CWNA-109 Exam Dumps : Certified Wireless Network Administrator

The feature of 802.11ax (HE) that provides this functionality is OFDMA. OFDMA stands for Orthogonal Frequency Division Multiple Access and is a technology that allows multiple devices to communicate simultaneously on the same channel in the same BSS. OFDMA works by dividing a channel into smaller subchannels called Resource Units (RUs), which are composed of groups of subcarriers or tones. Each RU can be assigned to a different device based on its bandwidth requirement and signal quality. This way, OFDMA can increase the efficiency and capacity of the channel by reducing overhead, contention, and latency. OFDMA can also support both uplink and downlink multi-user transmissions using trigger frames and buffer status reports. 6 GHz support, TWT, and Wi-Fi-LTE are not features of 802.11ax that provide this functionality. References: [CWNP Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 226; [CWNA: Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109], page 216.

To calculate the EIRP at the antenna element, we need to add the transmitter output power, subtract the cable loss, and add the antenna gain. All these values need to be converted to dBm first, if they are not already given in that unit. In this case, we have:

Transmitter output power = 50 mW = 10 log (50) dBm = 16.99 dBm Cable loss = 3 dB Antenna gain = 9 dBi

EIRP = Transmitter output power - Cable loss + Antenna gain EIRP = 16.99 - 3 + 9 EIRP = 22.99 dBm

Rounding up to the nearest integer, we get 23 dBm as the EIRP at the antenna element12. References: CWNA-109 Study Guide, Chapter 2: Radio Frequency Fundamentals, page 92; CWNA-109Study Guide, Chapter 2: Radio Frequency Fundamentals, page 88.

A pre-design site visit in preparation for a predictive wireless LAN design is essential for gathering physical and environmental data about the site. The key tasks to be performed during such a visit include:

• Evaluating Building Materials: Different materials (concrete, glass, wood, etc.) have varying effects on RF signal propagation. Understanding the materials present helps in accurately predicting how signals will behave within the environment.
• Floor Plan Verification: Ensuring that the floor plan documents are an accurate representation of the actual building layout is crucial. Discrepancies between the floor plans and the physical layout can lead to inaccuracies in the predictive design.

The other options, while potentially valuable in other contexts, are not directly related to preparing for a predictive design:

• Installing APs(option A) for testing co-channel interference is more aligned with an active site survey rather than a pre-design visit for a predictive design.
• Collecting information about security requirements(option B) is important but is not directly related to the physical aspects of the site that would impact a predictive design.
• Testing antenna types(option C) would typically be part of an active site survey or the actual deployment phase, not a pre-design visit for predictive modeling.

Therefore, option D is the correct answer, focusing on evaluating physical aspects crucial for accurate predictive modeling.

References:

• CWNA Certified Wireless Network Administrator Official Study Guide: ExamCWNA-109, by David D. Coleman and David A. Westcott.
• Best practices for conducting pre-design site visits in wireless network planning.