scholarly journals A Transmit Beamforming and Nulling Approach with Distributed Scheduling to Improve Cell Edge Throughput

2010 ◽  
Vol 2010 ◽  
pp. 1-9
Author(s):  
Wendy C. Wong ◽  
Qinghua Li ◽  
Shilpa Talwar
Keyword(s):  
Building Block ◽  
Interference Mitigation ◽  
Base Stations ◽  
Distributed Scheduling ◽  
System Throughput ◽  
Basic Building Block ◽  
Transmit Beamforming ◽  
Cell Edge ◽  
Speed Up

We propose a transmit scheme for WiMAX systems, where multiple base stations (BSs) employ downlink transmit beamforming and nulling for interference mitigation, with minimal coordination amongst BSs. This scheme improves system throughput and robustness, by increasing cell edge and overall cell throughputs by 68% and 19%, respectively, and by delivering improvement for mobile speed up to 60 km/h. First, cell edge users suffering from severe interferences are identified. Next, the RRM unit allocates resource to serving cell edge users only. BSs will schedule to serve their cell edge users independently using the allocated resources by the RRM. A special uplink sounding region is designed for BSs to learn the interference environment and form proper beams and nulls. The nulls formed towards users served by other BSs reduced interference from a BS towards these users and is the basic building block of our algorithm.

Scheduling Algorithm for High-Mobility User in LTE Downlink System

2014 ◽  
Vol 644-650 ◽  
pp. 2143-2146
Author(s):  
Jun Hong Ni ◽  
Yi Zhou ◽  
Zhen Dong Zhao ◽  
Peng Peng ◽  
Rui Ju Xiao
Keyword(s):  
Computer Simulation ◽  
Scheduling Algorithm ◽  
High Mobility ◽  
Base Stations ◽  
System Throughput ◽  
Frequency Diversity ◽  
Cell Edge ◽  
Downlink System ◽  
Cell Edge User

Frequency diversity scheduling allocates whole system bandwidth to a user in order to conquer deep fading of the sub-band when user with high-mobility. Though OFDMA technology mitigates interference of users in same cell, it increases interference of cell edge user as base stations use same frequency. Thus, we developed a frequency diversity fairness scheduling algorithm to balance fairness of cell center user and cell edge user. It is demonstrated by computer simulation that the proposed algorithm increases user fairness of the system with same system throughput and fairness between cell edge user and cell center user. It also points out that the algorithm proposed has the same complexity with the frequency diversity scheduling algorithm.

scholarly journals The Future of the Basic Building Block of Telecommunications Network

2020 ◽  
Author(s):  
Ibraheem Kateeb ◽  
Larry Burton ◽  
Naser El-Bathy ◽  
Michael Peluso
Keyword(s):  
Building Block ◽  
Basic Building Block ◽  
The Future ◽  
Telecommunications Network

Implementation of types of VCO

2021 ◽  
Vol 9 (8) ◽  
pp. 2972-2678
Author(s):  
Akshata O. Kattimani
Keyword(s):  
Frequency Shift ◽  
Building Block ◽  
Relaxation Oscillator ◽  
Phase Locked Loop ◽  
Frequency Synthesizers ◽  
Ring Oscillator ◽  
Electronic Systems ◽  
Basic Building Block ◽  
Colpitts Oscillator ◽  
Shift Keying

Abstract: A Voltage Controlled Divider (VCO) is a basic building block in most of the electronic systems. Phase-locked loop (PLL), tone synthesizers, Frequency Shift Keying (FSK), frequency synthesizers, etc make use of VCO’s to generate an oscillating frequency that can be decided with the help of components. Voltage Controlled Divider can be implemented for analog applications. The project proposes three types of VCO using Electric tool and LT Spice XVII tool. The three VCO’s that are implemented are CMOS Ring Oscillator, Colpitts Oscillator and Relaxation Oscillator. These circuits generate two oscillating frequencies that is decided by the circult components. Keywords: Voltage Controlled Divider (VCO), CMOS Ring Oscillator, Colpitts Oscillator, Relaxation Oscillator, oscillating frequency.

Measurement: The Basic Building Block of Research

2020 ◽  
pp. 13-37
Author(s):  
David Weisburd ◽  
Chester Britt ◽  
David B. Wilson ◽  
Alese Wooditch
Keyword(s):  
Building Block ◽  
Basic Building Block

Optical Communication with Invisible Photons

2020 ◽  
pp. 217-226
Author(s):  
M. Suhail Zubairy
Keyword(s):  
Optical Communication ◽  
Building Block ◽  
Communication Protocol ◽  
Zehnder Interferometer ◽  
Transmission Channel ◽  
Basic Building Block ◽  
Obvious Feature ◽  
Interaction Free Measurement ◽  
Mach Zehnder Interferometer

It has always been a self-evident and obvious feature of any kind of communication that there should be an exchange of objects like photons or electrons between the sender and the receiver to convey any information. In this chapter a protocol is presented in which information is transmitted between a sender and receiver with no particles in the transmission channel. The basic building block of this counterfactual communication protocol, the Mach–Zehnder interferometer, is discussed. The concept of interaction-free measurement is also introduced.

scholarly journals A Fast Link Initialization Protocol for Beam-Steering based Cellular Backhaul Systems

2015 ◽  
Vol 7 (2) ◽  
pp. 113
Author(s):  
Markus Petri ◽  
Marcus Ehrig ◽  
Markus Günther
Keyword(s):  
State Of The Art ◽  
Beam Steering ◽  
Small Cell ◽  
Base Stations ◽  
Data Traffic ◽  
Mobile Data ◽  
User Expectations ◽  
Network Topologies ◽  
Speed Up ◽  
Directive Antennas

<p>To deal with the enormous increase of mobile data traffic, new cellular network topologies are necessary. The reduction of cell area and the usage of light-weighted base stations serving only a handful of users, commonly known as the small cell approach, seems to be a suitable solution addressing changes in user expectations and usage scenarios. This paper is an extended version of [1], where current challenges of small cell deployments were presented from a backhaul perspective. A mesh-type backhaul network topology based on beam-steering millimeter-wave systems was proposed as a future-proof solution. In this paper, we focus on a link initialization protocol for beam-steering with highly directive antennas. Special requirements and problems for link setup are analyzed. Based on that, a fast protocol for link initialization is presented and it is evaluated in terms of the resulting initialization speed-up compared to state-of-the-art solutions. Furthermore, a potential approach for extending the fast link initialization protocol to support point-to-multipoint connections is given.</p>

scholarly journals Clustering and Auction-Based Power Allocation Algorithm for Energy Efficiency Maximization in Multi-Cell Multi-Carrier NOMA Networks

2019 ◽  
Vol 9 (23) ◽  
pp. 5034 ◽  
Author(s):  
Abuzar B. M. Adam ◽  
Xiaoyu Wan ◽  
Zhengqiang Wang
Keyword(s):  
Energy Efficiency ◽  
Power Allocation ◽  
Cooperative Game ◽  
Multiple Access ◽  
Optimization Problem ◽  
Interference Mitigation ◽  
Base Stations ◽  
Frequency Division ◽  
Simulation Results ◽  
Inter Cell Interference

In this paper, we investigate the energy efficiency (EE) maximization in multi-cell multi-carrier non-orthogonal multiple access (MCMC-NOMA) networks. To achieve this goal, an optimization problem is formulated then the solution is divided into two parts. First, we investigate the inter-cell interference mitigation and then we propose an auction-based non-cooperative game for power allocation for base stations. Finally, to guarantee the rate requirements for users, power is allocated fairly to users. The simulation results show that the proposed scheme has the best performance compared with the existing NOMA-based fractional transmit power allocation (FTPA) and the conventional orthogonal frequency division multiple access (OFDMA).

Sparse Associative Memory

2019 ◽  
Vol 31 (5) ◽  
pp. 998-1014 ◽  
Author(s):  
Heiko Hoffmann
Keyword(s):  
Associative Memory ◽  
Building Block ◽  
Basic Building Block ◽  
Small Probability ◽  
Hopfield Networks ◽  
New Model ◽  
Brain Functions ◽  
Memory Efficiency ◽  
Low Efficiency

It is still unknown how associative biological memories operate. Hopfield networks are popular models of associative memory, but they suffer from spurious memories and low efficiency. Here, we present a new model of an associative memory that overcomes these deficiencies. We call this model sparse associative memory (SAM) because it is based on sparse projections from neural patterns to pattern-specific neurons. These sparse projections have been shown to be sufficient to uniquely encode a neural pattern. Based on this principle, we investigate theoretically and in simulation our SAM model, which turns out to have high memory efficiency and a vanishingly small probability of spurious memories. This model may serve as a basic building block of brain functions involving associative memory.

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