Driven by the rapid escalation of the wireless capacity requirements imposed by advanced multimedia applications (e.g., ultrahigh-definition video, virtual reality, etc.), as well as the dramatically increasing demand for user access required for the Internet of Things (IoT), the fifth-generation (5G) networks face challenges in terms of supporting large-scale heterogeneous data traffic. Nonorthogonal multiple access (NOMA), which has been recently proposed for the third-generation partnership projects long-term evolution advanced (3GPP-LTE-A), constitutes a promising technology of addressing the aforementioned challenges in 5G networks by accommodating several users within the same orthogonal resource block. By doing so, significant bandwidth efficiency enhancement can be attained over conventional orthogonal multiple-access (OMA) techniques. This motivated numerous researchers to dedicate substantial research contributions to this field. In this context, we provide a comprehensive overview of the state of the art in power-domain multiplexing-aided NOMA, with a focus on the theoretical NOMA principles, multiple-antenna-aided NOMA design, on the interplay between NOMA and cooperative transmission, on the resource control of NOMA, on the coexistence of NOMA with other emerging potential 5G techniques and on the comparison with other NOMA variants. We highlight the main advantages of power-domain multiplexing NOMA compared to other existing NOMA techniques. We summarize the challenges of existing research contributions of NOMA and provide potential solutions. Finally, we offer some design guidelines for NOMA systems and identify promising research opportunities for the future.

/pdf/nonorthogonal-multiple-access-for-5g-and-beyond-4vzewzi5qj.pdf

Nonorthogonal Multiple Access for 5G and Beyond

In this chapter, you will see how the simplex method simplifies when it is applied to a class of optimization problems that are known as “network flow models.” You will also see that if a network flow model has “integer-valued data,” the simplex method finds an optimal solution that is integer-valued.

Flows in Networks

Elements of Information Theory (2nd ed.). Thomas M. Cover and Joy A. Thomas

Providing ubiquitous connectivity to diverse device types is the key challenge for 5G and beyond 5G (B5G). Unmanned aerial vehicles (UAVs) are expected to be an important component of the upcoming wireless networks that can potentially facilitate wireless broadcast and support high rate transmissions. Compared to the communications with fixed infrastructure, UAV has salient attributes, such as flexible deployment, strong line-of-sight (LoS) connection links, and additional design degrees of freedom with the controlled mobility. In this paper, a comprehensive survey on UAV communication towards 5G/B5G wireless networks is presented. We first briefly introduce essential background and the space-air-ground integrated networks, as well as discuss related research challenges faced by the emerging integrated network architecture. We then provide an exhaustive review of various 5G techniques based on UAV platforms, which we categorize by different domains including physical layer, network layer, and joint communication, computing and caching. In addition, a great number of open research problems are outlined and identified as possible future research directions.

UAV Communications for 5G and Beyond: Recent Advances and Future Trends

Keywords: LTS3 Reference LTS-ARTICLE-2004-019 Record created on 2006-06-14, modified on 2016-08-08

Introduction to the special issue on multimedia implementation », IEEE Trans. On Circuits and Systems for Video Technology

The Internet of Things (IoT) will significantly change both industrial manufacturing and our daily lives. Data collection and 3-D positioning of IoT devices are two indispensable services of such networks. However, in conventional networks, only terrestrial base stations (BSs) are used to provide these two services. On the one hand, this leads to high energy consumption for devices transmitting at cell edges. On the other hand, terrestrial BSs are relatively close in height, resulting in poor performance of device positioning in elevation. Due to their high maneuverability and flexible deployment, unmanned aerial vehicles (UAVs) could be a promising technology to overcome the above shortcomings. In this article, we propose a novel UAV-assisted IoT network, in which a low-altitude UAV platform is employed as both a mobile data collector and an aerial anchor node to assist terrestrial BSs in data collection and device positioning. We aim to minimize the maximum energy consumption of all devices by jointly optimizing the UAV trajectory and devices’ transmission schedule over time, while ensuring the reliability of data collection and required 3-D positioning performance. This formulation is a mixed-integer nonconvex optimization problem, and an efficient differential evolution (DE)-based method is proposed for solving it. Numerical results demonstrate that the proposed network and the optimization method achieve significant performance gains in both energy-efficient data collection and 3-D device positioning, as compared with a conventional terrestrial IoT network.

/pdf/energy-efficient-data-collection-and-device-positioning-in-1xr9r3s8q3.pdf

Energy-Efficient Data Collection and Device Positioning in UAV-Assisted IoT

A novel kind of punctured polar codes is proposed in this paper The codes are constructed by certain constraints on both puncturing patterns and frozen sets such that the values of the punctured bits are known to the decoder As a result, the initialized log-likelihood ratios of the punctured bits can be set to infinity (or minus infinity), which guarantees a better decoding performance Furthermore, explicit puncturing patterns are designed for arbitrary code lengths The simulation results show that the proposed codes outperform the conventional punctured polar codes

A Novel Puncturing Scheme for Polar Codes

The presence of speckle noise in Synthetic Aperture Radar (SAR) images makes the interpretation of the contents difficult, thereby degrading the quality of the image. Therefore an efficient speckle noise removal technique needs to be sought. In this paper, we present a SAR image despeckling method known as Refined Lee Filter (RLF). The method is based on the well-known Lee filter. In this method the K-Nearest Neighbour (KNN) algorithm is employed to adjust the number of neighbour pixels used within the sliding window. Simulation results obtained from the performance evaluation metrics used showed that the proposed method improved the performance of the original Lee filter when they were both used to despeckle standard test images contaminated with speckle noise and SAR images.

SAR Image Despeckling Using Refined Lee Filter

This paper investigates the application of non-orthogonal multiple access (NOMA) to satellite communication network over Shadowed-Rician fading channels. The impact of imperfect successive interference cancellation (ipSIC) on NOMA-based satellite network is taken into consideration from the perspective of practical scenarios. We first derive new exact expressions of outage probability for the p-th terrestrial user and provide the corresponding asymptotic analysis results. The diversity order of zero and p is achieved by the p-th terrestrial user with ipSIC and perfect successive interference cancellation (pSIC), respectively. Finally, the presented simulation results show that: 1) On the condition of pSIC, the outage behaviors of NOMA-based satellite network are superior to that of orthogonal multiple access; 2) With the value of residual interference increasing, the outage performance of terrestrial users with ipSIC isbecoming worse seriously; and 3) In frequent light shadowing of Shadowed-Rician fading brings the better outage probability compared to frequent heavy and average shadowing.

Outage Behaviors of NOMA-Based Satellite Network Over Shadowed-Rician Fading Channels

The integration of multidimensional networks such as space, air and ground is the future trend of the IoT. In this article, we introduce the SAG IoT network paradigm, including its composition and network architecture. Network slicing, the core 5G technology, will be applied to the SAG IoT network. The wide use of mmWave and UAVs is to produce many new scenarios, and it is necessary to study the effects of UAVs on mmWave channels in these new scenarios. In addition, mmWave imaging technology can provide a basis for this research. Machine learning is an important new technology that can be widely used in the SAG IoT. Simulation and measurement are both important means of evaluating the performance of communication systems. To cope with the emerging new applications and technologies, a cloud-based modular simulation system is introduced for 5G and future IoTs; this system is characterized by high efficiency, flexible configuration and high precision.

Rongke Liu

Papers

Energy-Efficient Data Collection and Device Positioning in UAV-Assisted IoT

A Novel Puncturing Scheme for Polar Codes

SAR Image Despeckling Using Refined Lee Filter

Outage Behaviors of NOMA-Based Satellite Network Over Shadowed-Rician Fading Channels

Space-Air-Ground IoT Network and Related Key Technologies