Abstract:
The present disclosure discloses a method for traffic counting, in which an address space for storing the traffic data of a user is allocated in a wireless network card. The method includes the following steps of: within a preset counting period, counting uplink traffic and downlink traffic after the wireless network card accesses the network, and updating the traffic data of the current online user stored in the address space of the wireless network card. The present disclosure also provides a method for automatically calculating a cost of surfing a network, including the following steps of: monitoring updated charging standards in real time or periodically; within a preset counting period, counting uplink traffic and downlink traffic and updating the traffic data corresponding to the current user; and within a preset charging period, calculating the current cost of surfing a network of the current day or the current month according to a charging standard for surfing the network and the traffic data of the current user. Accordingly, the present disclosure further provides a device for traffic counting and a device for automatically calculating a cost of surfing a network.
Abstract:
A method includes producing interference between a received optical OFDM signal and an optical carrier extracted from the received optical OFDM signal to provide optical coherent detection of the received optical OFDM signal. Preferably, producing the interference includes optically splitting the received optical OFDM signal into a first part that is filtered to extract the carrier from the received optical OFDM signal and a second part similar to the received optical OFDM signal.
Abstract:
Systems and methods are disclosed to process an optical signal with a pre-processing module to populate a non-linearity compensation look-up table based on a set of predetermined rules in a non-real-time off-line mode; and a transmitter applying said predetermined rules in real-time to multiple channel input data to generate a real-time symbol pattern, searching the look-up table with the real-time symbol pattern to determine a non-linearity compensation output, and modulating the optical signal with the compensation output.
Abstract:
Systems and methods for optical communication that use a transmitter/receiver. The systems and methods include receiving a modulated, encoded input stream. Channel memory is reduced using coarse digital backpropagation and other channel impairments are removed using turbo equalization. Symbols are detected in the input stream that conform to a non-uniform, polar constellation having a Gaussian source distribution to produce a stream of encoded data. The stream of encoded data is decoded with one or more low density parity check (LDPC) decoders.
Abstract:
Systems and methods to communicate securely includes communicating quantum encryption data on a first wavelength-division multiplexing passive optical network (WDM-PON); and communicating data over separate classical channels of a second WDM-PON, wherein the second WDM-PON synchronizes with the first WDM-PON while providing data communication over the classical channels.
Abstract:
In a polarization-multiplexing optical communications system, a method and system for coherent reception of polarization-multiplexed optical communications. Training and data sequences are recovered from a plurality of orthogonally polarized signals, such that training and data sequences may be used on a single channel without loss of spectral efficiency. This is accomplished by estimating a channel response for each orthogonally polarized signal based on the mean of the signal and distinguishing between a data sequence and a training sequence in each orthogonally polarized signal. Such distinguishing is accomplished according to an iterative linear minimum mean-square equalization based on the respective channel response estimate.
Abstract:
Each of a plurality of data flows is classified as having a respective data flow type, and each data flow is assigned to one of a plurality of subcarrier groups, based on the data flow's type, wherein each subcarrier group comprises a respective plurality of subcarriers. First data flows assigned to a first subcarrier group are transmitted exclusively on respective subcarriers in the first subcarrier group, and second data flows assigned to a second subcarrier group are transmitted together on all of the subcarriers in the second subcarrier group.
Abstract:
Receivers and methods are provided for polarization mode dispersion compensation in multi-level coded-modulation schemes using a BLAST algorithm and iterative polarization cancellation. A receiver includes a vertical Bell Laboratories Layered Space-Time Architecture (V-BLAST) orthogonal frequency division multiplexing (OFDM) detector configured to receive input sequences and partially cancel polarization interference with respect to the input sequences to output symbol estimates for the input sequences. The receiver further includes one or more low-density parity-check (LDPC) decoders coupled to the V-BLAST OFDM detector configured to receive channel bit reliabilities and output code words. The channel bit reliabilities are indirectly calculated from the symbol estimates. The one or more LDPC decoders iteratively provide extrinsic soft information feedback to the V-BLAST OFDM detector to compensate for the polarization interference.
Abstract:
A parallel phase locked loop (PLL) system includes a first chain of a plurality of pre-locking PLLs that operates from a free-run state to a locked state; and a second chain of a plurality of PLLs to work from the locked-state to recover signal output.
Abstract:
Methods and devices for compensating for chromatic dispersion are shown that include receiving an input data signal, applying a filter to the data signal, and outputting a CD compensated signal. Applying the filter includes convolving known filter coefficients with a plurality of delayed versions of the data signal using addition and at least one inverse sign operation or using lookup tables and combining outputs to produce a CD compensated signal.