The delay estimation for orthogonal frequency division multiplexing automotive radars can be achieved through the use of different filters. This paper compares two of these filters, namely the matched filter and the zero forcing filter through two metrics, which are the peak to side lobe ratio and the integrated side lobe ratio estimated on their range profiles. The analysis is then extended to the minimum mean squared error filter.

The impulsive noise (IN) damages the performance of wireless communication in modern 5G scenarios such as manufacturing and automatic factories. The proposed receiver utilizes constant false alarm rate to obtain the threshold and combines with blanking to further improve the performance of the conventional blanking scheme with acceptable complexity. The simulated results show that the proposed receiver can achieve a lower bit error rate even if the probability of IN occurrence is very high and the power of the IN is much larger than that of the background noise.

Modulation design has a significant effect on the accuracy of a navigation system. Two problems exist in current modulations for Global Navigation Satellite Systems (GNSS). One is the extremely low transmission rate of navigation messages. The other is the pseudorange error caused by multipath. To solve the restrictions, a novel GNSS signal system is proposed in this paper. In the new signal system, navigation messages are modulated by Orthogonal Frequency Division Multiplexing (OFDM) modulation for high transmission rate as well as excellent anti-multipath performance and conventional ranging code is still transmitted by Phase Shift Keying-Rectangular (PSK-R) or Binary Offset Carrier (BOC) modulation for precise ranging. Both the signal components supplement each other. Simulation results show that using the proposed GNSS signal system, stable and high transmission quality along with high transmission efficiency for navigation data are achieved. Also, the anti-multipath performance is significantly improved with less computational complexity.

This paper presents a full-duplex dual-band orthogonal frequency division duplexing (OFDM) radio architecture that enables the radio transceiver to be more flexible and provides a viable radio link capacity gain. A simple but practical I/Q imbalance estimation and compensation method, based on the frequency-flat-fading behavior of the self-interference channel, is proposed. The performance of the proposed I/Q imbalance compensation method is evaluated by link level simulation conducted with Advanced Design System and Matlab. The co-simulation results show that the proposed radio transceiver could potentially increase the physical layer transmission rate by four times compared with the conventional radio link at the cost of tolerable loss of bit error rate performance. The I/Q imbalance compensation method can effectively compensate both high and low I/Q imbalance without the problem of algorithm convergence.

In the field of high data rate wireless communications, localization issues play a key role in achieving energy-efficient communication and geographic routing. time-difference of arrival (TDOA)-based localization methods present numerous advantages. In this paper, a new method of TDOA estimation is proposed. With this method, unlike conventional TDOA measurements, it is possible to perform communication and localization at the same time by using a multi-input single-output system. By transmitting ultra-wide-band orthogonal frequency-division multiplexing signals using spatial diversity, it is possible to extract TDOA from interference patterns in spectral domain. In addition, increasing the precision of localization is also studied using a multi-band approach. This whole study is made within the framework of the WiGig alliance specifications; however, it is compatible with other standards.

Retrieval of cloud parameters in weather radar benefits from polarimetric measurements. Most polarimetric radars measure the full backscatter matrix (BSM) using a few alternating polarized sounding signals. Using specially encoded orthogonal frequency division multiplexing (OFDM) signals however, the BSM can be measured in a single simultaneous transmission of two orthogonally polarized signals. Based on a set of parameters for weather radar, the properties of such a signal are explored and its merit as a useful capability is shown.

In this paper, we have analyzed the performance of correlated Nakagami-m fading channel by using the maximal-ratio-combing diversity at the receiver. A closed-form mathematical expression is derived for the average bit error rate (BER) for binary phase-shift keying (BPSK) and average symbol-error-rate (SER) for M-Quardrature amplitude modulation (M-QAM) scheme in terms of the higher transcendental function such as Appell hypergeometric function by using the well-known moment generating function (MGF)-based approach with arbitrary fading index for the orthogonal frequency division multiplexing (OFDM) communication systems. Moreover, we also derived an expression for the outage probability and the proposed numerical results are compared with the reported literature.

This article addresses the analysis and digital signal processing (DSP)-based mitigation of phase noise and sampling clock jitter in orthogonal frequency division multiplexing (OFDM) radios. In the phase noise studies, the basic direct-conversion receiver architecture case is assumed with noisy downconverting oscillator. In the sampling jitter case, on the other hand, the so-called direct-radio-frequency-sampling receiver architecture is deployed utilizing bandpass sub-sampling principle. The basis for the DSP-based impairment mitigation techniques is first formed using analytical receiver modeling with incoming OFDM waveform, where the effects of both oscillator phase noise and sampling clock jitter are mapped to certain type subcarrier cross-talk and distortion compared to ideal receiver case. Then iterative detection principles and interpolation techniques are developed to essentially estimate and cancel the subcarrier distortion. Also some related practical aspects, like channel estimation, are addressed. The performance of the proposed mitigation techniques is analyzed and verified with extensive computer simulations. In the simulations, realistic phase-locked-loop-based oscillator models are used for phase noise and sampling clock jitter. In addition, different received signal conditions like plain additive white Gaussian noise channel and extended ITU-R Vehicular A multipath channel are considered for practical purposes. Altogether the obtained results indicate that the effects of oscillator and sampling clock instabilities can be efficiently reduced using the developed signal processing techniques.

Orthogonal frequency division multiplexing (OFDM) waveforms offer strong advantages for integrated communication and radar systems. However, they exhibit inherent high-range sidelobes after matched filtering when standard communication constellation symbols are used for the coding of the carriers. Consequently, they require filtering at the receiver that can serve for sidelobe suppression in order to avoid target masking. However, unmasking is not the only concern; it is crucial to evaluate the filtering scheme both in terms of sidelobe suppression capability and in terms of output signal-to-noise ratio. This last criterion is essential when aiming at also detecting weaker reflections. In this paper the theoretical performance of the reiterated filtering technique based on linear minimum mean square error (LMMSE) is derived and compared to the matched filter. The unmasking capabilities are relevant, but also output power figures. Complex-valued filter output peaks are also evaluated and compared to the matched filter output peaks. Moreover, the performance of reiterated LMMSE is evaluated for OFDM communication-encoded radar waveforms.