LoRaWAN and LoRa Interview Questions and Answers

This document provides a set of interview questions and answers related to LoRaWAN and LoRa technologies, designed to help candidates prepare for job interviews in this field.

Question 1: What is LoRaWAN?

Answer: LoRaWAN is a Low Power Wide Area Network (LPWAN) technology characterized by its long range (approximately 10 to 30 miles), low power consumption (offering 15-20 years of battery life), and high capacity (supporting millions of messages per gateway). It employs the AES-128 algorithm for privacy and security against intrusions.

Question 2: What is LoRa?

Answer: The term “LoRa” refers both to the LoRaWAN technology and the modulation technique it utilizes, specifically Chirp Spread Spectrum (CSS) modulation. This modulation allows for varying data rates by using different spreading factors. Frequency Shift Keying (FSK) is another modulation scheme used in LoRaWAN.

Question 3: What is a LoRaWAN gateway?

Answer: A LoRaWAN gateway acts as a relay, forwarding received radio packets to the network server through a backbone connection. It receives radio packets from the air and transmits them to the network server without any processing. Similarly, it doesn’t modify payloads received from the network server before transmitting them over the air. The gateway performs the necessary RF conversion based on the specific frequency band being used.

Question 4: What are the frequency bands used in LoRaWAN?

Answer: LoRaWAN operates on different frequency bands depending on the region. These include 433 MHz, 863 to 870 MHz, 902 to 928 MHz, and 779 to 787 MHz.

Question 5: What is the LoRaWAN frequency used in INDIA?

Answer: In India, the frequency channels used for LoRaWAN are 865.0625 MHz, 865.4025 MHz, and 865.985 MHz.

Question 6: What is the LoRaWAN frequency used in USA?

Answer: In the USA, LoRaWAN utilizes frequency channels within the range of 902 to 928 MHz.

Question 7: What is the LoRaWAN frequency used in CHINA?

Answer: China uses the CN779-787 band (779 to 787 MHz) for LoRaWAN systems. Specific channel frequencies include 779.5 MHz, 779.7 MHz, and 779.9 MHz.

Question 8: What is the LoRaWAN frequency used in Europe?

Answer: Europe utilizes two radio frequency bands for LoRaWAN: 863 to 870 MHz and 433 MHz. In the EU868 MHz band, channels at 868.1 MHz, 868.3 MHz, and 868.5 MHz are allocated. In the EU433 band, channels at 433.175 MHz, 433.375 MHz, and 433.575 MHz are allocated.

Question 9: What is the LoRaWAN frequency used in Russia?

Answer: Russia uses the RU864-870 band, with allocated channel frequencies at 868.9 MHz and 869.1 MHz.

Question 10: What is the difference between LoRa and LoRaWAN?

Answer: LoRa refers to the modulation technique used to achieve different data rates, while LoRaWAN refers to the network protocol designed for wide-area coverage (long distance) and low power consumption in IoT/M2M applications. LoRa modulation is also known as CSS modulation.

Question 11: What is the difference between LoRaWAN and Zigbee?

Answer: LoRaWAN provides a long range (2 to 5 km in urban environments and up to 15 km in rural environments), while Zigbee’s range is limited to about 100 meters.

Question 12: Can you explain LoRaWAN network architecture, its elements, and network interfaces?

Answer: The LoRaWAN network architecture comprises end devices, gateways, a network server, a join server, and an application server.

The following diagram illustrates the different network interfaces between these elements:

Question 13: What are the different classes supported in LoRaWAN devices?

Answer: LoRaWAN devices support three classes: Class A, Class B, and Class C.

Question 14: Which are the roaming types supported by LoRaWAN?

Answer: LoRaWAN supports two types of roaming: passive roaming and handover roaming.

Question 15: Which are LoRaWAN Certification test providers in the world?

Answer: Some of the LoRaWAN certification test providers include 7layers, Allion Labs, DEKRA Ltd, IMST GmbH, TTA, TUV, Bureau Veritas, AT4 Wireless, and Etteplan.

Question 16: Which are LoRaWAN Certification test providers in INDIA?

Answer: TUV and DEKRA (India) Pvt. Ltd. provide network service in India.

Question 17: Narrate advantages (i.e., benefits) and disadvantages (i.e., drawbacks) of LoRaWAN technology?

Answer:

Advantages:

• Long range
• Low power consumption
• High device capacity
• Adaptive data rate
• Global frequency coverage
• Low cost

Disadvantages:

• Low data rate
• Low latency

This set of LoRaWAN interview questions and answers is helpful for both freshers and experienced professionals seeking LoRaWAN-related job positions.