Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The radio control section 205 notifies a transmission rate that can be currently set up out of the radio channel transmission rates to the transmission rate decision section 207. The buffer monitoring section 208 monitors an amount of media data stored in the media reception buffer 209 and when the amount of media data stored exceeds a threshold, the buffer monitoring section 208 notifies it to the transmission rate decision section 207. When information on the radio channel transmission rate from the radio control section 205 shows that the radio channel transmission rate is well within the capacity and when monitoring information from the buffer monitoring section 208 shows that the amount of data stored in the media reception buffer 209 does not exceed a threshold, the transmission rate decision section 207 outputs a request for increasing the transmission rate of the media data to the control signal transmission/reception section 206.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: The invention relates to a method and apparatus for transmitting data packets over a channel wherein the data packets have compressed headers. After compressing a header using a context, a number of consecutive update packets are transmitted, each containing data indicating the context. According to the invention, the channel quality is determined and the number of update packets is set accordingly. The channel quality may be determined by measuring the block error rate or the signal-to-noise ratio. Alternatively, the channel quality may be estimated by evaluating whether a NACK message has been received. The total number of update and non-update packets transmitted during a context update phase may be set according to the Round Trip Time. The number of non-update packets may further be determined based on codec properties. The invention may advantageously be used over unreliable, e.g. wireless, channels.

Abstract: 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.

Abstract: 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.