Call Drop Rate Research Articles

Novel type-2 fuzzy logic technique for handover problems in a heterogeneous network

ABSTRACTSmall cells are deployed in the long-term evolution—advanced (LTE-A) data standard to satisfy rapidly increasing data rates at hotspots and enhance coverage in buildings. Small cells are low-cost, low-power nodes with limited coverage. With small cells, the more sophisticated network architecture increases the difficulty of dealing with mobility management. The conflict between traffic demands and network resources is also very important, and the signalling overhead (ping-pong) in the handover procedure should be considered in mobility management. With the aim of solving these issues, efficient handover algorithms are being used to enhance mobility management in small-cell networks. This article presents a new handover optimization algorithm for LTE-A networks based on fuzzy logic. It consists of selecting the optimum handover margins for both macro and small cells which are required for the handover process to optimize the performance metrics. The proposed handover optimization technique is evaluated and compared with two well-known handover algorithms. The results show that it achieves a minimum call drop rate and has a minimum number of handovers.

OPTIMIZATION OF HANDOVER IN MOBILE SYSTEM BY USING DYNAMIC GUARD CHANNEL METHOD

Handover process is a very essential process in the Global System for Mobile Communication system (GSM). Its study is one of the major key performance indicators in every GSM network, and its linked to the quality of service of an each service provider strives to attain. The failure of the handover process is regarded as the drop of quality of service which in turn dissatisfies the customers. This study, contributes more on improving call drop rate in general, reduce handover failure rate and thus save on upgrade costs, this will be beneficial to GSM service providers to easily optimize their network faults relating to the resource management. In this paper, dynamic guard channel algorithm is presented that was developed using JAVA Software. This algorithm prioritizes the handover calls over the new originated calls. All handover calls are ongoing calls and if they are dropped it causes frustrations. Matlab was used to compare simulated results to the other schemes by use of graphs and charts. From this paper we were able to establish and come up with a definitive solution to the handover crisis befalling telecommunication companies.

A comparative analysis of operational performance of Cellular Mobile Telephone Service Providers in the Delhi working area using an approach of fuzzy ELECTRE

The purpose of this research paper is to develop a framework to analyze the operational performance of cellular mobile telephone service providers (CMTSP) in the Delhi working area, India. Delhi area has the highest teledensity in India. The present study uses a fuzzy ELECTRE (Elimination and Choice Expressing Reality) approach to compare the performance of cellular mobile telephone service providers. The data for the analysis have been taken from the Telecom Regulatory Authority of India (TRAI), April–June 2015. Most of the data vary from one month to another. Therefore, these small ranges of variation in the data are incorporated in this study using the fuzzy number. Total six major telecom service providers are considered in this analysis. The findings of the study suggest that the performances of Airtel and Reliance communications are in the first rank; Vodafone and Idea are in the second rank; Aircel is in the third rank, and Mahanagar Telephone Nigam Limited (MTNL) is outranked by all the other service providers. The performance is analyzed on the basis of three major parameters consisting six criteria, i.e. network availability (Base Transceiver Station accumulated downtime), connection accessibility (call setup success rate, channel congestion, and traffic channel congestion), and connection retainability (call drop rate and connection with good voice quality). It has been observed that MTNL is outranked due to the highest traffic channel congestion and highest call drop rate. Using this framework, a decision maker can develop a strategy to improve the performance by benchmarking operational parameters. The research analysis is limited to only GSM (Global System for Mobile communication) service providers in the Delhi working area, including Ghaziabad, Noida, Faridabad, and Gurgaon.

Improvements of Call-drop Rate of CDMA Systems by Removing Spurious Emissions from UHF TV Broadcast Band

In this paper, we measured and analyzed interference signals which those unwanted signals are concerned to the adjacent RF interference signals inducing in the conventional 800MHz frequency band of CDMA systems. Especially, to evaluate the call-drop rate by removing the interference signals which spurious emissions are generated from the RF repeater and boosters of UHF TV broadcasting systems, we measured and analyzed call completing rate in a selected base station of CDMA system. From the measurement results, it can be seen that the spurious emissions generated from the UHF TV frequency band can cause the degradation of CDMA system performance. And it can be also seen that the drop-call rate of CDMA system can be markedly improved by removing the Intermodulation signals generated from the UHF TV broadcasting system. Finally, for helping the future research works, we suggest an example of filter specifications for removing the unwanted interference signals in the conventional 800MHz frequency band.

Analysis of Addax-Sinopec Outdoor Pathloss Behavior for WiFi and WiMAX Infrastructure

wireless environments, improper handover among mobile terminals can occur during micromobility due to various reasons. Once this takes place, the network Quality of Service (QoS) experiences degradation thereby increasing the call drop rate, creating latency problems and decreasing throughput. In such scenario, there is an urgent need to optimize network performance while utilizing network resources efficiently. Interestingly, various pathloss methods have been recently proposed to achieve relative network performance but these methods have high complexity and are cost effective. This work applied Hata model in spatial micromobility environment to evaluate the performance of mobile wireless access within Wifi and WiMax infrastructures. The work used Addax-Sinopec petroleum, a drilled deep exploratory oil well in Izombe, Oguta Local Government area situated in the south eastern part of Nigeria as a study testbed. From the testbed, technical data were collected for both a dedicated Wifi hotspot and Globacom WiMax infrastructure. The Wifi Tiplink access point, WiMax Distributed Control System (DCS) and a wireless router were all configured for the initial pathloss experimentation. MATLAB Script was developed for evaluation purposes considering the testbed. The results of the comparison show that WiMax offered a lower pathloss value compared with Wifi-network WiMax (IEEE 802.16). This makes WiMax optimal for wireless access communication with advantages such as being flexible, having long range, and offering high data capability.

Reduced Call Drop Rate in a 4G Network using Vertical Handoff Algorithm

Reduced Call Drop Rate in a 4G Network using Vertical Handoff Algorithm

English

This Work developed an accurate and efficient Antenna Isolation model to minimize interference in cohabiting Networks that used co-site parameters in the formulation of the mathematical model. The Work determined the maximum radius of co-site cell as1200metres and equally deduced the width of side-lobes in the received radiation pattern, whose minimization, using the 7th order Chebyshev Polynomials, minimized interference effects in the signal propagation path. Comparison of the Isolation models showed that the Traditional Antenna Isolation Model used by most Researchers, yield isolation loss of less than 75dB at the far-field distance of the interfered with CDMA 2000 1X Base Station (BS) antenna Receiver footprint with dropped calls of 42 and Call Drop Rate (CDR) of 13.33%; which was above the 13% Standard (3GPP TR, 2002). The use of the Proposed Isolation Model has the advantage of isolation improvement at no extra cost. Isolation loss of more than 99dB was attained at the far-field distance of the interfered with BS antenna Receiver and at the footprint, dropped calls of 31 and CDR of 9.84% were recorded.

Analysis of Dropped-Call Probability in Relay-Based High Speed Railway Environment

In poor coverage area of high-speed railway, the frequent handoff will increase the dropped-call rate. An approach to improving the quality of wireless communication is adding a relay between two base stations. Paper is about analyzing the dropped-call caused by handoff in this scene. This paper proposed a model for dropped-call probability through analyzing the handoff probability, same frequency interference and ping-pong handoff. Based on the simulation and comparison of the dropped-call model, we found that putting a relay between the base stations can significantly improve the dropped-call problem, and the peek rate of dropped-call decreased by an order of magnitude.

Performance Evaluation and Measurements of 3G Mobile Communication Networks: A Case Study

Communication networks have undergone rapid developments in the past few decades in many Sub-Saharan African countries. The increasing number of subscribers and demand for greater variety of services in these countries make it difficult for network operators to provide the service varieties subscribers want while maintaining acceptable levels of quality of service. This paper analyzes the radio network of cellular networks in terms of traffic distribution over the existing number of communication channels using MATLAB/Simulink. A scale-free user network, which takes into account user behavior in a realistic physical network, has been used to model a more realistic cause for call blockings in a typical cellular network deployment under a Sub-Saharan environment. Peak recorded traffic distribution was observed to have overwhelmed the existing number of channels provided by the network operators for some cells eventually leading to increase in call drop rates. This high call blocking probability was attributed to poor network monitoring by the network operators to match the ever changing traffic intensities.

Aproximación de la calidad de voz y cobertura en una red GSM de emergencia

En este documento se muestran los resultados obtenidos al medir los parámetros de calidad de voz en una solución propuesta de telecomunicaciones para la atención de desastres en situaciones de emergencia, haciendo uso de software libre para interconectar llamadas, protocolos de comunicaciones empleados en las redes GSM (<em>Global System Mobile</em>) en la banda DCS-1800 (<em>Digital Cellular Service</em> - 1800MHz), que facilita el uso de cualquier terminal móvil comercial, utilizando un USRP (<em>Universal Software Radio Peripheral</em>) en conjunto con sistema de telefonía IP basado en Asterisk. El USRP se encarga de emular la operación de una BTS (<em>Base Transceiver Station</em>) al ejecutar las funciones de un PBX (<em>Private Branch Exchange</em>), permitiendo la coordinación de las entidades responsables de responder y atender este tipo de emergencias. Las mediciones del desempeño de la red se realizaron a partir de tres parámetros probabilísticos: GoS (<em>Grade of service</em>), DCR (<em>Dropped Call Rate</em>) y MOS (<em>Mean Opinion Score</em>). Con el uso de 8 terminales y escogiendo un GoS del 2% se generó un tráfico de hasta 3,6 Erlang. Esta medición se realizó empleando modelos probabilísticos de Erlang B. Se realiza el comparativo de la cobertura de la red aplicando el modelo Okumura-Hata sin el uso de amplificadores.

A Practical Optimisation Method to Improve QOS and GOS-Based Key Performance Indicators in GSM Network Cell Cluster Environment

The delivering of both good quality of service (QoS) and Grade of Service (GoS) in any competitive mobile communication environment is a major factor to reducing subscribers’ churn rate. Therefore, it is important for wireless mobile network operators to ensure stability and efficiency by delivering a consistent, reliable and high-quality end user (subscriber) satisfaction. This can only be achieve by conducting a regular network performance monitoring and optimisation as it directly impacts the quality of the offered services and hence user satisfaction. In this paper, we present the results of network performance evaluation and optimisation of a GSM network on cell cluster-basis, in Asaba region, South East Nigeria. We employ a combination of essential key performance indicators such as dropped call rate, call setup success rate and outage call rate to examine overall QoS and GoS performance of the GSM network. Our results after network optimisation showed significant performance improvement in terms of call drop rate, call set up success rate, and call block rate across. Specifically, the end user satisfaction rate has increased from 94.45%, 87.74%, and 92.85% to 99.05%, 95.38% and 99.03% respectively across the three GSM cell clusters. The GoS is reduced from 3.33%, 6.60% and 2.38% to 0.00%, 3.70% and 0.00% respectively. Furthermore, ESA, which correspond end points service availability, has improved from 94.44%, 93.40% and 97.62% to 100%, 96.30% and 100% respectively. In addition, the average throughput has improved from 73.74kbits/s, 85.06kbits/s and 87.54kbits/s to 77.07kbits/s, 92.38kbits/s and 102kbits/s respectively across the three GSM cell clusters.

English

Mobile network communication system offers the users with seamless communication and this has caused wireless communication to increasingly become the preferred method of carrying multimedia traffic or messages such as voice, video, images, and data files. Time division multiple access (TDMA) is the multiple access scheme used in global system for mobile communication (GSM), while third generation (3G) system uses wideband-code division multiple access (W-CDMA). The former is designed majorly for voice and a little of data. Due to the increase in number of phone users and the services enjoyed by the users, there is higher demand for non-voice services, mobile extensions to fixed-line services and richer mobile content. This has caused the network operators to develop 3G system with the goal of providing a network infrastructure that can support a much broader range of services than existing systems in which its penetration level has reached market saturation. This paper presents a comparison of the two wireless systems performance based on their modulation techniques. From the constellation gotten, the two systems were analyzed and the analysis shows that W-CDMA (that is, 3G) provides a network infrastructure that can support a much broader range of services than existing systems (GSM) because the main forces behind development of the 3G have been driven by the second generation systems’ low performance data services, incompatible service in different parts of the world, and lack of capacity.   Key words: Time division multiple access (TDMA), wideband-code division multiple access (W-CDMA), call drop rate, call set-up success rate (CSSR), handover rate, constellation.

The Optimization of Inter cell Handover Dynamics in a GSM Network

Efficient Handover mechanism in a GSM network is one of the parameters critical to GSM network service quality (QoS) and customer satisfaction. Ongoing calls are being transferred through the process of handover from one cell to another as the users move through the coverage areas of the cellular systems. This research focuses on analyzing and optimizing intercell handover dynamics in Airtel Network in Kano. A three months call record sample data was used. Average call drop rate per cell was predicted to be six (6%). An optimal solution was provided using dynamic cutoff priority channel allocation scheme, this improves performance of handover dynamics when simulated. An object oriented simulation technique was employed using a JAVA variant NETBEANS 6.1 because of its moderate system resource requirement, fast and responsive user interface. The result shows that handover failure rate was reduced by an average of Ninety percent (90%) for varying loads. System validation was achieved by comparing the real and simulated load characteristics which produced striking similarities with a correlation coefficient of 0.9122.

Effects and Optimization Impact of Wireless Signal Loss for Subscribers in Lagos State

This paper presents the effects and optimization impact of wireless signal loss for subscribers in Lagos state, using 3G as a study. This paper is aimed at analyzing network coverage data obtained through drive testing on the investigated area to detect coverage holes or area with poor coverage. The collected data showed significantly where the problems were via pre drive test and analysis was performed to proffer solutions to identified problems. This was later confirmed with a post drive test. The Key Performance Indicators (KPI) which include Receive Signal Code Power(RSCP), Energy per chip to noise ratio(Ec/No), Speech Quality Index(SQI), User Equipment Transmit Power(UE Tx Power), Active Set number of members were analyzed and showed significant improvement after optimization where necessary. The RSCP coverage quality showed an appreciable improvement from 40% to over 76% of good coverage after optimization. Results after the optimization reveals that the Call Setup Success Rate increased from about 96% to about 98% and the Call Drop Rate reduced from 0.664% to 0.62 % out of 940 and 493 total number of calls attempts made during the pre and post drive test respectively. Besides, areas with more than three active set which could result into pilot pollution were identified and corrected by adjusting of the parameter (tilt) of the antenna involved.

Self‐optimizing neighbor cell list with dynamic threshold for handover purposes in networks with small cells

AbstractTo select a proper target cell for handover of mobile users, signal level of cells in user's neighborhood is scanned by a user equipment (UE). Cells assumed to be scanned are included in the so‐called neighbor cell list (NCL). Conventionally, the NCL is managed according to the probability of handover of users to a target cell with fixed threshold. Nevertheless, the size of NCL could be significant if this approach is applied to networks with small cells. In this paper, we exploit knowledge of handover probability among cells derived from a handover history to reduce the amount of scanned cells. We introduce dynamic adaptation of the amount of cells to be scanned according to the quality of signal of a serving cell, measured by the UE. We also investigate impact of relation between the handover probability and the signal level to maximize efficiency of this approach. Further, the NCL management considering either summarized handover history of all UE or individual history of each user is compared in our evaluations. As the results show, both methods notably reduce the amount of cells to be scanned, while call drop rate and outage of the users are still negligible as in the conventional way. Copyright © 2013 John Wiley & Sons, Ltd.

Mobile relay in LTE-advanced systems

Voice and data communications on high speed vehicles encounter bad channel condition, high call drop rate, serious signaling congestion and excessive power consumption of UE. Mobile relay technology which features on-board relay node is expected to improve the quality of service for passengers. However, the design for fixed relay in LTE-Advanced system cannot meet the requirements of mobile relay. In this article, the architecture for mobile relay is presented. The key techniques of supporting mobile relay are investigated, such as the group mobility, the local service support, the multi-RAT and RAN sharing, with the corresponding solutions. The potential system optimization, for example, the self-optimization network, power saving, measurement and system information acquisition are also presented where the efficiency of mobile relay can further be improved. Simulation and numerical results demonstrate the feasibility of the mobile relay.

Performance Evaluation of GSM Service Providers around Igbinedion University Campuses

A performance evaluation of GSM service providers (Globacom, MTN and Zain) was conducted in Okada, Edo State; home of Igbinedion University. The main research objective was ascertaining the Quality of Service (QoS) provision level and fulfillment of minimum industry QoS standards of GSM operators. The GSM Key Performance Indicators (KPIs) and technical parameters measured included: percentages of call set-up success rate, call set-up failure rate, post dialing delay (intra/inter-network), call drop rate, call retention rate and call completion rate; credit balance inquiry success and failure; SMS delivery failures, incorrect feedback and multiple billing; recharge cards loading success, loading error and loading incorrect feedback. The measurements were carried out at different geographical positions of the town at varying time intervals. Observations were also made on some other performance issues like network availability, voice quality, call setup phase, post dialing delay-elongation, weather influence and signaling/ feedback. The study revealed several levels of KPI achievements by the different networks with Globacom performing best, coming tops in twenty-three (23) indicators out of the thirty-seven (37) considered followed by Zain and then MTN. It also revealed that the networks achieved some NCC QoS benchmarks and failed in some other notable ones.

Performance Comparison of Protection Strategies in WDM Mesh Networks

Recent development in optical networking employing wavelength division multiplexing (WDM) fulfills the high bandwidth demand applications. Failure of such networks, leads to enormous data and revenue loss. Protection is one of the key techniques, which is used in designing survivable WDM networks. In this paper we compare dedicated and shared protection strategies employed inWDMmesh networks to protect optical networks failure, particularly fiber failure. Dijkstra’s shortest path algorithm is considered for carrying out simulations. The paper compares the performance of protection schemes, such as, dedicated path protection (DPP), shared path protection (SPP) and shared link protection (SLP) schemes. Capacity utilization, switching time and blocking probability are the parameters considered to measure the performance of the protection schemes. Simulation results show that, SPP is more efficient in terms of capacity utilization over DPP and SLP schemes, whereas, SLP offered better switching time than both DPP and SPP schemes. The average call drop rate is minimum for shared path protection scheme and maximum for shared link protection scheme.

Beacon signaling and its application to inter-frequency handoff in OFDMA cellular communications

This paper introduces a beacon coding and signaling technique and its application to handoff in OFDMA cellular communication networks. Beacon signaling provides an efficient alternative to the conventional tune-away approach for inter-carrier/frequency handoff. The proposed handoff technique transmits beacon pilots in other carrier frequencies in the network allowing for easy and early detection of neighboring cells, and fast and seamless handoffs in a multi-carrier synchronous or asynchronous deployment. The proposed technique thereby minimizes the call drop rate and interference due to delayed handoff.

BANDWIDTH RESERVATION ALGORITHM FOR WIRELESS CELLULAR NETWORKS

This paper presents an advanced bandwidth reservation technique to improve Quality of Service (QoS) by reducing the forced call termination during handoff. One solution to ensure continuity of on-going calls and reduce the forced call termination during handoff is to predict Mobile Station (MS) trajectory and do resource reservation in advance. So, we propose a new scheme that uses an accurate mobility prediction algorithm to predict MS next location and uses this data in bandwidth reservation scheme to improve QoS. The performance of the algorithm is evaluated via simulations. The simulation results show that our algorithm reduces handoff call drop rate without over reserving the resources hence it improves bandwidth utilization and reduces new call blocking rate.