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Fixed, portable and mobile terminals use Random Access (RA) to transfer data or request more spectrally efficient dedicated resources. This paper describes a new multiple access scheme, A- SCMA, that operates with unsynchronized transmission and low power, making it particularly suitable to small machine-to-machine communications in satellite or terrestrial applications. A multicarrier version operates...
Orthogonal frequency division multiplexing (OFDM) technique, with a broad usage in recent communication technologies, provides a good performance that is mostly appropriate for target quality of service levels. Yet, it will not be effective for future requirements due to its synchronization and spectral efficiency related communication system drawbacks. To address these issues, universal filtered...
In this paper we study the problem of estimating the unknown delay(s) in a system where we receive a linear combination of several delayed copies of a known transmitted waveform. This problem arises in many applications such as timing-based localization or wireless synchronization. Since accurate delay estimation requires wideband signals, traditional systems need high-speed AD converters which poses...
Cloud radio access network (C-RAN) is a recent trend of RAN architecture positioned to help the operators to address challenges of new wireless services, such as emerging 4G and 5G mobile networks. C-RAN uses baseband processing units in a central server which connects to the radio front-ends at cell sites via the so-called fronthaul network. The fronthaul infrastructure is currently provided by CPRI...
In this work an analysis of a distributed algorithm for the optimization of signal setting on urban network is proposed. The Traffic Signal Synchronization is a traffic engineering technique of matching the green light times for a series of intersections to enable the maximum number of vehicles to pass through, thereby reducing stops and delays experienced by motorists. Synchronizing Traffic Signals...
In this work a distributed algorithm for the optimization of signal setting on urban network is proposed. The Traffic Signal Synchronization is a traffic engineering technique of matching the green light times for a series of intersections to enable the maximum number of vehicles to pass through, thereby reducing stops and delays experienced by motorists. Synchronizing Traffic Signals ensures a better...
A wavelet neural network (WNN)-based robust total-sliding-mode control scheme is developed for the synchronization of uncertain chaotic systems. The proposed control system offers a design method to drive the state trajectory to track a desired trajectory, and it is comprised of an adaptive WNN controller and a robust compensator. The adaptive WNN controller acts as the principal tracking controller,...
Internode line impedance values are essential information for achieving coordinated voltage regulation with distributed energy devices. However, in a low-voltage distribution system, these values are difficult to acquire, especially when the devices are installed in an ad hoc manner by individual users. This paper proposes a novel method for automated impedance estimation based on practically available...
For single-channel of 16QAM mixed signals, a non-data-aided (NDA) frequency offset estimation (FOE) algorithm is proposed. The frequency offset of signals after down conversion affects the phase of the signal and make the signal rotate so that the extremum of the in-phase components and the quadrature components of signals are changed. Calculation of the frequency offset by optimizing the object functions...
We consider low latency uplink communication where users transmit their signal using generalized frequency division multiplexing (GFDM) with K subcarriers and M sub-symbols. The proposed approach for synchronization exploits both training subcarriers and training subsymbols embedded in a GFDM symbol. A frequency domain training sequence (FD-TS) of length M is loaded on each training subcarrier, and...
This paper investigates a source localization problem using time difference of arrival (TDOA) measurements in the presence of non-ideal clock parameters between sensors. A joint estimation of the clock offset and of the clock skew of an imperfect clock of an asynchronous receiver under the assumption of affine clock model is proposed. To achieve synchronization among sensors, we opt for a receiver...
Clock skew measurement can be realized in one-way communication by continuously collecting timestamps from the same remote device, and then find the slope of best fit to the offset dataset. However, offsets collected in mobile network may form multi-segmented distribution due to the change of base station or network adapter. This type of distribution usually cause the existing methods fail to provide...
In order to provide more reliable state estimation addressing the problem of the bad data (BD) in the Phasor Measurement Unit (PMU)-based power systems synchronization, the paper focuses on developing a novel nonlinear estimation framework to track the voltage magnitude, phase angle, and frequency of the utility power grid. Instead of directly analyzing in abc coordinate frame, the symmetrical component...
The ultimate boundedness of a chaotic system is very important for the study of the qualitative behavior of a chaotic system. At present, explicit ultimate bound sets can be analytically obtained only for some special chaotic systems, and few results are known for hyperchaotic ones. In this paper, we investigate the ultimate boundedness for the new hyperchaotic Lorenz system by mathematical proof,...
Several space missions launched in recent years used satellite formations for which inter-satellite links (ISL) have to be developed. One of the important challenges to be solved in an ISL is time and frequency synchronization between the two satellites. In this paper we analyze the performance of three timing offset and fractional carrier frequency offset estimation techniques for orthogonal frequency-division...
In this paper, a layered preamble denoted as LP1 is proposed based on Layer Division Multiplex (LDM). The preamble is composed of two OFDM symbols. The first symbol is fixed and used for timing and frequency synchronization. The second symbol is a combination of two layers which both convey system parameters associated with system structure. Because of good cross-correlation of PN sequences with different...
In this paper, we propose a local positioning system which can provide accurate position estimation using VHF band. The proposed system has much higher accuracy than GPS system using wide bandwidth, low RF frequency. While the GPS uses time information to calculate time of arrival between the transmitter and the receiver, the local positioning system only uses time difference information of arrival...
Advances in device-to-device (D2D) ecosystems have brought on mobile applications that utilise nearby mobile devices in order to improve users' quality of experience (QoE). The interactions between the mobile devices have to be transparent to the end users and can be of many services - opportunistic networking, traffic offloading, computation offloading, cooperative streaming and P2P based k-anonymity...
Two estimation algorithms for the spreading sequence in DSSS signals are proposed. Some of previously proposed algorithms have some drawbacks such as large computational complexity, low estimation accuracy and poor accuracy by increasing the length of spreading sequence period. In this paper by using an initial estimate of chips, we can improve recursively the final decision with low computational...
Because of the wide field of view (FOV) to monitor vessel movements, satellite-based automatic identification system (S-AIS) has been promoted in recent years. However, synchronization is a tough work in S-AIS receiver because of the large Doppler shift and serious signal collision resulting from simultaneous transmission in the FOV of a satellite. In this paper, we propose a pipelined synchronization...
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