223results about How to "Increase diversity gain" patented technology

The present invention utilizes adaptive antenna arrays at a base station to increase the forward link capacity of mobile data systems. One or more simultaneous forward link beams are formed and are switched (or hopped) in a time division manner among subscribers. The beam hopping sequence is randomized by varying the time slot and / or carrier frequency of each subscriber. In space-time hopping, the position within a frame of the time slot for each subscriber is varied in a pseudo random sequence. In space-frequency hopping, the carrier frequency for each frame is varied in a pseudo random sequence. The pseudo random beam hopping sequence provides a gain due to interference diversity in addition to the antenna array gain. Forward link beam forming algorithms use space-time or space-frequency hopping to increase the capacity of mobile data systems.

A method is provided for allocating resources of a control channel in a mobile communication system using Orthogonal Frequency Division Multiplexing (OFDM). The method includes, when a time index and a frequency index of available Resource Elements (REs) are defined as l and k, respectively, dividing the available REs in a two-dimensional structure of (k, l); and time-first-allocating each RE to a plurality of RE groups while increasing the time index l for each frequency index k from an initial value up to a predetermined range.

The present invention provides an apparatus and method of multiple antenna receiver combining of high data rate wideband packetized wireless communication signals, where the apparatus includes M receive antennas, receiving M high data rate wideband packetized wireless communication signals, where each of the signals includes N frequency bins. The apparatus, in an exemplary embodiment, includes (1) a joint timing recovery units that perform joint coarse signal timing estimation, joint frequency offset estimation, and joint fine timing estimation on each of the signals, (2) M Fast Fourier Transform units (FFTs) that each convert the digital data for each of the M signals into frequency domain information for each of the N received frequencies and that output Q pilots for each of the signals, where Q is a positive integer, and (3) a combiner that weights and combines the outputs of the M FFTs for each of the N received frequencies.

An STBC encoding extension method for more than two transmit antennas, which provides higher diversity gains while keeping the same coding / decoding latency as in the two-transmit-antenna case of conventional STBC encoding. A N×2 STBC encoder is constructed from a 2×2 STBC encoder, wherein the N×2 STBC encoder is suitable for transmission with higher numbers of transmit antennas including wireless transmission systems with N×1 antenna configurations where N>2.

A method of transmitting a downlink control signal is disclosed, by which localized allocation and distributed allocation are efficiently used in transmitting a downlink control signal. The present invention includes multiplexing the downlink control signal in a manner of if there exists downlink data transmission to a prescribed UE, applying localized allocation to a transmission of the downlink control signal including the scheduling information on the uplink data transmission of the UE and applying distributed allocation to another transmission of the downlink control signal and transmitting the multiplexed downlink control signal.

A diversity receiver is provided with antennas (1a) and (1b) in a first branch and antennas (1c) and (1d) in a second branch each of which antenna gains is controlled so that the offset between the directions of directional radiation patterns for the first and second branches becomes approximately π / 2. Thereby, the diversity receiver can obtain a sufficient diversity gain even when it is incorporated into an indoor television with the antennas being built thereinto in close vicinity to one another.

Data streams stored in buffers (101) are modulated by modulation sections (102). Multipliers (103) multiply the signals output from the modulation sections (102) by weights output from a weight control section (112). The signals output from the multipliers (103) are added up by addition sections (104), subjected to radio transmission processing by transmission radio sections (105) and sent through antennas (106). A buffer control section (111) controls the buffers (101) based on a retransmission count output from a retransmission count detection section (110). The weight control section (112) outputs weights different from weights at the time of previous transmission to the multipliers (103) every time data is retransmitted. This allows a diversity gain at the time of data retransmission to be increased even if a time variation of the propagation path environment for radio signals is slow.

A method of transmitting a downlink control signal is disclosed, by which localized allocation and distributed allocation are efficiently used in transmitting a downlink control signal. The present invention includes multiplexing the downlink control signal in a manner of if there exists downlink data transmission to a prescribed UE, applying localized allocation to a transmission of the downlink control signal including the scheduling information on the uplink data transmission of the UE and applying distributed allocation to another transmission of the downlink control signal and transmitting the multiplexed downlink control signal.

A method for transmitting a multiple codeword (MCW) in a Multiple Input Multiple Output (MIMO) communication system is disclosed. A method for transmitting a multiple codeword (MCW) in a Multiple-Input Multiple-Output (MIMO) communication system includes performing a channel coding and modulation process for each codeword of the multiple codeword (MCW), multiplying the channel-coded-modulated result by a rotation matrix decided by either a spatial multiplexing rate or a layer (R), and performing a codeword permutation (CP) on the multiple codeword (MCW), performing a MIMO encoding on the multiple codeword (MCW), and transmitting the multiple codeword (MCW) via a multi-antenna.

The utility model discloses an interference elimination method in cooperative community, which comprises an S102, a coordinator of a base station getting characteristic information of users of strong interference; an S106, a coordinator of a base station and the base station performing interference elimination based on the information and the characteristic information of users of strong interference. The utility model has advantages of making best use of interference information, improving diversity gain of multi-user, and improving the system uplink capacity as the method considers the interference information elimination between inter-cells.

The invention discloses a broadband power line carrier communication physical layer emission signal processing method based on OFDM. The method includes: receiving data from a link layer, and dividing the data into frame control data and load data; performing channel coding on the frame control data and the load data, and modulating the frame control data and the load data after channel coding to subcarriers; performing inverse Fourier transform on the modulated frame control data and the load data, performing power control, and generating a time domain frame control symbol and a time domain load symbol; and adding a cyclic prefix to the time domain frame control symbol and the time domain load symbol, adding a time domain leading symbol, performing windowing processing, and generating physical layer emission signals. According to the method, the utilization rate of the frequency band is high, the transmission rate is high, and the intersymbol interference resistance and the channel fading resistance are excellent.

An improved interleaver design to fully explore the diversity of the MIMO OFDM systems provides higher diversity gain than usual. A method for wireless data communication using such interleaver design implements parsing a bit stream into multiple spatial data streams, interleaving the bits in each spatial data stream by performing bit circulation and column swapping to increase diversity of the wireless system, and transmitting the bits of each spatial data stream.

Disclosed is a method for allocating resources in a base station of a wireless communication system that performs communication using frequency resources. The method includes dividing subcarriers into subcarrier sets each including a predetermined number of consecutive subcarriers, and generating a resource index table mapped to consecutive indexes such that a distance between subcarriers in the subcarrier sets is maximized; and determining an amount of resources to be transmitted through a downlink according to a channel condition, for data to be transmitted to each terminal, and allocating resources to the terminal using the index value in the resource index table.

A pre-coding method for improving diversity gain in an Orthogonal Frequency Division Multiplexing (OFDM) system and a transmission apparatus and method are disclosed. The transmission method includes converting an input transmission signal into parallel signals, pre-coding the parallel signals with a predetermined frequency offset, performing Inverse Discrete Fourier Transform (IDFT) on the pre-coded signals, and up-converting the IDFT signals and outputting the up-converted signals to a wireless network. By performing pre-coding on a transmission signal with a frequency offset in an OFDM system, diversity gain can be improved.

The invention provides a user selecting and dispatching method used in a downlink MIMO (Multiple Input Multiple Output) transmission process, comprising the steps of: carrying out complementary matching to each user subgroup with same PMIs (Precoding Matrix Indicators) to obtain candidate user combinations on the basis of a preset dispatching criterion according to information fed back by users in a SU (Single User)-MIMO feedback mode, and selecting dispatched MU (Multiple User)-MIMO transmission user combination from all the candidate user combinations. The invention further provides a user feedback as well as user selecting and dispatching method used in the downlink MIMO transmission process, comprising the step of: carrying out matching on the basis of the preset dispatching criterion according to at least two channel quality indicators fed back by each user so as to determine the dispatched MU-MIMO transmission user combination. The invention further provides a device for executing the method. The method and the device in the invention benefits the improvement of system throughput, the enlargement of use selection range, and the solving of the problems of mutual interference among users and mismatching CQI (Channel Quality Indicator). The multiple CQI feedback mechanism provided in the invention supports the multi-code word or multi-data stream transmission of users in the MU-MIMO transmission and can acquire better multi-user diversity gain.

It is an object of the present invention to improve the diversity gain by conducting linear prediction of fading fluctuations and switching antennas. In order to attain this object, the diversity receiver in accordance with the present invention comprises a plurality of antennas for receiving wireless signals subjected to direct spread modulation, an antenna switch for conducting antenna connection switching thereof, a primary demodulator for demodulating the wireless signals and obtaining a spread spectrum signal, a matched filter for finding a correlation value of the spread spectrum signal and a spread code for demodulation, a mean value computation unit for finding a mean SNR of the received signal by converting the maximum correlation value to a value per 1 frame, an estimation unit for linear prediction of the SNR of the received signal based on the time series data of the mean SNR, and a level comparator for comparing the SNR of the received signal that was predicted by the estimation unit with a threshold value and outputting a control signal for conducting antenna switching to the antenna switch.

It is an object of the present invention to improve the diversity gain by conducting linear prediction of fading fluctuations and switching antennas. In order to attain this object, the diversity receiver in accordance with the present invention comprises a plurality of antennas for receiving wireless signals subjected to direct spread modulation, an antenna switch for conducting antenna connection switching thereof, a primary demodulator for demodulating the wireless signals and obtaining a spread spectrum signal, a matched filter for finding a correlation value of the spread spectrum signal and a spread code for demodulation, a mean value computation unit for finding a mean SNR of the received signal by converting the maximum correlation value to a value per 1 frame, an estimation unit for linear prediction of the SNR of the received signal based on the time series data of the mean SNR, and a level comparator for comparing the SNR of the received signal that was predicted by the estimation unit with a threshold value and outputting a control signal for conducting antenna switching to the antenna switch.

A scalable subscriber terminal for bi-directional communication with a gateway through one or more satellites is provided according to another embodiment of the invention. The scalable subscriber terminal may comprise a plurality of antennas and be configured to operate in at least a first communication mode prior to switching to a second communication mode. The first communication mode may comprise communicating with the gateway through a first satellite. The second communication mode may include communicating with the gateway through the first satellite and a second transceiver. The scalable subscriber terminal may download MIMO operational firmware from the gateway through the first satellite prior to switching to the second communication mode. The first communication mode may be a SISO or SIMO mode. The second communication mode may be a MISO or MIMO mode. The second transceiver may be a second satellite or a terrestrial repeater.

Data streams stored in buffers (101) are modulated by modulation sections (102). Multipliers (103) multiply the signals output from the modulation sections (102) by weights output from a weight control section (112). The signals output from the multipliers (103) are added up by addition sections (104), subjected to radio transmission processing by transmission radio sections (105) and sent through antennas (106). A buffer control section (111) controls the buffers (101) based on a retransmission count output from a retransmission count detection section (110). The weight control section (112) outputs weights different from weights at the time of previous transmission to the multipliers (103) every time data is retransmitted. This allows a diversity gain at the time of data retransmission to be increased even if a time variation of the propagation path environment for radio signals is slow.

This invention provides a method for exploiting precoder optimization gains and multi-user diversity gains with interference alignment in general MIMO wireless networks including multiple users. Specifically, two embodiments exploit either a gradient-based search or iteratively orthogonalizing inference. The method can achieve near-optimal performance at a low complexity. Furthermore, a scheduling criterion is provided for wireless networks comprised of a large number of mobile stations in each cell. The criterion can be done independently in each cell to significantly reduce information exchanged between base stations in different cells compared to the methods that perform joint scheduling over all cells. The two embodiments can be utilized in a spectrally efficient communications network equipped with relaying nodes.

Systems and methods are provided for employing a HARQ retransmission scheme in a time invariant MIMO transmission channel with two inputs. During odd-numbered transmission attempts of information bearing signal s, the original signal s is sent. During even-numbered transmission attempts, a signal {hacek over (s)} that is different from but represents the same information as s is sent. By alternating between two different signals during retransmission, diversity gain is introduced. Information bearing signals s and {hacek over (s)} may also be subjected to precoding before transmission. The result of precoding is a channel that effectively changes with time. A receiver that operates using this retransmission scheme may use the information from some or all of the transmission attempts. The receiver may include a pre-processor for space-time codes that effectively converts {hacek over (s)} into an s representation.

A transmission method and a base transceiver station applying antenna hopping between at least two antenna elements are provided. According to one embodiment of the invention, a carrier carrying a first signal and a second signal is transmitted. At least a portion of the first signal is subjected to a measurement for adjusting receive characteristics of a mobile station for the reception of at least a portion of the second signal. Antenna hopping is applied to the carrier such that the at least a portion of the first signal and the at least a portion of the second signal are transmitted during an interval between two consecutive antenna hops between the at least two antenna elements.

The invention provides a space-time block coded spatial modulation method, belongs to the technical field of communication and is used for improving diversity gain of a system. The method comprises the steps that an input information bit sequence is allocated; space constellation matrix selection is carried out on a previous part of bits; constellation symbol mapping is carried out on a rear partof bits; modulated symbols are preprocessed through a P matrix to obtain new modulation symbols; cross processing is carried out on the new modulation symbols; a novel space-time block coded codewordmatrix X is obtained through coding; and the codewords C of a novel space-time block coded spatial modulation scheme are obtained; in order to ensure full diversity, corresponding phase rotation is carried out on transmitted codewords; the codewords are not overlapped with each other; and the full diversity space-time coded design is realized. According to the method, a single mapping symbol is coded and then is allocated to different transmitting antennas for transmission in a plurality of time slots, the diversity gain is clearly improved, and the bit error rate performance of the system isimproved.

The invention discloses an interleaving method in an orthogonal frequency division multiplexing system and a device thereof. The method comprises that: S1. plural symbol sequences to be transmitted are divided into a real part and an imaginary part, i.e. two paths of same-phase and orthogonal symbol sequences; S2. the same-phase or the orthogonal paths of symbol sequences are maintained to be unchanged, another path of symbol sequences are divided into multiple groups in turn, and intra-group interleaving is performed in each group; S3. the same-phase or the orthogonal paths of symbol sequences which are not interleaved in the step S2 are recombined with the another path of symbols after interleaving so that new plural symbol sequences are formed and are called first plural symbol sequences; S4. symbol interleaving is performed on the first plural symbol sequences so that second plural symbol sequences are obtained; S5. and orthogonal frequency division multiplexing modulation is performed on the second plural symbol sequences. Time, frequency and signal space diversity gain of the orthogonal frequency division multiplexing system are enhanced. Meanwhile, higher throughput and lower realization complexity are maintained.

A method is provided for allocating resources of a control channel in a mobile communication system using Orthogonal Frequency Division Multiplexing (OFDM). The method includes, when a time index and a frequency index of available Resource Elements (REs) are defined as l and k, respectively, dividing the available REs in a two-dimensional structure of (k, l); and time-first-allocating each RE to a plurality of RE groups while increasing the time index l for each frequency index k from an initial value up to a predetermined range.

The present disclosure relates to a sparse-coded ambient backscatter communication method and a system. According to the sparse-coded ambient backscatter communication method, in an ambient backscatter system including an access point and a plurality of sensor nodes, each sensor node transmits a code word in a non-orthogonal multiple access (NOMA) manner using sparsity of a signal by a duty cycling operation and the access point detects a superimposed signal transmitted in the NOMA manner by an iterative decoding method in which a dyadic channel and intersymbol interference are reflected. The present disclosure may reduce the implementation cost by reducing the number of impedances required to modulate data of a batteryless sensor node in an Internet of Things environment and utilize the dyadic backscatter channel to detect a signal, thereby providing massive connectivity of the access point.

The invention discloses an interference suppression method for a multi-user MIMO collaborative relay system, mainly solving the problem that each user has multiple antennas in a common-channel multi-user relay system. The interference suppression method comprises the steps that: a user determines a beamforming vector by adopting a signal space alignment method, and sends out a signal after weighting the signal with the beamforming vector in a multiple-access time slot; a relay constructs a precoding matrix based on an orthogonal projection principle, and amplifies and sends the received signal after precoding; the user receives the signal and suppresses interference signals between user pairs by adopting a decoding vector, and conducts a maximum likelihood detection to obtain the needed signal. According to the invention, a network transmission rate and a resource utilization rate are improved, diversity gains of multiple antennas are achieved, channel fading resisting capability of the system is enhanced, and a bit error ratio is decreased. Further, the interference suppression method of the invention can be applied in a transmission mode under centralized management and control of a wireless ad hoc network and base station, wherein data can be exchanged directly through user-relay-user mode.

Disclosed is a method for determining precoding matrix based on an open-loop MIMO scheme, which can enhance a diversity gain at a static communication environment or a low-mobility communication environment. The method for determining precoding matrix applies a first precoding matrix to downstream data to transmit the downstream data through a plurality of antennas, the first precoding matrix being selected from a codebook which comprises a plurality of precoding matrixes, and changes the first precoding matrix to a second precoding matrix per predetermined period, and applying the second precoding matrix to the downstream data to transmit the downstream data through the antennas. The second precoding matrix is a precoding matrix corresponding to an index which has been shifted by a certain value from an index of the first precoding matrix in a direction where an index of a precoding matrix increases, in the codebook

The data are communicated from a transmitter to a receiver in a wireless communications network. Data symbols are modulated using a coded modulation to produce modulated symbols and the modulated symbols are precoded using a precoder matrix to produce precoded symbols. The precoder matrix is formed using a rotation matrix including phase angles for at least some elements of the rotation matrix with values determined according to a parametric function of indices of the elements storing the phase angles. Next, the data packets are formed using the precoded symbols and the data packets are transmitted over the wireless network. Multi-stage parametric phase precoding provides full-diversity and full-rate transmissions by using fast-transformable unitary matrices and deterministic diagonal phase rotation, whose phase angles are pre-determined to minimize the union bound for time-selective and frequency-selective fading channels.

A method for transmitting and receiving signals using multi-band Radio Frequencies (RFs) is provided. The method performs channel coding on an information unit of a specific layer above a physical layer to produce a specific number of codewords and maps the generated specific number of codewords to a plurality of frequency allocation bands managed by one specific layer, and then transmits the mapped signal through each of the plurality of frequency allocation bands. Each of the plurality of frequency allocation bands managed by the one specific layer has a band size for allocation for a specific service according to a predetermined frequency policy. When the generated specific number of codewords is mapped to the plurality of frequency allocation bands, each of the specific number of codewords is mapped to at least one of the plurality of frequency allocation bands. A frequency allocation band used for transmission of each codeword when the codeword is retransmitted may be set to be different from that when it is initially transmitted.