342 results about "Transmission diversity" patented technology

A method and apparatus are described for a User Equipment (UE) to transmit in a control channel ACKnowledgement signals associated with a Hybrid Automatic Repeat reQuest process (HARQ-ACK signals) in response to receiving Transport Blocks (TBs) transmitted from a base station. The UE conveys the HARQ-ACK information by selecting one resource from multiple resources in the control channel and by selecting a constellation point of the modulation scheme for the HARQ-ACK signal. Transmission diversity is supported using different control channel resources that are already available to the UE without configuring additional resources. Design principles are described to optimally map the HARQ-ACK information to control channel resources and modulation constellation points for a Time Division Duplex (TDD) system and for a Frequency Division Duplex (FDD) system.

A method for transmitting data via multiple antennas by modulating data to be transmitted into a plurality of modulated symbols, encoding each pair of modulated symbols from among said plurality of symbols in accordance with a transmission diversity scheme to result in a plurality of N by N matrices, with each N by N matrix corresponding to each pair of modulated symbols, generating a M by M code matrix comprised of the plurality of N by N matrices, orthogonally spreading the M by M code matrix to generate an output matrix, generating a plurality of row-permuted matrices by exchanging at least one pair of rows in the output matrix, and transmitting the symbols in the plurality of row-permuted matrices via a plurality of antennas by using either a space time transmission diversity scheme, a space frequency transmission diversity scheme, or a combination of a space time transmission diversity scheme and a space frequency transmission diversity scheme.

A Method and apparatus for selectively applying, by a User Equipment (UE), Frequency Hopping (FH) for a transmission of Uplink Control Information (UCI) signals in a Physical Uplink Control CHannel (PUCCH). The UE applies FH when the UCI is of a first type and does not apply FH when the UCI is of a second type. The UE applies FH when transmission diversity is not applied to the UCI transmission and does not apply FH when transmission diversity is applied to the UCI transmission. UEs operating in a legacy mode do not apply FH to the UCI transmission while UEs operating with additional functionalities may apply FH to the UCI transmission according to the UCI type and the use of transmission diversity.

In a base station which has a plurality of antennas, each of a plurality of comparison circuits operates to compare correlation levels, which are obtained by despreading received signals for a plurality of channels, with each other with respect to the antennas. Each of a plurality of transmission antenna selecting circuits operates to determine from which antenna a transmission signal is to be transmitted for every channel. Each of a plurality of multiplexing circuits operates to multiplex the transmission signals of the individual channels, which are spread, for every antenna. As a result, on the basis of the result of the comparison of the correlation levels with respect to the antennas, a transmission antenna is selected for every channel, and the signals of the channels that are to be transmitted by a given antenna are multiplexed, whereby the base station achieves transmission diversity.

Provided is a mobile cellular communication system or, more particularly, a transmission diversity communication system in which when the number of transmitting antennas is increased, antennas can be calibrated readily and efficiently with power saved without degradation of the characteristic concerning fading. The transmission diversity communication system is a closed-loop transmission diversity communication system. In the transmission diversity communication system, a base station transmits common pilot signals via a plurality of antennas, and a mobile station receives the common pilot signals. The mobile station transmits feedback signals, which are produced through analysis of the common pilot signals, to the base station. The base station controls a downward transmission signal on the basis of the pieces of feedback information. Herein, the plurality of antennas is divided into a plurality of groups. The common pilot signal is transmitted via a reference antenna included in each of the groups. The common pilot signal is alternately transmitted at a low frequency via the other antennas.

A data transmission method for a base station to acquire transmission beam diversity in a wireless communication system is provided. The data transmission method includes selecting at least two transmission beams to be used for data transmission from among multiple transmission beams corresponding to transmission beam information, if receiving the transmission beam information regarding the multiple transmission beams from a terminal, and transmitting data encoded with a predetermined orthogonalization code to the terminal via the selected at least two transmission beams.

In closed-loop transmission diversity, a communication terminal apparatus calculates a phase correcting value for compensating for an effect of phase rotation due to the transmission diversity, using known feedback information, and corrects a received signal on a communication channel based on the phase correcting value, or corrects a channel estimation value based on the phase correcting value.

A closed-loop STTD system extended from an open-loop STTD system adopting four antennas transmission diversity technique and its signal transmitting method are disclosed. The signal transmitting method in a closed-loop space-time transmit diversity (STTD) system having a plurality of transmission antennas, includes: space-time coding symbols to be transmitted; classifying the coded symbols to certain groups; and multiplying different weight values to each transmission symbol group and transmitting them.

A mobile terminal is capable of efficiently performing transmission diversity of a PDSCH and a DPCH without increasing the number of bits of control information to be fed back to a base station and rendering a feedback period longer. A feedback information generating portion determines transmission diversity control information on the PDSCH in response to a switching instruction from a control portion, when receiving first PDSCH data during soft handover, based on a receiving state of a signal of a cell for sending the PDSCH data. In addition, when receiving the last PDSCH data during the soft handover, the feedback information generating portion determines the transmission diversity control information on the DPCH in response to the switching instruction from the control portion based on the receiving state after synthesis of the signal of the cell of an active set.

The present invention relates to a packet data transmission method in an OFDMA system and an apparatus thereof. The present invention provides a user packet data transmission method including generating a RACH burst for channel information estimation, selecting a first antenna among a plurality of antennas, transmitting the RACH burst through the first antenna to a base station, receiving a data transmission acceptance signal from the base station, in response to the RACH burst, transmitting user packet data through the first antenna when receiving a signal indicating that the data transmission is allowed, and selecting a second antenna that is difference from the first antenna and transmitting a RACH burst through the second antenna when receiving a signal indicating that the data transmission is not allowed, and a transmitting apparatus of a mobile station having the plurality of antennas. According to the present invention, the RACH burst and user packet data are transmitted by using a mobile station having a plurality of antennas in an LTE-applied OFDMA system, and therefore data transmission can be performed with a wide bandwidth and high data rate and a deep fading period that may occur during the data transmission can be reduced, thereby preventing call dropping and improving data transmission performance.

The invention relates to the mobile communication field, disclosing a space frequency coding based multi-antenna transmission diversity method and the system thereof. When the number of transmission antenna is over 2, a coding can be accomplished within an OFDM symbol period and meanwhile a diversity gain similar to STTD+CSD can be obtained. The invention uses space frequency coding to obtain the diversity gain and at the same time introduces phase offset in the frequency-domain to obtain extra frequency diversity similar to CSD through the channel of the frequency-domain data. The phase offset satisfies: the frequency-domain data loaded in the sub-carrier wave set used in SFTD on the same antenna possesses the same phase offset and the frequency-domain data loaded between the sub-carrier wave sets possesses different phase offsets. Moreover, the frequency-domain data loaded on the same sub-carrier wave on different antenna in the same antenna stack possesses different phase offsets.

A channel dividing unit of a transmitter divides a transmission signal into a plurality of channels based on channel structure information indicating a method of structuring an MIMO informed from a receiver. An STC unit realizes transmission diversity according to STC processing for each of the channels divided. A channel estimating unit of the receiver estimates a channel gain for transmission and reception of a signal. Based on a result of estimation of the channel gain, a physical configuration of the transmitter, and a physical configuration of the receiver, a transmission-side channel-structure determining unit of the receiver determines a structure of an MIMO channel, and informs channel structure information to the transmitter.

A multi-antenna transmitting entity transmits data to a single- or multi-antenna receiving entity using (1) a steered mode to direct the data transmission toward the receiving entity or (2) a pseudo-random transmit steering (PRTS) mode to randomize the effective channels observed by the data transmission across the subbands. For transmit diversity, the transmitting entity uses different pseudo-random steering vectors across the subbands but the same steering vector across a packet for each subband. The receiving entity does not need to have knowledge of the pseudo-random steering vectors or perform any special processing. For spatial spreading, the transmitting entity uses different pseudo-random steering vectors across the subbands and different steering vectors across the packet for each subband. Only the transmitting and receiving entities know the steering vectors used for data transmission. Other aspects, embodiments, and features are also claimed and disclosed.

The invention relates to a self-adapting switching method of a transmission mode of an LTE (Long Term Evolution) multi-antenna system, and the self-adapting switching method comprises the following steps that: a base station sets an appropriate transmission mode in a self-adapting way for a user by taking the SINR (Signal to Interference plus Noise Ratio), the movement speed and the geographic position of the user as judgment conditions. The self-adapting switching method comprises the following operation steps of: firstly initially determining multiple parameters, namely a polling period needed by transmission mode switching, a mode switching threshold value, a counter threshold value and a user movement speed threshold value; then determining transmitting data of an acquiescent transmission diversity mode; then calculating an SINR value according to CQI (Channel Quality Indicator) fed back by the user, and comparing the SINR value with a predetermined switching threshold; updating corresponding judgment time and triggering time counters; judging whether a mode switching condition is met or not; and switching a current mode into an ideal target mode, or continuously keeping the current mode to carry out data transmission. The self-adapting switching method disclosed by the invention can be used for regulating the mode switching threshold value and the user movement speed threshold value in real time by counting switching times within set time, thereby realizing the effective balance of network transmission efficiency and timeliness in the switching process.

A base station has a first antenna for emitting radio waves at a first tilt angle and a second antenna for emitting radio waves at a second tilt angle different from the first tilt angle. If the antennas have different propagation lengths, a transmission diversity gain is not obtained and interference occurs in an adjacent area. In such a case, when one antenna having a shorter propagation length, which means less interference in the adjacent area, is used for transmission, the throughput of each terminal is increased at the area. For example, a controller changes two antenna transmission to one antenna transmission when the difference between the reception qualities of signals sent from the base station and an adjacent base station adjacent to the base station is smaller than a predetermined reference, the reception qualities being measured at the terminal.

An apparatus for transmitting data in a wireless communication system is provided. The apparatus includes a data processor for generating modulation symbols by coding information bits and by constellation-mapping the coded information bits, a transmission (TX) processor for generating transmission symbols by applying any one of first and second transmission diversity schemes to the modulation symbols and for configuring a subframe including the transmission symbols, and a plurality of antennas for transmitting the subframe. The subframe comprises a plurality of slots and has a varying frequency band every slot by frequency hopping.