Matsushita Electric Industrial Co., Ltd.

Panasonic Corporation

Godo Kaisha IP Bridge 1

Carsten Burmeister

Rolf Hakenberg

Akihiro Miyazaki

Hideaki Fukushima

Daiji Ido

Jose Luis Rey

Thomas Wiebke

Koji Imura

Koichi Hata

Fernando Berzosa

Thomas Klinner

A data transmission apparatus for sequentially transmitting data in units of packets each containing transmission data to the receiving end, comprises: a reception unit for receiving the transmission data as an input signal; a packet formation unit for receiving the transmission data received, and forming an uncompressed packet in which predetermined transmission data is stored as uncompressed data, and a compressed packet in which at least a portion of transmission data that follows the predetermined transmission data is compressed and stored as compressed data; a reference information management unit for holding and managing, as reference information, information relating to the uncompressed packet formed by the packet formation unit; and a transmission unit for transmitting the respective packets formed by the packet formation unit, as a transmission signal, to the receiving end. The packet formation unit forms compressed data to be stored in a compressed packet, on the basis of the transmission data of the uncompressed packet and the reference information stored in the reference information management unit. Therefore, the number of packets to be discarded at the receiving end due to an error which has occurred in the radio section is reduced, whereby the quality of data transmitted in the transmission path including the radio section is improved.

Data transmission method, data transmission apparatus, data reception apparatus, and packet data structure

A data transmission apparatus for sequentially transmitting data in units of packets each containing transmission data to the receiving end. The apparatus including a reception unit receiving the transmission data as an input signal, a packet formation unit receiving the transmission data, and forming an uncompressed packet in which predetermined transmission data is stored as uncompressed data, and a compressed packet in which at least a portion of transmission data that follows the predetermined transmission data is compressed and stored as compressed data. The apparatus also including a reference information management unit holding and managing as reference information related to the uncompressed packet, and a transmission unit transmitting the packets formed by the packet formation unit. The packet formation unit forming compressed data to be stored in a compressed packet, based on the transmission data of the uncompressed packet and the reference information.

A data reception apparatus has a data reception section that receives data sent from a server through a communication link. A storage section stores the received data, and a play back section plays back the stored data. A requesting section requests the server to send data, corresponding to a certain period, at a rate equal to or more than a normal rate and lower than a rate set up by the communication link.

Data reception apparatus and data distribution system

A data transmission apparatus for sequentially transmitting data in units of packets each containing transmission data to the receiving end, comprises: a reception unit for receiving the transmission data as an input signal; a packet formation unit for receiving the transmission data received, and forming an uncompressed packet in which predetermined transmission data is stored as uncompressed data, and a compressed packet in which at least a portion of transmission data that follows the predetermined transmission data is compressed and stored as compressed data.

Apparatus and method for transmitting or receiving an uncompressed packet followed by compressed packets

A data transmission apparatus is provided for sequentially transmitting data in units of packets each containing transmission data to the receiving end, the apparatus including: a reception unit for receiving the transmission data as an input signal; a packet formation unit for receiving the transmission data received, and forming an uncompressed packet in which predetermined transmission data is stored as uncompressed data, and a compressed packet in which at least a portion of transmission data that follows the predetermined transmission data is compressed and stored as compressed data; a reference information management unit for holding and managing, as reference information, information relating to the uncompressed packet formed by the packet formation unit; and a transmission unit for transmitting the respective packets formed by the packet formation unit, as a transmission signal, to the receiving end.

Data transmission method for sequentially transmitting packets, data transmission apparatus, and data reception apparatus

A method of transmitting data packets, in particular a real-time or near-real-time data over an internet protocol (IP) network using a real-time protocol (RTP) for media data packets and a real-time control protocol (RTCP) for control data packets. Each protocol is allocated a fraction of the available transmission bandwidth. The method comprises the steps of determining the needed RTCP bandwidth based on known link parameters for an individual media session, transmitting control data packets using the needed RTCP bandwidth and transmitting media data packets using the remainder of the available bandwidth.

Method of transmitting data packets using RTP and RTCP protocols

The radio control sectionnotifies a transmission rate that can be currently set up out of the radio channel transmission rates to the transmission rate decision section. The buffer monitoring sectionmonitors an amount of media data stored in the media reception bufferand when the amount of media data stored exceeds a threshold, the buffer monitoring sectionnotifies it to the transmission rate decision section. When information on the radio channel transmission rate from the radio control sectionshows that the radio channel transmission rate is well within the capacity and when monitoring information from the buffer monitoring sectionshows that the amount of data stored in the media reception bufferdoes not exceed a threshold, the transmission rate decision sectionoutputs a request for increasing the transmission rate of the media data to the control signal transmission/reception section. Thus, even if the maximum rate of the radio channel transmission rate that can be set up decreases due to deterioration of a communication environment, it is possible to prevent data play back from being interrupted.

Data reception device and data distribution system

A method of incrementing a receiver-initiated sending rate of data packets transmitted from a sender over a network receiver using Transport Control Protocol (TCP) comprising the step of sending an acknowledgement for received data packets from the receiver to the sender, wherein said acknowledgement contains an advertised window indicating the allowed sending bit rate and the step of increasing the advertised window by a maximum of one segment size per acknowledgement.

Optimised receiver-initiated sending rate increment

A method of performing Round Trip Time (RTT) measurement in a data packet receiver using a Transmission Control Protocol (TCP) for communication via a network with a sender, said method comprising the steps of sending an acknowledgement for a currently received data packet to the sender, measuring a first time instant when sending the acknowledgement, triggering at the sender the transmission of an expected data-packet, measuring a second time instant when the expected data packet is received, and calculating the round-trip time based on the measured first and second time instants.

Receiver-based RTT measurement in TCP

A packet transmission apparatus and method may divide data into a plurality of packets and transmit the packets. At a transmitting end, a context identifying number, identifying a data stream, is selected based on a relationship between a sequence number of a packet that is to be transmitted and a sequence number in an immediately preceding packet. A sequence number denoting an order of a packet divided on a per context basis is compressed, and transmission data assigned to the context identifying number with the compressed sequence number is transmitted on a per packet basis. At the receiving end, the compressed sequence number is decompressed on a per context basis. The context is separated based on the context identifying number, and data is combined by reassembling a packet into the order of a decompressed sequence number.

Packet transmitting/receiving apparatus and packet transmission method

A packet receiving method may include receiving a packet having either a compressed header or a noncompressed header. A packet received with a compressed header is decompressed to regenerate a non-compressed header for the packet. Error detection is performed to detect the presence of an error in a packet: (1) received with a noncompressed header, (2) having a regenerated non-compressed header, or (3) having a replacement non-compressed header. Part of the non-compressed header, in a packet having a regenerated non-compressed header, is replaced with previously stored non-compressed header information, which is known to be correct, when an error is detected in the packet so as to produce a replacement non-compressed header. A packet is output as a correctly received packet when no error is detected in the packet.

Packet receiving apparatus and packet transmission method

A method and apparatus for transmitting data packets in a packet stream wherein the data packets have compressed headers. Update packets containing data indicating a context used in compressing the headers, and non-update packets are transmitted. An irregular change of the packet stream is detected and at least one packet stream parameter is obtained. Dependent on the determined packet stream parameter, either an extended update packet or an extended non-update packet is transmitted, wherein the extended packets include information about the irregular change. In addition, the packet stream parameter is estimated and a safety factor is applied.

Method and apparatus for transmitting data packets

The present invention relates to a method and apparatus for transmitting video and/or audio data in a non-reliable and bandlimited network from a server to a client. The network may for instance be a wireless network. The data stream includes P-frames and I-frames. If during transmission a frame gets lost, the client notifies the server of the data loss when the next packet is received at the client correctly. The server then skips all the P-frames of the current P-frame sequence and continues the transmission with the next I-frame. Preferably, each packet has assigned a sequence number and the message from the client includes the sequence number of the currently received packet. The server may ignore a message from the client if the client's request for skipping the P-frames has already been executed. It is preferred to make use of the present invention for streaming MPEG data.

Data transmission in non-reliable networks

The present invention provides a method and apparatus for distinguishing between congestion and corruption losses during the transmission of data packets. The packet lost distinction is based on the evaluation of an error detection/correction code of each data packet and by detecting sequence numbers.

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Darmstadt, Germany

Carsten Burmeister