558 results about "Channel sounding" patented technology

A method of modulating communications signals, such as optical fiber, wired electronic, or wireless signals in a manner that facilitates automatic correction for the signal distortion effects of echoes and frequency shifts, while still allowing high rates of data transmission. Data symbols intended for transmission are distributed into N×N matrices, and used to weigh or modulate a family of cyclically time shifted and cyclically frequency shifted waveforms. Although these waveforms may then be distorted during transmission, their basic cyclic time and frequency repeating structure facilitates use of improved receivers with deconvolution devices that can utilize the repeating patterns to correct for these distortions. The various waveforms may be sent in N time blocks at various time spacing and frequency spacing combinations in a manner that can allow interleaving of blocks from different transmitters. Applications to channel sounding / characterization, system optimization, and also radar are also discussed.

In a wireless communication system, a method and apparatus for closed loop transmission is disclosed. In accordance with the preferred embodiment of the present invention, a time frequency portion of an uplink frame is dynamically reserved as a sounding zone for uplink channel sounding. A first message is transmitted to a first subscriber station in a downlink frame assigning a time-frequency resource within the sounding zone, and a sounding waveform. Furthermore, a signal is received from the subscriber station within the assigned time-frequency resource, a partial channel response is determined from the received sounding signal, and the subsequent transmission to the subscriber station is tailored based on the at least partial channel response.

A method for channel sounding by an access point includes transmitting a sounding frame to a plurality of mobile stations (STAs). The sounding frame includes training symbols to be measured by each of the plurality of STAs. A sounding response frame is received from each of the plurality of STAs. The sounding response frame received from a first STA of the plurality of STAs is received at a short interframe spacing interval delay after completion of the sounding request frame transmission.

User end communication apparatus for managing broadcast channel input within a user end environment, comprises: a channel probe for obtaining channel context data from a stream at least passing through said user end communication apparatus; a keyword / key concept extractor for extracting channel keywords from the channel context data; and a content selector for selecting a content item or stream for mixing into a channel currently being viewed based on the channel keyword / key concept.

Method and apparatus for determining a downlink channel response in an orthogonal frequency division multiplexing access (OFDMA) system. The method and apparatus uses the uplink quality indication channel for determining the downlink channel response, or uses round trip pilot relay channel sounding. The uplink quality indication channel may comprise modified mini-tiles. The subscriber station using round trip pilot relay channel sounding sends composite transponder pilots after receiving the DL pilots.

Systems, devices and methods for updating link adaptations in multi-carrier modulated signals between an access point (AP) and a wireless local area network (WLAN) station (STA) include (are configured for) periodically transmitting a channel sounding signal from the AP. The STA receives each unsolicited channel sounding signal and evaluates the current channel conditions between the AP and STA. The AP adjusts a rate of transmission of the channel sounding signals in accordance with the channel coherence time so that the channel estimates performed by the STA will be valid within the time varying characteristics of the channel. Depending on the length of the coherence time for network environment, the channel sounding signals may be AP beacons, low overhead signal fragments with no payload, or a combination of both.

The invention discloses a communication method and wireless communication system for realizing multi-user dispatching. The method comprises the following steps: refining and multiplexing are carried out on physical resources in the wireless communication system so that multiple users can simultaneously access the physical resources in parallel; downlink transmission is carried out based on orthogonal frequency division multiple access (OFDMA) and multi-user-multiple-input and multiple-output (MU-MIMO) mechanism, and uplink transmission is carried out based on OFDMA or OFDMA+time division multiple access (OFMA+TDMA); an access point sends a multi-user polling frame or channel detection frame which carries an uplink transmission resource indication; a user station transmits data and feeds back channel status information according to the resource indication; and the system selects a user group for downlink data transmission and sends data to the users in the user group. According to the invention, a media access control (MAC) layer dispatching mechanism allowing multiple users to access simultaneously is achieved, and uplink and downlink services are comprehensively considered to realize two-way communication in the wireless communication system, thus the access delay can be obviously reduced, the system throughput can be obviously improved, and the requirement of accessing more multi-media services can be met.

A method of modulating communications signals, such as optical fiber, wired electronic, or wireless signals in a manner that facilitates automatic correction for the signal distortion effects of echoes and frequency shifts, while still allowing high rates of data transmission. Data symbols intended for transmission are distributed into N×N matrices, and used to weigh or modulate a family of cyclically time shifted and cyclically frequency shifted waveforms. Although these waveforms may then be distorted during transmission, their basic cyclic time and frequency repeating structure facilitates use of improved receivers with deconvolution devices that can utilize the repeating patterns to correct for these distortions. The various waveforms may be sent in N time blocks at various time spacing and frequency spacing combinations in a manner that can allow interleaving of blocks from different transmitters. Applications to channel sounding / characterization, system optimization, and also radar are also discussed.

A method for a channel sounding in a wireless local area network is provided. The method includes transmitting a null data packet announcement (NDPA) frame, to a plurality of receivers, the NDPA frame requesting a channel statement information feedback and announcing that a null data packet (NDP) frame is to be transmitted; transmitting the NDP frame being a basis of channel estimation for the plurality of receivers; receiving a first feedback frame from a first receiver among the plurality of receivers, transmitting a feedback poll frame to a second receiver; and, receiving a second feedback frame from the second receiver, the second feedback frame including second channel state information estimated by the second receiver. If the first receiver fails to perform the channel estimation, the first feedback frame is a null feedback frame. The null feedback frame is a feedback frame not including channel state information.

A method for generating a preamble of a frame for a multiple input multiple output (MIMO) wireless communication begins by, for each transmit antenna of the MIMO wireless communication, generating a carrier detect field, wherein, from transmit antenna to transmit antenna, the carrier detect field is cyclically shifted. The method continues by, for a first grouping of the transmit antennas of the MIMO wireless communication: generating a first guard interval following the carrier detect field; and generating at least one channel sounding field, wherein, from transmit antenna to transmit antenna in the first grouping, the at least one channel sounding field is cyclically shifted, and wherein the at least one channel sounding field follows the first guard interval. The method continues by, when the MIMO wireless communication includes more than the first grouping of the transmit antennas, for another grouping of the transmit antennas: generating at least one other channel sounding field, wherein, from transmit antenna to transmit antenna in the another grouping, the at least one other channel sounding field is cyclically shifted, and wherein the at least one other channel sounding field follows the at least one channel sounding field; and generating the first guard interval prior to the at least one other channel sounding field.

An Orthogonal Frequency Division Multiplexing communication system is provided that triggers a transmission of an uplink sounding signal by use of a Downlink Control Information (DCI) message. In various embodiments of the invention, the DCI message may be used to individually trigger an uplink sounding signal by a single user equipment or may be used to trigger an uplink sounding signal by a group of users equipment.

Methods and apparatus are provided to enable aperiodic sounding reference signaling including frequency hopping through the use of additional RRC configuration. The methods can require little or no additional L1 overhead to support narrowband frequency hopping for aperiodic sounding transmissions. In some embodiments, an approach is provided for extending an LTE periodic sounding reference signal methodology to include aperiodic sounding. One benefit of the proposed technique is that it enables each UE to perform aperiodic channel sounding in sounding subframes, using a frequency-hopping pattern, in which the sounding bandwidth of the UE can be narrowed appropriately to match its link capability. Additional benefits of the new approach include better resource utilization, lower signaling overhead, faster channel information update rates, and lower blocking probabilities.

A WLAN distributed / opportunistic scheduling (WDOS) method for acquiring a multi-user diversity gain is disclosed. The WDOS method allows a transmitter (i.e., a transmission user) to observe channel conditions of receivers (i.e., reception users), and commands the transmitter to transmit packets to a specific receiver having a relative good channel condition. The WDOS method uses a modified RTS / CTS exchange method to perform the channel probing. If the transmitter broadcasts the BRTS frame, each receiver transmits a CTS frame after the lapse of its backoff period. According to the reception signal strength distribution, the backoff delay time minimizes the number of CTS collisions irrespective of the number of receivers, reduces an amount of channel probing overheads, and maximizes a multi-user diversity gain. The better the relative channel condition, the lower the backoff delay time.

The invention discloses a D2D (Dimension To Dimension) pair / D2D cluster communication building method which comprises the following steps that: 1) initiator user equipment actively sends a cluster building request signaling code to a base station via a honeycomb link, wherein the content of the cluster building request signaling code comprises a communication mode, user equipment capability and a business label; 2) after the base station receives the cluster building request signaling code, the relevant information of the initiator user equipment is measured and analyzed so as to be combined with a system information selecting and scheduling mechanism to broadcast the cluster building request signaling code; 3) after the initiator user equipment and the adjacent user equipment receive the cluster building request signaling code, analysis is carried out by aiming at a cluster building strategy message; 4) the initiator user equipment sends a channel probing signal; the adjacent user equipment measures the D2D link quality; and the adjacent user equipment, which satisfies the requirement and serves as the candidate cluster use equipment, sends the cluster building confirmation message. According to the D2D pair / D2D cluster communication building method, the traditional cluster communication building flow simplified, resources are saved, and time delay is lowered.

A method and an apparatus to reproduce a 7.1 channel encoded sound through a 5.1 channel speaker system are provided. The apparatus includes a decoder to separate a 7.1 channel audio bitstream into 8 channel audio signals, a signal corrector to correct characteristics of a left channel audio signal, a right channel audio signal, a center channel audio signal, left and right surround channel audio signals, and a low frequency effect channel audio signal out of the 8 channel audio signals, a back surround filter to form virtual speakers for a left back channel audio signal and a right back channel audio signal at arbitrary locations using head related transfer functions measured at predetermined locations around a listener and to cancel crosstalk between the virtual speakers, and an adder to add the right surround channel audio signal output by the signal corrector to the right back channel audio signal output by the back surround filter and to add the left surround channel audio signal output by the signal corrector to the left back channel audio signal output by the back surround filter.

A speaker capable of suppressing deterioration of acoustic efficiency while allowing miniaturization of the speaker includes a first unit (20) and a second unit (21) each of which outputs sound. The first unit (20) includes: a diaphragm (25) which vibrates back and forth to radiate sound; and plural suspensions (26a, 26b, 26c, 26d) which support, at different positions, an outer periphery of the diaphragm (25). At least one of air passages (35a, 35b) for channeling sound from the second unit (21) to the outside is provided between the plural suspensions (26a, 26b, 26c, 26d).

Specifically, a method and system that performs MIMO and beamforming at a base station based on an uplink channel sounding (ULCS) from only one of the mobile station antennas and closed-loop multiple input, multiple output (MIMO) schemes based on the singular value decomposition (SVD) of the channel matrix. The ULCS is limited to sounding and the channel uses fewer than an optimal number of transmit antennas (e.g. one for WiMAX). The base station arrays may be configured for a full array transmitting mode or a sub-array transmitting mode.

The invention discloses a method for processing interference. The method comprises the following steps that: a user equipment (UE) receives uplink control channel configuration information of a cell in a neighboring base station, which is transmitted by a service base station, wherein the uplink control channel configuration information comprises physical uplink control channel (PUCCH) configuration information, physical random access channel (PRACH) configuration information or channel detection reference symbol Sounding (RS) configuration information of the cell in the neighboring base station; and the UE determines the position of the service base station, which is interfered by the neighboring base station, according to the configuration information, and eliminates the interference according to the determined position of the interference. The invention discloses a device for eliminating the interference.

A channel sounding method in a wireless local area network (WLAN) system is provided. The method, performed by a transmitter, includes transmitting a null data packet announcement (NDPA) frame to a receiver to initiate a channel sounding procedure; transmitting a null data packet (NDP) to the receiver and receiving a feedback frame. The feedback frame includes a plurality of segment frames and a channel feedback report. The channel feedback report is split into a plurality of feedback segments. Each of the plurality of feedback segments is respectively included in each of the plurality of segment frames. The each of the plurality of segment frames includes a first-segment subfield indicating whether the each of the plurality of feedback segment included is a first segment and a remaining-segment subfield indicating the number of remaining feedback segments.

A method and apparatus to generate a stereo sound for two-channel headphones from a multi-channel audio signal reproduced from a recording medium. The method may include generating a direct sound and reflected sounds by delaying one of a plurality of channel signals using a plurality of different delay coefficients, multiplying the generated sounds by predetermined different gain values, dividing the multiplied sounds into left and right channel sounds by reflecting a time difference between two ears of a listener on each of the multiplied sounds, low-pass-filtering the left and right channel sounds by reflecting a level difference between the two ears of the listener on each of the left and right channel sounds, and adding together the low-pass-filtered left channel sounds and the low-pass-filtered right channel sounds, respectively.

A technique of operating a wireless communication system includes determining respective geometries of multiple subscriber stations, which include a first subscriber station and a second subscriber station, with respect to a serving base station. Respective channel sounding bandwidths for sounding the channel between the multiple subscriber stations and the serving base station are then scheduled, based on the respective geometries. The respective channel sounding bandwidths include a first channel sounding bandwidth (associated with the first subscriber station) and a second channel sounding bandwidth (associated with the second subscriber station). The first channel sounding bandwidth is greater than or equal to the second channel sounding bandwidth and the first subscriber station has a lower geometry than the second subscriber station.

A technique for improving open loop power control in spread spectrum telecommunications systems is disclosed. In a preferred embodiment, the technique is realized by transmitting at least one first access channel probe for a first message from a mobile station to a base station, wherein the transmission power level of each access channel probe in the at least one first access channel probe is increased until a base station acknowledgment is received for a specific access channel probe of the at least one first access channel probe at a first transmission power level. The first transmission power level is then stored at the mobile station. At least one second access channel probe for a second message is then transmitted from the mobile station to the base station, wherein the transmission power level of an initial access channel probe of the at least one second access channel probe for the second message is based upon the first transmission power level.

An eyewear sound induction ear speaker device includes an eyewear frame, at least one speaker including an audio channel integrated with the eyewear frame and an acoustic duct coupled to the speaker and arranged to channel sound emitted by the speaker to an ear of the user wearing the eyewear frame. A method of providing sound for eyewear includes receiving an audio signal at a speaker integrated with an eyewear frame, inducing the speaker to produce an acoustic sound, and channeling the sound through an acoustic duct to be presented to a user wearing the eyewear frame. The eyewear can include microphones and at least one of a receiver and a transmitter that are integral to the eyewear frame and electronically linked to the at least one speaker. The microphones can be employed in noise cancellation.

A multi-channel surround sound expansion method is proposed. First, a two-channel stereo sound is read and then expanded into a Front L channel, a Front R channel, a Front M channel, a Rear L channel and a Rear R channel sound signals by means of the Hafler technique. Next, the sound reverberation technique is used to let the Rear L channel and Rear R channel sound signals generate sound with echo / reverberation. Finally, the Rear L channel and Rear R channel sound signals are delayed by a first time value, and the Front M channel sound signal is advanced by a second time value to emphasize the front sound field and the human voices, thereby producing a 3D sound field surrounding a listener.

System and method embodiments are provided for transmission and reception scheduling for wireless devices in a multi-user full duplex transmission environment. The embodiments enable interference avoidance between neighboring wireless devices. The system and method also enable channel sounding. In an embodiment, a method for scheduling transmissions in a multi-user wireless system includes determining, by a transmission point, neighboring wireless devices for each of a plurality of wireless devices located within a coverage area of the transmission point and determining, by the transmission point, a transmission schedules for respective ones of the plurality of wireless devices according to the neighboring information of the devices such that each respective wireless device is scheduled to transmit data over different time-frequency resources than those in which neighboring wireless devices of the respective wireless device are scheduled to receive data.

A method and system for achieving frequency domain scheduling in a time division duplex system is disclosed, the method comprising: a first device transmits a non pre-coded reference symbol to a second device; from the reference symbol, the second device obtains a channel impulse response matrix experienced by the reference symbol transmitted from the first device, and according to the channel impulse response matrix, obtains linear spatial domain pre-coding matrix of candidate physical resource blocks used in transmitting data to the first device; from the channel impulse response matrix and the linear spatial domain pre-coding matrix, the second device obtains the channel quality indication of the candidate physical resource blocks; and performs the frequency domain scheduling according to the channel quality indication. The use of the method not only solves the problem in the prior art that the frequency domain scheduling is unable to be performed when a channel sounding method is employed, but also the contradiction in the use of the frequency domain scheduling and the linear spatial domain pre-coding. A communication system is also disclosed.

A method for reference signal transmission is disclosed, wherein a demodulation reference signal DMRS and a sounding reference signal SRS is transmitted in a same time domain resource from a user terminal to an LTE base station. A single reference signal sequence is used both for demodulation and detection of a data channel, and for channel sounding, such that a reference signal sequence part used for the demodulation and detection of the data channel is in a power offset compared to a reference signal sequence part used for the channel sounding. Code division multiplexing is applied on a reference signal sequence by using a cyclic shift of a whole length of the sequence. The cyclic shift is selected such that reference signal sequences allocated to the different user terminals are orthogonal over a minimum allocation granularity of the data channel.

An apparatus for adapting hyper cells in response to changing conditions of a cellular network is disclosed. During operation, the apparatus collects data regarding network conditions of the cellular network. In accordance with the collected network condition data, the apparatus changes an association of a transmit point from a second cell ID of a second hyper cell to a first cell ID of a first hyper cell. Virtual data channels, broadcast common control channel and virtual dedicated control channel, transmit point optimization, UE-centric channel sounding and measurement, and single frequency network synchronization are also disclosed.

Systems and techniques are disclosed to enhance the efficiency of available bandwidth between UEs and base stations. A UE transmits a sounding reference signal (SRS) to the base station. The base station characterizes the uplink channel based on the SRS received and, using reciprocity, applies the channel characterization for the downlink channel. As part of applying the channel information, the base station forms the beam to the UE based on the uplink channel information obtained from the SRS. The UE may include an array of antennas, each UE transmitting a different SRS that the base station receives and uses to characterize the downlink. Multiple UEs (or a single UE with multiple antennas) transmit SRS at the same time and frequency allocation (non-orthogonal), but with each sending its own unique SRS. Further, multiple UEs (or a single UE with multiple antennas) may send their SRS at unique time / frequency allocations (orthogonal).

Systems, devices and methods for updating link adaptations in multi-carrier modulated signals between an access point (AP) and a wireless local area network (WLAN) station (STA) include (are configured for) periodically transmitting a channel sounding signal from the AP. The STA receives each unsolicited channel sounding signal and evaluates the current channel conditions between the AP and STA. The AP adjusts a rate of transmission of the channel sounding signals in accordance with the channel coherence time so that the channel estimates performed by the STA will be valid within the time varying characteristics of the channel. Depending on the length of the coherence time for network environment, the channel sounding signals may be AP beacons, low overhead signal fragments with no payload, or a combination of both.