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One of the proposals to increase the spectral efficiency of the DVB-S2 standard is based on time-frequency packing. This technique causes intersymbol and interchannel interferences to arise, requiring a significant growth of the number of pilots used to carry out frequency and phase synchronization. Therefore, a new pilot design will be introduced and suited optimal and suboptimal reduced-complexity...
Synchronization is one of the key technologies in frequency-hopping (FH) communication systems. Among four FH synchronization methods, synchronization-word (SW) is the most widely used but is still likely to be interfered. By combining SW with time of day (TOD), anti-reconnaissance capability is improved, but it takes relatively much more time to synchronize and cannot be used in Fast Frequency Hopping...
This paper proposes a novel approach for frame synchronization which applies Maximum Likelihood Ratio Testing (MLRT) coupled to Post Detection Integration (PDI) scheme. This approach is robust to frequency and phase offsets, meanwhile it considers base band signal over sampling without matched filtering and perfect timing. Derivation and realization diagram of this approach is presented. Numerical...
A new Kalman carrier synchronization algorithm is developed for high-order QAM modulated signals which shows fast acquisition times and good frequency tracking performances. The proposed solution relies on a decision directed extended Kalman filter combined with a lock detector which determines the status of the synchronization process, modifying consequently the filter parameters. Simulation results...
Robust, efficient and low complexity design methodologies for high speed multi-band orthogonal frequency division multiplexing ultra-wideband (MB-OFDM UWB) is presented. The proposed design is implemented in 0.13μm CMOS technology with the core area of 2.66mm × 0.94mm. Operating at 132MHz clock frequency, the estimated power consumption is 170mW.
This work presents a distributed detection system based on coupled oscillator arrays (COAs). The distributed detection is based on the synchronization phenomena. When the sensor elements detect an event they set the frequency of the oscillators to one value f1. If the sensors do not detect any event then the oscillators are set to f0. Due to the synchronization properties all the oscillator elements...
An improved data-aided (DA) frequency error detector (FED) and a frequency lock detector are proposed under large frequency offset for Digital Video Broadcasting Satellite Second Generation (DVB-S2) system. Computer simulations results show that the proposed error detector can increase the frequency acquisition range and decrease the acquisition time without complexity increase. Its closed-loop normalized...
Network-on-chip architectures partitioned into several Voltage/Frequency Islands (VFIs) have been proposed to alleviate problems related to integration, excessive energy consumption and clock distribution. The architecture is composed of synchronous switches that communicate with each other using bi-synchronous FIFOs. However, these FIFOs are not needed if adjacent switches belong to the same clock...
Based on synthesizing most sorts of phase/frequency locking mechanisims respectively shown in different conventional all digital phase-locked loop (all DPLL) systems, a novel all DPLL, which is with higher performances on wideband frequency tracking and also possesses a balance mechanisim for improving system performance on noise reduction as well as shortening time for arriving at a synchronous state,...
In infrastructure-less wireless systems network-wise time and frequency synchronization can be achieved by exchanging mutual synchronization errors among neighboring nodes. Cooperative synchronization is based on the use of distributed digital locked loops (D-DLLs), as the extension to distributed systems of the classical concept of (analog or digital) locked loops. The convergence to a synchronized...
Traditional infrared detection system has small viewing field and low scanning speed, a new all-directional IRST system with high scanning speed is designed, which quickly images the whole spherical airspace on the infrared sensors by the reflector circumrotating in pitching and azimuth with high speed. The real-time processing system for high speed input images is constructed based on the processor...
In this paper, we propose a robust STBC transmission scheme to combat the timing synchronization errors over frequency-selective multiple-access channels. First, the equivalent channel model in the presence of timing synchronization errors is derived and we find that the synchronization errors result in an equivalent channel model with larger number of correlated channel taps. Based on this correlated...
We propose a more accurate method to analyze multilevel frequency-shift-keying frequency-hopping code-division multiple-access (MFSK/FH-CDMA) wireless communication systems using ldquoone-hitrdquo FH patterns, instead of random FH patterns. By also removing the over-optimistic symbol-synchronous assumption, the new method provides a more realistic performance analysis as the MFSK modulation may result...
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