3395results about "Error prevention/detection by transmission repeat" patented technology

A wireless packet data communications system that includes a number of modem pool transceivers (MPTs), one or more modem pool controllers (MPCs), and one or more servers. Each MPT receives and processes data packets to generate a modulated signal (e.g., a CDMA spread spectrum signal) suitable for transmission over a terrestrial communications link. Each MPC provides call related processing for one or more MPTs. The servers couple to the MPTs and MPCs via an Internet Protocol (IP) back-bone and provide management of the communications system. The IP back-bone further interconnects the MPTs with one or more data networks and includes a number of routers that route data packets between the data networks and the MPTs. Each MPT can couple to two or more routers for redundancy. Each MPT is operated as an element in an IP network and is associated with an IP address that identifies the MPT. One to three MPTs can be deployed at each cell site to provide wireless data service coverage for up to three sectors at the cell site. The MPCs can either be centralized and coupled to the MPTs via the IP back-bone or distributed about the communications system.

Embodiments of the invention enable minimum latency site independent real-time video transport over packet switched networks. Some examples of real-time video transport are video conferencing and real-time or live video streaming. In one embodiment of the invention, a network node transmits live or real-tine audio and video signals, encapsulated as Internet Protocol (IP) data packets, to one or more nodes on the Internet or other IP network. One embodiment of the invention enables a user to move to different nodes or move nodes to different locations thereby providing site independence. Site independence is achieved by measuring and accounting for the jitter and delay between a transmitter and receiver based on the particular path between the transmitter and receiver independent of site location. The transmitter inserts timestamps and sequence numbers into packets and then transmits them. A receiver uses these timestamps to recover the transmitter's clock. The receiver stores the packets in a buffer that orders them by sequence number. The packets stay in the buffer for a fixed latency to compensate for possible network jitter and/or packet reordering. The combination of timestamp packet-processing, remote clock recovery and synchronization, fixed-latency receiver buffering, and error correction mechanisms help to preserve the quality of the received video, despite the significant network impairments generally encountered throughout the Internet and wireless networks.

The present invention relates to a wireless communication system, and more particularly, discloses a method and an apparatus for transmitting and receiving duplicate data in a multicarrier wireless communication system. According to one embodiment of the present invention, a method in which a transmitter, which supports carrier aggregation for performing communication using N (N≧2) component carriers, transmits duplicate data, comprises the steps of: generating, in a media access control (MAC) layer of the transmitter, N duplicate data using radio link control (RLC) protocol data units (PDUs) from an RLC layer, and simultaneously transmitting, to a receiver, the respective N duplicate data on the N component carriers through respective N hybrid automatic repeat and request (HARQ) entities.

This invention extends the range of optical data of mobile device by trading speed for distance as well as integrating a plurality of pulses over time to define a single bit of information. The present invention uses a number of integrated pulses to represent a single bit instead of utilizing a one to one correspondence between pulses and bits. The present invention executes a range extender application which executes on the mobile device without any hardware modification to the mobile device. The range extender application causes the optical transmitter to “stutter” or repetitively emanate the identical pulse representing a bit of information. Sufficient photons are thereby gathered at a receiver to reach a predetermined threshold. A tradeoff of the data transmission frequency in this invention is that a signal intensity drops by a factor of 100 when distance increases by a factor of 10 yielding a distance/intensity ratio of {fraction (1/10)}.

A method and apparatus for improving the speed and quality of end-to-end data or real-time media transmissions over an internet is disclosed. A media stream being transmitted to the internet is channel coded at the edge of the internet in order to free upstream bit rate for use in source coding the media. The channel coded media stream may then be decoded at a remote edge of the internet to recover lost packets.

A method for selecting an operating mode for a frame-based communications network consisting of a plurality of stations attached to a transmission medium. The plurality of stations include both a first type station and a second type station. The first type station is capable of transmitting and receiving first protocol frames in accordance with a first protocol. The second type station is capable of transmitting and receiving both first protocol frames and second protocol frames in accordance with a second protocol. The first protocol and the second protocol each use different signals on the transmission medium. The first type station is not capable of reliably detecting second protocol frames. The first protocol has a first protocol frame format containing at least two reserved bits in a first protocol frame header which are ignored in received frames by first type stations and always sent with a same fixed value by first type stations. The first protocol frame format is redefined to provide an updated first protocol frame header wherein two reserved bits in the first protocol frame header are allocated as a mode selection indicator field in the updated first protocol frame header. The mode selection indicator field has meaning for second type stations.

A method for controlling errors in a wireless link layer using a simultaneous multiple copy scheme and an adaptive forward error correction (FEC) scheme in a wideband wireless communication is provided. The method for controlling errors in a link layer in wideband wireless communication using an automatic repeat request (ARQ) scheme, in which a wideband wireless channel is used for communication between a first node and a second node, includes the steps of (a) estimating the error ratio of a forward (a direction in which a cell is transmitted from the first node to the second node) channel using the state of a backward (a direction in which a cell is transmitted from the second node to the first node) channel, and transmitting a cell, in which a forward error correction (FEC) code having an encoding ratio that varies depending on the estimated error ratio is included in a protocol data unit (PDU) of a wireless link layer, through the forward channel and (b) re-transmitting the copy of a cell transmitted in the step (a), when feedback information that indicates that an error exists in the cell transmitted in the step (a) is received through the backward channel. It is possible to reduce the number of times of re-transmission by improving the probability of correcting forward errors using more error controlling bits as the state of the channel is worse and to minimize the waste of resources using less error controlling bits as the state of the channel is better, to thus obtain the optimal performance and guarantee the minimum delay time.

A method for dynamic adjustment of downlink/uplink resource allocation ratio in a long-term evolution (LTE) time division duplex (TDD) system is disclosed. The method includes replacing at least one of an uplink subframe and a downlink subframe with a mute subframe in a subframe pattern, indicating a first downlink/uplink resource allocation ratio. Thereafter, the mute subframe is replaced with either the uplink subframe or the downlink subframe to form another subframe pattern. The subframe pattern including the mute subframe is obtained from a lookup table, such that the replacing the mute subframe results in the other pattern. A data transmission in accordance with the other subframe pattern, indicating a second downlink/uplink resource allocation ratio, may be scheduled. Hybrid Automatic Repeat-request (HARQ) processing may be implemented after the at least one of the uplink subframe and the downlink subframe is replaced with the mute subframe in the first subframe pattern.

A portable device, such as a mobile terminal or user equipment, for encoding uplink acknowledgments to downlink transmissions. The portable device includes a receiver configured to receive a plurality of data blocks, such that each of the data blocks include an associated cyclic redundancy check (CRC), and a processor configured to determine received status for each of the data blocks by checking the CRC of each of the data blocks. The portable device further includes a transmitter for transmitting a response sequence which indicates the received status of all of the data blocks.

A method and apparatus for efficiently transmitting channel quality information in an OFDM communication system using dynamic channel allocation and adaptive modulation, and determining parameters required for time-division channel quality information transmission in an asynchronous CDMA communication system are provided. In the OFDM communication system in which a plurality of subcarriers are allocated to a plurality of UEs, the subcarriers are divided into a plurality of subcarrier groups each having at least one subcarrier. Each of the UEs determines and transmits the channel quality information of each of the subcarrier groups according to predetermined transmission parameters at transmission time points that do not overlap with those of other UEs. A Node B dynamically allocates the subcarriers to the UEs and their corresponding modulation schemes according to the channel quality information.

A forward link device of a multicarrier CDMA communication system with an overlay scheme in which a multicarrier system and an IS-95 system share same frequency bands. In the forward link device, four encoders encode input data of corresponding rates with a 1/3 coding rate, respectively. A first repeater repeats two times full rate symbols output from the first encoder, and second to fourth repeaters repeat symbols output from the second to fourth encoders, respectively, according to a predetermined number of times, to match the number of corresponding output symbols to the number of full rate symbols. First to fourth interleavers interleave the symbols output from the first to fourth repeaters, respectively, to uniformly distribute the symbols of the same data bit to the carriers.

A technique for streaming digital video content to a client involves providing a new stream of digital video content to the client using forward error correction (FEC) for a limited initial period and then ending the use of FEC after the limited initial period has ended. In an embodiment, during the limited initial period, the digital video content is provided to the client at a rate that is slightly higher than the playout rate in order to allow a client buffer to accumulate digital video content. FEC continues to be used until the client buffer is sufficiently populated such that lost or damaged frames can be retransmitted to the client before the corresponding digital video content is needed for playout. Once the client buffer is sufficiently populated, FEC is ended and retransmission is used to maintain the quality of the streamed digital video content.

A method of and a system for controlling low power radio frequency activity of terminals, including a method of selecting and activating a wireless terminal. A signal, including a transmission indication, is transmitted by a first terminal. A second terminal receives the signal a number of times and compares the received transmission indications with predetermined indication values. When the comparison shows that a predetermined number of satisfactory transmission indications have been received by the second terminal, the second terminal commences transmission. The transmission indication can be messages having tail portions with a preselected set of states.

To address the need to convey ACK/NACK information in a manner that conserves system and signaling resources, embodiments of the present invention employ a Node-B transmitting on two types of ACK/NACK broadcast channels (501, 502), one type for received uplink data that was scheduled by the Node B and the other type of broadcast channel for received uplink data that was not scheduled by the Node B. Other embodiments of the invention employ a Node-B transmitting on two types of broadcast channels, one type of broadcast channel for received uplink data that comes from non-SHO users and another type of broadcast channel for received uplink data that comes from non-scheduled users or comes from scheduled SHO users. In addition, ACK/NACK information is scheduled (800) into the available broadcast channel time slots in accordance with a transmission priority that is determined by a scheduler.

The present system comprises a transmitting apparatus for digital broadcast which includes an original signal generating section, delaying section, information amount reducing section, and transmitting section. A receiving and reproducing apparatus for digital broadcast includes a signal reception front stage unit for receiving a high quality signal and a low quality signal, mode determining section and reproducing section composed of a delaying section and selecting section for selectively reproducing the high quality signal and the low quality signal. By employing time diversity, the transmitting apparatus sends the low quality signal having a smaller bandwidth and the high quality signal so that the low quality signal has a preceding time lag relative to the high quality signal, and the receiving apparatus reproduces broadcasting programs. Utilizing the frequency band for broadcast effectively, many broadcasting programs can be increased, and the investment for providing a gap filler can be minimized.

A mechanism for performing remote direct memory access (RDMA) operations between a first server and a second server. The apparatus includes a packet parser and a protocol engine. The packet parser processes a TCP segment within an arriving network frame, where the packet parser performs one or more speculative CRC checks according to an upper layer protocol (ULP), and where the one or more speculative CRC checks are performed concurrent with arrival of the network frame. The protocol engine is coupled to the packet parser. The protocol engine receives results of the one or more speculative CRC checks, and selectively employs the results for validation of a framed protocol data unit (FPDU) according to the ULP.

A method of synchronizing data transmission between a host computer system and a transmitter across an interface with variable delay or latency. The host computer system marks transition frames between successive transmission intervals and transfers the outgoing frames across the variable interface to the transmitter. The transmitter enqueues outgoing frames into one or more FIFO transmission queue(s) and processes the enqueued frames as appropriate for the communication protocol in use. Marked frames are detected as they reach the head of the appropriate transmit queue. In particular, while bypassing is not active, the transmitter transmits unmarked frames until the end of the current interval, or until there is insufficient time in the interval to transmit another frame or until a marked frame is detected. While bypassing is not active, the transmitter terminates transmission from the transmit queue when a marked frame is detected during each interval. While bypassing is active, the transmitter discards unmarked frames without transmission until a marked frame is detected. During each interval, the transmitter activates bypassing if a marked frame has not been detected and deactivates bypassing if a marked frame is detected while bypassing is active. The transmitter enables queue mark operation if a marked frame is detected while queue mark operation is not enabled. The transmitter increments a bypass counter each time an interval ends without detecting a marked frame, and disables queue mark operation if the bypass counter reaches a predefined limit.

A method and apparatus for protecting and authenticating wirelessly transmitted digital information using numerous techniques. The apparatus may be a wireless orthogonal frequency division multiplexing (OFDM) communication system, a base station, a wireless transmit/receive unit (WTRU), a transmitter, a receiver and/or an integrated circuit (IC). The wireless OFDM communication system includes a transmitter which steganographically embeds digital information in an OFDM communication signal and wirelessly transmits the OFDM communication signal. The system further includes a receiver which receives the OFDM communication signal and extracts the steganographically embedded digital information from the received OFDM communication signal.

A communication node of the present invention automatically transmits original and duplicate packets over different paths in a communications network to improve delivery reliability of the packet and to decrease packet delivery time. A packet is typically marked for reliable transmission by the application layer of a source node, while a routing agent module within the node IP layer processes the marked packets. The marked packets are transmitted over redundant (e.g., primary and secondary) network paths from the source node to the destination node. The primary path is usually the shortest path between the source and destination nodes, while the secondary path is selected to avoid overlap with the primary path. The application or transport layer of the destination node filters or removes plural copies of received packets.

A random access channel transmission method in which a user terminal selects a preamble pattern from among a plurality of known preamble patterns and transmits that preamble pattern to a base station, where that transmission method comprises: a step of dividing a cell into a plurality of areas, and setting one or more preamble patterns and the number of repetitions for transmitting the preamble pattern for each area; and a step wherein a user terminal that exists in an are close to the base station transmits a specified preamble pattern one time, and a user terminal that exists in an area far from the base station transmits another specified preamble pattern a plurality of times.

In a UMTS wireless communication system, when the packet size on the enhanced dedicated physical data channel (E-DPDCH) on the uplink from a UE to a NodeB reaches a converged default packet size, the corresponding dedicated physical control channel (E-DPCCH) is turned off. The NodeB uses the default packet size to decode the frame received on the E-DPDCH using each possible redundancy version. Alternatively, the E-DPCCH is turned off and a new transmission flag is transmitted by the UE only when a new frame is transmitted by the UE. NodeB then uses the presence or absence of that flag in conjunction with the absence of E-DPCCH to determine which redundancy version is to be assumed in decoding the frame received on E-DPDCH.

The invention discloses a duplication transmission configuration method and device and a duplication transmission method and device. The duplication transmission configuration method comprises the steps of determining each radio bearer of a terminal; and carrying out duplication transmission configuration for each radio bearer. The duplication transmission method comprises the steps that the terminal receives the duplication transmission configuration carried out at a network side; and carrying out duplication transmission according to the configuration. Through adoption of the methods and the devices, the duplication transmission can be applied flexibly for different bearer characteristics; the high reliability provided by the duplication transmission can be obtained; moreover, the utilization efficiency of radio resources can be improved; and resource waste is avoided; and air interface control signal costs are reduced.

Transmission methods for multicast messages and for signaling message responses thereto in communication systems supporting a multicast mode provide that a number of retransmissions of a multicast message may be changed based on a number of receivers of the message. Signaling messages to the multicast message may be transmitted in response to a fixed number of multicast message transmissions, and receivers that have not received the multicast message after the fixed number of transmissions may request further retransmissions up to an additional given number of times. Further, signaling messages may be transmitted at different times or staggered based on a radio condition of the receivers. For example, a first multicast message may be transmitted, and responses from groups of receivers may be listened to for a given period, after which one of a next multicast message and a portion of the first multicast message may be transmitted to the groups.

A system and method for mapping radio-frequency (RF) noise, and estimating channel quality in a multi-channel ultra-wideband communication system is provided. One method includes placing a plurality of time bins within a plurality of time frames and assigning a plurality of UWB communication channels comprising selected time bins. RF noise amplitude data is then sampled from selected time bins. The sampled RF noise amplitude data from the time bins is then averaged, thereby obtaining an average RF noise amplitude in each of the plurality of channels. The RF noise amplitude indicates the amount of RF noise present in a channel. The channels may then be ranked based on the characteristics of the RF noise.