Top Interview Questions for Wireless Site Survey Engineers

1

Do you have any experience managing WLAN security?

Reference answer

The candidate should discuss their knowledge of WLAN security measures, such as encryption standards, authentication methods, and intrusion detection.

2

Imagine a scenario where an RF system experiences intermittent faults. What troubleshooting techniques would you employ to identify and rectify these faults?

Reference answer

The candidate should provide strategies to identify and solve intermittent issues, which are often challenging. The response should illustrate their analytical skills and ability to work with complex and unpredictable RF environments.

3

What is the difference between a plan and a map?

Reference answer

While both plans and maps depict geographic features, they differ in scope and purpose: - Plan: A plan is a detailed representation of a small area, such as a building site or a property. It focuses on specific details and dimensions, usually for engineering or construction purposes. - Map: A map covers a larger area, typically showing broader geographic features like roads, rivers, and cities. It is generally designed for navigation or general information purposes.

4

Do you have any experience with VoIP systems and technologies?

Reference answer

Voice over Internet Protocol has become an integral part of many businesses. Having someone who understands VoIP systems and technologies can be a significant advantage for any modern business.

5

What is the role of modulation in wireless communication?

Reference answer

Modulation is the process of varying a carrier signal's properties (amplitude, frequency, or phase) to encode information for transmission. It allows efficient use of bandwidth and helps signal propagation over long distances.

6

Is a wireless site survey worth it?

Reference answer

Yes, a wireless site survey is very valuable and is viewed as an essential step for organizations planning to install or upgrade a wireless network. Here's why: Optimal network design Nile uses site surveys to ensure the network is designed effectively from the start, considering factors such as signal strength, capacity, coverage, and the locations of access points. This foundational work is critical in establishing a robust and reliable Wi-Fi network. Cost savings Poorly deployed networks often lead to weak signals or dead zones, causing organizations to purchase more access points and cabling installation than necessary – something that can be avoided with Nile's initial site survey. By optimizing the network layout, organizations can avoid unnecessary issues and time lost. Increased productivity The reliability offered by Nile's site survey reduces downtime and increases productivity, as the IT staff and users won't be hindered by poor connectivity and subsequent help desk tickets. This directly translates to smoother operations and improved efficiency. Enhanced user experience A site survey can guarantee the best possible wireless experience for visitors and staff alike. Nile strives to ensure strong and consistent Wi-Fi coverage across each site to enhance user satisfaction and engagement. Futureproofing Nile's site surveys can even help in anticipating future requirements and growth, ensuring that the network can be scaled effectively when necessary. This forward-thinking approach is crucial for long-term success. Security assurance A site survey can highlight potential vulnerabilities in a network's security, allowing them to be addressed before the network becomes operational. This is especially important in urban or dense areas where neighboring Wi-Fi deployments may cause issues. This proactive measure is vital in Nile's planning process as safeguarding the network against potential threats. However, it's also worth noting that the value of a wireless site survey will highly depend on the size of the premises, the number of users, and how critical wireless connectivity is to business operations. In smaller environments with less demand, for example, a wireless site survey might not be necessary.

7

Discuss the impact of the Internet of Things (IoT) on wireless protocol development and RF engineering.

Reference answer

The candidate should exhibit comprehension of the unique challenges IoT presents, including the need for low power, wide coverage, and scalability, and how these influence protocol design.

8

Describe the 802.11 Association process

Reference answer

Explain the frame exchange between the endpoint/client and the Access Point before the client goes into ‘RUN' state and is authenticated and is able to pass traffic. Provide as much detail as possible. There can be spin off questions based on your response to this question. The answer is probe request, probe response, 802.11 open authentication request, auth response (success), client sends association/ reassociation request and AP responds to that with a association/reassociation response (success). After this depending on the security type of the WLAN/SSID, further frames are exchanged. in the below snippet of wireshark you can see the reassociation process followed by EAP/TLS handshake

9

Which devices can interfere with wireless network operation?

Reference answer

Interfering Devices: Microwave ovens, cordless phones.

10

What is the difference between a "level" and a "theodolite"?

Reference answer

- Level: Primarily used for measuring differences in elevation. It provides a horizontal line of sight, and measurements are taken with a leveling staff. - Advantages: Highly accurate for determining elevations, simpler to operate. - Disadvantages: Limited to elevation measurements, not suitable for measuring angles. - Theodolite: Measures horizontal and vertical angles with high precision. It can be used for both horizontal and vertical control surveys. - Advantages: Versatile for both angle and distance measurements, suitable for a wide range of surveying tasks. - Disadvantages: More complex to operate than a level, typically requires manual distance measurements (except in total stations).

11

How does Wi-Fi 7 enhance latency performance?

Reference answer

Wi-Fi 7 enhances latency performance through features like Multi-Link Operation (MLO) and Target Wake Time (TWT) enhancements. MLO reduces latency by allowing data to be transmitted over multiple links simultaneously, minimizing delays caused by network congestion. TWT enhancements optimize power-saving mechanisms, reducing the time devices spend in a low-power state and improving response times.

12

Describe the process in detail on how wifi client gets on the wifi network and starts passing traffic

Reference answer

Pretty much the same answer as question 1.

13

What validation data points can you only get onsite during a Wi-Fi site survey?

Reference answer

Validation data points only available onsite include: verified floor plan accuracy (validating distances and wall locations), wall types and expected signal attenuation (using devices like the Ekahau Sidekick 2 for exact RF measurements), access to predictive design AP locations (checking for obstacles like HVAC ducting), and noisy neighbors (observing the spectrum and capturing channel energy to optimize network channels).

14

What is the importance of surveying in construction?

Reference answer

Surveying plays a crucial role in construction projects: - Site Layout and Setting Out: Surveys establish the boundaries and determine the exact location for foundations, buildings, and other structures. - Leveling and Grading: Leveling surveys ensure proper drainage and establish the correct slope for foundations and roads. - Volume Calculation: Surveys determine the amount of materials required for excavations, fills, and concrete pours. - Progress Monitoring: Surveys track the construction progress and ensure adherence to design specifications. - As-built Surveys: Final surveys are conducted to document the actual completed construction, which is essential for recordkeeping and future maintenance.

15

Discuss the role and importance of filter design in the development of RF circuits. What types of filters are commonly used?

Reference answer

The candidate should demonstrate in-depth knowledge of filter types (low-pass, high-pass, band-pass, band-stop) and their significance in RF applications, such as signal integrity and interference mitigation.

16

How does a wireless controller manage multiple access points?

Reference answer

A wireless controller centralizes the management of multiple access points, allowing for streamlined configuration, monitoring, and optimization. It handles tasks such as firmware updates, channel planning, load balancing, and security enforcement.

17

How do you stay updated with the latest trends and technologies in wireless networking?

Reference answer

“I regularly attend industry conferences like Mobile World Congress and participate in webinars from organizations like IEEE. I also encourage my team to engage in knowledge-sharing sessions, where we discuss recent advancements and their potential impact. Recently, we adopted a new network slicing technology that improved our service delivery for different customer segments. I believe staying informed is essential not just for personal growth but also for driving innovation within the team.”

18

What is LTE Advanced Pro?

Reference answer

LTE Advanced Pro (also known as LTE-A Pro) is an enhancement of LTE that introduces new features like higher-order carrier aggregation, massive MIMO, and advanced modulation techniques. It provides faster data rates and better performance compared to standard LTE.

19

Where should the equipment be placed to ensure the most optimal performance?

Reference answer

A wireless site survey can identify where equipment should be placed to ensure the most optimal performance.

20

What tools are used for securing wireless networks?

Reference answer

Tools for securing wireless networks include using strong encryption protocols like WPA2 or WPA3, implementing firewalls, disabling SSID broadcasting, enabling MAC address filtering, and using VPNs. Additionally, monitoring tools like Wireshark can help detect unauthorized access or vulnerabilities.

21

How do you distinguish between hardware and software issues when faced with an RF system malfunction?

Reference answer

Candidates should demonstrate their capability to differentiate hardware faults from software configuration errors and articulate the approaches for troubleshooting both.

22

When designing RF systems, how do you approach compliance with international regulations, and what challenges have you faced in this area?

Reference answer

Expectations here include the ability to design systems that meet diverse international standards and manage the complexities involved. The candidate should share specific challenges and solutions from their past experience.

23

Describe a time you ran into a problem when you were in the field you didn't know how to solve right away, and how did you address it?

Reference answer

The candidate should explain a specific situation where they encountered an unfamiliar problem, the steps they took to analyze and resolve it, and the outcome.

24

If a team member is struggling with a new wireless technology, how would you assist in their training?

Reference answer

I would schedule weekly sessions to identify the areas they are struggling with and provide focused resources. Encouraging hands-on practice through labs would also help them gain confidence.

25

What are the data rates of 802.11b, 802.11g, 802.11a, 11n and 11ac (they can also ask history of 802.11b, g and a). There are too many 802.11n MCS rates so most likely you should not expect a question like that.

Reference answer

802.11n rates: http://mcsindex.com/ 802.11ac MCS rates

26

What is the difference between Active scanning and Passive scanning?

Reference answer

Passive scanning: Its the process where the client (STA) listens (on different channels) to the beacons from the AP or Ad Hoc station. The STA continues to listen to the beacons till its hears a beacon with the SSID of the network it wishes to join. Active scanning: This involves the STA sending a probe request frame. The station sends the probe request frame when it is actively trying to join a specific SSID (network). The probe request frame will either contain the SSID name of the network or a broadcast SSID. If probe request is sent specifying a specific SSID, then only the APs serving the SSID will respond with a probe response frame. If probe request is sent with broadcast SSID then all APs within reach will respond.

27

How do you handle working with clients?

Reference answer

I have experience working with clients, including experience communicating project requirements, discussing project progress, and addressing any concerns or questions. I am able to understand client needs and provide solutions that meet their requirements. I also have experience in preparing and delivering presentations to clients and stakeholders.

28

Is there any way to recover my password for WLC?

Reference answer

Password Recovery: Use the CLI and Restore-Password command for versions 5.1 and later; otherwise, reset to factory defaults.

29

What is IBSS and BSS?

Reference answer

IBSS (Independent Basic Service Set): Direct device-to-device communication without a central device. BSS (Basic Service Set): Wireless LAN established using an Access Point.

30

When 2 laptops wirelessly connected can communicate directly, what type of topology is created?

Reference answer

Full Mesh Topology (Ad-hoc Network): Each node is directly connected to all other nodes.

31

What is Wi-Fi and what is WiMAX?

Reference answer

- Wi-Fi: Wireless Fidelity, a technology that uses radio waves for high-speed network connectivity based on IEEE 802.11 standards. Devices include PCs, laptops, video game consoles, phones, tablets, smart TVs, and more. - WiMAX: Worldwide Interoperability for Microwave Access, referenced by IEEE 802.16, commonly termed 4G. It provides wide area network access and uses OFDM modulation.

32

What should you consider when identifying needs for a Wi-Fi site survey?

Reference answer

You need to identify your network requirements, including what sort of speed and bandwidth will be required, and how many human resources and workstations you are expecting to support.

33

How do we prevent loops on the WLC?

Reference answer

- STP (Spanning Tree Protocol): Enabled to prevent network loops.

34

What are the different types of coordinate systems used in surveying?

Reference answer

Common coordinate systems used in surveying include: - Geographic Coordinate System (GCS): Uses latitude and longitude to define positions on the Earth's surface. Examples include the World Geodetic System 1984 (WGS84) and the North American Datum of 1983 (NAD83). - Projected Coordinate System (PCS): Transforms the curved Earth's surface onto a flat plane using mathematical projections. Examples include the Universal Transverse Mercator (UTM) and the State Plane Coordinate System (SPCS). - Local Coordinate System (LCS): Created for specific projects and uses local reference points and units. It is typically used for small areas where accuracy is critical.

35

Models of Outdoor Rugged Access Points/Bridges?

Reference answer

- Models Include: Aironet 1530, 1540, 1560, 1570, 1552, and Industrial Wireless 3702. Below are some of the latest Cisco Outdoor Rugged Access Points - Aironet 1530 Series Aironet 1540 Series Aironet 1560 Series Aironet 1570 Series Aironet 1552 Access Point Industrial Wireless 3702

36

Explain how intermodulation distortion can affect RF signal analysis and how you can minimize its impact.

Reference answer

Expecting candidates to have an in-depth knowledge of non-linear effects like intermodulation distortion in RF systems and to discuss methods to reduce its impact, such as through careful system design or signal processing.

37

What is SSID, and why is it important in wireless networks?

Reference answer

SSID (Service Set Identifier) is the name assigned to a wireless network. It allows wireless devices to identify and connect to the correct network among multiple networks in the vicinity. The SSID is essential for network segmentation and user access.

38

Explain the concept of "datum" in surveying.

Reference answer

A datum is a reference surface or point used as the basis for measuring elevations, distances, and other surveying data. It provides a common reference frame for all measurements within a specific area. For example, the North American Vertical Datum of 1988 (NAVD88) serves as the standard datum for elevation measurements in North America.

39

What factors influence bandwidth allocation in a wireless network? How do you manage bandwidth effectively?

Reference answer

Bandwidth allocation is influenced by factors like user demand and network congestion. I prioritize critical applications using QoS policies and monitor traffic with tools to dynamically adjust allocations as needed.

40

What experience do you have with designing wireless mesh networks?

Reference answer

The candidate should describe their involvement in mesh network design, including topology, routing protocols, and deployment considerations.

41

Describe the purpose of a captive portal in wireless networking.

Reference answer

A captive portal is a web page that users are redirected to when connecting to a public or guest wireless network. It typically requires users to authenticate or accept terms of service before granting access to the internet or network resources.

42

Can you describe a time when you identified a non-compliance issue related to RF engineering? How did you address it?

Reference answer

The candidate should demonstrate their ability to recognize non-compliance issues and how they proactively resolved the situation. This assesses their practical knowledge and experience in regulatory compliance within RF engineering.

43

What is ESS?

Reference answer

- ESS (Extended Service Set): Created by connecting multiple BSSs via a distribution system, allowing larger coverage and seamless client roaming.

44

Canyou describe your experience with radio networks, including antenna systems designs and analysis?

Reference answer

This will provide an understanding of the candidate's skills and experience with designing and analyzing radio networks and antenna systems, which are vital for executing wireless services.

45

How do you work to improve the performance and capacity of Wireless Fidelity?

Reference answer

Wireless Fidelity (Wi-Fi) performance and capacity directly influence user experience. The candidate's answer will give an insight into their capacity to optimize Wi-Fi networks and ensure a positive user experience.

46

Can you explain the differences between the various 802.11 standards in the context of RF engineering?

Reference answer

Candidates should show an understanding of how each 802.11 standard differs in frequency, bandwidth, data rate, and range, and the impacts on RF design and deployment.

47

How do you keep your skills and knowledge current in the rapidly evolving field of wireless technology?

Reference answer

“I regularly read industry publications like 'Wireless Week' and attend the IEEE Wireless Communications conferences. I'm also a member of the Wi-Fi Alliance, which helps me engage with peers and learn about emerging standards. Recently, I completed a certification in 5G technology, which I have started implementing in our project planning discussions to ensure we remain ahead of the curve.”

48

How would you approach the design and optimization of an antenna system for a specific wireless protocol?

Reference answer

Candidate should discuss factors such as gain, bandwidth, polarization, and radiation patterns, and how these affect the performance of wireless protocols like Wi-Fi, Bluetooth, or LTE.

49

Do I Need A WiFi Survey For An Existing Network?

Reference answer

Yes. A WiFi survey can be just as useful for an existing network as it is for a new one. It helps uncover the causes of slow performance, dead zones, dropped connections, and inconsistent coverage, while also guiding improvements to access point placement and configuration.

50

When should active site surveys be performed?

Reference answer

Teams should perform active surveys when investigating performance problems.

51

What equipment is needed for a professional Wi-Fi site survey?

Reference answer

Professional wireless site surveys utilize specialized equipment, including: • Spectrum analyzers to detect rogue devices across all Wi-Fi bands • Site survey software that creates detailed heat maps and performance visualizations • Specialized wireless adapters that support all current standards • Calibrated measurement tools for precise signal analysis

52

Can you give an example of how you've had to adapt to new wireless technologies or changes in standards? What was the impact?

Reference answer

In my previous role, I adapted to the introduction of 802.11ax (Wi-Fi 6) by taking online courses to understand its features. I then led a project to upgrade our existing network, which improved performance by 30%.

53

What is a predictive site survey?

Reference answer

Predictive site surveys use software to predict the optimal location for access points based on known information about RF interference.

54

What is the frequency range of the 802.11a standard?

Reference answer

- 5GHz Frequency.

55

What are the three types of wireless site surveys?

Reference answer

The three types of wireless site surveys are predictive surveys, passive surveys, and active surveys. Predictive surveys are performed before moving into a new space. Passive surveys collect information about all the signals in the environment after the site is built. Active surveys focus on a specific signal or set of signals while the network is in full operation.

56

Is additional equipment necessary, such as an access point or antenna?

Reference answer

A wireless site survey can determine if additional equipment, such as an access point or antenna, is necessary.

57

What is an AP on a Stick site survey?

Reference answer

The data collection is like a Passive Survey but now the tech is using the customer's desired future state APs & Antennas. This is like having a sneak peek into the future deployment of your wireless infrastructure.

58

Discuss a time when you had to troubleshoot a complex signal integrity issue.

Reference answer

Candidates should share a relevant experience where they applied their signal analysis skills to resolve an issue, highlighting their analytical process and problem-solving capabilities.

59

What is the difference between FDD and TDD?

Reference answer

Frequency Division Duplex (FDD): Uses separate frequencies for uplink and downlink communication. Time Division Duplex (TDD): Uses the same frequency for both uplink and downlink but separates them by time intervals.

60

What are the steps to conduct a wireless site survey?

Reference answer

The steps are: 1. Set clear objectives by defining what you want to achieve with your wireless network. 2. Collect site information by gathering up-to-date floor plans and noting construction materials and large objects. 3. Select appropriate tools like WiFi scanners, spectrum analyzers, and specialized software. 4. Conduct a passive survey by walking through the site during normal operating hours. 5. Perform an active survey by connecting to your WiFi network and measuring real-time performance metrics. 6. Interpret the data using survey software to create heatmaps and reports. 7. Develop recommendations such as repositioning or adding access points and changing channel assignments. 8. Implement changes and validate with a follow-up survey.

61

What tools do you typically use for diagnosing wireless network issues? Can you describe a situation where you used them effectively?

Reference answer

I typically use Wireshark for packet analysis and Ekahau for site surveys. In a previous role, I identified overlapping channels causing poor connectivity with Ekahau, then adjusted the access point configuration to optimize performance, resulting in a 30% improvement in user satisfaction.

62

What is a wireless site survey?

Reference answer

In the world of networking, wireless site surveys are nothing more than a process designed to ensure that a wireless network will provide optimal coverage and support the best possible performance. It can help you determine things like how many access points are needed, where they should be located, and spot areas of potential interference. But most importantly, it provides a current view of how your wireless infrastructure is performing.

63

What is a predictive site survey?

Reference answer

A predictive site survey, also known as a predictive WiFi design, uses advanced software from companies like Ekahau, to model your environment and create different types of WiFi heat maps. It establishes what's required to deploy a high performing WLAN system and approximately how much it will cost.

64

Explain the difference between a "ground survey" and an "aerial survey".

Reference answer

- Ground Survey: Involves measurements taken directly from the ground using traditional surveying instruments. - Advantages: More precise for detailed measurements, suitable for small areas. - Disadvantages: Time-consuming and labor-intensive, can be challenging in difficult terrain. - Aerial Survey: Uses aircraft or drones to capture images and data from the air. - Advantages: Efficient for large areas, provides a wider perspective, can access inaccessible terrain. - Disadvantages: Less precise than ground surveys, requires specialized equipment and expertise.

65

How do you calculate signal-to-noise ratio, and why is it important in wireless communications?

Reference answer

Signal-to-noise ratio, or SNR, measures the level of a desired signal compared to background noise. It is calculated using the formula SNR = power of the signal divided by power of the noise. A higher SNR indicates better quality and reliability of communication, which is critical for maintaining clear connections and maximizing data throughput.

66

What is a predictive wireless survey?

Reference answer

A predictive site survey is based on layouts and drawings of the location or building. This information is then fed into a predictive survey software which then provides estimates based on the information provided. This is a more cost-effective option if you are looking for a quick turnaround for estimated pricing for a wifi installation but won't be as accurate as an on-location survey.

67

Explain the concept of channel fading.

Reference answer

Channel fading refers to the variation in the strength of the received signal due to factors like multipath propagation, interference, and movement of the transmitter or receiver. Fading affects the reliability of the communication link.

68

Major differences between Cisco 2500 Series and 5500 Wireless Controllers?

Reference answer

- Cisco 2500 vs 5500: 5500 supports more APs and clients, offers higher throughput, and advanced features compared to 2500.

69

How do you stay current with emerging wireless technologies and standards?

Reference answer

“I regularly read publications like IEEE Wireless Communications and attend industry conferences such as Mobile World Congress. I recently completed a certification in Wi-Fi 6 technologies, which I've already started applying by upgrading our existing networks. Additionally, I'm part of a local networking group where we discuss the latest trends and solutions.”

70

What is the educational requirement to become a Freelance Site Survey Specialist?

Reference answer

There are no specific educational requirements to become a Freelance Site Survey Specialist, but a minimum of a degree in Telecommunication engineering and related field along with experience is required.

71

You are tasked with troubleshooting a drop in the RF signal strength in a wireless communication system. How would you approach this problem systematically?

Reference answer

The candidate should describe a step-by-step method for diagnosing and resolving signal strength issues, showing an understanding of RF systems and the ability to troubleshoot methodically.

72

What is a "station" in surveying?

Reference answer

In surveying, a station refers to a specific point on the ground that has been established and marked. Stations serve as reference points for taking measurements and defining the location of other points within a survey. They are typically numbered sequentially for easy identification and referencing in field notes and calculations.

73

What is Fast Roaming?

Reference answer

Fast Roaming: Device handshakes with a new AP before roaming to ensure seamless transition and avoid re-authentication.

74

In terms of RF engineering, how do you evaluate the performance of a wireless protocol in a new product development cycle?

Reference answer

Candidates should describe methods such as simulation, prototyping, and field testing, along with relevant performance metrics such as signal strength, SNR, and data rates.

75

What is a topographic survey?

Reference answer

A topographic survey involves determining the elevation, shape, and features of a specific area. It uses leveling techniques, GPS, or aerial imagery to create detailed topographic maps or models. Topographic surveys are crucial for: - Land Development: Planning and designing residential, commercial, or industrial developments. - Infrastructure Projects: Designing and constructing roads, bridges, and other infrastructure. - Environmental Studies: Analyzing terrain, water flow, and other environmental factors. - Military Operations: Creating accurate terrain maps for planning and executing military operations.

76

What parameters would you consider when performing link budget analysis for a wireless communication system?

Reference answer

The candidate should enumerate critical parameters such as path loss, antenna gain, transmit power, and receiver sensitivity, underscoring their understanding of the complexity and interplay of factors in RF link budget analysis.

77

What are the different types of wireless propagation?

Reference answer

The three main types of propagation are: Line-of-Sight (LOS): Signals travel directly from the transmitter to the receiver with no obstacles. Non-Line-of-Sight (NLOS): Signals are obstructed by obstacles and rely on reflections, diffraction, or scattering. Groundwave/Surface wave: Signals propagate close to the earth's surface.

78

With 5G technology rapidly advancing, how does this affect existing wireless protocols and RF engineering considerations?

Reference answer

The candidate is expected to provide insight into the integration and coexistence of 5G with legacy protocols, the adjustments needed in RF design, and the overall evolution of wireless communication systems.

79

What are the potential challenges in deploying Wi-Fi 7 networks?

Reference answer

Potential challenges in deploying Wi-Fi 7 networks include the need for compatible hardware, such as routers and client devices that support the new standard. The adoption of features like 320 MHz channels and 4096-QAM may also be limited by regulatory restrictions and the quality of the wireless environment. Additionally, the complexity of managing multiple links and ensuring seamless Multi-Link Operation (MLO) might require advanced network management tools and expertise.

80

Do you understand wireless carrier standards and protocols, and what experience do you have working with them?

Reference answer

Awareness about carrier standards and protocols ensures that the candidate is well-equipped to interact with various wireless carriers and their respective infrastructure. Their answer will reflect their practical knowledge and expertise in working with different wireless carriers.

81

What role does Wi-Fi 7 play in supporting 8K video streaming and virtual reality (VR)?

Reference answer

Wi-Fi 7's higher data rates, wider channels (up to 320 MHz), and lower latency make it ideal for demanding applications like 8K video streaming and VR. The increased capacity and reduced latency ensure smooth, uninterrupted streaming and immersive VR experiences, even in environments with multiple devices connected to the network.

82

What is the difference between Wi-Fi 5 (802.11ac) and Wi-Fi 6 (802.11ax)?

Reference answer

Wi-Fi 5 (802.11ac): Operates on the 5 GHz band and offers high-speed wireless connectivity with wider channels and MIMO. Wi-Fi 6 (802.11ax): Enhances Wi-Fi 5 by providing faster speeds, lower latency, and better performance in dense environments through technologies like OFDMA and MU-MIMO.

83

What equipment is required?

Reference answer

A wireless site survey can answer what equipment is required for optimal WLAN performance.

84

Explain the differences between time-domain and frequency-domain analysis in RF signal processing. When would you use each method?

Reference answer

Expect an in-depth explanation of the two domains, their significance, and appropriate contexts to apply each for efficient signal analysis.

85

Can you explain a time when you had to handle a budgetary constraint for an RF Engineering project? How did you manage to deliver the project within the financial limitations?

Reference answer

Seeking insight into the candidate's financial acumen, prioritization, and negotiation skills. Expect examples of trade-off decisions and strategic resource allocation.

86

What is leveling in surveying?

Reference answer

Leveling is the process of determining the elevation or height difference between two or more points on the Earth's surface. This is done by using a level instrument to create a horizontal line of sight and measuring the vertical distance from that line to the points being surveyed.

87

What are the different types of surveying instruments?

Reference answer

Common surveying instruments include: - Total Station: Combines an electronic theodolite and distance meter for precise angle and distance measurements. - Level: Measures differences in elevation by providing a horizontal line of sight. - Theodolite: Measures horizontal and vertical angles with high accuracy. - Tape Measure: Used for measuring distances manually. - GPS Receiver: Uses satellites to determine precise coordinates. - Drone: Provides aerial photography and data for creating maps and models.

88

What are some ethical considerations for surveyors?

Reference answer

Surveyors are bound by ethical codes of conduct that emphasize: - Accuracy and Integrity: Providing accurate and reliable survey data, maintaining high standards of professionalism. - Confidentiality: Protecting the confidentiality of client information and survey data. - Objectivity: Conducting surveys and providing reports with objectivity and impartiality, avoiding conflicts of interest. - Public Safety: Prioritizing public safety and ensuring the accuracy of surveys that impact infrastructure or public works. - Professional Development: Continuously improving their skills and knowledge through ongoing education and training.

89

Describe a challenging situation you faced while designing or testing a wireless protocol and how you resolved it.

Reference answer

The candidate is expected to demonstrate problem-solving skills and practical knowledge in dealing with real-world RF engineering issues related to wireless protocols.

90

What are the main factors affecting Wireless Network?

Reference answer

Factors Include: Distance, obstructions, wireless standard, signal sharing, and network interference.

91

What is the frequency range of the 802.11a standard?

Reference answer

5GHz Frequency.

92

What steps would you take if you notice unexpectedly high data traffic in a wireless network?

Reference answer

First, I would use monitoring tools to identify the traffic sources and patterns. Then, I'd check for any unknown devices connected to the network. If anything looks suspicious, I'd analyze the data types to find any anomalies, and finally, I'd implement security measures to prevent potential breaches.

93

What is the function of WLAN on WLC?

Reference answer

- WLAN: Similar to SSID, required for client association with the network.

94

Can you walk me through the process of analyzing and resolving VSWR (Voltage Standing Wave Ratio) problems in an RF system?

Reference answer

The candidate should clearly explain the steps taken to measure, analyze, and correct VSWR issues. It reveals their hands-on experience and understanding of RF principles.

95

What is Piggybacking in the context of Wi-Fi?

Reference answer

Piggybacking: Unauthorized use of someone else's wireless connection without their permission.

96

What are the different types of surveying software?

Reference answer

Surveying software helps manage and analyze survey data, automate calculations, and generate reports. Some popular software options include: - AutoCAD Civil 3D: A comprehensive software for design, analysis, and documentation of civil engineering projects, including surveying. - Bentley MicroStation: Another powerful software for surveying and other civil engineering tasks, known for its capabilities in handling large-scale projects. - Trimble Business Center: A software suite for data processing, analysis, and visualization, supporting a wide range of surveying instruments. - Terramodel: Specialized software for terrain modeling, surface analysis, and volumetric calculations. - Cloud-based Software: Platforms like Autodesk BIM 360 and Trimble Connect enable online collaboration, data sharing, and project management in surveying.

97

What is the goal of a passive site survey?

Reference answer

The goal of a passive survey is to report on all signals at each location, including the installed network and signals from neighboring sites or other devices that generate noise at wireless frequencies.

98

What is the function of WLAN on WLC?

Reference answer

WLAN: Similar to SSID, required for client association with the network.

99

How do you configure a Wi-Fi network?

Reference answer

Configuring a Wi-Fi network involves setting up a wireless access point or router, selecting a network name (SSID), choosing a security protocol such as WPA2 or WPA3, setting a strong password, and configuring network settings like DHCP and IP addressing. The process may vary depending on the device and interface used.

100

What is the goal of a predictive site survey?

Reference answer

The goal of a predictive site survey is to determine where to place APs for the best performance throughout the area. Network teams should perform a predictive survey before moving any equipment or furniture into a new space.

101

What is the frequency range of the 802.11g standard?

Reference answer

- 2.4GHz Frequency.

102

What is interference in wireless communication?

Reference answer

Interference is the unwanted disruption of a signal by other signals, which can degrade communication quality. It can be caused by overlapping frequency channels, other wireless devices, or environmental factors.

103

Describe a complex wireless network design project you led and the challenges you faced.

Reference answer

“At Singtel, I led the design of a large-scale Wi-Fi solution for a major shopping mall. The primary challenge was to ensure seamless connectivity in areas with heavy interference. I collaborated with the engineering team to conduct a site survey, using predictive modeling to optimize access point placement. As a result, we achieved a 99.9% uptime and enhanced user experience, leading to a 30% increase in customer satisfaction scores.”

104

How many MCS rates are there for 802.11ac?

Reference answer

There are nine for a specific Spacial stream. http://wirelessonthego.postach.io/post/802-11ac-mcs-rates

105

What is the purpose of common survey tools in a wireless site survey?

Reference answer

Common survey tools help map predicted coverage and place access points.

106

What are the basic components of a wireless communication system?

Reference answer

The basic components include: Transmitter: Converts information into a signal for transmission. Receiver: Decodes the transmitted signal back into information. Channel: The medium (air, space) through which the signal propagates. Antenna: Facilitates the transmission and reception of signals.

107

What is MIMO, and why is it used in wireless systems?

Reference answer

Multiple Input Multiple Output (MIMO) is a technology that uses multiple antennas at both the transmitter and receiver to improve communication performance. It enhances data rates, increases capacity, and improves signal quality by using spatial multiplexing and diversity.

108

How long does a wifi site survey take?

Reference answer

The larger the building, the longer a survey will take. As a rule of thumb, a building or office with 2 floors and 5-8 rooms will take around 4 hours. For a larger warehouse or hotel – this can take a full day of around 6-8 hours.

109

What is a Wi-Fi site survey?

Reference answer

A Wi-Fi site survey is the process of collecting real-world RF (radio frequency) data across a space to understand how a wireless network actually performs in practice. It is used to validate predictive designs, verify deployments, and ensure reliable performance over time.

110

What is the difference between a "direct" and an "indirect" measurement in surveying?

Reference answer

- Direct Measurement: Directly measures the quantity of interest using appropriate instruments. Examples include measuring distances with a tape measure or angles with a theodolite. - Advantages: More accurate for shorter distances and simpler measurements. - Disadvantages: Not practical for long distances or complex measurements. - Indirect Measurement: Determines the quantity of interest indirectly by measuring other related quantities and using mathematical calculations. Examples include calculating distances using trigonometry or determining elevations using leveling techniques. - Advantages: Suitable for long distances or complex measurements, can be more efficient. - Disadvantages: Less accurate than direct measurements, requires additional calculations.

111

Which encryption type does WPA2 use?

Reference answer

WPA2 uses AES: A newer Wi-Fi encryption solution that is more secure than the older TKIP used in WPA.

112

What is handover in cellular networks?

Reference answer

Handover is the process of transferring an ongoing call or data session from one cell to another as the user moves. It ensures seamless communication without dropping connections as users move through different coverage areas.

113

Describe the role of modulation and demodulation in RF signal processing and how errors might be introduced in these processes.

Reference answer

Candidates should convey their knowledge of modulation techniques, the purposes they serve, and the common errors or issues that can arise, demonstrating deep knowledge of RF systems.

114

How can a fresher prepare for a career in surveying?

Reference answer

Freshers can prepare for a surveying career by: - Pursuing Relevant Education: Enroll in a bachelor's degree program in surveying, geomatics, or a related field. - Gaining Practical Experience: Seek internships or part-time jobs in surveying firms to gain hands-on experience. - Developing Technical Skills: Learn to use surveying instruments, software, and techniques through courses or self-study. - Networking: Attend industry events, join professional organizations, and connect with experienced surveyors. - Staying Updated: Keep up with the latest advancements and trends in surveying technology and methodology. - Building Soft Skills: Develop communication, teamwork, and problem-solving skills to enhance professionalism.

115

How would you evaluate the potential integration of a new wireless technology into an existing infrastructure?

Reference answer

I would start by checking if the new technology works with our existing systems and identify any required upgrades. Then, I'd analyze performance data to see how it could enhance our service. I'd also look into costs and any risks involved in the transition.

116

Changes in WLAN-11ac compared to previous versions?

Reference answer

802.11ac Enhancements: Includes Multi-User MIMO, wider RF channels, and more spatial streams for faster and more efficient network performance. There are 2 variants of 802.11ac — phase 1 and phase 2. 802.11ac is faster compared to previous standards because of the introduction of the below Multi-User MIMO (MU-MIMO) — Clients get on and off the network quicker, allowing more clients to be served, Pre Wave 2 an access point would talk to the clients one at a time and this was called SU-MIMO. Multi-user MIMO is important because it allows access points and their many antennas to transmit (or talk) to multiple client devices all at the same time. This helps maximize air-time efficiency so that each client, regardless of what version of 802.11 it is running, gets the amount of airtime it's supposed to get based on the technology supported. Wider RF Channels — Wave 2 improvement is the option to use 160-MHz channel widths. That's double what we saw with Wave 1 technology. Think of this as a 2 line interstate road where two additional lines have been added. The top speeds depend on the whether the AP supports 80-MHz or 160-MHz channels, as well as whether the wireless client devices tapping your network support Wave 2. Four Spatial Streams — Wave 2 also supports four transmitting and receiving antennas while the previous iteration supported only three receive antennas. Just like we see in the image below, With 4 spatial streams an AP could send 4 streams of data to the same client at the same time. The client can then aggregate this 4 streams and thus improve its throughput. It is also important to notice that on the AP side, the greater the number of receive antennas, the greater the distance that a particular data rate can be sustained.

117

Describe a scenario in which you had to adjust your project management approach due to unforeseen circumstances in an RF Engineering context. How did you handle it?

Reference answer

Look for flexibility and problem-solving skills—key components in project management. The candidate should be able to provide a clear example of adaptability and decision-making under pressure.

118

What are the key differences between Zigbee and Bluetooth?

Reference answer

Zigbee: Focuses on low-power, low-data-rate communication and is mainly used for industrial and home automation. Bluetooth: Designed for short-range, high-data-rate communication, used for wireless audio, peripherals, and personal area networks.

119

Major differences between Cisco 2500 Series and 5500 Wireless Controllers?

Reference answer

Cisco 2500 vs 5500: 5500 supports more APs and clients, offers higher throughput, and advanced features compared to 2500.

120

How does a wireless mesh network work?

Reference answer

A wireless mesh network consists of multiple access points that communicate with each other to form a self-healing, redundant network. Each AP acts as a node that relays data, extending coverage and improving network resilience.

121

Can you describe your work experience with IoT (Internet of Things) and its wireless applications?

Reference answer

IoT has revolutionised various sectors, especially with wireless applications. Their experience in IoT could potentially enhance your business operations and drive productivity.

122

Have you led a team of engineers before?

Reference answer

The candidate should discuss any leadership experience, including team size, responsibilities, and outcomes of their leadership.

123

Can you explain the significance of phase noise in an RF system and how it can be mitigated?

Reference answer

Seeking detailed understanding of phase noise, its sources, its impact on system performance, and common strategies employed to reduce phase noise in RF systems.

124

What EAP method do you prefer and why?

Reference answer

The candidate should state a preferred EAP method, such as EAP-TLS for its strong security, and explain the reasoning based on deployment needs.

125

When should a WiFi site survey be used?

Reference answer

This type of service is perfect for planning new WiFi deployments or network refreshes in more complex environments. Complexity usually encompasses high-density environments, applications that roam from AP to AP and apps that tend to be latency-sensitive. For example, RTLS in hospitals, wireless video surveillance, and multi-media over wireless.

126

What are the main factors affecting Wireless Network?

Reference answer

- Factors Include: Distance, obstructions, wireless standard, signal sharing, and network interference.

127

What is 802.1x?

Reference answer

- 802.1x: IEEE standard for port-based network access control, providing an authentication framework for wireless LANs. It authenticates devices wishing to attach to a LAN or WLAN through a central authority.

128

What is the role of a wireless controller in a network?

Reference answer

A wireless controller manages and configures multiple wireless access points from a central location. It provides centralized management, monitoring, and optimization of wireless networks, including features like roaming, load balancing, and security.

129

What is the difference between WPA2 and WPA3 security protocols?

Reference answer

WPA2 uses AES (Advanced Encryption Standard) for encryption and provides strong security for wireless networks. WPA3 improves on WPA2 by offering enhanced protection against brute-force attacks, improved encryption, and more robust authentication methods.

130

What is the role of a wireless network gateway?

Reference answer

A wireless network gateway serves as the interface between the wireless network and external networks (e.g., the internet). It manages traffic, provides security features like NAT (Network Address Translation), and may include firewall capabilities.

131

What are the different modes of a Cisco Access Point (AP) operation?

Reference answer

- Modes Include: Local, REAP, Monitor, Rogue Detector, Sniffer.

132

What is the significance of the Nyquist theorem in wireless communication?

Reference answer

The Nyquist theorem states that the maximum data rate for a noiseless channel is twice the bandwidth of the channel. It helps determine the minimum sampling rate required to avoid aliasing in digital communication systems.

133

What is a "benchmark" in surveying?

Reference answer

A benchmark is a permanently established point with a known elevation or coordinate. It serves as a reference point for leveling and other surveying measurements. Benchmarks are typically marked with a brass or concrete marker and are used to ensure consistency and accuracy in elevation measurements over time.

134

What is the data rate of the 802.11a standard?

Reference answer

Up to 54Mbps.

135

What is Multi-AP Coordination, and how does it benefit Wi-Fi 7 networks?

Reference answer

Multi-AP Coordination is a feature in Wi-Fi 7 that allows multiple access points (APs) within the same network to coordinate their transmissions. This reduces interference, optimizes channel usage, and enhances overall network performance, particularly in dense environments. It allows for more efficient use of available spectrum and improves the quality of service for connected devices.

136

Explain how you would design a wireless network for a large urban area. What factors would you consider?

Reference answer

I would start by analyzing the population density to determine user hotspots. Then, I'd review existing infrastructure such as buildings and parks that may affect signal propagation. By selecting the appropriate frequency bands, I can ensure optimal coverage and capacity. Finally, I would include plans for scalability to accommodate future users.

137

What is the significance of using channel width in wireless networks?

Reference answer

Channel width affects the data rate and bandwidth of a wireless network. Wider channels (e.g., 40 MHz, 80 MHz) provide higher throughput but can also increase interference. Properly selecting channel width helps balance performance and interference.

138

When should a predictive site survey be used?

Reference answer

A predictive site survey is perfect for most environments today. Even in high-density areas, we can produce optimal results when having the right software, amounts of information, and enough experience. Predictive site surveys are best when deploying WiFi for the first time at a given location or refreshing an existing network.

139

What are the different types of surveying?

Reference answer

Surveying can be broadly categorized into: - Plane Surveying: Deals with small areas where the Earth's curvature is negligible. Examples include: - **Cadastral Surveying:** Determining land boundaries for property ownership. - **Topographical Surveying:** Creating detailed maps showing elevation, contours, and features of a specific area. - **Construction Surveying:** Setting out construction projects and monitoring progress. - **Route Surveying:** Designing and surveying roads, railways, and pipelines. - Geodetic Surveying: Considers the Earth's curvature and deals with larger areas. Examples include: - **Control Surveys:** Establishing a network of reference points for accurate positioning within a region. - **Satellite Surveying (GPS):** Using satellites to determine precise positions on the Earth's surface.

140

What are the different types of errors in surveying?

Reference answer

Errors in surveying can be categorized into: - Instrumental Errors: Caused by imperfections or malfunctioning of the surveying instruments used. - Natural Errors: Resulting from atmospheric conditions, temperature variations, or refraction of light. - Personal Errors: Introduced due to human limitations and mistakes, such as incorrect readings or misinterpretations. - Accidental Errors: Random errors that occur due to unforeseen circumstances or chance variations.

141

What is the master controller mode on WLC?

Reference answer

- Master Controller Mode: Designates a controller as the tie-breaker when multiple controllers are available.

142

What is the role of a rogue AP detection system?

Reference answer

A rogue AP detection system identifies unauthorized or insecure access points that may be connected to the network. It helps prevent potential security breaches by alerting administrators to unauthorized devices that could compromise network integrity.

143

What is a control survey and why is it important?

Reference answer

A control survey establishes a network of accurately determined reference points (control points) with known coordinates. These control points provide a framework for all subsequent surveys within a region. Control surveys are essential for: - Accuracy and Consistency: Ensuring the accuracy and consistency of all subsequent surveys by providing a reliable reference. - Geodetic Control: Establishing a geodetic network that accounts for the Earth's curvature for large-scale projects. - Coordinate Reference: Providing a common reference frame for all surveyed points within the region. - Monitoring Deformation: Detecting and monitoring changes in the Earth's surface due to geological events or construction activities.

144

How would you troubleshoot a user's wireless connectivity issue?

Reference answer

“If a user reports connectivity issues, I would first check the access point's status and signal strength using a tool like Wireshark. Then, I would look for potential interference from nearby devices. If necessary, I would conduct a site survey to pinpoint dead zones. After identifying the issue, whether it's a weak signal or interference, I would adjust the access point's channel or position, and then verify the fix with the user.”

145

How would you use a vector network analyzer (VNA) in the assessment of RF components?

Reference answer

Candidates should describe the practical application of VNA in measuring factors like S-parameters, and impedance, and how those measurements assist in evaluating RF components for performance and reliability.

146

How would you troubleshoot one way audio issue

Reference answer

Typically one way audio issues stem from power mismatch between the AP and the VoWiFi device. The VoWiFI device has limited transmit power compared to the AP which can cause one way audio issues. The VoWiFi device can hear the AP communication even at relatively far off distances but at cell edge or beyond if the VoWiFi transmits data back, the AP sometimes cannot interpret the data leading to one way audio. This is the simplest form of one way audio issue. You need to determine if the communication is between 2 VoWiFi devices or one VoWiFi and one wired phone. There could be configurations that may block peer to peer communication which may potentially lead to one way audio or no audio between two VoWiFi devices. The way to troubleshoot such issue is normally double check the configurations are ok and adhere voice of wifi best practices and then delve into debugs + over the air captures for further isolating the problem.

147

What is the process of a wireless site survey?

Reference answer

The process of a wireless site survey involves several key steps to guarantee optimal Wi-Fi performance and network design: Understanding the organization's needs The first step in a wireless site survey is to comprehend the specific Wi-Fi requirements of the organization. This involves determining the number of devices to be supported, types of applications in use, and the expected traffic volume. This is a crucial step in Nile's Access Service implementation as it allows for the proposed network to align with the organization's current and future needs. Conducting an on-site physical inspection The next phase involves a thorough inspection of the site. Surveyors provided by Nile assess the layout to consider factors such as building materials, floor plans, and potential physical obstructions. This step also helps in identifying areas where Wi-Fi signals may be weak or obstructed. Identifying potential interference sources During the site inspection provided by Nile, it's important to identify potential sources of interference that could affect Wi-Fi connectivity and performance. These could include other wireless networks, electronic devices, or structural features that impede signal strength. Measuring signal strength and quality Surveyors use specialized tools to measure Wi-Fi signal strength and quality throughout the site. This step is vital in setting up a Nile Access Service as it ensures that the entire area receives adequate coverage. Analyzing data and planning the network The final step involves analyzing the data collected to construct the BoM and installation of the Nile Access Service. This includes determining the optimal placement of access points, ensuring comprehensive coverage, and planning for capacity to handle the anticipated workload. The result is a detailed network design that caters to the specific requirements of the site.

148

What experience do you have with survey equipment and software?

Reference answer

I am proficient in the use of various survey equipment such as total stations, GPS, and LiDAR. I have experience using AutoCAD and other drafting software, including experience creating and editing plans, maps, and other survey-related documents. I am also familiar with GIS and other mapping software. I am able to quickly and accurately produce high-quality documents and maps, and I am able to adapt to new software as needed.

149

What cell edge and cell overlap would you survey for a voice deployment

Reference answer

-65 to -67 dBm

150

What are the benefits of a thorough wireless site survey?

Reference answer

A detailed wireless site survey helps you avoid costly guesswork and repeated trial-and-error deployments, reduce downtime caused by poor or inconsistent WiFi signals, enhance user experience for employees, customers, and devices, ensure compliance with industry regulations and security policies, and optimize your spending on wireless infrastructure by targeting investments where they matter most.

151

What are common security vulnerabilities in wireless networks, and what measures can be taken to mitigate them?

Reference answer

Common vulnerabilities in wireless networks include rogue access points and eavesdropping. To mitigate these, I recommend using WPA3 encryption, keeping firmware updated, and taking steps to segment the network to protect sensitive data.

152

Why should you validate your wireless design with a site survey?

Reference answer

A Wi-Fi site survey validates your wireless design by confirming that predicted performance matches real-world conditions. It generates visual heatmaps to reveal fine-tuning needed before running cabling and installing access points, and it accounts for interference or additional requirements not identified without stepping on site. Validation is cheap insurance and smart risk mitigation against costly redesign processes.

153

What are the three types of wireless site surveys?

Reference answer

The three types of site surveys typically performed while installing a wireless network are: Coverage Survey, Capacity Survey, and Interference Identification.

154

What is a hybrid site survey?

Reference answer

A hybrid site survey is a new term to perform a predictive site survey after an AP on a stick site survey. This method saves time and provides accurate data by allowing you to collect the right data from the venue, understand and measure attenuation, validate the data, know obstruction materials and onsite challenges, and simulate this on the software. It is recommended for pre-deployment and should be followed up with a passive site survey in the post deployment phase.

155

What is Fast Roaming?

Reference answer

- Fast Roaming: Device handshakes with a new AP before roaming to ensure seamless transition and avoid re-authentication.

156

What is the role of IEEE 802.11 standards in wireless networking? Can you explain its evolution over the years?

Reference answer

IEEE 802.11 is a set of standards for wireless networking, defining how devices communicate over Wi-Fi. It evolved from 802.11b in the late '90s, which provided 11 Mbps, to 802.11ax today, offering up to 9.6 Gbps. Each version improved speed, range, and security features, making Wi-Fi more reliable. These standards ensure that devices from different manufacturers can work together seamlessly.

157

What are the key considerations when designing a system for coexistence of multiple wireless protocols in the same frequency range?

Reference answer

Candidates should demonstrate their ability to plan for and mitigate interference, ensuring efficient use of the spectrum and reliable performance for multiple wireless technologies.

158

What is Multi-Link Operation (MLO) in Wi-Fi 7?

Reference answer

Multi-Link Operation (MLO) is a key feature of Wi-Fi 7. It allows devices to connect and communicate over multiple frequency bands or channels simultaneously. This improves data throughput, reduces latency, and increases reliability by enabling devices to dynamically switch between links, depending on the network conditions.

159

What are your weaknesses, and how are you addressing them?

Reference answer

The candidate should identify a genuine weakness and describe concrete actions they are taking to improve, such as training or seeking mentorship.

160

What are the common issues that can affect wireless signal quality?

Reference answer

Common issues include interference from other wireless devices, physical obstructions (e.g., walls, furniture), incorrect access point placement, and network congestion. Addressing these issues often involves optimizing channel settings, adjusting AP locations, and managing network traffic.

161

How do you handle interference in a wireless network?

Reference answer

To handle interference: - - Identify the source of interference using spectrum analyzers. - Change wireless channels to reduce overlap with other networks. - Adjust access point placement and transmit power. - Implement shielding or use different frequency bands to mitigate interference.

162

How do you handle interference in an RF system?

Reference answer

Interviewers should check if the candidate can recognize different types of interference, such as signal overlap or unwanted noise from nearby devices. Look for practical methods the candidate has used, like adjusting frequency bands, power levels, or implementing filtering solutions. A real-world example where the candidate resolved interference effectively would show their hands-on experience.

163

How do you measure project success in the context of RF Engineering, and which key performance indicators (KPIs) do you commonly use?

Reference answer

Look for an understanding of project success metrics specific to RF Engineering, like signal integrity, system efficiency, quality of service, and adherence to timelines and budgets.

164

How do you ensure continuous learning and professional development within your wireless networking team?

Reference answer

“I regularly read publications like 'Wireless Week' and participate in webinars on emerging technologies. I also encourage my team to pursue certifications like CCNA Wireless. To keep everyone informed, I host monthly knowledge-sharing sessions where we discuss new findings and their implications for our projects. This ensures our skills remain sharp and relevant.”

165

How is a WiFi site survey conducted?

Reference answer

A WiFi site survey is conducted using a specialized WiFi site survey software application like NetSpot running on a laptop or mobile device.

166

Explain the concept of wireless network density and its impact.

Reference answer

Wireless network density refers to the number of devices or access points within a given area. High density can lead to increased competition for bandwidth and potential interference, requiring careful planning and management to ensure optimal performance.

167

What is the difference between a traverse and a triangulation?

Reference answer

- Traverse: A series of connected survey lines where angles and distances are measured. The angles are measured directly, while distances are calculated using known lengths. - Advantages: More precise for smaller areas, less susceptible to errors in angle measurement. - Disadvantages: Requires more measurements, less suitable for large areas. - Triangulation: Uses triangles to determine the positions of points. Only angles are measured, and distances are calculated using trigonometry. - Advantages: Suitable for large areas, reduces the number of measurements needed. - Disadvantages: Susceptible to errors in angle measurement, less accurate for smaller areas.

168

What is a wireless site survey?

Reference answer

A wireless site survey involves planning and designing a wireless network to provide adequate wireless coverage, data rates, capacity, roaming, and quality of service. It involves assessing current WiFi performance, identifying obstacles and dead zones, and determining optimal access point locations.

169

What is MIMO, SU-MIMO, MU-MIMO, Beamforming etc

Reference answer

These are some of the most common terms you will come across while reading content on 11n and 11ac. The books i have referenced have all you need on these concepts

170

What techniques do you employ to ensure the accurate calibration of RF measurement instruments?

Reference answer

The candidate is expected to discuss specific calibration procedures, the importance of calibration in signal analysis, and how they ensure precision and accuracy in their measurements.

171

What is Piggybacking in the context of Wi-Fi?

Reference answer

- Piggybacking: Unauthorized use of someone else's wireless connection without their permission.

172

What areas of the business have strong and weak coverage?

Reference answer

A wireless site survey can identify which areas of the business have strong and weak coverage.

173

What is a mesh network, and how does it work?

Reference answer

A mesh network is a type of wireless network where devices (nodes) communicate directly with each other, forming a web-like structure. This creates multiple pathways for data to travel, increasing network reliability and coverage.

174

Tell me about yourself. How would you describe yourself as a person?

Reference answer

The candidate should provide a concise overview of their background, personality traits, and professional attributes that make them a good fit for the role.

175

What is the Shannon-Hartley theorem?

Reference answer

The Shannon-Hartley theorem defines the maximum data rate (capacity) of a communication channel based on its bandwidth and SNR. It provides a theoretical limit on how much information can be transmitted error-free over a given channel.

176

What is the significance of carrier aggregation in LTE?

Reference answer

Carrier aggregation is a technique in LTE that combines multiple frequency bands to increase the total available bandwidth and thus improve data rates. It enhances user experience by providing faster downloads and more capacity for data services.

177

What is a wireless site survey?

Reference answer

A wireless site survey analyzes the radio frequency environment of an area where a Wi-Fi network is deployed. Network teams use site surveys when planning a new network to determine where to install access points (APs).

178

What is the purpose of a wireless access point (AP)?

Reference answer

A wireless access point (AP) provides wireless connectivity to devices within a network. It acts as a bridge between wireless clients and the wired network, allowing devices to connect to the network without physical cables.

179

What are the essential risk management steps you undertake when overseeing an RF Engineering project?

Reference answer

Candidate should demonstrate their approach to identifying, assessing, mitigating, and monitoring risks, with possible RF Engineering-specific illustrations such as dealing with technology obsolescence or regulatory changes.

180

Do you have experience with next-gen wireless protocols such as Wi-Fi 6 or beyond?

Reference answer

Experience with next-gen protocols like Wi-Fi 6 gives an impression of their extensive knowledge on latest wireless standards and their readiness to evolve with changing technology trends.

181

How would team members in the past describe you?

Reference answer

The candidate should share feedback from previous colleagues, highlighting qualities like reliability, collaboration, or technical expertise.

182

What are the main challenges when designing RF systems for high frequencies?

Reference answer

The candidate should highlight real-world challenges they've faced, such as signal degradation, unwanted capacitance, or transmission line issues at higher frequencies. They should mention how they overcame these problems, like adjusting impedance matching, using specialized materials, or redesigning parts of the system to handle high-frequency signals effectively.

183

What is the difference between open and closed networks in wireless terms?

Reference answer

An open network does not require authentication or encryption, allowing any device to connect. A closed network requires authentication (e.g., WPA2) to join, providing a higher level of security by restricting access to authorized users.

184

What is the purpose of recording findings in a wireless site survey?

Reference answer

Taking the extra time to record what you have found will help to identify your current state and where your wireless design is headed.

185

How do you configure wireless QoS for VoIP calls?

Reference answer

To configure wireless QoS for VoIP: - - Define a QoS policy for voice traffic. - Apply the policy to the appropriate WLAN or SSID. - Use priority tags (e.g., DSCP values) to prioritize voice packets. - Configure access points and controllers to enforce QoS settings.

186

Explain the concept of GPS and its application in surveying.

Reference answer

Global Positioning System (GPS) utilizes satellites orbiting the Earth to determine precise locations. In surveying, GPS receivers measure the time it takes for signals from multiple satellites to reach the receiver, allowing it to calculate its position in three dimensions (latitude, longitude, and elevation). GPS is widely used for: - Control Surveys: Establishing accurate control points for geodetic surveys. - Topographic Mapping: Creating detailed topographic maps using GPS data. - Construction Layout: Setting out building foundations and other structures with high precision. - Land Management: Monitoring land boundaries and defining property lines. - Disaster Response: Assisting with damage assessment and mapping after natural disasters.

187

Have you completed any certifications specific to wireless communication or networking systems?

Reference answer

Certifications indicate the professional's dedication towards learning and staying updated in their field. If they possess certifications like CCNA Wireless, CWNA, CCNP Wireless, then it's evident that they're trained in handling wireless communication and networking systems in a professional context.

188

What is the importance of scale in surveying and mapping?

Reference answer

Scale in surveying and mapping refers to the ratio between the distance on a map or plan and the corresponding distance on the ground. It determines the level of detail that can be represented on the map and is crucial for: - Accuracy: Ensuring the map or plan accurately represents the real-world dimensions and features. - Clarity: Presenting the information in a legible and understandable way, based on the scale chosen. - Data Management: Managing and storing map data efficiently, depending on the level of detail required. - Communication: Communicating the surveyed information effectively to engineers, architects, or other stakeholders.

189

Explain the significance of 320 MHz channels in Wi-Fi 7.

Reference answer

Wi-Fi 7 supports channel widths of up to 320 MHz, which is double the maximum channel width of 160 MHz supported in Wi-Fi 6E. Wider channels allow for more data to be transmitted simultaneously, leading to higher data rates and increased overall network capacity. This is particularly beneficial for bandwidth-intensive applications like 8K video streaming, virtual reality, and large-scale IoT deployments.

190

Describe the process you would use to analyze a noisy RF signal.

Reference answer

Candidates should demonstrate their understanding of the tools and methodologies for isolating and analyzing sources of noise in RF signals. Clear steps and relevant techniques such as Fourier analysis or filtering are expected.

191

What is the difference between active and passive site survey?

Reference answer

A passive survey collects information about the signals within the environment itself. According to Wikipedia, a site survey application passively listens to WLAN traffic to detect active access points, measure signal strength and noise level. An active survey (also referred to as a ‘live' survey) collects information around specific signals within the environment when it's in full working order. It uses an active/live access point to measure wifi signal strength, coverage and general performance.

192

What is a Capacity Survey?

Reference answer

A capacity survey determines how many users can connect to a single access point and expect decent throughput and data rates. If clients cannot connect to your WLAN at an acceptable data rate, they will quickly give up trying, which could potentially impact productivity if the problem goes unresolved. It is essential not to overload the wireless access points in your common areas with too many clients, as that can significantly decrease data rates.

193

What is the frequency range of the 802.11g standard?

Reference answer

2.4GHz Frequency.

194

What are different Wi-Fi generations?

Reference answer

Wi-Fi generations include Wi-Fi 1 (802.11b), Wi-Fi 2 (802.11a), Wi-Fi 3 (802.11g), Wi-Fi 4 (802.11n), Wi-Fi 5 (802.11ac), and Wi-Fi 6 (802.11ax). Each generation offers improvements in speed, capacity, and efficiency, with newer generations supporting higher data rates and better performance in dense environments.

195

Describe a time you worked effectively as part of a team to solve a technical problem.

Reference answer

“During my internship at a local telecom company, I worked on a team project to optimize the wireless network for a client. I was responsible for conducting a site survey and gathering data on signal strength. We faced challenges with interference from nearby buildings, but through regular team meetings and brainstorming sessions, we devised a solution that involved repositioning access points. The project was successful, leading to a 30% increase in coverage, and I learned the value of effective communication in a team setting.”

196

What are the best practices for performing a wireless site survey?

Reference answer

Best practices for performing a wireless site survey include: - Use separate adapters to perform passive site survey on 5 GHz and 2.4 GHz to save time - Perform site survey on both frequency bands 2.4 GHz and 5 GHz as their nature is different - Set the right values for signal propagation assessment to get quality data - Walk at least 10-15 dBm above the designed threshold towards the cell boundary for accurate results - Always survey on the access point and antenna planned for production network, ideally on the least capable device - Configure access points with right data rates and lower transmit power level (below 14 dBm) to have buffer - Lower transmit power on 2.4 GHz slightly than 5 GHz during survey - Post site survey, create a static channel plan for 2.4 GHz radios and disable a few if required - Perform spectrum analysis to understand non-wifi interference (like radar, microwave, jammers)

197

Describe a time when you had to implement a wireless protocol in a challenging RF environment. How did you ensure the reliability of the communication?

Reference answer

Candidates must demonstrate situation assessment skills and the application of specific RF engineering principles to overcome environmental challenges.

198

Have you worked with 5G wireless networking? Please describe your experience.

Reference answer

5G is the latest development in wireless networking that promises faster speeds and more reliable connections. The candidate's experience with 5G clearly depicts their knowledge about advanced wireless technologies.

199

Describe in detail what happens when you open the web browser on a client to surf google.com

Reference answer

This article gives a very in-depth breakdown of the process. You just need to know the high level details mainly around DNS and HTTP request

200

What does a wireless site survey show?

Reference answer

The initial input to a wireless site survey includes a blueprint that shows the placement of walls, desks and other equipment. The survey then produces a heat map, which is a color-coded map that shows signal strength throughout the area based on where APs are placed. The display also shows network noise levels, signal-to-noise ratios, interference, throughput, data rates, packet losses and retries. It can also produce a spectrum analysis that measures the strength of Wi-Fi signals and interference from nearby sources, and detect devices that shouldn't be connected to the network.

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Top Interview Questions for Wireless Site Survey Engineers | SPOTO

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Top Interview Questions for Wireless Site Survey Engineers | SPOTO

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