1440 results about "Transmission errors" patented technology

An HARQ method for guaranteeing a QoS in a wireless communication system is provided. In a transmitting apparatus using a HARQ for transmitting packet data in a wireless communication system, a retransmission controller determines the size of redundancy information for correcting transmission errors in packet data, and a transmitter transmits the redundancy information of the determined size upon request for a retransmission of the packet data. Transmission of redundancy information of a variable size at each retransmission satisfies the QoS required for each user, maximizes a data throughput, and allows for the efficient reception of an ACK or a NACK for the redundancy information.

This invention describes a video surveillance system which is composed of three key components 1—smart camera(s), 2—server(s), 3—client(s), connected through IP-networks in wired or wireless configurations. The system has been designed so as to protect the privacy of people and goods under surveillance. Smart cameras are based on JPEG 2000 compression where an analysis module allows for efficient use of security tools for the purpose of scrambling, and event detection. The analysis is also used in order to provide a better quality in regions of the interest in the scene. Compressed video streams leaving the camera(s) are scrambled and signed for the purpose of privacy and data integrity verification using JPSEC compliant methods. The same bit stream is also protected based on JPWL compliant methods for robustness to transmission errors. The operations of the smart camera are optimized in order to provide the best compromise in terms of perceived visual quality of the decoded video, versus the amount of power consumption. The smart camera(s) can be wireless in both power and communication connections. The server(s) receive(s), store(s), manage(s) and dispatch(es) the video sequences on wired and wireless channels to a variety of clients and users with different device capabilities, channel characteristics and preferences. Use of seamless scalable coding of video sequences prevents any need for transcoding operations at any point in the system.

An Explicit Congestion Notification (ECN) method is disclosed for wireless applications to avoid network congestion in a TCP / IP packet-switched network. Such method comprises transmitting, at a source node, data packets to a destination node, via at least an intermediate node; determining, at the intermediate node, if an incipient congestion is encountered, setting a Congestion Experienced (CE) flag in each data packet to notify congestion; sending, at the destination node, an ECN-Echo acknowledgment packet back to the source node to inform congestion; reducing, at the source node, a congestion window and a transmission rate to avoid congestion; if the packet loss is due to congestion, re-transmitting, at the source node, only a lost packet to the destination node; alternatively, if the packet loss is due to transmission error, re-transmitting, the lost packet to the destination node, while increasing a round-trip timeout but maintaining the same congestion window.

An information processing apparatus and method for reducing an unnecessary waiting time in a depacketizing process and enabling processing to be easily performed at high speeds applicable to, for example, an encoding apparatus. An analysis unit compares input image data with image data of one previous picture read out from a storage unit. On the basis of the analysis result, a concealment header generation unit generates a concealment header that is referred to by a receiving apparatus at the time of an error concealment process. On the basis of the concealment header, a loss analysis unit performs error concealment for the occurrence of a transmission error by suitably using encoded data stored in a storage unit.

A mobile terminal is adapted to operate in a WLAN and a WWAN. The mobile terminal performs communication operations using its WLAN transceiver portion for maintaining a voice or data call via a wireless AP of the WLAN. During this time, the mobile terminal identifies a RSSI value and a SNR value of an RF signal of the wireless AP. When the RSSI value is less than a predetermined RSSI value, and the SNR value is less than a predetermined SNR value, the mobile terminal provides an indication to switch the communication operations from the WLAN to the WWAN. However, when the RSSI value is less than the predetermined RSSI value, but the SNR value is greater than the predetermined SNR value, the mobile terminal provides an indication to maintain the communication operations in the WLAN. In a concurrent process, the mobile terminal determines a transmission error value for data packet transmissions based on a count of data packet errors identified over a predetermined time period. A transmission error percentage value is calculated based on the transmission error value and the total number of attempted data packet transmissions over the predetermined time period. When the transmission error percentage value is greater than a predetermined percent error value, the mobile terminal provides the indication to switch the communication operations from the WLAN to the WWAN.

A method and system for controlling drive of a robot having two or more drive axes and driven in accordance with an action program transmitted from a system controller to a robot controller by a wireless transmission way, checks whether a detected current position of the robot coincides with a predetermined start position of the robot in terms of the drive axes, and allows the robot to be driven in accordance with the designated action program when the detected current position coincides with the predetermined start position. Failure in the position control of the robot due to transmission error is prevented by the position checking.

An apparatus for adjusting the transmission bit rate and fragmentation threshold of a wireless station in response to transmission errors is disclosed. In particular, the illustrative embodiment of the present invention is based on a wireless station that employs both an IEEE 802.11 radio and a Bluetooth radio, and determines whether transmission errors of the IEEE 802.11 radio are due to fading, or interference from the Bluetooth radio. It will be clear to those skilled in the art how to make and use alternative embodiments of the present invention for protocols other than IEEE 802.11 and Bluetooth, as well as stations that employ wireline or non-RF-wireless transceivers.

A point-to-multipoint communications network includes an optical line terminal (OLT) and a number of optical network terminals (ONTS) which each detect and remove rogue ONTs from the network. The OLT monitors transmission errors to detect the presence of a rogue ONT, and can determine the identity of the rogue. Each ONT monitors its own upstream data packets to detect the presence of a rogue, and turns itself off when a rogue is detected.

A real-time program transmission system and method may receive a signal from a content source, and generate two different data streams. One stream may be of a higher quality than the other. The two streams may then be inserted into time slice frames, such that a single frame carries two portions of data: one corresponding to a first time segment in the program, and a second corresponding to a different time segment in the program. A receiving mobile terminal may buffer the received data, and may use the lower quality data as a backup in the event of a transmission error in the higher quality data.

A scalable, minimum node complexity, energy efficient, and error-resilient routing method for wireless sensor networks is described. The network is partitioned into regions by power controlled base station scans using a directional antenna. Routing is performed using only local location information and instructions received from the base station at each sensor node with minimum processing and control overhead, thus allowing simple, low-cost sensor designs. Sensors in the network provide to a base station reports of the condition of the sensors themselves, and these reports are analyzed by the base station to determine improved routing instructions, which are then provided to the sensor nodes in control messages. Each data packet is relayed in an interleaved, loop-free mesh of sectors toward the base station, making data delivery robust to sensor failures and transmission errors. The disclosure also contains descriptions for simple edge-based tasking, query, code distribution, and network programming for sensor nodes. The method is suitable for large-scale, dense sensor networks for detection, alarming, and monitoring applications.

In a method for concealing an error in an encoded audio signal a set of spectral coefficients is subdivided into at least two sub-bands (14), whereupon the sub-bands are subjected to a re-verse transform (16). A specific prediction is performed (18) for each quasi time signal of a sub-band to obtain an estimated temporal representation for a sub-band of a set of spectral coefficients following the current set. A forward transform (20) of the time signal of each sub-band provides estimated spectral coefficients which can be used (28) instead of erroneous spectral coefficients of a following set of spectral coefficients, e.g. in order to conceal transmission errors. Transforming at the sub-band level provides independence from transform characteristics such as block length, window type and MDCT algorithm while at the same time preserving spectral processing for error concealment. Thus the spectral characteristics of audio signals can also be taken into account during error concealment.

A real-time program transmission system and method may receive a signal from a content source, and generate two different data streams. One stream may be of a higher quality than the other. The two streams may then be inserted into time slice frames, such that a single frame carries two portions of data: one corresponding to a first time segment in the program, and a second corresponding to a different time segment in the program. A receiving mobile terminal may buffer the received data, and may use the lower quality data as a backup in the event of a transmission error in the higher quality data.

A system, method and data structure for error correction for use in the transmission of content data distribution networks uses a compressed memory, for example a bitmap, to identify portions of transmitted content data files where transmission errors have occurred. The error memory, is used to generate an error status report that is returned to a transmission controller via a low bandwidth back channel, for example the Internet. The information in multiple error status reports is aggregated by the control system of the transmitter and used to re-transmit those portions of previously transmitted content data files that were not properly received due to error. By re-transmitting only the data packets of the transmitted content data files that contain errors, overall transmission speed is increased and bandwidth usage is conserved.

The invention provides a broadcast reception apparatus allowing, when a reception status is worsened in a child device, to automatically view the broadcast program that has been viewed in the child device, in continuation in a parent device. A parent / child television system include an antenna 1, a parent device A100, a child device B200 capable of wireless communication with the parent device A100, and a remote control 33. When a broadcasting is viewed in the child device B200 utilizing a digital tuner B12 of the parent device A100, a CPU-B58 of the child device B200 watches the reception state of the child device B200, and in case a transmission error is found frequently and another digital tuner A2 of the parent device A100 is not in use, a CPU-A 38 of the parent device A100 terminates transmission of a transport stream data to the child device B200 and sets the digital tuner A2, a video decoder A6 and an audio decoder A7 in a state where broadcast program can be viewed in the parent device A100.

A system and method for efficiently detecting and correcting transmission errors in packet-based communications by using cumulative error detection codes. The system may comprise a transmitting unit, which transmits one or more data packets. Each of the transmitted packets may comprise a plurality of transmission subunits. The transmitting unit preferably generates a cumulative error detection code (e.g., cumulative CRC code) for each of the transmission subunits of a packet. The system may further comprise a receiving unit to receive each of the transmission subunits of the packet. The receiving unit preferably generates a new cumulative error detection code for each of the received transmission subunits. The new cumulative error detection code is compared to the received cumulative error detection code to determine if any errors occurred in the transmission of the transmission subunit.

There is disclosed a method of dynamic transmission resource allocation in a wireless network comprising a plurality of Mobile Terminals or MTs each managing a given number of different data flows (4-9) of Protocol Data Units or PDUs which are classified according to a set of flow types, a Radio Resource Management or RRM unit for allocating transmission resources on a per PDU basis; a plurality of schedulers (2,3) operating according to a specific set of rules; and a selector (1) for sharing the transmission resource among the MTs. The MTs or the RRM unit send Request Resource or RR messages to the RRM unit to request transmission resource. The RRM unit dispatches the RR messages to the schedulers based on flow type information included in each RR message. Each one of the schedulers elects one PDU as candidate for a next transmission resource allocation. The selector (1) allocates transmission resource to one candidate according to a set of priority rules, a given priority being assigned to each flow type. The specific set of rules comprises a rule applied in case of transmission errors for reducing the bandwidth allocated to data flows belonging to the flow types assigned with comparatively lower priority compared to the bandwidth allocated thereto according to a rule applied in case of error free transmission.

A method of concealing transmission error in a digital audio signal in which a signal that has been decoded after transmission is received, the samples decoded while the transmitted data is valid are stored, at least one short-term prediction operator and one long-term prediction operator are estimated as a function of stored valid samples, and any missing or erroneous samples in the decoder signal are generated using the operators estimated in this way, the method being characterized in that the energy of the synthesized signal as generated in this way is controlled by means of a gain that is computed and adapted sample by sample.

A wireless communications device for a multiple input multiple output wireless communications system includes a radio frequency transceiver that includes at least two antennae and a medium access control device that includes a link adaptation module. The link adaptation module dynamically adjusts a bandwidth of the wireless communications device based on a transmission error rate and a correlation measurement at a remote wireless communications device. A transmission error module receives the transmission error rate from the remote wireless communications device and generates a transmission error control signal. A signal correlation module receives the correlation measurement from the remote wireless communication device and generates a signal correlation control signal. The link adaptation module adjusts at least one of the bandwidth and an amount of spatial multiplexing that is executed by a space-time processor based on the transmission error control signal and the signal correlation control signal.

The invention discloses a segmented cyclic redundancy check method for polarization codes mainly in order to solve the problems of high decoding complexity and high block error rate in the prior art. According to the technical scheme, the method comprises the steps as follows: first, the correct probability of the estimated value of each bit channel is calculated, and a channel for transmitting non-fixed bits is selected according to the probability; then, according to the correct probability of the estimated value of the channel for transmitting non-fixed bits, an information bit sequence is divided into sub information bit sequences, and segmented CRC check is carried out; next, polarization coding is carried out on the bit sequence joining in the segmented CRC check; and finally, the coded sequence is transmitted in the channel. Compared with the prior art, the method has the advantage that the method reduces the decoding complexity, improves the block error rate of decoding, and can be used to reduce the transmission error probability in the process of wireless communication.

Disclosed herein is a system and method for reconstruction video information lost as a result of transmission errors. The system and method have four aspects, including: (1) changing the bit and / or packet rate; (2) inserting redundant information into the video bitstream; (3) providing automatic refresh of certain regions of the video on a periodic basis; and (4) interleaving coded macroblocks into diversity groups for transmission to spatially spread the effect of lost packets. The image reconstruction may then take advantage of these three aspects to provide an enhanced result in the presence of transmission losses.

Disclosed herewith is a communication method employed for a wireless communication system. The method controls retransmission in case where wireless communication between a data transmitter and a data receiver in the system is unstable, thereby suppressing increasing of a communication delay time that might otherwise be caused by the retransmission control, thereby reducing transmission error occurrence. The transmitter node transmits a wireless signal including data while the receiver node receives the wireless signal and checks the received signal for error existence. If not detecting any error in the received data, the receiver node transmits an ACK (Acknowledgement) signal to the transmitter node. If detecting an error in the received data, the receiver node does not transmit the ACK (Acknowledgement) signal to the transmitter node. At this time, an interception node intercepts the data transmitted from the transmitter node and stores the intercepted data in a data storage unit. And if not detecting the ACK (Acknowledgement) signal transmitted from the receiver node, the interception node retransmits the stored data to the receiver node. If detecting the ACK (Acknowledgement) signal, the interception node does not retransmit the stored data to the receiver node.

A system and a method for encoding and decoding ultra-wideband information are provided. An ultra-wideband transmission is encoded by positioning bipolar pulse pairs. The bipolar pulse pairs assist in detecting errors in the ultra-wideband transmission, before the entire transmission has been received. The transmission is analyzed for errors and an error rate is calculated. The calculated error rate is compared to one or more predefined acceptable error rate levels to determine whether the calculated error rate of the transmission is within at least one of the predefined acceptable error rate levels.

Adaptive FEC coding is used to adjust the codeword composition of FEC codewords in a communication system. A codeword composition ratio may be adjusted in response to variance of a measured transmission error value from a target transmission error value in the system. The codeword composition ratio may be any quantity or value that represents the relation between the payload and parity bytes in the applicable FEC coding scheme. Adjustment of the codeword composition ratio may be adjusting parameters such as the N, K and / or R values in ADSL1 systems or the INP and / or maximum interleaving delay values in ADSL2 systems. A controller may be used to monitor, analyze and adjust the various values used in adaptively managing FEC coding. The present invention may be implemented in a transmission system in which a transmitter transmits data to a receiver via a transmission channel, such as a DSL system.

In a data transmission system, a server is provided with a data storage unit which holds plural video streams having different I-frame intervals, as coded data corresponding to the same video sequence, and a data transmission unit for transmitting a predetermined video stream among the plural video streams, according to a command signal Sc from a receiving terminal. The receiving terminal transmits a data designation signal (command signal) Sc which designates one of the plural video streams stored at the server end, to the server, on the basis of the contents of user setting. Therefore, at the receiving terminal, a video stream to be supplied from the transmitting end (server) can be selected between one having a high resistance to transmission error and one having a high video quality, according to the user's preference.

A data transmission system includes at least one transmission line. A sender is configured to send data frames to the at least one transmission line and a recipient is configured to receive the data frames from the at least one transmission line. The sender and the recipient are both configured to determine a check sum based on a plurality of corresponding data frames that are sent to and, respectively, received from the at least one transmission line. A check sum comparing unit is configured to receive and to compare the check sum determined by the sender and the corresponding check sum determined by the recipient. The check sum comparing unit is also configured to signal a transmission error or initiate a safety function when the check sums compared are not equal.

In a wireless network system having a wired backbone network, one or more access points (APs), and one or more wireless units (WUs), a technique wherein an AP automatically determines a factor indicative of the error(s) occurring in the transmissions of one or more data packets to associated WUs, and automatically adjust the fragmentation threshold in accordance with the transmission error factor. The AP adjusts the fragmentation threshold in a manner that the data throughput is increased. Since the AP automatically and periodically gauges the wireless medium for RF interference that can cause data transmission errors, the fragmentation threshold can be dynamically adjusted to respond to changes in the wireless medium, such as when a microwave oven is turned on, and / or when a Blue Tooth device is traversing the wireless medium, etc. This is much more effective than having a system administrator periodically gauge the wireless medium for the purpose of selecting the appropriate fragmentation threshold.

A bridge usable in a highly reliable industrial control system provides an interface between a producer module transmitting redundant messages in accordance with a communication protocol and a consumer module receiving the messages in accordance with a different communication protocol. The bridge includes a first network interface receiving two messages from the producer, a microprocessor capable of converting the messages from the producer communication protocol to consumer communication protocol, and a second network interface transmitting the messages to the consumer. One of the messages is reversible altered with respect to the other message. The altered message is uninverted in the consumer module, and compared to the other message to ensure that no transmission errors have occurred.