2. Introduction 4. Results and Discussion

7th International Conference on Internet Technologies & Applications

5th International Workshop on Energy Efficient and Reconfigurable Transceivers (EERT): Towards Green 5G & Internet of Everything

Ali A. AlAbdullah1, Nazar Ali2, Huthaifa Obeidat1, Raed A. Abd-Alhmeed1 and Steven Jones1 1School

of Engineering and Informatics, University of Bradford, Bradford, BD7 1DP, UK, [email protected], [email protected]. 2ECE Dept., Khalifa University, Abu Dhabi, UAE

1. Aims and Objectives The aims of this study are to;  Present the mmWave indoor propagation characteristics including path loss models and multipath delay spread values for systems using directional and omnidirectional antennas.  Investigate the performance of the four 5G candidate frequencies, 28 GHz, 39 GHz, 60 GHz and 73 GHz, in line-of-sight (LOS) and non-line-of-sight (NLOS) scenarios.

3. Simulation Setup The site to be explored is the third floor in Chesham building at the University of Bradford, U.K. The floor plan was first loaded into the ray tracing Wireless InSite software. The layout of the floor plan is shown in Fig. 1 where the transmitter is located in Lab (B3.26) and the measurements are conducted in three NLOS paths (routes) and one grid of LOS receivers.

 Comparisons are made against simulation data obtained from the 3D Ray Tracing Wireless InSite software over TxRx separations of 1.5 m to 62 m.  Study the effect of the frequency-dependent electrical properties, such as conductivity-σ and permittivity-ε, of common building materials on the propagation behavior of mmWaves due to reflections, diffractions and penetrations of walls and objects (obstacles).

The increasing numbers of sophisticated electronic devices and applications requiring access to telecommunication and internet infrastructures, demand robust and very high bandwidth wireless connectivity [1]. Researchers have been looking to higher frequencies, 20-90 GHz, as potential solutions [2]. The applications of mmWaves are mainly used in indoor environments, small cells and backhaul links. Inspired by [3], in this paper we will explore the behaviour of the propagation channel at four frequencies: 28, 39, 60 and 73 GHz using the certified and trustworthy Ray-Tracing software. In this work, the effect of building materials has been incorporated along with measurements from [3] to produce a more accurate channel model. The simulated environment is similar to one in [4], which included corridors, offices and laboratories with furniture. It is worth to mention that the environment, frequencies and scenario in this work, have been chosen to be applied as a more realistic mmWave channel model to assess the system performance in [5].

Properties of Transmitter and Receiver Antennas

Gain (dBi) E-plane Half Power Bandwidth (degree) Polarization Waveform Input Power (dBm) Temperature (K) VSWR Receiver Threshold (dBm) Height (m)

The delay spread is a valuable measure of an assortment of multipath related impacts. It can be ascertained utilizing the assumption of unlimited bandwidth, as part of which the energy of every ray path lands at a single moment in time [7]: 𝑃𝑃 2 ∑𝑁𝑁 𝑖𝑖=1 𝑃𝑃𝑖𝑖 𝜏𝜏𝑖𝑖

𝑃𝑃𝑅𝑅

− 𝜏𝜏

2

Fig 6: The Received Power vs. Receiver Positions of each receiver point to transmitter point for different frequencies and (a) Route-1, (b) Route-2, (c) Route-3 and (d) Grid-1..

(2) Fig 3: Delay Spread vs. Tx-Rx Separation distance for different frequencies and (a) Route-1, (b) Route-2, (c) Route-3 and (d) Grid-1.

Fig. 1: Floor layout of 3rd Floor, University of Bradford, with simulation routes.

2. Introduction

Properties

The received power is limited between -100 and -150 dBm over the route 2 and route 3, which is represent the worst case, While in route 1 it was between 80 and -140 dB with wider range reaching up to 45 m.

Delay Spread (𝜎𝜎𝜏𝜏):

𝜎𝜎𝜏𝜏 =

 Find the relationship between the received power, delay spread, number of ray paths and frequency.

Received Power

Transmitter Antenna Horn

Receiver Antenna Omnidirectional

17.8 10

1.80 90.00

Vertical Sinusoid 30.0 293.00 1.00 -140.00

Vertical Sinusoid 293.00 1.00 -140.00

2.5

1

Representative material electrical properties are calculated and listed in Table 2. The real part of the relative permittivity, 𝜖𝜖', and conductivity, 𝜎𝜎, are compiled using the curvefitting approach and simple expressions derived in [8]. Table 2: Materials Parameter Values at Different Frequencies:

Materials Concrete Wood Glass Ceiling board Metal Floorboard Brick Chipboard Plasterboard Vacuum

73GHz σ Re(ᵋr) 1.051 5.310 0.467 1.990 0.717 6.270 0.074 1.500 10e7 1.000 1.451 3.660 0.038 3.750 0.616 2.580 0.242 2.940 0.000 1.000

60GHz σ Re(ᵋr) 0.897 5.310 0.378 1.990 0.567 6.270 0.059 1.500 10e7 1.000 1.1133 3.660 0.038 3.750 0.5290 2.5800 0.210 2.940 0.000 1.000

39GHz σ Re(ᵋr) 0.633 5.310 0.239 1.990 0.340 6.270 0.036 1.500 10e7 1.000 0.622 3.660 0.038 3.750 0.378 2.580 0.155 2.940 0.000 1.000

28GHz σ Re(ᵋr) 0.484 5.310 0.167 1.990 0.229 6.270 0.024 1.500 10e7 1.000 0.398 3.660 0.038 3.750 0.292 2.580 0.123 2.940 0.000 1.000

4. Results and Discussion The system mentioned in the previous section was simulated using Wireless InSite. Fig. 2 shows the rays radiating from the transmitter to many different positions over the scenario field. The number of rays is calculated by the simulator. It is clear from the ray tracing in Fig. 2 that the highest rate of signal penetration is through glass and then plaster board, regardless of wall thickness. However, NLOS signals suffer greatly when concrete and wooden walls.

Fig. 2: Ray Trace for different routes at 60GHz.

Path Loss Characteristics It has been found by the channel characterization in [6] that the non-line-of-sight (NLOS) channel experiences higher attenuation than the line-of-sight (LOS) channel. The large scale fading F(d) can be expressed as [6];

𝐹𝐹 𝑑𝑑

= 𝑃𝑃𝑃𝑃 𝑑𝑑𝑜𝑜 + 10𝑛𝑛 log Where

𝑃𝑃𝑃𝑃 𝑑𝑑𝑜𝑜 = 20 log

𝑑𝑑 −Sσ 𝑑𝑑𝑜𝑜 4𝜋𝜋𝑑𝑑𝑜𝑜 𝜆𝜆

(2)

(3)

Fig 4: The Path Loss vs. 3D Tx-Rx Separation distance for different frequencies and (a) Route-1, (b) Route-2, (c) Route-3 and (d) Grid-1.

5. CONCLUSIONS The characteristics of various indoor channels are investigated under four potential mm-Wave frequencies. The effect of common building materials on the properties of propagating signals has been presented including direction of arrival and multipath effects. It has been noted that the path loss behaves as expected at high frequencies and large number of barriers. Concrete and wood Walls have a much serious effect on signals than plaster board and glass walls. In contrast, delay spread, number of multipath received and power are decreased in NLOS environment as a results of the nature of these frequencies. Signal penetration rate of wood is very low, and almost non-existent for Concrete compared with other material type such as plasterboard. In addition, the change in thickness of walls have a relatively little effect on signal propagation in general. This study should be considered in the design of modern buildings, smart cities and in the selection of building materials for mmWave indoor applications such as 5G mobile telecommunications.

References [1] Maccartney, George R., Theodore S. Rappaport, Shu Sun, and Sijia Deng. "Indoor office wideband millimeter-wave propagation measurements and channel models at 28 and 73 GHz for ultra-dense 5G wireless networks." IEEE Access 3 (2015): 2388-2424. [2] Samimi, Mathew K., and Theodore S. Rappaport. "Local multipath model parameters for generating 5G millimeter-wave 3GPP-like channel impulse response." 2016 10th European Conference on Antennas and Propagation (EuCAP). IEEE, 2016. [3] Steve Methley, William Webb, Stuart Walker and John Parker, “5G Candidate Band Study, Study on the Suitability of Potential Candidate Frequency Bands above 6GHz for Future 5G Mobile Broadband Systems”, Final Report to Of com, March 2015. [4] T. S. Rappaport, G. R. MacCartney, M. K. Samimi and S. Sun, "Wideband Millimeter-Wave Propagation Measurements and Channel Models for Future Wireless Communication System Design" in IEEE Transactions on Communications, vol. 63, no. 9, pp. 3029-3056, Sept. 2015. [5] Anoh, Kelvin, Godfrey Okorafor, Bamidele Adebisi, Ali Alabdullah, Steve Jones, and Raed Abd-Alhameed. "Full-Diversity QO-STBC Technique for Large-Antenna MIMO Systems." Electronics 6, no. 2 (2017): 37.

Number of Signal Paths  The maximum number of paths used in the calculation is set to 10.  In many cases, like route-1 and the grid, this number can be attained easily as shown in the figure.  The number of paths usually affect the received signal strength depending on whether they are added constructively or destructively.

Fig 5: The Number of Bath vs. Receiver Positions of each receiver point to transmitter point for different frequencies and (a) Route-1, (b) Route-2, (c) Route-3 and (d) Grid-1.

[6] S. Geng, J. Kivinen, X. Zhao, and P. Vainikainen, “Millimeter-wave propagation channel characterization for short-range wireless communi-cations,” IEEE Trans. Veh. Tech., vol. 58, no. 1, pp. 3–13, Jan. 2009. [7] “Wireless InSite, Reference Manual”, Version 2.6.3, Remcom Inc., 315 S. Allen St., Suite 416 State College, PA 16801, November 2012., Jan. 2009. [8] “Effects of building materials and structures on radio wave propagation above about 100 MHz” Recommendation ITU-R P.2040-1 (07/2015).