An extension of the RiMAX multipath estimation algorithm for ultra-wideband channel modeling

Abstract

This work presents an extension of the high-resolution RiMAX multipath estimation algorithm, enabling the analysis of frequency-dependent propagation parameters for ultra-wideband (UWB) channel modeling. Since RiMAX is a narrowband algorithm, it does not account for the frequency-dependency of the radio channel or the environment. As such, the impact of certain materials in which these systems operate can no longer be considered constant with respect to frequency, preventing an accurate estimation of multipath parameters for UWB communication. In order to track both the specular and dense multipath components (SMC and DMC) over frequency, an extension to the RiMAX algorithm was developed that can process UWB measurement data. The advantage of our approach is that geometrical propagation parameters do not appear or disappear from one sub-band onto the next. The UWB-RiMAX algorithm makes it possible to re-evaluate common radio channel parameters for DMC in the wideband scenario, and to extend the well-known deterministic propagation model comprising of SMC alone, towards a more hybrid model containing the stochastic contributions from the DMC’s distributed diffuse scattering as well.Our algorithm was tested with synthetic radio channel models in an indoor environment, which show that our algorithm can match up to 99% of the SMC parameters according to the multipath component distance (MCD) metric and that the DMC reverberation time known from the theory of room electromagnetics can be estimated on average with an error margin of less than 2 ns throughout the UWB frequency band. We also present some preliminary results in an indoor environment, which indicate a strong presence of DMC and thus diffuse scattering. The DMC power represents up to 50% of the total measured power for the lower UWB frequencies and reduces to around 30% for the higher UWB frequencies.

A Survey of Dense Multipath and Its Impact on Wireless Systems

“…However, in [139], DMC has been demonstrated to contribute significantly to the total received power in NLoS condition at mmWave bands, and the contribution of DMC can be higher with increasing frequency. In the cm-wave band (3.1 GHz to 10.6 GHz), [112] observed that the DMC power ratio decreases with increasing frequency. At present, there is no unified conclusion on the relationship between DMC and frequency, therefore, it still needs further study.…”

“…More detailed information on RiMAX can be found in [4], and the influences of incomplete and inaccurate data models on RiMAX are discussed in [15]. Based on the RiMAX algorithm framework, several extensions have been made for joint estimation of DMC parameters in frequency, angular, as well as polarization domains [21], [112].…”

“…An office and a laboratory 3.6 GHz; 200 MHz [10] The DMC power ratio increases with frequency but decreases with distance An underground convoy 32.5 GHz; 15 GHz [12] The DMC ratio varies between 23% and 38% in LoS scenarios, varies between 27% and 70% in obstructed line-of-sight (OLoS) scenarios, varies between 57% and 64% in NLoS scenarios A workshop 3 GHz; 100 MHz [14] The DMC ratio is about 15% An urban macrocell 2.53 GHz; 20 MHz [20] The residual power ratios remained more than 30%, the contributions of DMC are not negligible in X-band Three indoor environments 11 GHz; 400 MHz [48], [49] The mean power percentage of the DMC is around 30% Indoor office environment 3.6 GHz; 200 MHz [112] In LoS (NLoS) scenario, the DMC ratio is 50% (60%) for lower UWB frequencies, and 30% (50%) for the higher UWB frequencies An indoor environment Frequency ranges from 3.1 to 10.6 GHz, the number of frequency sub-bands is 30, sub-bandwidth is 250 MHz [114] In both LoS and NLoS conditions, the DMC power ratio increases when the distance between the transmitter and the receiver increases Indoor office environment with large lobby in the middle 5.3 GHz; 120 MHz [124] The average energy ratios of DMC are 20%, 42%, and 26% for theater, subway station, and lobby, respectively; The maximum power of DMC is distance-dependent and modeled by a linear regression model, Lognormal distributions is used to model the standard deviation (STD) of the maximum power of DMC Three indoor scenarios 11 GHz; -,…”

Wi-Fi Fine Time Measurement: Data Analysis and Processing for Indoor Localisation

“…Saito et al (2016) evaluated the multipath effect in the line-of-site (LOS) condition, distinguishing the directional and polarisation characteristics estimated by the RiMax algorithm proposed in Hanssens et al (2018). Mrstik et al (2007) quantitatively analysed the effect of angle of inclination between the Wi-Fi station and Wi-Fi AP in tracking using RADAR.…”

An Indoor Variance-Based Localization Technique Utilizing the UWB Estimation of Geometrical Propagation Parameters

“…In addition, the antenna array responses of transmitter and receiver will no longer be frequency-independent, and can vary significantly over the total UWB bandwidth. In order to track these frequency-dependent propagation parameters, an extension to the RiMAX framework was developed that can process UWB measurement data, and will be referred to as UWB-RiMAX from now on [21]. This framework is described in Algorithm 1, and depicted in Figure 4.…”