A Learning-Based Channel Model for Synergetic Transmission Technology

It is extensively approved that Channel State Information(CSI) plays an important role for synergetic transmission and interference management. However, pilot overhead to obtain CSI with enough precision is a significant issue for wireless communication networks with massive antennas and ultra-dense cell. This paper proposes a learning- based channel model, which can estimate, refine, and manage CSI for a synergetic transmission system. It decomposes the channel impulse response into multiple paths, and uses a learning-based algorithm to estimate paths' parameters without notable degradation caused by sparse pilots. Both indoor measurement and outdoor measurement are conducted to verify the feasibility of the proposed channel model preliminarily.

Cybersecurity Landscape on Remote State Estimation:A Comprehensive Review

Cyber-physical systems(CPSs)have emerged as an essential area of research in the last decade,providing a new paradigm for the integration of computational and physical units in modern control systems.Remote state estimation(RSE)is an indispensable functional module of CPSs.Recently,it has been demonstrated that malicious agents can manipulate data packets transmitted through unreliable channels of RSE,leading to severe estimation performance degradation.This paper aims to present an overview of recent advances in cyber-attacks and defensive countermeasures,with a specific focus on integrity attacks against RSE.Firstly,two representative frameworks for the synthesis of optimal deception attacks with various performance metrics and stealthiness constraints are discussed,which provide a deeper insight into the vulnerabilities of RSE.Secondly,a detailed review of typical attack detection and resilient estimation algorithms is included,illustrating the latest defensive measures safeguarding RSE from adversaries.Thirdly,some prevalent attacks impairing the confidentiality and data availability of RSE are examined from both attackers'and defenders'perspectives.Finally,several challenges and open problems are presented to inspire further exploration and future research in this field.

AN IMPROVED EPON UPSTREAM TRANSMISSION SCHEME WITH ZERO INTER-PERIOD IDLE LOSS

Existing Ethernet Passive Optical Network(EPON) Dynamic Bandwidth Allocation(DBA) algorithms suffer from the disadvantage of idle time loss,which lower the upstream bandwidth utili-zation.This letter proposes an improved upstream transmission scheme with idle-time eliminating mechanism.Theoretical analysis and numerical calculation prove that the improved scheme can ef-fectively eliminate the idle time and enhance the efficiency of upstream link utilization.Simulation results have shown that the bandwidth utilization can be raised up to 15% in heavy-load scenarios while the time delay performance of Assured Forwarding(AF) and Best Effort(BE) services are improved simultaneously.

Simple and practical method of characterizing the parametric down-conversion source

Parametric down-conversion（PDC） sources play an important role in quantum information processing, therefore characterizing their properties is necessary. Here we present a statistical model to assess the properties of the PDC source with certain distribution, such as the brightness and photon channel transmissions, we only need to measure the singles and coincidences counts in a few seconds. Furthermore, we validate the model by applying it to a PDC source generating highly non-degenerate photon pairs. The results of the experiment indicate that our method is more simple, efficient, and less time consuming.

RF characteristics of wireless capsule endoscopy in human body

The wireless capsule endoscope,as a small electronic device,has conquered some limitations of traditional wired diagnosing tools,such as the uncomfortableness of the cables for the patient and the inability to examine the very convoluted small intestine section.However,this technique is still encountering a lot of practical challenges and is looking for feasible improvements.This work investigates the RF performance of the wireless capsule endoscope system by studying the electromagnetic(EM) wave propagation within the human body.A wireless capsule endoscopy transmission channel model is constructed to serve the purpose of investigating signal attenuations according to the relative position between the transmitter and the receiver.Within 300-500 MHz,the S_(21) results are regular and do not display any sudden changes,which allows a suitable expression to be derived for S_(21) in terms of frequency and offset.The results provide useful information for capsule localization.

Secure Transmission Scheme for Parallel Relay Channels Based on Polar Coding

This paper considers the use of polar codes to enable secure transmission over parallel relay channels.By exploiting the properties of polar codes over parallel channels, a polar encoding algorithm is designed based on Channel State Information（CSI） between the legitimate transmitter（Alice） and the legitimate receiver（Bob）.Different from existing secure transmission schemes, the proposed scheme does not require CSI between Alice and the eavesdropper（Eve）. The proposed scheme is proven to be reliable and shown to be capable of transmitting information securely under Amplify-and-Forward（AF） relay protocol, thereby providing security against passive and active attackers.

A self-adaptive full asynchronous bi-directional transmission channel for network-on-chips

To improve two shortcomings of conventional network-on-chips,i.e.low utilization rate in channels between routers and excessive interconnection lines,this paper proposes a full asynchronous self-adaptive bi-directional transmission channel.It can utilize interconnection lines and register resources with high efficiency,and dynamically detect the data transmission state between routers through a direction regulator,which controls the sequencer to automatically adjust the transmission direction of the bi-directional channel,so as to provide a flexible data transmission environment.Null convention logic units are used to make the circuit quasi-delay insensitive and highly robust. The proposed bi-directional transmission channel is implemented based on SMIC 0.18μm standard CMOS technology. Post-layout simulation results demonstrate that this self-adaptive bi-directional channel has better performance on throughput,transmission flexibility and channel bandwidth utilization compared to a conventional single direction channel.Moreover,the proposed channel can save interconnection lines up to 30%and can provide twice the bandwidth resources of a single direction transmission channel.The proposed channel can apply to an on-chip network which has limited resources of registers and interconnection lines.

Application Research on Space Laser Communication in Bistatic Radar System

There exist three synchronizing problems in the bistatic radar system that some signals of the radar receiver must be synchronized with those of the radar transmitter. Several methods realizing data transmission, which are used to complete the synchronization existing in the bistatic radar system, are described. Then a new idea is brought forward that employs space laser communication in the bistatic radar system to realize its data transmission. The theoretic analysis of the idea's usability and its merits are discussed in details. Finally the latest development of space laser communication is introduced, and the utility of the idea is pointed out further.

43 Gbit/s x 54 ch Transmission with Dense 75 GHz Channel Spacing in NRZ Modulation Scheme

We demonstrated 2.16-Tbit/s (43 Gbit/s x 54 ch) WDM transmission over 600 km of standard single-mode fiber with high spectral efficiency 0.53 bit/s/Hz using optimized optical mux/demux filters for 75-GHz channel spacing in a simple NRZ modulation scheme.

Stable error-free single channel 160-Gb/s OTDM 100-km transmission via high-precision dispersion management

A single channel with a 160-Gb/s optical time-division-multiplexing （OTDM） transmission over 100 km is fabricated. With the help of 500-GHz optical sampling oscilloscopes, the fiber length is adjusted to the order of 10 m, which corresponds to the accuracy of 0.4 ps for the dispersion compensation. The dispersion map is optimized for the 100-km transmission link. A completely error-free transmission with the power penalty of 3.6 dB is achieved for 2 h without using forward error correction.

Transmission of 2.5 Gb/s WDM Channels Spaced at 5 GHz over 480 km of Single-Mode Fiber

We demonstrate the transmission of 2.5-Gb/s WDM signals spaced at 5 GHz over 480 km of single-mode fiber. The results indicate that it should be possible to transmit more than one thousand 2.5-Gb/s channels spaced at 5 GHz over long distance.

Estimating Digital Inter-Symbol Interference Channel Blindly Based on the One-Step Branch Transition Rules in Trellises

A novel discrete-time digital inter-symbol interference (ISI) channel blind estimation sub-optimal algorithm is proposed. This algorithm reduces the complexity of the optimal maximum likelihood sequence estimation (MLSE) considerably based on the one-step branch transition rules in trellises, and is suitable for the estimation of the channels with small lengths of ISI.

Self-error-rejecting photonic qubit transmission in polarization-spatial modes with linear optical elements

We present an original self-error-rejecting photonic qubit transmission scheme for both the polarization and spatial states of photon systems transmitted over collective noise channels. In our scheme, we use simple linear-optical elements, including half-wave plates, 50:50 beam splitters, and polarization beam splitters, to convert spatial-polarization modes into different time bins. By using postselection in different time bins, the success probability of obtaining the uncorrupted states approaches 1/4 for singlephoton transmission, which is not influenced by the coefficients of noisy channels. Our self-error-rejecting transmission scheme can be generalized to hyperentangled n-photon systems and is useful in practical high-capacity quantum communications with photon systems in two degrees of freedom.

Consumption Inequality in China： Theory and Evidence from the China Health and Nutrition Survey

We investigate consumption inequality in China both theoretically by constructing a theoretical model that delineates the transmission channels by which income shocks affect consumption and empirically through an Unequally Spaced Dynamic Panel Data model estimation. We find that China is experiencing consumption inequality with the full partial insurance of consumption against both permanent and transitory income shocks, although the impact of both types of shock are larger than the case of the United States. The results are due to precautionary savings motives of the Chinese. We further document how income becomes more dispersed in China and show how the family background of a child affects his outcome to a large extent. Policy implications based on our findings are proposed.