Open Topics

Vol. 75, n° 1-2, January-February 2020
Content available on Springerlink

Exploiting capture and interference cancellation for uplink random multiple access in 5G millimeter-wave networks

Fulvio Babich1, Massimiliano Comisso1, Alessandro Cuttin1, Fabio Ricciato2
(1) Department of Engineering and Architecture, University of Trieste, Trieste, Italy
(2) Faculty of Computer and Information Science, University of Ljubljana, Ljubljana, Slovenia

Abstract The forthcoming 5G technology aims to provide massive device connectivity and ultra-high capacity with reduced latency and costs. These features will be enabled by increasing the density of the base stations, using millimeter-wave (mmWave) bands, massive multiple-input multiple-output systems, and non-orthogonal multiple access techniques. The ability to support a large number of terminals in a small area is in fact a great challenge to guarantee massive access. In this context, this paper proposes a new receiver model for the uplink of 5G mmWave cellular networks. The receiver, called Iterative Decoding and Interference Cancellation (IDIC), is based on the Slotted Aloha (SA) protocol and exploits the capture effect alongside the successive IC process to resolve packet collisions. A 5G propagation scenario, modeled according to recent mmWave channel measurements, is used to compare IDIC with the widely adopted Contention Resolution Diversity SA (CRDSA) scheme to show the performance gain of IDIC, when elements of practical relevance, like imperfect cancellation and receive power diversity, are considered. The impact of packet and power diversity is also investigated to derive the preferable uplink random access strategy that maximizes the system throughput according to the offered channel load.

Keywords  Random access · Successive interference cancellation · Iterative decoding · Capture

Multidimensional frequency estimation using LU decomposition eigenvector–based algorithm

Mohamed M. M. Omar1, Khaled A. Eskaf2, Basel A. Ghreiwati1
(1) Department of Electronic and Communication Engineering, Arab Academy for Science and Technology & Maritime, Egypt
(2) Department of Computer Science, Arab Academy for Science and Technology & Maritime, Egypt

Abstract Many algorithms have been proposed for multidimensional frequency estimation from a single snapshot or multiple snapshots of data mixture. Most of these algorithms fail when one or more identical frequencies are found in certain dimensions. In this paper, a multidimensional frequency estimation technique from a single datum snapshot is proposed. It applies LU decomposition (Gaussian Elimination) on an eigenvector-based algorithm for multidimensional frequency estimation. This proposed technique is simulated using a MATLAB code. The average root mean square error (RMSE) is investigated as a performance measure of the proposed technique. A comparison between original eigenvector-based (traditional) and the proposed techniques is introduced. The simulation results show that the RMSE of the proposed technique is less than the original one, and it has a more efficient solution for an identical frequency case but at the expense of complexity.

Keywords  Eigenvalue decomposition . Least mean square errors . Multidimensional frequency estimation . Singular value decomposition

Low-latency and high-throughput software turbo decoders on multi-core architectures

Bertrand Le Gal, Christophe Jego
IMS Laboratory, CNRS 5218, Univ. Bordeaux, Bordeaux INP, France

Abstract In the last few years, with the advent of a software-defined radio (SDR), the processor cores were stated to be an efficient solution to execute the physical layer components. Indeed, multi-core architectures provide both high-processing performance and flexibility, such that they are used in current base station systems instead of dedicated FPGA or ASIC devices. Currently, an extension of the SDR concept is running. Indeed, cloud platforms become attractive for the virtualization of radio access network functions. Actually, they improve the efficiency of the computational resource usage, and thus the global power efficiency. However, the implementation of a physical layer on a Cloud-RAN platform as discussed by Wubben and Paul (2016); Checko et al. (JAMA 17(1):405–426, 2015); Inc (2015); and Wubben et al. (JAMA 31(6):35–44, 2014) or FlexRAN platform as discussed by Wilson (2018); Foukas et al. (2017); Corp. (2017); Foukas et al. (2016) is a challenging task according to the drastic latency and throughput constraints as discussed by Yu et al. (2017) and Parvez (2018). Processing latencies from 10 μ s up to hundred of μ s are required for future digital communication systems. In this context, most of works about software implementations of ECC applications is based on massive frame parallelism to reach high throughput. Nonetheless, they produce unacceptable decoding latencies. In this paper, a new turbo decoder parallelization approach is proposed for x86 multi-core processors. It provides both: high-throughput and low-latency performances. In comparison with all CPU- and GPU-related works, the following results are observed: shorter processing latency, higher throughput, and lower energy consumption. Regarding to the best state-of-the-art x86 software implementations, 1.5 × to 2 × throughput improvements are reached, whereas a latency reduction of 50 × and an energy reduction of 2 × are observed.

Keywords  Turbo code · Multi-core · SIMD · High throughput · Low latency

Context-aware parallel handover optimization in heterogeneous wireless networks

Fatma A. Al Emam1, Mohamed E. Nasr2, Sherif E. Kishk1,2
(1) Electronics and Communications Engineering Department, Faculty of Engineering, Mansoura University, Egypt
(2) Electronics and Communications Engineering Department, Faculty of Engineering, Tanta University, Egypt

Abstract The key idea of this paper is to a use cross-layer triggering concept in order to control the vertical handover (VHO) in heterogeneous networks. Current mobility management protocols could not handle the ever-growing quality of service (QoS) demand for connected mobile nodes (MNs). Motivated by addressed challenging problems, the proposed multi-layer parallel handover optimization (MPHO) is capable of handling application awareness in its decision process. Each layer in the protocol stack implements its own decision mechanisms in response to environmental changes. Independent decisions may lead to un-optimal operation while reacting to the same event. MPHO coordinates triggered actions using a centralized controller. MPHO utilizes dynamic attributes to reduce HO latencies and signaling overheads with a more advanced coordination logic. It contains a prediction module that utilizes MN mobility patterns. Evaluation results validate the achieved enhancements with a smaller HO failure rate and increased throughput. MPHO achieves improvements in terms of perceived quality and delay constraints.

Keywords  Video streaming . Heterogeneous network .Vertical handover . Quality of service . Cross-layer . Context-based

Space-time code selection via particle swarm optimization

Dimas Mavares T.1, Miguel Oropeza2, Reinaldo Velásquez3
(1) Departamento de Electrónica y Ciencias de la Computación, Pontificia Universidad Javeriana, Colombia
(2) ABB Stonefield Works, Oulton Rd, Stone, ST15 0RS, UK
(3) Universidad de Carabobo, Valencia, Venezuela

Abstract In this paper, the space-time code selection technique for multiple-inputs single-output systems is optimized using particle swarm optimization. We considered both variable-rate and constant-rate strategies. For a variable-rate technique, we address the problems of minimizing the bit-error rate for a given throughput objective and maximizing the throughput for a given bit-error rate objective. For a constant-rate technique, we address the problem of minimizing the bit-error rate. Results show that it is possible to find BER and throughput values close to those required when using a variable-rate technique with optimized threshold levels. For the constant-rate technique, we obtain considerable energy to noise gains when using optimized threshold levels.

Keywords  Space-time code selection · Transmit diversity · MIMO · Particle swarm optimization · PSO

VIRAL: coupling congestion control with fair video quality metric

Tuan Tran Thai1, Emmanuel Lochin2, Jérôme Lacan2
(1) Expway, Paris, France
(2) ISAE-SUPAERO, Université de Toulouse, France

Abstract Video streaming is often carried out by congestion controlled transport protocols to preserve network sustainability. However, the success of the growth of such non-live video flows is linked to the user quality of experience. Thus, one possible solution is to deploy complex quality of service systems inside the core network. Another possibility would be to keep the end-to-end principle while making aware transport protocols of video quality rather than throughput. The objective of this article is to investigate the latter by proposing a novel transport mechanism which targets video quality fairness among video flows. Our proposal, called VIRAL for virtual rate-quality curve, allows congestion controlled transport protocols to provide fairness in terms of both throughput and video quality. VIRAL is compliant with any rate-based congestion control mechanisms that enable a smooth sending rate for multimedia applications. Implemented inside TFRC a TCP-friendly protocol, we show that VIRAL enables both intra-fairness between video flows in terms of video quality and inter-fairness in terms of throughput between TCP and video flows.

Keywords  Video streaming · Congestion control · Flow rate fairness · Video quality fairness

Traffic load–based cell selection for APCO25 conventional–based professional mobile radio

Saadet Simay Yılmaz1, Berna Özbek1, Murat Taş2, Sıdıka Bengür2

(1) Department of Electrical and Electronics Engineering, Izmir Institute of Technology, Izmir, Turkey
(2) ASELSAN A.Ş, 06370 Yenimahalle, Ankara, Turkey

Abstract  Wireless communication between public safety officers is very important to transmit voice or data during emergency crises. When the public communication networks cannot provide services during crises, disasters, and high traffic cases, Professional or private mobile radio (PMR) such as Association of Public Safety Communications Officials (APCO25) conventional systems are needed to improve the service quality and to provide uninterrupted service to the users. In this paper, we propose traffic-based cell selection algorithms for the APCO25 conventional systems to attach users to base stations in a balanced manner to reduce waiting time while establishing a connection. The simulation results of the proposed traffic load–based cell selection algorithms are illustrated in terms of the RSSI measurements counter, the number of connection requests, the average waiting time, and the number of re-selections for the APCO25 conventional systems.

Keywords  Cell selection · Cell re-selection · APCO25 · PMR · Traffic aware

Optical wireless multiple-input multiple-output system based on avalanche photodiode receiver

Hao Du, Guoning Xu

Academy of Opto-Electronics, Chinese Academy of Sciences, Beijing 100094, China

Abstract  With the rising demand for high data-transmission rates, optical wireless communication (OWC) is considered one of the particularly appropriate solutions. In this paper, an avalanche photodiode (APD)-based optical wireless configuration is used to approximate the receiver output. This paper also presents bit error rate (BER) evaluation statistics compared with the theoretical results for optical wireless multiple-input multiple-output (MIMO) communication systems. In particular, the simulated results show that the BER of a 4 × 4 MIMO system is significantly lower than that of other APD systems (over 10 times better when the mean energy is higher than − 165 dBJ). To summarize, the OWC-MIMO system shows enormous potential in the high-speed data-transmission field.

Keywords  APD receiver . Optical wireless communication . MIMOsystem