Which three factors impact indoor WLAN coverage areas? (Choose three.)

The coverage area of an indoor WLAN is fundamentally determined by the strength and shape of the radio frequency (RF) signal.

1. AP Tx power (Transmit Power) is the initial strength of the signal leaving the access point. A higher power level allows the signal to travel farther and better penetrate obstacles, directly increasing the potential coverage radius.

2. Antenna pattern defines the shape, directionality, and gain of the RF signal radiated by the antenna. An omnidirectional pattern provides 360-degree horizontal coverage, while a directional pattern focuses energy in a specific direction.

3. AP orientation dictates how the antenna pattern is projected into the physical space. For instance, a ceiling-mounted AP with an integrated omnidirectional antenna is designed to radiate downwards and outwards; mounting it on a wall would drastically alter the effective coverage area.

B. Earth bulge: The curvature of the Earth is a factor only in very long-distance outdoor wireless links (spanning many kilometers) and is completely negligible for indoor environments.

E. Antenna diversity: This is a technique that uses multiple antennas to improve signal reliability and mitigate the effects of multipath fading, enhancing performance within the coverage area rather than defining its primary boundary.

F. Spatial multiplexing: This is a MIMO (Multiple-Input, Multiple-Output) technology that increases data throughput by sending multiple data streams simultaneously. It is a capacity enhancement, not a coverage extension mechanism.

1. RUCKUS Wi-Fi Best Practices Design Guide, Version 2.0:

Page 12, Section "AP Transmit Power": "Transmit power is one of the most important settings in a WLAN... Setting transmit power too high can cause co-channel interference... Setting it too low can create coverage holes." This confirms the direct impact of Tx power (A) on coverage.

Page 13, Section "AP and Antenna Placement": "APs with integrated antennas should be mounted according to manufacturer recommendations to achieve the desired coverage pattern." This directly links AP orientation (C) and the resulting coverage pattern (D) to proper design.

2. RUCKUS Indoor AP Wi-Fi 6 (802.11ax) Portfolio Datasheet:

Page 6, "R750 Antenna Radiation Patterns": This document provides detailed diagrams of the antenna patterns for specific AP models. The patterns clearly show that signal strength varies significantly depending on the angle and plane (azimuth/elevation), underscoring the importance of both the inherent antenna pattern (D) and the AP's physical orientation (C).

3. Kurose, J. F., & Ross, K. W. (2017). Computer Networking: A Top-Down Approach (7th ed.). Pearson.

Chapter 7.2, "Wireless Links and Network Characteristics": This chapter discusses signal propagation, noting that signal strength decreases with distance. The initial signal strength is determined by the transmission power. The chapter also explains how antenna design (pattern) focuses this power. This foundational knowledge supports the roles of Tx power (A) and antenna pattern (D) in determining coverage.