&ldquo;IIT Jodhpur is committed to impart quality education to facilitate the creation of qualified, competent and responsible human resources to meet the emerging technological challenges of the world. It is working towards creating an equitable learning platform that is positive, accessible and effective in the face of the modern societal and scientific advancements.

Flexibility in curriculum, in all its academic programs, encompassing elements of teaching, research, creativity, innovation and entrepreneurship is the most unique feature of IIT Jodhpur. The Department of Science and Technology (DST), under the National Mission on Cyber Physical Systems, has identified IIT Jodhpur as a Technology &amp; Innovation Hub in the area of Augmented Reality and Virtual Reality. The institute has also been nominated as the coordinator for the Jodhpur City and Knowledge Cluster by the Office of Principal Scientific Adviser, Government of India.

The sprawling 852-acre IIT Jodhpur campus is a majestic tribute to the deep-rooted diverse cultural heritage of the region. The campus is an architectural masterpiece, which is slated to become an international exemplar of sustainability with net-zero energy, and advanced water and waste management strategies.&rdquo;

IIT Jodhpur

In this paper, we consider a two-tier downlink scenario, where femtocell users are interested in receiving both macrocell and femtocell information simultaneously at a single frequency (joint two-tier downlink reception). Unlike in conventional handsets, which use orthogonal schemes for accommodating two-tier downlink reception, we propose two non-orthogonal schemes based on precoding-aided spatial modulation (PSM) for handling cross-tier downlink interference. In both the proposed schemes, the femtocell information is conveyed as an active antenna index at the user (spatial symbol), while the macrocell information is conveyed as a phase shift keyed (PSK) symbol on the activated antenna. Appropriate precoders are designed at femtocell base station (FBS) and macrocell base station (MBS) to manage the cross-tier interference. We derive average transmit powers at the MBS and all FBSs for both the schemes. We also optimize the transmit powers of both the schemes at a given target signal-to-noise ratio (SNR). Further, we exploit the existing cross-tier interference as a source of artificial interference for enhancing the physical layer security of femtocell users. We derive secrecy rates of the proposed schemes, and corroborate the analytical expressions derived throughout the paper with simulation results. © 2002-2012 IEEE.

Department of Electrical Engineering

World University root node

IEEE Transactions on Wireless Communications

Precoding-Aided Spatial Modulation Assisted Joint Two-Tier Downlink Reception

In this letter, we propose a generalized precoding-aided secure time-domain index modulation (PSTD-IM) scheme for enhancing the rate and secrecy of the system. Unlike in the conventional time-domain index modulation (TD-IM), where a single (or a set of) Nyquist pulse is activated over multiple symbol periods at the transmitter, in this letter, the pulse (or the set of pulses) is activated at the legitimate receiver, thereby securing the information transfer. In addition, we project artificial noise (AN) onto the null space of the legitimate user and degrade the signal-to-noise-ratio (SNR) at the eavesdropper. In fact, we propose the above-discussed generalized PSTD-IM for a multi-user downlink scenario, where each user is expected to receive an independent TD-IM symbol. We analyze the secrecy rate and derive a closed-form expression for an upper bound on the average bit error rate (ABER) of the proposed scheme. Further, we show that the proposed scheme achieves transmit diversity as opposed to the existing spatial modulation schemes. © 1997-2012 IEEE.

IEEE Communications Letters

Precoding-Aided Secure Time-Domain Index Modulation

Application of Internet of Things (IoT) in health, defense, banking, and other confidential information transfer urges the need for secure IoT. As most of the IoT devices are resource-limited (antennas, bandwidth, energy), securing the information transfer has always been a challenge. Looking at a solution for enhancing the security of single antenna, single carrier, energy efficient devices, we propose a novel scheme, channel-based mapping diversity. This scheme uses the inherent randomness of the wireless channel and multiple mappings available for an M -ary phase shift keying constellation in confusing an eavesdropper. When the legitimate and the eavesdropper channels are independent of each other, it is shown that a symbol error rate (SER) of \frac {(M-1)}{M} is induced at the eavesdropper. Whereas, when the channels are correlated, optimal and suboptimal strategies at source and eavesdropper are derived for their respective optimal performances. Further, a closed-form expression for a lower-bound on the SER at the eavesdropper is derived. Simulation results show that for the correlated case, as SNR at the eavesdropper increases, SER initially decreases, later saturates to a relatively high SER, hence making the job of the eavesdropper difficult in getting the legitimate data. Furthermore, the effect of the correlation is more pronounced on SER at higher levels of correlation. This indicates that for practical correlation scenarios, SER is high enough to confuse the eavesdropper. © 2014 IEEE.

IEEE Internet of Things Journal

Exploiting Mapping Diversity for Enhancing Security at Physical Layer in the Internet of Things

In this letter, we propose a novel scheme for enhancing the security of the information transfer between resource-limited devices. We select a pulse from a set of T-orthogonal pulses for shaping the data at source (S) based on legitimate channel state information (CSI). A destination (D) having the CSI, properly samples the output of the matched filter. An eavesdropper (E) having no knowledge of the legitimate CSI, may or may not sample correctly, thereby, inducing artificial intersymbol interference (ISI) at the E. We also consider a case where the S-E link is correlated with the S-D link (when E and D are closely located). We derive optimal thresholds at E, S for switching the selection of a pulse in maximizing and minimizing the achievable rate at E, respectively. We derive closed-form expressions for upper bound and lower bound on the secrecy outage probability (SOP) for the independent case. Simulation results show that unlike at D, the symbol error rate (SER) at E saturates at a high SER due to the induced ISI. © 2019 IEEE.

Channel-Aware Artificial Intersymbol Interference for Enhancing Physical Layer Security

Demand of minimal hardware requirement and low energy consumption for internet of things (IoT) has gained the importance of techniques enhancing the physical layer security. Looking at this, we propose a channel-based mapping diversity (CBMD) scheme for a source (S), destination (D) pair to increase the average bit error rate (ABER) at an eavesdropper (E). CBMD leads to an ABER of 0.5 at E when the channels between S - D and S - E are independent. In the case where S - D and S - E are correlated (due to the proximity of E at D), we derive an optimal strategy at E which leads to the best performance at E. We also derive an optimal strategy at S, assuming E uses its optimal strategy, thereby, considering the worst case scenario. A sub-optimal strategy is also proposed at S which does not require any statistical information about the link S - E and hence, has low implementation complexity. We analyze the variation of ABER at E with the signal to noise ratio (SNR) and the channel correlation coefficient. Our simulation results demonstrate that CBMD indeed leads to significant performance degradation at E even at moderate channel correlation for a properly chosen strategy. © 2017 IEEE.