Evaluation of different signal propagation models for a mixed indoor-outdoor scenario using empirical data

In this paper, we are choosing a suitable indoor-outdoor propagation model out of the existing models by considering path loss and distance as parameters. A path loss is calculated empirically by placing emitter nodes inside a building. A receiver placed outdoors is represented by a Quadrocopter (QC) that receives beacon messages from indoor nodes. As per our analysis, the International Telecommunication Union (ITU) model, Stanford University Interim (SUI) model, COST-231 Hata model, Green-Obaidat model, Free Space model, Log-Distance Path Loss model and Electronic Communication Committee 33 (ECC-33) models are chosen and evaluated using empirical data collected in a real environment. The aim is to determine if the analytically chosen models fit our scenario by estimating the minimal standard deviation from the empirical data

Associative Search Network for RSSI-basedTarget Localization in Unknown Environments

International audienceReceived Signal Strength Indicator (RSSI) is commonly consideredand is very popular for target localization applications, since itdoes not require extra-circuitry and is always available on current devices.Unfortunately, target localizations based on RSSI are aected withmany issues, above all in indoor environments. In this paper, we focus onthe pervasive localization of target objects in an unknown environment.In order to accomplish the localization task, we implement an AssociativeSearch Network (ASN) on the robots and we deploy a real test-bedto evaluate the eectiveness of the ASN for target localization. The ASNis based on the computation of weights, to "dictate" the correct directionof movement, closer to the target. Results show that RSSI through anASN is eective to localize a target, since there is an implicit mechanismof correction, deriving from the learning approach implemented in theASN

HAMAC: High Adaptive MAC Protocol for DenseRFID reader-to-reader Networks

International audienceThis paper proposes a high adaptive contentionbasedmedium access control (HAMAC) protocol that considerablyreduces readers collision problems in a large-scale dynamic RFIDsystem. HAMAC is based only on realistic assumptions that canbe experimented and does not require any additional componentson RFID reader in order to improve the performance in terms ofthroughput, fairness and latency. The central idea of the HAMACis for the RFID reader to use a WSN-like CSMA approachand to set its initial backoff counter to the maximum valuethat allows to mitigate collision. Then, according to the networkcongestion on physical channels the reader tries to dynamicallycontrol its contention window by linear decreasing on selectedphysical channel or multiplicative decreasing after scanning allavailable physical channels. Extensive simulations are proposedto highlight the performance of HAMAC compared to literature’swork in large-scale RFID systems where both readers andtags are mobile. Simulation results show the effectiveness androbustness of the proposed anti-collision protocol in terms ofnetwork throughput, fairness, coverage and time to read all tags