a$.$ Consider the use of fixed$-$length packets. In this case, the overhead consists of the header octets. Define

$L=$ Data field size of the cell in octet

$H=$ Header size of the cell in octets

$x=$ Number of information octets to be transmitted as a single message

Derive an expression for $N.$ Hint: The expression will need to use the operator $*,$ where $[Y]=$ the smallest integer greater than or equal to $Y.$