391 results about "Robust Header Compression" patented technology

A robust IP / UDP / RTP header compression mechanism is provided to correctly reconstruct IP / UDP / RTP headers in the presence of packet losses and errors of unreliable networks. The header compression mechanism may include a compressor / de-compressor implemented for operation similarly to RFC 2508 but designed specifically to address robustness when employed in lossy and error-prone networks. The robust header compression scheme requires that, when a second-order difference of a field is non-zero, not only a particular RTP packet whose second-order difference is non-zero is sent with the new first-order difference, but also those following packets are also sent with the new first-order difference as long as: (a) a period pre-determined by factors such as channel characteristics (e.g., link round-trip time RTT / inter-packet separation); or (b) a positive confirmation is received by the compressor that the new first-order difference has been correctly received. In addition, during a period of communicating with the new first-order difference, if the corresponding RTP field changes again with non-zero second-order difference, the "new" first-order difference is combined with the original first-order difference such that the two first-order differences may be appended together as a simple means of communicating the two first-order differences reliably.

A demultiplexer 630 routes only one or more transport stream packets with a single packet identifier value to each physical layer pipe. A header compression unit 620 replaces the packet identifier of the transport stream packet with a short packet identifier of one bit length indicating at least whether the transport stream packet is a NULL packet.

Compression of inner headers of IPSec tunnel packets is achieved by storing an inner IP header and an inner protocol header in a context sub-table associated with the security association database entry at a destination tunnel device. IPSec tunnel packets having compressed inner headers may be identified by the LSBs of the SPI number in the IPSec header. The SPI number may also identify whether the IPSec tunnel packet is a TCP packet. A portion of padding in the encapsulated portion may identify a particular context sub-table used for decompressing the inner headers. The context sub-table may be updated as portions of the inner headers change.

A method, a telecommunications node, and a Protocol for Carrying Authentication for Network Access (PANA) Authentication Agent (PAA) of an IP-based network such as a CDMA2000 telecommunications network are provided for negotiating packet data header compression mechanisms. A first and second node, which may be, for example, a Packet Data Serving Node (PDSN) and a Mobile Node (MN) are first involved in a discovery phase. Then the PDSN sends a PANA Start-Request message to the MN with a list of supported header compression mechanisms. The MN receives the PANA Start-Request message with the list, and selects one or more supported mechanism from the list. The MN then responds back to the PDSN with the selected one or more header compression mechanisms via a PANA Start-Answer message. The PDSN stores the selection of the header compression mechanisms, authenticates the MN, possibly in combination with an Authentication, Authorization, and Accounting (AAA) server, and if the authentication is successful, allows the start of a data session using the selected header compression mechanism(s).

A compression context for a plurality of packets is established with a receiving device. Each of these packets is associated with one or more reliable multicast protocols, such as the Layered Coding Transform (LCT) protocol, the Asynchronous Layered Coding (ALC) protocol, the FLUTE protocol, the MUPPET protocol, and the NACK-Oriented Reliable Multicast (NORM) protocol. Upon establishment of the compression context, a compressed packet is generated for one of the plurality of packets and transmitted to the receiving device. The compressed packet has a reduced number of bits in its header. Upon receipt, the receiving device decompresses the compressed packet based on the compression context.

A UMTS (Universal Mobile Telecommunications System) core network supports a compression framework that provides for header compression of General Packet Radio Service Tunneling Protocol (GTP)-Encapsulated Packets. In particular; the GTP / UDP(User Datagram Protocol) / IP(Internet Protocol) header is compressed. In addition, the UMTS core network also supports RTP(Real Time Protocol) / UDP / IP header compression independent of the GTP / UDP / IP header compression.

Some embodiments relate to a network comprising two RBridges connected by a link where the two RBridges are not the ingress and egress RBridge for said frames, wherein said RBridges automatically exchange information as to their support of hop-by-hop reversible frame aggregation, reversible header compression, and reversible data compression, and wherein if both RBridges support any or all of these features in the same fashion, one or more of said features are automatically applied to appropriate frames at the transmitting RBridge and removed at the receiving RBridge, increasing the throughput of the link.

A method for communicating video data on a wireless channel in a packet-switched network includes the steps of operating at a wireless terminal a compression in packets on the video data during a video coding operation, detecting wireless channel conditions and adapting control parameters of the video coding operation to the detected wireless channel conditions. The compression operation is a robust header compression operation and the step of adapting control parameters of said video coding operation is performed in dependence of information about the wireless channel conditions detected on a feedback channel made available in a decompression step associated with the compression operation.

The invention concerns the bit error resilience of an IP protocol stack based on a secure link layer, in which packet flows are header compressed according to a suitable header compression standard. According to the invention, by analyzing each packet at the link layer it can be determined whether the packet is a full header packet, in which case the link layer checksum evaluation is used as normal for discarding faulty full header packets, or a header compressed packet in which case the link layer checksum evaluation is ignored and the packet is propagated upwards in the protocol stack. This solution not only opens up for more intelligent higher-level handling of faulty header compressed packets, but also solves the problem of properly protecting full header packets at the link layer. In order to compensate for ignoring the link layer checksum evaluation for header compressed packets, header protection is introduced at the header compression level of the link layer by using one or more local checksums. The invention is particularly applicable to delay-sensitive real-time data such as compressed voice or video.

A method for communicating video data on a wireless channel in a packet-switched network includes the steps of operating at a wireless terminal a compression in packets on the video data during a video coding operation, detecting wireless channel conditions and adapting control parameters of the video coding operation to the detected wireless channel conditions. The compression operation is a robust header compression operation and the step of adapting control parameters of said video coding operation is performed in dependence of information about the wireless channel conditions detected on a feedback channel made available in a decompression step associated with the compression operation.

A mobility header compression method and system for an IPv6-based LoWPAN is provided for supporting IPv6 mobility to the IPv6-based LoWPAN checks a packet carrying data and a first and a second headers containing transmission information about the data to determine whether the second header contains a compressed Internet Protocol version 6 (IPv6) information. When the second header contains a compressed IPv6 information, ands followed by a mobility header, a mobility support-indicative field of the first header is set to indicate that the second header is followed by the mobility header and the rest of the fields of the second header are compressed except for the mobility header-indicative field. A mobility information-indicative field of the mobility header is set to indicate inclusion of mobility information; and the rest of the fields of the mobility header are compressed except for the mobility information-indicative field.

A system and method for ATM header compression for DSL links is provided. One embodiment, among others, for compressing ATM headers for communication across an ATM network involves transmitting an initial full ATM header to a receiver in the ATM network. Thereafter, when data payloads are available for transmission, the ATM header that corresponds to the data payload is compressed by either a differential technique, dictionary technique, or a multi-cell technique. The compressed ATM header and the data payload are then communicated over the ATM network to the receiver, wherein the receiver is enabled to interpret the compressed ATM header accordingly. By compressing the ATM header, a greater number of ATM cells may be communicated in the ATM network than if the ATM header were communicated in an uncompressed format.

The method provides buffer status reporting for the transmission of uplink data from a wireless device (10) to a base station (20). User packets (50), each including a respective header, are stored in a first buffer (56) of the wireless device. The user packets taken out of the first buffer are converted into data units (60) written to a second buffer (81). The conversion includes header compression applied to the headers of the user packets depending on feedback information received from the base station. The wireless device transmits to the base station data units read from the second buffer and a buffer status report containing information on an amount of data to be transmitted from the wireless device. This information takes into account an amount of data stored in the first buffer.

An improved aggregation scheme for wireless multi-hop mesh networks is disclosed. An aggregator at each node operates to merge VoIP packets at an ingress / source node with a forced delay, but at an intermediate node aggregated packets are either sent directly to their destination or to the next hop without deaggregation. A novel compression mechanism for compressing and decompressing the aggregated packets is also disclosed.

A compression context for a plurality of packets is established with a receiving device. Each of these packets is associated with one or more reliable multicast protocols, such as the Layered Coding Transform (LCT) protocol, the Asynchronous Layered Coding (ALC) protocol, the FLUTE protocol, the MUPPET protocol, and the NACK-Oriented Reliable Multicast (NORM) protocol. Upon establishment of the compression context, a compressed packet is generated for one of the plurality of packets and transmitted to the receiving device. The compressed packet has a reduced number of bits in its header. Upon receipt, the receiving device decompresses the compressed packet based on the compression context.

A method and system for communicating header compression layer control messages. Header compression control messages are generated by a header compression layer and are sent through at least one link layer data packet by a link transport communications protocol layer to a remote receiver. The link transport communications protocol layer monitors receipt of link layer data packet acknowledgements that are received from the link transport communications protocol layer of the remote receiver for the at least one link layer data packet. The link transport communications protocol layer determines successful transmission of the header compression control message and provides, to the header compression layer, an indication of successful header compression control message transmission.

A method of generating an aggregate frame having a header unit, which carries MAC-header information applicable to one or more data units of said aggregate frame. Since each data unit of the aggregate frame no longer needs to carry the full MAC-header information, the overhead associated with the MAC header can be significantly reduced. At the receiver, the full MAC header corresponding to the data unit is reconstructed by (i) matching the appropriate header and data units to one another and (ii) combining the information present in the header unit and the compressed header portion of the data unit. Embodiments of the present invention are capable of improving the data throughput, for example, in an entertainment network having paired source and destination devices (e.g., a DVD player and an LCD screen) with a relatively large amount of data streamed from the former to the latter.

The invention is related with network communication, in particular wireless networking. In order to improve bandwidth utilization, a header compression protocol is implemented in most wireless network systems, such as robust header compression ROHC for WLAN systems. When using multicast groups for data communication problems with ROHC are related with relative late initiation of stations that newly enter the multicast group. The invention proposes an improved state machine for the compressor in order to overcome this drawback. It is also proposed an improvement for the decompressors which omit sending positive acknowledgements in order to further improve compression efficiency. The invention also concerns an accordingly improved method for the exchange of data packets in a network of distributed stations.

A method is disclosed for transmitting and receiving packetized data having multiple protocol headers in a packet data communication system. An operating state of a network is determined, and a period for transmitting a full packet is decided according to a result of the determination. Full packets having uncompressed headers are transmitted during periodic transmission times according to the decided full-packet transmission period, and compressed packets are transmitted in other transmission times. If the operating state of the network is decided to be a congested state according to an average packet retransmission ratio produced in a period for measuring the operating state of the network, the full-packet transmission period is set to “1”. A value of the full-packet transmission period in an unloaded state is twice a value of the full-packet transmission period in a normal state. Thus, the number of packets to be discarded due to packet loss can be reduced, and the efficiency of transmission can be improved by header compression technologies.

A method of reducing the bandwidth required to send traffic comprising a payload and a header originating in a first communications network over another communications network. The traffic is characterized by having header information from which a path from its source to destination can be predetermined, the method comprising: determining redundant header information which is not used for forwarding the traffic in the other network; replacing at least part or all of the redundant header information with compression information having a smaller bandwidth than the replaced header information; appending header information to the traffic to enable forwarding along the path in the other network to an egress node; at the egress node, processing the traffic to remove the appended header information and restore the replaced header information by removing the compression information and using the compression information to perform a look-up operation which retrieves the replaced redundant header information from a data store, wherein the same compression information is used to replace the same redundant header information for all the traffic having the same predetermined path; compression information comprising a dummy header data structure which conforms to a communications protocol arranged to be identifiable by traffic type in a carrier frame.

In one embodiment, a relationship is determined between radio link protocol (RLP) sequence numbers in received RLP packets and real-time protocol (RTP) sequence numbers in RTP packets decompressed from the received RLP packets. An RTP sequence number associated with a compressed RTP packet is determined based on the determined relationship and at least one of the RLP sequence numbers of the received RLP packet or packets forming the compressed RTP packet. An RTP time stamp may be determined in a similar manner.

33When an RRC procedure is combined with an SRNS Relocation procedure, a PDCP synchronization procedure is performed only if a next expected UL / DL Receive PDCP sequence number invalidity event is detected during the SRNS Relocation procedure. If no such invalidity event is detected, then no PDCP sequence number synchronization procedure is performed. If the RRC procedure is not executed in combination with the SRNS Relocation procedure, then the PDCP sequence number synchronization procedure is performed only if: (1) The RRC procedure causes the RLC entity that is used by the PDCP entity to be re-established; or, (2) The RRC procedure causes the header compression protocol used by the PDCP entity to be changed.

Provided is a content classifying section 203 for classifying and bundling to-be-transmitted contents on the basis of any piece of information of media kind, IP address, port number and session identifier. A packet header compressing section 204 carries out header compression on the transmission packet. Due to this, because contents can be packet-transferred with efficiency and excellent error resistance by the use of a communication and broadcast network, it is possible to realize, even on the Internet for broadcast in a broadcast form, a quality broadcast free of image or sound discontinuity as the terrestrial-wave TV broadcast.

A packet compressor 12 operates under a reliable mode or an optimistic mode. A mode determination unit 31 counts the number of ACK packets or NACK packets received by a unit time X by an ACK / NACK packet receiver 14. When the counted number of NACK packets is larger than a predetermined value Y, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the reliable mode. When the counted number of ACK packets is larger than a predetermined value Z, the mode determination unit 31 switches the operation mode of the packet compressor 12 to the optimistic mode.

A method of creating a service flow for ROHC in a control station is disclosed, which can establishes a ROHC channel between ROHC entities, the method comprising obtaining a first ROHC parameter from a ROHC entity of the control station, upon receiving a subscriber profile to which ROHC is applied; and transmitting a first message including the first ROHC parameter for requesting the creation of service flow to a mobile station related with the subscriber profile and a base station performing a dynamic service addition (DSA) procedure through the use of a second message including the first ROHC parameter.

A demultiplexer 630 routes only one or more transport stream packets with a single packet identifier value to each physical layer pipe. A header compression unit 620 replaces the packet identifier of the transport stream packet with a short packet identifier of one bit length indicating at least whether the transport stream packet is a NULL packet.

The present invention relates to a method and an apparatus for relocating a header compression text, wherein the context updating properties of each individual header during the relocation process is disabled.