UWB channel characterization in 28 ghz millimeter waveband for 5G cellular networks

The demands of high data rate transmission for future wireless communication technologies are increasing rapidly. The current bands for cellular network will not be able to satisfy these requirements. The millimeter wave (mm-wave) bands are the candidate bands for the future cellular networks. The 28 GHz band is the strongest candidate for 5G cellular networks. The large bandwidth at this band is one of the main parameters that make the mm-wave bands promising candidate for the future cellular networks. To know the wideband channel behavior in mm-wave bands, the wideband channel characterizations are required. In this paper, the 3D WINNER model is used to model the wideband channel at 28 GHz band. Based on this model, the time dispersion parameters at 28 GHz mm-wave band are investigated. The root mean square delay spread and the mean excess delay are the main parameters that can be used to characterize the wideband channel. Morever, the cumulative distribution function (CDF) is used to model the RMS delay spreads. The results show that the RMS delay spread varies between 4.1 ns and 443.7 ns

Adaptive spatial mode of space-time and spacefrequency OFDM system over fading channels

In this paper we present a 2 transmit 1 receive (1 Tx : 1 Rx) adaptive spatial mode (ASM) of space-time (ST) and space-frequency (SF) orthogonal frequency division multiplexing (OFDM). At low signal to noise ratio (SNR) we employ ST-OFDM and switch to SF-OFDM at a certain SNR threshold. We determine this threshold from the intersection of individual performance curves. Results show a gain of 9 dB (at a bit error rate of 10-3) is achieved by employing adaptive spatial mode compared to a fixed ST-OFDM, almost 6 dB to fixed SF-OFDM, 4 dB to Coded ST-OFDM and 2 dB to a fixed coded SF-OFDM, at a delay spread of 700 ns

Impedance Mathing Improvement of Half-Cut Broadband Printed Monopole Antenna with Microstrip Feeding

The requirement of wireless access networks and user equipments to support coexistence of many communication standards and frequency bands poses challenge on antenna to be broadband and small. The application of half-cut technique to broadband printed monopole with microstrip feeding worsens the resulted antenna’s impedance. To improve the half-cut antenna impedance mathing, two methods were investigated in this paper: (1) monopole and ground extension, (2) the application of microstrip line transformer and ground extension. The first approach only produces limited improvement, whereas method #2 can enhance the return loss significantly. The application of the second approach potentially produces antenna pair that has low mutual coupling, good return loss, and small size. Considering its radiation pattern, the antenna is suitable for diversity and MIMO. Its application in broadband microwave-photonic access point need special arrangement due to radiation null at 5 GHz band at right side.DOI:http://dx.doi.org/10.11591/ijece.v3i5.337

Propagation Path Loss Modeling and Outdoor Coverage Measurements Review in Millimeter Wave Bands for 5G Cellular Communications

The global bandwidth inadequacy facing wireless carriers has motivated the exploration of the underutilized millimeter wave (mm-wave) frequency spectrum for future broadband cellular communication networks, and mmWave band is one of the promising candidates due to wide spectrum. This paper presents propagation path loss and outdoor coverage and link budget measurements for frequencies above 6 GHz (mm-wave bands) using directional horn antennas at the transmitter and omnidirectional antennas at the receiver. This work presents measurements showing the propagation time delay spread and path loss as a function of separation distance for different frequencies and antenna pointing angles for many types of real-world environments. The data presented here show that at 28 GHz, 38 GHz and 60 GHz, unobstructed Line of Site (LOS) channels obey free space propagation path loss while non-LOS (NLOS) channels have large multipath delay spreads and can utilize many different pointing angles to provide propagation links. At 60 GHz, there is more path loss and smaller delay spreads. Power delay profiles PDPs were measured at every individual pointing angle for each TX and RX location, and integrating each of the PDPs to obtain received power as a function of pointing angle. The result shows that the mean RMS delay spread varies between 7.2 ns and 74.4 ns for 60 GHz and 28 GHz respectively in NLOS scenario

Channel fading attenuation based on rainfall rate for future 5G wireless communication system over 38-GHz

In this paper, the effect of heavy rainfall on the propagation of a 38-GHz in a tropical region was studied and analyzed. Real measurement was collected, with a path length of 300 meters, for a (5G) radio linkage in Malaysia, installed at the Universiti Teknologi Malaysia (UTM) Johor Bahru campus. The employed system entails an Ericsson MINI-Link 38 E-0.6 mm, with a horizontal polarization (HP) antenna at the top integrated with a rain gauge and a data logger. Daily registered samples with a single minute span, for a full study period of 1 month, were collected and evaluated. The obtained rain rate was found as 56 mm/hr with a specific rain attenuation of 18.4 dB/km for 0.01% of the time. In addition to that, a calculated average rain attenuation of 5.5 dB for the transmission path of 300 meters length, was calculated. Based on these findings, a recommendation to update the International Telecommunication Union (ITU) specification of the rain attenuation for Malaysia is proposed. Based on the results, we suggest shifting the zone classification of Malaysia from zone P to zone N-P. Therefore, accurate design for future 5G systems would rely on more precise estimated attenuation levels leading to enhanced performance

The Feasibility of Coexistence Between 5G and Existing Services in the IMT-2020 Candidate Bands in Malaysia

In 2015, the international telecommunication union (ITU) proposed 11 candidate millimeter-wave bands between 24 and 86 GHz for the deployment of future fifth mobile generation (5G) broadband systems. Furthermore, the ITU called for spectrum-sharing studies in these bands. Since 5G specifications are not yet defined, the utilization of radio spectrum by 5G mobile systems will assist in identifying these specifications. This paper introduces Malaysia as a case study for the deployment of 5G systems. This includes a discussion of the current status of the Malaysian telecommunication market. Then, we investigate the current services that are already deployed in the proposed bands. Our investigation shows that the fixed (F) service is the most deployed as a primary service in the candidate bands. For this reason, a preliminary spectrum-sharing study is conducted on the basis of a modified 5G spectrum-sharing model to evaluate the feasibility of coexistence between 5G and F services in the 28-GHz band. Our modified methodology can be used for spectrum-sharing studies between 5G and any other services for an initial spectrum-sharing investigation. The results show that the F service will be severely affected by the 5G system transition in the 28-GHz band, especially in the base station (BS)-to-BS sharing scenario. The best band from the perspective of current spectrum allocation for 5G systems is the 45-GHz (i.e., 45.5-47 GHz) band, since it is already reserved for mobile service for primary allocation and not utilized. This paper is carried out concurrently with current worldwide efforts investigating spectrum sharing, as requested by the ITU in agenda item 1.13 for the next world radio conference 2019

A novel green antenna phase-shift system with data acquisition boards

A novel green phase shifter system is proposed in this research. The system is developed by a combination of reconfigurable beam steering antennas and data acquisition (DAQ) boards. A combination of two reconfigurable beam steering antennas, located side-by-side, forms a spatial configuration structure with a fabricated ‘green’ element plank of rice husk placed in between. The concept of a spatial configuration technique has been ‘mutated’ by shifting the structure of spiral feed line and aperture slots of first beam steering antenna by as much as 45 ◦ . The PIN diode switches connected to the DAQ boards enable the intelligent capability of the spatial antennas. The activation of certain degree radiation patterns of either the first beam steering antenna or the second beam steering antenna depends on the memory of the DAQ boards — Beam Manager. When an intruder comes from the cardinal angles of 0◦/ 360◦, 90◦, 180◦, or 270◦, its range and angles’ location will be automatically detected by the first antenna through the output ports of the 1st DAQ: P1.0, P1.1, P1.2, and P1.3. The second antenna is then activated by the output ports of the 2nd DAQ: P2.0 up to P2.3, to adaptively maneuver the beam towards four different ordinal directions of 45◦, 135◦, 225◦, and 315◦

Spectrum investigation for sharing analysis between BWA system and FSS receiver

In this research, testing the compatibility between Fixed Broadband Wireless Access (BWA) as a case study for the International Mobile Telecommunication (IMT-Advanced) and Fixed Satellite Services (FSS) networks in 3400-4200MHz range (C-band) has been studied and discussed in details. The interference between Fixed Satellite Service earth station(FSS ES) and Broadband Wireless Access(BWA) is considered and the aim of the article is to avoid interference between FSS ES and BWA by using minimum separation distance. Possibility of coexistence and sharing analysis were obtained by taking into account the detailed calculations of the most useful formulas for path loss effect and clutter loss by using the existing parameters of FSS and the BWA base station parameters located in the wireless communication center, Universiti Teknologi Malaysia (UTM). In-band interference has been concluded, analyzed and simulated (using Matlab) for several environments (rural, suburban, urban and densurban) in response to different clutter altitude. Channel prediction for two scenarios (rural and suburban) as a trail map was delineated by ATDI software. Simulation results indicate that the proposed mitigation scheme is highly efficient in terms of reducing the separation distances. Comparing the measurements with simulated result has also been done with high percentage of accuracy to show the amount of closeness or similarity between both results

Switched Beam Smart Antenna for Wireless Local Area Network

In wireless communication system, interference is one of the issue facing that can disturb in communicating between base station and mobile devices. This paper propose switched beam smart antenna system, an octagonal configuration of directional antenna is introduced and selecting beam to desire user. Each beam of antenna covered 45 degrees; by assembly of all directional antennas to create an omni-directional configuration with coverage all the beam 360 degrees. To control of the beam switching, an inexpensive microcontroller PIC 16F877 from microchip used, radio signal strength of mobile device receive as reference signal and compare to each of beam, the highest signal received is selected than microcontroller will lock to the desire beam. A few samples of received signal strength to be analysis by an algorithm to avoid multiple signals and select actual signal strength received. In this experiment 2.45 GHz ISM band used for the transmitter and receiver and testing have been conducted in outdoor environment. Results shows that switched beam smart antenna working fine base on mobile device location and able to switch the beam while mobile device is moving