Free CWISA-103 sample questions

Correct answer: The ADR mechanism is incorrectly increasing the data rate (lowering the spreading factor) due to fluctuating link conditions, causing messages to fall below the receiver sensitivity.

Adaptive Data Rate (ADR) in LoRaWAN adjusts the spreading factor (SF) to optimize battery life and network capacity. In unstable RF environments, such as an open yard with moving metal containers causing reflections and fading, the ADR algorithm might misinterpret a temporarily strong signal as a stable link improvement. It would then command the sensor to use a lower SF (higher data rate), which requires a better signal-to-noise ratio. When the temporary good condition vanishes, the signal is too weak to be demodulated at the lower SF, leading to packet loss. The log pattern of data rate changes followed by silence is a classic symptom of overly aggressive ADR.

Correct answers: Implementing network slicing to dedicate resources for AMR control traffic.; Deploying the User Plane Function (UPF) at the network edge, close to the AMRs.

Network slicing is a key 5G feature that allows the creation of virtual end-to-end networks tailored to specific applications. For URLLC, a slice can be configured with dedicated resources and quality of service (QoS) parameters to guarantee low latency and high reliability for the critical AMR control data, isolating it from other less critical traffic.

Deploying the UPF, which handles data packet routing and forwarding, at the network edge (a concept known as Multi-access Edge Computing or MEC) significantly reduces latency. By processing data locally instead of sending it to a centralized core network, the round-trip time for AMR control commands is minimized, which is essential for URLLC.

Correct answer: False

False. While operating multiple radios simultaneously can increase instantaneous power draw, MLO can significantly reduce overall energy consumption for battery-powered IoT devices. By aggregating links, the device can transmit its data much faster and return to a low-power sleep state more quickly. This reduction in active time often outweighs the higher instantaneous power draw, leading to net power savings over time.

Correct answer: Implement a Bluetooth Low Energy (BLE) based RTLS using battery-powered BLE asset tags. The existing Wi-Fi 6E APs, which have integrated BLE radios, will listen for tag advertisements and forward the data to a central location engine.

This solution meets all requirements. BLE tags provide multi-year battery life. Leveraging the integrated BLE radios in the existing Wi-Fi 6E APs requires no new cabling. The APs act as gateways, collecting BLE data without the tags needing to connect to the secure Wi-Fi network, thus bypassing WPA3-Enterprise complexities for the tags themselves. RSSI-based locationing from a dense AP deployment can achieve the required room-level accuracy. The data can then be sent over the existing network to the management platform.

Correct answer: 24 dBm

The calculation is as follows: 1. Convert transmitter power to dBm: 100 mW = 20 dBm (since 10 * log10(100) = 20). 2. Calculate total cable loss: 10 meters * 0.5 dB/meter = 5 dB. 3. Calculate EIRP: EIRP (dBm) = Tx Power (dBm) - Cable Loss (dB) + Antenna Gain (dBi). 4. EIRP = 20 dBm - 5 dB + 9 dBi = 24 dBm.

Correct answer: A faulty microwave oven operating near the Zigbee coordinator.

Microwave ovens are a notorious source of wideband RF interference in the 2.4 GHz band. A faulty or poorly shielded oven can raise the noise floor across the entire band, affecting all Zigbee channels, as well as Wi-Fi and Bluetooth. Wi-Fi interference would typically appear as a distinct 20 or 40 MHz wide signal, not a consistently high noise floor across all channels.

Correct answer: RPL (Routing Protocol for Low-Power and Lossy Networks)

RPL is the standard routing protocol for 6LoWPAN and was designed by the IETF specifically for the constraints of Low-Power and Lossy Networks (LLNs). It builds a Destination Oriented Directed Acyclic Graph (DODAG) and has modes of operation (storing and non-storing) that allow it to efficiently manage routes for sleepy end devices, minimizing the communication required and thus conserving battery life.

Correct answer: LoRaWAN

LoRaWAN is a Low Power Wide Area Network (LPWAN) technology specifically designed for long-range (kilometers), low-power communication. Its use of Chirp Spread Spectrum (CSS) modulation provides excellent resilience to interference and deep indoor penetration, making it ideal for sending small, infrequent data packets in challenging urban environments.

Correct answer: An attacker can passively decrypt all network traffic, potentially exposing sensitive operational data.

The Zigbee network key is used to encrypt the network layer and application layer data frames. If an attacker knows this key, they can use a Zigbee sniffer to capture and decrypt all traffic on the network. This allows them to not only view sensitive data but also to analyze traffic patterns to plan more sophisticated attacks, such as injecting malicious commands.

Correct answer: To receive messages from publishers and filter and forward them to subscribed clients.

The MQTT Broker is the central hub in a publish/subscribe messaging system. Its core responsibility is to manage the flow of messages. It receives messages published by clients (like sensors) on specific 'topics' and then forwards those messages only to clients that have subscribed to those topics. This decouples the message producers from the consumers.