When answering the questions, please provide in detail answers with full steps. The questions follow the book: A. Goldsmith, Wireless Communications, Cambridge University Press, 2005. Use equations found in this textbook and answer the questions by writing the equation number that was used. If an equation that does not exist in the textbook is to be used, please derive that equation from one of the equations that are stated in the book. Show all steps in detail. Question: A QPSK signal constellation with Gray mapping is used to transmit information over an AWGN channel. The system uses rectangular pulses (raised cosine pulses with Beta = 0) for the transmission. a) If the available bandwidth is B = 40KHz, what is the maximum bit rate that can be transmitted using this scheme? b) To double the bit rate using the same bandwidth and pulse shaping, we replace QPSK with MPSK (M> 4). What is the value of M? To maintain the same probability of symbol error, how much increase in the average transmitted power is required? c) In part (b), if we still use Gray mapping, how does the BER change?