Performance study of video streaming in commercial UMTS network

This paper studies the performance of a real-time application in a live Universal Mobile Telecommunication System (UMTS) network. In the study, special user equipment (UE) capable of collecting performance parameters such as throughput and bit error rate (BER) was used. Two scenarios are considered in this paper: typical scenario when soft handover (SHO) is enabled and an extreme scenario when a situation of cell edge is created by forcing the terminal to strictly connect to one cell. The experiment results show various aspects of practical implementations and protocols which are currently used in live UMTS network. In the typical scenario, when a code with a large spreading factor (SF) is in use, the required signal-to-noise ratio target (SIRT) is low. In the cell edge case, a code with high SF of 32 is used in a poor radio condition. There results are consistent with the relevant theory. © 2008 IEEE

Dynamic Almost Blank Subframe Scheme for Enhanced Intercell Interference Coordination in LTE-A Heterogeneous Networks

In LTE-A heterogeneous network, traffic load may be distributed unequally because the transmission power of macro eNodeB (eNB) is higher than pico eNB. To address the coverage problems resulting from nodes with different transmission powers, cell range expansion (CRE) technique has been proposed as a cell selection technique. However, in this case, the intercell interference (ICI) problem can occur on both data and control channels when users connect to pico eNB. To mitigate ICI problem, a new dynamic almost blank subframe (ABS) scheme is proposed in this paper. In this scheme, a fuzzy logic system is deployed to monitor the system performance and then obtain the required number of ABSs. Simulation results show that the cell throughput and user throughput can be improved using the proposed dynamic ABS scheme

Teaching about firewall concepts using the iNetwork simulator

The iNetwork Simulator is a software application created provides a user-friendly graphical interface for building and simulating basic communication networks. Such networks can comprise of devices such as workstations, servers, switches and routers. This project enhances the iNetwork Simulator application by allowing firewalls to be simulated. Firewalls play in integral part in the security infrastructure of many organisations (and individuals). Being able to interact with a virtual firewall would benefit many students with an interest in the security-related aspects of communication networks. The firewall component was implemented using the Microsoft .NET Framework and the C# programming language (the same platform used to originally develop the iNetwork Simulator application). The full software development lifecycle was followed during the course of this project. © 2006 IEEE

An adaptive step size power control with transmit power control command aided mobility estimation

Power control is one of the most important mechanisms influencing on the maximum capacity and performance of Wideband Code Division Multiple Access (WCDMA) systems. Power control algorithms used in Universal Mobile Telecommunication System (UMTS) are based on fixed step size algorithms. The algorithms adjust their transmitted power based on Transmit Power Control (TPC) commands. In this paper, we show that there is a significant correlation between TPC sequences and user mobility. We then introduce a new parameter called Consecutive TPC Ratio (CTR), which will be varied by user speeds. A new adaptive power control algorithm is also proposed. This new power control algorithm uses CTRs to adjust power control step sizes. The result shows that the proposed algorithm outperforms fixed step power control

A fuzzy Q-learning approach for enhanced intercell interference coordination in LTE-Advanced heterogeneous networks

© 2014 IEEE. Since the transmission power of macro eNodeB (eNB) is higher than pico eNB in long term evolution-advanced heterogeneous network, the coverage area of picocell is small. In order to address the coverage problem, cell range expansion (CRE) technique has been recently proposed. However, CRE can lead to the downlink interference problem on both data and control channels when users are connected to pico eNB. In order to mitigate the downlink interference problem, a new dynamic almost blank subframe (ABS) scheme is proposed in this paper. In this scheme, a fuzzy q-learning approach is used to find the optimum ABS value. Simulation results show that the system performance can be improved through the proposed scheme

Robust scheduling algorithm for Guaranteed Bit Rate services

This paper proposes a novel packet scheduling algorithm to overcome detrimental effects of channel impairments on the quality of service of delay-sensitive Guaranteed Bit Rate (GBR) services. The proposed algorithm prioritises the packets that require retransmission of Hybrid Automatic Repeat Request (HARQ) users compared to the packets of new users. The packets of new users are scheduled according to the Channel Quality Information (CQI), average throughput and packet delay information. Computer simulations have demonstrated that the proposed algorithm has 22.7% system capacity improvement over a well-known algorithm. It also tolerates for up to 200% delay of CQI and reduces the uplink signalling overhead by 150% compared to the well-known algorithm without compromising the quality of service requirements of the GBR services. Copyright © 2013 Inderscience Enterprises Ltd

Proportional fair scheduling with reduced feedback

An opportunistic feedback technique is proposed for proportional fair (PF) scheduling in a downlink multi-user system. This technique requires each mobile station, the scheduling metric of which is higher than a threshold, to send one-bit feedback for PF scheduling. The scheduler determines the optimal modulation and coding scheme for a scheduled user based on channel quality indicator (CQI) update, which is sent on a longer period than the scheduling period. The simulation results indicate that PF scheduling with the proposed update scheme can achieve similar performance as PF scheduling with full CQI feedback. The feedback overhead can be reduced in comparison with typical PF scheduling provided that an optimal CQI update period is chosen. © The Institution of Engineering and Technology 2009

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

Analysis of the influence to productivity of software corrective maintenance using an economic model

© 2014 IEEE. This paper presents an economic model for productivity of software corrective maintenance. The productivity is modeled using economic value of the maintenance process as the output, and the pre-committed fixed cost and variable cost as input. The relationship of the economic value and these cost components are modeled using analytical theory of investment. The values of corrective maintenance process are analyzed. A simulation approach is demonstrated to analyze the influences to the productivity in corrective maintenance. This approach provides a tool to identify and analyze the optimal parameters in productivity using the economic model and simulation

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)