In this work we consider nano-scale communication using bacterial popula- tions as transceivers. We demonstrate using a microfluidic test-bed and a population of genetically engineered Escherichia coli bacteria serving as the communication re- ceiver that a simple modulation like on-off keying (OOK) is indeed achievable, but suffers from very poor data-rates. We explore an alternative communication strategy called time elapse communication (TEC) that uses the time period between signals to encode information. We identify the severe limitations of TEC under practical non-zero error conditions in the target environment, and propose an advanced communication strategy called smart time elapse communication (TEC-SMART) that achieves over a 10x improvement in data-rate over OOK.

Passive ultra-high frequency (UHF) radio frequency identification (RFID) systems have gained immense popularity in recent years for their wide-scale industrial applications in inventory tracking and management. In this study, we explore the potential of passive RFID systems for indoor localization by developing a grid-based experimental framework using two standard and easily measurable performance metrics: received signal strength indicator (RSSI) and tag read count (TRC). We create scenarios imitating real life challenges such as placing metal objects and other RFID tags in two different read fields (symmetric and asymmetric) to analyze their impacts on location accuracy. We study the prediction potential of RSSI and TRC both independently and collaboratively. In the end, we demonstrate that both signal metrics can be used for localization with sufficient accuracy whereas the best performance is obtained when both metrics are used together for prediction on an artificial neural network especially for more challenging scenarios. Experimental results show an average error of as low as 0.286 (where consecutive grid distance is defined as unity) which satisfies the grid-based localization benchmark of less than 0.5.

Despite the fact ultra-wideband (UWB) technology has been around for over 30 years, there is a newfound excitement about its potential for communications. With the advantageous qualities of multipath immunity and low power spectral density, researchers are examining fundamental questions about UWB communication systems. In this work, we examine UWB communication systems paying particular attention to transmitter and receiver design. This thesis is specifically focused on a software radio transceiver design for impulse-based UWB with the ability to transmit a raw data rate of 100 Mbps yet encompasses the adaptability of a reconfigurable digital receiver. A 500 ps wide Gaussian pulse is generated at the transmitter utilizing the fast-switching characteristics of a step recovery diode. Pulse modulation is accomplished via several stages of RF switches, filters, and amplifiers on a fully designed printed circuit board specifically manufactured for this project. Critical hardware components at the receiver consist of a bank of ADCs performing parallel sampling and an FPGA employed for data processing. Using a software radio design, various modulation schemes and digital receiver topologies are accommodated along with a vast number of algorithms for acquisition, synchronization, and data demodulation methods. Verification for the design is accomplished through transmitter hardware testing and receiver design simulation. The latter includes bit error rate testing for a variety of modulation schemes and wireless channels using a pilot-based matched filter estimation technique. Ultimately, the transceiver design demonstrates the advantages and challenges of UWB technology while boasting high data rate communication capability and providing the flexibility of a research testbed. / Master of Science

This thesis explores the use of single-photon avalanche diodes (SPADs) for visible light communications (VLC). The high sensitivity of SPADs can potentially enhance the performance of VLC receivers. However, a SPAD-based system has challenges that need to be addressed before it can be considered as a viable option for VLC. The first challenge is the susceptibility of SPAD-based receivers to variations in ambient light. The high sensitivity of SPADs is advantageous for signal detection, but also makes SPADs vulnerable to variations in ambient light. In this thesis, the performance of a SPAD-based receiver is investigated under changing lighting conditions. Analytical expressions to quantify performance are derived, and an experiment is conducted to gain further understanding of system performance. It is shown that a SPAD-based receiver is highly sensitive to illumination changes when on-off keying (OOK) is employed, and that pulse-position modulation (PPM) is a preferred modulation scheme as it is more robust. The second challenge is broadcasting to SPAD-based receivers with different capabilities. A traditional broadcasting scheme is time-sharing, whereby a transmitter sends data to receivers in an alternating manner. Broadcasting to SPAD-based receivers is challenging as receivers may have diverse capabilities. In this thesis, a new multiresolution modulation scheme is proposed, which can potentially improve system performance over the traditional timesharing approach. The performance of the proposed scheme is analyzed, and a proof-of-concept experiment is performed to demonstrate its viability.

L'UWB (Ultra Wide Band) consiste à transmettre des signaux entre 3.1 et 10.6 GHz avec une puissance limitée à -41.3 dBm/MHz. Pour les communications hauts débits (100 à 500 Mbit/s) et courtes portées (1 à 10 m), les solutions de l'état de l'art reposent sur des traitements numériques complexes. Mitsubishi ITE propose une solution alternative multi-bandes (MB) impulsionnelle basée sur un récepteur non-cohérent. La démodulation OOK est effectuée par une détection d'énergie originale avec un seuillage adapté dynamiquement suivant les conditions de propagation. La parallélisation complète de ce système MB-OOK permet à la fois d'éviter les interférences inter-symboles et de récupérer la quasi totalité de l'énergie disponible. En outre, l'approche impulsionnelle limite les évanouissements du signal sur canal multi-trajets. La comparaison des systèmes MB-OOK et MB-OFDM démontre la pertinence de la solution proposée pour des applications très hauts débits, courte portée et faible consommation.