If my data has long chain of 1's or 0's. Can the data be modulated and transmitted as it is. Will this have any effect of the receiver adc as this may increase dc value of the signal or any other block in the receiver chain? should the data be scrambled?
A dominant concern with long runs of ones or zeros is the ability of the receiver to establish symbol timing. The receiver clock is independent from the transmitter clock, so without transitions in the data the receiver will not be able to determine the clock used in the transmitter for each symbol, and will ultimately drift off. Whitening the data has other benefits for equalization and overall efficiency.