CWISA-102 Certified Wireless IoT Solutions Administrator Question and Answers

• OFDM vs. OFDMA:

References

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

• 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:

References:

• 60GHz Propagation Characteristics: Technical papers discussing oxygen absorption and its influence on range limitations.
• Millimeter-wave (mmWave) Communication: Overviews highlighting the challenges and short-range applications of 60GHz systems.

• Encryption vs. Other Options:
• How encryption works: Encryption uses algorithms and keys to turn plaintext into unreadable ciphertext. Only those with the correct key can decrypt it.
• Data in motion vs. data at rest: Encryption protects sensitive information both when transmitted over the wireless network and when stored on devices.

References:

• Encryption standards and protocols: Resources on common wireless encryption types (WPA2, WPA3, TLS) and their implementation.

• 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.

References:

• LoRa Modulation: Technical explanations of Chirp Spread Spectrum (CSS).
• LoRaWAN Specification: Official documentation detailing the network architecture and MAC layer functions.
• OSI Model: Descriptions of the Data Link layer and its role in networking.

• Successful Deployment Depends on Buy-In: A final customer meeting signifies the handover phase. Achieving stakeholder agreement ensures everyone impacted by the solution has a voice and feels their concerns are addressed.
• Sign-Off and Formal Acceptance: Stakeholders often need to formally "sign-off" on a project's completion, indicating satisfaction and readiness for operational use.
• Other Options: While Important, Not the Primary Goal:

References:

• Project Management Methodologies: Emphasis on stakeholder involvement & acceptance criteria.
• ITIL (Change Management): Materials on getting approval before a system goes live.

• Cloud-based applications drive bandwidth usage: Applications like Google Suite, Microsoft 365, and video conferencing (Zoom, Teams) are commonly used in educational settings. These rely on cloud servers, requiring significant downloads and uploads.
• Shift towards online learning: More schools are utilizing online learning platforms and resources, further increasing their dependence on cloud-based solutions.
• Streaming, torrents, wearables less impactful: Streaming music and torrent sites can contribute, but their impact is generally less significant. Wearables in education are still niche despite their potential.

References

• Trends in education technology: Reports on the rise of cloud-based learning platforms in schools.
• Network usage studies in schools: Research on bandwidth usage patterns can confirm the primary drivers of traffic in educational settings.

• 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

• 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):

• IP Ratings & Manufacturing: IP66 provides:
• 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

• QAM Constellations: QAM (Quadrature Amplitude Modulation) uses a constellation diagram where points represent unique combinations of amplitude and phase.
• Bits per Symbol: The number in QAM-XX indicates the number of points:
• Higher Data Rates: More points in the constellation enable transmitting more bits per symbol, leading to higher data rates at the same bandwidth.

References

• QAM: https://en.wikipedia.org/wiki/Quadrature_amplitude_modulation

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

References

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

• PoE Splitter: A PoE splitter separates power and data from a PoE-enabled Ethernet cable, allowing the powering of non-PoE devices.
• Other PoE Devices:

• 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:

References

• IETF Website: https://www.ietf.org/
• OSI Model: https://en.wikipedia.org/wiki/OSI_model

• ITU's Mandate: The International Telecommunication Union (ITU) is a specialized agency of the United Nations focused on global information and communication technologies (ICTs).
• Radio Spectrum Regulation: A core ITU function is allocating radio spectrum bands and satellite orbits to prevent harmful interference between different countries and technologies. This coordination is essential for the orderly use of wireless communications worldwide.
• Other ITU Roles: While involved in standard-setting and establishing best practices, options A and D are less precise than the ITU's spectrum coordination focus.

References:

• ITU Website: (https://www.itu.int/en/) Outlines its activities and governance of radio spectrum.
• ITU Radio Regulations: The international treaty governing the use of the radio-frequency spectrum.

• Lab Purpose: Wireless testing labs offer controlled settings to:
• Other Benefits (While not the primary benefit):

References

• Benefits of IT Labs: Can be extended from wireless to broader IT experimentation and learning. (Articles on this topic are readily available)

• 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:

References

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

• ZigBee Channel Spacing: ZigBee channels in the 2.4 GHz band are spaced 5 MHz apart. This helps manage interference in the crowded 2.4 GHz spectrum.