Analysis of Session Establishment Signaling Delay in IP Multimedia Subsystem

Abstract. This paper investigates and analyzes SIP delay in the session establishment signaling procedure in the IMS system. We investigate the delay for end-to-end link scenarios such as WiMAX-to-WiMAX, UMTS-to-UMTS, UMTS-to-WiMAX and vice versa. The analyses consider three types of delays: transmission delay, processing delay and queuing delay. The obtained results show that the main delay of session establishment signaling process is due to the processing delay. In addition, the lower channel rate in the UMTS network as well as IMS service rate has significant impact to the session establishment signaling delay

Voice Quality of VoIP in High Availability Environment

The development of telecommunication technology specified the Internet Protocol (IP) based technology for the next generation network. Voice over Internet Protocol (VoIP) has been introduced to overcome future telephony demand. However, these rapid changes encountered some issues, and the most critical is how to provide the services availability and reliability equally to circuit based telephony. Virtualization is widely used not only for hardware efficiency and maintenance, but also for High Availability support. Virtualized environment provides the ability among servers to migrate or replicate into another machine, even when they are running their services, which is known as Live Migration. In this paper, the voice quality of VoIP service when running on the High Availability system in virtualized environment is studied and examined. The objective analysis by using quality of services (QoS) attributes is conducted as well as the subjective analysis using Mean Opinion Score (MOS). The work utilizes Xen® Hypervisor with modified Remus extensions to provide the High Availability environment. Remus approach using checkpoint based is deployed to copy the primary server to the backup server. A range of 40ms – 900ms has been applied as time interval of checkpoint. The results show that the mean jitter is 9,98 ms, packet loss 3,12% and MOS 3.61 for Remus 400ms checkpoint. MOS with different checkpoint time interval is also presented

Self-Organisation Network (SON) Dengan Mekanisme Load Balancing

Load balancing is one of the mechanism used in the self-organization network (SON) to balance the traffic at the overloaded base station with the adjacent low-loaded base station. Load balancing is done by adjusting the handover parameters (metric) to obtain the optimal traffic balance. In this work, the adjusted parameters are the capacity of the cell. Cell capacity is strongly influenced by the bandwidth, modulation type, and the bit rate used by the user. The performance of load balancing was tested by a simulation and network test-bed measurement. The testing results on the Long-Term Evolution Advanced network showed the greater the bandwidth the greater the capacity of the cell. Moreover, the larger type of modulation, the cell capacity will also be greater. On the other hand, the greater bit rate used by the user, then the cell capacity will decrease. The calculation analysis of cell capacity is taken as the basic operation for load balancing procedure. A load balancing process algorithm is introduced to describe the mentioned procedure. The algorithm also considers the ping-pong effect that might occur due to the delay on the handover process

Self-Management of Disaster Risk and Uncertainty: The Role of Preventive Health in Building Disaster Resilience

One of the great challenges facing human systems today is how to prepare for, manage, and adapt successfully to the profound and rapid changes wreaked by disasters. Wellington, New Zealand, is a capital city at significant risk of devastating earthquake and tsunami, potentially requiring mass evacuations with little or short notice. Subsequent hardship and suffering due to widespread property damage and infrastructure failure could cause large areas of the Wellington Region to become uninhabitable for weeks to months. Previous research has shown that positive health and well-being are associated with disaster-resilient outcomes. Preventing adverse outcomes before disaster strikes, through developing strengths-based skill sets in health-protective attitudes and behaviours, is increasingly advocated in disaster research, practise, and management. This study hypothesised that well-being constructs involving an affective heuristic play vital roles in pathways to resilience as proximal determinants of health-protective behaviours. Specifically, this study examined the importance of health-related quality of life and subjective well-being in motivating evacuation preparedness, measured in a community sample (n=695) drawn from the general adult population of Wellington’s isolated eastern suburbs. Using a quantitative epidemiological approach, the study measured the prevalence of key quality of life indicators (physical and mental health, emotional well-being or “Sense of Coherence”, spiritual well-being, social well-being, and life satisfaction) using validated psychometric scales; analysed the strengths of association between these indicators and the level of evacuation preparedness at categorical and continuous levels of measurement; and tested the predictive power of the model to explain the variance in evacuation preparedness activity. This is the first study known to examine multi-dimensional positive health and global well-being as resilient processes for engaging in evacuation preparedness behaviour. A cross-sectional study design and quantitative survey were used to collect self-report data on the study variables; a postal questionnaire was fielded between November 2008 and March 2009 to a sampling frame developed through multi-stage cluster randomisation. The survey response rate was 28.5%, yielding a margin of error of +/- 3.8% with 95% confidence and 80% statistical power to detect a true correlation coefficient of 0.11 or greater. In addition to the primary study variables, data were collected on demographic and ancillary variables relating to contextual factors in the physical environment (risk perception of physical and personal vulnerability to disaster) and the social environment (through the construct of self-determination), and other measures of disaster preparedness. These data are reserved for future analyses. Results of correlational and regression analyses for the primary study variables show that Wellingtonians are highly individualistic in how their well-being influences their preparedness, and a majority are taking inadequate action to build their resilience to future disaster from earthquake- or tsunami-triggered evacuation. At a population level, the conceptual multi-dimensional model of health-related quality of life and global well-being tested in this study shows a positive association with evacuation preparedness at statistically significant levels. However, it must be emphasised that the strength of this relationship is weak, accounting for only 5-7% of the variability in evacuation preparedness. No single dimension of health-related quality of life or well-being stands out as a strong predictor of preparedness. The strongest associations for preparedness are in a positive direction for spiritual well-being, emotional well-being, and life satisfaction; all involve a sense of existential meaningfulness. Spiritual well-being is the only quality of life variable making a statistically significant unique contribution to explaining the variance observed in the regression models. Physical health status is weakly associated with preparedness in a negative direction at a continuous level of measurement. No association was found at statistically significant levels for mental health status and social well-being. These findings indicate that engaging in evacuation preparedness is a very complex, holistic, yet individualised decision-making process, and likely involves highly subjective considerations for what is personally relevant. Gender is not a factor. Those 18-24 years of age are least likely to prepare and evacuation preparedness increases with age. Multidimensional health and global well-being are important constructs to consider in disaster resilience for both pre-event and post-event timeframes. This work indicates a need for promoting self-management of risk and building resilience by incorporating a sense of personal meaning and importance into preparedness actions, and for future research into further understanding preparedness motivations

ARQ Mechanism in HSDPA

Two principal features of the MAC-hs protocol include retransmissions of erroneous blocks and in-sequence data delivery to the upper layer. The first function is provided through a HARQ mechanism. The second function is achieved with the help of sliding transmission/receiving window and by using a specific numbering. In this paper, the MAC-hs performance for different sliding window sizes, timer values and number of retransmission attempts are investigated. Simulations show that values of these parameters have to be carefully set up in order to prevent incorrect block discards at the receiver side

Les mécanismes de fiabilisation (protocoles ARQ) et leur adaptation dans les réseaux radiomobiles de 3G

The UMTS 3G system (3rd generation cellular system) is designed to offer a packet switched mode for data transfers in parallel to a circuit switched mode. This feature was planned since the beginning of 3G studies, contrary to 2G ones (such as the GSM system). To provide reliable data transfers, protocols implementing ARQ (Automatic Repeat reQuest) mechanisms are needed. We study ARQ protocols that can simultaneously be activated at different levels of the global UMTS protocol architecture: RLC (Radio Link Control), TCP (Transmission Control Protocol) and MAC-hs (Medium Access Control-high speed). A study of new features of the UMTS ARQ mechanisms as well as possibilities of their enrichments is studied. The stacking of ARQ mechanisms represents a risk of interactions between them. We analyze some of these interactionsLes réseaux radiomobiles de 3ème generation, tel que l'UMTS (Universal Mobile Telecommunications System) ont été prévus, dès le début de leur conception, pour offrir un mode paquet aussi bien qu'un mode circuit. Pour fiabiliser les transmissions de données en mode paquet, il faut mettre en uvre des protocoles disposant de la technique ARQ (Automatic Repeat reQuest). L'objet de cette thèse est l'étude des protocoles ARQ qui peuvent être activés dans l'architecture protocolaire globale de l'UMTS. Cela nous amène à étudier les couches contenant les protocoles ou entités suivantes : RLC (Radio Link Control), TCP (Transmission Control Protocol) et MAC-hs (Medium Access Control-high speed). L'étude des nouvelles caractéristiques des protocoles ARQ de l'UMTS ainsi que la possibilité de leur enrichissement est effectuée. L'empilement des mécanismes ARQ présente des risques d'interactions dont certains sont analysés

Les mécanismes de fiabilisation (protocoles ARQ) et leur adaptation dans les réseaux radiomobiles de 3G

The UMTS 3G system (3rd generation cellular system) is designed to offer a packet switched mode for data transfers in parallel to a circuit switched mode. This feature was planned since the beginning of 3G studies, contrary to 2G ones (such as the GSM system). To provide reliable data transfers, protocols implementing ARQ (Automatic Repeat reQuest) mechanisms are needed. We study ARQ protocols that can simultaneously be activated at different levels of the global UMTS protocol architecture: RLC (Radio Link Control), TCP (Transmission Control Protocol) and MAC-hs (Medium Access Control-high speed). A study of new features of the UMTS ARQ mechanisms as well as possibilities of their enrichments is studied. The stacking of ARQ mechanisms represents a risk of interactions between them. We analyze some of these interactionsLes réseaux radiomobiles de 3ème generation, tel que l'UMTS (Universal Mobile Telecommunications System) ont été prévus, dès le début de leur conception, pour offrir un mode paquet aussi bien qu'un mode circuit. Pour fiabiliser les transmissions de données en mode paquet, il faut mettre en uvre des protocoles disposant de la technique ARQ (Automatic Repeat reQuest). L'objet de cette thèse est l'étude des protocoles ARQ qui peuvent être activés dans l'architecture protocolaire globale de l'UMTS. Cela nous amène à étudier les couches contenant les protocoles ou entités suivantes : RLC (Radio Link Control), TCP (Transmission Control Protocol) et MAC-hs (Medium Access Control-high speed). L'étude des nouvelles caractéristiques des protocoles ARQ de l'UMTS ainsi que la possibilité de leur enrichissement est effectuée. L'empilement des mécanismes ARQ présente des risques d'interactions dont certains sont analysés