scholarly journals Soft Mobility: Transparent Handover with Zero Handover Failure in User-Centric Networks

2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Yong Sun ◽  
Haoyan Wei ◽  
Shusheng Wang ◽  
Hongtao Zhang
Keyword(s):  
Current System ◽  
Reference Signal ◽  
Base Stations ◽  
Radio Link ◽  
Channel State ◽  
Promising Candidate ◽  
Link Failures ◽  
A Cell ◽  
Small Base ◽  
User Centric

User-centric network (UCN) is regarded as a promising candidate to approach the challenges of more radio link failures (RLFs) due to the ultradense deployment of small base stations (SBSs) and meet the requirements of ultrahigh throughput, ultrahigh reliability, and ultralow latency for the 6G system. In this paper, soft mobility is proposed for UCN with the split of control and user plane (C/U-plane) and shared physical cell identifier (PCI) to achieve the goal of zero handover failure (HOF) probability, where transparent handover (HO) within a cell is realized with user configuration duplication and measurement enhancement. Specifically, the cell is composed of several SBSs around the user, where one anchor SBS is selected for controlling, and others act as slave SBSs for transmission with duplicated UE configuration from the anchor SBS. Based on the proposed architecture, the user measures downlink channel quality for cells and SBSs distinguishingly, via SS/PBCH Block (SSB) and channel-state information-reference signal (CSI-RS), respectively, and then makes the HO decision. Results show that soft mobility can reduce the number of HOF by about 50% over the current system, and the HOF probability is lower than 1% for TTT = 40  ms and offset = − 1  dB.

scholarly journals Sdn in Edge Computing Based on Penguin Foraging Behaviour

2020 ◽  
Vol 9 (8) ◽  
pp. 34-37
Keyword(s):  
Foraging Behaviour ◽  
Search Algorithm ◽  
Base Station ◽  
Network Evolution ◽  
Small Cell ◽  
Edge Computing ◽  
Base Stations ◽  
High Coverage ◽  
A Cell ◽  
Small Base

Over the years usage of computational devices have been increased rapidly. 3G and 4G network evolution has helped in seamless usage of the modern devices. As the users are increasing rapidly and 4G spectrum is been congested way too fast. These situations resulted in development of 5G Spectrum by unlocking the millimetre waves. Milli meter Waves are originally shortrange waves and cannot be passed through heavy objects for these solution Small Base station concept has been implemented which provides high coverage and less latency while using. A small cell is basically a miniature base station that breaks up a cell site into much smaller pieces, and is a term that encompasses pico cells, micro cells, femto cells and can comprise of indoor/outdoor systems. For this implementation the SDN plays an important role for maintaining the connection between Base stations. Penguin foraging behaviour can be taken as a reference for the search algorithm in edge computing for getting faster results. Usually a penguin population comprises of several groups. Each group contains a number of penguins that varies depending on food availability in the corresponding foraging region. They feed as a team and follow their local guide which has fed on most food in the last dive. Similarly we follow the same process in small cell base station. Edge computing supports all devices simultaneous for processing and getting accurate results. They can be used for platform development for storage centric, server centric or even hybrid(storage-server) workloads.

Spectral Efficiency Self-Optimization through Dynamic User Clustering and Beam Steering

2016 ◽  
pp. 137-155
Author(s):  
Md Salik Parwez ◽  
Hasan Farooq ◽  
Ali Imran ◽  
Hazem Refai
Keyword(s):  
Spectral Efficiency ◽  
Large Scale ◽  
Optimization Problem ◽  
Focal Point ◽  
Beam Steering ◽  
Clustering Algorithms ◽  
Performance Comparison ◽  
Base Stations ◽  
User Clustering ◽  
A Cell

This paper presents a novel scheme for spectral efficiency (SE) optimization through clustering of users. By clustering users with respect to their geographical concentration we propose a solution for dynamic steering of antenna beam, i.e., antenna azimuth and tilt optimization with respect to the most focal point in a cell that would maximize overall SE in the system. The proposed framework thus introduces the notion of elastic cells that can be potential component of 5G networks. The proposed scheme decomposes large-scale system-wide optimization problem into small-scale local sub-problems and thus provides a low complexity solution for dynamic system wide optimization. Every sub-problem involves clustering of users to determine focal point of the cell for given user distribution in time and space, and determining new values of azimuth and tilt that would optimize the overall system SE performance. To this end, we propose three user clustering algorithms to transform a given user distribution into the focal points that can be used in optimization; the first is based on received signal to interference ratio (SIR) at the user; the second is based on received signal level (RSL) at the user; the third and final one is based on relative distances of users from the base stations. We also formulate and solve an optimization problem to determine optimal radii of clusters. The performances of proposed algorithms are evaluated through system level simulations. Performance comparison against benchmark where no elastic cell deployed, shows that a gain in spectral efficiency of up to 25% is possible depending upon user distribution in a cell.

scholarly journals An urban expressway forwarding scheme for cognitive Internet of vehicles

2020 ◽  
Vol 16 (3) ◽  
pp. 155014772091294
Author(s):  
Jing Wang ◽  
Huyin Zhang ◽  
Sheng Hao ◽  
Chuhao Fu
Keyword(s):  
Cognitive Radio ◽  
Traffic Safety ◽  
Smart Cities ◽  
Radio Spectrum ◽  
Base Stations ◽  
Radio Link ◽  
Integer Optimization ◽  
Internet Of Vehicles ◽  
Urban Expressway ◽  
Channel Availability

The Internet of vehicles is an essential component for building smart cities that can improve traffic safety and provide multimedia entertainment services. The cognitive radio–enabled Internet of vehicles was proposed to resolve the conflict between the increasing demand of Internet of vehicles applications and the limited spectrum resources. The multi-hop transmission is one of the most important issues in cognitive radio–enabled Internet of vehicles networks. Nevertheless, most existing forwarding solutions designed for the cognitive radio–enabled Internet of vehicles did not consider the urban expressway scenario, where primary base stations are densely installed with small coverage areas. In this case, it is difficult to ensure that the sender and the receiver of the same cognitive radio link have similar channel availability statistics, which makes cognitive radio links more likely to be interrupted. To address this challenge, we develop a multi-hop forwarding scheme to minimize the end-to-end delay for such networks. We first formulate the delay minimization problem as a non-linear integer optimization problem. Then, we propose an approach to select the relay candidates by jointly considering the high mobility of vehicles and the unique cognitive radio spectrum usage distributions in urban expressway scenarios. Finally, we propose the low-latency forwarding strategies by considering the channel availability and the delay cost of different situations of relay candidates. Simulations show the advantages of our proposed scheme, compared with state-of-art methods.

scholarly journals Optimizing a Secure Two-Way Network with Non-Linear SWIPT, Channel Uncertainty, and a Hidden Eavesdropper

Electronics ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 1222
Author(s):  
Pham Viet Tuan ◽  
Pham Ngoc Son ◽  
Tran Trung Duy ◽  
Sang Quang Nguyen ◽  
Van Quang Binh Ngo ◽  
...  
Keyword(s):  
Base Stations ◽  
Artificial Noise ◽  
Power Splitting ◽  
Transmission Power ◽  
Channel State ◽  
Downlink Beamforming ◽  
Non Linear ◽  
Channel Information ◽  
Downlink Channels

In this paper, the optimization of downlink beamforming vectors, uplink transmission power, and power-splitting factors is investigated for a secure two-way SWIPT network in the presence of a hidden eavesdropper and non-linear energy harvesting circuits over both perfect and imperfect channels. The eavesdropper is inactive, so its channel information is not available at the base stations (BSs). The purpose of artificial noise is to create downlink interference with the hidden eavesdropper as much as possible, while satisfying the quality of service for two-way communications. For perfect downlink channels, the semidefinite relaxation (SDR) technique is exploited, and the optimal matrices are proven to satisfy rank-1 conditions, thus providing the optimal beamforming vectors. For imperfect downlink channel state information, we propose an iterative algorithm with a penalty function to obtain the approximate rank-1 matrices. On uplink, we attain the optimal transmission power for users receiving maximum ratio transmission beamforming at the BSs. Eventually, the numerical experiments show the superiority of the proposed scheme, compared to a conventional scheme, in terms of signal-to-interference-plus-noise ratio at the eavesdropper.

scholarly journals A Security Scheme of 5G Ultradense Network Based on the Implicit Certificate

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Zhonglin Chen ◽  
Shanzhi Chen ◽  
Hui Xu ◽  
Bo Hu
Keyword(s):  
Data Communication ◽  
Base Stations ◽  
System Capacity ◽  
Communication Model ◽  
Spatial Reuse ◽  
Network Bandwidth ◽  
Security Problem ◽  
Small Base ◽  
And Performance ◽  
Security Communication

The ultradense network (UDN) is one of the most promising technologies in the fifth generation (5G) to address the network system capacity issue. It can enhance spatial reuse through the flexible, intensive deployment of small base stations. A universal 5G UDN architecture is necessary to realize the autonomous and dynamic deployment of small base stations. However, the security of the 5G UDN is still in its infancy, and the data communication security among the network entities is facing new challenges. In this paper, we proposed a new security based on implicit certificate (IC) scheme; the scheme solves the security problem among the access points (APs) in a dynamic APs group (APG) and between the AP and user equipment (UE). We present each phase regarding how two network entities obtain the Elliptic Curve Qu-Vanstone (ECQV) implicit certificate scheme, verify each other’s identity, and share keys in an UDN. Finally, we extensively analyze our lightweight security communication model in terms of security and performance. The simulation on network bandwidth evaluation is also conducted to prove the efficiency of the solution.

scholarly journals Transmission Scheme with Limited Channel State Information Feedback for 3D MIMO System

2015 ◽  
Vol 2015 ◽  
pp. 1-12 ◽  
Author(s):  
Xing Li ◽  
Hui Zhao ◽  
Long Zhao ◽  
Wenxiu Zhao ◽  
Senyao Zheng
Keyword(s):  
Channel State Information ◽  
Mimo System ◽  
Reference Signal ◽  
Base Station ◽  
Information Feedback ◽  
Transmission Scheme ◽  
Channel State ◽  
State Information ◽  
3D Mimo ◽  
Channel State Information Feedback

Three-dimensional (3D) multiple-input multiple-output (MIMO) system can exploit the spatial degree of freedom in vertical dimension and can significantly improve system performance compared with 2D transmission scheme. However, in the actual frequency division duplex (FDD) transmission mode, the large overhead of the reference signal and channel state information (CSI) feedback would become a barrier for performance improvement of 3D MIMO system with the significantly increased number of transmit antennas. To deal with these problems, this paper proposes a new transmission scheme of the channel state information-reference signal (CSI-RS), where the CSI-RS is precoded with 3D beamforming vectors and composed of two components: long-term CSI-RS and short-term CSI-RS. For the purpose of conducting efficient transmission in widely used FDD system, we also propose a corresponding limited channel state information feedback scheme. Moreover, multiuser pairing and scheduling criteria based on the design of the CSI-RS are proposed to realize the multiuser transmission. We have investigated multiple options for 3D MIMO codebook scheme and finally adopt the Kronecker product-based codebook (KPC) for precoding operation at the base station (BS). Simulation results demonstrate that our proposed scheme for the 3D MIMO system achieves a better tradeoff between resource overhead and throughput performance.

scholarly journals MSE Minimized Joint Transmission in Coordinated MultiPoint Systems with Sparse Feedback and Constrained Backhaul Requirements

2020 ◽  
Author(s):  
Mohammad Bagher Nezafati ◽  
Mehrdad Taki ◽  
Tommy Svensson
Keyword(s):  
Base Stations ◽  
Channel State ◽  
Coordinated Multipoint ◽  
System A ◽  
Backhaul Link ◽  
Central Coordination ◽  
The Mean ◽  
Value Decomposition ◽  
The Cost ◽  
Joint Transmission

Abstract In a joint transmission coordinated multipoint (JT-CoMP) system, a shared spectrum is utilized by all neighbor cells. In the downlink, a group of base stations (BSs) coordinately transmit the users’ data to avoid serious interference at the users in the boundary of the cells, thus substantially improving area fairness. However, this comes at the cost of high feedback and backhaul load; In a frequency division duplex (FDD) system, all users at the cell boundaries have to collect and send feedback of the downlink channel state information (CSI). In centralized JT-CoMP, although with capabilities for perfect coordination, a central coordination node (CCN) have to send the computed precoding weights and corresponding data to all cells which can overwhelm the backhaul resources. In this paper, we design a JT-CoMP scheme, by which the sum of the mean square error (MSE) at the boundary users is minimized, while feedback and backhaul loads are constrained and the load is balanced between BSs. Our design is based on the singular value decomposition (SVD) of CSI matrix and optimization of a binary link selection matrix to provide sparse feedback - constrained backhaul link. For comparison, we adopt the previously presented schemes for feedback and backhaul reduction in the physical layer. Extensive numerical evaluations show that the proposed scheme can reduce the MSE with at least 25% , compared to the adopted and existing schemes.

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