Upper-Confidence Bound for Channel Selection in LPWA Networks with Retransmissions

In this paper, we propose and evaluate different learning strategies based on Multi-Arm Bandit (MAB) algorithms. They allow Internet of Things (IoT) devices to improve their access to the network and their autonomy, while taking into account the impact of encountered radio collisions. For that end, several heuristics employing Upper-Confident Bound (UCB) algorithms are examined, to explore the contextual information provided by the number of retransmissions. Our results show that approaches based on UCB obtain a significant improvement in terms of successful transmission probabilities. Furthermore, it also reveals that a pure UCB channel access is as efficient as more sophisticated learning strategies.Comment: The source code (MATLAB or Octave) used for the simula-tions and the figures is open-sourced under the MIT License, atBitbucket.org/scee\_ietr/ucb\_smart\_retran

High-Level Design for Ultra-Fast Software Defined Radio Prototyping on Multi-Processors Heterogeneous Platforms

International audienceThe design of Software Defined Radio (SDR) equipments (terminals, base stations, etc.) is still very challenging. We propose here a design methodology for ultra-fast prototyping on heterogeneous platforms made of GPPs (General Purpose Processors), DSPs (Digital Signal Processors) and FPGAs (Field Programmable Gate Array). Lying on a component-based approach, the methodology mainly aims at automating as much as possible the design from an algorithmic validation to a multi-processing heterogeneous implementation. The proposed methodology is based on the SynDEx CAD design approach, which was originally dedicated to multi-GPPs networks. We show how this was changed so that it is made appropriate with an embedded context of DSP. The implication of FPGAs is then addressed and integrated in the design approach with very little restrictions. Apart from a manual HW/SW partitioning, all other operations may be kept automatic in a heterogeneous processing context. The targeted granularity of the components, which are to be assembled in the design flow, is roughly the same size as that of a FFT, a filter or a Viterbi decoder for instance. The re-use of third party or pre-developed IPs is a basis for this design approach. Thanks to the proposed design methodology it is possible to port "ultra" fast a radio application over several platforms. In addition, the proposed design methodology is not restricted to SDR equipment design, and can be useful for any real-time embedded heterogeneous design in a prototyping context

Decentralized Spectrum Learning for IoT Wireless Networks Collision Mitigation

This paper describes the principles and implementation results of reinforcement learning algorithms on IoT devices for radio collision mitigation in ISM unlicensed bands. Learning is here used to improve both the IoT network capability to support a larger number of objects as well as the autonomy of IoT devices. We first illustrate the efficiency of the proposed approach in a proof-of-concept based on USRP software radio platforms operating on real radio signals. It shows how collisions with other RF signals present in the ISM band are diminished for a given IoT device. Then we describe the first implementation of learning algorithms on LoRa devices operating in a real LoRaWAN network, that we named IoTligent. The proposed solution adds neither processing overhead so that it can be ran in the IoT devices, nor network overhead so that no change is required to LoRaWAN. Real life experiments have been done in a realistic LoRa network and they show that IoTligent device battery life can be extended by a factor 2 in the scenarios we faced during our experiment

An optimal architecture for a multi-standard reconfigurable radio: A network theory re-formulation

International audienceWe provide a procedure for identifying an architecture for a multistandard reconfigurable radio that is optimal in view of cost and performance (latency) considerations. We examine the trade-off between installing complex self-contained components providing high performance at a high cost (as well as size and weight), versus invoking simpler, reusable low level modules, which reduces cost but increases system latency. In the present work, we show that the the problem of finding an optimal design for a multi-standard reconfigurable radio can be reformulated as a “network design problem”. This reformulation provides a wealth of results, algorithms, and experience already available in the scientific literature. We explain the reformulation, give a simple but realistic design example, and discuss some algorithms available in the network design literature

From a Configuration Management to a Cognitive Radio Management of SDR Systems

International audienceThis paper proposes a functional management architecture for Cognitive Radio systems. It relies on a previously defined configuration management architecture for multi-standard SDR systems, and complement it to support cognitive radio features. This paper explains the requirements of Cognitive Radio systems in terms of reconfiguration, smartness and sensing capabilities. A configuration management architecture capable of dealing with the hardware heterogeneity and a wide range of reconfiguration scenarios expected with SDR systems is presented. The management is distributed over the system and a hierarchical dependency is set on 3 layers, each having a different level of knowledge of the system and the associated hardware constraints of the elements it supervises. Then a cognitive management functional architecture is derived from the previous one, copying the 3 layers of hierarchy. The roles of the elements of each layer are discussed, as well as their respective interactions and their relationships with the elements of the configuration management architecture

An Ultra-Wide Band Umbilical Cord for Cognitive Radio Systems

This paper describes how Cognitive Radio (CR) could benefit from Software-Defined Radio (SDR) compatible Ultra-Wide Band (UWB) systems. It introduces the notion of umbilical cord that can keep a CR device connected to its surrounding world, thanks to sensing and low speed over-the-air reconfiguration (OTAR) means provided by Low-Data Rate (LDR) systems, and to fast OTAR downloading facilities based on High-Data Rate (HDR) hot spots. A particular UWB architecture supporting SDR-compatible technological constraints is proposed as candidate to realize this promising combination of capabilities