45results about "Multi-frequency code systems" patented technology

An OFDM receiver includes an offset compensator (14) compensating for a frequency offset in a received OFDM signal. The offset compensator (14) includes a memory (51) storing two reference signals corresponding to arbitrary portions in the start symbol of the OFDM signal. A cross correlation value between the received OFDM signal and each of the two reference signals is calculated by a cross correlator (52, 53). Each peak position is detected by a peak detector (54). A frequency offset estimate value of the received OFDM signal is estimated by a frequency offset estimation circuit (55) based on the cross correlation value at each detected peak position. A phase rotation circuit (37) compensates for the frequency offset of the received OFDM signal based on the estimated frequency offset estimate value.

The invention relates to a mapping device of a physical communication channel in an orthogonal frequency-division multiplexing system and a mapping method thereof, wherein the method implements the following steps to each flow of symbols which is generated after a code clock in a transmission block is processed, firstly orderly dividing the flow of symbols into a plurality of resource block transmission units with the resource block transmission length, secondly, determining the mapping area which integrates the resource blocks which are corresponding to the flows of symbols and the quality indicated value of the communication channels which are respectively corresponding to the resource blocks in the area, thirdly, mapping the resource transmission block unit which is near to the front most position of the unmapped position into the resource block whose indicated value of the unmapped communication channel quality is the biggest. The method improves the decrypting accuracy of a terminal and reduces the retransmitting frequency through mapping the RB transmission unit whose position is near to the front position in the flow of signals into the RB with higher CQI value.

The invention provides a method aiming at the overall consideration and complexity of an uplink in a synergetic OFDM (orthogonal frequency division multiplexing) system for the resource allocation in a synergetic OFDM system. The method is characterized in that relays with the number thereof being a positive integer are arranged between a subscriber and a base station and each relay is provided with a plurality of subcarriers with the number being identical with that of the relays. The method comprises the following steps: firstly, the base station selects a relay according to the minimum equivalent signal-to-noise ratios of the subcarriers in each relay, that is, the base station selects the relay with the maximal equivalent signal-to-noise ratio of the subcarriers from the relays with the minimal equivalent signal-to-noise ratio of the subcarriers as the relay node for the subsequent synergetic transmission; then, the selected relay sequences the subcarriers between the subscriber and the selected relay and between the subscriber and the base station sequentially pair the subcarriers, namely, the subcarriers of the relay with high signal-to-noise ratio are used for transmitting the data supposed to be transmitted by the subcarriers of the subscriber with high signal-to-noise ratio; and finally, the base station carries out the water-filling power allocation on each intra-subcarrier according to the equivalent channel gain of each subcarrier pair, and starts the synergetic transmission.

CSIT error considerate delay-sensitive user access systems are provided in a multi-user OFDMA environment comprises a user delay sensitivity tracking component, a CSIT estimating component, a system queue state tracking component and a cross layer scheduling component. The techniques assume heterogeneous users with respect to delay and assume that CSIT information includes error, and optimally allocates broadcast resources, e.g., power, subcarriers and data rate, based on such assumptions.

A method for setting transmission grant of a MIMO UE in a network of a wireless communications system for uplink transmission is disclosed. The method includes sending at least one control or configuration message corresponding to each HARQ entity of at least one HARQ entity or at least one HARQ process of an HARQ entity to the UE to set transmission grant of the UE when the UE performs uplink transmission through the at least one HARQ entity or the at least one HARQ process of the HARQ entity.

The normalized iterative soft interference cancellation signal detection method relates to a signal detection method of multiaerial wireless communication system iterative receiver. Said detection method is characterized by that it makes the received multiaerial signal undergo the processes of interative detection, decoding and receiving treatment based on iterative soft interference cancellation detection. Said invention also provides the equipment for implementing said detection method.

The invention discloses the transmitting and receiving method for mobile digital multimedia broadcast physical layer signaling message. Wherein, the transmission method comprises: mapping the signaling message on the idle data sub-carrier or both the continual pilot frequency and idle data sub-carrier, and modulating former sub-carrier or both continual pilot frequency and sub-carrier in OFDM signal for transmitting. The receiving method comprises: receiving OFDM signal to demodulate the idle data sub-carrier or both the idle data sub-carrier and continual pilot frequency; hereby, obtaining the signaling message. This invention improves transmission efficiency, saves system resource, and reduces decoding complexity.

A method in which a first apparatus performs wireless communication and an apparatus supporting the same are provided. The method may include: receiving information related to a physical sidelink feedback channel (PSFCH) resource from a base station; receiving a physical sidelink shared channel (PSSCH) from a second apparatus; and transmitting a PSFCH related to the PSSCH to the second apparatus. Here, the information related to the PSFCH resource may include, for example, information related to a resource block (RB) available for the first apparatus to transmit the PSFCH.

The present invention relates to a method for defining, in a TDD wireless communication system in which broadband is configured by means of carrier aggregation, transceiving timing for a data channel and a control channel when cross-carrier scheduling is implemented.

The invention discloses a sub-frame distribution system and a method. The sub-frame distribution system comprises: a parameter acquisition unit used for acquiring the system parameter of a communication system; a sub-frame dividing unit used for dividing each data frame of the communication system into a plurality of sub-frames according to the system parameter; and a sub-frame distributing unit used for respectively distributing sub-frames dedicated to down business to the down business and sub-frames dedicated to up business to the up business according to the requirements of the down and the up businesses of the communication system. Through the invention, the feedback time delay of the system can be decreased, thus meeting the business requirements of high-speed mobile users.

The invention discloses a system information sending and receiving method and device in a digital audio broadcasting system. The method comprises the following steps of: when in sending, performing CRC (cyclic redundancy check) coding and channel coding on the system information to generate a coding bit stream; performing bit interleaving and constellation mapping on the coding bit stream to obtain a continuous pilot frequency including the system information; multiplexing a continuous pilot frequency signal with other signal elements of the system to obtain a frequency-domain signal of an orthogonal multiplexing structure according to a carrier allocation method stipulated by a frequency spectrum mode; converting the frequency-domain signal into a time-domain signal for sending; when in receiving, converting the time-domain signal into a frequency-domain signal; extracting the continuous pilot frequency including the system information from an effective carrier of the frequency-domain signal according to the position stipulated by the frequency spectrum mode; obtaining an estimated value of the system information through de-mapping, de-interleaving and channel decoding; and judging the correctness of the system information by use of CRC decoding, and outputting the system information. The method and device disclosed by the invention can improve the transmission robustness on the basis of guaranteeing the transmission efficiency of the system information.

The invention discloses a method and a device for configuring types of cyclic prefixes. The method comprises the step of sending configuration information used for indicating types of uplink cyclic prefixes to different terminals by a base station, wherein the types of uplink cyclic prefixes are at least divided into a first-type uplink cyclic prefix and a second-type uplink cyclic prefix according to the length of a time domain; the different terminals comprise at least two types of terminals, and/or terminals of at least two types of services; and a sub-frame/wireless frame set of the first-type and/or the second-type uplink cyclic prefix configured for one type of terminal or service is a sub-set of a sub-frame/wireless frame set of the same type of uplink cyclic prefix configured for another type of terminal or service. By adopting the method and the device provided by the invention, the problem in the related art that the utilization rate of uplink resources is relatively low is solved, and the utilization rate of the uplink resources is improved.

The invention discloses a symbol synchronization method of a visible light DCO-OFDM communication system. The method comprises steps: a transmitter generates a mirror-symmetrical preamble sequence; the transmitter puts the preamble sequence into the head of each DCO-OFDM symbol, And transmit to the receiver; the receiver calculates the timing metric according to the received signal; performs timing according to the timing metric, obtains the starting position of the symbol, and realizes symbol synchronization. The symbol synchronization accuracy of the present invention is higher.

The invention provides an uplink system of a subcarrier multiplexing optical network of filter based multicarrier modulation. The system comprises access control modules, filter based multicarrier modulation modules, subcarrier modulation modules, a multiplexing module, a feed line type fiber, a de-multiplexing module, photoelectric detectors, subcarrier demodulation modules and uplink data reception modules that are successively connected. Data generated by the access control modules is modulated in the filter based multicarrier modulation method, modulated user data is modulated to different optical subcarriers and transmitted via RF subcarrier modulation of optical carrier waves, and data from different units is multiplexed to uplink fiber channels. Filter based multicarrier modulation technology is combined with subcarrier multiplexing technology so that frequency spectrum resources of uplinks are utilized in high efficiency, interference among symbols and subcarriers of uplink users can be effectively resisted, and higher transmission speed and frequency spectrum frequency can be supported.

A flexible Fast Walsh Transform circuit provides configurable FWT sizes, and is suitable for use in radio receivers where the received signal may be generated using varying spreading codes and/or varying numbers of multi-codes. Such signal types are commonly encountered in wireless communication systems like those based on the Wideband CDMA (W-CDMA) or IS-2000 (cdma2000) standards, and particularly with the higher data rate provisions of those standards. In one application, a RAKE receiver includes RAKE fingers that each include one of the flexible FWT circuits, such that each finger despreads the received signal using variably sized FWTs in accordance with the characteristics of the received signal. The flexibility in FWT sizing may derive from, for example, the inclusion of separately selectable but differently sized FWT circuits, or from the inclusion of a configurable FWT circuit capable of generating different sizes of FWTs.

A receiving station apparatus controls a number of null carriers included in a transmission signal transmitted by a transmitting station apparatus in a communication system adopting a multicarrier modulation system to suppress inter-carrier interference by using the null carrier. For example, a reception-quality measuring unit measures a reception quality of a subcarrier group forming the transmission signal, and a number-of-null carriers determining unit determines the number of null carriers included in a next transmission signal based on the reception quality.

The invention relates to a blind estimation method for the signal to noise ratio of an OFDM system, and belongs to the technical field of wireless communication. Data subcarrier mean power and virtual carrier mean power are obtained on the basis of preambles of signal frames of the OFDM system, and further the signal to noise ratio is determined. Thus, the communication efficiency is higher compared with a pilot-aided estimation method for the signal to noise ratio in the prior art; the estimation precision is higher compared with a signal to noise ratio estimation method in which virtual carriers are used, and the blind estimation method of the invention is low in complexity, easy to realize and low in realization cost.

A method of transmitting demodulation reference signals (DMRS) over one, three or five resource blocks (RBs) with Interleaved Frequency Division Multiple Access (IFDMA) from a wireless device to a wireless network node in a wireless network wherein Single Carrier Frequency Division Multiple Access (SC-OFDMA) is deployed in uplink, is provided. At least one of: a set of base sequences including thirty quadrature phase shifting keying, QPSK, sequences of length 6, 18 or 30 is determined, a demodulation reference signal sequence is derived from the determined set of base sequences, the demodulation reference signal sequence is multiplexed, and the multiplexed demodulation reference signal sequence is transmitted, by the wireless device, to the wireless network node.

Methods and apparatuses disclosed herein enable the use of Demodulation Reference Signal, DMRS, sequences that are numbered relative to an overall system bandwidth (30), while simultaneously enablingwireless communication devices (12) to determine the DRMS sequence elements mapped to their scheduled bandwidths (36) within the system bandwidth (30). Advantageously, the wireless communication devices (12) need not know the system bandwidth (30), or even be aware of where their scheduled bandwidths (36) reside within the system bandwidth (30).

The invention relates to the field of signal processing, and specifically relates to a peak power determining method, a peak-to-average power ratio determining method, a peak power determining device, and a peak-to-average power ratio determining device. The peak power determining method comprises the following steps: getting the sampling power at the current sampling time; comparing the sampling power at the current sampling time with the estimated peak power at the current sampling time; and when the sampling power at the current sampling time is higher than the estimated peak power at the current sampling time, determining the sampling power at the current sampling time as the actual peak power at the current sampling time. According to the invention, the efficiency of peak power detection is improved, and the peak power can be determined in real time at each sampling time.

The invention provides a method of communication parameter detection and a related device. The method and the related device are used for detecting the length of protection time intervals of message loops in communication signals. The method includes the steps of searching peak values in self-relevant signals of the communication signals, providing the peak values for the message loops, classifying time difference between the two adjacent peak values into one of a plurality of intervals of histogram statistics, deciding the length of the protection time intervals according to results of the histogram statistics, finding a peak value, providing a signal average according to an average in average value statistics of the self-relevant signals, comparing a ratio between the peak values and the signal average, and judging whether the ratio is larger than a critical value. Accordingly, whether effective information is carried in the communication signals can be detected.

An audio data transmitting device with a varying channel count which on the transmission side includes, data of n channels divided into blocks each defined for m channels where n≦m. In addition, prior to a transmission of the audio data, a transmitted-data stream matching a predetermined transmission format is generated to include determination information used for determining which portions of each block is allocated to which portions of each block containing no valid data. On the reception side, the determination information included in the received transmitted-data stream matching the predetermined transmission format is used to identify the unused channels not assigned to valid data in each of the blocks composing the transmitted-data stream which allows data of the valid channels to be extracted from the stream.

The invention discloses a joint sidelobe suppression method and a joint sidelobe suppression device based on bipolar coding and windowing. Baseband data generated by a digital information source module are coded by a channel of a channel coding module; after being subjected to serial-to-parallel conversion of a modulation mapping and serial-to-parallel conversion module of a modulation mapping module, the baseband data are sent into a bipolar coding module; the bipolar coding module carries out bipolar coding on parallel data in sequence and then sends the parallel data into an IFFT transformation module for IFFT transformation; the data subjected to the IFFT transformation are sent into a parallel-to-serial conversion module for parallel-to-serial conversion after passing through a raised cosine window of a windowing module and are then sent into a radio frequency module to form a final OFDM modulation signal. According to the method, the sidelobe suppression performance can be improved under the conditions that the calculation complexity is not increased and interference is not introduced, so that the interference of a cognitive user on a main user is suppressed to the maximum extent.

The invention discloses a data transmission method based on OFDM, which is used for uplink data transmission in a short-to-middle-distance wireless communication system. The available frequency band of the system is divided into N basic frequency sub-bands in advance. The method includes: the transmitting site occupies M basic frequency sub-bands Frequency band, modulate the data to the M basic sub-bands and send it out; the receiving station receives the data sent from one or more transmitting sites within the N basic sub-bands; M≤N, M and N are both positive integer. The invention also provides an OFDM-based data transmission system. The present invention is based on the combination of OFDM technology and sub-frequency bands, allowing the transmitting site and receiving site in the wireless communication system to have different bandwidth configurations, the transmitting site can use a lower configuration to reduce hardware costs, and the receiving site can use a higher configuration to improve bandwidth. Efficiency: Spectrum utilization, throughput, etc., and enables multiple user sites to communicate with access points at the same time.