Cross-layer design for power efficiency and QoS provisioning in multi-hop wireless networks

In recent years, it has become common consensus that independent consideration of communication layers often turns out to be inadequate in terms of providing the desired quality of service (QoS) and power efficiency in wireless networks. The need for a synergistic, cross-layer design framework has already been identified. In that respect, our work constitutes an important step towards a better understanding of the cross-layer paradigm by simultaneously targeting both the power efficiency and the end-to-end QoS in multi-hop wireless networks. More specifically, we address the joint problem of power control and scheduling with the objective of minimizing the total transmit power subject to the end-to-end bandwidth guarantees and the bit error rate constraints of each communication session. After identifying the inherent difficulty of the problem, we propose two classes of heuristic algorithms that rely on graph theory principles as well as on derived metrics such as effective interference. The first heuristic follows a top-down design strategy by solving the schedule feasibility problem as the initial step and then targeting the total power efficiency. On the other hand, the second heuristic follows a bottom-up approach that schedules one wireless link at a time by greedily filling up the available time slots. The simulation results reveal valuable insights about the performance of each strategy. The top-down design strategy turns out to address power efficiency issues better, whereas the bottom-up design strategy with a properly selected cost function for link scheduling shows better performance in finding a feasible solution, namely one that satisfies both the QoS and the transmit power constraints. Our results also illustrate the impact of routing decisions on the feasibility and the power efficiency of multi-hop wireless networks through employing different routing criteria in the experiments

A new control plane for 5G network architecture with a case study on unified handoff, mobility, and routing management

Due to copyright restrictions, the access to the full text of this article is only available via subscription.The tremendous growth in wireless Internet use is showing no signs of slowing down. Existing cellular networks are starting to be insufficient in meeting this demand, in part due to their inflexible and expensive equipment as well as complex and non-agile control plane. Software-defined networking is emerging as a natural solution for next generation cellular networks as it enables further network function virtualization opportunities and network programmability. In this article, we advocate an all-SDN network architecture with hierarchical network control capabilities to allow for different grades of performance and complexity in offering core network services and provide service differentiation for 5G systems. As a showcase of this architecture, we introduce a unified approach to mobility, handoff, and routing management and offer connectivity management as a service (CMaaS). CMaaS is offered to application developers and over-the-top service providers to provide a range of options in protecting their flows against subscriber mobility at different price levels

Siphoc: Efficient sip middleware for ad hoc networks

Abstract. Mobile Ad Hoc Networks (MANETs) offer a flexible way to connect mobile devices to build complex infrastructures. A key issue in MANETs is session set up and management since, unlike in conventional networks, there is no centralized component to provide such a service. Yet, session set up is necessary to provide any form of communication beyond unreliable, single message communication. In this paper we describe SIPHoc, a middleware infrastructure for session set up and management in MANETs. SIPHoc provides the same interface as the SIP standard but its implementation is fully decentralized. Moreover, SIP session establishment to and from the Internet is possible as soon as a single node in the MANET has Internet access. The paper presents the architecture and implementation of SIPHoc and evaluates its performance. The experiments show that SIPHoc is message efficient and provides a low dial-to-ring delay. SIPHoc allows SIP based applications to be used in MANETs without modification. In the paper, this is demonstrated by showing how SIPHoc supports VoIP conversations within a MANET and between the MANET and end-points on the Internet.

An Adaptive Time-Spread Multiple-Access Policy for Wireless Sensor Networks

Sensor networks require a simple and efficient medium access control policy achieving high system throughput with no or limited control overhead in order to increase the network lifetime by minimizing the energy consumed during transmission attempts. Time-spread multiple-access (TSMA) policies that have been proposed for ad hoc network environments, can also be employed in sensor networks, since no control overhead is introduced. However, they do not take advantage of any cross-layer information in order to exploit the idiosyncrasies of the particular sensor network environment such as the presence of typically static nodes and a common destination for the forwarded data. An adaptive probabilistic TSMA-based policy, that is proposed and analyzed in this paper, exploits these idiosyncrasies and achieves higher system throughput than the existing TSMA-based policies without any need for extra control overhead. As it is analytically shown in this paper, the proposed policy always outperforms the existing TSMA-based policies, if certain parameter values are properly set; the analysis also provides for these proper values. It is also shown that the proposed policy is characterized by a certain convergence period and that high system throughput is achieved for long convergence periods. The claims and expectations of the provided analysis are supported by simulation results presented in this paper