UMTS Research Articles

Compact planar active integrated inverted‐F antenna with frequency reconfigurable capability

This study presents two compact high-efficiency active integrated antennas (AIAs) working at 2.15 GHz. Both AIAs are realised by integrating the planar inverted-F antenna (PIFA) at the back side of the class-E power amplifier. In the first design, the antenna input impedance is transformed into an optimum impedance of the power amplifier. It achieves the maximum power added efficiency (PAE) of 68.6% with a total dimension of 0.36λ0 × 0.32λ0 × 0.03λ0 (λ0 is calculated at 2.15 GHz). In the second design, the antenna directly connected to the drain terminal of the power amplifier and offers a maximum PAE of 74% with a compact size of 0.21λ0 × 0.17λ0 × 0.04λ0, results in the size reduction of 59%. The novelty of the second design is it offers frequency reconfigurable nature by moving the shorting plate of PIFA without scaling the power amplifier and antenna, which can support Universal Mobile Telecommunications System (UMTS) (1920–2170 MHz), long term evolution (LTE)-40 (2300–2400), and Worldwide Interoperability for Microwave Access (WiMAX) (2500–2690 MHz) frequency bands. The measured results demonstrate that the proposed reconfigurable AIA yields the maximum PAE of 64% at both frequencies 2.3 and 2.6 GHz.

Metamaterial-based energy harvesting for GSM and satellite communication frequency bands

A metamaterial-based energy harvesting structure has been designed and experimentally tested in this study. The proposed structure has square and split ring resonators placed in different angles on the back and front sides for compatible multiband operation in energy harvesting. Resonance points have been defined at 900 MHz, 1.37 GHz, 1.61 GHz, 1.80 GHz, and 2.55 GHz, by simulation and experimental methods. These points correspond to Global System for Communication (GSM) 900, GSM 1800, Universal Mobile Telecommunication System (UMTS), satellite navigation, and Industrial Scientific and Medical (ISM) band frequencies. Supporting multiband application in a single structure without changing dimensions or design is one of the properties of this study. To harvest captived electromagnetic energy, an HSMS 2860 Schottky diode has been used. For wireless power transmission efficiency, voltage across the Schottky diode has been measured by a spectrum analyzer in different points experimentally. The maximum obtained voltage across the Schottky diode is 90 mV at 1800 MHz when a 500 mV signal is applied from a 5 cm distance. Simulated and experimental results prove that the proposed structure can effectively be used in GSM, satellite communication, and UMTS electromagnetic bands for energy harvesting and filtering applications.

Symptom Presentation in Idiopathic Environmental Intolerance With Attribution to Electromagnetic Fields: Evidence for a Nocebo Effect Based on Data Re-Analyzed From Two Previous Provocation Studies.

Individuals with idiopathic environmental illness with attribution to electromagnetic fields (IEI-EMF) claim they experience adverse symptoms when exposed to electromagnetic fields (EMFs) from mobile telecommunication devices. However, research has consistently reported no relationship between exposure to EMFs and symptoms in IEI-EMF individuals. The current study investigated whether presence of symptoms in IEI-EMF individuals were associated with a nocebo effect. Data from two previous double-blind provocation studies were re-analyzed based on participants’ judgments as to whether or not they believed a telecommunication base station was “on” or “off”. Experiment 1 examined data in which participants were exposed to EMFs from Global System for Mobile Communication, Universal Mobile Telecommunications System, and sham base station signals. In Experiment 2, participants were exposed to EMFs from Terrestrial Trunked Radio Telecommunications System and sham base station signals. Our measures of subjective well-being indicated IEI-EMF participants consistently reported significantly lower levels of well-being, when they believed the base station was “on” compared to “off”. Interestingly, control participants also reported experiencing more symptoms and greater symptom severity when they too believed the base station was “on” compared to “off”. Thus, a nocebo effect provides a reasonable explanation for the presence of symptoms in IEI-EMF and control participants.

The Effect of a Single 30-Min Long Term Evolution Mobile Phone-Like Exposure on Thermal Pain Threshold of Young Healthy Volunteers.

Although the majority of mobile phone (MP) users do not attribute adverse effects on health or well-being to MP-emitted radiofrequency (RF) electromagnetic fields (EMFs), the exponential increase in the number of RF devices necessitates continuing research aimed at the objective investigation of such concerns. Here we investigated the effects of acute exposure from Long Term Evolution (LTE) MP EMFs on thermal pain threshold in healthy young adults. We use a protocol that was validated in a previous study in a capsaicin-induced hyperalgesia model and was also successfully used to show that exposure from an RF source mimicking a Universal Mobile Telecommunications System (UMTS) MP led to mildly stronger desensitization to repeated noxious thermal stimulation relative to the sham condition. Using the same experimental design, we did not find any effects of LTE exposure on thermal pain threshold. The present results, contrary to previous evidence obtained with the UMTS modulation, are likely to originate from placebo/nocebo effects and are unrelated to the brief acute LTE EMF exposure itself. The fact that this is dissimilar to our previous results on UMTS exposure implies that RF modulations might differentially affect pain perception and points to the necessity of further research on the topic.

Performance analysis of integrated WLAN-WiMAX-UMTS networks for multimedia applications

Next Generation Wireless networks (NGWN) are the integration of different types of available wireless networks. These integrated networks will provide seamless connectivity for multimedia user applications. Among various wireless networks, the networks such as Wireless Local Area network (WLAN), Worldwide Interoperability for Microwave Access (WiMAX) and Universal Mobile Telecommunications System (UMTS) have their own unique characteristics and support for wide range of multimedia user applications. So, the integration of these networks and their performance analysis in respect of Quality of Service (QoS) is a major concern nowadays. Hence, this paper deals with the integration of WLAN, WiMAX and UMTS networks by considering QoS parameter. Further, the integration of these networks are analyzed with loose coupling and tight coupling architecture along with and without QoS. Furthermore, the performance analysis of the above mentioned integrated network for multimedia applications is also done. The simulation is performed through Opnet simulator.

Study of the correlation between outdoor and indoor electromagnetic exposure near cellular base stations in Leuven, Belgium

A measuring campaign for the assessment of electromagnetic radiation near base stations in the city center of Leuven, Belgium, has been carried out. The main objective of this assessment is to study the correlation between the outdoor and the indoor exposure produced by cellular base stations and to investigate the changes of electromagnetic exposure within a typical day and over 1 month in the vicinity of these base stations. The study was also carried out as a function of location and time using highly precise measurement equipment. The measurements were performed in both public and private areas in sixty (30 indoor and 30 outdoor) different locations in Leuven. The measurement was focused on mobile communication networks: GSM (Global System for Mobile Communication, 900 MHz and 1800 MHz) and UMTS (Universal Mobile Telecommunications System, 2110 MHz) were the frequency bands of interest. The data at these frequencies were extracted from raw measurements in the 824–2170 MHz frequency band. The results show that all analyzed locations are in compliance with the exposure limits recommended by ICNIRP (International Commission on Non-Ionizing Radiation Protection) and that the (maximum) indoor exposure correlates to the outdoor exposure with a factor of about 0.5.

Next Generation New Radio Small Cell Enhancement: Architectural Options, Functionality and Performance Aspects

The 3rd generation partnership project (3GPP) has been engaged in further advancing the evolved universal mobile telecommunications system (UMTS) terrestrial radio access network (E-UTRAN) and UTRAN based radio access network technologies. New radio (NR) is the 3rd generation partnership project (3GPP) endeavor for outlining and standardization of the 5th generation (5G) advanced radio access technology. 3GPP has released the first set of 5G NR standards, i.e., the non-standalone 5G radio specifications. As long-term evolution (LTE) technology is massively deployed and broadly accepted, the transition from LTE to 5G is very critical, and it is of maximal importance that the backward compatibility of 5G with LTE is considered. 3GPP has identified several architecture options for 5G. This article gives an overview of the NR architecture options, their deployment scenarios, and the key migration paths. The LTE-NR dual connectivity (DC) is presented. This DC scenario is unique in the sense that DC is being endowed for two different generations of 3GPP radio access technologies. We, further, present the integration of multipath transmission control protocol (MPTCP) with LTE-NR DC and DC-like aggregation, i.e., 3GPP-non-3GPP interworking to bring in the advantages of MPTCP in terms of link robustness, reliability and dynamic mapping between the traffic flows and the available paths. Finally, we discuss the future research and standardization directions of the next-generation networks.

Analytical Study of a Dual Pointer Based Strategy for Location Update Using Node B Sojourn Time in UMTS Networks

This article describes how Universal Mobile Telecommunications System (UMTS) is a 3G cellular network standard that uses location update (LU) and location search (LS) for mobility management. LU requires update in two location registers (LRs) - home LR (HLR) and visiting LR (VLR) - where one HLR controls multiple VLRs. HLR updates (HLRUs) are costlier, and hence should be less frequent. To achieve it, VLRs maintain a forward pointer chain among themselves, instead of updating HLR. But a lengthy chain increases LS cost considerably. So, we propose to restrict the chain length to unity by introducing an additional backward pointer, and using the concept of root-VLR similar to the home agent concept of mobile IP. We derive a closed form solution to approximate the average HLRUs per call, and substantiate it by simulation in cases of both random and diurnal mobilities. Results reveal substantial reduction in HLRUs per call, even when call-to-mobility ratio is high. UMTS operators will find the analysis worth considering, while managing their 3G networks.

Frequency and polarization reconfigurable microstrip antenna

This paper presents a dual band frequency and polarization reconfigurable microstrip antenna. The simple design consists of two slots and two feeds. In one slot there is a switch. The two feeds are positioned on the right and left diagonal of microstrip antenna. When the switch is ON the electrical size of antenna becomes small and it resonates at higher UMTS 2100 MHz band with circular polarization. Similarly, when the switch is OFF then size of antenna is large and it operates at lower UMTS 1900 MHz band with elliptical polarization. The sense of polarization can be easily changed from right handed to left handed by changing the feed position. The radiation pattern is not disturbed by switch state and gain of proposed antenna is above 5 dBi. This antenna can be used in emerging reconfigurable wireless communication systems.

Design and study of multiband planar wheel‐like fractal antenna for vehicular communication applications

AbstractIn this article a multiband antenna is proposed for potential vehicular communication applications that falls under sub‐6 GHz band such as IMT2000, GSM1800/1900, LTE, universal mobile telecommunication system, WLAN, dedicated short‐range communication, and so on. A conventional circular monopole radiating element is used in this design with partial ground plane and later it is modified by incorporating the circular slots in a tree‐like fractal structure. The novel defected ground structure consisting of a semi‐circular slot and a pair of mirror‐imaged quarter circles introduced at the top edge of the partial ground, which lies exactly beneath the microstrip line feed. The structural parameters are optimized to obtain the desired pass band performance under vehicular bands. Further, to investigate the antenna performance in the vehicular environment, it is virtually placed on the top of a car model and the radiation performance is analyzed and are presented in this work. The antenna is prototyped, and the measurement results are providing good correlation with that of simulation results.

Security Requirement and Standards for 4G and 5G Wireless Systems

In this article, we give an overview on the security requirements and standards for the fourth generation (4G) long term evolution (LTE) and the fifth generation (5G) wireless systems. Compared with the third generation (3G) universal mobile telecommunication system (UMTS), the LTE system not only improves the network capacity and coverage but also provides better performance of data rate, access latency, energy efficiency (EE), and spectrum efficiency (SE) [1]. With the increasing data usage and the new multimedia applications, LTE technologies have been proposed by the 3rd generation partnership project (3GPP) as the broadband mobile wireless networks with packet switched, IP-based technology solely, fully inter-working with different access technologies, different types of base stations and relay nodes. To support more use cases with unique service requirements, 5G wireless systems are developed. There are eight advanced features for 5G wireless systems, 1-10 Gbps connections to end points in the field, 1 millisecond latency, 1000x bandwidth per unit area, 10-100x number of connected devices, 99.999% availability, 100% coverage, 90% reduction of network energy usage and up to ten years battery life for low power devices [2]. These advanced features make 5G wireless systems capable of supporting many new use cases, new industry applications, a multitude of devices and applications to connect society at large. Due to the introduction of new characteristics, there are many new security requirements in the design of the security architectures of the 4G LTE and 5G wireless systems.

Over-the-Air Tests of High-Speed Moving LTE Users in a Reverberation Chamber

High-speed trains are nowadays a reality in most of the countries. Internet services and connectivity are required by the passengers on board using smartphones and laptops. Nevertheless, the higher the speed, the bigger the issues that operators have to face to implement mobility and to reduce the effect of fast fading signal and Doppler shift, which may cause throughput reduction and problems to access the network. In the past, operators tried to optimize the cellular access to universal mobile telecommunications system cells covering railways. Now that 4G networks have become mature and deployed, a similar approach needs to be optimized and implemented to long-term evolution cells covering the same targets. We present the results of a testing campaign replicating real “high-speed train” propagation scenarios, like a train running in open space or in tunnels with the help of a reverberation chamber. The chamber was partially filled by absorbing panels and equipped with rotating stirrers in order to approach the multipath propagation and to replicate the fading conditions that is typical of smartphones in a train coach. The effects of Doppler and its fast variations are presented, together with an analysis of the efficiency of different transmission solutions for tunnels (single-input single-output cells propagating inside them). The testing sessions were performed under a collaboration program between Telecom Italia (in the paper referred as “operator”), Nokia Networks, and Universita Politecnica delle Marche. After the experiments in our laboratory, some features were introduced in the operator's live network, covering the high-speed railway between the two Italian cities of Piacenza and Bologna.

Transparent and conformal wheel-shaped fractal antenna for vehicular communication applications

In this article, a low cost, compact conformal antenna is proposed for vehicular communications applications. The concept of fractal geometry is applied in this design to make the model more attractive in its appearance as well as to attain desired bands in the vehicular communication spectrum. It is fabricated on a transparent and flexible poly vinyl chloride material of size 55 mm × 40 mm × 3 mm. The proposed antenna is intended to operate in GSM-1800/1900, Digital Communication System (DCS-1800), Personal Communication Service (PCS-1900), Universal Mobile Telecommunications System (UMTS), Long-Term Evolution (LTE2600), Industrial, Scientific, and Medical radio band (ISM 2.4G), Wireless local area network (WLAN), Bluetooth, World Interoperability for Microwave Access (WiMAX), IEEE802.11p protocol based Vehicle-to-everything, Dedicated short-range communications (DSRC) and Wireless Access in Vehicular Environments (WAVE) communications bands. The prototype of the antenna in its planar and conformal versions exhibit the wideband characteristics and their measured results show good agreement with that of obtained simulation results. The virtual analysis of platform mounted characteristics of the proposed antenna at two different locations of the vehicle (vehicle roof-top and on side-view mirror) are performed in ANSYS Savant simulation tool and the corresponding far-field radiation performance is characterized.

Robust and trust dynamic mobile gateway selection in heterogeneous VANET-UMTS network

Vehicular ad-hoc network (VANET) technology is serving variable applications as it uses moving vehicles as nodes in a network to create communication independent of a central infrastructure. Various types of VANET problems have emerged because of the absence of a central infrastructure as well as the random movement of the vehicles. VANETs cannot cope with network segmentation because of frequently disconnected networks in sparse environments. Therefore, several solutions have been proposed in the literature, such as integrating the VANET with other infrastructure networks by static gateways that have been fixed along the road. However, protocols based on static gateways can provide connectivity only in areas where they are deployed. Thus, the distribution and requirement of static gateways are the main drawbacks of these protocols. In this paper, a new routing protocol for robust and trust mobile gateway selection (RTMGwS) has been proposed. RTMGwS protocol uses the characteristics of vehicle movements and variant routing parameters to select an optimal mobile gateway with high robust and trust connection to an infrastructure network. The protocol is designed to spread the advertisement messages by the mobile vehicle gateway over the integrated network architecture of VANET and universal mobile telecommunications system (VANET-UMTS) without flooding the network and seamless handovers. The proposed protocol has been validated using SUMO and NS2 simulators over highways environment. The simulation results show encouraging performance in terms of increasing the packet delivery ratio and overall throughput, reducing control packet overhead and minimizing connection delay.

A Comparative Study of PMI/RI Selection Schemes for LTE/LTEA Systems

This paper presents a joint calculation of the precoding matrix indicator (PMI) and rank indicator (RI) in multiple-input multiple-output (MIMO) downlink third generation partnership project (3GPP) universal mobile telecommunications system (UMTS)/long-term evolution (LTE) systems. The standard codebook based precoding is used where the mobile station estimates and sends some measures related to the channel state information to the base station for link adaptation purpose. We study the system performance using link-level simulation under realistic assumptions. Specifically, we use K-best MIMO decoding in the presence of perfect and imperfect estimation of the channel and the noise variance, as well as white and colored noise plus interference defined by the 3GPP LTE specification documents. Similar to some previous results, our method for calculating the PMI/RI is based on maximizing the mutual information between the transmitted and received symbols with respect to the precoding matrix. We evaluate the system performance using two channel measures when computing the mutual information. The first measure is the estimated channel whereas the second one is the estimated channel covariance matrix. Although these two measures have been used in different literature, there have not been conclusive results on which one should be used in different practical scenarios. We assess the system performance using Monte Carlo simulations and compare different test cases, e.g., 3GPP channel models, wideband, and subband PMI/RI calculation, white/color noise plus interference, etc. We then conclude our work with technical recommendations for different scenarios.

Impact of the Mobility Management Protocols on the Handover Performance Assessment Under Real-Time Video Steaming Network

In recent years, wireless networks have evolved tremendously especially in heterogeneous systems in order to effectively and efficiently support multiple access technologies. Heterogeneous networks will be paramount in the next generation wireless networks where devices are able to roam under various radio access technologies that lead to utilization of an IP-based core network. With the increasing accessibility and performance of different radio access technologies which are WiMAX (Worldwide Interoperability for Microwave Access), Wi-Fi (Wireless Fidelity) and UMTS (Universal Mobile Telecommunications System) have stimulated the mobile users towards increased of utilization. In such network, it is imperative for handovers between networks in order to maintain the seamless connectivity and a satisfactory quality of service for mobile users. Therefore, providing the quality of service (QoS) and seamless handover processes is one of the major matters for real-time services. This paper proposes a unified handover scheme to reduce the latency period of vertical handover during the video transmission. The proposed scheme is evaluated based simulation work on the handover performance under real-time video streaming networks.

Window RF Shielding Film Using Printed FSS

Frequency-selective surfaces (FSSs) on thin substrates using screen printing technology are popular due to their flexible nature, low profile, easy installation, and low-cost mass production. This paper proposes the deployment of screen printed FSS on window panes in office buildings and investigates the shielding effect on the radio wave propagation through such structures. The shielding surface is an array of modified meandered squares with a unit cell size $0.083\lambda _{o}$ , on a flexible transparent substrate (polyethylene terephthalate) of relative permittivity 3.4. This sheet was then bonded on the window glass. With this FSS, desirable shielding is achieved in the frequency range from 1.5 to 2.5 GHz, with a potential application of shielding for the Universal Mobile Telecommunications System 2 GHz frequency band, while allowing all other bands to pass with little attenuation. Investigations involved the transmission response through the unprinted and printed substrate with and without standard window size float glass. With the optimized FSS design, good agreement was achieved between the theoretical and experimental results, validating the manufactured prototype. Measurements indicate that the FSS window has approximately 38 dB better rejection in 1.5–2.5 GHz band than that of the unshielded window. However, the notch frequency depends on the permittivity and thickness of the glass, and the angle of incidence on the surface. The FSS design can be tuned to shield various frequency bands by rescaling the various physical parameters of the element.

Distance tracking scheme for seamless handover in IMS-based systems with UMTS access network

This paper proposes a fast and seamless handover scheme for systems based on IP Multimedia Subsystem (IMS) architectural framework with Universal Mobile Telecommunications System (UMTS) access network. In the scheme the location, direction and movement pattern of a Mobile Node (MN) in a network cell are proactively tracked in order to determine the exact moment to trigger the pre-handover process with one of the adjacent cells considering MN’s direction before the execution of Layer 2 handover. The performance of the proposed scheme was evaluated by comparing it with the traditional handover scheme and the evaluation shows that the traditional handover scheme introduced a handover delay of about 675.5 ms, whereas the proposed scheme introduced handover delay of about 96.25 ms, which is less than 100 ms, hence the handover delay introduced by the proposed scheme fall within the specified range of best class service for voice traffic and streaming media over IP networks.Keywords: IMS, Handover delay, Distance Tracking, pre-handover, UMTS

Link Budget Maximization for a Mobile-Band Subsurface Wireless Sensor in Challenging Water Utility Environments

A subsurface chamber transceiver system and associated propagation channel link budget considerations for an underground wireless sensor system (UWSS) are presented: the application was a sewerage system for a water utility company. The UWSS operates over the GSM850/900, GSM1800/1900, and Universal Mobile Telecommunications System (UMTS) bands in order to operate with the standard public mobile phone system. A novel antenna was developed to minimize path loss from the underground location: a folded loop type, which is small enough to fit conveniently inside a utility manhole access chamber while giving adequate signal strength to link to mobile base stations from such a challenging environment. The electromagnetic performance was simulated and measured in both free space and in a real manhole chamber. An experimental test bed was created to determine the return loss and received signal strength with different transceiver positions below the manhole chamber access cover. Both numerical and experimental results suggested an optimum position of the unit inside the manhole, combining easy access for maintenance with viable received signal strength. This confirmed that the characteristics were adequate for incorporation in a transceiver designed to communicate with mobile base stations from underground. A field trial confirmed the successful operation of the system under severe conditions.

Analysis and Synthesis of Double Negative Dielectric Media Rectenna Systems for Ambient Microwave Energy Harvesting

The concept of harvesting the ambient electromagnetic radiation energy, coming from public telecommunication wireless networks, has been recently subject of extensive research. Techniques proposed for this target use mainly antennas, as the grade gathering the radiation power. In this work, a method introducing the usage of specific dielectric structures with artificially negative electric permittivity and magnetic permeability (double negative media or DNG) in combination with wire dipole antenna sensors is proposed as an RF harvesting system. Theoretical study of the synthesized DNG medium’s performance and the distribution of the electromagnetic field in its interior is made, with the intention of finding the areas of maximum electric field intensity at which the antenna sensors would be positioned for maximum power scavenging. The received numerical results show that the synthesized schemes are capable of enhancing the energy gathering ability. Compared to the same antenna sensors positioned in free space, they ensure higher input voltage to the rectifier and also an increase of the available power about 10 dB. Moreover, they exhibit this performance for every direction of arrival of the incoming waves. The hybrid schemes DNG dipole antenna were designed for the Universal Mobile Telecommunication System (UMTS) frequency band, but the method is general and would be applied to any other frequency band and also with other antenna types.