Jongho Lee

In this paper, we propose an analog self-interference cancelation scheme for full-duplex wireless orthogonal frequency-division multiplexing (OFDM) systems. Since the delay of the echo path is presented as a phase rotation of the baseband transmit signal at each subcarrier, the proposed scheme uses the rotated baseband signals to emulate self-interference signals for analog cancelation. While the conventional analog cancelation schemes are matched only to a single frequency, the proposed scheme

noise of the FTJ in the low-resistance state (LRS) is approximately two orders of magnitude larger than that in the high-resistance state (HRS), indicating that the conduction mechanism in each state differs significantly. Furthermore, the factors determining the conduction of the FTJ in each state are revealed through a systematic investigation under various conditions, such as varying the electrical bias, temperature, and bias stress. In addition, we propose an efficient method to decrease the

Gaseous pollutants, including nitrogen oxides, pose a severe threat to ecosystems and human health; therefore, developing reliable gas-sensing systems to detect them is becoming increasingly important. Among the various options, metal-oxide-based gas sensors have attracted attention due to their capability for real-time monitoring and large response. In particular, in the field of materials science, there has been extensive research into controlling the morphological properties of metal oxides.

increase by the excess holes stored in the FG by the erase operation, the sensitivity of the sensor also increases 3.2 times. The effects of CSE on various sensing performances are explained using energy band diagrams.

The proliferation of data has facilitated global accessibility, which demands escalating amounts of power for data storage and processing purposes. In recent years, there has been a rise in research in the field of neuromorphic electronics, which draws inspiration from biological neurons and synapses. These electronics possess the ability to perform in-memory computing, which helps alleviate the limitations imposed by the 'von Neumann bottleneck' that exists between the memory and processor in t

A joint channel estimation and phase noise suppression scheme for orthogonal frequency-division multiplexing (OFDM) systems is proposed for a case where channel estimation is needed symbol by symbol. In the proposed scheme, channel estimation and phase noise suppression are performed iteratively via the expectation-maximization (EM) algorithm. The proposed algorithm mitigates the performance degradation due to phase noise effectively while providing an accurate channel estimate with comparativel

In this letter, we propose an iterative detection scheme in the presence of residual frequency offset (RFO) for orthogonal frequency-division multiplexing systems using an approximate application of the space-alternating generalized expectation-maximization (SAGE) algorithm. In the proposed scheme, the expectation step intends to divide the received signal into the desired signal and the interference signal. In the maximization step, the desired signal is used to estimate required parameters (i.

In this letter, we propose an efficient detection scheme for space-time block coded (STBC) orthogonal frequency-division multiplexing (OFDM) with insufficient cyclic prefix (CP). The proposed scheme employs successive interference cancellation (SIC) and cyclic prefix reconstruction (CPR) concepts. Simulation results present that the proposed scheme outperforms the conventional scheme for STBC OFDM systems.