Djamal-Eddine Meddour

On the role of infrastructure sharing for mobile network operators in emerging markets

The traditional model of single ownership of all the physical network elements and network layers by mobile network operators is beginning to be challenged. This has been attributed to the rapid and complex technology migration compounded with rigorous regulatory requirements and ever increasing capital expenditures. These trends, combined together with the increasing competition, rapid commoditization of telecommunication equipments and rising separation of network and service provisioning are pushing the operators to adopt multiple strategies, with network infrastructure sharing in the core and radio access networks emerging as a more radical mechanism to substantially and sustainably improve network costs. Through infrastructure sharing, developing countries and other emerging economies can harness the technological, market and regulatory developments that have fostered affordable access to mobile and broadband services. Similarly, the network operators entering or consolidating in the emerging markets can aim for substantial savings on capital and operating expenses. The present paper aims to investigate the current technological solutions and regulatory and the technical-economical dimensions in connection with the sharing of mobile telecommunication networks in emerging countries. We analyze the estimated savings on capital and operating expenses, while assessing the technical constraints, applicability and benefits of the network sharing solutions in an emerging market context.

Adaptive Distributed Gateway Discovery in Hybrid Wireless Networks

An ever-growing demand for coverage extension, higher data-rates and improved connectivity has motivated the interconnection of mobile ad-hoc networks to fixed IP networks, to form a Hybrid Wireless Network (HWN). The convergence of ad- hoc and infrastructure network is also attractive in real-world scenarios due to its practicality and usefulness. In HWNs, gateways are generally used as an interconnection point for the integrated network. In order to improve the overall performance of HWN, an efficient gateway discovery and route maintenance scheme is indispensable. In this paper, we present a novel adaptive gateway discovery scheme called ADD (Adaptive Distributed gateway Discovery), in which the adaptation is done in a fully distributed manner. Simulation results show that the distributed adaptation capabilities of our proposed scheme facilitate outperforming the existing gateway discovery mechanisms in terms of control overhead, packet delivery and delay.

Interference-Aware Routing Metric for Improved Load Balancing in Wireless Mesh Networks

Multihop wireless mesh networks are an attractive solution for providing last-mile connectivity. However, the shared nature of the transmission medium makes it challenging to fully exploit these networks. Nodes interfere with each other, resulting in packet loss and degraded network performance. In this paper, a routing metric specifically designed for WMNs is proposed. The Interference-Aware Routing metric (IAR) uses MAC-level information to measure the share of the channel that each link is able to utilize effectively. As a result, paths are selected that exhibit the least interference. Simulations show that utilizing this metric provides significant performance improvements in terms of end-to-end delay compared to several existing metrics.

Performance study of wireless mesh networks routing metrics

Multihop wireless mesh networks are an attractive solution for providing last-mile connectivity. However, the shared nature of the transmission medium makes it challenging to fully exploit these networks. In an attempt to improve the radio resource utilization, several muting metrics have been specifically designed for wireless mesh networks. However, although some evaluations have been conducted to assess the performance of these metrics in some contrived scenarios, no overall comparison has been performed. We therefore studied the performance of the most popular routing metrics currently used in wireless mesh networks; Hop Count, Blocking Metric, Expected Tran- mission Count (ETX), Expected Transmission Tune (ETT), Modified ETX (mETX), Network Allocation Vector Count (NAVC) and Metric of Inteiference and Channel-Switching (MIC). We showed under various simulation scenarios that although all the metrics except NAVC offer the same end- to-end delay and packet loss ratio, differences can he distinguished in terms of traffic load repartition. In particular, the congestion-avoidance strategies of ETX, mETX, and MIC prevent the starvation of flows following longer paths and consequently provide a more uniform traffic repartition.

IEEE 802.11n aggregation performance study for the multicast

One of the major features proposed in the IEEE 802.11n amendment is the use of frame aggregation. Thus, two types of frame aggregations are defined: MAC Service Data Unit Aggregation (A-MSDU) and MAC Protocol Data Unit Aggregation (A-MPDU). As frame aggregation is mainly defined to increase the efficiency of the MAC layer, this feature is very needed to support multimedia traffic such as High Definition TV (HDTV). The multicast transport is another way to increase the MAC layer efficiency by transmitting the same information only once to many receivers. However, the 802.11 standard does not define a reliable multicast and consequently the 802.11n is unable to provide a reliable transport for multicast streams. The 802.11aa remains the only draft to handle the unreliability issue of the multicast, but the proposed solution is defined only for the legacy 802.11 standard and does not consider the aggregation feature of the 802.11n. In this paper we design a new extension for the 802.11aa in order to take a full advantage of the 802.11n capabilities and we provide a new analytical model to evaluate the performance of the MAC layer. We particularly study the impact of the frame aggregation type on the MAC throughput for the multicast transport. Our results show that in an ideal channel (no losses), A-MSDU slightly outperforms A-MPDU when using the data rate of 6.5Mbps and both schemes have the same performance with rates of 130 and 300 Mbps. However the use of A-MPDU aggregation becomes more efficient in a noisy channel.

Adaptive packet video streaming over P2P networks

Our concern in this paper is the real-time streaming of IP packet video. We consider the scenario where we have multiple senders that stream the same video to single receiver over Peer-to-Peer networks. We propose an adaptive scheme for video streaming over P2P network that encompasses an efficient mechanism for the selection and the maintenance of sender peers nodes. Furthermore, we perform active measurements of links between the receiver and stream senders in order to optimize the overall video quality. Finally, the evaluation conducted over ns2 simulations shows that our solution allows to efficiently utilize available network bandwidth of sending peers and allow maximizing streaming qualities at the reception peer.

SINR-Based Routing in Multi-Hop Wireless Networks to Improve VoIP Applications Support

The next generation of wireless networks is expected to support a wide range of real-time multimedia applications with stringent quality of service (QoS) requirements. In this paper, we study the performance of 802.11b wireless multi-hop networks carrying Voice over IP (VoIP) calls. We compare the performance of the standard proactive ad hoc routing protocol, OLSR, which makes use of the hop count as routing metric, with two modified versions: SP-OLSR (Strongest Path OLSR) and S2P-OLSR (Shortest Strong Path OLSR). Both of them consider the Signal to Interference and Noise Ratio (SINR) to build a reliable topology graph. The cross-layer aspect is employed to compute and push the SINR values from the physical layer to the routing protocol. We implemented the proposed protocols in the Qualnet simulator and performed extensive simulations using a proper traffic model tailored for VoIP traffic in such an environment. Obtained results indicate that the quality of VoIP applications improves significantly using SP-OLSR and S2P-OLSR compared to the standard OLSR, and that S2P-OLSR offers the same performances as SP-OLSR with a lower routing overhead cost. Index Terms— Wireless multi-hop networks, performance eval- uation, VoIP, routing metrics.

A cross layer architecture for multicast and unicast video transmission in mobile broadband networks

This paper focuses on the transport of Unicast and Multicast traffic in the mobile broadband networks. The main objective is to allow video streaming applications to adapt its parameters according to 802.16MAC layer conditions and resource availability. For unicast traffic, we propose a cross layer optimizer, named XLO, between scalable video streaming application and IEEE 802.16 MAC layer. XLO uses the existing service flow management messages exchanged between a base station (BS) and a subscriber station (SS) and make them available to the video streaming application via a specific XLO interface. We implemented the XLO in the QualNet simulator and performed extensive simulations using a personalized scalable video traffic generator, capable of streaming video with different data rates and quality levels. We also introduce an enhanced admission control function at the BS that takes into account video adaptability property. The simulation results show the effectiveness of our XLO mechanism for delivering better quality of service. For multicast traffic, we propose a new solution based on superposition coding and make use of scalable video coding in order to optimize the network resources.

A Novel Dimension of Cooperation in 4G

The Fourth Generation (4G) of wireless networks is no longer a dream; it is knocking now at the doors of our information village. 4G promises to offer a vast range and diversity of converged devices, services, and networks and to revolutionize the way we communicate. 4G would influence todays networking architecture where the inter-user communication is realized with the help of third-party communication infrastructure. In 4G, the centralized third-party controlled networking architecture can emerge into a hybrid model, where a part of user-to-user interaction would be envisaged by short/medium range wireless communication systems.

Design and Performance Evaluation of IAR: Interference-Aware Routing Metric for Wireless Mesh Networks

Multihop wireless mesh networks are an attractive solution for providing last-mile connectivity. However, the shared nature of the transmission medium makes it challenging to fully exploit these networks. In an attempt to improve the radio resource utilization, several routing metrics have been specifically designed for wireless mesh networks. However none of these routing metrics efficiently tackles interference issues. Moreover, although some evaluations have been conducted to assess the performance of these metrics in some contrived scenarios, no overall comparison has been performed. The contributions of this paper are consequently twofold. First, we propose a new routing metric, Interference-Aware Routing metric (IAR), specifically designed for WMNs. IAR uses MAC-level information to measure the share of the channel that each link is able to utilize effectively. As a result, paths that exhibit the least interference will be selected to route the data traffic. Then we evaluate the performance of IAR against some of the most popular routing metrics currently used in wireless mesh networks: Hop Count, Blocking Metric, Expected Transmission Count (ETX), Expected Transmission Time (ETT), Modified ETX (mETX), Network Allocation Vector Count (NAVC) and Metric of Interference and Channel-Switching (MIC). We show under various simulation scenarios that IAR performs the best in terms of end-to-end delay and packet loss, and provides the fairest resource utilization.