The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
We propose and demonstrate signal encryption schemes using digital chaos for orthogonal frequency division multiplexing (OFDM) signals, where discrete Fourier transform (DFT) and Walsh-Hadamard transform (WHT) are applied as chaotic precoder for peak-to-average power ratio (PAPR) reduction. The physical-layer security during transmission is enhanced, where a huge key space is created by digital chaos...
A novel encryption scheme using chaotic Zadoff-Chu matrix transform (ZCMT) precoding is proposed to improve both of the data security and performances in orthogonal frequency-division multiplexing (OFDM) transmission, where the security is significantly enhanced with a huge key space of ∼10400 provided by hyper digital chaos. The chaotic ZCMT matrix is generated with the reconfigurable parameters...
This paper proposes a novel encryption scheme for digital image during transmission, in both frequency and spatial-domain using hyper digital chaos. In frequency-domain, both of the magnitude and phase spectra of the image are encrypted, in which a huge key space is created due to hyper digital chaos. After that, additional spatial-domain encryption is implemented for security enhancement. It is proved...
We propose and analyze a novel physical layer security scheme with the capability of resisting the chosen plaintext attacks in OFDM data transmission. The proposed security scheme consists of a multiple-fold data encryption based on hyper digital chaos, which provides a huge key space. The first chaotic encryption is applied in the chaotic OFDM subcarrier allocation scrambling, both in time and frequency...
Fiber optical network offers higher data rate and larger capacity transmission, however the security issues are becoming a big concern. Digital chaos is capable of providing a huge key space for data encryption in physical layer, to enhance network security during high-speed data transmission. We will review the recent progress on security enhancement via the implementation of digital chaos for high-speed...
There is a large amount of information within every group of the received GPS positioning information, Users only need to extract and translate the useful information for them, this can be achieved by computer programs. The GPS information extraction follows the NMEA0183 standard, this paper writes a simple MFC dialog-based program based on the serial communications and GPS communication protocols...
We propose a novel security scheme to encrypt OFDM signal transmission by introducing the electro-optic chaos in optical physical layer. The transmission performance of OFDM signals is numerically evaluated with respect to the signal-noise ratio (SNR) of the chaotic channel, to guarantee both of the robust security and high quality transmission. The optimized key parameters such as the chaotic masking...
We propose and demonstrate physical layer security schemes via implementation of chaotic signal scrambling such as partial transmit sequence (PTS) and selected mapping (SLM) techniques in orthogonal frequency-division multiplexing passive optical network (OFDM-PON). The digital chaotic sequences are employed in PTS/SLM schemes to encrypt the OFDM data, which provides a huge key space to enhance the...
We propose a model to analyze the frequency chirp of directly modulated distributed Bragg reflector (DBR) laser by evaluating the carrier dynamics in DBR. Due to the opposite sign of chirp in the gain and phase sections, the chirp compensation is achieved by injecting simultaneously injecting the data signals into both of the phase and gain sections in DBR laser. The simulation shows that, the overall...
We propose a detailed frequency-domain model of the all-optical turbo-switch incorporating two cascaded semiconductor optical amplifiers (SOAs) with a broad band-pass optical filter in between the SOAs. The frequency-domain SOA model has taken the spatial inhomogeneity of the saturated SOA gain associated with the pump optical field into consideration for the first time. The simulations based on the...
A data-aided equalizer is proposed and demonstrated to compensate the amplitude and phase fluctuations in direct-detection optical OFDM. Significant improvement in error vector magnitude is achieved, using time-domain averaging on amplitude and phase independently.
All-optical turbo-switches based on semiconductor optical amplifiers (SOAs) effectively increase the switching speed via shortening the overall recovery time of the carriers. The device is numerically simulated by time-domain and frequency-domain SOA models in order to understand its operation principle and the ultimate operation speed. An integrated turbo-switch is also proposed, where a phase adjustable...
We demonstrate a symmetric 40-Gb/s TWDM-PON system using a single tunable optical filter for both downstream wavelength selection and chirp management of upstream directly modulated laser, which supports 25-km feeder fiber and 1:256 splitting ratio.
We simulated for the first time an all-optical binary pattern recognition system incorporating three SOA-based gates at 40 Gb/s. The results are in good agreement with the reported experimental demonstration.
A simple timing synchronization algorithm is proposed for IMDD optical OFDM. Accurate timing synchronization is demonstrated by simulations and experiments, with lower computation complexity.
We propose a zero-overhead amplitude and phase equalization scheme for OFDM transmission, which shows an improvement (∼3dB) of the received OFDM signal in terms of the error vector magnitude (EVM) compared with conventional pilot-aided methods.
We propose an efficiency-improved MAC protocol for OFDMA PONs that dynamically assigns control subcarriers to eliminate synchronization need and exploit statistical multiplexing gain among traffic of ONUs for high performance in delay and throughput.
We experimentally demonstrate a data-aided phase equalizer which adaptively compensates the phase noise for optical OFDM. The BER of 10−3 could be achieved by 7dBm less received optical power and therefore corroborates its superior performance.
A frequency-domain model is presented for all-optical turbo-switch incorporating two SOAs. The analysis shows the 3 dB cut-off frequency can reach up to ∼300 GHz, if a delayed interferometer is placed between the two SOAs.
Pilot pattern and pilot density are often used for channel estimation in optical/electronic orthogonal frequency division multiplexing (OFDM) systems. To enhance the performance of the channel estimation of OFDM systems, the transmission of the OFDM signals is experimentally investigated via different pilot tone arrangements for effective channel estimation. Three types of pilot patterns (comb-type,...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.