On the Validation of Path Loss Models Based on Field Measurements Using 800 MHz LTE Network Yazan A Alqudah, Belal Sababha King Abdallah II School of Engineering Princess Sumaya University for Technology Amman, Jordan Abstract— Path loss models play an important role in cellular network planning and deployment. This work reports on the path loss models accuracy for predicting received signal strength in an urban environment. The path loss is a key factor in coverage analysis and hence model tuning is mandatory for accurate RF planning. Using a large set of field measurements from a commercial LTE 800MHz network with 15MHz channel bandwidth, different propagation models are evaluated and compared for their accuracy in predicting the path loss. The measurements are conducted in Dubai, UAE which offers a unique environment in its construction materials, architecture, topology and vegetation. The goal of sharing our findings is to help improve the accuracy of the models used to depict path loss. Keywords— Mobile LTE, Path Loss, Propagation Models

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I. INTRODUCTION

TE is the latest evolution in cellular data services. The technology is based on a 3GPP Release 10 standard. LTE offers high data rates, with downlink and uplink speeds up 150 Mbps, and 50 Mbps, respectively for category 4 (CAT4) terminals with 20MHz channel bandwidth. LTE offers high spectral efficiency and scalable bandwidths from 1 MHz to 20 MHz. It supports both Frequency Division Duplexing (FDD) and Time Division Duplexing (TDD) [1]. Network operators, vendors and smartphone manufacturers were quick to adopt the new technology. In 2015, it is estimated that there are over 400 commercial LTE networks in more than 140 countries [2]. LTE standards support different carrier frequencies. The deployed carrier frequency varies by the region. The main deployed frequencies deployment includes 800, 1800 and 2600 MHz. In this study, we conducted model tuning for LTE at 800MHz with a 15MHz bandwidth. The commercial LTE network has another layer of LTE1800MHz with 20MHz channel bandwidth for capacity boosting at selected areas, while the 800MHz provide nationwide coverage. The 800MHz carrier provided extended coverage and better indoor penetration compared to 1800MHz which is used as a capacity layer. 3GPP release 10 introduced CAT6 with LTE1800MHz (20MHz) + LTE800MHz (10MHz) aggregated for peak TP of 225Mbps. Therefore, for this specific scenario, if carrier aggregation is introduced by CAT6, then only 20MHz + 10MHz can be aggregated to engender 225MHz peak throughput.

Ayman Elnashar, Sohaib H. Sababha Emirates Integrated Telecommunications Company Dubai, UAE

Irrespective of carrier frequency, network operators rely on RF power analysis and measurements during network planning, deployment and post deployment optimization. Propagation and path loss models are used to predict the coverage and ensure quality of service. Path loss models can be classified as empirical (stochastic) or deterministic. Empirical models rely on measured data. Hata Okumura and COST 231 are examples of empirical models for the macro cellular environment. Deterministic models predict path loss based on physical laws governing electromagnetic wave propagation. Whie deterministic models are more accurate, they require involved computations and an accurate description of the environment and its objects A significant amount of research has focused on path loss using different carrier frequencies and operating environments. In [3], measurements were compared against empirical propagation models. The results show closest agreement with ECC-33 model for 3.5 GHz. The parameters of Okumura-Hata model were tuned based on field measurement for urban and suburban environments operating at 140 and 440MHz [4]. Propagation models were studied utilizing WiMAX networks operating at 3.5 GHz based on field measurement in [5]-[10]. In [11], path loss was analyzed for GSM network operating at 900 MHz and experimental data was used to tune Hata model. In this paper, we analyze the path loss of a commercial LTE network at 800 MHz based on field measurements. The existing path loss models are evaluated for path loss prediction. Moreover, a new model is proposed for LTE at 800MHz and compared with the existing models. The paper is organized as follows: Section II reviews the propagation models. Section III discusses the methodology used to take the measurements. Section IV provides the results of the field measurements. Finally, Section V concludes the paper.

II. PROPAGATION MODELS Path loss results from the environment interaction as a radio wave propagates between the transmitter and receiver. Path loss is defined as the difference between the transmitted and received power. Path loss models are proposed to predict signal power based on deployment. The models dependencies on distance separation between transmitter and receiver, operating frequency, transmitter and receiver antennas’ height and environment specific dependency. Several models are available to predict path loss. These models have been traditionally applied to frequencies below 2 GHz [1217]. The models are summarized in Table I. The free space (FS) path loss is an analytical model that predicts the strength of the signal received when a clear line of sight path exists between the transmitter and the receiver. The FS model does not account for multipath propagation and cannot be used for pointmultipoint radio link. However, it is included for reference. The Stanford University Interim (SUI) is an empirical model recommended by standardizing committee [13]. The constants and equations for the models are given in Table I. The model contains frequency and height correction factors. The ECC-33 also known as Hata-Okumura extended model is based on Okumura model [16][17]. The COST-231 Hata model is an extension to the Hata-Okumura model that has a correction factor for the environment. The Hata-Okumura model was developed for 500-1550 MHz. The Cost-231 model extends Okumura-Hata model to a frequency range up to 2 GHz [13]. The model calculates path loss for urban, suburban and rural areas. The Ericsson model is based on a modified OkumuraHata model and allows changing parameters based on the environment. Standard propagation model (SPM) is another form of Cost231-Hata model which has been adopted in several RF planning tools. The standard propagation model (SPM) is based on empirical formulas and a set of parameters that are set to their default values. SPM is a model (deduced from the Hata formula) particularly suitable for predication in the 150MHz~3500MHz band over long distance (1Km