| Having the wide bandwidth ,flexible ,convenient and great safety properties. The wireless infrared communication take a new direction in indoor wireless communication development , and has a great promising application.In the paper ,firstly, studying and analyzing the indoor wireless infrared channel. Based on infrared diffuse reflection properties, Modeling of the infrared diffuse channels impulse response. And using the channels functional model, We develop a computationally efficient method to predict the path loss and multipath power requirement of diffuse links based on the locations within a room. And getting two characteristic parameters: optical path and r.m.s delay spread. Meanwhile, We classify the five kinds of waveforms as transmitter pulse. And get the characters of BER in different transmitted waveforms.Secondly , The paper perform a review of the most common modulation methods used in such systems , including OOK , PPM , overlapping-PPM , A hybrid modulation scheme called APPM . And present the expressions for the probability of symbol error and channel capacity.Finally, We mainly discuss the system performance in the presence of background light. In this system ,The major impediment is noise induced by fluorescent lights, A reasonable solution for overcoming this impairment is to pass the preamplifier output through a high-pass filter. However, this induces baseline wander. We propose to mitigate baseline wander either by using a line code or by using active baseline restoration. And improve the performance by use of the decision feedback equalization. In the end ,We introduce two methods of communicating to multiple users by TDMA or via a packet-based method. |
PDF Full Text Request