37 results about "Diversity coding" patented technology

Maximum diversity in multiple antenna distributed frequency broadband systems such as MIMO-OFDM is achievable through space-frequency (SF) and space-time-frequency (STF) coding. Full-rate full-diversity coding is achieved through a combination of maximal minimum product distance symbol set design and formation of codeword blocks. Full-diversity codes are also achieved which have reduced symbol transmission rates, such as through mapping of space-time (ST) codes to SF codes. The reduction in symbol rate may be offset by the fact that any ST code may be mapped to a full-diversity SF code.

Maximum diversity in multiple antenna distributed frequency broadband systems such as MIMO-OFDM is achievable through space-frequency (SF) and space-time-frequency (STF) coding. Full-rate full-diversity coding is achieved through a combination of maximal minimum product distance symbol set design and formation of codeword blocks. Full-diversity codes are also achieved which have reduced symbol transmission rates, such as through mapping of space-time (ST) codes to SF codes. The reduction in symbol rate may be offset by the fact that any ST code may be mapped to a full-diversity SF code.

Good transmission characteristics are achieved in the presence of fading with a transmitter that employs a trellis coder followed by a block coder. Correspondingly, the receiver comprises a Viterbi decoder followed by a block decoder. Advantageously, the block coder and decoder employ time-space diversity coding which, illustratively, employs two transmitter antennas and one receiver antenna.

A communication system transmits and receives a plurality of spread-spectrum signals having differences in at least one diversity parameter. The signals are highly correlated when their diversity parameters are similar, and the signals are uncorrelated when at least one diversity parameter is different Any combination of a transmitter, a receiver, and a communication channel may diversity-encode the signals to effect differences in their diversity parameters. A receiver diversity-decoder compensates for differences in a diversity-parameter of at least one received signal to make the signal highly correlated with at least one other received signal. A correlator combines at least two of the received signals to recover an embedded information signal. The communication system enables the use of true-noise signals for spreading information signals, provides simplified receiver designs, and enables antenna arrays to spatially process spread-spectrum signals.

A wireless communication network is configured to provide distributed diversity transmissions, wherein different diversity-coded versions of the same information signal are transmitted from each of two or more network sectors. The diversity-coded versions of the information signal are based on space-time or space-frequency codes, and the information signal may comprise a dedicated channel signal targeted to an individual user or a broadcast signal targeted to one or more users. Thus, spaced-apart network transmitters, which may be located at the same cell site, or at different cell sites, are configured to transmit diversity-coded versions of a given information signal and, in this manner, the advantages of space-time and / or space frequency transmission coding may be applied across multiple sectors of a communication network. Such transmissions may be used to improve soft and softer handoff reception of dedicated channel signals, and to improve reception of Broadcast-Multicast Services (BCMCS) signals, or the like.

Briefly, an apparatus and method to transmit data stream by using a multiple-input-multiple-output (MIMO) transmitters receivers system. The MIMO transmitters receivers system may include a coding mode selector to select a coding mode of each orthogonal frequency division multiplexing (OFDM) sub-carrier symbol of a first and second sub-carriers of a data stream according to a feedback data packet having coding information of the OFDM subcarrier symbol. The coding mode may be selected from a diversity coding mode and a multiplexing coding mode.

A system and method of processing frequency-diversity coded signals with a low sampling rate less than the Nyquist rate for ultra-wideband devices are described. The frequency-diversity coding system comprises a frequency-diversity encoder, one or more first transformation device, a summation device, a signal filter, a sampling device, a second transformation device and a frequency-diversity decoder. The frequency-diversity encoder encodes a plurality of information blocks to output matrix elements. The first transformation devices convert the matrix elements into a plurality of OFDM symbols. The summation device superposes a plurality of frequency bands to generate a transmitted signal. The signal filter eliminates noise in the received signal. The signal filter comprises a low-pass filter for removing the noise in the received signal. The sampling device coupled to the signal filter samples the received signal by a sampling rate less than a Nyquist rate. The sampling rate is equal to the bandwidth of one subcarrier of the OFDM symbols. Additionally, the frequency-diversity decoder coupled to the second transformation device interprets the received signal to decode the information blocks.

The invention relates to a time-frequency joint channel estimation method of time-domain synchronous orthogonal frequency division multiplexing (TDS-OFDM) space-frequency coding, which belongs to the technical field of digital information transmission. The steps are: 1) transmit antennas T1 and T2 to perform space-frequency diversity coding; 2) alternately transmit transmission parameter signaling (TPS) information carried on OFDM subcarriers on T1 and T2 according to certain rules; 3) Time-frequency joint channel estimation is performed by using time-domain PN sequence and frequency-domain TPS information; 4) Sending information is recovered through space-frequency decoding. The transmission space-frequency coding time-frequency joint channel estimation method described in the present invention hardly changes the original transmitter system, the processing method is simple, fast and accurate, maintains the transmission efficiency of the system, and supports "soft failure", increasing reliability . At the same time, the present invention does not lose its generality, and can be easily transplanted to other multi-carrier terrestrial digital television broadcasting systems.

The invention provides a multi-antenna emission diversity method, which includes steps of carrying out diversity coding for conversion symbol obtained by carrying out coding modulation and conversion to the data to be sent, mapping the data on corresponding time space frequency resource and sending. The diversity coding comprises carrying out time space coding and phase rotation to conversion symbol to obtain diversity coding block, and is characterized in that in a same diversity coding block, phase rotation values of a same column are same, phase rotation values of different columns are incomplete same, and phase rotation values of at least a pair of corresponding positions in phase rotation values of corresponding position between at least one diversity coding block and other diversity coding blocks. The invention also provides a multi-antenna emission diversity device. The method and the device of the present invention obtain diversity gain brought by different signal passing through differential channel, thereby increasing diversity gain.

Good transmission characteristics are achieved in the presence of fading with a transmitter that employs a trellis coder followed by a block coder. Correspondingly, the receiver comprises a Viterbi decoder followed by a block decoder. Advantageously, the block coder and decoder employ time-space diversity coding which, illustratively, employs two transmitter antennas and one receiver antenna.

A wireless communication network is configured to provide distributed diversity transmissions, wherein different diversity-coded versions of the same information signal are transmitted from each of two or more network sectors. The diversity-coded versions of the information signal are based on space-time or space-frequency codes, and the information signal may comprise a dedicated channel signal targeted to an individual user or a broadcast signal targeted to one or more users. Thus, spaced-apart network transmitters, which may be located at the same cell site, or at different cell sites, are configured to transmit diversity-coded versions of a given information signal and, in this manner, the advantages of space-time and / or space frequency transmission coding may be applied across multiple sectors of a communication network. Such transmissions may be used to improve soft and softer handoff reception of dedicated channel signals, and to improve reception of Broadcast-Multicast Services (BCMCS) signals, or the like.

The invention discloses a visible light communication method, which comprises the steps of: at a transmitting end, subjecting a data stream to OFDM coding based on space diversity coding, modulating OFDM codes to obtain a visible light signal by means of a single LED light source, and transmitting the visible light signal; at a receiving end, converting the received visible light signal into an analog electric signal by means of a single photodiode, converting the analog electric signal into a digital signal, demodulating the digital signal by means of OFDM data symbols to obtain OFDM data symbols, demodulating the OFDM data symbols based on space diversity coding, and restoring the original data stream. The visible light communication method fully utilizes the technical features of the signal space diversity coding, encodes real portions and virtual portions of transmitted signals so that the real portions and virtual portions are independent from each other, realizes the purpose of forming a diversity effect by just using a single receiver for receiving in a multi-path interference environment, effectively improves the transmission capability of signals in a frequency selective fading channel, improves the adaptability of a visible light communication system and enhances the system performance integrally.

In one aspect, a method to enhance coverage in a heterogeneous wireless network wireless communication is disclosed. The method includes generating a reference signal indicating a plurality of transmit antenna ports and generating modulation symbols. Modulation symbols are assigned to each of the plurality of transmit antenna ports, in accordance with a spatial diversity coding scheme for the plurality of transmit antenna ports. At least one of the modulation symbols assigned to at least one of the plurality of transmit antenna ports is muted prior to transmission in accordance with the spatial diversity coding scheme. The non-muted modulation symbols and the reference signal are transmitted on the other of the plurality of transmit antenna ports.

The invention relates to a cooperative diversity positioning method based on a satellite positioning system. A space-time cooperative diversity positioning scheme based on an Alamouti code and MIMO-spread spectrum space diversity coding are designed according to the satellite positioning system. The method concretely comprises the steps that according to space-time cooperative diversity positioning based on the Alamouti code, adjacent satellites in the same track are grouped into satellite pairs so that adjacent satellite cooperative diversity is realized; and cooperative diversity MIMO-spread spectrum space diversity coding aiming at the satellite positioning system is designed based on an MIMO-direct sequence spread spectrum method multi-code model. Compared with methods in the prior art, the method has superiorities that signal gain is enhanced without increasing positioning signal transmitting power so that the service life of the satellites can be effectively prolonged under the premise of guaranteeing anti-interference capability; and cooperative diversity of the adjacent satellites closely combines the positioning satellite constellation characteristics, and robustness of positioning signals is enhanced without changing a space segment structure function or increasing extra burden of the satellites.

Disclosed is a four-antenna diversity transmitting device based on a GMC system, a transmitting method and a receiving device and a receiving method. In the transmitting device, a shaping filter pack module divides the whole channel bandwidth intp a plurality of orthogonal sub-channels, and each sub-channel is corresponding to a subfilter, then each pixel symbol in the column vector of the signalis respectively mapped onto the corresponding sub-channel, and then a multi-antenna diversity coding module converts the parallel symbol data sequence into the similar Alamouti structure and the signal pack with the diversity degree 4, finally four antennas are adopted to transmit the signal pack in eight block time, while in the receiving device, the minimum mean-squared error is adopted to balance the received signal, then the signal sequence is processed with the sub-belt matching filter, to generate the symbol data sequence of outputting a plurality of sub-belts in parallel, thereby obtaining the full diversity gain and effectively ensuring the communication quality of the chain, also realizing the peak-to-average power ratio and the reduction of the carrier frequency deviation error suseptibility.