112 results about "Maximal-ratio combining" patented technology

Certain embodiments of the invention may be found in a method and system for antenna and radio front-end topologies for a system-on-a-chip (SOC) device that combines Bluetooth and IEEE 802.11 b / g WLAN technologies. A single chip radio device that supports WLAN and Bluetooth technologies receives a WLAN signal in a WLAN processing circuitry of the radio front-end and in a Bluetooth processing circuitry of the radio front-end. Signals generated by the WLAN processing circuitry and the Bluetooth processing circuitry from the received WLAN signal may be combined in a diversity combiner that utilizes selection diversity gain combining or maximal ratio combining (MRC). When a generated signal is below a threshold value, the signal may be dropped from the combining operation. A single antenna usage model may be utilized with the single chip radio device front-end topology to support WLAN and Bluetooth communications.

A network of wireless nodes transmit electromagnetic signals, typically in the radio frequency (RF) mode, or at other frequencies. Multiple infrastructure nodes pick up the signals transmitted by each wireless node. The signals are combined to estimate the actual signal transmitted by the wireless node, such as a leaf node sensor. Many different diversity techniques may be used to combine the signals. In one embodiment, maximal ratio combining, equal gain combining, selection combining or switching combining is used to combine the signals.

The present invention provides a method and system for operating a wireless communication system in which received signals from a plurality of antennas are weighted and combined with a beam forming operation to form an output signal. The beam forming operation determines weights adjusted to increase a desired signal power in the output signal while reducing the power in the output signal of out-of-band components. In an embodiment of the present invention, beam forming operations are performed with maximal ratio combining (MRC). Alternatively, a constant modulus algorithm (CMA) can be used for beam forming operations. In an alternate embodiment, improved interference suppression is performed with a novel algorithm referred to as an interference nulling algorithm (INA). The INA receives an error signal which is 180° out of phase with a combination of the channels for individual antennas, referred to as the SUM channel. The error signal is determined by complex conjugate multiplication of the individual signals and a reference complex signal. It is desirable to simultaneously achieve diversity and combining gain and suppress the adjacent channel by combining the weight generation for MRC and that for INA, as described above, to generate antenna weights similar to those of MMSE combining.

Soft-handoff methods involve receiving an uplink signal from a user equipment at more than one basestation. The uplink signals are processed at each basestation before being backhauled to a common point for use to derive a single signal from the user equipment. One problem with previous types of soft-handoff methods is that relatively complex processing is required at each basestation in order to demodulate and decode the signals. It is also desired to further increase uplink capacity as compared with known types of soft-handoff methods. This is achieved by backhauling signals without carrying out any decoding of the uplink signal at the basestation. The backhauled signals are combined at a common point using maximal ratio combining before being fully demodulated and decoded. As a result capacity is increased and required user equipment transmit power is reduced.

A beamforming device includes a Direction Of Arrival (DOA) estimation unit for estimating DOAs of the received signals based on a data subcarrier matrix; a pre-spatial filtering unit for using the estimated DOA, performing a filtering operation for the data subcarrier matrix, and generating filtering matrixes; a signal identification unit for using a data sequence, identifying original and interference signals, and generating the DOAs of the original and interference signals; a spatial filtering unit for generating an interference-plus-noise covariance matrix by using the DOA of the interference signal, eliminating the interference signal by using the covariance matrix and the DOA of the original signal, and forming final beams for the original signal; and a channel estimating and signal combining unit for performing a maximal ratio combining operation so that the final beams are combined as one combined final beam.

Soft-handoff methods involve receiving an uplink signal from a user equipment at more than one basestation. The uplink signals are processed at each basestation before being backhauled to a common point for use to derive a single signal from the user equipment. One problem with previous types of soft-handoff methods is that relatively complex processing is required at each basestation in order to demodulate and decode the signals. It is also desired to further increase uplink capacity as compared with known types of soft-handoff methods. This is achieved by backhauling signals without carrying out any decoding of the uplink signal at the basestation. The backhauled signals are combined at a common point using maximal ratio combining before being fully demodulated and decoded. As a result capacity is increased and required user equipment transmit power is reduced.

A multiple-input-multiple-output (MIMO) receiving system configured for receiving multiple transmission layers is provided herein. The system includes a plurality of beamformed tunable receiving antennas configured to receive a plurality of transmitted layers; and a control module configured to select for the beamformed antennas a single set of discrete weights for tuning said antennas for all of the transmitted layers so that the weights are selected for optimal performance of said receiving system, wherein said selection is carried out based on an extended Maximal Ratio Combining (MRC) metric or other quality metric measured by the MIMO baseband module, and using said measured metric separately for each beamformed antenna to determine gain or attenuation independently of phase selection.

A wireless network device (4), such as a wireless media centre, has orthogonally polarised antennas (6a, 6b) arranged to provide transmit and / or receive polarisation diversity. The antennas may be arranged so that their nulls do not coincide, to produce a combined antenna pattern with a low variation of gain with direction. The antennas may be collocated, but arranged orthogonally. Preferably, the combined antenna pattern is substantially omnidirectional in elevation as well as azimuth. This arrangement provides uniform coverage in a 3D environment. The transmitter may transmit data using polarisation-time block codes. A wireless receiver (10, 18) for use in the wireless network may have either one antenna or two orthogonally polarised antennas. The receiver (10, 18) applies maximal ratio combining to the received signals. The signals may be OFDM signals and the receiver applies maximal ratio combining independently to each frequency channel. The antennas may be flat linear or annular slot antennas, which provide strongly polarised beams and can be integrated within the housing of the devices.

The present invention relates to use of a smart antenna for a RF reader on a Radio Frequency Identification (RFID) system to significantly increase the operating range of the RFID system. The smart antenna can be an adaptive antenna array. The smart antenna comprises a plurality of antenna elements and, by combining the signals from multiple antenna elements, significantly increases the received signal-to-noise ratio. In a noise limited environment, combining the signals to maximize the received signal-to-noise ratio can be based on the maximal ratio combining (MRC) principle. To achieve the best signal quality, the received signal from each antenna can be phase-shifted such that the resultant signals from all antennas are in phase. In addition, the signal from each antenna can be scaled in amplitude based on the square root of its received signal-to-noise ratio.

The present invention provides a method and system for operating a wireless communication system in which received signals from a plurality of antennas are weighted and combined with a beam forming operation to form an output signal. In an embodiment of the present invention, beamforming operations are performed with maximal ratio combining (MRC) and an interference nulling algorithm (INA). The INA receives an error signal which is 180° out of phase with a combination of the channels for individual antennas, referred to as the SUM channel. The error signal is determined by complex conjugate multiplication of the individual signals and a reference complex signal. The weight amplitude is controlled by weight normalization to provide faster convergence and prevent integrator overflow.

The present invention relates to use of a smart antenna for a RF reader on a Radio Frequency Identification (RFID) system to significantly increase the operating range of the RFID system. The smart antenna can be an adaptive antenna array. The smart antenna comprises a plurality of antenna elements and, by combining the signals from multiple antenna elements, significantly increases the received signal-to-noise ratio. In a noise limited environment, combining the signals to maximize the received signal-to-noise ratio can be based on the maximal ratio combining (MRC) principle. To achieve the best signal quality, the received signal from each antenna can be phase-shifted such that the resultant signals from all antennas are in phase. In addition, the signal from each antenna can be scaled in amplitude based on the square root of its received signal-to-noise ratio.

The invention belongs to the technical field of wireless communication and specifically relates to a phase noise compensation and suppression method for a large-scale MIMO system. The method providedby the invention mainly comprises the steps of carrying out maximal-ratio combining on receiving signals of antennas under the condition of assuming that phase noise is zero, thereby obtaining an initial value of a data symbol; carrying out iteration according to the obtained initial value through adoption of a variational Bayesian algorithm, wherein an estimation value of the data symbol is converged to a stable value under the condition that the receiving signal ri is known. The method has the beneficial effects that the data symbol can be judged in a high-order modulation mode within the large-scale MIMO system; and according to a judgment method, the inversion operation of a high-dimensional matrix is avoided in a traditional variational Bayesian inference algorithm, and the inversionoperation of the high-dimensional matrix is converted into the inversion operation of a diagonal matrix, so the system complexity is reduced, and the system performance is improved.

The invention discloses an artificial noise precoding secure transmission method for a full duplex relay system. The method comprises the following steps: an information source adopts an artificial noise precoding scheme to simultaneously broadcast useful signals and artificial noise signals; a relay receives the signals broadcast by the information source and the self-interference at the relay, and a wiretapper receives the signals broadcast by the information source and recoding signals transmitted by the relay; a relay node reduces the influence caused by the self-interference by adopting a self-interference elimination technique; an information sink receives the transmitted signals that are recoded by the relay by adopting a maximal-ratio combining strategy; the signal to interference and noise ratios of the information source to a relay link and the relay to an information sink link are obtained, and the received signal to interference and noise ratios at the information sink and the wiretapper are also calculated; and the instantaneous safety rate of the system is obtained according to the received signal to interference and noise ratios at the information sink and the wiretapper, and an average safety rate is calculated. According to the method disclosed by the invention, the legal channel transmission rate can be increased, and the capacity of wiretap channels can also be effectively reduced.

The present invention provides a method of quantifying a signal to noise ratio (SNR) gap between diversity combining schemes that are operable to process multi-path wireless communications for an arbitrary number of diversity branches. The method determines the gap in a without the need to determine or know the SNR for each individual diversity combining scheme. This involves determining the number of diversity branches associated with the multi-path wireless communication and the receiver used to process the multi-path wireless communication. The SNR gap may then be expressed as the term 10log10L! / L where L is the number of diversity branches.

The invention discloses a full duplex scrambling transmission method in an untrusted relay network, which is applied to a wireless communication system including three nodes of an information source, a relay and a destination node, and the relay is an untrusted relay. The method comprises the following steps: in a first time slot, transmitting information to the relay and the destination node by the information source, and receiving information source information by the destination node and transmitting an interference signal to the relay; in a second time slot, amplifying the signal received in the first time slot by the relay by adopting an amplify-and-forward protocol, after that, forwarding the signal to the destination node; performing self-interference cancellation by the destination node according to estimated channel information, and performing maximal-ratio combining on information received in the first time slot and the second time slot; and calculating the instantaneous security capacity of the system according to the received signal to noise of the relay in the first time slot and the received signal to noise of the destination node in the two time slots. The method of the invention can not only make the information source send the information to the destination node efficiently, but also make the destination node effectively interfere with the relay node to receive useful information, so as to maximize the security capacity of the system.

The invention discloses a safety transmission method based on manual noise and beam forming in a downlink full-duplex relay network. The method comprises two stages: in a first stage, a full-duplex relay receives signals of a base station and transmits interference signals to an eavesdropper to puzzle the eavesdropper; and in a second stage, the relay combines amplified signals with the manual noise and transmits the combined signals and noise to a legal receiving terminal, wherein the legal receiving terminal obtains private signals transmitted by the base station through direct decoding, andthe eavesdropper tries to obtain the private signals by employing maximal-ratio combining. The network successfully puzzles the eavesdropper through the design of manual noise and beam forming of a relay node. To maximize the safety transmission rate of the network, a corresponding constraint condition and an optimization problem are made. According to the method, through solution of the optimization problem, safety transmission based on manual noise and beam forming in the downlink full-duplex relay network is realized.

A COFDM demodulator providing independent DQPSK symbol amplitude and phase equalization provides improved soft-symbol estimates by reducing the possibility of clipping in the differential demodulator, improving the tolerance of the differential demodulator to finite word length effects, correcting for phase drifting between adjacent subcarriers, and improving signal-to-noise ratio (SNR) calculation accuracy for maximal ratio combining applications. Separate acquisition and tracking modes for the amplitude and phase equalizers are provided that handle start-up, reacquisition, and steady-state operation of the demodulator.

The amplify and forward relay method enhances QOS in wireless networks and is based on the switch-and-examine (SEC) and SEC post-selection (SECps) diversity combining techniques where only a single relay out of multiple relays is used to forward the source signal to the destination. The selection process is performed based on a predetermined switching threshold. Maximal-ratio combining (MRC) is used at the destination to combine the signal on the relay path with that on the direct link.

The invention relates to a secure transmission method adopting information source and relay-combined transmitting antenna selection. The method includes the following steps that: in a first time slot, and an information source obtains channel state information from a relay and selects an antenna which makes the received signal to noise of the relay maximum to broadcast confidential signals according to the channel state information, and other three nodes receive signals through adopting maximal-ratio combining; in a second time slot, the relay adaptively decodes a forwarding protocol, when the relay can correctly decode the forwarding protocol, the relay obtains channel state information from an information sink and selects one antenna which makes the received signal to noise of the information sink maximum to forward confidential signals according to the channel state information from the information sink; and when the relay cannot correctly decode the forwarding protocol, the information source obtains the channel state information from the information sink and selects an antenna which makes the received signal to noise of the information sink maximum to retransmit the confidential signals in the first time slot, and the information sink and the relay receive the signals with maximal-ratio combining. According to the method of the invention, transmitting antenna selection technology is adopted to maximize the received signal to noise ratio of the relay or the information sink, and the received signal to noise ratio of an eavesdropper can be decreased, and low complexity and high security can be achieved.

The invention discloses a polarity diversity reception method based on an SOQPSK-TG signal. The method comprises the following steps: adopting two ADCs to transfer a received levogyration polarity signal and a received dextrorotation polarity signal into digital signals respectively; adopting an automatic gain control loop to enable the two digital signals to be constant in amplitude or in a threshold value section; tracking frequency difference and phase difference of the two gained digital signals through a difference module loop to fulfill same frequency and phase locking of the two digital signals; adopting maximal-ratio combining to obtain average SNR gain; tracking Doppler frequency shift to conduct carrier recovery; conducting position timing clock recovery; tracking clock phase shift and frequency shift between a receiver and a transmitter. The invention further discloses an SOQPSK-TG signal modulation and polarity diversity reception device based on FPGA. The modulation and reception device utilizes the characteristics of constant envelope and high spectral efficiency of the SOQPSK-TG to meet modern satellite communication demand; the polarity diversity reception technology is introduced to avoid deep zero point influence; system performance is improved.

The invention discloses a method and device for frequency domain equalization detection. The method comprises the steps that a time domain signal interference noise ratio (SINR) and a noise interference covariance matrix Re_pilot of a pilot frequency subcarrier are calculated; the noise interference covariance matrix Re_pilot of the pilot frequency subcarrier is utilized for calculating a noise interference ratio (NIR); the time domain SINR and the NIR are utilized for determining the adoption of an interference rejection combining (IRC) detection mode or a maximal ratio combining (MRC) detection mode to conduct the frequency domain equalization detection. According to the method and device for the frequency domain equalization detection, the frequency domain equalization detection is conducted in the mode that the MRC detection mode or the IRC detection mode is selected in a self-adaptive pattern, therefore, when interference plays a leading role in receiving signals, the interference and noise can be distinguished and processed, and the detection performance can be fully guaranteed; when the interference does not play a leading role in receiving the signals, the situation that computational accuracy is lowered due to the introduction of channel estimation errors cannot occur, and therefore the detection performance can be fully guaranteed.

The invention provides a dual-medium hybrid fading communication system performance analysis method based on an AF (Amplify and Forward) protocol, and belongs to the technical field of dual-medium cooperative communications. The method comprises the following steps: establishing a Moment Generating Function (MGF) model that satisfies the signal-to-noise ratio of a wireless link in the Nakagami distribution; establishing an MGF model that satisfies the signal-to-noise ratio of a power line link in the logarithmic normal distribution; according to the two MGF models respectively established in the above steps, determining an MGF model of the total signal-to-noise ratio of a system under Maximal Ratio Combining (MRC); and determining the bit error rate and outage probability of the system according to the system total signal-to-noise ratio MGF model. According to the dual-medium hybrid fading communication system performance analysis method based on the AF protocol provided by the invention, the system performance calculation complexity is simplified, optimal distribution parameters of system performance can be obtained, and a theoretical expression of the bit error rate and the outage probability of the system can be calculated approximately.

The invention discloses a transmitting light path selecting method for combined diversity reception in MIMO (Multiple-input and Multiple-Output)free space optical communication, and belongs to the technical field of MIMO free space optical communication. The transmitting light path selecting method comprises the following steps of: carrying out comparison on the light intensity gain after the gains from each laser to Nr detectors and the like are combined to obtain a serial number of the laser with maximum light intensity gain value, and then feedbacking the serial number of the laser to a light path selector at a transmitting end by a low-speed feedback channel so as to enable the transmitting end to select and activate the optimal laser for transmitting light signals. The method disclosed by the invention has the advantages that the system performances of the MIMO free space optical communication modulated on basis of OOK (On-Off Keying) are obviously improved, and compared with maximal-ratio combining reception, the complexity for realizing the method of united equal-gain combining reception, adopted by the invention, on hardware can be reduced.

The invention relates to the wireless communication field and discloses a multiple-input multiple-output detection method and system for received data. According to the multiple-input multiple-output detection method and system, at least one resource element (RE) is selected from a resource block where the received data to be detected are located; detection SINRs of the selected RE are calculated through a maximal ratio combining (MRC) detection algorithm and an interference rejection combining (IRC) detection algorithm respectively; the detection SINR obtained through calculation with the MRC detection algorithm is compared with the detection SINR obtained through calculation with the IRC detection algorithm; according to a comparison result, the detection algorithm through which the higher detection SINR is obtained is selected for conducting multiple-input multiple-output detection on the received data to be detected. Since the detection performance of the MRC detection algorithm and the IRC detection algorithm is prejudged directly through calculation and comparison of the detection SINRs, selection and switch of the MRC detection algorithm and the IRC detection algorithm can be conducted accurately in real time with no need for judging an interference environment where a terminal is currently located, and therefore the overall performance of an LTE terminal in terms of MIMO detection is improved.

A beamforming device includes a Direction Of Arrival (DOA) estimation unit for estimating DOAs of the received signals based on a data subcarrier matrix; a pre-spatial filtering unit for using the estimated DOA, performing a filtering operation for the data subcarrier matrix, and generating filtering matrixes; a signal identification unit for using a data sequence, identifying original and interference signals, and generating the DOAs of the original and interference signals; a spatial filtering unit for generating an interference-plus-noise covariance matrix by using the DOA of the interference signal, eliminating the interference signal by using the covariance matrix and the DOA of the original signal, and forming final beams for the original signal; and a channel estimating and signal combining unit for performing a maximal ratio combining operation so that the final beams are combined as one combined final beam.

The invention is applicable to the field of wireless communication, and provides a search method for the best communication location of multiple mobile relays. The method comprises the following steps: (A) mobile relays receive a training sequence sent by a source end in any position of a fixed orbit, and transmit the training sequence to a destination end; (B) the destination end receives independent fading signals from the mobile relays and performs maximal-ratio combining, and then, generates single-bit information according to the combining result in each time slot and feeds the single-bit information back to all the mobile relays through broadcasting; and (C) the mobile relays record the current location information, perform calculation according to the single-bit information and move according to the calculation result, the method returns to step A, and finally, the best relay communication position is determined. According to the search method provided by the invention, an airborne single antenna is used, there is neither need to rely on GPS nor need to know the location information of a ground communication unit, and the mobile relays can find the best relay communication location within a given movement trajectory range only by use of the bit information fed-back by the destination end.

The invention discloses a multi-channel signal synchronization and diversity combining device and method. The method comprises the following steps: receiving multi-channel diversity signals, and calculating the signal-to-noise ratio (SNR) of the signals of each channel according to the multi-channel diversity signals; selecting the signals of any channel as reference signals, and carrying out orthogonal down-conversion and low-pass filtering on the signals of each channel; carrying out inner ring phase discrimination and loop filtering on the reference signals and the signals of the other channels; respectively carrying out maximal-ratio combining on all same-phase branches and orthogonal branches that are obtained through the low-pass filtering; carrying out outer ring phase discrimination and loop filtering on maximal-ratio combining results; completing pre-combining same-frequency and same-phase adjustments of the multi-channel signals jointly through a plurality of differential mode rings and an overall common mode ring; and completing calculation of weights of the signals of each channel during the combining through SNR estimations, so that the maximal-ratio combining is completed. The method has the advantages that the implementation is easy; and a larger combining gain can be provided, so that the information transmission quality is improved.

The invention discloses a self-adaption relay communication method based on ladder modulation. The method comprises the steps: (1) obtaining basic layer data and strengthening layer data; (2) adding cyclic redundancy check (CRC) codes; (3) conducting convolution and coding; (4) obtaining a sending data matrix; (5) confirming a star map; (6) modulating sending data; (7) sending a relay noise signal; (8) conducting self-adaption choosing processing; (9) sending a direct route signal and a relay route signal; (10) combining signals; (11) conducting demodulation, convolution and decoding; and (12) removing the check codes. Ladder modulation, relay node self-adaption choosing processing and a maximal-ratio combining method are adopted by the self-adaption relay communication method to complete self-adaption relay communications based on the ladder modulation, according to different error code conditions, self-adaption choosing processing of relay nodes is allowed, error code rate of data of various routes can achieved independent controlling, the basic layer data and the strengthening layer data are fully and reasonably utilized, and error code performance of a whole system is improved.

The present invention discloses a matched filtering circuit apparatus in the baseband processing system of the terminal device and method thereof. The circuit apparatus comprises a control unit for controlling the processing procedures of de-scrambling, de-spreading, de-rotating and maximal ratio combining data, the output ports of the control unit connects with a V vector buffer unit, a shift integral selection unit and a coherent integral unit for implementing the matched filtering and data buffer. Due to the application of entirely pipeline design structure, the processes of data buffer and matched filtering can be carried out simultaneously, thus shortening time consumption of the terminal hardware accelerator and effectively improving the operation efficiency of the mobile communication terminal hardware system.

The invention discloses a full-duplex opportunistic relaying protocol self-adaptation switching security transmission scheme. The scheme is applied to a system including an information source, a relay, an information sink and an eavesdropper. According to the scheme, information is transmitted to the relay through the information source, the relay can perform transmission by selecting an antenna which can maximize the received signal to noise ratio of the information sink, maximal-ratio combining is performed by means of other antennas, and information of the information source is received; in the process, it is supposed that the relay can obtain channel state information of the information sink and the eavesdropper, the average security speed of the system is estimated by means of the information, and transmission is performed by selecting the best relay protocol from an amplifying-forwarding protocol and a decoding-forwarding protocol. The system security speed is a comparison condition, the two main protocols are automatically switched, and the evaluation security speed of the system can be increased and the evaluation security performance of the system can be improved by selecting the best relay protocol according to scenes in a self-adaptation mode.