Flexible Medium Access Control Research Articles

FOTA-MAC: A Novel Traffic Adaptive MAC Protocol for Wireless Body Area Networks

Recently, Wireless Body Area Networks (WBANs) have emerged as a significant breakthrough in the healthcare sector due to their immense potential to revolutionize health outcomes. This type of network is able to support a diverse range of applications with traffic rates ranging from several bits per hour up to 10 megabits per second. The challenge lies in accommodating this wide range of applications and meeting their distinct requirements using a single suitably flexible medium access control protocol. In response to this challenge, our paper proposes a novel Traffic Adaptive MAC protocol designed specifically for the regular traffic of WBANs. This innovative protocol dynamically adapts its operation based on the observed traffic, leading to significant efficiency gains compared to the standardized MAC protocols IEEE 802.15.4 and IEEE 802.15.6. Our contribution aims to address the critical need for a tailored and adaptive MAC protocol that can seamlessly handle varying traffic loads within WBANs. By incorporating our protocol, we envision enhanced communication efficiency and improved performance, unlocking new possibilities for healthcare applications and ultimately revolutionizing the healthcare industry.

Software-Defined Networking Meets Software-Defined Radio in Mobile ad hoc Networks: State of the Art and Future Directions

The aims of this survey article are to elaborate on cross-layer optimization, Software-Defined Networking (SDN) and Software-Defined Radio (SDR) as separate domains of wireless network design for which a unified view has not been adequately considered to date and present lessons learned, with a view towards the challenges associated with SDN-SDR interaction that would facilitate benefits in cross-layer optimization of mobile ad hoc networks (MANETs). We focus on MANETs because ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${i}$ </tex-math></inline-formula> ) they are still at the forefront of technology, and in some scenarios they are the only meaningful option for establishing communication; ( <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">ii</i> ) they expose the full potential and benefits of coexistence and interaction of SDN and SDR, in terms of optimizing key performance indicators. While SDN and SDR are mature technologies, their interaction and joint consideration have been largely overlooked. Current SDN approaches do not span the physical (PHY) and medium-access control (MAC) layers, but they rather concentrate on network-level routing and traffic flow optimization. As a result, PHY- and MAC-layer related parameters which notoriously affect key network performance metrics remain static or at best are adapted based on some heuristic or local approaches. On the other hand, the reach of SDR architectures is restricted to the PHY and MAC layers. We discuss the state of the art of cross-layer optimization, SDN and SDR, and current challenges associated with coexistence and interaction of SDN and SDR. Such an interaction would extend the span of SDN to PHY and MAC layers and lead to realizations of centralized approaches across all layers so as to control and optimize parameters, towards global network objectives. It would also create a bridge between centralized network control that is inherent in SDN and the distributed nature of MANETs, with the add-on features of flexible and fast PHY and MAC layer adaptation offered by SDR, for solid, autonomous and ultimately better network control implementations that span all layers, towards realizing and implementing the holy grail of real cross-layer optimization.

CLAWS: Cross-Layer Adaptable Wireless System enabling full cross-layer experimentation on real-time software-defined 802.15.4

In recent years, researchers have developed a large and growing set of protocols and algorithms to improve the throughput and capacity of wireless networks. These schemes span the physical (PHY), medium access control (MAC), and higher layers of the protocol stack. Most effective innovations however require cross-layer modifications of both PHY and higher layers. To date, the verification of those designs has been limited to simulations or small setups relying often on off-line processing of the results. MAC layer results that rely on even the tiniest modification of the PHY can only be verified under simplified networking assumptions. Similarly, novel PHY algorithms are typically only verified for a single wireless link, avoiding complex scenarios. Most importantly, there is almost no cooperation between PHY and networking communities, as the tools and testbeds they use are incompatible. In this paper, we propose a methodology for fully flexible PHY, MAC, and network layer verification that is designed to (a) reuse existing software components from PHY and network communities, (b) enable both simple- and expert-level modification and configuration of all components, (c) have real-time performance benchmarked with off-the-shelf systems, and (d) enable large networking experiments including off-the-shelf nodes for rapid experimentation, testing, and comparison. The main contribution of this paper is the introduction of an approach that enables the realization of full software-defined radio (SDR) sensor nodes, all running on a single field-programmable gate array and reusing PHY layer SDR tools and typical operating systems such as Contiki OS. Subsequently, the paper will illustrate the strengths of the proposed approach by demonstrating communication with off-the-shelf sensor nodes. This allows fair benchmarking with state-of-the-art or off-the-shelf solutions. Finally, some cross-layer improvements are proposed and compared with the baseline off-the-shelf system. This proves our claims that the proposed platform is a very useful tool for cross-layer experimentation, in that it allows full cross-layer control of the PHY and network layers, and moreover enables elegant comparison with state-of-the-art designs. This architecture is provided to the open source community ( http://claws.be/ ), in order to become a framework for validating and benchmarking wireless cross-layer innovations.

Energy efficient mechanism using flexible medium access control protocol for hybrid wireless sensor networks

Energy efficiency is a primary consideration in a wireless sensor network (WSN). This is also a major parameter when designing a medium access control (MAC) protocol for WSNs. Hierarchical clustering structure is regarded suitable for WSNs due to its good performance in energy conservation. In this work, an adequately flexible mechanism for clustering WSNs is designed, in which some creative or promotional metrics are utilized, such as cluster head selection algorithm, cluster optional reconstruction, interested data transmission, multiple path routing protocol. All these strategies were cooperated to maximize energy saving of whole system. An appropriate MAC protocol for this mechanism is proposed, by flexibly switching the status of diverse sensor nodes in different strategies. The simulation results show that the proposed MAC protocol is suitable for clustering WSNs and performs well in aspects of energy efficiency, flexibility and scalability.

Rreverse link high-speed packet data support in cdma2000 1/spl times/EV-DV: upper layer protocols

This article describes the design enhancements of the upper layers of the cdma2000/spl reg/ revision D standards [Mar. 2004] supporting high-speed wireless data on the 1/spl times/EV-DV reverse link. In revision D, the reverse link peak data rate has been increased by an order of magnitude from 153.6 kb/s to 1.8 Mb/s, and the reverse link sector throughput has been improved significantly (from about 280 kb/s to 600 kb/s). The key enabling mechanisms to achieve these enhancements include a hybrid automatic repeat request protocol, adaptive higher order modulation and coding schemes, and advanced radio resource management schemes. It is well known that the reverse link is interference limited, so the system resource of interest is reverse link interference. cdma2000 Revision D introduces a variety of flexible medium access control mechanisms to allocate appropriate reverse link resources for mobile stations with various service requirements. Moreover, cdma2000 revision D greatly enhances quality of service support for the reverse link.