Analog Modulation And Frequency Modulation - Assignment Solution

Answer 5:

A CRC (Cyclic Redundancy Check) is a code with is commonly used in order to detect if there is any accidental change made to data while transmitting the data. When data is being sent from a sender, a CRC attached to the data packet to in order to identify the accidental damage to raw data.

The sender performs a calculation on data and attaches it with the result value while receiver performs the same calculation to compare the result from the original value. If the 2 values do not match, then the transmission error occurs and the receiver rejects the data. 

Sender Receiver

Answer 6:

Message = 10111100, Pattern = 11011 -> 1 + x = x^3 + x^4 = > FCS length = 4

11011 | 10111100|0000 

                11011

                  11001

                  11011

                         10000

                         11011

                            10110

                            11011

                               11010

                               11011

                                         10 FCS

Answer 8:

Ad-hoc and Infrastructure mode are slightly different to one another. Ad-hoc mode is peer to peer while infrastructure mode has an access point and all the devices are connected to that access point. As Ad-hoc mode doesn’t require an access point, all the devices are connected to each other wirelessly. Hence, Ad hoc mode is not a permanent implementation of a network and is considered to be valuable in short term. 

On the other hand, Infrastructure mode is considered to be permanent solutions. It is also considered to be more reliable as all the devices are connected to an access point. Therefore, most of the firms prefers Infrastructure mode over Ad-hoc mode due to reliability and long lasting nature.