Cost and Response Time Simulation for Web-based Applications on Mobile Channels

When considering the addition of a mobile presentation channel to an existing web-based application, a key question that has to be answered even before development begins is how the mobile channel’s characteristics will impact the user experience and the cost of using the application. If either of these factors is outside acceptable limits, economical considerations may forbid adding the channels, even if it would be feasible from a purely technical perspective. Both of these factors depend considerably on two metrics: The time required to transmit data over the mobile network, and the volume transmitted. The PETTICOAT method presented in this paper uses the dialog flow model and web server log files of an existing application to identify typical interaction sequences and to compile volume statistics, which are then run through a tool that simulates the volume and time that would be incurred by executing the interaction sequences on a mobile channel. From the simulated volume and time data, we can then calculate the cost of accessing the application on a mobile channel

Performance tuning and cost discovery of mobile web-based applications

When considering the addition of a mobile presentation channel to an existing web-based application, project managers should know how the mobile channel|s characteristics will impact the user experience and the cost of using the application, even before development begins. The PETTICOAT (Performance Tuning and cost discovery of mobile web-based Applications) approach presented here provides decision-makers with indicators on the economical feasibility of mobile channel development. In a nutshell, it involves analysing interaction patterns on the existing stationary channel, identifying key business processes among them, measuring the time and data volume incurred in their execution, and then simulating how the same interaction patterns would run when subjected to the frame conditions of a mobile channel. As a result of the simulation, we then gain time and volume projections for those interaction patterns that allow us to estimate the costs incurred by executing certain business processes on different mobile channels

Analysis of GPRS Limitations

The General Packet Radio Service (GPRS) is a new standard for mobile data communications, which is implemented under the existing infrastructure of Global System for Mobile Communications (GSM). The promise capability of handling Internet Protocol traffic enables instant and constant connection to global network regardless of location and time. With its packet-based nature, the new technology facilitates new applications in wireless communications that have not been available previously. Nonetheless, there are numbers of limitations that have to be taken into consideration b~fore this technology can be implemented commercially. Despite all arguments and challenges, the GPRS system is here to stay and evolving towards the third generation mobile communications. This report covers the background of the GPRS and discusses the issues involved in implementing this current technology besides considering the deployment of third generation networks beyond GPRS

Cost Simulation and Performance Optimization of Web-based Applications on Mobile Channels

When considering the addition of a mobile presentation channel to an existing web-based application, a key question that has to be answered even before development begins is how the mobile channel's characteristics will impact the user experience and the cost of using the application. If either of these factors is outside acceptable limits, economical considerations may forbid adding the channels, even if it would be feasible from a purely technical perspective. Both of these factors depend considerably on two metrics: The time required to transmit data over the mobile network, and the volume transmitted. The PETTICOAT method presented in this paper uses the dialog flow model and web server log files of an existing application to identify typical interaction sequences and to compile volume statistics, which are then run through a tool that simulates the volume and time that would be incurred by executing the interaction sequences on a mobile channel. From the simulated volume and time data, we can then calculate the cost of accessing the application on a mobile channel, and derive suitable approaches for optimizing cost and response times

Soft handover issues in radio resource management for 3G WCDMA networks

PhDMobile terminals allow users to access services while on the move. This unique feature has driven the rapid growth in the mobile network industry, changing it from a new technology into a massive industry within less than two decades. Handover is the essential functionality for dealing with the mobility of the mobile users. Compared with the conventional hard handover employed in the GSM mobile networks, the soft handover used in IS-95 and being proposed for 3G has better performance on both link and system level. Previous work on soft handover has led to several algorithms being proposed and extensive research has been conducted on the performance analysis and parameters optimisation of these algorithms. Most of the previous analysis focused on the uplink direction. However, in future mobile networks, the downlink is more likely to be the bottleneck of the system capacity because of the asymmetric nature of new services, such as Internet traffic. In this thesis, an in-depth study of the soft handover effects on the downlink direction of WCDMA networks is carried out, leading to a new method of optimising soft handover for maximising the downlink capacity and a new power control approach

Size-based scheduling under terminal constraints in cellular systems

Langattomien verkkojen suosio on lisääntynyt samalla, kun tiedonsiirtonopeudet ovat kolmannen sukupolven matkapuhelinverkkojen (3G) ja niiden kehitysversioiden, kuten High Speed Downlink Packet Access (HSDPA), myötä kasvaneet. Solukkoverkoissa kaikkia käyttäjiä ei voida palvella yhtäaikaa, ja järjestelmän on aikataulutettava lähetykset eli tehtävä päätös siitä, missä järjestyksessä käyttäjiä palvellaan. HSDPA -järjestelmissä eri käyttäjien lähetykset erotellaan toisistaan koodien avulla, tällöin puhutaan koodijakokanavoinnista (Code Division Multiple Access, CDMA). HSDPA -järjestelmässä päätelaitteet on ryhmitelty sen perusteella, montaako koodia laite pystyy enimmillään käyttämään. Tässä työssä tutkitaan aikataulutuspolitiikan vaikutusta langattoman järjestelmän suorituskykyyn päätelaiterajoitusten vallitessa. Aikataulutuspolitiikkaa muuttamalla on mahdollista parantaa järjestelmän suorituskykyä, mikä kiinnostaa erityisesti langattomien verkkojen tapauksessa. Aiemmin on osoitettu, että niin kutsuttua Shortest Remaining Processing Time (SRPT) -politiikkaa noudattamalla M/G/1 jonotusjärjestelmän keskiviive voidaan minimoida. Päätelaiterajoitusten huomioiminen johtaa ns. monen palvelimen jonomalleihin, joiden optimaalisia aikataulutuspolitiikkoja ei tunneta. Langatonta solukkoverkkoa on simuloitu vuotasolla, ja tulosten perusteella SRPT -politiikkaa käyttämällä järjestelmän suorituskyky vaikuttaa paranevan myös siinä tapauksessa, että päätelaiterajoitukset huomioidaan. Suorituskyvyn muutos riippuu järjestelmän kuormituksesta ja järjestelmässä olevien koodien kokonaismäärästä. Suurin parannus suorituskykyyn saavutetaan hyvin korkeilla kuorman arvoilla.The traffic volume of mobile data has been increasing while the third generation of mobile communication systems (3G) and its evolution versions such as High Speed Downlink Packet Access (HSDPA) have increased the transmission rates of mobile networks. In cellular networks it is not possible to serve all users simultaneously and the system schedules the transmissions by selecting the service order of users in the system. In HSDPA-like systems the transmissions of users are separated by codes, that is the systems are based on Code Division Multiple Access (CDMA) technology. User devices are categorized by the number of codes each device is able to use at maximum. In this thesis, the scheduling aspect of improving the performance of wireless systems is examined. The service order of jobs in the system is defined by the scheduling policy. By changing this policy, it is possible to change the behaviour of the system considerably. Earlier it has been proven that the Shortest Remaining Processing Time (SRPT) policy is the optimal way of minimizing the mean delay of the M/G/1 queue. In this thesis, the SRPT policy is under examination when terminal constraints are taken into account. This results in multi-server queuing models for which hardly any optimal scheduling results are known. The results achieved by simulating the wireless cellular system at flow level show that the performance of the system is improved by using SRPT instead of Processor Sharing, the fair baseline policy. The performance improvement depends on the load of the system together with the number of codes in the system. The performance improvement is higher when the system is under high loads

A block coprocessor for user data rate improvements to GPRS coding scheme 4

The general packet radio service (GPRS) has been developed to allow packet data to be transported efficiently over an existing circuit-switched radio network, such as GSM. The main application of GPRS are in transporting Internet protocol (IP) datagrams from web servers (for telemetry or for mobile Internet browsers). Four GPRS baseband coding schemes are defined to offer a trade-off in requested data rates versus propagation channel conditions. However, data rates in the order of > 100 kbits/s are only achievable if the simplest coding scheme is used (CS-4) which offers little error detection and correction (EDC) (requiring excellent SNR) and the receiver hardware is capable of full duplex which is not currently available in the consumer market. A simple EDC scheme to improve the GPRS block error rate (BLER) performance is presented, particularly for CS-4, however gains in other coding schemes are seen. For every GPRS radio block that is corrected by the EDC scheme, the block does not need to be retransmitted releasing bandwidth in the channel and improving the user's application data rate. As GPRS requires intensive processing in the baseband, a viable field programmable gate array (FPGA) solution is presented in this paper

Specifying and Verifying Requirements for Transmission of Medical Data in Public Networks

The purpose of this study is to identify and verify the necessary Quality of Service metrics in public networks for an existing remote patient monitoring system called Mobile Viewers. Therefore, any abnormalities can be detected beforehand and the application quality can be seen from the end user's point of view. The name Mobile Viewers refer to three different client applications: Web Viewers, Pocket Viewers and Cellular Viewers. The literature part of this thesis reviews the former research studies dedicated to network performance measurements in 3G, 2.5G and Wireless LAN networks. Based on the review, the most suitable measurement methods, tools, metrics and environments are selected to be utilised during this study. In the first part of the thesis work, passive live measurement tests are executed within UMTS, GPRS, LAN and Wireless LAN networks in order to find out the delay, jitter and packet loss metrics for the individual Mobile Viewers. As a result, GPRS presents the highest delay, jitter and packet loss values leading to poor application quality. The second part of the thesis study focuses on identifying the quality requirements for Mobile Viewers. Initially, a network emulator tool is employed to emulate the necessary delay, jitter and packet loss metrics in order to test the application quality under different network conditions. Additional subjective user defined tests are executed to assess the quality for each viewer client. Finally, the limit delay, packet loss and jitter values, where the application quality starts to degrade, are presented. Additional future work may be carried out by observing the Mobile Viewers' performances with higher technologies for instance, HSDPA. Furthermore, the conclusions derived from the analysis of the measurements and the proposed requirements for Mobile Viewers should be validated by additional experiments with different client devices, measurement tools and longer measurement periods