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.

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.

Access Control: Limits who can access data, but doesn't make it unreadable.
Authentication: Validates user/device identity, but not focused on data confidentiality.
Authorization: Determines the actions a user is allowed, separate from securing the data itself.
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.

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.

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.