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In this paper, an algorithm for accurate distance estimation of a vehicle to a road side unit (RSU) in urban multipath environments is presented. The algorithm is based on spatial filtering using a uniform circular array (UCA) antenna and a cross correlation based time delay detection. The time base for the cross correlation is built using Global Navigation Satellite System (GNSS) based positioning...
The contention-based (CB) transmission is a promising solution for small data packets transmission in 5G uplink. In this paper, a Non-Orthogonal Coded Access (NOCA) scheme, called ZC-NOCA, is proposed for CB transmission in 5G uplink. For ZC-NOCA, the codes generated by Zadoff-Chu (ZC) sequences is used to spread the data bit over the Orthogonal Frequency Division Multiple (OFDM) symbols. Different...
This paper proposes a fast initial cell search method based on two-step frequency offset estimation for a small cell in Long Term Evolution (LTE) heterogeneous networks using different frequency spectra. In the proposed cell search method, a set of user equipment (UE) first estimates the frequency offset of a received primary synchronization signal (PSS) from a macrocell and computes the frequency...
This paper presents a cyclic autocorrelation function (CAF) diversity combining technique for spectrum sensing using test statistics shared among multiple receive antennas with time-averaged weights. We recently reported a weighted CAF diversity combining technique, however, the weight factor has a noise component, which negatively affects the performance. This technique reduces the noise component...
Due to the ubiquity of Orthogonal Frequency Division Multiplexing (OFDM) based communications standards such as IEEE 802.11 a/g/n and 3GPP Long Term Evolution (LTE), a growing interest has developed in techniques for reliably detecting the presence of these signals in dynamic radio systems. A popular approach for detection is to exploit the cyclostationary nature of OFDM communications signals. In...
We propose a method for channel estimation in orthogonal frequency division multiplexing (OFDM) systems with an array of receiving elements. In contrast to traditional methods, which target the equivalent sample-spaced channel taps, this method targets the physical propagation paths whose delays are not restricted to the sample-spaced grid. The path delays are estimated jointly with the path gains...
In this paper a new interference mitigation scheme with resource control is proposed, to achieve the objective of higher performance in MIMO system, using interference conditions. A generic approach for both coordinated and randomized multi-user access strategies for interference mitigation is proposed. The suggestive analytical framework develops the correlation of fading channel over the space-frequency...
Recently, OFDM modulations are being considered for both optical fiber and wireless optical communications, specially due to their efficiency to combat the inter-symbol interference. Between the modifications of the standard OFDM that meet the requirements of the incoherent OFDM optical communications such as the ones that consider intensity modulation/direct detection, the asymmetric clipping optical...
Cyclostationary feature detection for spectrum sensing incognitive radio network has significant prospect in future wirelesscommunicationsystems. This work deals with the very-large scaleintegration(VLSI) architectural transformation of such detection algorithmfor field-programmable gate-array (FPGA) prototyping andapplication-specific integrated-circuit (ASIC) design. System level designof this detection...
Multiple-input multiple-output synthetic aperture radar (MIMO-SAR) has drawn widely attention for its increased degrees of freedom. This enhanced architecture offers not only the opportunity to map wider images swaths with improved spatial resolution, but also enables novel SAR modes to resolve some of the contradicting user requirements. In this paper, the performance of ground moving target indication...
An efficient handover measurement technique is proposed for millimeter-wave (mm-wave) cellular systems with directional antenna beams. Using the beam synchronization signal (BSS) carrying the cell ID and the beam ID in a hierarchal manner, handover events (interbeam handover and intercell handover) are distinguished at the physical layer. The proposed signal metrics are shown to be effective in detecting...
In this paper, a new preamble design technique that can increase the number of cell IDs (CIDs) and beam IDs (BIDs) significantly is proposed, using a preamble sequence constructed by a combination of two Zadoff-Chu (ZC) sequences. An efficient technique for the CID and BID (CBID) detection is also described for the proposed preamble. It is shown by simulations using a simple model of an mmWave cellular...
This paper addresses the design of MSE-optimal preambles for multicarrier channel estimation under a maximum likelihood or minimum mean squared error criterion. The derived optimality condition gives insight on how to allocate the pilots that compose the preamble. While many papers show that equispaced and equipowered allocation is optimal, the generalized condition demonstrates that there exist many...
In the context of broadband Power Line Communications (PLC), this work proposes an estimation and equalization method for block-pilot OFDM systems. The proposal is based on the correlation properties of Complementary Sequences (CS), performing all the operations in the frequency domain, which allows to reduce communication errors and the overall computational effort. The performance of the method...
In this paper, we propose a PLC synchronization method based on the correlation of PLC Preamble subcarrier in DOCSIS 3.1 Downstream system. The proposed method aims to find out the starting point of PLC Preamble OFDM symbol and to present the reference point for the allocation of pilot pattern used for channel estimation. We showed the performance of the proposed method through the maximum value detection...
For M-ary spread spectrum (MSS) communication systems with orthogonal frequency division multiplexing (OFDM) technique, a simple scheme to generate lots of MSS sequences is presented on the basis of circular shift and selection operation. The number of the generated sequences is far larger than sequence length at the cost of the decreased correlation property, which is significantly important to improve...
A block sparse Bayesian learning (BSBL) based approach of narrowband interference (NBI) cancellation for cyclic prefixed orthogonal frequency division multiplexing based smart grid communications is proposed in this paper. The BSBL theory is firstly introduced to recover the practical block sparse NBI with a frequency offset compared with the sub-carriers. The block sparse representation of the NBI...
In this paper, the parameters estimation for the interference rejection combining (IRC) technique with the inter-cell interference (ICI) and narrowband interference (NBI) in single-carrier frequency-division multiple access (SC-FDMA) systems is considered. Due to the characteristics of the interferences in uplink SC-FDMA systems is quite different from that in downlink orthogonal frequency-division...
The channel estimate and carrier frequency offset (CFO) acquisition are two essential bases for multiple-inputmultiple-output (MIMO) and orthogonal frequency division multiplexing (OFDM) techniques. In high-mobility scenario, the fast time varying channel and the serious Doppler frequency shift will make the channel tracking and CFO estimation much more challenging. In this paper, the achievable limits...
Cognitive radio (CR) has received increasing attention and is considered an important solution to the spectral crowding problem. The main idea behind CR technology is to utilize the unused spectral resources which are determined to be available for secondary user by effective spectrum sensing techniques. However, CR technology significantly depends on the spectrum sensing techniques which are applied...
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