417results about How to "Increase channel capacity" patented technology

Acoustic telemetry devices and methods that provide directional detection. In one embodiment, a disclosed acoustic telemetry device comprises at least two acoustic sensors and an electronics module. A first of the acoustic sensors detects a communication signal that propagates along a tubing string in a first direction. A second of the acoustic sensors is configured to detect the communication signal before the first acoustic sensor. The electronics module combines the detection signals from the acoustic sensors to obtain a combined signal that substantially excludes signals propagating in a direction opposite to the communication signal. Such signal suppression may significantly enhance the communication signal's signal-to-noise ratio, thereby increasing channel capacity. The acoustic telemetry device may be configured to support logging while drilling and/or full-duplex communication.

A multi-stage data logging system comprising a telecommunications stage for receiving, processing, and compressing data from one or more input channels, a recorder stage for storing said data to a memory device, a distribution stage for retrieving said stored data and distributing said data to one or more output channels, and a plurality of interface paths linking said three stages to one another. Different stages of the system can be located wide distances apart and the interface paths linking the three stages can be automatically switched to achieve fault tolerance of the system.

This invention relates to a transmission power control method and transmission power control apparatus in a mobile communication system. The reception quality of a signal (31, 32a, 32b, 41, or 42) transmitted from another mobile station (51 or 52) or base station (21 or 22) is compared with a predetermined control target value such as a signal-to-interference ratio. The comparison result is used for transmission power control on a remote station. If a frame error is detected in a transmitted signal, the control target value is increased by SIRinc. If no frame error is detected, the control target value is decreased by SIRdec. As SIRdec, the product of a target value of a frame error rate and SIRinc is set. With this operation, when a propagation environment such as multibus or moving speed changes, the control target value for transmission power control is changed within a short period of time, and channel quality is maintained constant, thus realizing desired channel quality.

In a wireless communication system for communicating with a plurality of stations at the same point of time with the same frequency using a Space Division Multiple Access (SDMA), wireless resources are allocated by a first decision unit which evaluates performance of each station obtained when the SDMA is used and which determines periods of time to be allocated to groups of stations formed according to the SDMA technique. Using a first evaluation unit and a second evaluation unit to evaluate performance required by each station and each application, the first decision unit allocates the wireless resources to the stations. It is therefore possible that the wireless resources are efficiently allocated to the stations while preventing an event in which the wireless resources are excessive or insufficient for required quality of service.

The present invention advantageously provides a method and apparatus for optimization of channel capacity in multi-line multi-tone communications such as X-DSL among subscriber lines which are bundled with one another. In an embodiment of the invention an apparatus for optimizing channel capacity of multi-tone communications effected by opposing sets of modems coupled to one another by a plurality of subscriber lines is disclosed. The apparatus includes a spectrum manager coupled to at least one of the opposing sets of modems. The spectrum manager includes: a profiler, a demand module and an optimizer. The profiler obtains from the at least one of the opposing sets of modems the spectral characteristics of each of the plurality of subscriber lines. The demand module determines for each of the plurality of subscriber lines the subscriber demand profile. The optimizer defines target parameters for at least one of bit loading, and power spectral density (PSD) for selected tones of the multi-tone communications based on the spectral characteristics from the profile module and the demand profiles from the demand module and downloads the target parameters to the at least one of the opposing sets of modems.

A multiple-access digital radio communication system and method with communication links between user terminal transmitters and central node with a receiver system including a multibeam antenna. User terminal transmitters assigned to one beam coverage region use mltiple access channels that are mutually orthogonal for transmitting digital message information. These multiple access channels are reused in adjacent and other beam coverage regions. Error-correction coding (20), interleaving (21), and a single-axis modulator (24) are used in the user transmitter to increase resistance to potential interference from user terminal transmitters in other coverage regions. At the receiver, an adaptive processor (28) such as an equalizer or sequence estimator is used to combine multiple antenna beam signals (27) to produce a combined signal associated with each user. Deinterleaving (30) and error-correction decoding (31) of the combined signal is used to complete the recovery of the digital message information.

A multiple-access digital radio communication system and method with communication links between user terminal transmitters and a central node with a receiver system including a multibeam antenna. User terminal transmitters assigned to one beam coverage region use multiple access channels that are mutually orthogonal for transmitting digital message information that is included in a data group. Assignments are random and are changed for successive data groups. The same multiple access channels are reused in adjacent and other beam coverage regions each with an independent random assignment algorithm. Error-correction coding and interleaving are used in the user transmitter and an adaptive processor is used in the receiver. A reference sequence unique to either each user or each beam coverage region is multiplexed into user data groups for transmission. At the receiver the adaptive processor such as an equalizer or sequence estimator is used to combine multiple antenna beam signals to produce a combined signal associated with each user. The combining in the adaptive processor reduces interference from user terminal transmitters associated with different beam coverage regions but with the same multiple access channel. Deinterleaving and error-correction decoding of the combined signal are used to protect against channel assignments with larege mutual interference levels. The communication system can reuse each orthogonal multiple access channel in all of the other beams, i.e., a reuse factor of unity for each multiple access channel.

An antenna weight estimation method in a mobile communication system is capable of improving the accuracy of antenna weight estimation values, thereby improving communication quality and increasing radio channel capacity. It operates instantaneous estimation and accumulative estimation in parallel, in which the former is made for estimating the antenna weight used for received SNIR estimation for transmission power control, and the latter is made for demodulating the received data. Thus, it can obtain the antenna weight for the received SNIR measurement with a minimum delay, and at the same time, it can improve the reliability of the antenna weight for the data demodulation.

Provided is a method of controlling a multiple input multiple output (MIMO) system. One embodiment of the method includes the steps of: estimating, at a receiver, a MIMO channel and detecting data streams using a successive interference cancellation scheme; calculating, at the receiver, S and P using the estimated channel and then feeding back information corresponding to (P₁, P₂, . . . , P_M-1, SINR⁵_M) to a transmitter, and determining, at the transmitter, a transfer rate and transmission power perstream using the fed-back information. Another embodiment of the method includes the steps of: estimating, at a receiver, a MIMO channel and detecting data streams using a signal received from an antenna; extracting, at the receiver, a feedback parameter to be fed back to the transmitter using the estimated channel, and feeding back the feedback parameter to the transmitter, and determining, at the transmitter, a stream to be allocated to the receiver from among the streams of the transmitter using the fed-back parameter and a data transfer rate per stream, wherein the feedback parameter is information corresponding to a successive interference cancellation order and a signal-to-interference-plus-noise ratio (SINR) per stream reflecting successive interference cancellation.

The invention provides a method for selecting a full-duplex antenna in a multiple-in multiple-out (MIMO) system. The method comprises the following steps of: 1, performing self-interference elimination on receiving antennae at two communication ports in a full-duplex antenna system to acquire corresponding self-interference channels; 2, performing equalization processing on signals received by the receiving antennae at the two communication ports to acquire postprocessing signals of corresponding transmitting antennae; 3, when distribution of the self-interference channels corresponding to the receiving antennae at the two communication ports accords with independent identically distributed Rice distribution, calculating the postprocessing signal to interference and noise ratio of the receiving antennae at the two communication ports; and 4, traversing all antenna pairs between the two communication ports based on antenna selection criteria to determine a final antenna matching scheme. The advantages of a full-duplex antenna technology and an MIMO technology are combined, a scheme with gain is selected from all possible antenna matching schemes, channel capacity is improved, and the whole performance of the system is improved.

Disclosed is a method for transmitting a channel signal in a base station of a mobile communication system which scrambles a common channel signal using a primary scrambling code for identifying the base station. The method comprises determining an identifier (ID) of a secondary scrambling code, upon receipt of a dedicated channel assignment request from a mobile station; transmitting the determined ID of the secondary scrambling code to the mobile station and awaiting a response; upon receipt of a response message from the mobile station, generating a primary scrambling code and a secondary scrambling code using an ID of the primary scrambling code and said ID of the secondary scrambling code; and scrambling a common channel signal using the primary scrambling code, scrambling a dedicated channel signal using the secondary scrambling code, and transmitting the scrambled channel signals.

The invention relates to a multi-input and multi-output selectivity OFDM underwater sound communication system and a method thereof, having the advantages of resisting multi-path interference, resisting frequency selectivity deep fading, improving the transmission rate of information and the like. The transmitter of the system comprises a space multiplexing unit, a plurality of spectrum spreading units, a subcarrier zero setting unit, a plurality of OFDM modulation units, a multiple sonar transmitting unit and a communication channel estimation unit, wherein, the spectrum spreading units are connected between the space multiplexing unit and the subcarrier zero setting unit; the OFDM modulation units are connected between the subcarrier zero setting unit and the multiple sonar transmitting unit. A receiver comprises a multiple sonar receiving unit, a plurality of OFDM demodulation units, a communication channel frequency domain balancing unit, a plurality of dispreading units and space demultiplexing units, the OFDM demodulation units are connected between the multiple sonar receiving unit and the communication channel frequency domain balancing unit, the dispreading units are connected between the communication channel frequency domain balancing unit and the space demultiplexing unit, and the communication channel estimation unit is respectively connected with the subcarrier zero setting unit and the communication channel frequency domain balancing unit.

The invention discloses a four-color LED light mixing method based on visible light communication. The method comprises the steps that spectral power distribution of all monochromatic light is obtained through a spectrograph, and the tristimulus value of each corresponding monochromatic light is calculated; the target color temperature of mixed light is determined, and a corresponding reference light source is selected and used for obtaining the tristimulus value of a mixed color; according to the color addition principle, the sum of the tristimulus values of all the monochromatic light should be equal to the tristimulus value of the mixed color, and a color mixing equation set is obtained; the spectral power distribution of the mixed light can be obtained according to the light mixing coefficient of all the monochromatic light in the color mixing equation set, and the color rendering index Ra of the mixed light is calculated according to the spectral power distribution of the mixed light, wherein Ra is larger than or equal to epsilon; the range of the channel capacity C of the mixed light is calculated, and the maximum capacity Cmax is solved within the range; the ratio of all the colored light with the maximum capacity is output.

To improve the channel capacity of an entire communication system in accordance with transmission quality of the channels of each node. A relay node has: a receiving section that receives a received signal from a source node; a channel estimation section that measures SNR of a backward channel between the source node and the relay node, and SNR of a forward channel between the relay node and a destination node; a relay selecting section that selects, from among a QR-P-ZF method, a QR-P-QR method and a ZF-P-QR method, a relay method of the relay node in accordance with the ratio between the SNRs of the backward and forward channels; a relay signal processing section that multiplies the received signal by a transmission weight matrix corresponding to the selected relay method, and thereby converts the received signal to a relay signal; and a transmitting section that transmits the relay signal to the destination node.

The invention discloses an underwater sound communication system, wherein a transmitter comprises an MIMO space multiplexing unit, a plurality of spectrum spreading units, a plurality of SC-FDE pretreatment modules and a plurality of transmitting sonars; a plurality of output ends of the MIMO space multiplexing unit are in one-to-one connection with the plurality of the spectrum spreading units; each spectrum spreading unit is connected to one SC-FDE pretreatment module; each SC-FDE pretreatment module is connected to one transmitting sonar; a receiver comprises a plurality of receiving sonars, a plurality of filtering detecting units, a plurality of SC-FDE modules, a plurality of dispreading units, and an MIMO demultiplexing unit; each receiving sonar is connected with one filtering detecting unit; each filtering detecting unit is connected to one SC-FDE module; each SC-FDE module is connected to one dispreading unit; and the plurality of the dispreading units are in one-to-one connection with a plurality of input ends of the MIMO demultiplexing unit. The system can resist multipath interface, improve frequency spectrum utilization ratio, channel capacity, information transmission rate and confidentiality, compensate Doppler frequency shift and reduce signal-to-noise ratio.

A combined signal processing method for a source end and a relay end in a bidirectional relay system comprises the following steps: the source end emits a training sequence to a relay, and the relay performs backward channel estimation to obtain an estimation channel between the source end and the relay; the relay emits a training sequence to the source end, and the source end performs forward channel estimation to obtain an estimation channel between the relay and a user; the source end feed forward channel information back to the relay, the relay performs iterative computation to source end nonlinear pre-coding matrixes, relay linear pre-coding matrixes and source end receiving equalization matrixes; the relay feeds the information of the source end back to the source end; emitting signals are subjected to nonlinear pre-treatment through the source end and then emitted to the relay; the signals received by the relay are subjected to linear pre-treatment through the relay and then broadcasted to the source end; and the source end detects the received signals to obtain information required to be transmitted therebetween. According to the invention, the bidirectional relay information transmission mode is adopted to improve the channel capacity, and the nonlinear signal processing method is adopted at the source end, so that the bit error rate performance of the system is improved.

The invention relates to a tripolar magneto-dipole MIMO (multiple input multiple output) antenna system and belongs to the technical field of wireless communication systems. A tripolar magneto-dipole MIMO antenna is composed of a first loop antenna, a second loop antenna and a third loop antenna which are mutually orthogonal. Geometric centers of the first, the second and the third loop antennas are located at one spatial point and feed respectively. Each loop antenna has evenly distributed current; meanwhile, the first, the second and the third loop antennas are low in coupling; MIMO channel capacity is high accordingly. The compact MIMO antenna with high channel capacity is composed of the coincident low-coupled tripolar magneto-dipoles. Extraction and utilization of three magnetic field polarization components are achieved, and three polarization degrees of freedom of the magnetic field components can be acquired accordingly.