摘要:
A decoding method applied to a convolutionally coded signal is provided. The method includes: adjusting first input information according to a first scaling factor to generate first a-priori information; b) decoding the convolutionally coded signal according to systematic information and the first a-priori information to generate first extrinsic information; c) adjusting second input information according to a second scaling factor to generate second a-priori information, wherein the second scaling factor is generated according to the first extrinsic information and the first a-priori information; and d) decoding the convolutionally coded signal according to the systematic information and the second a-priori information to generate second extrinsic information. One of step (b) and step (d) further generates a-posteriori information as a decoding result.
摘要:
Efficient methods and apparatus for tracking decision-feedback equaliser (DFE) coefficients are described. In an embodiment, updated coefficients for a feed-forward equaliser (FFE) are generated using conventional methods and then these are used, along with an averaged updated value of channel impulse response (CIR) estimate to generate updated DFE coefficients. In an embodiment, the updated DFE coefficients are generated by multiplying the updated CIR estimate (in the frequency domain) and the updated FFE coefficients (also in the frequency domain). The resultant updated DFE coefficients in the frequency domain may then be converted into the time domain before outputting to the DFE.
摘要:
A method for an adaptive equalization apparatus in a multiple-link hopping radio system includes hopping among a plurality of radio links to receive variable-length bursts of radio signals on the plurality of radio links and equalizing amplitude and phase variations of a slow channel for each radio link from a received burst on the radio link. Further, the method includes storing the estimated tap coefficients pertinent to each radio link and using the tap weights of the current burst of the radio link to reliably pre-compensate the channel amplitude and phase distortion of a next received burst on the radio link.
摘要:
A method of blind tap coefficient adaptation includes receiving a digital data signal including random digital data, equalizing a first portion of the digital data signal using a first set of predetermined tap coefficients and a second portion of the digital data signal using a second set of predetermined tap coefficients. The method includes generating a first eye diagram and a second eye diagram from a first portion and a second portion of an equalized signal, respectively. The first eye diagram is compared with the second eye diagram to determine which of the sets of predetermined tap coefficients results in a data signal having a higher signal quality. The method includes inputting to an equalizer as an initial set of tap coefficients the first set of predetermined tap coefficients or the second set of predetermined tap coefficients according to the determination.
摘要:
Methods and apparatus adapting equalizers for compensating for signal distortion of a received digital signal are disclosed. The method comprises deriving equalizer settings for a received signal, determining at least one signal parameter of said received signal; and storing the derived equalizer settings together with an indication of the signal parameter. The signal parameter could, for instance, comprise the data rate of the signal. If the signal parameter changes the equalizer is configured to use any stored settings which are appropriate for the new signal parameter. Thus, rather than start an entirely new equalizer adaptation routine every time the signal parameter changes the equalizer will use any stored settings which are appropriate for the changed parameter.
摘要:
A wireless communication device receives CDMA signals and communicates with remote base stations in site selection diversity transmit (SSDT) mode. During communications with a primary base station, communication state parameters, such as signal to interference ratio (SIR) target values and carrier frequency estimates, are maintained for other base stations of an active set of base stations. The state parameters for communications with a selected base station are available for use after selection of a new base station. In one embodiment, the communication state parameters are used for the selection of a base from the active set.
摘要:
In high-speed mobile environments, the channel is time-varying within an OFDM symbol. This time-varying characteristic will destroy the orthogonality among subcarriers. Thus, the intercarrier interference (ICI) will occur and the system performance will be degraded. An ICI mitigation method for high-speed mobile OFDM systems is proposed, which explores the special structure of the ICI channel matrix and applies the Newton's iterative matrix inversion method. With our formulation, fast Fourier transform (FFT) can be used to reduce the computational complexity. The object of canceling the ICI can be accomplished without the need of any extra circuit.
摘要:
A wireless communication device receives CDMA signals and communicates with remote base stations in site selection diversity transmit (SSDT) mode. During communications with a primary base station, communication state parameters, such as signal to interference ratio (SIR) target values and carrier frequency estimates, are maintained for other base stations of an active set of base stations. The state parameters for communications with a selected base station are available for use after selection of a new base station. In one embodiment, the communication state parameters are used for the selection of a base from the active set.
摘要:
An optical access network system having a function of correcting upstream signal waveform distortions occurring in the PON section, wherein a central office side apparatus comprises a main controller to notify each subscriber connection apparatus of a transmission grant period, an equalizer of a tap gain adaptive control type to correct waveform distortions of signals received from the subscriber connection apparatuses, an equalizer controller, and a parameter table for storing, for each subscriber connection apparatus, the initial values of tap gains to be set for the equalizer. The main controller issues a switchover request for switching the equalization characteristic to the equalizer controller each time notifying a subscriber connection apparatus of a transmission grant period, and the equalizer controller retrieves the initial values of the tap gains for the subscriber connection apparatus from the parameter table in response to the switchover request, and sets these values to the equalizer.
摘要:
A wireless communication device receives CDMA signals and communicates with remote base stations in site selection diversity transmit (SSDT) mode. During communications with a primary base station, communication state parameters, such as signal to interference ratio (SIR) target values and carrier frequency estimates, are maintained for other base stations of an active set of base stations. The state parameters for communications with a selected base station are available for use after selection of a new base station. In one embodiment, the communication state parameters are used for the selection of a base from the active set.