Ericsson (Canada)

In this paper, we present space shift keying (SSK) as a new modulation scheme, which is based on spatial modulation (SM) concepts. Fading is exploited for multiple-input multiple-output(MIMO) channels to provide better performance over conventional amplitude/phase modulation (APM) techniques. In SSK, it is the antenna index used during transmission that relays information, rather than the transmitted symbols themselves. This absence of symbol information eliminates the transceiver elements necessary for APM transmission and detection (such as coherent detectors). As well, the simplicity involved in modulation reduces the detection complexity compared to that of SM, while achieving almost identical performance gains. Throughout the paper, we illustrate SSK's strength by studying its interaction with the fading channel. We obtain tight upper bounds on bit error probability, and discuss SSK's performance under some non-ideal channel conditions (estimation error and spatial correlation). Analytical and simulation results show performance gains over APM systems (3 dB at a bit error rate of 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">-5</sup> ), making SSK an interesting candidate for future wireless applications. We then extend SSK concepts to incorporate channel coding, where in particular, we consider a bit interleaved coded modulation (BICM) system using iterative decoding for both convolutional and turbo codes. Capacity results are derived, and improvements over APM are illustrated (up to 1 bits/s/Hz), with performance gains of up to 5 dB.

Over the last few years, we have experienced a variety of access technologies being deployed. While 2G cellular systems evolve into 3G systems such as UMTS or cdma2000, providing worldwide coverage, wireless LAN solutions have been extensively deployed to provide hotspot high-bandwidth Internet access in airports, hotels, and conference centers. At the same time, fixed access such as DSL and cable modem tied to wireless LANs appear in home and office environments. The always best connected (ABC) concept allows a person connectivity to applications using the devices and access technologies that best suit his or her needs, thereby combining the features of access technologies such as DSL, Bluetooth, and WLAN with cellular systems to provide an enhanced user experience for 2.5G, 3G, and beyond. An always best connected scenario, where a person is allowed to choose the best available access networks and devices at any point in time, generates great complexity and a number of requirements, not only for the technical solutions, but also in terms of business relationships between operators and service providers, and in subscription handling. This article describes the concept of being always best connected, discusses the user experience and business relationships in an ABC environment, and outlines the different aspects of an ABC solution that will broaden the technology and business base of 3G.

Densification of network base stations is indispensable to achieve the stringent Quality of Service (QoS) requirements of future mobile networks. However, with a dense deployment of transmitters, interference management becomes an arduous task. To solve this issue, exploring radically new network architectures with intelligent coordination and cooperation capabilities is crucial. This survey paper investigates the emerging user-centric cell-free massive Multiple-input multiple-output (MIMO) network architecture that sets a foundation for future mobile networks. Such networks use a dense deployment of distributed units (DUs) to serve users; the crucial difference from the traditional cellular paradigm is that a specific serving cluster of DUs is defined for each user. This framework provides macro diversity, power efficiency, interference management, and robust connectivity. Most importantly, the user-centric approach eliminates cell edges, thus contributing to uniform coverage and performance for users across the network area. We present here a guide to the key challenges facing the deployment of this network scheme and contemplate the solutions being proposed for the main bottlenecks facing cell-free communications. Specifically, we survey the literature targeting the fronthaul, then we scan the details of the channel estimation required, resource allocation, delay, and scalability issues. Furthermore, we highlight some technologies that can provide a management platform for this scheme such as distributed software-defined network (SDN). Our article serves as a check point that delineates the current status and indicates future directions for this area in a comprehensive manner.

The ambitious high data-rate applications in the envisioned future beyond fifth-generation (B5G) wireless networks require new solutions, including the advent of more advanced architectures than the ones already used in 5G networks, and the coalition of different communications schemes and technologies to enable these applications requirements. Among the candidate communications schemes for future wireless networks are non-orthogonal multiple access (NOMA) schemes that allow serving more than one user in the same resource block by multiplexing users in other domains than frequency or time. In this way, NOMA schemes tend to offer several advantages over orthogonal multiple access (OMA) schemes such as improved user fairness and spectral efficiency, higher cell-edge throughput, massive connectivity support, and low transmission latency. With these merits, NOMA-enabled transmission schemes are being increasingly looked at as promising multiple access schemes for future wireless networks. When the power domain is used to multiplex the users, it is referred to as the power domain NOMA (PD-NOMA). In this paper, we survey the integration of PD-NOMA with the enabling communications schemes and technologies that are expected to meet the various requirements of B5G networks. In particular, this paper surveys the different rate optimization scenarios studied in the literature when PD-NOMA is combined with one or more of the candidate schemes and technologies for B5G networks including multiple-input-single-output (MISO), multiple-input-multiple-output (MIMO), massive-MIMO (mMIMO), advanced antenna architectures, higher frequency millimeter-wave (mmWave) and terahertz (THz) communications, advanced coordinated multi-point (CoMP) transmission and reception schemes, cooperative communications, cognitive radio (CR), visible light communications (VLC), unmanned aerial vehicle (UAV) assisted communications and others. The considered system models, the optimization methods utilized to maximize the achievable rates, and the main lessons learnt on the optimization and the performance of these NOMA-enabled schemes and technologies are discussed in detail along with the future research directions for these combined schemes. Moreover, the role of machine learning in optimizing these NOMA-enabled technologies is addressed.

As the specification of Release 11 of the LTE standards is approaching its completion, 3GPP is gradually moving its focus toward the next major step in the evolution of LTE. The drivers of the LTE evolution include the increasing demand for mobile broadband services and traffic volumes as well as emerging usage scenarios involving short-range and machine-type communications. In this article we provide an overview of the key technology areas/components that are currently considered by 3GPP for Rel-12, including support for further enhanced local area access by tight interaction between the wide area and local area layers, signaling solutions for wireless local area network integration, multi-antenna enhancements, improved support for massive MTC, and direct device-to-device communications.

The development of cloud computing services is speeding up the rate in which the organizations outsource their computational services or sell their idle computational resources. Even though migrating to the cloud remains a tempting trend from a financial perspective, there are several other aspects that must be taken into account by companies before they decide to do so. One of the most important aspect refers to security: while some cloud computing security issues are inherited from the solutions adopted to create such services, many new security questions that are particular to these solutions also arise, including those related to how the services are organized and which kind of service/data can be placed in the cloud. Aiming to give a better understanding of this complex scenario, in this article we identify and classify the main security concerns and solutions in cloud computing, and propose a taxonomy of security in cloud computing, giving an overview of the current status of security in this emerging technology.

Vehicle-to-everything (V2X) communication and services have been garnering significant interest from different stakeholders as part of future intelligent transportation systems (ITSs). This is due to the many benefits they offer. However, many of these services have stringent performance requirements, particularly in terms of the delay/latency. Multi-access/mobile edge computing (MEC) has been proposed as a potential solution for such services by bringing them closer to vehicles. Yet, this introduces a new set of challenges such as where to place these V2X services, especially given the limit computation resources available at edge nodes. To that end, this work formulates the problem of optimal V2X service placement (OVSP) in a hybrid core/edge environment as a binary integer linear programming problem. To the best of our knowledge, no previous work considered the V2X service placement problem while taking into consideration the computational resource availability at the nodes. Moreover, a low-complexity greedy-based heuristic algorithm named “Greedy V2X Service Placement Algorithm” (G-VSPA) was developed to solve this problem. Simulation results show that the OVSP model successfully guarantees and maintains the QoS requirements of all the different V2X services. Additionally, it is observed that the proposed G-VSPA algorithm achieves close to optimal performance while having lower complexity.

While the technology development towards microservices can significantly improve the speed and agility of software service delivery, it also raises the operational complexity associated with modern applications. This has led to the emergence of Service Mesh, a promising approach to mitigate this situation by introducing a dedicated infrastructure layer over microservices without imposing modification on the service implementations. Aiming to inspire more practical research work in this exploited area, we in this paper present a comprehensive review on the state of the art of Service Mesh and discuss the related challenges and its adoption. Finally, we highlight the opportunities for future research in this subject.

E-commerce has become a huge business and a driving factor in the development of the Internet. Online shopping services are well established and will, with the advent of evolved 2G and 3G mobile networks, soon be complemented by their wireless counterparts. Furthermore, online delivery of digital media, such as MP3 audio or video, is very popular today and will become an increasingly important part of e-commerce and mobile e-commerce (m-commerce). However, a major obstacle for digital media distribution and associated business is the possibility of unlimited consecutive copying in the digital domain, which threatens intellectual property rights (e.g., copyrights). Digital rights management systems are required to protect rights and business. DRM systems typically incorporate encryption, conditional access, copy control mechanisms, and media identification and tracing mechanisms. Watermarking is the technology used for copy control and media identification and tracing. Most proposed watermarking methods use a so-called spread spectrum approach: a pseudo-noise signal with small amplitude is added to the host signal, and later on detected using correlation methods. A secret key is used to ensure that the watermark can only be detected and removed by authorized parties. Thus, watermarking is an essential component of modern DRM systems. Several standardization bodies are involved in DRM standardization. Some examples, (MPEG-4, SDMI, and DVD), are discussed in this article. Watermarking as an enabling technology is especially highlighted. Furthermore, the relation between DRM and m-commerce, and the impact on business models for m-commerce are discussed. A common experience today is that Internet e-commerce applications cannot always easily be adapted for mobile telecommunications systems. We emphasize, however, that DRM and watermarking can benefit from the additional information available in mobile telecommunications systems, and can thus help to improve rights management for digital media delivery.

Network slicing is a key paradigm in 5G and is expected to be inherited in future 6G networks for the concurrent provisioning of diverse quality of service (QoS). Unfortunately, effective slicing of Radio Access Networks (RAN) is still challenging due to time-varying network situations. This paper proposes a new intelligent RAN slicing strategy with two-layered control granularity, which aims at maximizing both the long-term QoS of services and spectrum efficiency (SE) of slices. The proposed method consists of an upper-level controller to ensure the QoS performance, which enforces loose control by performing adaptive slice configuration according to the long-term dynamics of service traffic. The lower-level controller is to improve SE of slices, by tightly scheduling radio resources to users at the small time-scale. To realize the proposed RAN slicing strategy, we propose a model-free deep reinforcement learning (DRL) framework, which is a hierarchical structure that collaboratively integrating the modified deep deterministic policy gradient (DDPG) and double deep-Q-network algorithm. Specifically, the lower-level control problem is a mixed-integer stochastic optimization problem with multiple constraints. This kind of problem is hard to be directly solved by the exiting DRL algorithms, since it involves searching for the solution in a vast set of mixed-integer action space, which will induce unbearable computational complexity. Thus, we propose a novel action space reducing approach, embedding the convex optimization tools into the DDPG algorithm, to speed up the lower-level control. Furthermore, simulation results confirm the effectiveness of our proposed intelligent RAN slicing scheme.

. In addition, we perform a detailed experimental parametric study of the coherent-lite system in which various system parameters are swept such as baud rate, reach, laser power and laser linewidth. Our results verify that the coherent-lite system can be realized using low-cost DFB lasers with linewidths of a few hundred kHz. Moreover, we compare the performance of the coherent-lite system with that of a conventional coherent transceiver leveraging the full DSP stack. Then, we evaluate the power consumption savings achieved by the coherent-lite scheme relative to a classic DSP-based coherent system. Assuming a CMOS node ranging from 28 to 7 nm for DSP implementation, our estimate shows that the coherent-lite scheme can save 95 to 78% of the power consumed by the following subsystems: analog-to-digital converters, chromatic dispersion compensation, 2 × 2 MIMO polarization demultiplexing and carrier recovery. Finally, we compare the power consumption of the coherent-lite scheme with more standard 400G IM-DD systems utilizing either eight or four parallel WDM lanes (8 × 50G and 4 × 100G). The coherent-lite system is found to have similar module power consumption requirements as a corresponding 4 × 100G IM-DD system while bringing the benefits of coherent detection including improved sensitivity and higher spectral efficiency leading to fewer light sources per transceiver module. To the best of our knowledge, this work represents the first experimental demonstration of a DSP-free coherent-lite system for single channel 400G datacenter 10 km interconnects, a potential attractive solution due to its scalability to future 800G and 1.6T intra-datacenter optical interconnects.

In 1997 the Defense Advanced Research Projects Agency initiated a program to explore the possibility of micro air vehicles for the purpose of individually portable surveillance systems for close-range operations. The various contractors approached the problem in several ways, such as developing tiny fixed-wing airplanes, rotary-wing aircraft, and ornithopters mimicking animal flight This paper describes one such flapping-wing aircraft, which drew upon the clap-fling phenomenon that is exploited by many flying animals and insects for lift generation. Essentially this aircraft was a mechanical simulation of hummingbird flight, though with two sets of wings to eliminate the unbalanced side-to-side flapping forces. Two flying demonstration models were built, one with an internal-combustion engine and another with an electric motor. In both cases, these incorporated a drive train to reduce the high rpm rotary shaft motion to lower-frequency oscillation for flapping. Also required was a programmable logic board for stabilization. Successful hovering flight was achieved with both models, and initial studies of transition to horizontal flight were also explored.

We present a Silicon Photonic (SiP) intensity modulator operating at 1.3 μm with pulse amplitude modulation formats for short reach transmission employing a digital to analog converter for the RF signal generator, enabling pulse shaping and precompensation of the transmitter's frequency response. Details of the SiP Mach-Zehnder interfometer are presented. We study the system performance at various bit rates, PAM orders and propagation distances. To the best of our knowledge, we report the first demonstration of a 112 Gb/s transmission over 10 km of SMF fiber operating below pre-FEC BER threshold of 3.8 × 10(-3) employing PAM-8 at 37.4 Gbaud using a fully packaged SiP modulator. An analytical model for the Q-factor metric applicable for multilevel PAM-N signaling is derived and accurately experimentally verified in the case of Gaussian noise limited detection. System performance is experimentally investigated and it is demonstrated that PAM order selection can be optimally chosen as a function of the desired throughput. We demonstrate the ability of the proposed transmitter to exhibit software-defined transmission for short reach applications by selecting PAM order, symbol rate and pulse shape.

The split architecture network assumes a logically centralized controller, which is physically separated from a large set of data plane forwarding switches. When the control plane becomes decoupled from the data plane, the requirement to the failure resilience and recovery mechanisms changes. In this work we investigate one of the most important practical issues in split architecture deployment, the placement of controllers in a given network. We first demonstrate that the location of controllers have high impact on the network resilience using a real network topology. Motivated by such observation, we propose a min-cut based controller placement algorithm and compare it with greedy based approach. Our simulation results show significant reliability improvements with an intelligent placement strategy. Our work is the first attempt on the resilience properties of a split architecture network.

Microservices represent a new architectural style where small and loosely coupled modules can be developed and deployed independently to compose an application. This architectural style brings various benefits such as maintainability and flexibility in scaling and aims at decreasing downtime in case of failure or upgrade. One of the enablers is Kubernetes, an open source platform that provides mechanisms for deploying, maintaining, and scaling containerized applications across a cluster of hosts. Moreover, Kubernetes enables healing through failure recovery actions to improve the availability of applications. As our ultimate goal is to devise architectures to enable high availability (HA) with Kubernetes for microservice based applications, in this paper we examine the availability achievable through Kubernetes under its default configuration. We have conducted a set of experiments which show that the service outage can be significantly higher than expected.

When trying to incorporate security into a program, software developers face either too much theoretical information that they cannot apply or exhaustive and discouraging recommendation lists. This article gives an overview of security concerns at each step of a project's life cycle.

Composite multipath fading/shadowing environments are frequently encountered in different realistic scenarios. These channels are generally modeled as a mixture of Nakagami-m multipath fading and log-normal shadowing. The resulting composite probability density function (pdf) is not available in closed form, thereby making the performance evaluation of communication links in these channels cumbersome. In this paper, we propose to model composite channels by the G-distribution. This pdf arises when the log-normal shadowing is substituted by the inverse-Gaussian one. This substitution will prove to be very accurate for several shadowing conditions. In this paper we conduct a performance evaluation of single-user communication systems operating in a composite channel. Our study starts by deriving an analytical expression for the outage probability. Then, we derive the moment generating function of the G-distribution, hence facilitating the calculation of average bit error probabilities. We also derive analytical expressions for the channel capacity for three adaptive transmission techniques, namely, i) optimal rate adaptation with constant power, ii) optimal power and rate adaptation, and iii) channel inversion with fixed rate.

Mobile networks are critical for today's social mobility and the Internet. More and more people are subscribing to mobile networks, which has led to substantial demands. The network operators need to find ways of meeting the huge demands. Since mobile network resources, such as spectrum, are expensive, there is a need for efficient management of network resources as well as finding a way to predict future use for network management and planning. Network planning is crucial for network operators to provide services that are both cost effective and have high degree of quality of service (QoS). The aim of this research is to apply data analysis techniques to support network operators to maximize the resource usage for network operators, that is, to prevent both under-provisioning and over-provisioning. Therefore, this paper investigates the prediction accuracy of machine learning techniques -- Multi-Layer Perceptron (MLP), Multi-Layer Perceptron with Weight Decay (MLPWD), and Support Vector Machines (SVM) -- using a dataset from a commercial trial mobile network. The experimental results show that SVM outperforms MLP and MLPWD in predicting the multidimensionality of the real-life network traffic data, while MLPWD has better accuracy in predicting the unidimensional data. Our experimental results can help network operators predict future demands and facilitate provisioning and placement of mobile network resources for effective resource management.

The next generation of mobile systems is expected to support multiple radio access technologies, as well as diverse types of terminals, including mobile phones, personal digital assistants, and laptops, as well as personal area, moving, and sensor networks. Thus, future wireless systems will not only continue to break technological barriers in terms of new air interface capabilities, higher bit rates, mobility, security, and QoS management, but will present new end-to-end scenarios in which applications access services over multiple L2 hops and multiple IP networks. The term always best connected refers to the concept of defining a set of access selection criteria and mechanisms that allow users to get connected to various services in a nearly optimal manner. Providing QoS in this type of heterogeneous multihop environment is a challenging task because applications may be completely unaware of them scenario and the underlying layer 2 technologies that can be quite different at different hops. For instance, some wireless links may have scarce resources and highly optimized QoS mechanisms; others may not support explicit QoS handling at all. In this article we consider the use of IP-level QoS signaling as a key component to support the end-to-end QoS for various applications. We propose a small set of application programmer- and wirelesslink-friendly IP QoS parameters (wireless hints) and illustrate the use of these in a specific WLAN-to-cellular handover situation. We conclude that the proposed model, signaling protocol, and wireless information elements can efficiently support QoS in heterogeneous mobile environments.

A reconfigurable antenna (RA) capable of steering its beam into the hemisphere corresponding to θ ∈ {-40°, 0°, 40°}, φ ∈ {0°, 45°, 90°, -45°}, and of changing 3 dB beamwidth, where θ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> dB ∈ (40°, 100°), φ ∈ {45°, 90°, -45°} for broadside direction is presented. The RA operating in 5 GHz band consists of a driven patch antenna with a parasitic layer placed above it. The upper surface of the parasitic layer has two pixelated metallic strips, where each strip has four pixels. The pixels connected via p-i-n diode switches enable to change the current distribution on the antenna providing the desired modes of operation. A prototype RA was characterized indicating an average gain of 8 dB. Measured and simulated impedance and radiation patterns agreed well. The proposed RA offers an efficient solution by using less number of switches compared to other RAs. The system level simulations for a 5G orthogonal frequency division multiple access system show that the RA improves capacity/coverage tradeoff significantly, where the RA modes and users are jointly determined to create proper beamwidth and directivity at the access point antennas. For a hotspot scenario, the presented RA provided 29% coverage and 16% capacity gain concurrently.