| In recent years, IPTV has got a great development in the3G network, but due to slow network transmission rate, which limits the IPTV signal quality. With4G licenses’ issued, the4G network is rapidly spread to the country, a wireless network data rate will be increased significantly, this is undoubtedly a great opportunity to the development of IPTV.As a new media, while IPTV brings people convenience,it also recommends signal quality requirements. Like radio and communication, IPTV signal is in the form of electromagnetic wave in air, in the process of transmission, it-will face the problem of fading and noise disturbance, resulting in signal power attenuation and error increase. In order to reduce the signal error rate as a starting point, this paper analyzes the modulation method for signal fading effect, and combines with wireless signal transmission model, it is concluded the relationship of different modulation mode, the signal transmitted power and received signal bit error rate.This paper chooses the MPSK modulation mode, analyzes the relationship between the modulation order and bit error rate, gets signal-to-noise ratio curve,and is prepared for the signal power decline calculation.Secondly, this paper introduces several commonly used wireless signal transmission model, chooses Cost231-Walfisch-Ikegami model and makes it simplified,it draws a simplified model of the actual engineering application, and compares the simplified model with the original model, and analyses its feasibility.Finally,it uses the simplified model and channel fading formulas to get the relationship signal transmit power and receiving signal, then carries on the analysis. Using this relationship, the requirement of the receiver on the bit error rate to determine the transmitting power, we can reduce unnecessary power consumption. |
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