Wireless Communications. Wireless embedded systems must operate in a variety of environments that can affect their communications performance. In this problem, we explore some factors that an embedded engineer might consider when designing a system to operate in these environments. For quantitative questions, be sure to show your work with sufficient details so your reasoning is clear. (a) Assuming a free-space (line of sight) environment, what is the required transmit power needed to achieve a -90 dBm received power at a distance of 100 m, assuming that both transmit and receive antennas are ideal isotropic radiators (G tx = G rx = 1 = 0 dB) and the transmit frequency is 900 MHz? What would be required transmit power for a 2.4 GHz transmit frequency? What about 2.4 GHz but at a range of 1 km? Recall that wavelength ( l) and frequency (f) are related as follows: f l = c, where c is the speed of light. Ptx (900 MHz, 100 m): _______________ Ptx (2.4 GHz, 100 m): _______________ Ptx (2.4 GHz, 1 km): _______________ (b) Assume that your transmitter from part (a) indeed transmits with enough power to ensure exactly -90 dBm is received at some distance