cryptographic techniques depending on the system.

60GHz Absorption: The 60GHz band experiences significant signal attenuation due to absorption by oxygen molecules in the atmosphere. This severely restricts the usable range of wireless systems operating in this frequency.

Why Other Options Don't Apply:

Atmospheric Scattering: Impacts longer wavelength transmissions, less significant at 60GHz.

Solar Radiation: Can cause interference on some frequencies, but not a primary range limitation at 60GHz.

Rain Fade: Primarily affects higher frequencies (above 10GHz), but its impact is less severe than oxygen absorption at 60GHz.

IP Ratings & Manufacturing: IP66 provides:

Dust-tight: (First '6') Complete protection against dust ingress.

Powerful Water Jets: (Second '6') Protection against strong water jets from any direction.

Harsh Manufacturing Environments: IP66 is common due to dust, dirt, and potential exposure to liquids during cleaning or spills.

References

IP Ratings: https://en.wikipedia.org/wiki/IP_Code

Attenuation: Describes the progressive loss of signal strength as it travels through a medium (like air, cables, walls). It's caused by factors like absorption, distance, and obstacles.

Other Phenomena:

Diffraction: Bending of waves around obstacles.

Reflection: Waves bouncing off surfaces.

**Scattering: ** Waves dispersing in multiple directions.

References

Attenuation: https://en.wikipedia.org/wiki/Attenuation

JSON Fundamentals: JSON (JavaScript Object Notation) is a text-based format for representing data in a structured, yet flexible way. Its key features are:

Key-Value Pairs: Information is organized as "key":"value" pairs, making it human-readable.

Plaintext: JSON is not encrypted, ensuring easy parsing across different systems.

JSON vs. Other Options

Not Encrypted: Security must be handled at a higher layer if needed.

Not Optimized for Databases: While JSON can be stored in databases, it's designed for data exchange, not database structure.

Not Inherently Compressed: Compression can be used with JSON, but it's not a core feature.

Legacy Support: The primary reason to continue using older wireless technologies is the need to connect with devices that don't support newer standards (e.g., old sensors or equipment).

Other Reasons (Not as Strong):

Cost: Replacing legacy devices can be expensive.

Reliability: Some legacy technologies might be well-proven in specific settings.

LoRa: This refers to the underlying radio modulation technique using Chirp Spread Spectrum (CSS). It defines how data is physically encoded onto the wireless signal.

LoRaWAN: This is the network protocol built on top of LoRa. It manages device communication, network topology, and aspects like security. It operates at the MAC sublayer of the Data Link layer (Layer 2) of the OSI model

LoRa vs. LoRaWAN: Key takeaway is that LoRa is the physical layer technology, while LoRaWAN adds the networking layer for management.

IETF's Focus: The Internet Engineering Task Force (IETF) primarily develops and standardizes internet protocols operating at the Network Layer (Layer 3) and above in the OSI model.

Key Protocols: Some prominent IETF-developed protocols include:

IP (Internet Protocol): Foundation of internet addressing and routing.

TCP (Transmission Control Protocol): Reliable, connection-oriented data transport.

UDP (User Datagram Protocol): Connectionless, best-effort data transport.

DNS (Domain Name System): Translates domain names into IP addresses.

HTTP (Hypertext Transfer Protocol): Web communication.

References

IETF Website: https://www.ietf.org/

OSI Model: https://en.wikipedia.org/wiki/OSI_model

Customization and Integrations: The presence of APIs often suggests a system is integrated with other platforms or has custom-built elements.

Understanding Dependencies: Documenting used APIs helps clarify how different parts of the system interact and where potential issues might arise.

Troubleshooting Efficiency: Detailed API documentation aids in resolving problems, allowing staff to assess interconnected systems effectively.

Knowledge transfer: Future support teams won't have to reverse-engineer the system; documentation ensures smooth handover and understanding.

LoRa Modulation: LoRa (Long Range) is a proprietary wireless technology that utilizes Chirp Spread Spectrum (CSS) modulation.

CSS Characteristics:

Spread spectrum technique for resilience against interference.

Chirps (frequency sweeps) enable operation below the noise floor for long range.

References

LoRa: https://en.wikipedia.org/wiki/LoRa

Chirp Spread Spectrum (CSS): https://en.wikipedia.org/wiki/Chirp_spread_spectrum

Free Space Path Loss (FSPL): Describes how a radio signal weakens as it travels through open space, even without obstacles. It's caused by the signal spreading out, resulting in decreased power density at the receiver.

Calculation: FSPL depends on distance and frequency.

References

Free Space Path Loss: https://en.wikipedia.org/wiki/Free-space_path_loss

Smart Building Core Benefit: Smart building technologies primarily aim to optimize a building's operational efficiency through automation and data-driven insights.

Efficiency Examples:

Energy Management: Automated lighting and HVAC control based on occupancy and environmental conditions.

Maintenance: Predictive maintenance through IoT sensors reduces downtime.

Space Utilization: Optimization of space allocation based on real-time usage patterns.

References

Smart Buildings: https://en.wikipedia.org/wiki/Smart_building

Articles on Benefits of Smart Buildings: A quick search will yield many resources detailing these advantages.

SBCs (Single Board Computers): Designed as standalone, small-form-factor computers. They often include:

Display Interfaces: HDMI, DisplayPort, etc.

Input Connections: USB for keyboards, mice, etc.

General Purpose Functionality: Can run a full operating system for wider applications.

Controller Boards: Focus on controlling specific hardware or systems.

Limited direct I/O: Limited connectors for displays/input devices.

Specialized tasks: Designed for embedded applications within larger systems.

References

SBC Examples: https://www.raspberrypi.org/ , https://www.beagleboard.org/

Controller Board Examples: https://www.arduino.cc/