🧩 Planning a radio network in LTE technology Essay Example *️⃣ EssayHug

The main purpose of this document was to analyze radio signal propagation in LTE technology. For this analysis, we have simulated certain coverage predictions with the Atoll work platform. The propagation models used are: ITU529, Cost-Hata, and Standard Model. For the best results, the main parameters configured are sites, transmitters, and coverage predictions parameters.Following the simulations, it was found that the highest coverage area with the best signal, placing 10 sites, is given by the ITU529 model. Simulations have been made for urban, densely urban and suburban environments. The antenna types used are 65deg 18dBi, plus the tilt (0, 2 or 4) and the 2100 MHz frequency band. The simulated coverage predictions are the following: for the best signal level, transmitter coverage, maximum data transfer speed, effective signal level, signal quality.Keywords—LTE technology, coverage predictions, propagation models, sites, transmitters, parameters, urban, antenna types, signal level, RSRP, RSRQ.

I. INTRODUCTION

In this paper I synthesized the planning of an LTE network in accordance with the constraints mentioned for the best results. Radio signal propagation analysis was performed using the Atoll work environment. This platform is a very complex one because it gives us the possibility to simulate multiple coverage predictions using different propagation models.

II. STATE OF THE ART

The paper [1] introduces the Long Term Evolution (LTE), which is the main focus of this thesis. The main motivation and targets of LTE are explained, as well as the LTE radio related topics: e.g., the multiple access schemes used. Then, the LTE network architecture with each of the LTE entities and the protocols used in each are described in detail. This paper also provides other important chapters.The paper [2] presents the evolution and development of cellular networks for their planning and optimization for UMTS and LTE. The chapter is focused on the radio frequency (RF) planning and optimization of 4G LTE cellular networks.This book [4] describes the long term evolution (LTE) technology for mobile systems; a transition from third to fourth generation. Unlike other books, the authors have bridged the gap between theory and practice, thanks to hands on experience in the design, deployment, and performance of commercial 4G-LTE networks and terminals. The book is a practical guide for 4G networks designers, planners, and optimizers, as well as other readers with different levels of expertise.In this paper [6] is presented a simulation of LTE planning which include coverage by signal, overlapping zone, coverage by throughput in uplink and downlink and coverage by noise interference ratio in uplink and downlink. The paper [7] is the Atoll user manual. The Atoll working environment is both powerful and flexible. It provides a comprehensive and integrated set of tools and features that allow you to create and define your radio- planning project in a single application.In the paper [8] are presented the RSRP and RSRQ levels. In the LTE network, the UE must constantly measure the signal strength of its own cells and neighboring cells during idle mode, connected or handover mode to maintain the quality of the constant signal. UE measures RSRP and RSRQ in LTE. RSRP and RSRQ are essential measures of signal strength and quality for modern LTE networks.The main objective of the thesis [9] is to develop automatic planning tools based on Exact and approximate algorithms in order to solve the planning problem of 4G with high coverage and high Quality of Service.In the paper [10], a comparison is made between different proposed radio propagation models that would be used for LTE, like Stanford University Interim (SUI) model, Okumura model, Hata COST 231 model, COST Walfisch- Ikegami & Ericsson 9999 model. The comparison is made using different terrains e.g. urban, suburban and rural area.In the paper [11], some practical measurement results recorded from a live LTE network of Australia are analysed to verify the possible relationships among SINR, RSRP, RSSI and RSRQ as well as to evaluate the effects of SNR on throughput.

III. THEORETICAL FUNDAMENTALS

LTE is one of the newest releases of the 3rd Generation Partnership Project (3GPP) specifications.

A. The evolution of LTE

Via the use of bandwidths, advanced modulation and MIMO antenna schemes, LTE is able to provide data speeds in excess of 100 Mbps on the DL and 50 Mbps on the UL.With regard to spectrum efficiency, LTE is about three to four times better than HSDPA on the DL and two to three times better than HSUPA on the UL. This makes LTE a very attractive tool for network operators for better spectrum utilization.

B. LTE Network Architecture

The LTE system can be divided into two main branches: Evolved Universal Terrestrial Radio Access Network (E- UTRAN) and System Architecture Evolution (SAE). The E- UTRAN evolved from the UMTS radio access network; it is sometimes also referred to as LTE. The SAE supports the evolution of the packet core network, also known as Evolved Packet Core (EPC). The combination of both the E-UTRAN and the SAE compose the Evolved Packet System (EPS).

C. LTE Multiple Access Schemes

In LTE the multiple access transmission scheme is based on the Frequency Domain Multiplexing (FDM). Two different versions are used: Orthogonal Frequency Domain Multiple Access (OFDMA) for the downlink, and Single Carrier Frequency Domain Multiple Access (SCFDMA) for the uplink. OFDMA is a very efficient transmission scheme which is widely employed in many digital communication systems, e.g., Digital Video Broadcasting (DVB), WiMax, Wireless Local Area Network (WLAN). The reason behind the popularity of OFDMA comes from the fact that it has very robust characteristics against frequency selective channels. SC-FDMA is the transmission scheme in the LTE uplink. It provides a low peak-to-average ratio between the transmitted signal; it is a very desirable characteristic for the uplink to have an efficient usage of the power amplifier.

D. Duplexing in LTE

In LTE, time division duplexing (TDD) and frequency division duplexing (FDD) are supported. If the cellular system is using two different carrier frequencies for the UL and DL, then the duplexing is called FDD. In this case, both the UE and the eNB can transmit at the same time. For FDD, a channel separation is needed to reduce the interference between the UL and DL traffic. In TDD-based systems, the communication between theUE and the eNB is made in a simplex fashion, where one terminal is sending data and the other is receiving.

E. Radio Protocol Architecture of LTE

The E-UTRAN is composed of the eNB and the UE. The interface between the eNB and the UE is called the Uu interface. The radio protocol of LTE includes only the Uu interface. While control plane architecture is used to deliver and exchange signaling messages that are critical to manage UEs’ connectivity, user plane architecture is used to deliver and exchange data packets that are consumed by users or applications. The network nodes involved in the control plane are the UE, the eNB, and the MME.For the Uu interface, the control plane is composed of the Physical layer (PHY), the MAC layer, the RLC layer, the PDCP layer, and the RRC layer, and the user plane is composed of the Physical layer, the MAC layer, the RLC layer, and the PDCP layer.

F. Channel types in LTE

Data transport and signaling in LTE are transmitted by means of a protocol stack via the air interface using three different types of channel. LTE uses Logical, Transport and Physical channels; each type of channel is defined by its own set of functions and attributes.

G. Propagation models

Each propagation model available in Atoll is suited for certain conditions, frequencies and radio technologies. The table 1.1 summarises the frequency band, necessary geo data, recommended use of each propagation model used in this work.