Abbas Bradai

Cellular software defined networking: a framework

Todays mobile customers desire to remain connected anywhere, at any time, and using any device. This phenomenon has encouraged mobile network operators to build complex network architectures by incorporating new features and extensions, which are harder to manage and operate. In this article we propose a novel and simplified architecture for mobile networks. The proposed architecture, which we call CSDN (Cellular SDN), leverages software defined networking (SDN) and network functions virtualization (NFV). SDN abstracts the network and separates the control plane from the data plane; NFV decouples logical network functions from the underlying hardware, for dynamic resource orchestration. Furthermore, we argue that dynamic resource orchestration and optimal control need real-time context data analyses to make intelligent decisions. Thus, in the proposed architecture we exploit the capability of the mobile edge networks to gather information related to the network as well as the users. This information can be used to optimize network utilization and application performance, and to enhance the user experience. In addition, the gathered data can be shared with third party service providers, enabling the realization of innovative services.

Scheduling Wireless Virtual Networks Functions

Network function virtualization (NFV) sits firmly on the networking evolutionary path. By migrating network functions from dedicated devices to general purpose computing platforms, NFV can help reduce the cost to deploy and operate large IT infrastructures. In particular, NFV is expected to play a pivotal role in mobile networks where significant cost reductions can be obtained by dynamically deploying and scaling virtual network functions (VNFs) in the core network. However, in order to achieve its full potential, NFV needs to extend its reach also to the radio access segment. Here, mobile virtual network operators shall be allowed to request radio access VNFs with custom resource allocation solutions. Such a requirement raises several challenges in terms of performance isolation and resource provisioning. In this work, we formalize the wireless VNF placement problem in the radio access network as an integer linear programming problem and we propose a VNF placement heuristic, named wireless network embedding (WiNE), to solve the problem. Moreover, we present a proof-of-concept implementation of an NFV management and orchestration framework for enterprise WLANs. The proposed architecture builds on a programmable network fabric where pure forwarding nodes are mixed with radio and packet processing capable nodes.

Virtual network functions orchestration in wireless networks

Network Function Virtualization (NFV) is emerging as one of the most innovative concepts in the networking landscape. By migrating network functions from dedicated mid-dleboxes to general purpose computing platforms, NFV can effectively reduce the cost to deploy and to operate large networks. However, in order to achieve its full potential, NFV needs to encompass also the radio access network allowing Mobile Virtual Network Operators to deploy custom resource allocation solutions within their virtual radio nodes. Such requirement raises several challenges in terms of performance isolation and resource provisioning. In this work we formalize the Virtual Network Function (VNF) placement problem for radio access networks as an integer linear programming problem and we propose a VNF placement heuristic. Moreover, we also present a proof-of-concept implementation of an NFV management and orchestration framework for Enterprise WLANs. The proposed architecture builds upon a programmable network fabric where pure forwarding nodes are mixed with radio and packet processing nodes leveraging on general computing platforms.

ReViV: Selective Rebroadcast Mechanism for Video Streaming over VANET

Video content delivery for vehicular ad hoc networks (VANET) under dense network conditions poses non trivial issues because of the scarcity and volatility of the wireless medium. In this context, video communication is envisioned to be of high benefit for traffic management as well as for providing value-added entertainment and advertising services. In this paper, we propose a new mechanism for efficient video streaming over VANET. The proposed mechanism selects a minimum sub-set of rebroadcaster vehicles in order to reduce interferences and achieve high video quality. The vehicles are ranked based on their strategic location in the network and their capacity to reach other vehicles using a new centrality metric inspired from the Social Network Analysis (SNA), called dissemination capacity. Through simulations, we compared our mechanism with the multichannel vehicular communication standard IEEE 1609.4 and another pioneering video streaming mechanism over VANET. The performance evaluation shows that it outperforms the abovementioned mechanisms by providing higher video delivery ratio, lower end- to-end transmission delay and lower frame loss ratio in both fully and intermittently connected networks.

Dynamic anchor points selection for mobility management in Software Defined Networks

Today consumers want to stay connected to networking services anywhere and at anytime. Managing consumers׳ mobility to ensure session and service continuity in efficient and effective manner is more and more challenging due to the increasing number of mobile devices and their high mobility pattern. Different solutions have been proposed in the literature to tackle this problem. They are based on a single mobility management point, called mobility anchor. Unfortunately, most of these solutions suffer from long packets delivery delay and high overhead ratio. In this work, we propose a new mobility management called Software Defined Mobility Management (SDMM) based on the Software Defined Network (SDN) paradigm. The proposed solution is network based, where the mobility is managed by network entities. In opposite to existing approaches, the anchor point is dynamically selected for each flow by a virtual function implemented at the top of the SDN controller which has a global view of the network. The main advantages of our approach are threefold: first reducing packet delivery delay, second reducing the handover latency and third minimizing the tunneling overhead.

ViCoV: Efficient video streaming for cognitive radio VANET

Abstract One of the major challenges facing vehicular ad-hoc communication is to ensure efficient services delivery under different network conditions. In this context, video communication is envisioned by the scientific and industrial communities to be of high benefit for traffic management as well as for providing value-added entertainment and advertising services. In this paper, we propose a new protocol for efficient VIdeo streaming over COgnitive radio VANETs (ViCoV), a video streaming solution which broadcasts safety and entrainment content in both fully and intermittently connected networks under different traffic conditions. First, ViCoV selects the best available dedicated or Cognitive Radio (CR) channels to disseminate the content. Then, it carefully chooses a minimum sub-set of rebroadcaster nodes to reduce interferences and to achieve high video quality. The CR channels are selected based on their stability over the time, whereas the rebroadcaster nodes are selected based on a new centrality metric, inspired from the Social Network Analysis (SNA), called dissemination capacity. Through simulations, we compared ViCoV with the multichannel vehicular communication standard IEEE 1609.4 and two pioneering video streaming mechanisms over VANET. The performance evaluation shows that ViCoV outperforms the abovementioned mechanisms in terms of providing higher video delivery ratio, lower end-to-end transmission delay and lower frame loss ratio in both fully and intermittently connected networks.

An efficient playout smoothing mechanism for layered streaming in P2P networks

Layered video streaming in peer-to-peer (P2P) networks has drawn great interest, since it can not only accommodate large numbers of users, but also handle peer heterogeneity. However, there’s still a lack of comprehensive studies on chunk scheduling for the smooth playout of layered streams in P2P networks. In these situations, a playout smoothing mechanism can be used to ensure the uniform delivery of the layered stream. This can be achieved by reducing the quality changes that the stream undergoes when adapting to changing network conditions. This paper complements previous efforts in throughput maximization and delay minimization for P2P streaming by considering the consequences of playout smoothing on the scheduling mechanisms for stream layer acquisition. The two main problems to be considered when designing a playout smoothing mechanism for P2P streaming are the fluctuation in available bandwidth between peers and the unreliability of user-contributed resources—particularly peer churn. Since the consideration of these two factors in the selection and scheduling of stream layers is crucial to maintain smooth stream playout, the main objective of our smoothing mechanism becomes the determination of how many layers to request from which peers, and in which order. In this work, we propose a playout smoothing mechanism for layered P2P streaming. The proposed mechanism relies on a novel scheduling algorithm that enables each peer to select appropriate stream layers, along with appropriate peers to provide them. In addition to playout smoothing, the presented mechanism also makes efficient use of network resources and provides high system throughput. An evaluation of the performance of the mechanism demonstrates that the proposed mechanism provides a significant improvement in the received video quality in terms of lowering the number of layer changes and useless chunks while improving bandwidth utilization.

EMCOS: Energy-efficient Mechanism for Multimedia Streaming over Cognitive Radio Sensor Networks

One of the major challenges for multimedia transmission over multimedia WSN (MWSN) in urban environment is the scarcity of spectrum combined with high radio interference. Such environment makes it difficult to ensure high bandwidth, low delay and low packet losses required for real time multimedia streaming applications. We target a scenario of video surveillance in urban environment which not only requires efficiency of spectrum utilization, but also requires energy efficient mechanisms for the battery operated MWSN nodes. In this paper, we propose a new solution for multimedia transmission over WSNs which uses cognitive radio technology for spectrum efficiency and clustering mechanism for energy efficiency. A video streaming solution is proposed that is called “EMCOS: Energy-efficient Mechanism for Multimedia Streaming over Cognitive Radio Sensor Networks”. EMCOS ensures high quality real time multimedia transmission from one or more sources to a given sink, under different spectrum availability conditions, while efficiently using the energy of the MWSN nodes. First, EMCOS clusters the MWSN nodes into different clusters in order to ensure low energy consumption. Additionally for clustering, EMCOS not only takes into consideration the geographic positions, but it also takes into account the actual and the forecast of the channel availability in order to ensure stable clusters. Once the clusters are built, a cluster head is elected for each cluster in a way which preserves the cluster energy by considering the energy utilization of all cluster members. Further, to ensure the content delivery from the source to the sink, a routing/channel selection mechanism is proposed. The channel selection is based on PU activity forecasts to prevent frequent channel switching. Simulations show that our proposal EMCOS outperforms the two existing pioneering mechanisms called SEARCH and SCEEM. EMCOS outperforms them in terms of providing higher video quality, lower end-to-end transmission delay and lower frame loss ratio under varied spectrum conditions.

On the optimal scheduling in pull-based real-time P2P streaming systems: Layered and non-layered streaming

During the last decade, we witnessed a rapid growth in deployment of pull-based P2P streaming applications. In these applications, each node selects some other nodes as its neighbors and requests streaming data from them. This scheme allows eliminating data redundancy and recovering from data loss, but it pushes the complexity to the receiver node side. In this paper, we theoretically study the scheduling problem in pull-based P2P video streaming and we model it as an assignment problem. Then, we propose AsSched, new scheduling algorithm for layered streaming, in order to optimize the throughput and the delivery ratio of the system. In second time, we derive an optimal algorithm (NAsSched) for non layered streaming. The results of simulations show that our algorithms significantly outperform classic scheduling strategies especially in stern bandwidth constraints.

Clustering in cognitive radio for multimedia streaming over wireless Sensor networks

Streaming over multimedia WSN (MWSN) in urban environment is challenging due to many issues among which spectrum scarcity and high radio interference. Such conditions make it difficult to ensure high bandwidth, low transmission delay and low packet losses required for real time multimedia streaming applications. In this paper, we propose COMUS a COgnitive radio solution for MUltimedia streaming over wireless Sensor networks which uses both cognitive radio technology and clustering mechanism to enhance spectrum and energy efficiency. In COMUS we consider clustering the MWSN nodes into different clusters to ensure low energy consumption. Furthermore, based on the nodes geographical position and the actual and the forecasted channel availability, we aim to ensure stable clusters forming. The multimedia streaming from a particular source node to the sink node, require a physical channel selection to perform the corresponding routing task. Thus, in COMUS we propose an efficient channel selection to prevent frequent channel switching which considers the PU (Primary User) activity forecasts. Our simulation results show that COMUS outperforms the two existing pioneering mechanisms called SEARCH and SCEEM and this in terms of providing higher video quality (PSNR and frame rate), lower end-to-end transmission delay and lower frame loss ratio under varied spectrum conditions.