$2.$ Consider a LoRaWAN node that uses SF$8/250$ KHz$.$ Assuming a code rate of $3/5,$ answer the following questions:

A$.$ Compute the symbol duration used by the node.

B$.$ Compute the data rate used by the node.

C$.$ If the payload sent by each message is $250$ B $,$ how many messages per day can the node send, if a duty cycle of $\backslash (1\backslash \%\backslash )$ is enforced.

D$.$ Suggest a way to double the number of messages that can be sent per day by one node without changing the message size.

$3.$ Assume the following IPv$6$ PDU is to be processed by $6$LoWPAN in order to be inserted into an IEEE $802\mathrm{.}15\mathrm{.}4$ frame. The PDU is represented in hexadecimal format.

A$.$ Show in a table the value of each field of the above packet including the network layer header, transport layer header, and the application data.

B$.$ Determine the resulting PDU after compression if the following rules are used:

a$.$ Both source and destination addresses are not present $($derived from the data link layer addresses instead$)$

b$.$ The traffic class and flow label are not used.

c$.$ No IPv$6$ extension is used.

d$.$ Both source and destination ports in the transport layer are compressed.

Show the adaptation layer headers, the IPv$6$ header, transport header, and the application data.

C$.$ Determine the size and savings resulting from applying header compression.