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In August 2023, Xiaomi unveiled the Redmi K60 Ultra, the first multi-frequency smartphone integrated with BeiDou-3 Navigation Satellite System Precise Point Positioning (PPP-B2b) services and employing PPP technology as the primary positioning method. The positioning enhancement service is provided by the Assisted Global Navigation Satellite System (A-GNSS) location platform developed by the China Academy of Information and Communications Technology. The signaling interaction between the server and the users strictly adheres to the Third Generation of Mobile Communications Technology Partnership Project Long-Term Evolution Positioning Protocol and the Open Mobile Alliance Secure User Plane Location framework. To comprehensively evaluate the Redmi K60 Ultra's capabilities, this study designed six distinct experimental scenarios and conducted comprehensive research on multi-frequency and multi-GNSS observation noise, Time to First Fix (TTFF), as well as the performance of both GNSS-based and network-based positioning. Experimental results indicate that the GNSS chipset within the Redmi K60 Ultra has achieved a leading position in the consumer market concerning supported satellite constellations, frequencies, and observation accuracy, and is comparable to some low-cost GNSS receivers. A-GNSS positioning can reduce the TTFF from 30 to under 5 s, representing an improvement of over 85% in the cold start speed compared to a standalone GNSS mode. The positioning results show that the A-GNSS PPP-B2b service can achieve positioning performance with RMS errors of less than 1.5 m, 2.5 m, and 4 m in open-sky, realistic, and challenging urban environments. Compared to GNSS-based positioning, cellular network-based Observed Time Difference of Arrival (OTDOA) positioning achieves an accuracy ranging from tens to hundreds of meters in various experimental scenarios and currently functions primarily as coarse location determination. Additionally, this study explores the potential of the Three-Dimensional Mapping-Aided (3DMA) GNSS algorithm in detecting Non-Line-of-Sight signals and enhancing positioning performance. The results indicate that 3DMA PPP, as compared to conventional PPP, can significantly accelerate PPP convergence and improve positioning accuracy by over 30%. Consequently, 3D city models can be utilized as future assistance data for the A-GNSS location platform. [ABSTRACT FROM AUTHOR]

The network organization of the systems of economic entities, which are distributed remotely over large territories, require the creation of high-quality communications for them. The purpose of present work was to demonstrate the possibility of using the latest means of communication based on Long-Term Evolution and Multiple-Input Multiple-Output technologies (LTE- and MIMO-technologies) in 3G and 4G networks to solve contemporary tasks of organizing of high-quality mobile communication in some places of the territory of Ukraine for the works that need biological and medical information in rarely settled, remote regions. The publication provides the author's data on the practical organization of communication in rural areas and considers the following issues. 1- Determination of spatial parameters of the LTE standard network. 2- Preparation of a map of the area. 3- Choosing an LTE network planning option. 4- Principles of construction and operation of LTE networks. 5- P-GW (Packet Data Network Gateway) functions. 6- MME (Mobility Management Entity) functions. 7- Functions of PCRF. MME (Mobility Management Entity) functions. 8- Functions of PCRF. 9- Peculiarities of using upper and lower frequencies for LTE. 10- Application of MIMO technology in LTE. 11- Application of MIMO technology in 3G and 4G networks. The results of the performed works can be applied for the networked structures development for the use in domestic economy, agriculture, for the science branches like biology, nature protection, and for information systems for such branches. In the result of the work done the type of antenna, other equipment were suggested; they should be used to strengthen 3G and 4G Long-Term Evolution communication in such conditions, as well as suitable 4G antenna for modem or router. Obtained results are suitable for providing of the work of information systems in agriculture, ecological monitoring, other areas of activities, based on biological and medical information; they all need quick data exchange as well as for scientific centers, other settlements, for which such communication possibilities primarily were developed. [ABSTRACT FROM AUTHOR]

While some unmanned aerial vehicles (UAVs) can operate with a given degree of autonomy (e.g., path following, obstacle avoidance, auto return, and other flight modes), many civilian drones have a safety pilot standby all the time for abnormal conditions. This is typically done within line-of-sight (LOS) due to regulations. While flying within LOS, radio frequency communication remains a popular alternative for retail pilots. For beyond line of sight operations, given the availability of cellular technologies, the UAV community has explored the possibility of using the cellular network instead, which could bring benefits such as an additional channel for control and telemetry, extension of range, and allowing the UAV to interact with cloud services while it flies, via a data connection. With the current prevalence of data supporting communication over 3G and 4G networks, the following representative technologies have been used for long-distance control—short message service (SMS), transmission control protocol (TCP), message queue telemetry transport (MQTT), and the so-called "protocol-independent" service PubNub. While the safety of drone flights is highly prioritized by regulators, the issue becomes even more highlighted when control commands are transmitted via cellular network channels (e.g., 4G long-term evolution, SMS) which can introduce time delays in communication chains and degrade pilot's ability to properly control UAVs. This article reviews common UAV communication protocols over cellular links and presents a technique for measuring and modeling delays over such channels. The quality-of-fit for the proposed models is measured for different communication protocols, short versus long-range communication, and different UAV operation modes. Finally, details are presented for a system that manipulates a drone via the cellular network and latency is measured for such system. [ABSTRACT FROM AUTHOR]

Phone number is a unique identity code of a mobile subscriber, which plays a more important role in the mobile social network life than another identification number IMSI. Unlike the IMSI, a mobile device never transmits its own phone number to the network side in the radio. However, the mobile network may send a user's phone number to another mobile terminal when this user initiating a call or SMS service. Based on the above facts, with the help of an IMSI catcher and 2G man-in-the-middle attack, this paper implemented a practicable and effective phone number catcher prototype targeting at LTE mobile phones. We caught the LTE user's phone number within a few seconds after the device camped on our rogue station. This paper intends to verify that mobile privacy is also quite vulnerable even in LTE networks as long as the legacy GSM still exists. Moreover, we demonstrated that anyone with basic programming skills and the knowledge of GSM/LTE specifications can easily build a phone number catcher using SDR tools and commercial off-the-shelf devices. Hence, we hope the operators worldwide can completely disable the GSM mobile networks in the areas covered by 3G and 4G networks as soon as possible to reduce the possibility of attacks on higher-generation cellular networks. Several potential countermeasures are also discussed to temporarily or permanently defend the attack. [ABSTRACT FROM AUTHOR]

Well-deployed cellular networks offer a cheap wireless solution for the control channel deployment of Remote-Control Vehicles (RCV) and Unmanned Aerial Vehicles (UAV). However, a cellular data transfer service performance is affected by a different kind of User Equipment (UE) mobility. Operating conditions of UAV imply working at different altitudes, variable velocities with accelerations/decelerations and rapidly changed antennas angular position, which lead the wireless signal to be prone to negative effects. Available field measurement studies are not sufficient to provide excessive information on degradation problem causes for UEs moving along a complex trajectory. This paper presents an evaluation of the service quality of live operational 3G and LTE networks for both ground moving and flying UE. It has been found that antennas angular position variations in 3D (for example, during UAV manoeuvers) increase data transfer latency and jitter. Moreover, this effect in conjunction with higher interference at high altitudes may partially or fully block the data transfer service. This paper has been prepared to draw attention to the problem that makes the cellular data transfer service unusable for highly-manoeuvrable UAVs. [ABSTRACT FROM AUTHOR]

A novel magneto-electric dipole antenna with wide H-plane beamwidth, triple-linear polarisation and frequency reconfiguration is proposed for 5G communications. In this study, the radiated dipoles are designed with the arc-shaped planes to exhibit wide H-plane performance. A bent cross-dipole feed with PIN diodes and varactor diodes inserted into its four arms at different altitudes is utilised to excite and control the antenna. Consequently, a measured wide beamwidth ranging from -67° to 67° can be achieved in H-plane. In addition, the height of the proposed antenna decreased about 30% due to the bent designs. Finally, by controlling the PIN diodes and varactor diodes, the three kinds of linear polarisations and frequency reconfiguration functionalities for 2G/3G/LTE/5G applications can also be easily obtained. With the above-mentioned features, the proposed antenna well suits for intelligent base-station communications. [ABSTRACT FROM AUTHOR]

This paper proposes a dual-band dual-polarized planar antenna array with flat-top and sharp cutoff radiation patterns for 2G/3G/LTE base stations. The array consists of $8 \times 8$ antenna elements arranged with nonuniform spacings and is assigned with optimized nonuniform excitations to achieve flat-top and sharp cutoff radiation patterns with low sidelobes. The radiating element consists of two square-shaped PCB boards. Extra adjustable coupling elements are introduced in the H-shaped patches to improve the impedance matching performance in an array environment as well as to reduce the size of the antenna element. In the 1.71–2.69 GHz band, the dual-polarized radiating element exhibits stable radiation patterns, excellent impedance matching (VSWR < 1.5), and high isolations (>40 dB). Frequency band selective variables are defined to group the antenna elements. They are optimized along with the element spacings and complex excitations in the optimizer to ensure stable flat-top radiation patterns. Rectangular-shaped baffles are introduced to reduce mutual couplings. A prototype of the $8 \times 8$ antenna array has been fabricated and measured. The results indicate that the proposed dual-band dual-polarized planar array achieves a half-power beamwidth of 50° ± 5° in both the H-plane and E-plane. The proposed antenna and its array exhibit attractive potentials for 2G/3G/LTE base station applications. [ABSTRACT FROM AUTHOR]

This paper considers the hidden-node problem in downlink transmission of an LTE-U and WiFi coexistence system operating in unlicensed bands. An enhanced LTE-U node structure is first presented, in which a WiFi module is introduced in an LTE-U eNB, and the RRC and MAC functional blocks in both LTE-U eNB and LTE-U UE are redefined. The purpose is to enable information exchange between an LTE-U node and a WiFi node in order to handle the hidden-node problem. Based on the enhanced LTE-U node structure, an enhanced listen-before-talk (e-LBT) mechanism is further presented, which incorporates an RTS/CTS handshaking procedure in the basic LBT mechanism. To support RTS/CTS handshaking, the relevant information that needs to be exchanged between e-MACWiFi in the WiFi module and e-RRC in the LTE-U module of an LTE-U node is identified, and the message format to be exchanged between e-MACWiFi and e-RRC is defined. Simulation results show that the proposed e-LBT mechanism can significantly improve the performance of the coexistence system in terms of the LTE-U system throughput and WiFi system throughput as compared with the basic LBT mechanism. [ABSTRACT FROM AUTHOR]

Deploying femtocells has been taken as an effective solution for removing coverage holes and improving wireless service performance in 3G-beyond wireless networks such as WiMAX and Long Term Evolution (LTE). This article investigates a novel framework of dynamic spectrum management for femtocell networks, called cognitive-empowered femtocells (CEF), aiming at mitigating both cross-tier and intratier interferences with minimum modifications required on the corresponding macrocell network. With the proposed framework, each CEF base station (BS) and the femtocell users can utilize spatiotemporally available radio resources for the access traffic. We conclude that the proposed CEF framework can effectively complement the existing femtocell design and serve as a value-added feature to the state-of-the-art femtocell technologies, while achieving high scalability and interoperability by minimizing the required modifications on the macrocell protocol design. [ABSTRACT FROM AUTHOR]

To meet the explosive growth of mobile data traffic, ultra-dense networks have emerged to enhance spatial and spectral efficiency. Densely deployed small cell architecture faces several major challenges, including low infrastructure utilization ratio, severe inter-cell interference, and so on. In this article, we aim to develop a novel super base station (SupBS) network architecture to tackle these issues. The proposed SupBS architecture consists of two layers, namely, an infrastructure layer and a virtualized network layer. In the infrastructure layer, there are three key physical components: the hybrid heterogeneous radio unit pool, line interface switch unit, and computing resources pool. In the virtualized network layer, there are two logical modules designed on top of the three physical components, namely, the virtualized base station and virtualized software defined core network. The two logical modules are designed to facilitate the use of the underlying three physical components by reducing the energy consumption and processing delay. We present the functionalities of the two virtualized modules and explain how they are utilized to create virtual networks. Moreover, we demonstrate a recently developed SupBS prototype, and provide an application scenario for this prototype in an Internet information broadcast-storage system to show the advantages of our architecture. [ABSTRACT FROM AUTHOR]

The article introduces a method of performing a radio link quality assessment based on the Link Quality Indicator (LQI) which will be calculated for every system that is available. The method presented has been developed during the netBaltic project completed in Poland and generally applies to the so-called maritime zone A, i.e. the sea area where ships are still within the range of shore-based radio communication systems, particularly 3G/LTE cellular networks. The algorithm was developed based on the results of measurements obtained during two separate campaigns. That measurement data served as a basis for the method's initial assumptions and was utilized during the method's verification. [ABSTRACT FROM AUTHOR]

The growing complexity of heterogeneous cellular networks (HetNets) has necessitated a variety of user and base station (BS) configurations to be considered for realistic performance evaluation and system design. This is directly reflected in the HetNet simulation models proposed by standardization bodies, such as the 3rd Generation Partnership Project (3GPP). Complementary to these simulation models, stochastic geometry-based approach, modeling the locations of the users, and the $K$ tiers of BSs as independent and homogeneous Poisson point processes (PPPs), has gained prominence in the past few years. Despite its success in revealing useful insights, this PPP-based K$ -tier HetNet model is not rich enough to capture spatial coupling between user and BS locations that exists in real-world HetNet deployments and is included in 3GPP simulation models. In this paper, we demonstrate that modeling a fraction of users and arbitrary number of BS tiers alternatively with a Poisson cluster process (PCP) captures the aforementioned coupling, thus bridging the gap between the 3GPP simulation models and the PPP-based analytic model for HetNets. We further show that the downlink coverage probability of a typical user under maximum signal-to-interference-ratio ( \mathtt {SIR} ) association can be expressed in terms of the sum-product functionals over PPP, PCP, and its associated offspring point process, which are all characterized as a part of our analysis. We also show that the proposed model converges to the PPP-based HetNet model as the cluster size of the PCPs tends to infinity. Finally, we specialize our analysis based on general PCPs for Thomas and Matérn cluster processes. Special instances of the proposed model closely resemble the different configurations for BS and user locations considered in 3GPP simulations. [ABSTRACT FROM PUBLISHER]

Machine Type Communication (MTC), as one of the most important wireless communication technologies in the future wireless communication, has become the new business growth point of mobile communication network. It is a key point to achieve seamless handovers within Evolved-Universal Terrestrial Radio Access Network (E-UTRAN) for massive MTC (mMTC) devices in order to support mobility in the Long Term Evolution-Advanced (LTE-A) networks. When mMTC devices simultaneously roam from a base station to a new base station, the current handover mechanisms suggested by the Third-Generation Partnership Project (3GPP) require several handover signaling interactions, which could cause the signaling load over the access network and the core network. Besides, several distinct handover procedures are proposed for different mobility scenarios, which will increase the system complexity. In this paper, we propose a simple and secure uniform group-based handover authentication scheme for mMTC devices based on the multisignature and aggregate message authentication code (AMAC) techniques, which is to fit in with all of the mobility scenarios in the LTE-A networks. Compared with the current 3GPP standards, our scheme can achieve a simple authentication process with robust security protection including privacy preservation and thus avoid signaling congestion. The correctness of the proposed group handover authentication protocol is formally proved in the Canetti-Krawczyk (CK) model and verified based on the AVISPA and SPAN. [ABSTRACT FROM AUTHOR]

In 3GPP LTE Release 13, Narrowband Internet of Things (NB-IoT) was standardized for providing wide-area connectivity for massive machine-type communications for IoT. In LTE Release 14, NB-IoT was further developed to deliver enhanced user experience in selected areas through the addition of features such as increased positioning accuracy, increased peak data rates, the introduction of a lower device power class, improved non-anchor carrier operation, multicast, and authorization of coverage enhancements. In this article, we provide an overview of these features introduced for NB-IoT in LTE Release 14. An analysis is given on the applicability of these features and their benefits to enhance the NB-IoT radio access technology. [ABSTRACT FROM AUTHOR]

The traditional cellular network cannot keep pace with the dramatic growth in data traffic due to exponentially increasing number of multimedia applications and mobile subscribers. Recently, femto base stations (FBSs) are deployed with the macro base station (MBS) tier for off-loading the data traffic and to improve the indoor coverage of the heterogeneous cellular network. However, FBS deployment also increases the cross-tier interference of the heterogeneous cellular network resulting in outage performance degradation of MBS tier. This work develops an analytical framework to limit the cross-tier interference of MBS tier using power control scheme (PCS). The proposed PCS works on path loss inversion and location-based power level rule for FBS. Moreover, a cooperation scheme and an association policy with MBS (CSAPM) are introduced to improve the outage performance of the FBS tier. Tools from the stochastic geometry are used for deriving the signal to interference and noise ratio outage probability, total outage probability, and area spectral efficiency (ASE) of MBS tier and FBS tier. Additionally, ASE maximization problem is formulated to evaluate the optimal density of FBSs. The effectiveness of the proposed PCS and CSAPM on outage performance and ASE are numerically demonstrated. It is noted from the results that the proposed CSAPM can compensate the loss in outage performance of FBS tier due to PCS. Finally, simulation results validate the analytical results. [ABSTRACT FROM AUTHOR]

The extension of long term evolution (LTE) networks in unlicensed spectrum areas under the licensed assisted access concept aims at achieving higher transmission rates via the aggregation of the aforementioned bands along with the licensed ones within the 3G Partnership Project framework. A prospect carrier aggregation (CA) scheme should handle efficiently the coexistence of the LTE systems that compete for the same unlicensed spectrum areas along with their incumbent users (i.e., Wi-Fi). In this paper, a novel CA scheme is proposed for licensed/unlicensed MIMO LTE systems that allocates optimally the resources (power and resource blocks) of an evolved Node B to user equipments. Furthermore, the proposed approach handles the coexistence matters within the unlicensed bands with an efficient decentralized way. The new scheme involves the solution to a mixed integer nonlinear programming problem and thus, an optimal low complexity method is proposed based on the Lagrange dual decomposition. Furthermore, the proposed technique is extended to the imperfect channel state information (CSI) case. To that end, a novel listen-before-talk scheme is developed via which the required unlicensed bands CSI are estimated in a blind manner. The performance of all of the proposed techniques is verified via indicative simulations. [ABSTRACT FROM AUTHOR]

The next generation of cellular networks is expected to provide huge capacity, and site densification is one of the possible solution to increase the network capacity. The target of this paper is to show the impact of macro/micro site densification and higher order sectorization on signal strength, signal quality and throughput in LTE network. It also highlights the impact of site and sector densification on the cell overlapping and cell border areas. A detailed techno-economical analysis along with area power consumption and area spectral efficiency is also provided in this paper. In site densification, the intersite distance (ISD) between the base station sites is decreased, which results in strong inter cell interference. The results presented in this paper show that the spectral efficiency of the cell decreases with the site densification. However, the average area spectral efficiency increases due to a larger number of cells in the densified network. At the same time the number of cell border users overlapped by multiple servers also increases with the site and sector densification. It is shown that in one square kilometer, increasing the number of cells from 14 (3-sector site with 500 m ISD) to 693 (6-sector site with 100 m ISD) relatively improves the area spectral efficiency by 24.5 times at the cost of 49.5 times more number of cells. Almost identical power efficiency is provided with 3-, and 6-sector site. However, a higher order sectored site was found to be more cost efficient. [ABSTRACT FROM AUTHOR]

The third generation partnership project (3GPP) long-term evolution (LTE) cellular system offers high data rate capabilities by leveraging several techniques including link adaptation and frequency selective scheduling. These techniques rely on accurate channel quality indicator (CQI) feedback reports that are sent by the user equipment (UE) to the evolved node B, a process which results in high signalling overhead. In this study, the authors propose a UE-assisted sub-band feedback compression scheme based on a predictive filtering technique to reduce this signalling overhead. Four schemes based on adaptive filters have been designed, implemented and tested in an LTE system level simulator. Simulation results indicate that the proposed compression scheme has shown efficacy with an overall CQI feedback signalling reduction of up to 92.5% whilst maintaining stable sector throughput, when compared with the standard 3GPP CQI feedback mechanism. Although the proposed scheme exhibits low computational and memory complexity, a reduced-complexity scheme achieving an average computational load reduction of up to 35% is also presented. [ABSTRACT FROM AUTHOR]

The latest evolution of cellular network, i.e., the heterogeneous network (HetNet) is a promising technique for facing the explosive data demands that the macro-only network can barely meet. However, unplanned small cell deployments, along with an aggressive frequency reuse scheme, generate severe interference between adjacent cells, degrading system performance. In the conventional homogeneous network, fractional power control (FPC), which consists of open-loop power control (OL-PC) and closed-loop power control (CL-PC), is used to determine adequate transmit power of user equipment (UE) to avoid inter-cell interference. However, setting the UE transmit power requires delicate awareness of uplink interference to properly avoid the severe and complicated inter-cell interference in an uplink HetNet environment. In this paper, we propose an interference-aware uplink power control scheme that considers outgoing and incoming interference in each cell in order to fully take the interference situation of the HetNet into account while setting the OL-PC parameter. By using the proposed scheme, uplink interference existing in a HetNet environment can evidently be reduced; therefore, the total cell capacity of both the macro- and the femtocell is increased by 25.6 %. Furthermore, the simulation results of a CL-PC on a 10 ms basis show that the received signal to interference-plus-noise ratio (SINR) of OL-PC with CL-PC is spread less around the target SINR compared to the case of OL-PC alone. Therefore, it is verified that the CL-PC supports the received SINR of OL-PC to meet the target SINR by compensating the channel variation caused by the fading effect. [ABSTRACT FROM AUTHOR]

A novel broadband dual-polarized magneto-electric (ME) dipole antenna is proposed for 2G/3G/LTE/WiMAX applications. The proposed antenna has stair-shaped feeding strips to impart a wide impedance bandwidth to it and a rectangular box-shaped reflector to enhance its stability in radiation patterns and high gain over the operating frequencies. The measured results show that a common impedance bandwidth is 80% with standing-wave ratio (SWR) ≤ 1.5 from 1.68 to 3.92GHz, and port-to-port isolation larger than 25 dB within the bandwidth. The measured antenna gains vary from 9.2 to 12 dBi and from 9.2 to 11.8 dBi for port 1 and port 2, respectively. The antenna has nearly symmetrical radiation patterns with low back-lobe radiation both in horizontal and vertical planes, and broadside radiation patterns with narrow beam can also be obtained. [ABSTRACT FROM AUTHOR]

Machine type communication (MTC) systems are a new paradigm in communication systems where machines talk to each other rather than humans. It is expected that more than twenty billion smart devices are deployed around the globe by 2020. The machines talk to each other and communicate with cloud based MTC servers to monitor and control everything around us. Such ubiquitous sensing and actuating require a communication infrastructure. Cellular networks due to their wide coverage are the best candidate for the communication infrastructure. The 3GPP LTE system is the future cellular network. Access class barring (ACB) is introduced by the standard as a solution to alleviate the congestion at the access layer. It works as a persistent probability for network access at the data link layer. In this paper, we consider an MTC system with several devices using LTE system as communication network. Based on the suggestions of the 3GPP standard, we consider uniform activation of devices within a long interval. This activation pattern results in Poisson arrival traffic in each random access channel. Using this arrival traffic pattern, we obtain the ACB factor which maximizes the throughput in the access link. This factor depends on the traffic parameters. Then, we propose a scheme to estimate the traffic parameters. At the end, we propose an algorithm which takes into account practical considerations. We validate our analytical models through extensive simulations. [ABSTRACT FROM AUTHOR]

The global mobile traffic is growing exponentially, and currently more than 90 percent of the internet traffic depends on TCP for reliable transmission. However, it is well known that TCP performs quite poorly over unreliable wireless networks, while its dynamic TCP flow control is sensitive to congestion events and tends to underutilize the available network capacity. Despite these known limitations, the industry believes that significant network performance enhancement can be achieved through TCP optimization, and in particular through solutions centered on Split-TCP. In this article we share a sample of TCP throughput performance measurements after implementing Split-TCP on commercial 4G LTE and 3G networks. Experimental results show that Split-TCP provides average TCP throughput gains on the order of 60 percent over a 4G LTE network and on the order of 5 percent over a 3G network. Furthermore, TCP throughput gains superior to 200 percent were measured for individual TCP connections over the 4G LTE network. We expect such throughput gains to be even greater when advanced radio technologies, such as 5G, are deployed. For these reasons, Split-TCP has the potential to be widely deployed in both current and next generation networks. [ABSTRACT FROM PUBLISHER]

In the Third-Generation Partnership Project (3GPP) Long-Term Evolution (LTE) specifications, several 2-D positioning methods have been proposed to support location-based services (LBSs). It has been shown that the observed time difference of arrival (OTDOA) method provides the best result. With the advent of the fifth-generation cellular systems, 3-D beamforming will be introduced, and 2-D positioning may not be sufficient for future applications. Although the conventional OTDOA method can be used in 3-D positioning, it requires more base stations (BSs) in cooperation and often performs poorly in typical cellular network geometry. In this paper, we propose a novel OTDOA-based method to solve the problems. First, we exploit the sparsity of the wireless channel and propose to use a compressive-sampling-based channel estimation method, which greatly enhances the precision of time-of-arrival (TOA) estimation. Then, we propose a transmit beamforming scheme such that the elevation angle of departure (AOD) can be accurately estimated. Finally, we combine the estimated TOAs and the AOD in the OTDOA scheme to conduct 3-D positioning. With the proposed scheme, the number of BSs required for 3-D positioning remains the same as that of 2-D, and the positioning accuracy greatly outperforms that of the conventional OTDOA method. Simulations show that 90% of the position error can be less than 7 m. [ABSTRACT FROM PUBLISHER]

Although the 3G (UMTS) systems physical-layer performance is still described by both bit-error-rate and block-error-rate, the 4G (LTE) uses exclusively the latter that is at higher protocol layers commonly referred to as frame-error-rate or packet-error-rate of downlink and uplink input data streams. However, the block-error-rate estimation scheme heavily depends on the success rate of negative acknowledgements transport via return channel, and so does not provide trustworthy low values (e.g. around $$10^{-5})$$ . The remaining errors that are not corrected by the physical layer, determine the so-called residual channel and need to be corrected by higher protocols to provide almost errorless application environment. Error rate estimation is therefore important not only in research, development and manufacturing, but also in network operator's environment. However, relationship between the bit-error and the block-error oriented performance metrics is not always a simple one, even at physical layer alone, as well as through higher-protocol layers. In this paper, we benchmark in practice both types of performance metrics for consistency, specifically on an operational microwave link residual channel, bottom upwards to the application-layer, end-to-end perceptual speech quality measurements. [ABSTRACT FROM AUTHOR]

Nowadays users are searching for proper bundle including the whole highlights because all of them are getting to be distinctly mindful of the mobile phone technology change. This causes the fundamental expectation of cellular phone companies to scan for the new technology to outshine their competition. The clients can utilize these applications on their whim through portable correspondence. The aim of this paper is to address the evolution of versatile interchanges from its origin, 1G to 2G, 2G to 3G, 3G to 4G and the newest 4G to 5G. [ABSTRACT FROM AUTHOR]

When incorporating machine-to-machine (M2M) communications into the Third-Generation Partnership Project (3GPP) Long-Term Evolution (LTE) networks, one of the challenges is the traffic overload since many machine-type communication (MTC) devices activated in a short period of time may require access to an evolved node B (eNodeB) simultaneously. One approach to tackle this problem is by using an access class barring (ACB) mechanism with an ACB factor to defer some activated MTC devices transmitting their access requests. In this paper, we first present an analytical model to determine the expected total service time, i.e., the time used by all MTC devices to successfully access the eNodeB. In the ideal case that the eNodeB is aware of the number of backlogged MTC devices, we determine the optimal value of the ACB factor to reduce traffic overload. To better utilize the random access resources shared among human users and MTC devices in LTE networks, we propose to dynamically allocate a number of random access preambles for MTC devices. We further propose two dynamic ACB (D-ACB) algorithms for fixed and dynamic preamble allocation schemes to determine the ACB factors without a priori knowledge of the system backlog. Simulation results show that the proposed D-ACB algorithms achieve almost the same performance as the optimal performance obtained in the ideal case. The proposed D-ACB for dynamic preamble allocation algorithm can reduce both the total time to serve all MTC devices and the average number of random access opportunities required by each MTC device. [ABSTRACT FROM PUBLISHER]

In long-term evolution (LTE) downlink transmission, modified least weighted delay first (MLWDF) scheduler is a quality of service (QoS) aware scheduling scheme for real-time (RT) services. Nevertheless, MLWDF performs below optimal among the trade-off between strict delay and loss restraints of RT and non-RT traffic flows, respectively. This is further worsened with the implementation of hybrid automatic retransmission request (HARQ). As these restraints grow unabated with increasing number of user demands, the performance of MLWDF further reduces. In order to ameliorate this situation, there is a need to directly incorporate the variations in user demands and HARQ implementation as parameters to the MLWDF scheduler. In this work, an improvement to the MLWDF scheduler is proposed. The improvement entails adding two novel parameters that characterise user demand and HARQ implementation. The scheduler was tested using varying three classes of service in QoS class identifiers (QCIs) table standardised by Third Generation Partnership Project for LTE network to characterise different services. It was also tested on the basis of packet prioritisation. The proposed scheduler was simulated with LTE-SIM simulator and compared with the MLWDF and proportional fairness schedulers. In terms of delay, throughput and packet loss ratio; the proposed scheduler increased overall system performance. [ABSTRACT FROM PUBLISHER]

A novel dual-broadband and dual-polarized antenna is proposed in this communication for 2G/3G/LTE base station applications. The antenna comprises of a lower band element and an upper band element which are separated by a ring-shaped baffle. The lower band element employs two pairs of folded dipoles achieving polarization diversity operation at the GSM 850/900 band, and the upper band element uses two crossed dipoles to work at the GSM1800/1900/UMTS and LTE 2300/2500 band. Then, a metal baffle is set in between the lower band and upper band elements for the sake of reducing the mutual coupling and getting good radiation performance. Measured results show that the antenna can get an impedance bandwidth of 23.5% (SWR < 2) from 0.79 to 1 GHz for the lower band and 50.9% from 1.64 to 2.76 GHz for the upper band. High port-to-port isolation can be realized at both the lower and upper bands. Half-power beam widths at horizontal plane of around 69° over the lower band and 73° over the upper band, along with high gain across the entire working band are obtained. An array that consists of four lower band elements and eight upper band elements is also developed. The proposed antenna and its array can be used for multiband base stations in next generation communication systems. [ABSTRACT FROM AUTHOR]

Cellular radio networks continuously evolve to respond the exponential growth in data traffic volume in mobile communications. Active antenna technology contributes to this evolution by introducing vertical sectorization, which splits the horizontal sector into two subsectors with respect to the elevation plane and doubles the number of cells that can be deployed. However, in order to guarantee a reliable and near-optimal operation of vertical sectorization in a system that applies universal frequency reuse, such as LTE-advanced, co-channel interference mitigation is essentially needed. In this article we propose a decentralized self-optimization method that can be used to mitigate the undesirable inter-cell interference by self-tuning the electrical antenna downtilt toward the optimal antenna elevation angle. The performance evaluations for the proposed self-optimization method are carried out for both coordinated and uncoordinated subsector transmission scenarios within the LTE-advanced framework using a dynamic LTE-advanced compliant system level SON simulator. Based on the extensive performance evaluations carried out for a realistic urban scenario, it is found that self-optimization improves the vertical sectorization performance 25 % in terms of virtual load. Furthermore, the performance gain reaches up to 30 % when vertical vectorization is provided with dynamic point selection and muting feature. Therefore, the article concludes that in LTE-advanced networks vertical sectorization can largely benefit from the antenna self-optimization and outperform the traditional horizontal sectorization approach with low algorithmic complexity . [ABSTRACT FROM AUTHOR]

Non-orthogonal transmission, although not entirely new to the wireless industry, is gaining more attention due to its promised throughput gain and unique capability to support a large number of simultaneous transmissions within limited resources. In this article, several key techniques for non-orthogonal transmission are discussed. The downlink technique is featured by MUST, which is being specified in 3GPP for mobile broadband services. In the uplink, grantfree schemes such as multi-user shared access and sparse code multiple access, are promising in supporting massive machine-type communication services. The multi-antenna aspect is also addressed in the context of MUST, showing that MIMO technology and non-orthogonal transmission can be used jointly to provide combined gain. [ABSTRACT FROM PUBLISHER]

Carrier aggregation is a key feature of the 3GPP LTE-Advanced cellular network standard that combines multiple channels to support higher data rates and improve the utilization of fragmented spectrum holdings. This work presents a cellular transmitter capable of transmitting a maximum of four channels simultaneously, two contiguous channels in two bands, with an aggregate bandwidth of up to 80 MHz, supporting a 200 Mbps uplink rate. The transmitter has 8 RF output ports covering the cellular transmit bands within the 572–2025 MHz frequency range. It can support LTE-Advanced Release 12 Cat7, \textHSPA + \textRelease 11, TDSCDMA Release 9, and GSM/EDGE Release 9. The 40 nm CMOS transmitter consumes 22 mA and 27 mA in 3G and LTE modes (at 0 dBm antenna power), respectively, including the PLL, DCXO, and biasing for a single channel. [ABSTRACT FROM PUBLISHER]

Energy efficiency and high reliability are major aspects of modern mobile wireless networks. Therefore, it is a critical step to use power management methods along with fault-tolerant techniques. In this paper, we mathematically investigate the Discontinuous Reception, a power saving mechanism in 3GPP LTE wireless networks, with checkpointing and rollback recovery using a variant of an M/G/1 queue with a modified service time and multiple vacations. Due to the lack of enough storage, the mobile device periodically stores its checkpoint data in a stable fixed server, and rolling back to the latest checkpoint when a transient fault or a wireless link error occurs. Various energy and performance metrics are obtained, while constrained optimization problems are formulated and solved. Extensive numerical results are provided, and give an insight into the operation of the model. [ABSTRACT FROM AUTHOR]

The US Federal Communications Commission (FCC) has mandated wireless network operators and mobile devices to provide accurate location information for E-911. Requirements for time of arrival (TOA) and time difference of arrival (TDOA) measurements have been specified in 3GPP LTE Rel. 9 to ensure accurate user equipment (UE) positioning even under bad conditions (e.g. with channel quickly varying and SNR being as low as −13 dB). To fulfil these requirements, it is vital to accurately estimate the first signal arriving path. In this work, we first derive - without any approximation - the Cramér-Rao lower bound (CRLB) of the LTE TOA and TDOA measurements based on the different pilots, which is shown to be as low as a few metres for SNR = −13 dB. The achievable performance of the LTE system is compared with the FCC and 3GPP requirements, and the impact of mobile multipath channels on the measurements is analysed. Then, we describe practical low-complexity methods for LTE TOA and TDOA measurements with enhanced first arriving path detection. The maximum likelihood based correlation profile is used as detection metric. After grossly determining the signal region by a moving window, three methods, namely, peak detection, SNR-based threshold and adaptive threshold based on noise floor and metric peak value are employed to estimate the first arriving path. Simulation results show that the proposed adaptive threshold-based method can meet all 3GPP requirements under various realistic mobile channels, and can in some cases achieve a performance close to the CRLB. Copyright © 2014 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

The standard for wireless communication of high-speed data in mobile phones and data terminals, called LTE (Long-Term Evolution) and marketed as 4G/LTE, is quickly being adopted worldwide. The security of this type of communication is a crucial factor mainly due to its mobile and wireless nature. This work includes a practical analysis of the SNOW 3G generator used to protect the confidentiality and integrity in LTE communications. In particular, several techniques to perform multiplications and LFSR operations have been studied and implemented on both iOS and Android platforms. The evaluation of those implementations led to some conclusions that could be used to improve the efficiency of future implementations of the standard. [ABSTRACT FROM AUTHOR]

This paper presents a novel smart downlink scheduling scheme to enhance the performance of multimedia transmission over long-term evolution (LTE) networks. LTE represents a promising framework for the next-generation broadband multimedia services because of its significantly increased data rate over 3G cellular networks. However, the current LTE scheduling scheme has largely been designed for general data traffic without adequate consideration of multimedia characteristics. Moreover, the hard handoff (HO) procedure adopted in LTE will further degrade the multimedia services when the mobile user moves from one cell to another. Even with increased data rate, current LTE systems still cannot deliver the expected quality of service (QoS) to the mobile users under various mobility scenarios, especially when the hard HO is evoked. Aiming at overcoming these major challenges, we develop in this paper a QoS-driven smart downlink scheduling scheme for enhanced multimedia transmission over LTE networks. The proposed design shall take the following QoS metrics into consideration: 1) the delay constraint of voice-over-Internet protocol flow; 2) the packet deadline of video flow; and 3) the service degradation induced by the hard HO procedure. We achieve the design objectives by creating three QoS-driven operational control modules: 1) a transmission delay control module to ensure the on-time arrival of various types of multimedia data; 2) an HO control module to warrant continuous multimedia services when the user moves across a cell boundary; and 3) a resource allocation module to strategically map the requested flows to best fit radio resource blocks. The simulation results confirm the performance gain of the proposed scheme. [ABSTRACT FROM AUTHOR]

South Korea has now become one of the world’s leading mobile service markets with the launch of its advanced LTE services; the LTE service subscription rate in Korea has exceeded 50% as of November 2013. This development raises the question of how LTE service subscribers may differ from 3G service subscribers. Within the context of this rapidly changing environment of mobile service markets, this study examines the validity of the traditional determinants of customer satisfaction in data-service oriented mobile communications markets, analyzes the effects of customer satisfaction and switching costs on customer loyalty, and assesses the difference between 3G and LTE subscribers with respect to their determinants of customer loyalty. The results show that there are significant differences between 3G and LTE subscribers while traditional factors such as call quality, data quality, customer support, and price perception are still significant determinants of customer satisfaction. [ABSTRACT FROM AUTHOR]

This paper investigates advanced energy-efficient wireless systems in orthogonal frequency-division multiple access (OFDMA) downlink networks using coordinated multipoint (CoMP) transmissions between the base stations (BSs) in a heterogeneous network (HetNet), which is adopted by Third-Generation Partnership Project (3GPP) Long-Term Evolution (LTE)-Advanced to meet International Mobile Telecommunications-Advanced targets. HetNet CoMP has received significant attention as a way of achieving spectral efficiency (SE) and energy efficiency (EE). Usually, in the literature, the total network power consumption is restricted to the sum of the power consumption of all BSs. The significance of the power consumption of the backhaul links in wireless networks is normally omitted for its trivial effect with respect to that of the radio BSs. For SE and EE analysis of HetNet CoMP, the energy and bandwidth consumption of the backhaul is considered, without which, the investigation remains incomplete. However, SE and EE are design criteria in conflict with each other, and a careful study of their tradeoff is mandatory for designing future wireless communication systems. The EE is measured as “throughput (bits) per joule,” whereas the power consumption model includes RF transmit (radiated), circuit, and backhaul power. Furthermore, a nonideal backhaul model such as a microwave link is also investigated within intra-HetNet-CoMP (inside one cell), where an implementing fiber is not feasible. An intercell interference (ICI) coordination method is also studied to mitigate ICI. At the end, a novel resource allocation algorithm is proposed—modeled as an optimization problem—which takes into account the total power consumption, including radiated, circuit, and backhaul power, and the minimum required data rate to maximize EE. Given an SE requirement, the EE optimization problem is formulated as a constrained optimization problem. The considered optimization problem is transformed into a convex optimization problem by redefining the constraint using cubic inequality, which results in an efficient iterative resource allocation algorithm. In each iteration, the transformed problem is solved by using dual decomposition with a projected gradient method. Simulations results demonstrate how backhaul has a significant impact on total power consumption and the effectiveness of the studied schemes. In addition, the results demonstrate that the proposed iterative resource allocation algorithm converges within a small number of iterations and illustrate the fundamental tradeoffs between SE and EE. Our analytical results shed light on future “green” network planning in advanced OFDMA wireless systems like those envisioned for a fifth-generation (5G) system. [ABSTRACT FROM PUBLISHER]

Assuring quality-of-service (QoS) and guaranteeing effective utilization of resources in a network with heterogeneous traffic is difficult due to the conflicting requirements associated with the different types of traffic. Nevertheless, emerging high-bandwidth third/fourth-generation (3G/4G) technologies, such as Long-Term Evolution (LTE) and LTE-Advanced, are expected to meet the demands of new applications by providing high data rates while simultaneously satisfying each of the individual QoS criteria. The relevant standards recommend single-carrier frequency-division multiple access (SC-FDMA) as the preferred uplink transmission scheme. In this paper, we have formulated the uplink scheduling problem for SC-FDMA-based heterogeneous traffic systems considering both standard specific constraints and individual user QoS requirements. To capture the QoS requirements of different types of traffic, we adopt a utility function that is already used for the downlink operation of code-division multiple-access (CDMA)-based systems. We also consider an opportunity cost function that is based on granular resource utilization to increase the usefulness of our results in practical situations. We have used the dual decomposition method to solve the resulting problem. Given the high computational complexity of the optimal solution, we have also proposed a suboptimal algorithm that is less complex but which offers acceptable performance. In our evaluation of the performance of our proposed uplink scheduling scheme, we assume that the offered traffic is a combination of best effort traffic, traffic with specified delay bounds, and traffic with specified throughput requirements. An extensive set of simulation results demonstrate the efficacy and effectiveness of our scheme compared with existing solutions employed by LTE, which is a representative SC-FDMA-based system. [ABSTRACT FROM PUBLISHER]

In this study, resource allocation problems in uplink transmissions of long term evolution (LTE) networks involving single-carrier frequency division multiple access were addressed and a two-stage process for obtaining solutions was proposed. In the first stage, a buffer-aware (BA) scheme that allocates resources according to users' buffer statuses is used to simultaneously reduce wastage of system resources and improve the throughput of each user. In the second stage, a BA-scheme-based enhanced algorithm is used for considering the delay-sensitive (DS) characteristics of packets. Simulations were conducted to compare the performance of the proposed BA and DS resource allocation algorithm with that of other approaches. The results show that the proposed algorithm can effectively improve the aggregate throughput and reduce both the packet loss rate and average packet delay in comparison with other schemes, thus enhancing the overall uplink efficiency of LTE networks. [ABSTRACT FROM AUTHOR]

In 3G, the server platform of IP multimedia subsystem (IMS) offers multimedia service to the multimedia clients through the exchange of authenticated key agreement (AKA) scheme. Since the IMS service is transmitted over public networks, the server and client of IMS shares a common session-key via the execution of AKA scheme to secure the communication service over a public network. Though there are some identical steps involved in the key authentication Scheme of IMS, the communication efficiencies of IMS server and client are still conciliating. Besides, it is having the issues of insecurity and session compatibility dealt with the real time transport protocol (RTP). To resolve the issues of IMS, this paper proposes three novel schemes: (1) The first scheme is multimedia server-client authentication scheme and its purpose is to mitigate the packet congestion on the networks; (2) The second scheme is traffic on background and its purpose is to analyze the signal congestion, bandwidth consumption and network utilization of the system; and (3) The last one is fault detection index and its purpose is to prevent the SIP vulnerabilities, like bye and invite. In addition, we integrate the proposed and existing authentication schemes, such as EPS-AKA, AP-AKA, UMTS-AKA, X-AKA, S-AKA and so on., in the IMS server and client environments to testify the metrics, namely round trip time, call response time, packet generation, flow analysis, RTP session, network utilization, throughput analysis, bandwidth utilization and flooding attack detection realistically. [ABSTRACT FROM AUTHOR]

The article offers the author's insights regarding the connection of the work of poet and writer Edgar Allan Poe to the Internet. The author discusses the development of the Internet network venture Project Loon by the Internet-related services and products provider Google which relates to Poe's "Balloon Hoax" that aims to provide long-term evolution (LTE) or third-generation (3G) Internet support. The author mentions the Hathi Trust program which manages text datasets.

ABSTRACT A broadband omnidirectional, dual-polarized antenna suitable for 2G/3G/LTE applications is presented in this article. The dual-polarized antenna has a vertically polarized element (VP element) and a horizontally polarized element (HP element). The VP element is a modified discone which can cover the frequency band of 800-2700 MHz (approximately 108%), including the GSM850/900 (824-849/890-960 MHz), DCS 1800 (1710-1880 MHz), PCS 1900 (1850-1990 MHz), UMTS (1920-2170 MHz), LTE 2300 (2305-2400 MHz), and LTE 2500 (2500-2690 MHz). The HP element is composed of a printed dipole array, feeding network, and four pairs of parasitical branches, achieving a wide bandwidth of 64% from 1530 to 2970 MHz (directly overlapping with the higher frequency band of VP element and having some surplus). High isolation larger than 36 dB is achieved in the common operating band because of the insertion of a large clearance. Smooth gain and low cross-polarization levels are also obtained. © 2015 Wiley Periodicals, Inc. Microwave Opt Technol Lett 57:1848-1852, 2015 [ABSTRACT FROM AUTHOR]

Smartphones have significantly changed the traffic pattern usage of mobile subscribers. In addition to the classical file sharing and web browsing usage, social networking applications and access to video content are now a significant percentage of the typical user data traffic consumption. As the change in usage pattern affects the performance of mobile networks, operators need methods to estimate how well the network behaves. The metrics to use for the evaluation of the quality of experience (QoE) are only well documented for traditional applications. In this paper a novel QoE system that automatically captures and processes the metrics needed to evaluate two commonly used applications, the social networking application Facebook and the video download application YouTube, is presented. The system uses a test application developed for Android phones, which report the results to a centralized platform capable of processing and presenting the results in different formats. The system has been used to test those two services over 3G/LTE network technologies. In the case of the YouTube services, performance results show a subjective score very similar for the 3G and LTE because of the automatic adaptation of the video coding rate to the network conditions. Testing of the Facebook application has led to the proposal of a new MOS expression that takes into account the content type being posted, which provides more reasonable MOS estimations than the generic web browsing models available in the literature and commonly used to estimate Facebook QoE. [ABSTRACT FROM AUTHOR]

Device-to-device (D2D) is considered as a promising technique to increase resource utilisation and to provide new application in future wireless networks. This study reviews the standardisation progress of D2D in third-generation partnership project. Three scenarios, in-coverage, partial-coverage and out-of-coverage, are defined. For these scenarios, channel model is obtained by the amendment of existing channel model. The function of D2D operation is divided into three building blocks: synchronisation, discovery and communication. The synchronisation procedure and synchronisation signal/channel are discussed first. Then the design aspects of D2D discovery and communication are discussed in detail, including channel structure design, resource allocation mechanisms, interference management and so on. Future works towards post Rel-12 releases are also briefly outlined. [ABSTRACT FROM AUTHOR]