Enhanced TOA Estimation Using OFDM over Wide-Band Transmission Based on a Simulated Model

Huthaifa A Obeidat,Mohammad R Rawashdeh,Ali A Abdullah,Omar A Obeidat,Wafa S Shuaieb,Raed A Abdallhameed,Imran Ahmad

doi:10.1007/s11277-021-09297-z

Abstract

This paper presents the advantages of using a wideband spectrum adopting multi-carrier to improve targets localization within a simulated indoor environment using the Time of Arrival (TOA) technique. The study investigates the effect of using various spectrum bandwidths and a different number of carriers on localization accuracy. Also, the paper considers the influence of the transmitters’ positions in line-of-sight (LOS) and non-LOS propagation scenarios. It was found that the accuracy of the proposed method depends on the number of sub-carriers, the allocated bandwidth (BW), and the number of access points (AP). In the case of using large BW with a large number of subcarriers, the algorithm was effective to reduce localization errors compared to the conventional TOA technique. The performance degrades and becomes similar to the conventional TOA technique while using a small BW and a low number of subcarriers.

Highlights

Orthogonal Frequency Division Multiplexing (OFDM) has emerged in recent years as an effective digital modulation technique that is at the heart of all major wireless standards used or in development today, such as the 4G Long-Term Evolution (LTE), Wi-Fi IEEE 802.11a, WiMAX and in Digital Video Broadcasting (DVB) systems [1,2,3].OFDM is utilized in several communication systems due to its robustness to multipath channels and high transmission rate in wireless communications networks
This paper introduces a coded OFDM system to be used in the application of localization systems and enhance the Time of Arrival (TOA) estimation over the wideband transmission
This paper describes the OFDM technique for wireless communications and desirous advantages of OFDM to improve the localization of targets, in order to provide accurate mobile station (MS) positioning within indoor environments, and provided an overview of different delimiting factors that affect the performance and capability of OFDM

Summary

Introduction

Orthogonal Frequency Division Multiplexing (OFDM) has emerged in recent years as an effective digital modulation technique that is at the heart of all major wireless standards used or in development today, such as the 4G Long-Term Evolution (LTE), Wi-Fi IEEE 802.11a, WiMAX and in Digital Video Broadcasting (DVB) systems [1,2,3]. Reliable signal transmission, the OFDM technique requires precise timing and accurate frequency synchronization [4, 5]. Authors in [10] used the OFDM-Time of Arrival (TOA) algorithm for position estimation of a Long Term Evolution (LTE) signal. This paper introduces a coded OFDM system to be used in the application of localization systems and enhance the TOA estimation over the wideband transmission. A fractional spectrum of the lower Ultra-Wideband (UWB) was utilized to mitigate the effects of indoor channel propagations due to the high number of multipath, in which several carriers are spread over the bandwidth based on the impulse response of the channels using Wireless-InSite (WI) and suitable estimations of time arrivals are applied, followed by a numerical technique to estimate the position of the hidden objects.

Mathematical Model of OFDM for Time of Arrival Estimation

Simulation Model

Results and Discussion

Conclusions