Fujitsu Corporation

Jianmin Zhou

Hui Li

Takanori Iwamatsu

Zhan Shi

Pei Chen

Gang Sun

Xin Wang

Hiroyuki Hayashi

Michiharu Nakamura

Jie Wu

Yuuta Nakaya

Donglin Wu

Zhiqi Wang

Syuusaku Suzuki

Embodiments of the present disclosure provide a multipath time delay estimation apparatus and method and a receiver. Time delay is divided into at least two subzones according to cross-correlation values of the transmission signal and the received signal, and time delay estimation is performed on each path in each subzone respectively, thereby efficiently improving resolution of the time delay estimation. And in performing time delay estimation on each path in each subzone, cross-correlation values of other subzones are set to be predefined values, so as to lower influence of strong paths of other subzones on the time delay estimation on each path in the current subzone, thereby efficiently improving accuracy of time delay estimation of weak paths.

Multipath time delay estimation apparatus and method and receiver

Embodiments of the present invention provide an optimizing apparatus and method for a pulse shaping filter and a transmitter. The apparatus is configured to determine an initial peak-to-average power ratio threshold of the pulse shaping filter, and determine an initial filter coefficient of the pulse shaping filter according to the initial peak-to-average power ratio threshold; determine a constraint condition for optimizing the pulse shaping filter according to the initial peak-to-average power ratio threshold and the initial filter coefficient of the pulse shaping filter; wherein the constraint condition comprises a threshold constraint in a filter coefficient sign domain; and adjust the initial peak-to-average power ratio threshold and the initial filter coefficient of the pulse shaping filter in a case where the constraint condition is satisfied, until a predefined condition is satisfied, so as to obtain an optimized filter coefficient of the pulse shaping filter.

Optimizing apparatus and method for a pulse shaping filter and a transmitter

A digital predistortion apparatus comprising: a nonlinear device; a memory effect compensator; a constant value characteristic acquirer; a cost function generator; and a coefficient updater is described.

Digital predistortion apparatus and method

The present disclosure provides a digital pre-distortion transmitter and a method for controlling the same, which increase the efficiency of the power amplifier and improve the linearity of the transmitter. The digital pre-distortion transmitter includes: a pre-distortion unit configured to update a pre-distortion coefficient required by pre-distortion processing, and perform the pre-distortion processing on a baseband signal; a signal process and transmit unit configured to perform signal processing on the pre-distortion-processed baseband signal and transmission thereof; and a feedback signal process unit configured to process a feedback signal of the signal transmitted by the signal process and transmit unit, so as to supply a dynamic drain voltage to a power amplifier in the signal process and transmit unit by using the processed feedback signal; and, the pre-distortion unit updates the pre-distortion coefficient by using the feedback signal processed by the feedback signal process unit.

Digital pre-distortion transmitter and method for controlling the same

Embodiments of the present invention provide a temperature compensation method and apparatus for a received signal strength indicator. The apparatus comprises a temperature sensor configured to measure a current temperature; and a digital compensation module configured to select a temperature compensation coefficient from prestored temperature compensation coefficients corresponding to a normal temperature, a low temperature and a high temperature according to the current temperature, and perform temperature compensation on output signals of the RSSI according to the selected temperature compensation coefficient. With the method and apparatus of the embodiments of the present invention, the accurate power values of the input signals of the RSSI under any temperatures can be obtained by measuring the characteristics of the RSSI under the predefined three temperatures, and using an interpolation method to compensate for the temperature characteristics of the RSSI. In comparison with the relevant art, the size of the storage is decreased and the accuracy of temperature compensation is improved.

Temperature compensation method and apparatus for received signal strength indicator

An automatic gain control device includes: a variable gain adjusting unit, for adjusting an input signal by a variable gain and outputting an adjustment result; an analog-digital converting unit, for performing analog-digital conversion on the adjustment result to obtain an analog-digital conversion result; and a gain determining unit, for determining a distribution status over a predetermined period of time of a maximum or a minimum of the analog-digital conversion result, comparing the distribution status with a first distribution condition, and if the distribution status meets the first distribution condition, then keeping the variable gain unchanged, otherwise changing the variable gain and determining newly a distribution status until the newly determined distribution status meets a second distribution condition which is at least as strict as the first distribution condition.

Automatic gain control device and method, power adjusting device and radio transmitting system

A method and apparatus for controlling update of digital pre-distortion (DPD) coefficient is provided. The apparatus is applicable to a digital power control system, wherein the apparatus comprises: an update controlling unit configured to determine a group of fully-trained DPD coefficients among a plurality of DPD coefficients; and a DPD coefficient generating unit configured to update adaptively the group of fully-trained DPD coefficients according to the result of judgment of the update controlling unit. The DPD coefficients are allowed to be updated after being judged as being able to be fully trained according to power distribution information of DPD input signals, or according to address distribution information of an LUT, or according to average power of output of an HPA; otherwise, they may not be updated, thereby efficiently preventing DPD abnormality resulted from unfull training of coefficients in being updated.

Method and apparatus for controlling update of digital pre-distortion coefficient

The embodiments of the present invention provide a predistortion device, method for predistortion and transmitter/receiver system. The predistortion device comprises a predistortion unit, and the predistortion device further comprises: a signal acquiring unit to process the output signals of a transmitting circuit to obtain distorted signals; a signal coupling unit to couple the distorted signals acquired by the signal acquiring unit to the receiving signals inputted to a receiving circuit; and a signal processing unit to decouple the output signals of the receiving circuit to acquire the distorted signals and the receiving signals. With the embodiments of the present invention, an analog receiving circuit may be reused in a half duplexing system and a full duplexing system, and the requirement on the analog receiving circuit is lowered, thereby reducing the cost.

Predistortion device, method for predistortion, and transmitter/receiver system that reuse an analog receiving circuit in a half duplexing system and a full duplexing system, and that reduce the requirement on the analog receiving circuit

This invention relates to an apparatus for and a method of controlling a predistorter, and a method of detecting power control state. The method of controlling a predistorter, which is for predistorting a signal input into a power amplifier, comprises storing predistortion coefficients used by the predistorter; acquiring indices each indicative of an output power of the power amplifier; detecting, based on the indices acquired in the acquiring, whether the power amplifier is in a state of undergoing power control; and supplying the stored predistortion coefficients to the predistorter when it is detected that the power amplifier is in the state of undergoing power control, or supplying, when it is detected that the power amplifier is not in the state of undergoing power control, to the predistorter predistortion coefficients calculated by a unit that performs predistortion coefficient adaptive updating operation.

Apparatus for and method of controlling a predistorter, and method of detecting power control state

An embodiment of the invention discloses a power amplification device and method and a method for acquiring a power adjusting coefficient. The power amplification device according to one embodiment of the invention includes: a power control module configured to perform power adjusting on an input signal; a power amplification module configured to perform power amplification on the signal subjected to the power adjusting by the power control module; and a pre-distortion module configured to compensate for nonlinear characteristic of the power amplification module; wherein, said power control module is coupled between said pre-distortion module and said power amplification module in series; alternatively, said pre-distortion module is coupled between said power control module and said power amplification module in series. With the embodiment of the invention, a transmitter can be provided with a spectrum including a low side lobe even upon startup.

Power amplification device and method for acquiring power adjusting coefficient

An adaptive digital predistortion device and method, the adaptive digital predistortion device including a predistortion unit for predistorting an input signal according to a predistortion parameter stored in a look-up table; a cost function generation unit for generating a cost function; a fixed segment point determination unit for determining a fixed segment point; and an update unit for updating parameters (u, u, k) according to the cost function to update the look-up table based on the updated parameters (u, u, k), wherein kis an updated adaptive segment point, uand uare slopes on two sides of the adaptive segment point ka; and for subsequently updating parameters (v, v) according to the cost function to update the look-up table based on the updated parameters (v, v) and the fixed segment point, wherein vand vare slopes on two sides of the fixed segment point. Therefore, the adaptive digital predistortion device according to the present invention can obtain a good performance within an acceptable convergence time by combining the adaptive segment with the fixed segment.

Adaptive digital predistortion device and method

The present invention relates to an apparatus and method of frame synchronization in broad band wireless communication systems. In an apparatus of frame synchronization in a mobile station, a time variant phase rotation compensator eliminates time variant phase rotation carried in received signals by conjugated multiplication between adjacent signal samples. Then, the processed signal is fed into a delay correlator to calculate a plurality of correlations between two successive frames. A local power calculator acquires an average power of several symbols centered on delayed correlation values. A normalizer normalizes the delayed correlation values with a local average power corresponding to the delayed correlation values. A maximum value detector selects the maximum value from normalized correlation values to trigger frame synchronizing and timing signals.

Apparatus and method of frame synchronization in broad band wireless communication systems

This invention relates to a predistorter, a predistortion method, and a predistortion system. The predistorter comprises a modulus value determining section, for determining a modulus value of an input signal; a base searching section, for searching a predetermined base lookup table in accordance with the modulus value of the input signal, so as to obtain a base lookup table value; an offset searching section, for searching a predetermined offset lookup table in accordance with the modulus value of the input signal, so as to obtain an offset lookup table value; an interpolation factor generating section, for generating an interpolation factor in accordance with the modulus value of the input signal; a multiplying section, for multiplying the offset lookup table value with the interpolation factor; and a summating section, for adding a product obtained by the multiplying section to the base lookup table value, so as to obtain a predistortion value.

Predistorter, predistortion method, and predistortion system

The present invention discloses a baseband predistorter and baseband predistortion method. The baseband predistorter comprising: an address generator for calculating an address of a phase basic lookup table and an address of an amplitude basic lookup table; a parameter determining unit for determining a phase translational amount, an amplitude translational amount, a phase curvature adjustment amount and an amplitude curvature adjustment amount; a phase translating unit for changing the address in accordance with the phase translational amount; an amplitude translating unit for changing the address in accordance with the amplitude translational amount; a phase basic lookup table searching section for determining a corresponding phase output; an amplitude basic lookup table searching section, for determining a corresponding amplitude output; a phase curvature adjusting section, for adjusting the phase output; and an amplitude curvature adjusting section, for adjusting the amplitude output.

Baseband predistortion device and method

The present invention discloses a predistortion apparatus, a predistortion system and a predistortion method. The predistorter comprises a modular value calculating section, for performing modular arithmetic on an information source input signal inputted from an information source; an orthogonal lookup table value acquiring section, for searching N stored lookup tables orthogonal to one another, finding out corresponding output of each lookup table in accordance with the modular value of the information source input signal, and acquiring N lookup table values, wherein N is an integer greater than 1; a multiplying section, for multiplying the N lookup table values acquired by the orthogonal lookup table value acquiring section with N amplitude adjustment factors to obtain N amplitude adjustment values, and multiplying the N lookup table values with N phase adjustment factors to obtain N phase adjustment values; and a summating section, for summating the N amplitude adjustment values to obtain an amplitude predistortion value, and summating the N phase adjustment values to obtain a phase predistortion value.

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Beijing, China

Jianmin Zhou