Guo L.,Beijing University of Posts and Telecommunications |
Guo L.,China Academy of Telecommunication Research |
Wang Y.,Tsinghua National Laboratory for Information Sciences and Technology |
Du Z.,Tsinghua National Laboratory for Information Sciences and Technology |
And 2 more authors.
IEEE Antennas and Wireless Propagation Letters | Year: 2014
A compact uniplanar printed dual-antenna for laptop computers is proposed. The dual-antenna, consisting of two symmetric antenna elements and a protruded ground with an embedded T-shaped slot, is printed on a single-layer printed circuit board with a size of only 9 × 40 mm2. The antenna element is a coupled-fed loop antenna with a size of only 9 × 7 mm 2. The protruded ground with the embedded T-shaped slot reduces the mutual coupling within two frequency bands. The working mechanism is analyzed in detail for deep understanding. A prototype shows that the measured-10-dB impedance bandwidths are 190 MHz (2.38-2.57 GHz)/1.82 GHz (4.34-6.16 GHz), and the measured mutual couplings are lower than-18/-20 dB at the 2.4-and 5.2/5.8-GHz WLAN bands, respectively. The measured gains and efficiencies are better than 4.1/4.1 dBi and 65%/54% at the 2.4-and 5.2/5.8-GHz WLAN bands, respectively. © 2014 IEEE.
Li Y.,Beijing University of Posts and Telecommunications |
Peng M.,Beijing University of Posts and Telecommunications |
Wang W.,Beijing University of Posts and Telecommunications |
Zhang X.,China Academy of Telecommunication Research
IEEE Wireless Communications and Networking Conference, WCNC | Year: 2013
Power allocation for orthogonal frequency division multiplexing (OFDM) based two-way relay link in cognitive relay networks is discussed in this paper. Two secondary source nodes exchange their information through a secondary relay node by using amplify-and-forward two-way relaying strategy. The goal of power allocation is to maximize the sum data rate of the secondary system subject to the constraint that the aggregation interference of the secondary system on the primary system does not exceed the given threshold. In addition, individual node power constraint is applied for both secondary source nodes and the secondary relay node. We solve the optimization problem by using dual decomposition approach, and further propose a distributed power allocation algorithm. Numerical results demonstrate the advantage of the proposed algorithm over uniform power allocation. Besides, power-constrained as well as interference-constrained regions are shown in our numerical experiments. © 2013 IEEE.
Zhang X.,China Academy of Telecommunication Research |
Peng M.,Beijing University of Posts and Telecommunications |
Ding Z.,Newcastle University |
Wang W.,Beijing University of Posts and Telecommunications
IEEE Transactions on Wireless Communications | Year: 2012
There has been a growing interest in analog network coding, which can improve system throughput and spectrum efficiency significantly in wireless systems. Two-way relay scenario is considered in this paper, where the base station (BS) and the relay are both equipped with multiple antennas, and each of K user equipments (UEs) in the cell has a single antenna. An advanced multi-user scheduling scheme is proposed for the analog network coded two-way relay channel, where UEs and BS exchange information via the relay node during two time slots. Because each UE with single antenna has poor transmission and reception capability, the scheduling scheme is carefully designed to decrease multi-user interference and optimize beamforming gain from BS to relay. Analytical results of sum rate and outage probability have been developed to demonstrate that the multi-user diversity gain can be achieved by the proposed scheme. Meanwhile, the user fairness of the proposed scheme is on the same order as that of round robin (RR), and the computation complexity only increases linearly with the number of users in the serving cell. Monte-Carlo simulation is conducted to exhibit the performance gains from the proposed scheduling scheme. Results show that the proposed channel correlation based user selection scheme outperforms existing traditional scheduling schemes significantly, even when the cellular user payload is low. © 2012 IEEE.
News Article | December 14, 2016
FREMONT, Calif.--(BUSINESS WIRE)--The Optical Internetworking Forum (OIF) is winding down a six-week long interoperability demo on the Transport Application Programming Interface (T-API) standard from the Open Networking Foundation (ONF). The demo started in mid-October and will conclude in early December. Participants executed a multi-domain path selection and recovery test plan with intra-lab and inter-lab testing across multiple global carrier labs. The results of the demo will be shared in three invitation-only read-out events at China Telecom, Telefonica and Verizon for participating companies. A public readout event will take place at the OFC Conference in Los Angeles, March 21, 2017. “China Telecom is pleased to once again host the Global Transport SDN demo in our lab in Beijing. Transport API for SDN is an important technology to simplify the maintenance and increase the efficiency of networks, which matches China Telecom’s CTNet2025 network re-architecting target.” said Mr. Chengliang Zhang, Vice President, China Telecom Beijing Research Institute. “This demo provided interesting and important results and key findings and was worthwhile for China Telecom to participate.” “Telefonica is happy to have participated in the OIF SDN demo and to have hosted vendors in our labs,” said Mr. Juan Pedro Fernández-Palacios, Head of Transport Telefónica GCTO. “The work to demonstrate interoperability for transport API among multiple vendors is important for the industry as a means to unlock and reap the expected benefits of SDN.” “Shaping next-generation technology through discussion and collaboration is key to commercial SDN deployment. Verizon’s role as a host carrier for OIF’s interoperability testing of the global SDN T-API underscores our commitment to solving problems that will help evolve the efficiencies needed in the next-generation network,” said Glenn Wellbrock, director, transport network architecture, design and planning, Verizon. A technical white paper and an executive summary of the demo will be available in early February. The OIF and the ONF are partnering to lead the industry toward the wide scale deployment of commercial SDN by testing key Transport Application Programming Interfaces (T-API). The interoperability test and demonstration, managed by the OIF, will address multi-layer and multi-domain environments in global carrier labs. The testing builds on the 2014 demo which was based on prototype T-APIs and helped advance transport SDN standardization. Additional use cases based upon the API standards will be clarified during the testing and defined through OIF implementation agreements to provide a common set of requirements. Global Carrier participants hosting the interoperability testing include China Telecom, China Unicom, SK Telecom, Telefonica and Verizon. Participating vendors include ADVA Optical Networking, Ciena, Coriant, Huawei Technologies Co., Ltd., Infinera, Juniper Networks, NEC Corporation, Sedona Systems, and SM Optics. Consulting carriers include Orange and TELUS. Academic and/or research institution participants include China Academy of Telecommunication Research (CATR) and Centre Tecnològic de Telecomunicacions de Catalunya (CTTC). Additional information can be found at http://www.oiforum.com/meetings-and-events/2016-oif-sdn-t-api-demo/ The OIF facilitates the development and deployment of interoperable networking solutions and services. Members collaborate to drive Implementation Agreements (IAs) and interoperability demonstrations to accelerate and maximize market adoption of advanced internetworking technologies. OIF work applies to optical and electrical interconnects, optical component and network processing technologies, and to network control and operations including software defined networks and network function virtualization. The OIF actively supports and extends the work of national and international standards bodies. Launched in 1998, the OIF is the only industry group uniting representatives from across the spectrum of networking, including many of the world’s leading service providers, system vendors, component manufacturers, software and testing vendors. Information on the OIF can be found at http://www.oiforum.com.
News Article | February 15, 2017
FREMONT, Calif.--(BUSINESS WIRE)--The Optical Internetworking Forum (OIF) conducted a six-week long global testing of the Transport Application Programming Interface (T-API) standard from the Open Networking Foundation (ONF). The OIF managed the multi-location demonstration which started in mid-October 2016 and concluded in December 2016. Vendor participants executed a multi-domain path selection and recovery test plan with intra-lab and inter-lab testing across five carrier labs located in Asia, Europe and North America. A technical white paper on the demonstration is available to download here. “As operators move from SDN PoCs and lab trials into commercial deployments, lack of interoperability between the SDN controllers and the orchestration layer above has quickly become the biggest technical barrier for many operators,” said Sterling Perrin, principal analyst, Heavy Reading. “Building a standardized northbound interface and successfully testing interoperability across different vendors and different networks – as the OIF has demonstrated – is a major step forward in addressing the northbound interface challenge and bringing SDN architectures to wide-scale commercial use.” The Optical Internetworking Forum (OIF) and the Open Networking Foundation (ONF) are leading the industry toward the wide scale deployment of commercial SDN by testing key Transport Application Programming Interfaces (T-API). The interoperability test and demonstration, managed by the OIF, addresses multi-layer and multi-domain environments in the following carrier labs; China Telecom, China Unicom, SK Telecom, Telefonica and Verizon. These carriers defined real world use cases including multi-domain orchestration of services delivered through Ethernet, OTN and optical switching. Carriers and vendors demonstrated how Virtual Network Functions (VNF) and SDN configured connectivity are combined to deliver service life cycle management. Participating vendors include ADVA Optical Networking, Ciena, Coriant, Huawei Technologies Co., Ltd., Infinera, Juniper Networks, NEC Corporation, Sedona Systems, and SM Optics. Consulting carriers include Orange and TELUS. Academic and/or research institution participants include China Academy of Telecommunication Research (CATR) and Centre Tecnològic de Telecomunicacions de Catalunya (CTTC). Additional information can be found here. Participants in the OIF Transport SDN interoperability event also submitted a proof of concept demo proposal to ETSI NFV. The proposal, “Mapping ETSI-NFV onto Multi-Vendor, Multi-Domain Transport SDN”, was accepted and details are located here. The open demonstration of NFV concepts in a Proof of Concept (PoC) helps to build industrial awareness and confidence in NFV as a viable technology. Proofs of Concept also help to develop a diverse, open, NFV ecosystem. Results from PoCs may guide the work in the NFV ISG by providing feedback on interoperability and other technical challenges. “Being able to dynamically establish connectivity between Virtual Network Functions enables carriers to provide greater service agility and reduce opex,” said Jonathan Sadler, of Coriant and the OIF Interoperability chair. “Integrating multiple technologies using transport SDN further enables the right connectivity mechanisms used for service delivery. Having this demonstration recognized by ETSI NFV provides building blocks for the development of future SDN-WAN.” “SK Telecom is delighted that we have successfully tested interoperability using SK Telecom's Transport Infra Orchestrator and T-API. The test proves that standardized T-API can be used to control multi-layer, multi-vendor transport network infrastructure in an integrated manner,” said Park Jin-hyo, Senior Vice President and Head of Network Technology R&D Center at SK Telecom. “SK Telecom will continue to make efforts to develop 5G and network virtualization technologies to realize Network as a Service (NaaS).” The OIF facilitates the development and deployment of interoperable networking solutions and services. Members collaborate to drive Implementation Agreements (IAs) and interoperability demonstrations to accelerate and maximize market adoption of advanced internetworking technologies. OIF work applies to optical and electrical interconnects, optical component and network processing technologies, and to network control and operations including software defined networks and network function virtualization. The OIF actively supports and extends the work of national and international standards bodies. Launched in 1998, the OIF is the only industry group uniting representatives from across the spectrum of networking, including many of the world’s leading service providers, system vendors, component manufacturers, software and testing vendors. Information on the OIF can be found at http://www.oiforum.com.
Sun C.,Beihang University |
Sun C.,China Academy of Telecommunication Research |
Yang C.,Beihang University
IEEE Transactions on Vehicular Technology | Year: 2013
Two-way relaying is more spectral efficient than one-way relaying and is expected to consume less transmit power than one-way relaying to achieve the same data rate. However, when circuit power consumption is also taken into account, two-way relaying may not be more energy efficient, particularly when the bits to be transmitted from two source nodes have different numbers. To always offer high energy efficiency (EE), we propose a hybrid relay strategy, which conveys bidirectional messages with both one-way and two-way relaying. To maximize its EE, we jointly optimize the number of bits and transmission time allocated to the one- and two-way relaying stages to minimize the overall energy consumption, including the transmit power and circuit power. To reveal the behavior of the optimized hybrid relay strategy, we analyze the optimal bit allocation for the hybrid relaying under different circuit power consumption and bidirectional data amounts. Analytical and simulation results show that, in a high-traffic region where the transmit power dominates the energy consumption, the hybrid relaying degenerates into two-way relaying. By contrast, in a low-traffic region where the circuit power consumption is dominant, the proposed hybrid relaying offers significant performance gain in the sense of EE over the pure one- and two-way relaying. © 1967-2012 IEEE.
Wu T.,Orange Group |
Wu T.,University Paris Est Creteil |
Wu T.,China Academy of Telecommunication Research |
Hadjem A.,Orange Group |
And 4 more authors.
Physics in Medicine and Biology | Year: 2010
This paper presents the whole-body specific absorption rate (WBSAR) assessment of embryos and new-born rats' exposure in a reverberating chamber (RC) operating at 2.4 GHz (WiFi). The finite difference in time domain (FDTD) method often used in bio-electromagnetism is facing very slow convergence. A new simulation-measurement hybrid approach has been proposed to characterize the incident power related to the RC and the WBSAR in rats, which are linked by the mean squared electric field strength in the working volume. Peak localized SAR in the rat under exposure is not included in the content of the study. Detailed parameters of this approach are determined by simulations. Evolutions for the physical and physiological parameters of the small rats at different ages are discussed. Simulations have been made to analyse all the variability factors contributing to the global results. WBSAR information and the variability for rats at different ages are also discussed in the paper. © 2010 Institute of Physics and Engineering in Medicine.
Liu R.,China Academy of Telecommunication Research |
Wu W.,China Academy of Telecommunication Research |
Yang D.,Post University
Advanced Materials Research | Year: 2012
Providing Machine-to-Machine (M2M) services is not only an opportunity but also a big challenge for telecom operators. Currently, the categorization of M2M services is mainly based on the serving field. Because the serving field is very large and new services will come up along with the progress of market, it is difficult for operators to provide services according to the serving field. Based on the real requirements from the operators and venders, there are 14 service features defined by 3GPP. However, the relation of different features is unclear. A new categorization method for M2M services based on the traffic characteristics is proposed in this paper. Based on the four traffic characteristics, including content type, data amount, transmission mode and priority of transferring, the M2M services are divided into five categories: mobile streaming, smart metering, regular monitoring, emergency alerting and mobile POS. Furthermore, the service characteristics and network requirements of each category are also analyzed. © (2012) Trans Tech Publications, Switzerland.
Li C.,University of Science and Technology Beijing |
Wu T.,China Academy of Telecommunication Research
IEEE International Symposium on Electromagnetic Compatibility | Year: 2014
This paper presents the dosimetric evaluation of the infant's exposure to electromagnetic fields from an electronic article surveillance system working at 125 kHz. A recently developed realistic infant anatomical model is deformed to achieve the standing, sitting and the supine postures. We perform the quasi-static calculation for the 99th percentile induced electric field, the peak specific absorption rate averaging over 10 g tissue and the maximum induced current density. A comparison has been made with the adult. The results show that the postures and the effective exposed part are very important factors for the dose results. The infant is not always overexposed compared with the adult. The magnetic field acquired by two methods can not be used for guidelines compliance evaluation. © 2014 The Institute of Electronics, Information and Communication Engineer.
Li S.,China Academy of Telecommunication Research
ICTIS 2013: Improving Multimodal Transportation Systems - Information, Safety, and Integration - Proceedings of the 2nd International Conference on Transportation Information and Safety | Year: 2013
A lot of researches ignore authenticity and integrity check of reported data from remote monitoring devices, which may result in security concerns. Considering potential attacks - such as data forgery and historical data replay - this paper puts forward a method to implement a customized encryption algorithm coupled with MCU IAP (In Application Programming) capability to enhance security, which can satisfy classified security requirements, and guarantee the data confidentiality, integrity, and freshness with rational cost. This framework makes the same device have wider application fields and comply with distinct criteria. For secret department, malicious data cheating may be dangerous if security check is ignored. © 2013 American Society of Civil Engineers.