Solution:$-$

The balance strategy would be OFDM, on the grounds that it is more impervious to ISI than QAM. The quantity of subcarriers would be $48,$ in light of the fact that each subcarrier can convey $1$ Mbps of information.

Clarification:

In a correspondence framework, the transmission capacity is the scope of frequencies over which the framework can work. The rolloff factor is a proportion of how the transfer speed of the framework diminishes with expanding recurrence. The information rate is how much information that can be communicated over the framework in a given timeframe. To send at an information pace of $4\mathrm{.}8$ Mbps$,$ the balance procedure would be OFDM.

OFDM is more impervious to ISI than QAM. The quantity of subcarriers would be $48,$ in light of the fact that each subcarrier can convey $1$ Mbps of information. OFDM is a balance procedure that is impervious to ISI since it sends information over various subcarriers. The subcarriers are dispersed separated in recurrence, and each subcarrier conveys a part of the information. The information on each subcarrier is tweaked utilizing QAM.

The quantity of subcarriers is picked so the most extreme postpone spread is obliged. For this situation, the greatest defer spread is $25$s$.$ The quantity of subcarriers is $48,$ and that implies that each subcarrier is separated by $25$s$/48=0\mathrm{.}52$s$.$ This is adequate to oblige the most extreme defer spread. QAM is a tweak procedure that is utilized to regulate the information on each subcarrier. QAM encodes two pieces of information for each image.

The quantity of images is picked with the goal that the information rate is $4\mathrm{.}8$ Mbps$.$ For this situation, the quantity of images is $4\mathrm{.}8$ Mbps$/2$ pieces for every image $=2\mathrm{.}4$ million images. The information pace of $4\mathrm{.}8$ Mbps is accomplished by utilizing $48$ subcarriers, each conveying $1$ Mbps of information. The greatest postpone spread is obliged by dispersing the subcarriers separated by $0\mathrm{.}52$s$.$ QAM is utilized to tweak the information on each subcarrier, and the quantity of images is picked so the information rate is $4\mathrm{.}8$ Mbps$.$