International Journal of Electrical, Electronics and Computers (EEC Journal) [Vol-2, Issue-3, May-Jun 2017] https://dx.doi.org/10.24001/eec.2.3.3 ISSN: 2456-2319 Third Generation Wireless Modeling in Urban Environment Kusay F. Al-Tabatabaie
Computer Science Dep., Cihan University –Sulaimanyia Campus, Iraq
Abstract—The global mobile communication is fast coverage areas with varied terrain characteristics [6]. For growing in industry. This paper recommends appropriate clear line of sight (LOS) propagation, the range between settings to evaluate the performance of wireless mobile the transmitter and receiver is determined by the free system deploying third generation networks in an urban space path loss (PL) equation [7], can be derived from the environment. To meet this aim, a case Study of following expression (1) Sulaimanyia city is considered for this study by 4d PL 20log dB (1) establishing suitable radio channel models. The work 10 presents a statistical channel model, where fixed and nomadic analysis services are considered in the simulated where d and λ are the range and wavelength in meters, radio coverage scenario. The cartographic dataset had respectively. been collected, and Matlab Software was used for In Non-Line-of-Sight (NLOS) cases, the performance of showing the analysis and simulation results. Statistical higher frequencies is worse with reliable distances channel models are derived that combine standard dropping even faster. Most paths are obstructed by parameters such as separation distance, operating objects and buildings. When penetrating obstacles, radio frequency and terminal height with more advanced and waves are decrease in amplitude. As the radio frequency innovative parameters such as distance dependent increases, the rate of attenuation increases. Fig. 1 shadowing and LOS probability. illustrates the effect of higher frequencies having higher Keywords— Mobile, 3G, Sulaimanyia City, propagation attenuation on penetrating obstacles [8]. Model, ICS telecom cartography.
I. INTRODUCTION The rapid revolution of wireless technologies in the past decade has led to the fast adoption of smart phones. Consumers are expecting every device they have to be connected to the network to record, transfer, view, or monitor data [1]. Therefore, as wireless technologies are Fig.1: Higher frequencies have higher attenuation on evolving, so must radio planning methods. Many penetrating obstacles. researchers worked to progress cellular solutions such as A radio beam can diffract when it hits the edge of an reducing transmit power, improving coverage, and object. The angle of diffraction is higher as the frequency provide high capacity connectivity [2-5]. The need to decreases. When a radio signal is reflected, some of the evaluate the performance of such systems in an urban RF power is absorbed by the obstacle, attenuating the environment is required for proper study to set radio strength of the reflected signal. Fig. 2 show that higher channel model. frequencies lose more signal strength on reflection [9]. To determine the radio coverage is required to take into account the network type (Fixed, nomadic, mobile…) and target type (Major metropolitan areas or wireless complement connection for rural areas). This call radio signal path loss, which increases with increasing frequency. The radio frequency (RF) power of radio signals would be reduced when radio signals have travelled over a considerable distance. Therefore, in most cases, the systems with higher frequencies will not Fig.2: Frequency dependence of signal strength on operate reliably over the distances required for the reflection www.eecjournal.com Page | 17 International Journal of Electrical, Electronics and Computers (EEC Journal) [Vol-2, Issue-3, May-Jun 2017] https://dx.doi.org/10.24001/eec.2.3.3 ISSN: 2456-2319 Conversely, high frequency is required to provide II. RADIO PROPAGATION MODEL sufficient bandwidth. However, spectrum allocation A radio propagation model is an empirical mathematical widths are normally proportional to the frequency of the formulation for the characterization of radio wave band and hence nominating the 3400-4200 MHz band for propagation as a function of frequency, distance and other IMT-Advanced would allow the spectrum users to operate characteristics. A single model is usually developed to with more and wider channels [10]. The use of higher predict the behaviour of propagation for every similar link available capacity can also support much higher data rates under similar constraints. The essential aim of signal than the lower spectrum. In addition, higher frequency propagation studies is to formalize how the signal can can reduce the financial cost of licensing. It is important propagate from one point to another. Only in such to notice that gain of antennas is a functional to the situation can a typical model predict the path loss effect frequency being received [11]. In free space propagation, on an area covered by a single or multi transmitter (s) clear and unobstructed line-of-sight (LOS) path is [13]. available and the first Fresnel zone is maintained between It is found that ITU-R P.452-14 [14] is the most suitable base station and terminal. Free space path loss can be propagation model for this study, because it can cover obtained by using the logarithmic value of the ratio from 0.7 MHz to 30 GHz frequency range. The between the receiving and transmitting power as prediction of the line of sight LOS is a result of the signal expressed in Equations 2, 3, 4 and 5. This simplified free after being exposed to the path and clutter loss model space path loss model for unity antenna gain is based on CEPT and ITU organizations have accepted a common [12]. Equations 3, 4 and 5 indicate that free space path formula for wireless transmission assessment at a loss is frequency dependent and it increases with distance. microwave frequency level. This formula has The increase of distance and frequency produce similar incorporated the clutter attenuation as well as effect on the path loss. environmental effects, and is expressed as follows: P PL 10log r (2) dB 10 L(d) 92.44 20logd 20log f A (6) Pt km GHz h
PL 147.56 20log f 20log d (3) dB 10 Hz 10 m Where d (km) is the distance between interferer and
PLdB 32.44 20log10 fMHz 20log10 dKm (4) victim FSS receiver, f is the carrier frequency in GHz and Ah is loss due to protection from local clutter (i.e clutter PL 92.44 20log f 20log d (5) dB 10 GHz 10 Km loss), and is given by: Where f is frequency, d is distance; Pr and Pt are the receiving and transmitting power in watts, respectively. dk h Ah 10.25e 1 tanh6 0.625 0.33 (7) Fig. 3 shows simulation for free space path loss for the h a frequencies 900 MHz, 2000 MHz, and 4000 MHz at where dk (km) is the distance from nominal clutter point different transmitter - receiver distances. to the antenna, h is the antenna height (m) above local ground level and ha (m) is the nominal clutter height above local ground level. In [14], clutter losses are evaluated for different categories, such as trees, rural, suburban, urban and dense urban. Increasing antenna height up to the clutter height will result in a decrease in clutter loss, as shown in Table 1 and Fig. 4.
Table.1: Nominal clutter heights and distances [14] Clutter Clutter Height Nominal Category ha (m) Distance dK (km) Rural 4 0.1 Suburban 9 0.025 Urban 20 0.02 Dense urban 25 0.02 Fig.3: Free space path loss at 900 MHz, 2000 MHz, and 4000 MHz Where table 1 reveals that the value of nominal distance is highest for rural and suburban areas, whereas for urban
www.eecjournal.com Page | 18 International Journal of Electrical, Electronics and Computers (EEC Journal) [Vol-2, Issue-3, May-Jun 2017] https://dx.doi.org/10.24001/eec.2.3.3 ISSN: 2456-2319 and dense urban areas the separation distance decreases in channel bandwidth of the colour TV is 6 MHz in America response to the clutter loss increment. and Japan, 7-8 MHz in Europe. Digital television is incompatible with analogue TV in terms of how the broadcasted information is represented as a signal. However, it must have RF spectrum compatibility. An important factor in defining the digital standard is to consider the channel bandwidth of existing analogue standards (or smaller bandwidth). Countries currently using Phase Alternation by Line (PAL) or Sequential Colour with Memory (SECAM) with an 8 MHz UHF bandwidth are likely to choose only a standard that can handle such channels Digital Video Broadcasting– Terrestrial (DVB-T). On the other hand, countries using National Television System Committee (NTSC) or PAL with 6 MHz bandwidth may choose any of the standards, while maintaining the bandwidth compatibility [17].
V. SIMULATION RESULTS AND ANALYSIS Fig.4: Clutter losses for rural, suburban, urban and In order to influence the choice of the propagation model, dense urban areas. the urban radio planning had been performed for the cartographic dataset. However, the most important thing III. POINT-TO-MULTIPOINT (P-MP) is the technology which applied to simulate the channel Similarly, a Point-to-Multipoint fixed service is one that model in this urban environment. This technology involves a base station and a number of remote stations as depends on the technical characteristics and the type of shown in Fig. 5. applied engineering methodology such as fixed-type, mobile-type, using OFDM or not. In this work, a wide range of wireless technologies for urban areas were considered, a combination from both of mature 3G and WLL technologies had been performed to sketch the quality of service (QoS) as shown in fig. 6.
Fig.5: Point-to-Multipoint FWA Service.
In a P-MP service, the base station sends a broadcast to the remote stations in the downstream direction and receives transmissions from the remote stations in the upstream direction. A sectored antenna [15, 16] is usually employed within P-MP service as in LMDS and Microwave Multipoint Distribution Service (MMDS) Fig.6: QoS to each sector in Sulaimanyia area services.
The overall (QoS) to each sector can be calculated IV. BROADCASTING SERVICES according to: The broadcasting service consists of sound, video and A service flow provisioning defined on a per data broadcasting. Video broadcasting is a P-MP TV mobile unit basis. transmission for public reception, typically from a fixed emitter to fixed and portable receivers using the The throughput available at each sector, horizontal frequency (line repetition frequency). The calculated according to the OFDMA permutation www.eecjournal.com Page | 19 International Journal of Electrical, Electronics and Computers (EEC Journal) [Vol-2, Issue-3, May-Jun 2017] https://dx.doi.org/10.24001/eec.2.3.3 ISSN: 2456-2319 and the number of data sub-carriers used, the UL/DL duration ratio, the modulation… A variation of the contention ratio according to the hour of the day. The indoor propagation loss due to building absorption can be simulated by applying a diffusion coefficient per building type. To activate set allocation, radio-planner had been specify for each selected base station (BS), the active sets each BS in prediction tool, ICS telecom tool had been used as shown in fig. 7. where ICS Telecom is able to model both Inter channel Interference (ICI) and Inter Symbol Interference (ISI).
Fig.8: Display of the FSBB hand-over of a mobile unit anchored to active set 3
VI. CONCLUSION The proposed channel propagation model had been presented using using ICS telecom cartography, where cartographic dataset type used to show streets, the buildings locations and heights outlined. For coverage calculations, the empirical or deterministic propagation model had been chosen using High Resolution datasets. This project novelty is to improves the accuracy of peer- to-peer channel power prediction in urban environments by using more advanced distance dependent shadowing, LOS probability. And provides solution to the problem of radio channel modelling in system level simulations that incorporate multi-hop/ad-hoc and fixed relay network elements in an urban environment in the 2-5 GHz range.
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