87 results about "Diversity effect" patented technology

A method is provided for transmitting data, which improves a diversity effect in a communication system. The method includes transmitting an information word including a codeword in a (k+s)-th frame, generating s groups based on parity bits obtained by encoding the information word, and transmitting the s groups in s frames preceding the (k+s)-th frame, in a distributed manner.

The circuit size of a diversity receiver for an orthogonal frequency division multiplexing signal is reduced, and the diversity effect is increased, by providing a power ratio comparator that calculates a difference value as a ratio of powers derived from channel estimation results for subcarrier components received from two antennas (11), (21) and compares the calculated difference value with a predetermined threshold, and a selective/equal gain combining selector (33) that outputs one of the received demodulated signals when the comparison result indicates that the calculated difference value is greater than the threshold value.

A communication technology for allowing a mobile communication system to accommodate variable rate users, while obtaining a frequency diversity effect. A transmitter apparatus using, for transmission, transmission signals produced based on data symbols of a predetermined transmission method, comprising an FFT processing part for converting the data symbols to frequency domain data; an interleaver for sorting the frequency domain data; and an IFFT processing part for converting the sorted frequency domain data to a time domain signal; wherein the FFT processing part subjects Q received data symbols to Q-point FFT processing, the interleaver produces N data from Q data outputted from the FFT processing part (where N>Q), and the IFFT processing part subjects the N data outputted from the interleaver to N-point IFFT processing.

An apparatus for transmitting and receiving a signal in Code Division Multiple Access/Orthogonal Frequency Division Multiplexing (CDMA/OFDM) system is provided. The apparatus discriminates user signals with a unique spreading code and the orthogonal codes, increases data transmission rate with the non-binary value without increasing of entire bandwidth used by the users, solves signal interference with interleaver and diversity effect of interleaving and OFDM, and maximizes transmission efficiency by varying modulation schemes depending on channel states.

It is possible to obtain the diversity effect in a plurality of slots while preventing complication of a scheduler or inefficient use of resources, to eliminate the phenomenon in which SINR significantly decreases in a specific slot, and to avoid deterioration of demodulation performance. In a radio communication system which performs transmission in a sub-frame unit having two slots temporally continuously arranged, when pre-coding is performed by multiplying a signal to be output to a plurality of antennas by a pre-coding weight, CDD is used to shift a phase such that the phase in the pre-coding weight is cyclically changed on the frequency axis. The phase shift amount to be applied by the CDD is set to change by 2π in an allocated resource block (1RB) of the local device, and PVS is applied such that the phase shift amount differs by π between the weight W0 of the first half slot and the weight W1 of the second half slot in the sub-frame.

The division method for channel resource in a wireless communication system comprises: pre-dividing some resource from system physical time-frequency source to carry at least one distributed physical resource unit for distributed transmission, setting the number as n; dividing the residual resource into (N-n) local physical resource units for local distributed transmission; and mapping the distributed/local virtual resource block to the distributed/local physical resource unit, respectively. This invention can provide well frequency diversity effect, and affects little to local transmission user.

A wireless transmission device enabled to improve an error rate performance at a receiver, by acquiring at least one of frequency diversity effect and a time diversity effect while keeping the interference resistance which is acquired by diffusion. In this transmission device, a modulation unit (101) modulates data to create a modulation symbol having in-phase components and quadrature components. An IQ individual spreading unit (102) arranges the diffusion chips, which are obtained by spreading the modulation symbol, of the in-phase components and the quadrature components, in areas extending in diffusion domains set individually for the in-phase components and the quadrature components. An IQ combining unit (103) combines the arranged spreading chips of the in-phase components and the quadrature components.

A method is provided for transmitting data, which improves a diversity effect in a communication system. The method includes transmitting an information word including a codeword in a (k+s)-th frame, generating s groups based on parity bits obtained by encoding the information word, and transmitting the s groups in s frames preceding the (k+s)-th frame, in a distributed manner.

The invention relates to a wireless communication system, which discloses a multi-antenna system and a data transmitting method. In the invention, the plural phase sequence in the MIMO precoding system of CDD is improved, to cause the phase shift in the whole system bandwidth equal to CDD, meanwhile the variable step of the plural phase sequence is set to be equal to the corresponding sub-carrier of the precoding feedback bandwidth, thereby keeping higher precoding performance when the feedback bandwidth is greater relative to the whole frequency band ratio. The virtual cycle time delay can be changed along the time, thereby obtaining the diversity effect on the time. When the channel frequency has small selectivity, the virtual cycle time delay makes the minimum to obtain the dispatching gain.

The invention discloses a method for mapping control channel sources. The method comprises the following steps: confirming the number of source element groups occupied by a physical control format indicator channel (PCFICH) and a physical hybrid automatic repeat request indicator channel (PHICH) and the total number of the source element groups supported by a system; confirming a number NREG of the source element groups occupied by a physical downlink control channel (PDCCH) according to the confirmed total number and the number of the source element groups occupied by the PCFICH and the PHICH; expanding a complex value 4-tuple sequence of the PDCCH according to the NREG to obtain an expanded 4-tuple sequence; mapping the expanded 4-tuple sequence into a matrix according to a first preset mode; permuting the columns of the matrix to obtain a permutation matrix; reading the permutation matrix in a second preset mode to obtain a new 4-tuple sequence; and mapping the new 4-tuple sequence to the source element groups by a time priority principle. The invention also discloses a device for mapping the control channel sources. The invention can reduce the mutual interference among the control channels and improve the diversity effect of an OFDM technology.

The invention discloses a resource mapping method of a control channel in an orthogonal frequency division multiplexing system. The method comprises the following steps of: (1) dividing a wireless channel resource into a logic resource and a physical resource of which the total numbers are both N, coding the resources as L = l1, l2, ellipsis and lN, and P = p1, p2, ellipsis and pN respectively, and coding an OFDM SYMB of the wireless channel as 0, 1, ellipsis and N-1; (2) determining a frequency hopping function f (L), and obtaining offset v shift corresponding to the OFDM SYMB according to a formula v shift = ((NSC/n).(mod (NID, n* NRB)))/(2*m); (3) allocating the logical resource for PCFICH, and mapping the logical resource to the physical resource; and (4) allocating the logical resource when a vacant logic resource is PHICH and PDCCH in sequence, and mapping both logic resources to the physical resource according to a mapping function P = mod (f (L) +v shift, N). The method ensures that logically adjacent control channels with the same type in the same cell keep a distance as far as possible in a frequency domain, and the same control channel of the adjacent cells keeps a distance as far as possible in the frequency domain, reduces the interference among all the control channels, and improves the diversity effect of the OFDM technology.

Provided is a relay transmission method capable of obtaining the diversity effect even when a relay station has detected an error in a relay signal when performing communication between a base station and a mobile station via a relay station. In the relay station used in this method, a decoding unit (104) performs error-correction-decoding of a systematic bit by performing repeated decoding such as a turbo decoding by using a parity bit and obtains a decoding result formed by a systematic bit after the error-correction-decoding. An error judging unit (105) judges whether the decoded result has an error by using CRC (Cyclic Redundancy Check). An encoding unit (106) performs error-correction-encoding of the decoded result and obtains a systematic bit after error-corrected-encoded and a parity bit. A selection unit (107) selects the decoded result inputted from the decoding unit (104) or the bit string inputted from the encoding unit (106) according to the judgment result obtained by the error judging unit (105) and outputs it to a modulation unit (108).

Transmission data in a different interleaving pattern is input for each retransmission via interleaver 31 to outer coding processing section 32 that performs coding processing with a strong correction capability for the burst error such as Reed-Solomon coding. Inner coding processing section 33 performs coding processing with a strong correction capability for the random error such as turbo coding. Different outer code parity bits are thus transmitted for each retransmission, and the decoding side is capable of performing outer code decoding processing using different outer code parity bits corresponding to the number of retransmissions, and thus improves the correction capability for the burst error. As a result, it is possible to acquire both the combining gain due to the inner coding processing and the diversity effect due to the outer code by retransmission, and it is thus possible to effectively reduce both the random error and burst error while taking full advantage of retransmission.

Provided is a radio communication base station device capable of acquiring both a multi-user diversity effect and a frequency diversity effect simultaneously in multi-carrier communications. In this devices modulation units (101-1 to 101-n) modulate data to mobile stations (MS#1 to MS#n) individually to create data symbols. A separation unit (102) separates each data symbol inputted, into an Ich (in-phase components) and a Qch (orthogonal components). An Ich arrangement unit (103) and a Qch arrangement unit (104) arrange the Ich and Qch, respectively, in a plurality of sub-carriers constituting an OFDM symbols, and output the same to a synthesization unit (105). This synthesization unit (105) synthesizes the Ich and Qch arranged for each sub-carrier, to create the synthesized symbol.

The invention discloses a passive time reversal underwater sound communication method suitable for a mobile platform, wherein at least a receiver or a sender moves, the same information frame is repeatedly emitted on different position points, and channel transfer functions on different position points have lower correlation. A receiving end carries out pretreatment, such as frame synchronization, time reversal convolution, Doppler correction and the like, to a received signal, then merges a plurality of pretreated signals received on different opposite positions, and recovers emission information by operations, such as symbol synchronization, spread spectrum sequence correlation and the like. The invention has the beneficial effects that level correlation of a underwater sound communication channel is weakened by using position changes to provide a space diversity effect for time reversal treatment; the configuration of the time reversal communication system is lowered, and for the minimum configuration, the receiving end and the sending end are needed to be provided with only one real object array element respectively. Meanwhile, the same information frame is repeatedly emitted at different time points to obtain the time diversity effect, thereby obviously improving the reliability of the underwater sound communication system in the complex environment.

The invention relates to an antenna unit which comprises a basal plate, a first grounding part, a second grounding part, a first radiation part and a second radiation part, wherein the basal plate is provided with a surface, a grounding face formed on the surface as well as a first feed-in point and a second feed-in part which are formed on the surface; the first grounding part extends outwards from a first end of the grounding face; the shape of the second grounding part is similar to that of the first grounding part, and the second grounding part extends towards a direction opposite to the first grounding part from the first end of the grounding face. The invention can achieve a diversity effect by the first grounding part and the first radiation part as well as the second grounding part and the second radiation part, thereby being capable of reducing the situation of a bad signal caused by the multi-path effect to a large extent and increasing the effectiveness of the whole antenna.

The present invention aims to provide a user selection method which can provide a large, multiuser diversity effect with a small amount of calculation in multiuser MIMO systems, the method being a user selection method for multiuser MIMO communication, in which an orthogonal coefficient is calculated using a received SINR from a projection channel vector by using GS orthogonalization, and using the orthogonal coefficient, a correction SINR is calculated, and using this correction SINR, user selection is performed, and for a next user selection, the projection channel vector is updated, and the above processes are applied to all users.

The invention discloses a method for open-loop MIMO (multi-input multi-output) transmission on the basis of a demodulation reference signal. The method includes the steps of mapping data to be transmitted in every level to a DMRS (demodulation reference signal) port via a first weight value according to regulations set by both a transmitter and a receiver, mapping DMRS port data to a CSI-RS (channel state information-reference signal) port or a physical antenna via a second weight value, and transmitting. The invention further discloses a device for the open-loop MIMO transmission on the basis of the demodulation reference signal. The limit that a same PRB (physical resource block) must utilize an identical precoding weight value is avoided, and larger diversity gain can be obtained. The characteristics that direction information in a communication system evolves slowly and phase information in different polarizing directions evolves quickly is fully utilized. In addition, on different PRB or frequency bands, different second weight values can be utilized to realize the mapping from the DMRS port to the CSI-RS port, and thereby diversity effect is further improved.