Digital Mobile Communication Research Articles

The creation of standards for global mobile communication: GSM and UMTS standardization from 1982 to 2000

GSM and UMTS are the leading standards for digital mobile communications with 5.4 billion users and nearly 90 percent world market share. Success factors for this development were the advanced and timely available system standards developed until the end of the 1990s in Europe. In the pioneer period (1982 to 1992) Phase 1 of the digital GSM standard was developed for the first GSM networks. GSM Phase 2 completed in 1995 provided a platform for an unlimited feature evolution. The GSM Phase 2+ program (1993 to 2000) provided new services, better speech quality and enhanced data services and made GSM a system of generation 2.5. An evolution to the Third Generation based on the GSM core network evolution and a new radio subsystem was conceived in the period from 1996 to 2000. A consensus between Europe, Japan and the North American GSM community on this concept was achieved. The standardization work required an effective global working structure. This was also necessary for the GSM work. To cover these needs, the Third Generation Partnership Project (3GPP) was created to develop globally applicable technical specifications. 3GPP exists since the end of 1998 and has developed a series of specification releases for 3G and a new 4G system (LTE).

The Remote Monitoring Platform Based on GSM/WCDMA

Aimming at the demand of China's remote medical monitoring, a scheme of a human health remote monitoring system based on ZigBee technology and ARM chip is designed. In this system, the signal from human is transmitted to the mobile terminal equipment --PDA through the ZigBee wireless network. The physiological signal detected is passed to the remote monitoring platform using GSM/WCDMA digital mobile communication system, which realizes the remote medical monitoring for patients at home. The experiment results show that the system has a stable performance, good mobility and can achieve real-time monitoring to the patient's health status.

Research on Communication Automation with Design and Implementation of FTP Based on Serv-U

With the rapid development of network technology, communication automation system is widely used. It includes cabling system, broadband network system, mobile phone coverage system, cable and digital communication system. Use of the network is one of the functions of communication automation, and FTP (File Transfer Protocol) is one of the widely used protocols in the Internet. Based on the network platform, people use FTP service to transfer files and share information resources. The paper discusses the construction, working principle and access methods of FTP site. According to the security problems of FTP service, the paper researches on communication automation and proposes the security strategy of FTP technology. Combined with the engineering example, it introduces the concrete steps and methods of setting up FTP server based on server software Serv-U. Using FTP technology, it realizes allocation and rational use of information resources and also constructs a reliable, efficient, unified information platform. The FTP system runs normally.

Advanced Information Technologies in Future Computing Environments

Information Technology (IT) would stand for all of continuously evolving and converging technologies, including digital convergence, multimedia convergence, intelligent applications, embedded systems, mobile and wireless communications, bio-inspired computing, grid and cloud computing, semantic web, user experience and HCI, security and trust computing and so on, for satisfying our ever-changing needs. In past three decades, IT influenced and changed every aspect of our lives and our cultures. Without various IT-based applications, it would be difficult to process information efficiently, to communicate information conveniently, and to keep information stored securely. In future computing environments (cloud and cluster computing, pervasive and ubiquitous computing, etc.), IT will play a very important role in convergence of computing, communication and all other computational sciences and applications. IT will also influence the future world’s various areas, including science, engineering, industry, business, law, politics, culture, medicine, and so on. This special issue is to foster the dissemination of state-of-the-art research in all advanced information technologies in future computing environments, including their models, services, and novel applications associated with their utilization. This special issue is aimed to solicit research results on the following topics of interest, but not limited: • Hybrid Information Technology • High Performance Computing

Multiple optimized online support vector regression for adaptive time series prediction

Data-driven prognostics based on sensor or historical test data have become appropriate prediction means in prognostics and health management (PHM) application. However, most traditional data-driven prognostics methods are off-line which would be seriously limited in many PHM systems needed on-line predicting or real-time processing. Furthermore, even in some on-line prediction algorithms such as Online Support Vector Regression (Online SVR) and Incremental learning algorithm, there are conflicts and trade-offs between prediction efficiency and accuracy. Therefore, in different PHM applications, prognostics algorithms should be on-line, flexible and adaptive to balance the prediction efficiency and accuracy. An on-line adaptive data-driven prognostics strategy is proposed with five various optimized on-line prediction algorithms based on Online SVR. These five algorithms are improved with kernel combination and sample reduction to realize higher precision and efficiency. These algorithms can achieve more accurate results by data pre-processing and model optimization, moreover, faster operating speed and lower computational complexity can be obtained by optimization of training process with on-line data reduction. With these different improved Online SVR methods, varies of prediction with different precision and efficiency demands could be fulfilled by an adaptive strategy. To evaluate the proposed prognostics strategy, we have executed simulation experiments with Tennessee Eastman (TE) process. In addition, the prediction strategies are also applied and evaluated by traffic mobile communication data from China Mobile Communications Corporation Heilongjiang Co., Ltd. Experiments and test results prove its effectiveness and confirm that the algorithms can be effectively applied to the on-line status prediction with increased performance in both precision and efficiency.

WiMax2 PKMv2 암호화 계층의 검증 및 성능 평가 테스트베드의 구축

PKMv2 security protocol was adopted by the WiMax2 mobile internet communication standard. A base station and a mobile station protect communication data using key based encryption according to the PKMv2 protocol. Consequently, each development of a base station and/or mobile station includes implement of the PKMv2 protocol, and the station must qualifies various interoperable tests. Furthermore, communication bandwidth of the station can be limited by the encryption module when the station implemented based on a low-performance processor. Thus, a correspondence measurement of the encryption module must be carried on the target processor. In this paper, we implement a testbed which affords throughput measurement as well as the interoperable tests by PKMv2.

A Comparative Study of Three TDMA Digital Cellular Mobile Systems (GSM, IS-136 NA-TDMA and PDC) Based On Radio Aspect

As mobile and personal communication services and networks involve providing seamless global roaming and improve quality of service to its users, the role of such network for numbering and identification and quality of service will become increasingly important, and well defined. All these will enhance performance for the present as well as future mobile and personal communication network, provide national management function in mobile communication network and provide national and international roaming. Moreover, these require standardized subscriber and identities. To meet these demands, mobile computing would use standard networks. Thus, in this study the researcher attempts to highlight a comparative picture of the three standard digital cellular mobile communication systems: (i) Global System for Mobile (GSM) -- The European Time Division Multiple Access (TDMA) Digital Cellular Standard, (ii) Interim Standard-136 (IS-136) -- The North American TDMA Digital Cellular Standard (D-AMPS), and (iii) Personal Digital Cellular (PDC) -- The Japanese TDMA Digital Cellular Standard.

Reliability Models of GSM-R Redundant Network on High-Speed Railway

As a dedicated digital mobile communication system designed for railway application, GSM-R must provide reliable bidirectional channel for transmitting security data between trackside equipments and on-train computer on high-speed railways. To ensure the safety of running trains, redundant network architecture is commonly used to guarantee the reliability of GSM-R. Because of the rigid demands of railway security, it is important to build reliability mathematical models, predict the network reliability and select a suitable one. Two common GSM-R wireless architectures, co-sited double layers network and intercross single layer network, are modeled and contrasted in this paper. By calculating the reliabilities of each reliable model, it is clear that more redundant the architecture is, more reliable the system will be, the whole system will bear a less failure time per year as the benefit. Meanwhile, as the redundancy of GSM-R system raises, its equipment and maintenance will cost much, but the reliability raise gently. From the standpoint of transmission system interruption and network equipment failure, the reliability of co-sited double layer network architecture is higher than the intercross single layer one, while the viability and cost of the intercross redundant network is better than co-sited one in natural disasters such as flood and lightning. Taking fully into account reliability, viability and cost, we suggest that intercross redundant network should be chosen on high-speed railway.

Frequency/time hopping sequence sets with optimal partial Hamming correlation properties

Frequency hopping/time hopping(FH/TH) sequences have found wide applications in various modern FH/TH spread spectrum communications, such as digital cellular mobile communication, short-range wireless communication, personal communication, and multi-user radar, sonar systems. In order to evaluate the goodness of FH/TH sequences design, the periodic Hamming correlation function is used as an important measure. Usually, the length of correlation window is shorter than the period of the chosen FH/TH sequence, so the study of the partial Hamming correlation of FH/TH sequence is particularly important. In this paper, a new class of FH/TH sequence sets with good partial Hamming correlation properties is proposed and investigated. The construction of new FH/TH sequence sets is based upon the generalized m-sequence and generalized Gordon-Mills-Welch sequence over a polynomial residue class ring. It is shown that new FH/TH sequence sets are optimal with respect to the partial Hamming correlation bound.

Disruptive or Sustaining Impact of WLAN Hotspots?

In this paper the impact of WLAN-technologies on mobile data communications in the case of the incumbent telecommunications firms and entrants in the Western European hotspot markets based on a disruptive innovation perspective is described and analysed. The main proposition to be analysed is whether or not WLAN has developed disruptive potential for the incumbents in this market so far. The results imply that incumbents and new entrants have taken advantage of the opportunity provided by WLAN technologies and the public hotspot market in Western Europe. Although the market success of both types of players varies between the countries analysed, in most Western European countries the incumbents dominate the public hotspot market. This result suggests a predominantly sustaining impact of WLAN technologies on the incumbents based on a country basis. However, the sustaining impact of WLAN is weaker if alternative business models, such as free or community network hotspots, are taken into account.

Impact of Group Mobility on QoS of Mobile WiMAX (IEEE 802.16e) Network with CBR Application

IEEE 802.16e is a wireless broadband network standard aimed at providing robust, high data rate mobile communication. With a modified IEEE 802.16e standard, it becomes possible to provide robust group mobility in battle zone or emergency operations that require centralized control. In these situations, the group mobility issues are very important to support the military and emergency applications, in which multiple mobile stations (MSs) could move in the same direction with short separations as a group. In this paper we designed a system to analyze the performance of mobile WiMAX network (IEEE 802.16e) based on QoS parameters (Throughput, Average jitter and Average end-to-end delay) in group mobility environment having different group size, while CBR application is going on. Keywords: - Group mobility, CBR, IEEE 802.16e, Group size, QoS

Blind channel estimation and discrete speed tracking in wireless systems using independent component analysis with particle filtering

For high data rate multiple-input multiple-output (MIMO) systems, a joint blind channel estimation and data recovery algorithm is presented for where the relative speed of the transmit/receive terminals may change. This changing speed is called manoeuvering. The blind technique is based on non-stationary independent component analysis with a generalised exponential density function to separate each source signal, and it uses particle filtering to track the time-varying channel. The presented technique also uses a hard decision switching block which adaptively selects between discrete speeds of a manoeuvering terminal. The speed can be therefore tracked within a mobile data communication link, that is, by using only the received data information signal. The performance is evaluated by simulation and is compared with optimal coherent detection as benchmark. A large degradation in system error performance is observed if the switching block is disabled within the algorithm, confirming its advantage. Moreover, to assess the impact of the presented blind channel estimation on system error performance more directly, a fair comparison with a known blind technique based on Kalman filtering and two known pilot-aided systems is presented with the assumption of non-manoeuvering terminals. Improved performance is observed using the presented technique.

Block Edge Mask의 대역 외 방출 기준치 유도 및 간섭 영향 분석

최근 무선 멀티미디어 통신 수요의 팽창에 따른 주파수 부족 문제를 해결할 수 있는 방안으로 기술 및 서비스 중립성을 가지는 개방형 주파수 할당 방식의 도입이 예상되면서 여기에 적합한 새로운 간섭 관리의 모렐 및 기준 설정이 요구된다. 본 논문에서는 우리나라의 이러한 새로운 간섭 관리를 위한 모델로 여러 가지 후보 방식들을 고려한 결과, Block Edge Mask (BEM) 방식을 가장 적합한 모델로 선정한다. 그리고 BEM의 기준치 설정에 따른 간섭 영향을 알아보기 위해 디지털 방송 전환 여유 대역에 LTE 시스템의 사용을 가정하여, 이종 시스템인 디지털 지상파 텔레비전 방송 (DTV) 서비스와 LTE 이동통신 서비스의 경계 대역에서의 BEM의 대역 외 방출(Out-of-band emission) 기준을 유도하고 보호 대역의 설정에 따른 영향을 알아본다. As an introduction of an open spectrum allocation approach with technology and service neutrality is expected as a way to solve problems of frequency shortage due to the expansion of demand for wireless multimedia communications, recently, the new management model of interferences and its standard setting are required. In this paper, as a model for this new interference management considering several candidates, Block Edge Mask(BEM) approach is chosen as the most appropriate model. And to investigate the effects of interference resulting from the standard setting of BEM, assuming the use of LTE systems in the Digital Dividend, BEM out-of-band baseline in the boundaries between digital terrestrial television (DTV) service and LTE mobile communications services which are heterogeneous systems for analysis is derived and the effect of setting guard band is analyzed.

Iterative Source–Channel Decoding With Reduced Error Floors

Audio-visual source encoders for digital mobile communications extract parameters that-due to delay and complexity constraints-exhibit some residual redundancy. This residual redundancy can be exploited by iterative source-channel decoding (ISCD) to improve the robustness against transmission noise by performing soft parameter detection as part of the decoding process. Systems employing ISCD at the receiving end often exhibit an observable error floor. While this error floor can be tolerated in some cases, it is often desirable to perfectly reconstruct the source codec parameters. In this paper, we explain the reasons for the error floor and propose two solutions for realizing ISCD systems with optimized error floor performance while maintaining the desired near-capacity waterfall behavior. All approaches aim at optimizing the distance properties of the (redundant) mapping of bit patterns to the source codec parameters. In some cases, especially if small quantizer code books are employed, good mappings cannot be found-in this case, the novel multi-dimensional bit mapping allows to reduce the error floor after decoding.

Parallel LDPC decoding using CUDA and OpenMP

Digital mobile communication technologies, such as next generation mobile communication and mobile TV, are rapidly advancing. Hardware designs to provide baseband processing of new protocol standards are being actively attempted, because of concurrently emerging multiple standards and diverse needs on device functions, hardware-only implementation may have reached a limit. To overcome this challenge, digital communication system designs are adopting software solutions that use central processing units or graphics processing units (GPUs) to implement communication protocols. In this article we propose a parallel software implementation of low density parity check decoding algorithms, and we use a multi-core processor and a GPU to achieve both flexibility and high performance. Specifically, we use OpenMP for parallelizing software on a multi-core processor and Compute Unified Device Architecture (CUDA) for parallel software running on a GPU. We process information on H-matrices using OpenMP pragmas on a multi-core processor and execute decoding algorithms in parallel using CUDA on a GPU. We evaluated the performance of the proposed implementation with respect to two different code rates for the China Multimedia Mobile Broadcasting (CMMB) standard, and we verified that the proposed implementation satisfies the CMMB bandwidth requirement.

Nodes and Gravity in Virtual Space

In 1996 John Perry Barlow made his now infamous Declaration of Independence for Cyberspace. In this the cyberlibertarian ethos was laid out: We must declare our virtual selves immune to your sovereignty, even as we continue to consent to your rule over our bodies. We will spread ourselves across the Planet so that no one can arrest our thoughts. Since that date much has changed. The work of a number of US cyberpaternalist philosophers such as Jonathan Zittrain, Jack Goldsmith, Joel Reidenberg, Yochai Benkler and most famously Lawrence Lessig has illustrated the fundamental weaknesses in Barlow s (and therefore cyberlibertarianism s) basic premises. This does not mean though that because one can be controlled in cyberspace, one ought to be controlled or even one will be controlled. The distinction is between the ability to control and the effectiveness and legitimacy of control mechanisms. It is this distinction which is at the heart of network communitarianism and which is likely to come more to the fore as the network is replaced with the cloud, always on data, augmented reality and mobile data communications. The key issue for regulators now is the strength of the network and the ability of regulators to control within the network. Building upon previous regulatory designs of the author and taking account of nodal governance theory as developed by Clifford Shearing and Julia Black, this paper aims to demonstrate that the key to building effective and legitimate regulation in the virtual space is to recognise and harness key nodal connections and key nodes themselves. It will demonstrate how the cybercommunity functions as both a community and a group of individual nodes and will seek to develop a theory of regulatory gravity in which the relative communicative power of various nodes may be modelled to take account of the effectiveness and legitimacy of a regulatory intervention.

Analysis of Queue Estimation Methods Using Wireless Magnetic Sensors

Four queue estimation methodologies were studied with wireless magnetic sensors installed on a single-lane loop on-ramp. Queue length estimation based on (a) occupancy measurements at the ramp entrance, (b) vehicle counts at the on-ramp entrance and exit, (c) speed measurements at the ramp entrance, and (d) vehicle reidentification were considered. These queue estimation methods were evaluated with available raw and processed sensor data retrieved from the test site through mobile data communication and downloaded from a server. The accuracy and reliability of the queue estimation methods were studied with ground truth data obtained from video. Discrepancies between inconsistent sensor and ground truth data were identified and further analyzed with raw data coming directly from the vehicle detection system at the on-ramp. Each of the methods analyzed had deficiencies that needed to be taken into account and compensated for if they were to be used for applications that involved ramp metering with accurate queue control. The worst performance of the queue estimation methods was observed when the on-ramp was under congestion (queue extends around or beyond the ramp entrance). On the basis of the observations at the on-ramp test site, it was also possible to point out some of the main factors that affect the performance of the queue estimation methods.

Applications of Reed-Solomon codes in mobile digital video communications systems

In this paper, we analyse a decoding algorithm, which corrects both erasures and errors for Reed-Solomon (RS) codes based on the Euclidean algorithm together with the Berlekamp-Massey (BM) algorithm. We present and discuss the implementation of RS codes in the digital video broadcasting (DVB) standards and give a brief review of the new DVB-H standard. Analysis and simulation of the symbol error rate (SER) versus the output SER for the Reed-Solomon code used for the multi-protocol encapsulation-forward error correction (MPE-FEC) block in DVB-H has been conducted.

Design and Flight Test Results of Robust Attitude Controller for the ETS-VIII Spacecraft

AbstractThis paper reports the flight test results of robust attitude controller for Engineering Test Satellite VIII (ETS-VIII) spacecraft. The main mission of ETS-VIII is to support next-generation mobile digital communications, and for this purpose it is equipped with two large deployable antenna reflectors and a pair of large solar paddles that rotate around the pitch axis. For the spacecraft, the authors have proposed and demonstrated several control methods based on the advanced control theories for the linear parameter varying multi-input multi-output system. The aim is to develop a baseline for future controller design technology for this class of satellite instead of existing classical PID control laws. This paper describes the on-orbit experiment results and compares these controllers performance.

Heterogeneous Remote Visualization Framework for Ubiquitous Product Development Activities

Design office, as is known today, is a workplace where various experts gather and develop products. Traditionally, the trend in engineering product development has been to use desktop computers, virtual reality systems and other systems and devices placed in specific workplace locations. Clearly, these sorts of stationary support tools are desirable because they matchup the product development methodological frameworks that have prevailed over the past several decades. With the availability of a wide spectrum of improved mobile and wireless communication technologies coupled with increased network bandwidth and enhanced software for mobile data-communication networks, design researchers now have new opportunity of exploring and coming up with concrete recommendations on how these technologies should be utilized in product development. Therefore, the work reported in this paper aimed at investigating how to take advantage of these technologies and how the product developers can benefit from the capabilities provided by both portable and non-portable information and communication devices. The focus was specifically on the challenge of visualization of product data and models remotely. The main characteristic requirements for a remote product visualization environment have been formulated and used as the basis for creation of a generic framework. It has been shown that the proposed framework meets some of the key requirements.