A Model Based Poisson Point Process for Downlink Cellular Networks Using Joint Scheduling

© 2019, Springer Science+Business Media, LLC, part of Springer Nature. This paper proposes a model based on a random cellular network to analyse performance of Joint Scheduling in which a typical user measures signal-to-interference-plus-noise ratio (SINR) on different resource blocks from K nearest BSs in order to find out the BS with the highest SINR to establish communication. The paper derives the general form of average coverage probability of a typical user in the case of K> 2 and its close-form expression in the case of K= 2. The analytical results which are verified by Monte Carlo simulation indicates that (1) using the Joint Scheduling can improve the user’s performance up to 34.88 % in the case of the path loss exponent α= 3 ; (2) the effect of the density of BSs on the user association probability is infinitesimal

Analytical Coverage Probability of a Typical User In Heterogeneous Cellular Networks

In a Poisson Point Process (PPP) network model, in which the locations of Base Stations (BSs) are randomly distributed according to a Spatial Poisson Process, has been recently used as a tractable stochastic model to analyse the performance of downlink Heterogeneous Cellular Networks (HCNs). The HCN is modelled as a multi-tier cellular network where each tier is characterised by the transmission power level, propagation path loss exponent and density of BSs. The current works on HCN enabling Intercell Interference Coordination (ICIC) technique usually deal with Strict Frequency Reuse (FR) or Soft FR with a reuse factor of $\Delta=1$ in a Rayleigh fading channel. It has been assumed that all Base Stations (BSs) transmit continuously which leads to a reduction on the impact of number of users and RBs on network performance. In this paper, the performance of Soft FR with a reuse factor of $\Delta>1$ in Rayleigh-Lognormal fading channel is evaluated. The impact of the number of users and Resource Blocks (RBs) on Intercell Interference (ICI) are presented for Round Robin scheduling and indicator functions. The results show that there are opposite trends between coverage probability of Cell-Center User (CCU) and Cell-Edge User (CEU)

Optimization of Number of Operators and Allocation of New Lines in an Oligopolistic Transit Market

This paper proposes a novel model for determining the optimal number of transit operators and the allocation of new lines in an oligopolistic transit market. The proposed model consists of three interrelated sub-models that are associated with three types of players; namely, transit authority, transit operators, and transit passengers. In practice, the operating cost per unit of transit line of each operator is decreasing in the number of lines that it operates. These effects which are referred to as the scale economies of transit operations are explicitly incorporated in the proposed model. On the basis of a logit-type transit passenger travel choice sub-model with elastic demand, the fares and frequencies of transit services are determined by an oligopolistic competitive equilibrium model (i. e. transit operator sub-model). The transit authority sub-model for optimization of the number of operators and the allocation of new lines is expressed as a 0-1 integer programming problem. It can be solved by an implicit enumeration heuristic solution algorithm. Numerical results show that both the scale economies and the market demand level have significant impacts on the optimal number of operators and the allocation schemes of new lines. Ignoring the effects of scale economies on transit operations may lead transit authorities to make biased decisions. © 2010 Springer Science+Business Media, LLC.postprin

Strict frequency reuse algorithm in random cellular networks

© 2016 IEEE. A Frequency Reuse algorithm which divides the users into two groups called Cell-Center Users (CCUs) and Cell- Edge Users (CEUs) is one of the most effective techniques that can mitigate the InterCell Interference as well as improve the spectrum efficiency in cellular networks. In literature, most of work on Strict Frequency Reuse algorithms in a Spatial Point Poisson network assumed that the reuse factor was 1 and there was either single user or single Resource Block (RB). Hence, the performance either CEU or CCU was discussed. In this paper, the performance of both types of users as well as total throughput of CEUs and CCUs are investigated. The analytical results indicate that most of users in Tier-1 are served as CCUs while the numbers of UEUs and CCUs in Tier-2 are similar

Bottleneck model revisited: An activity-based perspective

The timing of commuting trips made during morning and evening peaks has typically been investigated using Vickrey’s bottleneck model. However, in the conventional trip-based approach, the decisions that commuters make during the day about their activity schedules and time use are not explicitly considered. This study extends the bottleneck model to address the scheduling problem of commuters’ morning home-to-work and evening work-to-home journeys by using an activity-based approach. A day-long activity-travel scheduling model is proposed for the simultaneous determination of departure times for morning and evening commutes, together with allocations of time during the day among travel and activities undertaken at home or at the workplace. The proposed model maximizes the total net utility of the home-based tour, which is the difference between the benefits derived from participating in activities and the disutility incurred by travel between activity locations. The properties of the model solution are analytically explored and compared with the conventional bottleneck model for a special case with constant marginal-activity utility. For the case with linear marginal-activity utility, we develop a heuristic procedure to seek the equilibrium scheduling solution. We also explore the effects of marginal-work utility (or the employees’ average wage level) and of flexible work-hour schemes on the scheduling problem in relation to the morning and evening commuting tours.postprin

A closed-form expression for coverage probability of random cellular network in composite Rayleigh-Lognormal fading channels

© 2015 IEEE. Poisson point process (PPP) network model in which base stations (BSs) and users have Poisson distributions has been recently used to replace grid model for analyzing the performance of cellular networks. The closed-form for the coverage probability of a typical user that connects to the closest base station (BS), however, is only found in case of high transmission signal-to-noise (SNR) and only in Rayleigh fading. This paper derives a closed-form expression for the network coverage probability in composite Rayleigh-Lognormal for both low and high SNR. The analytical results show that the coverage probability is proportional to path loss exponent coefficient, and inversely proportional to exponential function of 1 over SNR. The analytical results are also verified by Monte Carlo simulations

Performance of soft frequency reuse in random cellular networks in Rayleigh-Lognormal fading channels

© 2016 IEEE. Soft Frequency Reuse (Soft FR) is an effective resource allocation technique that can improve the instantaneous received Signal-to-Interference-plus-Noise ratio (SINR) at a typical user and the spectrum efficiency. In this paper, the performance of Soft FR in Random Cellular network, where the locations of Base Stations (BSs) are random variables of Spatial Point Poisson Process (PPP), is investigated. While most of current works considered the network model with either single RB or frequency reuse with factor of 1, this work assume that the Soft FR with factor of Δ is deployed and there are M users and N (Δ > 1, M > 1, N > 1). The analytical and simulation results show that a network system with high frequency reuse factor create more InterCell Interference than that with low frequency reuse factor. Furthermore, in order to design the parameters to optimize Soft FR, the performance of the Cell-Edge and Cell-Center user should be considered together

Modelling and Simulation of Handover in Light Fidelity (Li-Fi) Network

© 2018 IEEE. The demand of a faster and more secure wireless communication system leads to the development of a new and innovated network in future. Light Fidelity (Li-Fi) is being researched to provide a better wireless network communication. In this communication technology, light from Light Emitting Diodes (LEDs) has been used for data transmission. The purpose of this research work is to investigate the performance of handover algorithms in a Li-Fi network. Two handover algorithms are Closest Access Point (AP) (CAP) and Maximum Channel Gain (MCG). MATLAB simulation results are presented to evaluate those two types of handover algorithms and to show the impacts of UE's rotation and movement on handover performance

Editorial: Advanced methods for public transport system management

published_or_final_versionSpringer Open Choice, 01 Dec 201

Development of a Bidirectional Pedestrian Stream Model with an Oblique Intersecting Angle

This paper establishes a mathematical model that can represent the conflicting effects of two pedestrian streams that have an oblique intersecting angle in a large crowd. In a previous paper, a controlled experiment in which two streams of pedestrians were asked to walk in designated directions was used to model the bidirectional pedestrian stream of certain intersecting angles. In this paper, the writers revisit that problem and apply the Bayesian inference method to calibrate an improved model with the controlled experiment data. Pedestrian movement data are also collected from a busy crosswalk by using a video observation approach. The two sets of data are used separately to calibrate the proposed model. With the calibrated model, the relationship between speed, density, and flow is studied in both the reference and conflicting streams, and a prediction is made regarding how these factors affected the interactions of moving pedestrian streams. It is found that the speed of one stream not only decreases with its total density, but also decreases with the ratio of its flow relative to the total flow, i.e., the speed of the pedestrians decreases if their stream changes from the major to minor stream. It is also observed that the maximum disruption that was induced by pedestrian flow from an intersecting angle occurs when the angle is approximately 135°.postprin