36 results about "Rake reception" patented technology

A method and apparatus for determining operating modes in a receiver is described herein. A delay searcher in the receiver detects a signal image in the received signal. When the receiver is a RAKE receiver, a plurality of RAKE fingers coherently combine time-shifted versions of the received signal at different delays. Alternatively, when the receiver is a chip equalization receiver, an FIR filter coherently pre-combines the signal images in the received signal. A processor determines delays. In particular, the processor generates a first signal quality metric for a single-delay receiver mode, and generates a second signal quality metric for a multi-delay receiver mode. Based on a comparison of the first and second signal quality metrics, the processor selects the single-delay or the multi-delay receiver mode for processing the signal image.

A searcher detecting signal indicating conditions of propagation paths is detected from incoming waves of a pilot signal transmitted at the highest electric power. In a RAKE reception for one code channel, an interference replica signal functioning as an interference signal for an incoming wave of the code channel to be demodulated in one finger unit is produced from reference signals produced in the other finger units and the searcher detecting signal, an interference removal is performed for a receiving signal according to the interference replica signal, and the demodulation of the RAKE reception is performed. In the demodulation based on a plural code channel, a reference signal is produced in one of the finger units, an interference replica signal is produced from the reference signal and the searcher detecting signal, an interference removal is performed for the receiving signal according to the interference replica signal, and the demodulation based on the plural code channel is performed. Accordingly, a service of a high speed data transmission can be performed without increasing an occupied band as well as a service mainly performing a low speed data transmission.

The present invention relates to a new parallel interference cancellation (PIC) configuration where the PIC is implemented after the rake reception and multipath combining. In the invention disclosed, the regenerated interference contributions (functions of signature sequence cross-correlations) for multiuser detection (MUD) in a multipath radio channel are explicitly filtered through the estimated multipath channels, and stored. These stored quantities already contain the effect of the channel, and only need updating according to the rate of change of channel dynamics, and not the symbol period. During each symbol period, interference is computed from each interfering user to each desired user using current estimates of symbol decisions and the aforementioned interference contributions. The precomputation of the interference contributions, which are valid for a sequence of symbols, allows for extremely low complexity baseband processing in the receiver.

A wireless communication apparatus and a receiving scheme selection method are provided for improved overall system throughput. SIR measurer (106) measures the SIR of a known signal. Doppler frequency detector (108) detects the Doppler frequency from the received signal and measures the Doppler shift amount. The Doppler shift amount serves as an indicator of the moving speed of the mobile station apparatus. Interference power measurer (110) measures interference power from other cells. Known signal obtainer (104), SIR measurer (106), Doppler frequency detector (108), and interference power measurer (110) constitute a propagation environment estimator in this embodiment. Based on the SIR, Doppler shift amount, and interference power, receiving scheme selector (112) selects a receiving scheme of either RAKE reception or linear equalization.

A RAKE reception device capable of allocating an appropriate number of fingers to a channel. In this device, a selection control section (301) sets a finger (304) allocated to the channel from the channel communication state and a control signal based on this setting is output to a synchronization processing section (302) and to a selection switch (303). According to the control signal, the synchronization processing section (302) detects a path and a spread code phase in a reception signal and allocates the detected path to the finger (304) which has been set. The finger (304) which has been set de-spreads the signal of the path allocated and performs coherent detection. According to the control signal, the selection switch (303) switches the connection between the finger (304) and a maximum ratio combining section (307) so that the output from the finger (304) is output to the maximum ratio combining section (307).

A receiver informs a delay profile and CIR measured in an FDE or a Rake receiver, together with a bit error rate of a received signal that is required in a receiver, as quality information to a transmitter. In the transmitter, based on the delay profile and CIR contained in the notified quality information, a number of code division multiplex and a frame format are decided in a decision circuit such that a bit error rate of a received signal, which is necessary on the receiver side, can be obtained. In addition, a transmission selection switch selects one of a unique word insertion unit and a cyclic prefix insertion unit that create a frame format for FDE reception and a pilot insertion unit and a complex scrambling unit that create a frame format for Rake reception, and data is then transmitted.

The present invention can eliminate the multipath effect, channel interference and Doppler effect in mobile communication. The reception method includes the direct treatment of the received RF baseband signal with filter, multiplier and preset data and the direct feeding of the treated signal to the software adjudication decoder. The RAKE receiver of the present invention consists of matching filter, delay search tracker, predicting filter, smoothing filter, delay regulator, multiplier, multipath adder, filter parameter data base, S / N measuring comparator and one-out-of-three selector.

The invention relates to a method for receiving a long scrambling code of a downstream cluster service in a time division duplex communication system, which comprises the steps as follows: a base station broadcasts and transmits system data information with the long scrambling code to a target user group in the cell; user equipment estimates channel impulse responses for training sequences in the cell and in the neighboring cells according to the received system data information to obtain the channel impulse responses corresponding to each cell; the power of the channel impulse responses of each cell is estimated to obtain the power of the channel impulse responses corresponding to each cell, and the power of the channel impulse responses is sorted to determine the cells with effective receptions; and the rake reception and interference elimination, demodulation and decoding process are carried out cell by cell to the cells with effective receptions so as to obtain expected user data. Based on the method, the invention also provides a receiver-transmitter unit for realizing the method. The invention effectively overcomes the multi-cell interference, so as to improve the transmission performance of the cluster mass-sending service and the cell capacity.

A radio communication apparatus which is used in a CDMA communication system, has a plurality of fingers, and performs rake reception, includes a delay profile calculating section and a finger path allocating section. The delay profile calculating section calculates a delay profile using a reception signal. The finger path allocating section allocates path positions to the plurality of fingers on the basis of the delay profile calculated by the delay profile calculating section. A delay profile calculation cycle in the delay profile calculating section is variable. A power consumption control method is also disclosed.

To provide an apparatus which reduces the scale of a reception circuit and the power consumption as the tracking function of tracking phase jitter of the multipath propagation route. A RAKE reception apparatus includes a plurality of finger circuits for receiving signals spectrum-spread by spread codes, despreading respective reception signals retrieved by a searcher adapted for retrieving respective paths from multipath reception signals for demodulating the signals, and a RAKE combiner for combining outputs of the plural finger circuits. Each of the plural finger circuits is provided with one DLL circuit without being provided with an inner DLL circuit. The finger circuits to be tracked by the DLL circuit are switched by a changeover circuit. There is provided a control circuit for controlling the changeover circuit based on the weighting information for each finger circuit to be found by the RAKE combiner for sequentially selecting the finger circuits to be tracked by the DLL circuit.

A wireless communication device and a method for selecting a receiving mode are used to improve the throughput of the entire system. A SIR measurement component (106) measures the SIR of a known signal. A Doppler frequency detection component (108) detects the Doppler frequency from the received signal to measure a Doppler shift, wherein the Doppler shift is an indication of the speed at which the mobile station device is moving. Interference power measuring means (110) measures interference power from different cells. Known signal acquisition section (104), SIR measurement section (106), Doppler frequency detection section (108), and interference power measurement section (110) constitute propagation environment estimation section in this embodiment. Based on the SIR, Doppler offset, and interference power, the reception method selection section (112) selects one of two reception methods, RAKE reception or linear equalization.

The invention in use for wireless communication includes following steps: obtaining estimated value of channel from data signals of received baseband signals in training sequence signals of spread spectrum communication system; picking up a sample signal in spread spectrum sequence cycle from the said data signal; carrying out conjugate transformation for initial spread spectrum sequence; multiplying the transformed spread spectrum sequence by the said sampled signal, and then carrying out FFT; multiplying obtained Kth value by phase exp(- jk2Pi / N) so as to obtain sliding correlation value between received signal and initial spread spectrum sequence; based on estimated value of channel, carrying out multidiameter combination for sliding correlation value. The transmission data are obtained from spread spectrum sequence corresponding to maximum among combined values. Advantages are: reducing amount of calculation in channel estimation and Rake reception, increasing flexibility.

A rake reception apparatus for determining whether a paging channel is received in a mobile terminal using a Discontinuous Reception (DRX) mode. A searcher searches for a multi-path signal using a received signal output from a Radio Frequency (RF) part, and calculates an energy value for each hypothesis. A demodulator demodulates a Paging Indicator (PI) for a hypothesis for which an energy value calculated by the searcher exceeds a valid path threshold. A controller determines whether a paging channel is received, according to the demodulated signal output from the demodulator, and performs finger allocation using a multi-path search of the searcher if it is determined that the paging channel is transmitted.

The invention relates to a combined treatment method for intelligent antenna and Rake receiver in CDMA system. Wherein, it uses only one beam former for all multipath signals of every user and LMS adaptive algorithm to update array element weight vector. This invention has better bit error rate than that with beam former for every signal and reduces complexity for system realization.

A transmitting apparatus 100 spreads broadcast information by means of a spreading section 103, limits the band of spread broadcast information by means of a band limiting filter section 104 so as not to overlap a guard frequency band, adds the output signal of a band limiting filter section 104 to transmit data after an inverse Fourier transform by means of an adding section 105, modulates the resulting signal by means of a modulation section 106, and transmits it. A receiving apparatus 150 passes only a signal in a guard frequency band by means of a reception filter section 154, demodulates it by means of a demodulation section 155, despreads it by means of a despreading section 156, and performs rake reception by means of a rake reception section 157 to obtain broadcast information. By this means, guard frequency bands can be used efficiently, and spectrum efficiency can be improved.

An object of the present invention is to provide a rake receiver and a receiving method for efficiently assigning paths to fingers in a CDMA mobile communication system. In the present invention, a correlation-value calculation section 2 calculates correlation values between spreading codes and reception signals input from an input terminal 1, at all timings at which rake reception is possible, and outputs the calculated correlation values to a delayed-profile creation section 3 and a difference-history creation section 6. The delayed-profile creation section 3 determines average correlation values and issues the values as a delayed profile to a path selection section 4. For each reception timing, the difference-history creation section 6 compares the latest correlation value issued from the correlation-value calculation section 2 with a previous correlation value held by the difference-history creation section 6, to determine a difference history, and issues the difference history to the path selection section 4. The path selection section 4 rearranges the delayed profile in decreasing order the average correlation values. When the delayed profile and the difference history satisfy all predetermined conditions, the path selection section 4 assigns the corresponding reception timing to a finger and issues the reception timing to the finger section 5.

The invention in use for wireless communication includes following steps: obtaining estimated value of channel from data signals of received baseband signals in training sequence signals of spread spectrum communication system; picking up a sample signal in spread spectrum sequence cycle from the said data signal; carrying out conjugate transformation for initial spread spectrum sequence; multiplying the transformed spread spectrum sequence by the said sampled signal, and then carrying out FFT; multiplying obtained Kth value by phase exp(- jk2Pi / N) so as to obtain sliding correlation value between received signal and initial spread spectrum sequence; based on estimated value of channel, carrying out multidiameter combination for sliding correlation value. The transmission data are obtained from spread spectrum sequence corresponding to maximum among combined values. Advantages are: reducing amount of calculation in channel estimation and Rake reception, increasing flexibility.

A rake reception apparatus which receives and rake-combines spread signals on a path basis includes finger receivers (101-103), a switch (107), an adder (108); and a buffer (109). The finger receivers de-spread reception signals on a path basis. The switch sequentially selects de-spread data one by one on a path basis which are output from the plurality of finger receivers. The adder adds the data selected by the switch to a rake combining interim result corresponding to the data and outputs the result as a rake combining interim result after updating. The buffer holds the rake combining interim result output from the adder and outputs a rake combining interim result corresponding to data selected by the switch to the adder. A rake reception method is also disclosed.

Monitoring is made as to whether the serial number of header incorporated to the data sent to a Radio Link Control (RLC) after a decoding process is continuous. When it is determined as a result of monitoring for a predetermined period of time that no defect is present in the header numbers, a multi-path timing is detected by taking a correlation between the result of the detection and spread codes of received signals and a pilot signal. From this multi-path timing, a station, from which data are to be received in fingers, is determined for interrupting processes of de-spread, RAKE reception and decoding, thus reducing power consumed in the processes.

A receiving portion of a radio communication device includes a circuit periodically moving into a sleep mode of operation. The circuit periodically moves out of the sleep mode of operation in response to a re-activation signal. A first clock signal is generated and is counted. The re-activation signal is generated each time the number of the counted clock pulses in the first clock signal reaches an updatable number. A second clock signal is generated which has a frequency higher than a frequency of the first clock signal and is counted during every time interval determined by the first clock signal. An error of the frequency of the first clock signal with respect to the frequency of the second clock signal is calculated on the basis of a result of the counting to set an updatable number. The invention has a merit for reliably implementing RAKE reception.

A cellular radio communication system, a cellular radio communication method and a rake reception method for raising the efficiency of a baseband, and increasing the freedom of the structure of the radio base station. A cellular radio communication system comprises a baseband and first to Nth transmitter-receicvers connected by a transmission line. The baseband is provided with a modulator for producing, by a digital process, modulation signals to be sent from the first to Nth transmitter-receivers, and a demodulator for demodulating digital modulation signals received and analog-to-digital converted by the first to Nth transmitter-receivers. The transmitter-receiver is provided with a digital-to-analog converter for converting a digital modulation signal to a modulation signal to be sent, and an analog-to-digital converter for converting a received modulation signal to a digital modulation signal.

In a conventional RAKE synthesis reception device, when the spread ratio is small and the number of multi-paths is large, or when the interference signal power is large as compared to a desired signal power, suppression of the interference signal by the de-spreading processing is insufficient and the reception characteristic is significantly deteriorated. The reception spread signal which has been subjected to spread-encoding is subjected to de-spread processing by a spread code in a demodulation section / path synthesis section. The demodulation section / path synthesis section of the reception device for decoding by a decoding section includes a CIR estimation section for outputting a tap coefficient and a tap coefficient calculation section, so that the CIR estimation section and the tap coefficient calculation section are switched from one to the other by a switch device. The demodulation section / path synthesis section further includes an integration device for weighting the reception spread signal by the tap coefficient and synthesizing the signal and a de-spread section for de-spreading the synthesized signal by an assigned spread code. By sharing the interference suppression section with the conventional RAKE reception device, it is possible to reduce the circuit size.

In order to support channels for the HSUPA standard, a base station number is given to each finger at the time of RAKE reception so that the base station numbers can be discriminated from each other, thereby allowing RAKE reception to be performed separately for each different base station. Since a function to identify a base station to which each finger is assigned is provided, data from a base station 0 and data from a base station 1 can be combined as data from different base stations and thus correct data for each base station can be received.

The application provides an equalizer for realizing multipath diversity in a spread spectrum SC-FDE system, which comprises the following steps: channel estimation is performed by using a UW word vector of each SC-FDE symbol; first noise reduction is performed on a channel impulse response estimated by using each SC-FDE symbol in a Doppler variation domain; the result after the noise reduction is converted to a time domain to perform second noise reduction; and Rake reception is performed on a data block of a sending end by using the time domain impulse response after the noise reduction, so as to perform coherent combination on multipath information in all received data blocks. The application realizes coherent combination of multipath in a spread spectrum single carrier frequency domain equalization SC-FDE system by improving a channel estimation method and combining the advantages of Rake reception, instead of passive combination, so that the SC-FDE system can obtain better performance when passing through a multipath fading channel in a low signal-to-noise ratio scene.

The present invention can eliminate the multipath effect, channel interference and Doppler effect in mobile communication. The reception method includes the direct treatment of the received RF baseband signal with filter, multiplier and preset data and the direct feeding of the treated signal to the software adjudication decoder. The RAKE receiver of the present invention consists of matching filter, delay search tracker, predicting filter, smoothing filter, delay regulator, multiplier, multipath adder, filter parameter data base, S / N measuring comparator and one-out-of-three selector.

A rake reception device capable of allocating an appropriate number of fingers to a channel. In this device, a selection control section sets a finger allocated to the channel from the channel communication state and a control signal based on this setting is output to a synchronization processing section and to a selection switch. According to the control signal, the synchronization processing section detects a path and a spread code phase in a reception signal and allocates the detected path to the finger which has been set. The finger which has been set de-spreads the signal of the path allocated and performs synchronous detection. According to the control signal, the selection switch switches the connection between the finger and a maximum ratio combination section so that the output from the finger is output to the maximum ratio combination section.

The application discloses a multipath diversity receiving spread spectrum communication system suitable for urban channels and relates to the technical field of signal processing, which solves the problem of passive multipath coherent combination in the prior art. The system comprises the following steps: at the transmitting end, after input data streams pass through channel coding, interleaving and symbol mapping, serial-parallel conversion is performed, a data block is formed by adding block pilots after direct sequence spread spectrum using a spread spectrum code sequence, IFFT transformation is performed to the time domain, a cyclic prefix is introduced, and after serial conversion, the data block is sent into a multipath fading channel; at the receiving end, after serial-parallel conversion, the cyclic prefix is removed, FFT transformation is performed to the frequency domain, pilot channel estimation is performed, the pilots are removed, de-spreading and de-mapping are performed, channel estimation results and de-spreading data are mapped to the time domain by IFFT for RAKE reception, finally, soft information is added, demodulation, de-interleaving and decoding are performed; the multipath coherent combination is changed from passive to active, the multipath components can be better extracted, and the system has more superior performance under urban multipath channels.

The invention discloses a pulse radio ultra-wideband RAKE receiving and judging method in a high-speed mobile environment, and aims to solve the technical problem that a conventional pulse radio ultra-wideband RAKE receiving and judging method is complex. According to the technical scheme, the method comprises the following steps: sending data information bits according to a block structure, sending a data block to a receiving end through a channel after pulse is shaped, and obtaining a template signal vd (t) of an RAKE receiver after the receiving end is subjected to channel estimation; according to estimated doppler dimension change factors, carrying out doppler compensation for the template signal vd (t), so as to obtain a new RAKE receiving template signal v (t); carrying out RAKE receiving and judgment, so as to obtain sent information. The method estimates the dimension change factors by inserting pilot signals among block signals, and then utilizes the dimension change factors to determine the influence brought by the fact that the template signal is repeatedly collected in a repeated collection cycle to compensate the dopper effect. The method is simple and can greatly improve the bit error rate performance in the high-speed environment.