Rubem Pereira

Conflict Free Address Allocation Mechanism for Mobile Ad Hoc Networks

A mobile ad-hoc network (MANET) can be implemented anywhere where there is little or no communication infrastructure, or the existing infrastructure is inconvenient to use. A number of people with mobile devices may connect together to form one large group. Later on, they may split into smaller separate groups and partitions may merge if necessary. Network partitions and merges are potentially frequent occurrences in MANETs, hence address auto-configuration is an important requirement. In this paper we present a mechanism for address auto-configuration in MANETs, which is capable of assigning conflict-free addresses in a dynamic and distributed manner. Also we propose novel mechanisms to address MANET partition and merging.

Network constrained smoothing: enhanced multiplexing of MPEG-4 video

Interactive multimedia applications over multi-hop cell or packet-switched networks have strict bounds on delay, loss, and jitter. Much research has focused on how best to handle the networking issues related to supporting quality of service (QoS) contracts without compromising network efficiency, i.e. improving network utilisation, and reducing connection packet loss and late delivery. This paper describes our novel technique, network constrained smoothing, for smoothing video traffic into a server-side transmission schedule. Our approach combines QoS metrics about video connections together with network loading information in an algorithm that divides the schedule into equal-sized intervals of constant bit-rate. We evaluate performance by simulation and compare with an existing smoothing technique, optimal smoothing. We show the benefits of using network constrained smoothing to synchronise independent multimedia streams. The results show reductions in network loading at peak times and provide manageable information for routers about currently supported multimedia traffic.

Video-on-demand server: strategies for improving performance

Video-on-demand (VoD) is a service that has received much attention recently and the concept has become popular with computer and communication companies. Basically, VoD consists of a video server, interconnection network and user display equipment (UDE). It provides a similar service to the neighbourhood rental store. Videos or movies are distributed from the video server to users upon request through the network and users can view interactively using their UDE along with VCR-like functions (e.g. forward, rewind, pause and resume). VoD offers a convenient service since users do not have to leave their homes, which also leads to shorter response times than with todays video stores. One important aspect of any VoD is the storage scheme used, which affects the amount and type of storage required, the maximum number of concurrent video streams and the average waiting time experienced by users of the service from the moment they choose a video to the moment video playback starts. The paper reviews some well-known storage schemes, such as the phase-based method and the phase-based-with-replication method, and then proposes two new schemes that further increase the number of concurrent streams and reduce the waiting time, while reducing the total storage space required. These new schemes rely on two concepts called immediate playback RAM and sustainable playback storage. Using a case study, the new schemes are briefly compared with an existing scheme and their strengths and shortcomings are highlighted. Using some typical values, analyses are carried out that quantify the performance gain resulting from the new storage schemes.

Video Streaming: H.264 and the Internet of Things

Video data has been growing in importance over the last decade, and it is expected to exceed all other forms of networked data in for some time. This is also the case for the specific scenario of mobile data, where more than 60% of traffic globally will be video data. As the future Internet will encompass traffic from the Internet of Things, including low power personal devices in low quality media networks, any real time video data with source or destination in such a network will need to be encoded accordingly. In this paper we consider a few encoding options from the H.264 standard with the aim of analysing their suitability for encoding IoT related video data. We discuss the relative benefits of single layer (non-scalable) and scalable video encoders and make recommendations based on the limited capabilities of the IoT devices and transmission channels.

An effective bandwidth model for deterministic QoS guarantees of VBR traffic

Modern high speed integrated services networks have to support applications with diverse traffic characteristics and performance requirements. One of the most interesting approaches to integrate the different types of traffic is the theory of effective bandwidth. The effective bandwidth of a time varying source is the minimum amount of bandwidth required to satisfy its QoS. In this paper, we present a new deterministic traffic model that is based upon the effective bandwidth notion. The model is derived from a worst-case analysis of the traffic on a single-node basis. It uses a simple method to evaluate the minimum resources needed to guarantee the deterministic QoS requirements of a connection. The model is thoroughly analyzed and compared to other deterministic models available on literature. It achieves accuracy, simplicity of traffic characterization and of admission tests. Moreover, it simplifies the pricing process.

Cell-by-Cell Round Robin Service Discipline for ATM Networks

Multimedia applications generate network traffic that requires stringent per-connection performance guarantees, in terms of throughput, delay, jitter and packet loss. To guarantee such performance requirements, the network must maintain two levels of control: connection admission control (CAC) at the connection level and service discipline at the packet level. In this paper we present a new service discipline for statistical, deterministic and best-effort services in ATM networks. This discipline, the Cell-by-Cell Round Robin (CRR), uses the round robin idea to provide fairness among the different users and isolation between them. We show that by guaranteeing a minimum service rate for a connection, its end-to-end delay can be bounded and greatly reduced. Moreover, fixed resources are needed at all nodes in the path from source to destination. This discipline achieves flexibility in supporting different QoS requirements, and provides a policing mechanism for misbehaving users and facilitates the pricing process.

Resource allocation scheme for deterministic services of video streams

MPEG compressed video is a very important traffic type in integrated service digital networks. However, it is difficult to transmit delay and loss sensitive MPEG traffic efficiently because of its variable bit rate and bursty nature. We introduce a new scheme for allocating resources in ATM networks, for the class of MPEG applications (e.g. medical services) with the most stringent quality of service requirements. The allocation scheme is carried our through two steps. First, calculating the required resources on a per-connection basis. Second a scheduling discipline for the UNI nodes is suggested. The remaining nodes use the simple FIFO discipline. The suggested scheme leads to a reduction of bandwidth requirements. Moreover it provides a policing mechanism for misbehaving users.

Comparison Data Traffic Scheduling Techniques for Classifying QoS over 5G Mobile Networks

Enhancing Quality of Service (QoS) in mobilenetworks is the key aim for mobile operators. Mobile networkstransport several forms of data traffic for real-time applications(i.e., video monitoring). These applications need to get theadvantage of QoS adaptation. Numerous scheduling techniquesare utilized at the router to assure the QoS of the mobilenetworks. Upcoming 5G mobile networks will be launched, hence, Human-Type-Communication (HTC) and Machine-to-Machine (M2M) data traffic are expected to increasedramatically over mobile networks, which results in growing thecapacity and raising high data rates. These networks areexpected to face challenges in cases of Radio Access Network(RAN) overload and congestion due to the massive smart devicesdata traffic with various QoS requirements. This paper presentsa comparison for data traffic scheduling techniques, which arePriority Queuing (PQ), First-In-First-Out (FIFO) and WeightedFair Queuing (WFQ). We consider to select a suitable data trafficscheduling technique in terms of QoS provisioning and helping5G network, also we propose models and algorithms forefficiently utilized the smallest unit of a RAN in a relay node byaggregating and slicing the data traffic of several M2M devices.

SMART: An Application Framework for Real Time Big Data Analysis on Heterogeneous Cloud Environments

The amount of data that human activities generate poses a challenge to current computer systems. Big data processing techniques are evolving to address this challenge, with analysis increasingly being performed using cloud-based systems. Emerging services, however, require additional enhancements in order to ensure their applicability to highly dynamic and heterogeneous environments and facilitate their use by Small & Medium-sized Enterprises (SMEs). Observing this landscape in emerging computing system development, this work presents Small & Medium-sized Enterprise Data Analytic in Real Time (SMART) for addressing some of the issues in providing compute service solutions for SMEs. SMART offers a framework for efficient development of Big Data analysis services suitable to small and medium-sized organizations, considering very heterogeneous data sources, from wireless sensor networks to data warehouses, focusing on service composability for a number of domains. This paper presents the basis of this proposal and preliminary results on exploring application deployment on hybrid infrastructure.

Protocol Specification for Conflict Free MANET Address Allocation Mechanisms

A mobile ad-hoc network (MANET) is a group of mobile hosts communicating with each other via wireless links without infrastructure. Dynamic and distributed network operations are desirable for deploying MANETs due to host mobility. Many schemes have been proposed for address generation and configuration but these are without their problems. In this paper we evaluate the mechanisms of our conflict free address configuration protocol in comparison to other existing MANET auto configuration protocols. Also, we present the main distributed algorithm for new host address configuration and MANETs merging. Finally, we evaluate the protocol to demonstrate the applicability of the approach.