Time Division Long Term Evolution Research Articles

Multi-modal interaction using time division long-term evolution (TD-LTE) for space designing exhibition

Multi-modal interaction using time division long-term evolution (TD-LTE) for space designing exhibition

No Alteration Between Intrinsic Connectivity Networks by a Pilot Study on Localized Exposure to the Fourth-Generation Wireless Communication Signals.

Neurophysiological effect of human exposure to radiofrequency signals has attracted considerable attention, which was claimed to have an association with a series of clinical symptoms. A few investigations have been conducted on alteration of brain functions, yet no known research focused on intrinsic connectivity networks, an attribute that may relate to some behavioral functions. To investigate the exposure effect on functional connectivity between intrinsic connectivity networks, we conducted experiments with seventeen participants experiencing localized head exposure to real and sham time-division long-term evolution signal for 30 min. The resting-state functional magnetic resonance imaging data were collected before and after exposure, respectively. Group-level independent component analysis was used to decompose networks of interest. Three states were clustered, which can reflect different cognitive conditions. Dynamic connectivity as well as conventional connectivity between networks per state were computed and followed by paired sample t-tests. Results showed that there was no statistical difference in static or dynamic functional network connectivity in both real and sham exposure conditions, and pointed out that the impact of short-term electromagnetic exposure was undetected at the ICNs level. The specific brain parcellations and metrics used in the study may lead to different results on brain modulation.

Rainfall estimation using measurement report data from time-division long term evolution networks

Accurate rainfall measurement is essential for flood forecasting, effective water resources management, agriculture, etc. Many traditional rainfall monitoring methods, such as rainfall gauges, weather radars, and satellites, have been developed. Recently, a rainfall retrieval algorithm based on the radio connection between one telephone tower and another has seen widespread use across countries as it does not require any deployment procedures or costs. However, because underground fibre-optic cable networks have been widely introduced and deployed between telephone towers, usage of rainfall retrieval algorithms has reduced. Measurement report (MR) data from time-division long term evolution (TD-LTE) networks for providing instructions to the user terminal has the potential to estimate rainfall owing to the impact of rainfall-based attenuation on MR data. We present an analysis of MR data collected during the local flood season over 2 months (May and August 2019) in Huizhou city, southern China. Comparisons between estimated and observed rainfall exhibit promising results. Rainfall estimation from MR data is a potential alternative/complementary rainfall estimation method, as well as having use in runoff simulations, with acceptable accuracy (>0.8); this is particularly relevant in the context of disappearing microwave links between telephone towers in cellular communication networks. The rainfall estimation method proposed herein can also be implemented in rarely gauged or ungauged areas for flood simulation.

Switched Low-Noise Amplifier Using Gyrator-Based Matching Network for TD-LTE/LTE-U/Mid-Band 5G and WLAN Applications

This paper presents a triple-band low-noise amplifier (LNA) fabricated using a 0.18 μm Complementary Metal-Oxide-Semiconductor (CMOS) process. The LNA uses a double-peak load network with a switched component to accomplish the triple-band operation. Moreover, noise reduction using a substrate resistor to ameliorate the noise performance is presented. Noise reduction of 1.5 dB can be achieved at 2.5 GHz without additional dc power and extra manufacturing costs. An input matching technique is realized simultaneously using a gyrator-based feedback topology. The triple-band LNA can be realized by using a dual-band input network with a switched matching mechanism. The target frequencies of the triple-band LNA are 2.3–2.7 GHz, 3.4–3.8 GHz, and 5.1–5.9 GHz, covering the operating frequency bands of time-division long-term evolution (TD-LTE), mid-band Fifth-generation (5G), LTE-unlicensed (LTE-U) band, and Wireless LAN (WLAN) technology. The measured power gains and noise figures at 2.5, 3.5, and 5.2 GHz are 12.3, 15.3, and 13.1 dB and 2.3, 2.2, and 2.6 dB, respectively.

An ESD and Interference-Robust Protection Circuit for Cascode Low-Noise Amplifier in CMOS-SOI Technology

In this paper, we propose a double diode network including an additional stacked diode, which provides robustness against Electrostatic discharge (ESD) and high-frequency interference signals. The proposed stacked diode in the conventional double diode network protects the integrated circuit from instantaneous voltage events by providing an additional current path to the double diode network. Also, it can structurally minimize the parasitic capacitance generated in the diode. The general operating principle and limitation of the conventional double diode network for ESD events and high-frequency interference signals were analyzed and simulated. For experimental verification, a cascode LNA with inductive source degeneration was designed in a 130nm CMOS Silicon-on-insulator (SOI) process for the time-division long-term evolution (TD-LTE) application at the coexistence band. The LNA with the proposed double diode network provides a noise figure of 1.08 dB and a small-signal gain of 18.7 dB at 2.65 GHz (Band 41). And it was measured to be able to protect the internal circuit at 2000 V HBM event, and the RF performances were not affected even with a high-frequency interference signal close to 30 dBm.

Correction of Radio Wave Propagation Prediction Model Based on Improved Seagull Algorithm in Tunnel Environment

In the urban rail transit (URT) environment, the radio wave propagation prediction model and communication system planning are very important. However, due to the complexity of the tunnel propagation environment, the current prediction model can not fully cover the radio wave propagation process in the tunnel. In this paper, the propagation mechanism area is divided based on the segmentation approach. Different propagation models are used for different propagation mechanism areas to predict path loss more quickly and accurately. To improve the accuracy of the prediction model, this paper proposes an improved seagull optimization algorithm (ISOA). First, to address the shortcomings of the seagull optimization algorithm (SOA) such as easy premature convergence and slow convergence speeds, two improved methods of random search and periodic disturbance are proposed. Then, in order to verify the effectiveness and feasibility of the improved algorithm, the benchmark function is used to test the optimization performance of the ISOA and gray wolf optimization, the SOA, and particle swarm optimization. The results show that the optimization performance of ISOA is the most significant. Finally, the ISOA is used to fit and correct the continuous wave test data for a rectangular tunnel and an arch tunnel. The results show that the corrected propagation model has a higher degree of fit with the measured data than the single standard propagation model (SPM) model. The modified propagation model thus has guiding significance for the deployment of time-division long-term (TD-LTE) evolution networks in the tunnel environment.

Novel multiband ring coupler based on notch filter

A novel method for designing a multiband rat-race ring coupler based on a notch filter is proposed. This method realizes dual-, tri-, quad-, penta-, … band characterizes of coupler using the same structure, two additional branches. So, it has three advantages: (a) simple structure even the number of working bands more than four; (b) achieving the different numbers of working bands with just one structure; (c) useful for almost any kind of wideband passive components because it views them as black boxes. Three prototypes, a tri-band ring coupler (Global System for Mobile Communications 0.9 GHz, Digital Communication System 1.8 GHz, Industrial Scientific Medical 2.45 GHz), a quad-band ring coupler (Time Division Long-Term Evolution 2.3 GHz, Satellite C-Band Downlink 3.8 GHz, Aeronautical Radio Navigation 4.3 GHz, and Satellite C-Band Uplink Applications 6.3 GHz) and a penta-band ring coupler (Frequency Division Long-Term Evolution [LTE-FDD] 0.9, 1.4, 1.8, 2.3, and 2.6 GHz), are simulated and measured. They all use the same structure but different parameters of the added branch. The results validate the functionality of the coupler. The method of designing multiband devices in this study can be used for other passive devices, and the structure is simple.

Decoupling of Antennas With Adjacent Frequency Bands Using Cascaded Decoupling Network

This communication presents a novel decoupling device called a cascaded power dividing decoupling network (C-PDDN). It is cascaded with two antennas operating in adjacent or even contiguous frequency bands to reduce the mutual coupling. To achieve high isolations at n desired frequency points, an n-order C-PDDN can be accordingly designed. Each order PDDN consists of two power dividers (PDs), two sections of transmission lines, and one reactive component. Explicit design formulas are presented to calculate the design parameters of the C-PDDN to meet the required isolation criteria. To validate the decoupling concept, a two-order C-PDDN is designed and applied to a testing array that consists of two base-station dipole antennas, one of which serves the time-division long-term evolution (2300-2400 MHz) and the other for wireless fidelity system (2400-2483.5 MHz). The simulated and measured results demonstrate that the proposed two-order C-PDDN could decrease the mutual coupling by over 20 dB, verifying the decoupling methodology.

Three Decades of 3GPP Target Cell Search through 3G, 4G, and 5G

This survey provides the reader with the open literature on the detailed operational scenarios of Target Cell Search (TCS) in both 3G and 4G systems, with a particular emphasis on the DownLink (DL). There is no completely latest survey of the TCS scenarios. Therefore, we examine the TCS-involved solutions which have been chosen for Wideband-Code Division Multiple Access (W-CDMA), Time Division-Synchronous Code Division Multiple Access (TD-SCDMA), Long-Term Evolution Frequency Division Duplex (LTE-FDD), and Time-Division Long-Term Evolution (TD-LTE). Especially for TD-SCDMA, there is no concrete literature demystifying the details of TCS scenario. Accordingly, this survey aims for repairing the associated crack in the literature. Moreover, as a recent evolution from the operational systems, we also focus on the TCS scenario which can be exploited in New Radio (NR) systems operating at both sub-6 GHz and millimeter-Wave (mmW) spectrum bands. A taxonomy diagram is also provided to classify relevant target cell search scenarios in 3G, 4G, and 5G as well as followed by those in inter-Radio Access Technologies (RATs). In a nutshell, our endeavors definitize the first comprehensive survey on the TCS progress tailored to the evolution of commercial mobile communication systems over three decades. It is worth mentioning that this survey is also informative for engineers and researchers to design practical mobile station modem.

Turbo Decoder Design based on an LUT-Normalized Log-MAP Algorithm.

Turbo codes have been widely used in wireless communication systems due to their good error correction performance. Under time division long term evolution (TD-LTE) of the 3rd generation partnership project (3GPP) wireless communication standard, a Log maximum a posteriori (Log-MAP) decoding algorithm with high complexity is usually approximated as a lookup-table Log-MAP (LUT-Log-MAP) algorithm and Max-Log-MAP algorithm, but these two algorithms have high complexity and high bit error rate, respectively. In this paper, we propose a normalized Log-MAP (Nor-Log-MAP) decoding algorithm in which the function max* is approximated by using a fixed normalized factor multiplied by the max function. Combining a Nor-Log-MAP algorithm with a LUT-Log-MAP algorithm creates a new kind of LUT-Nor-Log-MAP algorithm. Compared with the LUT-Log-MAP algorithm, the decoding performance of the LUT-Nor-Log-MAP algorithm is close to that of the LUT-Log-MAP algorithm. Based on the decoding method of the Nor-Log-MAP algorithm, we also put forward a normalization functional unit (NFU) for a soft-input soft-output (SISO) decoder computing unit. The simulation results show that the LUT-Nor-Log-MAP algorithm can save about 2.1% of logic resources compared with the LUT-Log-MAP algorithm. Compared with the Max-Log-MAP algorithm, the LUT-Nor-Log-MAP algorithm shows a gain of 0.25~0.5 dB in decoding performance. Using the Cyclone IV platform, the designed Turbo decoder can achieve a throughput of 36 Mbit/s under a maximum clock frequency of 44 MHz.

Establishment and optimization of packet transport network core bearer network oriented to long-term evolution business

The modern telecommunication has come into the Long-Term Evolution (LTE) era. The whole transmission network gradually has evolved to the IP network. The overall network organization is likewise becoming more and more similar to the metropolitan data network. A mobile Packet Transport Network (PTN) transmission network construction is investigated. The specific bearing requirements of time division long-term evolution (TD-LTE) are analyzed. The topology structures of L3 and L2/L3 and the equipment applications in different network levels of the PTN network are discussed. The existing problems concerning the circuit scheduling, disaster tolerance requirement, security connection and business pressure are analyzed in detail. Their corresponding optimization strategies are presented. Finally, the network level having a clear, robust and complete coverage is reached. It proves that the optimized network can meet the third level of the disaster tolerance international standard SHARE 78.

A Novel Radio Resource Optimization Method for Relay-Based Unmanned Aerial Vehicles

Unmanned aircraft systems (UASs) have attracted worldwide attention in recent years because of their potential applicability in a multitude of fields such as environmental monitoring and the communication provisioning environment. These applications enable data to be remotely collected from distant places through unmanned aerial vehicles (UAVs) equipped with communication devices. However, the communication range of a single UAV is limited because of the restrictions of the wireless transceiver as a result of the payload limitation. Therefore, UASs consisting of relay-based UAVs in which data are transferred via multiple UAVs have been studied to achieve long-distance communication with a high throughput. The time division long-term evolution advanced (TD-LTE-A) relaying technique may be applicable to UASs as it offers a reasonable solution. However, this technique is currently ineffective for UASs due to the limitation caused by its frame configuration. To alleviate this issue, in this paper, we propose a method to optimize radio resources based on the TD-LTE-A frame structure, which is capable of realizing efficient relay communication. Our proposed method considers a flexible frame configuration and updates cycle of control information to overcome the shortcoming of the conventional scheme. The effectiveness of the proposed radio resource optimization is demonstrated through simulation under varying environments.

The QoS Indicators Analysis of Integrated EUHT Wireless Communication System Based on Urban Rail Transit in High‐Speed Scenario

Nowadays, in urban rail transit systems, train wayside communication system uses Wireless Local Area Network (WLAN) as wireless technologies to achieve safety‐related information exchange between trains and wayside equipment. However, according to the high speed mobility of trains and the limitations of frequency band, WLAN is unable to meet the demands of future intracity and intercity rail transit. And although the Time Division‐Long Term Evolution (TD‐LTE) technology has high performance compared with WLAN, only 20 MHz bandwidth can be used at most. Moreover, in high‐speed scenario over 300 km/h, TD‐LTE can hardly meet the future requirement as well. The equipment based on Enhanced Ultra High Throughput (EUHT) technology can achieve a better performance in high‐speed scenario compared with WLAN and TD‐LTE. Furthermore, it allows using the frequency resource flexibly based on 5.8 GHz, such as 20 MHz, 40 MHz, and 80 MHz. In this paper, we set up an EUHT wireless communication system for urban rail transit in high‐speed scenario integrated all the traffics of it. An outdoor testing environment in Beijing‐Tianjin High‐speed Railway is set up to measure the performance of integrated EUHT wireless communication system based on urban rail transit. The communication delay, handoff latency, and throughput of this system are analyzed. Extensive testing results show that the Quality of Service (QoS) of the designed integrated EUHT wireless communication system satisfies the requirements of urban rail transit system in high‐speed scenario. Moreover, compared with testing results of TD‐LTE which we got before, the maximum handoff latency of safety‐critical traffics can be decreased from 225 ms to 150 ms. The performance of throughput‐critical traffics can achieve 2‐way 2 Mbps CCTV and 1‐way 8 Mbps PIS which are much better than 2‐way 1 Mbps CCTV and 1‐way 2 Mbps PIS in TD‐LTE.

Gene-Sequencing-Based Indoor Localization in Distributed Antenna System

In the indoor distributed antenna system (DAS), base station transmits signals with even power via the distributed antennas. Thus, single reference signal received power (RSRP) from the receiver will result in accurate localization. In response to this compelling problem, we utilize the pedestrian dead reckoning, which is based on consecutive signals in collected RSRP sequences as the template sequences, to achieve high-performance location estimation. Specifically, the main idea of the proposed localization algorithm is calculating the correlation between the on-site sequence and each pre-constructed template sequence, which is labeled with human movement coordinates. Then, the prediction location is considered as the template sequence label that is with the largest approximation to the on-site sequence. Experiments are conducted with real time division long-term evolution signals in indoor DAS, and the corresponding experimental results demonstrate that the proposed approach can not only solve the problem of positioning in DAS, but also provide satisfactory localization accuracy.

Link level performance comparison between LTE V2X and DSRC

Applications of VANETs (Vehicular Ad hoc Networks) have their own requirements and challenges in wireless communication technology. Although regarded as the first standard for VANETs, IEEE 802.11p is still in the field-trial stage. Recently, LTE V2X (Long-Term Evolution Vehicular to X) appeared as a systematic V2X solution based on TD-LTE (Time Division Long-Term Evolution) 4G. It is regarded as the most powerful competitor to 802.11p. We conduct link level simulations of LTE V2X and DSRC (Dedicated Short-Range Communication) for several different types of scenarios. Simulation results show that LTE V2X can achieve the same BLER (Block Error Ratio) with a lower SNR (Signal Noise Ratio) than DSRC. A more reliable link can be guaranteed by LTE V2X, which can achieve the same BLER with lower receiving power than DSRC. The coverage area of LTE V2X is larger than that of DSRC.

Analysis and prediction of 100 km-scale atmospheric duct interference in TD-LTE networks

Atmospheric ducts are horizontal layers that occur under certain weather conditions in the lower atmosphere. Radio signals guided in atmospheric ducts tend to experience less attenuation and spread much farther, i.e, hundreds of kilometers. In a large-scale deployed TD-LTE (Time Division Long Term Evolution) network, atmospheric ducts cause faraway downlink wireless signals to propagate beyond the designed protection distance and interfere with local uplink signals, thus resulting in a large outage probability. In this paper, we analyze the characteristics of ADI atmospheric duct interference (Atmospheric Duct Interference) by the use of real network-side big data from the current operated TD-LTE network owned by China Mobile. The analysis results yield the time varying and directional characteristics of ADI. In addition, we proposed an SVM (Support Vector Machine)-classifier based spacial prediction method of ADI by machine learning over combination of real network-side big data and real meteorological data. Furthermore, an implementation of ADMM (Alternating Direction Methods of Multipliers) framework is proposed to implement a distributed SVM prediction scheme, which reduces data exchange among different regions/cities, maintains similar prediction accuracy and is thus of a more practical use to operators.

LTE-V: A TD-LTE-Based V2X Solution for Future Vehicular Network

Diverse applications in vehicular network present specific requirements and challenges on wireless access technology. Although considered as the first standard, IEEE 802.11p shows the obvious drawbacks and is still in the field-trial stage. In this paper, we propose long-term evolution (LTE)-V as a systematic and integrated V2X solution based on time-division LTE (TD-LTE) 4G. LTE-V includes two modes: 1) LTE-V-direct and 2) LTE-V-cell. Comparing to IEEE 802.11p, LTE-V-direct is a new decentralized architecture which modifies TD-LTE physical layer and try to keep commonality as possible to provide short range direct communication, low latency, and high reliability improvements. By leveraging the centralized architecture with native features of TD-LTE, LTE-V-cell optimizes radio resource management for better supporting V2I. LTE-V-direct and LTE-V-cell coordinate with each other to provide an integrated V2X solution. Performance simulations based on sufficient scenarios and the prototype system with typical cases are presented. Finally, future works of LTE-V are envisioned.

On the Co-Existence of TD-LTE and Radar Over 3.5 GHz Band: An Experimental Study

This paper presents a pioneering study based on a series of experiments on the operation of commercial Time-Division Long-Term Evolution (TD-LTE) systems in the presence of pulsed interfering signals in the 3550-3650 MHz band. TD-LTE operations were carried out in channels overlapping and adjacent to the high power SPN-43 radar with various frequency offsets between the two systems to evaluate the susceptibility of LTE to a high power interfering signal. Our results demonstrate that LTE communication using low antenna heights was not adversely affected by the pulsed interfering signal operating on adjacent frequencies irrespective of the distance of interfering transmitter. Performance was degraded only for very close distances (1-2 km) of overlapping frequencies of interfering transmitter.

TD-LTE virtual cells: An SDN architecture for user-centric multi-eNB elastic resource management

This paper introduces mechanisms and algorithms for managing efficiently the resources of Time-Division Long Term Evolution (TD-LTE) networks in a flexible manner enabling (i) dynamic frame alternation at each evolved Node B (eNB) and (ii) forming virtual cells, which allow diverse resource utilization to users residing within regions that can utilize resources from multiple eNBs. Our approach leverages the benefits of Software Defined Network (SDN) paradigm for monitoring network resource utilization and allowing applications or services to request resources. The resources requested by the applications or services can be allocated on-demand by adjusting the Time Division Duplex (TDD) frames in different regions of the geographical area being considered. This can be accomplished by creating virtual cells in the overlapping regions that can customize service for the residing users. A simulation study has been carried out to elaborate the benefits of this approach and the performance enhancements in comparison with the conventional TD-LTE configurations are presented. The results indicate significant performance gains of around 30%–35% considering both UL/DL directions respectively.

Compact dual‐element inverted‐F MIMO antenna system with enhanced isolation

ABSTRACTA compact multiple‐input‐multiple‐output (MIMO) inverted‐F antenna system for time division‐long term evolution (TD‐LTE) E band, 3.50‐GHz worldwide interoperability for microwave access, and 5.20‐GHz wireless local area network with enhanced isolation is proposed. The proposed MIMO antenna system consists of two identical inverted‐F antenna elements operating in the 2.32–2.37/3.40–3.62/5.12–5.29 GHz frequency bands at the reflection coefficient level below −10 dB. The edge‐to‐edge distance between the two antenna elements is only 0.1 mm. The high isolation is achieved by mirror symmetrical orientation of the two antenna elements on the different side of the FR4 substrate and replacing part of the substrate with pieces of copper to connect the ground planes together to form a common ground. The size of the proposed antenna system has the dimensions of 53.00 mm 10.95 mm. The measured isolation between the two antenna elements exceed 19.23 dB, 14.56 dB and 23.74 dB at the aforementioned operation bands, respectively. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:363–368, 2016