Rendong Ying

Narrowband Interference Mitigation in DS-UWB Systems

Interference suppression is important for ultra-wideband (UWB) systems to operate over spectrum occupied by pre-existing narrowband systems. In this letter, we first extend the code-aided interference suppression technique to a direct sequence (DS) UWB system which has been proposed for narrowband interference (NBI) suppression in direct sequence spread spectrum (DSSS) systems. Then, we introduce a new type of spreading sequence, which significantly improves the NBI suppression capability of the code-aided technique. We also discuss a preamble-aided synchronization scheme for utilizing the new type of spreading sequence.

StructSLAM: Visual SLAM With Building Structure Lines

We propose a novel 6-degree-of-freedom (DoF) visual simultaneous localization and mapping (SLAM) method based on the structural regularity of man-made building environments. The idea is that we use the building structure lines as features for localization and mapping. Unlike other line features, the building structure lines encode the global orientation information that constrains the heading of the camera over time, eliminating the accumulated orientation errors and reducing the position drift in consequence. We extend the standard extended Kalman filter visual SLAM method to adopt the building structure lines with a novel parameterization method that represents the structure lines in dominant directions. Experiments have been conducted in both synthetic and real-world scenes. The results show that our method performs remarkably better than the existing methods in terms of position error and orientation error. In the test of indoor scenes of the public RAWSEEDS data sets, with the aid of a wheel odometer, our method produces bounded position errors about 0.79 m along a 967-m path although no loop-closing algorithm is applied.

Anti-jamming filtering in the autocorrelation domain

An anti-jamming filtering technique is presented that it fully eliminates the jamming (or noncooperative) signal and its performance is noise-independent. This technique uses multiple receivers; a filtering process explores the nonoverlapping properties of the signals in the autocorrelation domain; and a matching of the input and the output statistics. A limited simulation study supports the theory.

Distributed Compressed Sensing off the Grid

This letter investigates the joint recovery of a frequency-sparse signal ensemble sharing a common frequency-sparse component from the collection of their compressed measurements. Unlike conventional arts in compressed sensing, the frequencies follow an off-the-grid formulation and are continuously valued in [0, 1]. As an extension of atomic norm, the concatenated atomic norm minimization approach is proposed to handle the exact recovery of signals, which is reformulated as a computationally tractable semidefinite program. The optimality of the proposed approach is characterized using a dual certificate. Numerical experiments are performed to illustrate the effectiveness of the proposed approach and its advantage over separate recovery.

Interference-Blocking Algorithm for OFDM Systems: Insensitive to Time and Frequency Synchronization Error

A covariance matrix based anti-interference algorithm is proposed for SIMO OFDM systems. This algorithm constructs the interference-blocking filter without the information of the inferences. This algorithm is insensitive to the time synchronization error and to the carrier frequency synchronization error. Therefore, it is especially useful for the case when interferences are strong and unknown, such as the case in the unlicensed spectrum.

Off-grid direction of arrival estimation based on joint spatial sparsity for distributed sparse linear arrays.

In the design phase of sensor arrays during array signal processing, the estimation performance and system cost are largely determined by array aperture size. In this article, we address the problem of joint direction-of-arrival (DOA) estimation with distributed sparse linear arrays (SLAs) and propose an off-grid synchronous approach based on distributed compressed sensing to obtain larger array aperture. We focus on the complex source distribution in the practical applications and classify the sources into common and innovation parts according to whether a signal of source can impinge on all the SLAs or a specific one. For each SLA, we construct a corresponding virtual uniform linear array (ULA) to create the relationship of random linear map between the signals respectively observed by these two arrays. The signal ensembles including the common/innovation sources for different SLAs are abstracted as a joint spatial sparsity model. And we use the minimization of concatenated atomic norm via semidefinite programming to solve the problem of joint DOA estimation. Joint calculation of the signals observed by all the SLAs exploits their redundancy caused by the common sources and decreases the requirement of array size. The numerical results illustrate the advantages of the proposed approach.

Next-generation consumer audio application specific embedded processor

For next-generation audio applications, the dominant trends are much higher sample rate, larger word length and more audio channels for playback audio data. Traditional DSPs or embedded processors are inefficient for such kinds of applications because of their non-specific or limited computing capabilities as well as the on-chip memory architectures. In this paper, an embedded audio processor aiming at next-generation audio applications has been proposed. The audio specific instruction set architecture is based on the analysis of the requirements for next-generation audio processing. Besides, a novel tightly coupled audio memory has been proposed to support extremely high audio data throughputs and flexible audio data transfers with main memories. To evaluate the performance of the proposed audio processor, a set of benchmarks have been used based on the analysis of next-generation audio applications. The implementation and evaluation results lead to the conclusion that the proposed audio processor is of outstanding efficiency and cost-effectiveness for next-generation audio applications.

TAB barrier: Hybrid barrier synchronization for NoC-based processors

As one of the mostly used synchronization schemes in parallel programming on multi-core processors, barrier synchronization has been extensively studied in former research works. In conventional master-slave barrier or tree barrier, usually one centric core is selected to collect barrier arriving messages and to broadcast barrier releasing messages. Unfortunately the barrier core sometimes is deviated from the center location and may lead to worse synchronization efficiency. We propose a hybrid tree-based all-to-all (TAB) barrier for NoC-based many-core processors to relieve performance degradation caused by the off-centered barrier core. Performance of TAB barrier is compared to canonical algorithms and former solution, and almost 20% time is saved during off-centered scenarios with marginal area and power overhead.

Covariance-Based Interference Blocking Algorithm for SIMO OFDM System

A covariance-based algorithm is proposed to find the interference blocking filter for single-input multiple-output orthogonal frequency division multiplexing (SIMO OFDM) systems. The algorithm uses only the auto-covariance matrix of the received signal. It does not require precise carrier synchronization and time synchronization, so it is applicable to an environment with uncooperative high power interferences

Decision feedback for autocorrelation matching anti-jamming filter

A decision feedback structure is presented to completely eliminate the jamming in communication system. This technique embeds specific autocorrelation information into the sending signal; in the receiver, an anti-jamming filter is constructed to block the jamming by matching the statistics of the filter output with reference autocorrelation function and the decision feedback. This data length required by this algorithm is much smaller than that of original autocorrelation matching algorithm. Simulation shows the reduction in residual jamming power and an improvement of SIR compare to original autocorrelation matching algorithm with same data length.