An ultra-wideband space-variant multipath indoor radio channel model

Abstract

Absfrucf-We present a generic ultra-wideband (LWB) of a room is such that echoes caused by certain paths may multipath radio channel model that has been designed for he appreciably distinguishable from each other. This aplink-level simulations and is suited for indoor environments, plies dee.g. for WPAN aPP1ications. It lays. For example, in LOS conditions, the direct path may responses (IR) and transfer functions. The model is of a hybrid type and combines a statistical approach to model dense multipath and a simple quasi-deterministic method to these echoes. model strong individual echoes. These echoes are important with increasing the Probability for Paths to obtain a realistic spatial (Doppler) behavior. The archi-increases because the corresponding Path distances get tecture of the model facilitates the application to U W B longer, which in turn increases the probability of interac-MIMO analyses. For a few scenarios (e.g.. intra-omce and tions with the environment. Consequently, the onset of inter-office transmission), site-specific parameter profiles the inevitable dense multipath regime is shifted towards are given that have been derived from measured data.larger delays. For medium to large excess delays, the average power delay profile (APDP) fits quite well into the exponential decay scheme that has been observed for A distinguishing feature of the UWB indoor radio wideband channels (cf. e. g. [3]). For small excess delays, channel is that certain individual paths are recognizable however, UWB APDP's tend to have a more spiky apand resolvable in the measurements. In contrast to dense pearance caused by individual echoes. Yet the first path multipath contributions, these paths exist individually corresponding to LOS conditions may be followed by over distances larger than a wavelength. In this document some trailing multipath contributions caused e.g. by the we give a self-contained specification of a multipath ra-mechanical antenna support. Depending on the environdio channel model that has been designed to incorporate ment and Tx-Rx distance, the direct path, floor, ceiling this property, i.e., the delay and amplitude changes of and wall reflections may be recognizable. individual echoes corresponding to different positions of An example for a LOS UWB channel AE'DP illustratthe transmitter or receiver are accounted for to produce a ing these points is given in Fig. 1. Fig. 2 shows 150 adjadecent Doppler behavior. cent color-coded power delay profiles for the same chan-The model is based on measurement data (cf.[ 2 ] ) that ne1 obtained by displacing one antenna over a linear diswere obtained in office environments with line-of-sight, tance of 150 cm. The individual echoes and the dependnon-line-of-sight, and intermediate conditions, and a dis-ence of the corresponding delays from the spatial positance between transmitter (Tx) and receiver (Rx) below tion (including a slight curvature of the LOS trace due to 10 m for a frequency range from 1 to 11 GHz.an appreciable change of the Tx-Rx distance over the ...

Modeling the Ultra-Wideband Outdoor Channel: Model Specification and Validation

“…gives rise to a more regular structure. Nevertheless, for want of a better model, we employ this uniform distribution in the following, while noting that the cluster location can be adapted based on future measurements, or even based on locationspecific geometrical information, in the spirit of [10].…”

“…(1). This is a simplified approach since, in real scenarios, each received pulse can have its own decay exponent [29]; nevertheless since these individual exponents are difficult to estimate we opt for a general decay exponent as in [10]. In order to estimate the value of , we calculated the exponent of each individual frequency response and averaged over that ensemble which resulted in = 0.95.…”

“…A large number of generic channel models has been proposed in the literature [3]- [5]. In particular, for UWB channels, tap delay line channel models with regular tap spacing [6], [7], Saleh-Valenzuela-type channel models [8], [9], as well as geometry-based models [10] have been used. However, none of the existing generic modeling approaches is completely suitable to explain all the features of our measurement results.…”

“…However, none of the existing generic modeling approaches is completely suitable to explain all the features of our measurement results. We therefore introduce a new model that bears some similarities to [10]- [12] in that it is also geometry-based, and considers discrete path components as well as diffuse components. However, we introduce several novel concepts for UWB channel modeling: (i) cluster "beampatterns" describing the directional dependence of the radiation emanating from a cluster, and (ii) shadowing regions that represent the largescale attenuation of the LOS for certain TX/RX locations.…”

Channel model and capacity for broadband indoor MIMO-WLAN systems based on measurements at 2.4 GHz

“…The WLAN indoor channel model is closer related to the ultra wide band (UWB) channel than to the mobile channel. A paper dealing with UWB channel modelling [1] is also suggesting a more deterministic view. Even if a small movement is considered in the WLAN channel this could be determined by a channel estimation and the system can adapt to this slowly varying channel.…”