Survey of RF Communications and Sensing Convergence Research <s> G. RFID & ASSET TRACKING <s> A radar system can be used in conjunction with a coherent transponder as a communications system. A coherent transponder ("RF tag") received a stream of radar pulses, modifies these and transmits them back to the radar. This enables the RF tag to embed information in the radar data stream. We derive capacity formulas for this radar channel and then calculate these capacities for a specific SAR radar system and the RF tag configuration. We characterize the dependence of capacity on pulse repetition frequency, standoff range, and resolution. <s> BIB001 </s> Survey of RF Communications and Sensing Convergence Research <s> G. RFID & ASSET TRACKING <s> Radio frequency identification (RFID) offers tantalizing benefits for supply chain management, inventory control, and many other applications. Only recently, however, has the convergence of lower cost and increased capabilities made businesses take a hard look at what RFID can do for them. This article offers an RFID tutorial that answers the following questions: i) what is RFID, and how does it work? ii) What are some applications of RFID? iii) What are some challenges and problems in RFID technology and implementation? iv) How have some organizations implemented RFID?. <s> BIB002 </s> Survey of RF Communications and Sensing Convergence Research <s> G. RFID & ASSET TRACKING <s> In this letter, we present a graphical method based on Green's analysis of scattering antennas to optimize the load impedances for achieving maximum modulated radar cross-section (RCS) of backscattering radio-frequency identification (RFID) tags. A planar tag antenna specifically designed for working in the ultra-high-frequency band is used to experimentally validate the method. The measured RCS of the loaded tag antenna shows acceptable agreement with the theory and simulated results. This method is especially valuable to the design of semipassive RFID tags when the communication range is solely determined by the backscattering modulation efficiency of tags. <s> BIB003 </s> Survey of RF Communications and Sensing Convergence Research <s> G. RFID & ASSET TRACKING <s> The widespread deployment of RFID technology and EPCglobal compliant devices paved the way for research activities on unconventional uses of RFID, beyond the mere identification of people and goods. Focus of this paper is on a recent proposal of passive RFID tags exploitation, in particular their data storage capacity, as a new “virtual” communication channel to exchange data within piconets of RFID readers. Although earlier researches already demonstrated the great potential of this paradigm, still an analytical model for the channel performance evaluation is lacking. The model we propose in this paper, to evaluate goodput and delay over the RFID channel, considers aspects like collisions and tag memory management problems. The trustworthiness of the obtained analytical results is also validated through a simulative campaign. The study definitely helps in (i) defining data transfer rates as a function of number of readers and storage capacity of available tags, and (ii) finding the number of readers that can be served while satisfying goodput and traffic delay constraints. <s> BIB004 </s> Survey of RF Communications and Sensing Convergence Research <s> G. RFID & ASSET TRACKING <s> Nowadays, passive and semi-passive wireless devices are increasing their appeal, particularly in the new scenario of the Internet of Things, thanks to their low complexity and low energy consumption. In this context, radio-frequency identification (RFID) and radar sensor networks (RSNs) are rising interest when the localization of (semi-)passive tags (without active transmitters) and moving passive objects is required. In this paper, we propose a novel network architecture capable of jointly localizing (semi-)passive tags and moving passive objects through the analysis of their backscattered response. The reciprocal interference in objects/tags localization arising from the signal variations caused by objects' and tags' movement is characterized. We present an analytical derivation, based on the Cramer-Rao bound, providing the theoretical localization accuracy of tags and passive objects. The proposed approach represents a fundamental design tool providing insights on how system parameters (power and signal format), network topology, interference, and network configuration (monostatic or multistatic) affect the localization performance. <s> BIB005
Near field sensing technologies like radio-frequency identification (RFID) currently integrate remote sensing and data transfer to some extent. Communications is already the core functionality of RFID technology, as tags communicate back identification, health, and status information BIB002 . In addition, RFID networks have been modeled as a virtual communications capacity problem BIB004 . RFID technology has also been researched for radar detection BIB003 and localization BIB005 . Far field RFID-like radar systems have also been investigated as a joint radar-communications solution with a cooperative target BIB001 . Given that a typical RFID requires external stimulus or application of RF energy to initiate the communications link, the parallels to radar naturally arise (sending RF energy to a target for a measurement), and the joint sensing-communications aspects are immediately clear.