Reference no: EM132362348
Questions -
Q1. Consider a wireless LAN system with the following system specifications: fc = 5 GHz B = 20 MHz GTX = 2dB GRX = 2dB Fading margin = 16 dB Path loss = 90 dB PTX = 20 dBm TX losses: 3 dB Required SNR: 5 dB. What is the maximum admissible RF noise figure?
Q2. A TX is located 20 m from a 58-m-high brick wall (εr = 4), while an RX is located on the other side, 60 m away from the wall. The wall is 10 cm thick and can be regarded as lossless. Let both antennas be of height 1.4 m and using a center frequency of 900 MHz.
(a) Considering TE waves, determine the field strength at the RX caused by transmission through the wall, Ethrough.
(b) The wall can be regarded as a semi-infinite thin screen. Determine the field strength at the RX caused by diffraction over the wall, Ediff.
(c) Determine the ratio of the magnitudes of the two field strengths.
Q3. A radio system is usually specified in such a way that an RX should be able to handle a certain amount of Doppler spread in the received signal, without losing too much in performance. Assume that only the mobile RX is moving and that the maximal Doppler spread is measured as twice the maximal Doppler shift. Further, assume that you are designing a mobile communication system that should be able to operate at both 900 MHz and 1,800 MHz.
(a) If you aim at making the system capable of communicating when the terminal is moving at 200 km/h, which maximal Doppler spread should it be able to handle?
(b) If you design the system to be able to operate at 200 km/h when using the 900-MHz band, at what maximal speed can you communicate if the 1,800-MHz band is used (assuming the same Doppler spread is the limitation)?