Time Division-synchronous Code Division Multiple Access Research Articles

A Tutorial on 3GPP Initial Cell Search: Exploring a Potential for Intelligence Based Cell Search

This tutorial guides the reader through the open literature on the aspect of Initial Cell Search (ICS) in both Code Division Multiple Access (CDMA) and Orthogonal Frequency Division Multiple Access (OFDMA) systems perspectives with a special focus on the DownLink (DL), where the ICS represents the very first operational stage of commercial mobile station modem’s always-on mobility. There is no comprehensive up-to-date tutorial of the ICSs encompassing 3G, 4G, and 5G systems. Hence, we review the ICS-related operations which have been proposed for Wideband CDMA (W-CDMA), Time Division-Synchronous CDMA (TD-SCDMA), Long Term Evolution Frequency Division Duplex (LTE-FDD), and Time Division LTE (TD-LTE) from the point of view of 3rd Generation Partnership Project (3GPP) standard and implementation. In the case of TD-SCDMA, there is no in-depth literature illustrating the details of ICS. Therefore, this tutorial aims to fill the related gap in the literature. As an evolution from the operational systems, we also shed light on the ICS being employed in New Radio (NR) system operating at sub-6 GHz and provide insight into interesting and challenging technical issues in millimeter-Wave spectrum bands, which is an ultimate foundation to be deployed in the full-scale NR system. Furthermore, we exemplify entire cell search operations over diverse spectrum bands and elucidate intelligent ways of designing multi-mode mobile station modem in a systematic manner. A taxonomy diagram also classifies three main targets constituting ICS procedures in 3G, 4G, and 5G systems. It is expected that this tutorial is beneficial not only for academic researchers but also for practical modem development engineers.

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.

Design and Implementation of Wireless Sensor Cellular Network Based on Android Platform

the fusion of cellular network and wireless sensor network is the key research problem of Internet of Things (IoT) technology at present. The design and implementation of wireless sensor cellular network based on Android platform is mainly studied. Firstly, wireless sensor network and cellular network, Android platform, cellular network and Wireless Sensor Network (WSN) fusion strategy, and Wireless Sensor Network (WSN) gateway platform are introduced. Then related functions are introduced, mainly including terminal registration management, connection management, authentication management, terminal fault management, and communication message design on the gateway and sensor network side. Finally, related functional tests are conducted. The results show that the designed application layer gateway system can connect the sensor network with the cellular network. Time Division-Synchronization Code Division Multiple Access (TD-SCDMA) and cellular network covers the whole world, while cellular network has been interconnected with the Internet through Access Network Technologies such as General Packet Radio Service (GPRS), The Fourth Generation of Mobile Phone Mobile Communication Technology Standards (4G) and Long Term Evolution (LTE), thus enabling the sensor network to access the Internet anytime and anywhere

Embedded Spectrum Sensor Network Architecture and Transmission Medium Test Based on TCP/IP

Electromagnetic spectrum monitoring that fully covers spectrum resources guarantees the orderly use of key technologies. However, existing monitoring equipment and methods cannot satisfy the increasing demand. A feasible solution for this problem is a wireless sensor network that is developed using a wireless self-organized network technology for a new type of distributed information system. For the wireless spectrum-monitoring network used by software, this study analyzes the operating system and hardware platform and then tests the physical transport layer under different transmission rates. Factors that may affect transmission performance are also investigated. A two-layer network model is eventually used based on the network to adapt to the requirements and the minimum transmission rate. The first layer uses cable, wideband code-division multiple access (CDMA), and time-division synchronous CDMA; the second layer network uses Wi-Fi/cable. This two-layer network model combines two heterogeneous networks, thereby enabling perception among nodes and gateway nodes. The management center can smooth the data transmission process. To perform several tasks simultaneously, we design our own two layers at the application layer protocol, namely, transmission protocol and data. The two-stage ad-hoc network process, the working principle, and the implementation method of each network application layer module are analyzed. The new spectrum sensor network structure exhibits low power consumption, low cost, as well as distributed and self-organization characteristics. It can guarantee the safety of data transmission with a good transmission rate.

Exposure to 3G mobile phone signals does not affect the biological features of brain tumor cells.

BackgroundThe increase in mobile phone use has generated concerns about possible risks to human health, especially the development of brain tumors. Whether tumor patients should continue to use mobile telephones has remained unclear because of a paucity of information. Herein, we investigated whether electromagnetic fields from mobile phones could alter the biological features of human tumor cells and act as a tumor-promoting agent.MethodsHuman glioblastoma cell lines, U251-MG and U87-MG, were exposed to 1950-MHz time division-synchronous code division multiple access (TD-SCDMA) at a specific absorption rate (maximum SAR = 5.0 W/kg) for 12, 24, and 48 h. Cell morphologies and ultra-structures were observed by microscopy and the rates of apoptosis and cell cycle progression were monitored by flow cytometry. Additionally, cell growth was determined using the CKK-8 assay, and the expression levels of tumor and apoptosis-related genes and proteins were analyzed by real-time PCR and western blotting, respectively. Tumor formation and invasiveness were measured using a tumorigenicity assay in vivo and migration assays in vitro.ResultsNo significant differences in either biological features or tumor formation ability were observed between unexposed and exposed glioblastoma cells. Our data showed that exposure to 1950-MHz TD-SCDMA electromagnetic fields for up to 48 h did not act as a cytotoxic or tumor-promoting agent to affect the proliferation or gene expression profile of glioblastoma cells.ConclusionsOur findings implied that exposing brain tumor cells in vitro for up to 48 h to 1950-MHz continuous TD-SCDMA electromagnetic fields did not elicit a general cell stress response.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-1996-7) contains supplementary material, which is available to authorized users.

An Improved Channel Estimation in a TD-SCDMA System Based on the Threshold of Detect Energy and its Performance Analysis

B. Steiner estimator used in the time-division synchronous code-division multiple access (TD-SCDMA) system is a low cost estimator. The precision of the estimated channel impulse responses (CIRs) is affected by noises in the channel, which result in worse performance of the estimation. For the reason that there are many threshold processing algorithms based on Steiner algorithm, the optimal threshold value becomes a crucial factor. In this paper, based on statistical information of channel in the data field, an improved channel estimation algorithm is proposed by detecting energy of CIR's tap in time-domain, and the amplitude of estimated channel impulse response is adjusted by a gain coefficient. Simulation results prove the validity of the proposed technique for channel estimation good performance. Additionally, it is shown that the improved estimators outperform traditional channel estimators.

A comprehensive survey of TDD-based mobile communication systems from TD-SCDMA 3G to TD-LTE(A) 4G and 5G directions

TDD (Time Division Duplex) is one of the two duplex modes. TD-SCDMA (Time Division Synchronous CDMA) is the first TDD-based cellular mobile system which is commercialized in wide area and large scale and TD-SCDMA is also the first cellular mobile system which adopted smart antenna technology (also called as beamforming). As the long term evolution of TD-SCDMA, TD-LTE(A) (Time Division-Long Term Evolution, and TD-LTE Advanced) introduced OFDM (Orthogonal Frequency Division Multiplexing) and enhanced smart antenna technology together with MIMO (Multiple Input Multiple Output), which are adopted by LTE FDD (Frequency Division Duplex) either. It is indicated that TD-SCDMA and TD-LTE(A) have opened a sustainable utilization era of TDD and smart antenna technologies in the wireless mobile communication. This paper aims to present a systematic introduction to TDD-based mobile communications from TD-SCDMA to TD-LTE and beyond, with particular focuses on TDD key technologies, principles of TDD cellular mobile systems, TDD evolution path, and future TDD 5G directions. The comparisons between TDD and FDD are also included. We hope that this paper will provide a comprehensive overview of TDD technology upgrade and its standard evolution, and serve as a valuable reference for research on 5G mobile communication systems. It is believed that TDD will play more important role in 5G.

Performance Evaluation of the Joint Detection with Channel Estimation Error

In previous B. Steiner channel estimation algorithm adopted in Time DivisionSynchronous Code Division Multiple Access (TD-SCDMA) system, but there are some errors in estimated channel due to noise. However, due to using the short training sequences available, the resulting estimation of the channel and detected data suffer from unavoidable errors. In this paper, we analyze the effect of channel estimation error on joint detection and evaluate the performance of TD-SCDMA systems with channel estimation error. The simulation results are consistent with the theory analysis.

The Rules Have Changed: A Case Study of Chinese Government Support of Local Technologies

Beginning in the late 1990s, the Chinese government began to understand the negative effects of relying on external technology transfer, the country's key technology sourcing policy since the 1980s: local firms were becoming so dependent on external technology that they were not developing effective internal technology capabilities to sustain their competitiveness. In response to this realization, government agencies such as the Ministry of Science and Technology and the National Development and Reform Commission began to work to promote indigenous innovation. The culmination of these efforts came in June 2003, when the Chinese central government invited more than 2,000 experts to participate in a two-year study of the country's science and technology policy. Based on that work, the results of which were released in 2005, the Chinese central government decided in 2006 to make promoting indigenous innovation a national strategy (PRC State Council 2006). Although mobile technology was an early target for government efforts to nurture indigenous development efforts (Lou 2008), firms did not react quickly to those efforts. One of the three international standards for mobile communications, TD-SCDMA (time division-synchronous code division, multiple access), was based mainly on technologies developed by Chinese firm Datang Telecom Technology & Industry Group (Datang); TD-SCDMA was proposed as a candidate standard in 1998 and adopted by the International Telecommunications Union (ITU) in May 2000. Thus, TD-SCDMA was an indigenous innovation with international applications. The government provided various kinds of support to reduce both technology and market uncertainties, intended to increase firms' confidence in adopting TD-SCDMA. However, multinational firms, displayed a lack of sensitivity to the Chinese government's intention to promote indigenous innovation and took a wait and attitude toward TD-SCDMA. As a result, these firms lost their dominant market position in China. The story of multinationals' response to government efforts to support TD-SCDMA offers important lessons for MNEs attempting to build a presence in China. Government Support of TD-SCDMA The Chinese government used four strategies to support indigenous development of TD-SCDMA technology: * Leveraging the size of China's market to support TD-SCDMA, * Supporting development of TD-SCDMA through frequency spectrum assignments, * Providing financial and technical support for development of TD-SCDMA technology, and * Supporting TD-SCDMA by deploying government power. The sheer size of the Chinese telecommunications market gave the government leverage to influence multinationals' choice of technologies. The Chinese telecom equipment market is the largest in the world; once the market opened to multinationals, those firms rapidly came to dominate the market, nearly shutting out local firms. Clearly, this was not a market they wanted to lose. At one point, when some multinational firms tried to block the acceptance of TD-SCDMA as an international standard, the Minister of the Information Industry invited top managers of these firms in China to come to the Ministry, where he delivered a clear message: the Chinese government wanted to see TD-SCDMA treated the same as other candidates in the mobile communications standards selection process. The implication was that multinationals that did not support TD-SCDMA would be shut out of China. The support of multinational firms played a critical role in the eventual acceptance of TD-SCDMA as an international standard. The government further supported the development and adoption of TD-SCDMA by allocating favorable frequencies to the technology. The frequency spectrum allocation for 3G mobile telecommunications, announced in 2002 by the Ministry of the Information Industry, assigned 155MHz to TD-SCDMA and 180MHz total to WCDMA and CDMA2000, the other two international 3G standards, combined--just 90 MHz for each of the two alternate standards. …

Scrambling Code Planning in TD-SCDMA Cellular Systems

Scrambling code planning (SCP) for time-division synchronous code-division multiple-access (TD-SCDMA) systems is a challenging issue due to the poor cross correlations between the spreading codes generated by cell-specific scrambling codes. In this paper, a novel SCP algorithm is proposed. Intercell interference is modeled as a function not only of the cross correlations between spreading codes but of the radio propagation conditions and traffic distributions as well. The cross correlation of spreading codes is analyzed, and the concept of the scrambling code family is proposed to simplify the code planning process. The proposed algorithm facilitates the assignment and selection of scrambling codes. Numerical results shows that the proposed algorithm can achieve a much lower intercell interference than the existing SCP algorithms.

TDD-based mobile communication solutions for high-speed railway scenarios

Mobile communication solutions for highspeed railway scenarios aim at providing seamless coverage, high system capacity and a high data rate for end users, which in turn face the challenges of Doppler frequency shift, penetration loss, mobility management and system capacity planning. Because the scarcity of frequency resources and increasing wireless broadband requirements have become very serious problems worldwide, increasing attention has been focused on time-division duplexing based technology, on which we focus in this article. Time-division synchronous code-division multiple access based and time-division Long Term Evolution based solutions are introduced with appropriate technology analysis. The experimental results of TD-SCDMA-based solutions in the Shanghai maglev high-speed network environment and the simulation results of TD-LTE-based solutions are presented. Finally, to improve performance, we discuss an enhanced solution based on mobile relays with performance evaluation, which is considered as a more comprehensive solution for high-speed railway scenarios.

LTE/LTE-A signal compression on the CPRI interface

The Centralized, Cooperative, Cloud Radio Access Network (C-RAN) is a next-generation wireless access network architecture based on centralized processing, collaborative radio, and real time cloud infrastructure. In this architecture, different access technologies (Global System for Mobile Communications (GSM)/Time Division Synchronous Code Division Multiple Access (TD-SCDMA)/Wideband Code Division Multiple Access (WCDMA)/Long Term Evolution (LTE)) can be supported on the same hardware platform in a baseband pool system, which can largely reduce system costs. Long Term Evolution (LTE) and Long Term Evolution-Advanced (LTE-A), which are based on Orthogonal Frequency Division Multiplexing (OFDM) and multiple input multiple output (MIMO) technologies, are regarded as the main wireless access technologies in the evolution from 3G to 4G. A variety of novel technologies such as multi-antenna MIMO, carrier aggregation (CA), and coordinated multipoint have been introduced in LTE/LTE-A to improve system performance, especially in the C-RAN architecture. However, one of the technical challenges for the C-RAN architecture is the fiber bandwidth required for data transmission between the remote radio unit (RRU) and the baseband unit (BBU). We propose using a low-latency baseband signal compression algorithm to solve this problem by reducing the fiber data rate. Using the characteristics of the LTE signal data, we remove the redundancy in the spectral domain. We also leverage block scaling in conjunction with using a linear or nonlinear (non-uniform) quantizer to minimize quantization error. This algorithm effectively reduces the amount of data transmitted between the BBU and RRU, and facilitates the deployment of LTE in the C-RAN architecture. We verified the robustness of the algorithm via simulations and lab tests. The proposed algorithm yields good system performance at a 1/2 compression rate and at a 1/3 compression rate in a practical propagation environment.

A SiGe RF Power Amplifier for TD-SCDMA Application

A SiGe HBT power amplifier for Time Division Synchronous Code-Division Multiple-Access (TD-SCDMA) application with a single positive 3.3V supply has been demonstrated in this paper by adopting a newly proposed usage of the bonding wire. Though the emitter bonding wire may decrease the power gain, it can also decrease the effect of the knee voltage, thus increase the efficiency of the power amplifier. The post-simulation result shows that it can exhibit a linear gain of 29dB, output power of 30dBm, power-added efficiency of 38.49%, and -43dBc suppression at the second harmonic for TD-SCDMA application.

Analysis and Simulation of Mobile Terminal Dual-Unit Smart Antenna

In this paper, we set up the model of downlink for Time Division synchronous Code Division Multiple Access (TD-SCDMA), and present link level simulation to TD-SCDMA mobile terminal smart antenna system. By carrying on performance simulation in system bit error rate between dual-unit antenna and single-unit antenna, we can validate the advantage of dual-unit smart antenna. Besides, we analysis the mobile terminal smart antenna may influenced by many factors, such as distance of two antenna, moving speed, the number of multi-path and user and so on, solve the contradiction between miniaturization of mobile terminal smart antenna and independence between antenna, and provide a valuable design reference to commercialize the limited frequency spectrum resource.

Doppler Shift Estimation for TD-SCDMA System over Railway Environments

In this paper, a new Doppler shift estimator is proposed for Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) over railway environments. Different from other existing methods, which commonly assume that the fading channel coefficients are available for the Doppler estimators, the proposed estimator is developed based on the signals which contain unknown frequency selective fading channel coefficients, unknown Rice factor and random receiver noise; it contains three steps. The statistical properties of the training symbols which are called near independent identically distributed (i.i.d.) training sequences, i.e., midamble, are first analyzed. Afterwards, by the help of a training sequence, the second-order and fourth-order statistics of the received signals are calculated. Then, by exploiting these statistical results, the Doppler shift estimator is obtained. The proposed estimator employs a smoothing function with corrective factor. By optimizing the corrective factor, an accuracy solution is acquired within the Doppler shift range of possibilities. Simulation results indicate that the proposed estimator is greatly reliable and effective to estimate Doppler shift up to 400 Hz.

The Wireless Network Positioning Strategies Basing on Mobile Terminal

With the continuous development of terminal technologies, the use of mobile terminals is becoming more and more diverse. Many value-added services brought by such applications gradually become to be the firm's new profit opportunity. The location itself has great value; with the display of electronic map or with the support of geographic information database, a variety of information can be shown, tracked and handled. Such location-based services (LBS) is widely used in the field of public wireless data, and mobile location services is recognized as the most attractive wireless data value-added business in 3G network. This paper discusses three positioning standards of the 3GPP first; and then combined with the existing GSM/GPRS cellular radio communication network, it mainly gives specific positioning implementation strategies of single base station in the TD-SCDMA (Time Division Synchronous Code Division Multiple Access) system.

Singular Value Decomposition Rank-Deficient-Based Estimators in TD-SCDMA Systems

This paper presents a new joint channel estimation method for Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) systems based on a Singular Value Decomposition (SVD) reduced-rank technique. The system capacity is increased by increasing the highest number of users in one time slot. The additional channel estimation processing required for the increasing number of users is solved by adopting the reduced-rank technique, which estimates a limited number of parameters that are needed to describe the channel matrix and reduce the dimensionality of this matrix. Simulation results prove the validity of the proposed reduced-rank technique for channel estimation accuracy enhancing. Additionally, it is shown that the detectors based on the reduced-rank estimators outperform traditional channel estimators, contributing to 7.8 and 6.9 dB BER performance improvements for indoor and vehicular channels, respectively.

Frequency estimation for the downlink of the TD-SCDMA system over frequency flat Rician fast fading channels

In this paper, a new frequency estimation scheme is proposed for the downlink of Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) system over frequency flat Rician fast fading channels. The proposed algorithm exploits the synchronous downlink sequence of the downlink pilot time slot in the sub-frame, and takes account of the case where the carrier frequency offset (CFO) and the Doppler shift coexist. The new approach first presents the second-order and fourth-order statistics of the signals which contain unknown CFO, unknown Rician fading coefficients with the Doppler shift, and additive white Gaussian noise. Then, by flexible parameters setting and concrete mathematical operations for above statistics, a new closed-form expression for frequency estimation (the CFO and the Doppler shift) is derived. The simulation results are finally provided to illustrate the accuracy and reliability of the proposed method within the expectative frequency estimation range.

A security authentication scheme in machine‐to‐machine home network service

AbstractMachine‐to‐machine (M2M) techniques have significant application potential in the emerging internet of things, which may cover many fields from intelligence to ubiquitous environment. However, because of the data exposure when transmitted via cable, wireless mobile devices, and other technologies, its security vulnerability has become a great concern during its further extending development. This problem may even get worse if the user privacy and property are considered. Therefore, the authentication process of communicating entities has attracted wide investigation. Meanwhile, the data confidentiality also becomes an important issue in M2M, especially when the data are transmitted in a public and thereby insecure channel. In this paper, we propose a promising M2M application model that connects a mobile user with the home network using the existing popular Time Division‐Synchronous Code Division Multiple Access (TD‐SCDMA) network. Subsequently, a password‐based authentication and key establishment protocol is designed to identify the communicating parties and hence establish a secure channel for data transmissions. The final analysis shows the reliability of our proposed protocol. Copyright © 2012 John Wiley & Sons, Ltd.

Interference Analysis of TD-SCDMA System and CDMA2000 System

Abstract—In this paper, the feasibility of co-channel coexistence of Time Division- Synchronous Code Division Multiple Access（TD-SCDMA）and Code Division Multiple Access 2000（CDMA2000）systems operating in a macro cell environment is investigated. The deterministic analysis and simulation method are used to evaluate the performance compromising of both systems. Based on a more efficient calculation scheme, a novel deterministic equation is proposed and used to provide a better interpretation of the relationship between aggressor and victim in the interference system. The evaluation and simulation results show consistency with the corresponding experiment results. Furthermore, the interference characteristics of Omni-antenna and smart antenna in TD-SCDMA and CDMA2000 are compared, providing an important guideline to reduce the interference of two systems.