The Certified Wireless IoT Solutions Administrator(2025 Edition) (CWISA-103)

The concept described is  Free Space Path Loss (FSPL) . FSPL refers to the reduction in power density of an electromagnetic wave as it propagates through a clear, unobstructed path in free space. This weakening of the signal is due to the spreading of the wavefront as it travels, causing the power to be distributed over a larger area. The FSPL can be calculated using the Friis Transmission Equation, which shows that the received power decreases with the square of the distance from the transmitter. This concept is fundamental to understanding the behavior of RF signals in various communication systems, including wireless IoT, where the signal strength at the receiver is a critical factor for reliable data transmission.

PHP's Cross-Platform Nature:  PHP originated for server-side web development, but also has a command-line interface (CLI) enabling its use for scripts and automation tasks.

Other Options:

Some  languages are OS-specific (but less frequent with modern scripting languages) .

Many languages work in web  or  command line, not  both  like PHP.

Requirements Drive Decisions:  The decision between wired or wireless must align with the solution's overall purpose, performance targets, and operational constraints.

Key Considerations:

Reliability:  Does the application require guaranteed connectivity? (Wired may be favored).

Installation Cost:  Can extensive cabling be done, or is it prohibitively expensive? (Wireless may be favored).

Flexibility and Scalability:  Is node placement likely to change in the future? (Wireless may be favored).

Other Factors are Important, But Secondary:  Distance, PoE availability, specific applications all matter, but they are assessed  within the context  of the overarching business needs.

Consumer Smart Devices Limitation:  Many consumer-oriented smart devices are designed for simplicity and cost-effectiveness, leading to reliance on the crowded 2.4 GHz band.

Consequences:

High Interference:  Increased potential for interference from Wi-Fi and other 2.4 GHz devices.

Limited scalability:  Performance and reliability may degrade in busy wireless environments.

SINR vs. SNR:

SNR (Signal-to-Noise Ratio):  Measures the power of the desired signal relative to background noise.

SINR (Signal-to-Interference-plus-Noise Ratio):  Considers both background noise  and  interference from other signals operating on the same frequency.

Practical Importance:  SINR is a more realistic indicator of real-world signal quality in wireless environments where interference is a significant factor.

References

SINR:   https://en.wikipedia.org/wiki/Signal-to-interference-plus-noise_ratio

SNR:   https://en.wikipedia.org/wiki/Signal-to-noise_ratio

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

Firmware Definition:  Firmware is a type of software embedded in hardware devices. It provides low-level instructions that control the basic operations and initialization of the device.

ROM Storage:  Firmware is typically stored in Read-Only Memory (ROM) or other forms of non-volatile memory, meaning it persists even when the device is powered off.

Functions:

Booting:  Initiates the hardware and loads the operating system.

Hardware Control:  Provides an interface between the hardware and the operating system.

BIOS:  The firmware on PCs is often referred to as BIOS (Basic Input/Output System).

References

Firmware Explanation:   https://en.wikipedia.org/wiki/Firmware

ROM:   https://en.wikipedia.org/wiki/Read-only_memory

Privilege Creep Defined:  Gradual accumulation of excessive permissions over time, often due to users changing roles or access needs not being adjusted accordingly.

Other Terms:

Privilege Escalation: A malicious act of obtaining higher-than-authorized access.

Improper Delegation/Grouping: Faulty permission assignment, but not the gradual accretion aspect.

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:

Scope definition typically happens much earlier

Solutions may or may not include wearables

Power supply should already be planned