scholarly journals A Novel Random Access Algorithm for Very High Frequency Data Exchange (VDE)

2020 ◽  
Vol 8 (2) ◽  
pp. 83
Author(s):  
Yi Jiang ◽  
Yang Zheng ◽  
Junsen Wang
Keyword(s):  
Data Exchange ◽  
Random Access ◽  
Traffic Load ◽  
Media Access Control ◽  
Identification System ◽  
Contention Resolution ◽  
International Telecommunication Union ◽  
Access Channel ◽  
Simulation Results ◽  
Random Access Algorithm

VHF Data Exchange System (VDES) is considered as an important component of the future maritime communication system by the International Maritime Organization (IMO). On the basis of the existing Automatic Identification System (AIS), VDES adds the other two higher capacity subsystems: Application Specific Message (ASM) and VHF Data Exchange (VDE). The Random Access Channel (RACH) of VDE was first introduced in the International Telecommunication Union (ITU) Recommendation M.2092-0. As the slot planning principle of RACH in VDE is by interval, which is significantly different from the continuous slot map for access algorithms in AIS, the existing slot access algorithms cannot meet the requirements of VDE. The simulation results show that the VDE slot map can reduce the normalized throughput of the existing algorithm by 39%. A novel random access algorithm called Adaptive Traffic Load Contention Resolution Diversity Slotted ALOHA (ATL-CRDSA) is proposed in this paper. The algorithm combines the load control strategy and contention resolution scheme to overcome the challenges of the new RACH of VDE. Simulation results show that ATL-CRDSA has remarkable improvement on RACH, making it very efficient and providing low latency of the packets. The insights gained from this study may be of assistance to the Media Access Control (MAC) layer design for upcoming versions of VDES standard.

Multi-Bit NVRAMs Using Quantum Dot Gate Access Channel

2017 ◽  
Vol 26 (03) ◽  
pp. 1740014
Author(s):  
Murali Lingalugari ◽  
Pik-Yiu Chan ◽  
John Chandy ◽  
Evan Heller ◽  
Faquir Jain
Keyword(s):  
Quantum Dot ◽  
Random Access ◽  
Random Access Memory ◽  
Floating Gate ◽  
Access Memory ◽  
Storage And Retrieval ◽  
Access Channel ◽  
Array Architecture ◽  
Simulation Results ◽  
Long Channel

This paper presents a quantum dot access channel nonvolatile random access memory (QDAC-NVRAM) which has comparable write and erase times to conventional random access memories but consumes less power and has a smaller footprint. We have fabricated long-channel (W/L=15μm/10μm) nonvolatile random access memories (NVRAMs) with 4μs erase times. These devices are CMOS-compatible and employ novel quantum dot access channel (QDAC) which enables fast storage and retrieval of charge from the floating gate layer. In addition, QDNVRAMs are shown to be capable of storing multiple-bits and potentially scalable to sub 22nm. We are also presenting the simulation results. This paper also presents a memory array architecture using QDAC-NVRAMs.

scholarly journals RADB: Random Access with Differentiated Barring for Latency-Constrained Applications in NB-IoT Network

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Yiming Miao ◽  
Yuanwen Tian ◽  
Jingjing Cheng ◽  
M. Shamim Hossain ◽  
Ahmed Ghoneim
Keyword(s):  
Internet Of Things ◽  
Optimization Algorithm ◽  
Random Access ◽  
Wide Area ◽  
Network Congestion ◽  
Huge Amount ◽  
Access Channel ◽  
Random Access Channel ◽  
Simulation Results ◽  
Internet Of Things Technology

With the development of LPWA (Low Power Wide Area) technology, the emerging NB-IoT (Narrowband Internet of Things) technology is becoming popular with wide area and low-data-rate services. In order to achieve objectives such as huge amount of connection and wide area coverage within NB-IoT, the problem of network congestion generated by random access of numerous devices should be solved. In this paper, we first introduce the background of NB-IoT and investigate the research on random access optimization algorithm. Then we summarize relevant features of NB-IoT uplink and narrowband physical random access channel and design random access with differentiated barring (RADB), which can improve the insufficiency of traditional dynamic access class barring method. At last, the algorithms proposed in this paper are realized with established NB-IoT model using OPNET Modeler platform, and simulations are conducted. The simulation results show that RADB is able to effectively solve preamble request conflict generated by random access of numerous devices and preferentially provide efficient and reliable random access for latency-sensitive devices.

scholarly journals A Poisson Process-Based Random Access Channel for 5G and Beyond Networks

Mathematics ◽  
2021 ◽  
Vol 9 (5) ◽  
pp. 508
Author(s):  
Alaa Omran Almagrabi ◽  
Rashid Ali ◽  
Daniyal Alghazzawi ◽  
Abdullah AlBarakati ◽  
Tahir Khurshaid
Keyword(s):  
Poisson Process ◽  
Random Access ◽  
Communication Technologies ◽  
Channel Access ◽  
Access Channel ◽  
Machine Type Communications ◽  
Equal Chance ◽  
Random Access Channel ◽  
Access Mechanisms

The 5th generation (5G) wireless networks propose to address a variety of usage scenarios, such as enhanced mobile broadband (eMBB), massive machine-type communications (mMTC), and ultra-reliable low-latency communications (URLLC). Due to the exponential increase in the user equipment (UE) devices of wireless communication technologies, 5G and beyond networks (B5G) expect to support far higher user density and far lower latency than currently deployed cellular technologies, like long-term evolution-Advanced (LTE-A). However, one of the critical challenges for B5G is finding a clever way for various channel access mechanisms to maintain dense UE deployments. Random access channel (RACH) is a mandatory procedure for the UEs to connect with the evolved node B (eNB). The performance of the RACH directly affects the performance of the entire network. Currently, RACH uses a uniform distribution-based (UD) random access to prevent a possible network collision among multiple UEs attempting to access channel resources. However, in a UD-based channel access, every UE has an equal chance to choose a similar contention preamble close to the expected value, which causes an increase in the collision among the UEs. Therefore, in this paper, we propose a Poisson process-based RACH (2PRACH) alternative to a UD-based RACH. A Poisson process-based distribution, such as exponential distribution, disperses the random preambles between two bounds in a Poisson point method, where random variables occur continuously and independently with a constant parametric rate. In this way, our proposed 2PRACH approach distributes the UEs in a probability distribution of a parametric collection. Simulation results show that the shift of RACH from UD-based channel access to a Poisson process-based distribution enhances the reliability and lowers the network’s latency.

Random-Access Multilevel Storage in Phase Change Memory by Staircase-Like Pulse Programming

2011 ◽  
Vol 497 ◽  
pp. 111-115
Author(s):  
Ryota Kobayashi ◽  
Tomoyuki Noguchi ◽  
You Yin ◽  
Sumio Hosaka
Keyword(s):  
Phase Change ◽  
Phase Change Memory ◽  
Random Access ◽  
Experimental Results ◽  
Device Resistance ◽  
Multilevel Storage ◽  
Simulation Results ◽  
Change Memory

We have investigated random-access multilevel storage in phase change memory by staircase-like pulse programming. Staircase-like pulse consists of first sub-pulse and second sub-pulse. Our simulation exhibited that any resistance levels are expected to be randomly accessed by controlling the crystallization with different widths of second sub-pulset2. Based on the simulation results, we did experiment on staircase-like pulse programming. Experimental results showed that the device resistance gradually increased with reducing second sub-pulset2to 0 ns. In other words, random access to any resistance levels was demonstrated to be possible simply by changingt2.

scholarly journals Multiple Slot Reservation for Rapid Data Traffic Transmission in the Satellite Random Access Channel

2015 ◽  
Vol 40 (10) ◽  
pp. 1889-1899 ◽  
Author(s):  
Yun-sung Lee ◽  
Jin-seok Lee ◽  
Jae-sung Lim ◽  
Hyung-won Park ◽  
Hong-jun Noh
Keyword(s):  
Random Access ◽  
Data Traffic ◽  
Access Channel ◽  
Random Access Channel

scholarly journals An Analysis of Possibilities How the Collision Between M/V ‘Baltic Ace’ and M/V ‘Corvus J’ Could Have Been Avoided

2016 ◽  
Vol 23 (1) ◽  
pp. 121-134 ◽  
Author(s):  
Eric Kulbiej ◽  
Piotr Wołejsza
Keyword(s):  
Decision Support ◽  
Decision Support System ◽  
Support System ◽  
Automatic Identification ◽  
Identification System ◽  
Automatic Identification System ◽  
Simulation Results

Abstract The report presents the simulation results of collision between m/v ‘Baltic Ace’ and m/v ‘Corvus J’. The analysis was performed by means of navigation decision support system (NDSS) in collision situations. This system (NAVDEC) works out anti-collision manoeuvre using AIS (Automatic Identification System) and ARPA (Automatic Radar Plotting Aids) data. Then they are processed by specialized computing algorithms and presented to the operator on a display in the alphanumeric and graphic forms. The data on the specific navigational situation from the report of Bahamas Maritime Authority was used for the generation of signals transmitted to NDSS as a sequence of NMEA strings.

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