Communication System Architecture Research Articles

Model-Based End-to-End Learning for WDM Systems With Transceiver Hardware Impairments

We propose an autoencoder (AE)-based transceiver for a wavelength division multiplexing (WDM) system impaired by hardware imperfections. We design our AE following the architecture of conventional communication systems. This enables to initialize the AE-based transceiver to have similar performance to its conventional counterpart prior to training and improves the training convergence rate. We first train the AE in a single-channel system, and show that it achieves performance improvements by putting energy outside the desired bandwidth, and therefore cannot be used for a WDM system. We then train the AE in a WDM setup. Simulation results show that the proposed AE significantly outperforms the conventional approach. More specifically, it increases the spectral efficiency of the considered system by reducing the guard band by 37% and 50% for a root-raised-cosine filter-based matched filter with 10% and 1% roll-off, respectively. An ablation study indicates that the performance gain can be ascribed to the optimization of the symbol mapper, the pulse-shaping filter, and the symbol demapper. Finally, we use reinforcement learning to learn the pulse-shaping filter assuming that the channel model is unknown. Simulation results show that the reinforcement-learning-based algorithm achieves similar performance as the standard supervised end-to-end learning approach assuming perfect channel knowledge.

Energy Efficient Data Transmission Scheme for Internet of Things Applications

Recently, there is a rapid increase in the use of Internet of Things (IoT) technology, and it is envisaged that in the forthcoming days, billions of devices and things are going to be interconnected among themselves with the help of Internet. To make this technology self-sustainable, there is a need for an incessant energy supply that can be achieved through green energy harvesting. IoT has attracted the attention of researchers as well as practitioners all over the globe by serving as an important architecture for communication systems, but the terminal devices used in IoT are resource-constrained, which results in low energy storage capacity and low computing power. Among several tasks that need to be performed at the level of IoT node, the data transmission is the most energy intensive phase. To provide continuous power to nodes used in IoT systems, it is imperative that the available energy source should be used judiciously and in an optimized manner. In this paper, an energy efficient data transmission scheme for IoT devices has been proposed. The result obtained through extensive experiments depicts that there is a high potential for saving energy during the process of data transmission.

Low-Complexity Chromatic Dispersion Equalization FIR Digital Filter for Coherent Receiver

This paper proposes a novel and efficient low-complexity chromatic dispersion equalizer (CDE) based on finite impulse response (FIR) filter architecture for polarization-multiplexed coherent optical communication systems. The FIR filter coefficients are optimized by weights to reduce the energy leakage caused by the truncation effect, and then quantization is used uniformly to reduce the number of real number additions and real number multiplications by utilizing the diversity of the quantized coefficients. Using Optisystem 15 to build a coherent optical communication system for simulation and experimental demonstration, the results show that after the filter coefficients are optimized by weights. Compared with the time-domain chromatic dispersion equalizer (TD-CDE), the proposed design has a lower bit error rate (BER) and better equalization effect. When the transmission distance is 4000 km and the system quantization stages M = 16, the multiplication operation and addition operations reduce computing resources by 99% and 43%, and the BER only increases by 5%. Compared with frequency-domain chromatic dispersion equalizer (FD-CDE), widely used in long-distance communication, the multiplication operation reduces computing resources by 30%. The proposed method provides a new idea for high-performance CDE in long-distance coherent optical communication systems.

The Indoor Space Layout of University Laboratories Based on Wireless Communication and Artificial Intelligence Decision-Making

In recent years, people have found that the use of contactless wireless communication can be more quickly interactive information transmission, which greatly facilitates our daily life. However, in the past, wireless communication is generally large-scale regional information dissemination. In recent years, with the further development of closed scenes, people are thinking about whether wireless communication can be used in closed scenes to do small and fast information transmission. The purpose of this paper is to study the indoor space layout of university laboratories based on wireless communication and artificial intelligence decision-making support. We are looking at the information about wireless communication to learn that wireless communication was often used in military transmission of signals and information; it has been vigorously developed and popularized, is now mainly used for civilian use, and can be combined with artificial intelligence to implement rapid information transmission transfer, in the data processing volume at a certain time basically achieving second transmission. Wireless communication and artificial intelligence decision-making can be used to conduct research on the indoor layout of college laboratories. In response, after data query and data comparison, we applied to the school for a computer lab and several idle laboratories to cooperate in experiments to facilitate the completion of the architecture of wireless communication and artificial intelligence systems, as well as subsequent data processing analysis. After a period of time of experiments, according to the results of the experiment, the use of wireless communication and artificial intelligence decision-making can help college laboratories according to their own functions, the installation of intelligent equipment, and the indoor layout of better arrangements.

Deep-BiGRU based channel estimation scheme for MIMO–FBMC systems

Deep Learning (DL)–based wireless communication systems have the potential to improve the conventional functions and current architecture of communication systems. In this paper, we propose a novel DL-based channel estimation scheme for multiple-input multiple-output filter bank multicarrier with offset quadrature amplitude modulation (MIMO-FBMC/OQAM) systems called deep bidirectional gated-recurrent unit (BiGRU) scheme. This scheme can easily be applied to a single-input single-output (SISO) system. The proposed scheme is divided into two stages: offline and online. The network is first trained in the offline stage. The prediction of channel information and estimation of the channel matrix using the trained network is then performed in the online stage. The simulation results in terms of the normalized mean square error (NMSE) and bit error rate (BER) demonstrate that, under different time-varying channel models, the proposed DL scheme significantly improves the channel estimation performance of FBMC for single and multiple antennas compared to conventional interference approximation method (IAM) channel estimation methods.

Dual-Band Direct Conversion Receiver With Additive Mixing Architecture

A dual-band direct conversion receiver based on additive mixing architecture for low-cost and multi-mode wireless communication systems is proposed. The proposed receiver consists of two active four-port junctions for additive mixing and one-stage dual-band polyphase filter for quadrature LO signal generation. Each four-port junction is fabricated with <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18~\mu \text{m}$ </tex-math></inline-formula> CMOS technology and configured by an active balun, two buffer amplifiers, two active combiners and two power detectors. The proposed polyphase filter is implemented using type-I architecture adopting one-stage and R-LC resonance type for low power and dual-band operation. The phase and amplitude calibration schemes are also integrated to effectively correct I/Q mismatch within the proposed architecture. The calibration ranges for the phase and amplitude mismatches show 8° and 14 dB, respectively. The validity of the proposed receiver based on additive mixing method is successfully demonstrated by demodulating 16-QAM signals with 40 Mbps at the dual band of 900 MHz and 2.4 GHz.

Versatile and Concurrent FPGA-Based Architecture for Practical Quantum Communication Systems

This article presents a hardware and software architecture, which can be used in those systems that implement practical quantum key distribution (QKD) and quantum random-number generation (QRNG) schemes. This architecture fully exploits the capability of a System on a Chip (SoC), which comprehends both a field-programmable gate array (FPGA) and a dual-core CPU unit. By assigning the time-related tasks to the FPGA and the management to the CPU, we built a flexible system with optimized resource sharing on a commercial off-the-shelf (COTS) evaluation board, which includes an SoC. Furthermore, by changing the dataflow direction, the versatile system architecture can be exploited as a QKD transmitter, QKD receiver, and QRNG control-acquiring unit. Finally, we exploited the dual-core functionality and realized a concurrent stream device to implement a practical QKD transmitter, where one core continuously receives fresh data at a sustained rate from an external QRNG source, while the other operates with the FPGA to drive the qubit transmission to the QKD receiver. The system was successfully tested on a long-term run proving its stability and security. This demonstration paves the way toward a more secure QKD implementation, with fully unconditional security as the QKD states are entirely generated by a true random process and not by deterministic expansion algorithms. Eventually, this enables the realization of a standalone quantum transmitter, including both the random numbers and the qubit generation.

Cognitive Communications System for Ultra-Low Size, Weight and Power (SWAP) Attributable Platforms

Communications resiliency and data distribution assurance has been compromised in highly competitive, dynamic, and stressing environments with the introduction of off the shelf, high performing jammers. This paper introduces a novel cognitive communications system that can be fielded on small attributable platforms; the architecture amalgamates a highly capable environmentally perceptive aperture, a software defined radio, and sophisticated networking techniques. The proposed cognitive communications system uses the 5G new radio waveform and applies groundbreaking machine learning methods to facilitate systems orchestration amongst its subsystems to transfer information effectively between nodes, and across large-scale multi-hop networks, essential for rapid strike missions. With the challenges imposed by mature and readily available jammers, a cognitive communications system can be used to maintain and sustain continuous communications to provide near real-time surveillance and situational awareness updates. In addition to describing the comprehensive cognitive communications system architecture, a jamming analysis will be presented. Performance results for an operational use case will be compared to existing trite architectures consisting of siloed apertures and standard radio systems to demonstrate an improvement of approximately 10 dB in communications margin with the auspicious technology offering of the cognitive communications system for low size, weight, and power attributable platforms.

Synthesis of information and telecommunication networks of automatized environmental security systems with the purpose of gaining maximum noise resistance with a given efficiency

The article defines the system features, properties and characteristics of information and telecommunication networks of automated environmental safety systems: information reliability and proven efficiency as a fundamental characteristic of system perfection. The main task of this research is to standardize the highest level of information and telecommunications networks architecture that provide the creation, processing, storage, deletion and transportation of information. In this case, the architecture is considered as a single for: all types of networks (including network services): optical transport network, Internet network (data network), fixed telephone network, mobile network and all types of products, customers, services, resources, aspects of management. A very important requirement is that the system architecture should not change when changing the structure of products, market requirements or the structure of the company. Standardization of information systems architecture involves: defining a complete list of architecture components; determination of functional boundaries of components; definition of interfaces (protocols) of interaction of components. The main purpose of architecture standardization is: to reduce the implementation of telecommunications services by reducing the time for implementation and modernization of information systems, and increase the efficiency of implementation of information systems, as well as reduce costs for their creation and operation by: avoiding duplication of functions; use of open interfaces; repeated use of the same type of elements. The research concerns the structural synthesis of the architectures of four main telecommunication networks: transport, IP, mobile and fixed. Eight sets of network resources (levels) were selected to standardize each network architecture. Based on the results of the analysis, it is possible to draw a conclusion about the development potential of each network depending on the trends of modern telecommunications services. The telecommunication services means of production architecture, which include platforms of network resources and network services, is considered. The article proposes a methodological basis for the synthesis of information and communication technology systems in order to establish a single information platform, which is presented as a universal architecture of information and communication systems. The messaging service is considered in the context of: one workstation, one domain and interconnection between domains. The efficiency of information transmission systems is considered. When evaluating different communication systems, two indicators were taken into account: efficiency and noise immunity; their combination gives a fairly complete description of the system. The most perfect system is the one that provides the greatest efficiency at a given noise immunity or, conversely, the greatest noise immunity at a given efficiency.

Path Loss and Channel Modeling at 3.5GHz for 5G Cellular System

Wireless channel characterization is the basis of the architecture of the wireless communication system. The detailed propagation models are indeed the requirement for fifth generation communication network design. This paper presents the characteristics of channel propagation for a fifth-generation system in Line-of-Sight (LOS) and Non-Line-of-Sight (NLOS) scenarios with co-polarization (V-V) and cross polarization (V-H) in a second floor/Communication Engineering Department/Electronics college building at 3.5GHz frequency. The comparison between two path loss models shows that the Close-In (CI) of free space reference distance path loss model is more suitable than Floating-Intercept (FI) path loss model. The results of both models show that the path loss exponent value (n) is ranged between 1.7 and 2.9 for the LOS scenario, while it was between 2.1 and 3.1 for NLOS scenario for both co-polarization and cross polarization.

Dynamic networking and channel access strategies of hybrid communication network for intelligent ship

Based on the architecture of the hybrid maritime communication system, the shipboard hybrid communication network structure is presented for multi-network and multi-mode transmission networking equipment of intelligent ship. The paper briefly introduces the proposed dynamic networking and channel access strategies for the communication system of ship-to-ship and ship-to-shore, as well as the communication data types and priorities, quantitative description for each data and performance of each link. Those strategies make the shipboard communication link will be established automatically and flexibly with many modern communication technologies which will be selected depending on the current conditions of the radio channel and the requirements and preferences of the user. Simulation experiments show that those strategies could achieve the flexible and efficient data transmission with high throughput and low delay, using the advantage of each communication technology.

5G Visible Light Communication - OCDMA Setup using Catenated-OFDM Modulation Method

This paper demonstrates a new high-speed architecture of visible light communication (VLC) system combining with zero cross correlation (ZCC) code of optical code division multiplexing (OCDMA) and novel catenated-OFDM modulation scheme. In order to achieved high spectral efficiency and higher bit rate system for 5G application, we embedded multiband catenated-OFDM modulation technique and OCDMA in VLC design system. Moreover, by employing visible laser diode (VLD) in designing VLC system, we achieved 10 Gbps bit rate at 2.5 dBm input power. We investigate this new combination system design to analyze the bit rate and bit error rate (BER) in 3 m indoor VLC channel propagation.

An Overview of LoRaWAN

LoRa is an IoT enabling technology which is particularly suitable for low data rate applications. The technology can achieve extended network coverage while operating in unlicensed ISM band and falls into the category of Low­Power­Wide­Area­Networks (LPWANs) technologies. Among the non­cellular based LPWAN enabling technologies, LoRa has got remarkable attention due to its fast adoption by industries. LoRa through wireless modulation enables the end­nodes to establish long distance communication while LoRaWAN refers to the communication protocol and system architecture. In this paper, an overview of LoRaWAN is presented.

A Trust Based Scheme to Protect 5G UAV Communication Networks

With the increasing demands of social services, Unmanned Aerial Vehicles (UAVs)-assisted networks promote promising prospect for improving social services. The sensing data can be collected by UAVs, a large number of applications based on UAVs can be realized in 5G networks. However, the malicious UAVs may provide false information and destroy services. The 5G UAV communication systems face the security threats. Therefore, this paper develops a novel trust-based security scheme for 5G UAV communication systems. The architecture of 5G UAV communication system is first presented to improve the communication performance. Second, a trust evaluation scheme for UAVs is developed to evaluate the reliability of UAVs. By introducing the trust threshold, the malicious UAVs will be filtered out from the systems. Third, with the assistance of mobile edge computing (MEC) nodes, the detection scheme based on Q-learning technology is proposed to detect the malicious attacks. The security threats can be detected to protect the security of systems. Finally, simulation results demonstrate the effectiveness of the proposed scheme.

Artificial Intelligence for Radio Communication Context-Awareness

This paper surveys Artificial Intelligence (AI) methods for acquiring and managing context-of-operation awareness of radio communication nodes, links, and networks. The meaning and significance of context information and suitability of Machine Learning (ML) methods for the enrichment of context information is discussed. A number of context features are considered in this regard and thorough analysis on which ML methods are suitable to which part of context learning is provided. The added value of the paper is the presentation of a synthesized framework of context-information processing, sharing, and management in a radio communication network by delineating a network-embedded subsystem for this management. Recommendations for a future AI/ML-based radio communication system architectures are also provided.

Introduction to global short message communication service of BeiDou-3 navigation satellite system

Short Message Communication (SMC) is a featured service of BeiDou Navigation Satellite System (BDS). After its successful deployment in 2003, Regional Short Message Communication (RSMC) service has been continuously serving China and its neighboring countries and regions, especially in life safety scenarios. In this paper, the architecture of the Global Short Message Communication (GSMC) system is proposed based on the medium earth orbit (MEO) constellation and the crosslinks of the global BeiDou navigation system (BDS-3). Three subtypes of GSMC service, i.e. positioning report, emergency search and rescue (SAR) and regular SMC are designed in accordance with the technical characteristic of integration of navigation and communication in BDS-3, which supports future wide applications of GSMC. The performance of the designed GSMC system is analyzed by numerical calculations. As BDS-3 was officially announced completion on July 31, 2020, GSMC has been providing initial service. First test results of the in orbit GSMC payloads are also presented in the paper to verify the designed capabilities. Preliminary results also show that the requirements of Global Maritime Distress and Safety System (GMDSS) can also be fulfilled.

A Dual-Functional Massive MIMO OFDM Communication and Radar Transmitter Architecture

In this study, a dual-functional radar and communication (RadCom) system architecture is proposed for application at base-stations (BSs), or access points (APs), for simultaneously communicating with multiple user equipments (UEs) and sensing the environment. Specifically, massive multiple-input multiple-output (mMIMO) communication and orthogonal frequency-division multiplexing (OFDM)-based MIMO radar are considered with the objective to jointly utilize channel diversity and interference. The BS consists of a mMIMO antenna array, and radar transmit and receive antennas. Employing OFDM waveforms for the radar allows the BS to perform channel state information (CSI) estimation for the mMIMO and radar antennas simultaneously. The acquired CSI is then exploited to predict the radar signals received by the UEs. While the radar transmits an OFDM waveform for detecting possible targets in range, the communication system beamforms to the UEs by taking into account the predicted radar interference. To further enhance the capacity of the communication system, an optimum radar waveform is designed. Moreover, the network capacity is mathematically analyzed and verified by simulations. The results show that the proposed RadCom can achieve higher capacity than conventional mMIMO systems by utilizing the radar interference while simultaneously detecting targets.

5G network-oriented hierarchical distributed cloud computing system resource optimization scheduling and allocation

As the core technology of the next generation mobile communication system, the development of 5G key technologies needs to be able to efficiently and effectively support massive data services. Aiming at the impact of massive data traffic on mobile communication networks in 5G communication systems, this paper proposes a 5G-oriented hierarchical distributed cloud service mobile communication system architecture. The model consists of a cloud access layer, a distributed micro-cloud system, and a core cloud data center. The distributed micro cloud system consists of multiple micro clouds that are deployed to the edge of the network. The service content in the core cloud data center can be deployed and cached to the local micro cloud server in advance to reduce repeated redundant transmission of user requested content in the network. Aiming at the problem of how to determine the migration object when dynamically optimizing the resource structure, a heuristic function-based dynamic optimization algorithm for cloud resources is proposed. The experimental results show that the dynamic expansion algorithm of cloud resources based on dynamic programming ideas can better improve the performance of virtual resources, and the dynamic optimization algorithm of cloud resources based on heuristic functions can effectively and quickly optimize the resource structure, thereby improving the operating efficiency of user virtual machine groups. An efficient resource allocation scheme based on cooperative Q (Quality) learning is proposed. The environmental knowledge obtained by the base station learning and exchanging information is used for distributed resource block allocation. This resource allocation scheme can obtain the optimal resource allocation strategy in a short learning time, and can terminate the learning process at any time according to the delay requirements of different services. Compared with traditional resource allocation schemes, it can effectively improve system throughput.

Satellite Communication System adopts OFDM-MIMO Technology with High Speed Connectivity

The space communication development has strong urgent requirement for technology upgrading and evolution. The satellite communication capacity can be advanced by the application of higher data transmission efficiency. It will be contented with diversified High Throughput Satellite (HTS) communication application requirements. A satellite communication system architecture design featured by higher transmission efficiency using Multi-Input & Multi-Output (MIMO) and Orthogonal Frequency Division Multiplexing (OFDM) technology which has been wildly used in next generation of terrestrial wireless communications has been presented. It is proposed to solving problems on multiplexing data transmission, receiving signal’s anti-interference, and supporting various multi-user terminals. The throughput and application analysis was done to evaluate system performance in terms of diverse HTSs. A comprehensive evaluation and simulation analysis of space communication application efficiency are carried out to verify the feasibility of basic space application under the diverse simulation conditions. The total throughput of the communication system can reach up to 259Gbps as extremely high speed connectivity, and the maximum spectrum efficiency is close to the ultimate performance of 100bits/s/Hz.

Performance of Distributed Massive MIMO and Small-Cell Systems Under Hardware and Channel Impairments

Deploying a large number of distributed access points (AP)s to serve a smaller number of users is one of the promising network architectures for future wireless communication systems. Such network architecture can be operated as a distributed massive multiple-input multiple-output (MIMO) system or as a small-cell (SC) system to satisfy the anticipated high rate requirements for beyond-5G networks. However, in a practical scenario with non-ideal hardware components and high-velocity users, the network experiences an inevitable performance degradation. This paper aims at analyzing the network performance under the operation of distributed massive MIMO and SC systems, taking into account the impairments of real and dynamic systems. Considering multiple-antennas APs, we derive novel closed-form expressions for the downlink (DL) spectral efficiency of both systems. We reveal that limiting the number of served users per AP in distributed massive MIMO systems leads to a corresponding loss in the performance, especially under max-min power control. Besides, despite the SC system provides the largest per-user average DL rate under the deployment of ideal APs, distributed massive MIMO systems become superior in the presence of non-ideal APs. Notably, while increasing the number of deployed non-ideal APs can reduce the introduced loss in distributed massive MIMO systems, this leads to an extra performance loss in SC systems. Finally, we show that the presence of high-velocity users is more harsh in SC systems. In addition, our results show that the SC system operation is more suitable for low-velocity users, however, it is better to operate networks with high velocities users under the distributed massive MIMO systems operation.