In order to cope with the increasing complexity of wireless networks, dynamic spectrum access, and varying application needs, fast and flexible reconfiguration of protocol stack is desired. Since Medium Access Control (MAC) layer plays a pivotal role in providing efficient spectrum sharing and utilization, rapid on-the-fly reconfigurability of MAC protocols is highly important. We have designed and implemented TRUMP: a Toolchain for RUntiMe Protocol realization. Based on the component-oriented design approach, TRUMP allows runtime realization, reconfiguration, and optimization of MAC layer according to the varying application requirements, spectral environmental, and network conditions. TRUMP, with a platform-independent MAC meta-language, also enables rapid MAC prototyping. In this article, we carry out a detailed performance evaluation of MAC schemes realized through TRUMP on WARP SDR platform. Our results indicate that TRUMP allows reconfiguration of MAC schemes in the order of a few microseconds, thus meeting the strict timeliness requirements of MAC processing. We also present application examples to highlight capabilities of TRUMP.

Recent years have witnessed a number of new and fairly complex MAC schemes for cognitive radios and other reconfigurable networks. These emerging MAC protocols impose increasing demands for flexibility, real-time response and a closer interaction between the MAC- and the physical layers. Different designs for Software Defined Radio (SDR) platforms have been investigated to realize these protocols. In this context, hardware acceleration and flexibility through hardware-software partitioning emerge as the major design considerations for prototyping and over-the-air evaluation. Following the hardware-software partitioning philosophy, this demonstration will show how MAC schemes can be decomposed into constituent functional components and how different MAC functionalities, when possible, are scheduled in a parallel fashion to enhance the execution efficiency and flexibility. In particular, we have enabled a dual-processor interrupt driven hardware architecture and supported a customized real-time Operating System (OS) kernel on the commercially available and widely used WARP SDR platform [1]. Moreover, we have adapted our framework for composing MAC protocols based on their elementary functionalities [2] to the dual-processor, OS-supported architecture on WARP boards. Our demonstration will highlight the benefits of parallelization and efficient scheduling of MAC processes in embedded realizations on SDR platforms in order to achieve a high degree of flexibility while satisfying the hard real-time constraints.

Various emerging applications enabled by wireless sensor networks demand new and versatile MAC algorithms. These MAC protocols should be able to adapt to varying application requirements and deployment conditions. In this paper, we present a component based scheme for enabling fast prototyping of MAC protocols using a lightweight tool chain. Our tool chain allows run-time MAC protocol reconfiguration by controlling the data path and the execution flow of the constituent components. Our approach of composing protocols based on common MAC components aims at reducing the protocol prototyping efforts. Moreover, our toolchain implemented for various sensor nodes provides a platform independent MAC meta-language which simplifies the protocol designing, testing and debugging processes. Empirical tests conducted on commercially available sensor nodes show that our approach enables run-time reconfiguration for MAC protocols with affordable memory consumption and execution overhead.

No abstract available.

A rapid reconfiguration of medium access scheme is required in order to achieve runtime performance optimization for dynamic spectrum access and fulfilling varying Quality of Service (QoS) demands. We have developed TRUMP, a toolchain which allows composing MAC solutions at runtime. In this demonstration, we will show how MAC reconfiguration can be achieved efficiently using TRUMP. Inspired by the optimum route calculation method used in car navigation systems, the compiler toolchain in TRUMP realizes an appropriate MAC solution at runtime. TRUMP allows expressing various types of constraints and options such as speed, energy consumption and packet delivery rate which leads to different MAC compositions. The live demonstration of MAC reconfiguration will be carried out on WARP SDR platform.

Cognitive radios are becoming the technological foundation for efficiently managing the scarcity of wireless spectrum, fulfilling various QoS demands and allowing different networks to coexist. Cognition and spectrum agility in MAC protocols require adaptability and close PHY-MAC interaction. Classically, MAC protocols have been implemented in hardware, which gives a limited possibility for reconfiguration and customization. Recently, software based MAC implementations have emerged although a close hardware-software co-design is typically required to keep the time critical operations in ASICs or FPGAs. We introduce a MAC development framework for enabling fast composition of MAC protocols, which are best fitted to the application requirements, communication capabilities of the radio, and current spectrum regulations and policies. We decompose MAC protocols into their basic functionalities which are perceived as building blocks and are partitioned across hardware/software. Our framework allows on-the-fly realization of the envisioned MAC protocol through wiring of these fundamental components. By exposing extended metadata and hardware functionalities for the MAC implementation through our granular components, together with the support for run-time re-configuration, spectrum agile and cognitive MAC solutions can be easily realized. In this paper, we describe the design rationale and implementation details of our framework on WARP boards. We show through experimental evaluation that the framework provides flexible means for prototyping different reconfigurable cognitive and spectrum agile MAC protocols.

In this poster, we focus on the cross-layer design of a low-power traffic aware MAC protocol and a content and context based routing protocol. We describe the cross-layering aspects of the MAC-Routing framework and present the performance results on real sensor node testbed.

Wireless Sensor Networks (WSNs) have been deployed in a wide range of applications with different sensing and communication requirements. As a consequence, various MAC solutions have been proposed suiting to different application characteristics [1]. However, MAC protocols are typically implemented in a monolithic fashion -- specific to a particular hardware platform. This hinders the possibility of code re-use across different platforms, which makes both implementation and porting cumbersome. It also imposes difficulties in protocol redesign when the application requirements change since the entire radio stack needs to be modified.

In this demonstration paper, we present a multi-radio MAC protocol and a prototype sensor node platform which supports dual frequency bands of operation. The multi-radio MAC protocol combines the advantages of both high and low frequency bands to give an energy efficient performance with high throughput and low latency in several applications. Our prototype supports spectrum agility, which is becoming important due to ever crowding spectrum. Besides demonstrating the improved performance metrics and spectrum agility support, we will also present the flexibility provided by our MAC protocol.