CC5901 Low-Power and Wide-Area IoT Communications Network

1. For an LPWA application, if each node is assigned with a 150-Hz channel, and you have measured that the average signal-to-noise ratio is 5dB, what is the average data rate it can transmit?

2. If the data of a deployed LPWA temperature monitoring system have missing data from some sensors, what you will investigate to identify the problem? (Hint: Battery? Network access protocol?)

3. In a deployed sensor system, assuming no malfunction in any of the base station or sensor nodes of a network, is it possible for a data packet to be delivered to a wrong destination in the cloud?

4. Describe what a directional antenna is? Discuss whether it is possible to incorporatedirectional antennas in an LPWA system? What is the advantage and what is the possible drawbacks?

5. What is multipath fading? Do you think whether multipath fading problem in the LPWA IoT network is assignificant as the cellar network such as 4G LTE? Please list your reasons.

6. Is bit error rate (BER) important for the LPWA system? What is the design challenge when linking the BER to a practical LPWA system? (Hint: Think about what kind of error control codes can minimize the BER for a given channel and whether these types of codes can be directly applied to the LPWA IoT system.)

7. Discuss the Difference between DSSS and FHSS? Can these types of techniques be used in the LPWA system? What is the benefit and what are the possible drawbacks? (Hint: Think about granting free access from the sensor to the base station)

8. Assume now we would like to design a smart city IoT system and our goal is to measure the temperature at different locations in the city. How will you design this system? For the existing LPWA technology available on the market, such as LoRaWAN, NB-IoT, and SigFox, which ones will you choose and why? In case if we want to add another function which is to monitor the traffic conditions in various locations in the city, can we do this using the same system as designed for measuring the temperature? (Hint: Think about different system requirements. In some cases we may do computations at the sensor first and only transmit results to the cloud.)