Modeling of nondirected wireless infrared channels

Abstract

Abstract-We show that realistic multipath infrared channels can be characterized well by only two parameters: optical path loss and rms delay spread. Functional models for the impulse response, based on infrared reflection properties, are proposed and analyzed. Using the ceiling-bounce functional model, we develop a computationally efficient method to predict the path loss and multipath power requirement of diffuse links based on the locations of the transmitter and receiver within a room. Use of our model is a simple, yet accurate, alternative to the use of an ensemble of measured channel responses in evaluating the impact of multipath distortion.

Effect of transmitter positions on received power and bandwidth in diffuse indoor optical wireless systems

“…In this work, estimation of the average received power is an extension of Ref (Carruthers and Kahn 1997). In order to simplify channel bandwidth computations in CB model, we suggest some modifications by combining the results of CB model with some statistical models.…”

“…We also extended the Ceiling bounce model proposed by Carruthers Kahn (1997) so as to calculate the impulse response of diffuse channels in multiple transmitter environments. We shall refer to this extension as the Extended Ceiling Bounce model(ECB) and use it for computing received power as well as the 3 dB channel bandwidth.…”

“…Some of the existing algorithms to compute the impulse response are the recursive method (Barry and Kahn 1993) (Carruthers and Kahn 1997) and Iterative Site-Based Modeling (Carruthers and Kannan 2002). All these models consider only the single transmitter environment.…”

“…In this section we suggest a modification to the Ceiling bounce model of Carruthers and Kahn (1997) for computing channel parameters, such as the channel impulse response, channel bandwidth and the average received power. In this work, estimation of the average received power is an extension of Ref (Carruthers and Kahn 1997).…”

“…Also, diffuse systems are flexible and can be used for ad hoc networks. However, a diffuse system can incur a very high optical path loss, typically 50-70 dB for a horizontal separation distance of 5 m (Carruthers and Kahn 1997). The path loss is increased further if a temporary obstruction, such as a person, obscures the receiver such that the main signal path is blocked, a situation referred to as shadowing.…”