CN1357189A - Robust delta encoding with history information - Google Patents

Robust delta encoding with history information Download PDF

Info

Publication number
CN1357189A
CN1357189A CN 00809083 CN00809083A CN1357189A CN 1357189 A CN1357189 A CN 1357189A CN 00809083 CN00809083 CN 00809083 CN 00809083 A CN00809083 A CN 00809083A CN 1357189 A CN1357189 A CN 1357189A
Authority
CN
China
Prior art keywords
field value
header
header field
difference
packet
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN 00809083
Other languages
Chinese (zh)
Inventor
K·斯万布洛
L·-E·荣松
M·德格尔马克
H·汉努
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Telefonaktiebolaget LM Ericsson AB
Original Assignee
Telefonaktiebolaget LM Ericsson AB
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Telefonaktiebolaget LM Ericsson AB filed Critical Telefonaktiebolaget LM Ericsson AB
Publication of CN1357189A publication Critical patent/CN1357189A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/04—Protocols for data compression, e.g. ROHC
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/16—Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/16—Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
    • H04L69/161—Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L69/00—Network arrangements, protocols or services independent of the application payload and not provided for in the other groups of this subclass
    • H04L69/22—Parsing or analysis of headers

Abstract

In the compression of header field values (12) to produce compressed header portions (17) of associated data packets (18) to be transmitted across a communication channel, there is included in each transmitted packet history information about delta values (ID) of a certain number of previous packets (18) in the transmission sequence. This makes the compression scheme more robust and tolerant of packet loss, because lost delta values (ID) can be reconstructed using the history information.

Description

Utilize the sane delta encoding of historical information
Invention field
Generally speaking the present invention relates to data packet communication, the header-compressed in the data packet communication.
Background of invention
Because the immense success of internet, on the link of all kinds, utilize Internet Protocol IP to become a large order (for example with reference to John Postel, " Internet Protocol ", is incorporated herein by reference it DARPARFC in September, 791,1981) here.But, because the wire link that Internet Protocol is designed to have very big bandwidth, the packet header of Internet Protocol is very big simultaneously, therefore adopts Internet Protocol on narrow band link, for example on cellular link, do like this, not simple thing always.If we consider Internet Protocol is used for real time data, normal speech for example, User Datagram Protoco (UDP) UDP (JohnPostel for example, " User Datagram Protoco (UDP) ", DARPARFC 768, in August, 1980, here it is incorporated herein by reference) and realtime transmission protocol RTP (Henning Schulzrinne for example, Stephen L.Casner, Ron Frederick and Van Jacobson, " RTP: real-time a kind of host-host protocol of using ", IETF RFC 1889, IETF audio/video transmission working group, here is incorporated herein by reference it in January, 1996) be used to the top layer of Internet Protocol.They need the header (20 of ITP, 8 of UDP, 12 eight hytes of RTP) of 40 eight hytes altogether in addition.Combine if we have only the normal speech of 15 to 20 eight hytes to use with frame size these header demands, header portion will take more than 70% of packet.For the new Internet Protocol that be about to occur the 6th edition (for example StevenDeering and Robert Hinden, " the 6th edition (Ipv6) standard of Internet Protocol ", RFC2460, IETF network work group, in December, 1998, here it is incorporated herein by reference), its header has 40 bytes, and this problem is more outstanding.When transmitting, dwindle header and will improve band efficiency, the saving funds by Radio Link.
This term of header-compressed (HC) refers to and makes the bandwidth of the requisite information of each jumping header in the point-to-point link as much as possible little.Header-compressed has been utilized such fact, and that is exactly that some fields of header in a stream do not change, and the variation of most of headers is all very little and/or foreseeable.Traditional header compression scheme has been utilized these facts, and only send static information at the beginning, the field that changes then sends (for example information of completely random) as no compressed value, perhaps send as the difference between the packet, and the latter is called difference (perhaps Delta) coding usually.When adopting the differential coding mode, a little less than compression scheme may be highly brittle, its performance depended on link-quality to a great extent.For example,, the phenomenon that packet is lost continuously will often occur on the link so, thereby quality is descended if data-bag lost is common thing on the link.
Traditional header compression/decompression method usually realizes with state machine, and keeping compressor reducer and decompressor states (context just) compatible is unusual difficult task.
Generally speaking, there are two kinds of different conventional arts to be used for the decompressor context is upgraded.First kind of technology adopts the mode that periodically refreshes, and what wherein send is pure header data.The advantage of this settling mode is the influence that its performance is not subjected to link two-way time (RTT), and reason is never to need to send any message to the such fact of compressor reducer from decompressor.This means that it also can work in simplex link.On the other hand, the periodic refresh mode has many shortcomings.For example, average that the header overhead will be very big, because many headers that refresh are greatly arranged, the great majority in them all are unnecessary.If the right and wrong that go wrong on the link usually see that the quantity of data packets of losing will be very big also.
Upgrading contextual other general fashion is only just to allow compressor reducer send refreshing information (just pure header data when decompressor sends request.Do needing a duplex link like this, but can reduce average header overhead, because do not carry out any unnecessary renewal.If two-way time is very short, this solution can also reduce owing to the link error incompatible quantity of data packets of losing of context state later on takes place.Significant disadvantages is the dependence to the duplex link channel, to the sensitiveness of the packet lost on the link, and very long when two-way time, when invalid context (and relevant refresh requests) occurring, to the dependence of a large amount of packets of losing continuously.
For all header compression scheme, their performance is described with two amounts.Compression efficiency is described the compressed degree of header.This can represent with average or maximum header size, also can represent with the two simultaneously, perhaps expression otherwise.Robustness is described the ability of loss of data incident on this scheme handle link.Can losing a packet make the header context incompatible and cause mass data packet loss subsequently?
Generally, the work of most traditional headers compression scheme gets all very good, but they require the error rate of link very low, and two-way time is very short.
At present, many different traditional headers compression schemes are arranged.In fact, they are not real different scheme, and are the different stages of development of same scheme.Suggestion the earliest (is seen Van Jacobson " compression-tcp of low-speed serial link/IP header ", IETF RDC1144, IETF network work group, February nineteen ninety, here it is incorporated herein by reference) only handle transmission control protocol and (see Jon Postel " transmission control protocol ", DARPA RFC761, in January, 1980, here it is incorporated herein by reference) stream, then can compress (Mikael Degermark for example later on to User Datagram Protoco (UDP) and RTP, " the IP header-compressed " of Bjorn Nordgren and Stephen Pink, IETF RFC 2507, IETF network work group, here is incorporated herein by reference it in February, 1999; " the IP/UDP/RTB header-compressed of low-speed serial link " of StevenCasner and Van Jacobson, IETF RFC 2508, IETF network work group, here is incorporated herein by reference it in February, 1999).Therefore we can say for real time data stream to have only a kind of scheme that header is compressed (seeing top Casner and Jacobson) today, it just carries out standardization by audio/video transmission working group in EITF at present, it is called CRTP here.
CRTP is with RTP/UDP/IP header-compressed to two eight hytes of 40 eight hytes, as long as these links are that this minimum size is mean value no better than reliably.CRTP adopts differential coding to three fields: CRTP serial number field; The id field of CRTP time mark field and internet protocol header.As mentioned above, CRTP adopts update request to upgrade invalid decompression context.
Also can adopt more generally scheme compression user data package/internet protocol header (seeing top Degermark or the like), it adopts the periodic refresh principle, the RTP header is then sending in the mode of not compressing subsequently, makes each packet increase by eight hytes of 12 headers.
As long as the link error rates of using is very low and/or two-way time is very short, CRTP just can work well.But Radio Link usually is not like this.Two-way time is generally all very big, causes before decompressor is received updating context message the mass data bag to be lost continuously.This all is unallowed for real-time audio and video usually.Whole data-bag lost rate also can be too big, and nobody thinks that can improve the Radio Link characteristic makes the result better.The decline of the error rate and two-way time all will be paid too many cost.So the robustness of CRTP is replaced by its fragility.
The present invention provides a principle, poor (Delta) value historical information of a certain number of packet that it sends before comprising in each packet that sends.Like this, it is more sane that compression scheme becomes, and more can bear losing of packet, because the poor information of losing can be come reconstruct with this historical information.
The accompanying drawing summary
Fig. 1 is an example of packet data transmitting station among the present invention.
Fig. 2 is an embodiment example of header compressor shown in Figure 1.
Fig. 3 is the operational instances that header compressor illustrated in figures 1 and 2 can be carried out.
Fig. 4 is an example of packet data receiving platform among the present invention.
Fig. 5 is an embodiment example of header decompressor shown in Figure 4.
Fig. 5 A is that the another one of embodiment shown in Figure 5 is selected.
Fig. 6 is the operational instances that the embodiment of header decompressor shown in Fig. 4～5A can be carried out.
Detailed Description Of The Invention
As mentioned above, lost data packets can cause the respective contexts state of header compressor inconsistent with the context state of header decompressor on the link.This inconsistent quality that can reduce communication service is because the packet that arrives when context is inconsistent can not pass to user application.If the header compress/decompress scheme can some packet of loss-tolerant and can not gone out the inconsistent situation of occurrence context, just can avoid quality the decline that is difficult to accept to occur.According to the present invention, suppose continuous in time packet, packet P-2, packet P-1, packet P or the like also can carry the information of header p-1, P-2 of front or the like, lose some packets so and also can not gone out the inconsistent situation of occurrence context by tolerance on link.In order in given packet information, to comprise the header information of the packet of front, can encode to total information, to avoid the making size of header become the big acceptance that it is to be difficult to.Like this, described as the front with below will describe in further detail, can in the header of given packet, comprise at least a portion historical information of earlier data packet head, not go out the inconsistent situation of occurrence context so that can in lost data packets, recover.The scope that is included in the historical information in the given header can be different, will describe in detail below.
Definition below will adopting in the following description.
Header decompression (HD) refers to from the process of the header compression signal reconstruct of header-compression process generation needed (compression) header information.
Loss (LCD) is the loss of packets parameter on the link between header-compressed and the header decompressor between header-compressed and decompression.If this parametric description adopts the coding principle suggestion that changes field, the continuous data packet loss of the maximum quantity that header compression scheme can be tolerated on this link.Certainly, this point requires in this scheme responsive more to loss without any other mechanism.
Loss (LBC) is that data packet stream arrives the loss that takes place before the header compressor before the header-compressed.This may be the loss of the other end that connects, and for example on the identical narrow band link that adopts same header compression scheme, but it also may be the loss on the link (core network) between them.Because the possibility of lost data packets is very little on a reliable like this link, compares its loss with narrow band link and can ignore.Why will simplify like this is to be exactly rational because require to be arranged to loss before the header-compressed identical with the value of losing between decompressing with header-compressed after doing like this.
On behalf of the packet in front, single Delta (ID) compare the variation of field.If the sequence number of a header is 42, the sequence number of previous header is 40, and the single Delta of packet 42 is exactly ID=2 so.
The Delta (AD) that adds up be a front K packet the ID value and, wherein K depends on that this scheme will remember that how strong the ability that changes have.Can see that from following description the K value has stronger robustness more greatly, thereby lose before can adapting to bigger header-compressed.
Coding delta values (ED) is encoded to two parameter I D and AD, thereby makes the enough parametric representations of they energy.
The sequence of data packet of introducing above continuous in time, packet P-2, packet P-1, packet P or the like, the ID of given header fields of P packet provide by following equation 1.
ID P＝S P-S P-1 (1)
Like this, the single Delta ID of P packet of this sequence PProvide with the difference between the respective field of its previous packet P-1 by the field of packet P.The sequence-number field of packet P and P-1 is appointed as S respectively in equation 1 PAnd S P-1
The above-described delta values that adds up can be defined as following equation 2 at packet P. AD P = Σ X = 1 K ID P - X , K ≥ 2 - - - - ( 2 )
Like this, the delta values AD that adds up PIn the representative data packet sequence before the packet P the corresponding single delta values of selected number (K) packet of emission and.
Shown in following equation 3, the single Delta of packet P and the delta values ID that adds up PAnd AD PCan encode with coding function f, produce the coding delta values, ED P:
ED P＝f(ID P，AD P) (3)
This coding delta values ED PBy subsequently as the emission of the part of header compression.At receiving terminal, the derivative f of f -1Be used to the delta values of encoding, recover single delta values and the delta values that adds up, shown in equation 4.
(ED P，AD P)＝f -1(ED P) (4)
The context that the present invention utilizes top equation 1 and 2 successfully to keep losing in the communication channel decompressor under the situation of a plurality of continuous data bags is kept effectively.For example, if the value of K is set to equal 2 in the top equation 2, so just can handle two this situations of packet of losing continuously at receiving terminal.If K equals 2 in the top equation 2, the delta values that adds up of packet P is provided by following equation 5 so.
AD P＝ID P-1+ID P-2 (5)
Below equation 6,7 and 8 represent respectively the energy enough header decompression schemes of the present invention decompress first, second and the 3rd estimated value.
S P＝S LAST+ID P (6)
S P＝S LAST+ID P+AD P-ID LAST (7)
S P＝S LAST+ID P+AD P (8)
In each equation in equation 6～8, first S LASTThe field value (in this example, being sequence number field) of that packet of the packet P front that representative is received in receiver (penult packet just), the ID in the equation 7 LASTRepresent corresponding ID value.Like this, from equation 6 as can be seen, if S LASTBe S P-1(not having lost data packets) just can expect can obtain the S shown in the equation 1 from equation 6 PValue.
But, if S LASTNot S P-1, just can not obtain S from equation 6 so PRight value, so can attempt estimation S for the second time from equation 7 PIf S LASTBe S P-2(packet P-1 is lost) just can expect can obtain S with equation 7 PRight value.Otherwise, will obtain an incorrect value with equation 7, so just the enough grades of energy are 8 to estimate S PIf S LASTBe S P-3(packet P-1 and P-2 are lost) so just can expect and utilize equation 8 can obtain S PRight value.Otherwise, can not obtain right value equally with equation 8.Can find from above discussion,, just can find right value S before packet P arrives with 3 times top continuous estimations as long as the packet of losing is no more than continuous two packets P
Get back to equation 7, as mentioned above, if only lose a packet, this equation just can provide correct value.In this case, the packet of Dao Daing will be packet P-2 at last, so S LASTAnd ID LASTBe S respectively just P-2And ID P-2, so just obtain following equation 7A.
S P＝S P-2+ID P+ID P-1 (7A)
Recognize S P-2Can represent with Fig. 7 B,
S P-2＝S P-1-ID P-1 (7B)
And with the S among this expression formula replacement equation 7A P-2, we obtain
S P＝S P-1+ID P (7C)
Equation 1 is compared and will find with equation 7C,, utilize equation 7 just can obtain correct result if the packet of receiving at last is packet P-2.
Get back to equation 8, as mentioned above,, can expect that this equation can provide S if lose 2 packets continuously PRight value.In this case, the packet of receiving at last will be P-3, so S LASTTo be S P-3With S P-3(obtaining) AD from equation 5 PSubstitution equation 8 just can access following equation 8A.
S P＝S P-3+ID P+ID P-1+ID P-2 (8A)
Recognize S P-3Can be expressed as following equation 8B.
S P-3＝S P-2-ID P-2 (8B)
And remember S P-2Can be expressed as top equation 7B, so S P-3Can be expressed as following equation 8C.
S P-3＝S P-1-ID P-1-ID P-2 (8C)
With S P-3Expression formula 8C substitution equation 8A just obtain following equation 8D.
S P＝S P-1+ID P (8D)
Top equation 1 is compared discovery with equation 8,, utilize equation 8 just can obtain correct result if the packet of receiving at last is packet P-3.
Following equation 9 is corresponding to equation 2 top under the situation of K=3.
AD P＝ID P-1+ID P-2+ID P-3 (9)
Add up this formula of Delta of utilization is being lost under the situation of three packets nearly continuously, and it is effective to keep the decompressor context with following equation 10～13.
S P＝S LAST+ID P (10)
S P＝S LAST+ID P+AD P-ID LAST-ID NEXTLAST (11)
S P＝S LAST+ID P+AD P-ID LAST (12)
S P＝S LAST+ID P+AD P (13)
Particularly, equation 10 hypothesis had been received packet P-1 (not having lost data packets) before packet P, equation 11 hypothesis had been received packet P-2 (losing 1 packet) before packet P, equation 12 hypothesis had been received packet P-3 (losing 2 packets) before packet P, equation 13 hypothesis had been received packet P-4 (losing 3 packets) before packet P.Like this, if S LASTBe exactly S P-1, equation 10 just can provide correct value S PIf, S LASTBe respectively S P-2, S P-3And S P-4, equation 11,12 and 13 just can provide correct value S P
Note the ID in the equation 11 NEXTLASTThe single delta values of the packet before the packet of receiving before the representative data bag P, the just packet received of penult.
In general, according to top with reference to equation 6～8 described modes, equation 10,11,12 and 13 representative respectively utilizes with the relevant appropriate value of receiving at last of receiving with penult of packet P, and example header decompression scheme of the present invention can carry out first, second, third and the 4th estimation to be attempted.
A kind of rare situation is arranged, and the estimation of equation 11 can not provide S when losing a packet in this case PRight value, although equation 11 should be able to provide right value under the normal condition.This situation is: packet P-4 is received; Packet P-3 loses; Packet P-2 is received; Packet P-1 is lost; Packet P is received.Equation 1 can not provide correct value in this case, because ID NEXTLASTIn fact be exactly ID P-4Rather than ID P-3, reason is that packet P-3 is not received, and is opposite with the hypothesis of equation 11, has only packet P-2 to be lost, packet P-3 is received.
This situation can be carried out the 5th estimation and be handled by after 4 estimation failures corresponding to equation 10～13.The estimation of this 5th is regarded above-described situation as basically and is not received packet P-2, like this, this situation is used as has lost three packets and handled, and has just lost packet P-1, P-2 and P-3.In this 5th estimation, can also utilize equation 13, but in current estimation, S P-4If (packet P-1, P-2 and P-3 really all lose, and it is just corresponding to the packet of receiving at last) is used as S LASTInsert.
Fig. 1 illustrates an embodiment example of the packet data transmitting station that can realize above-described example header squeeze operation among the present invention.Traditional communication application program 11 provides header information 12 and Payload information 13.Payload information can be handled according to traditional approach with Payload processor 15, and it exports Payload 16.Header information is offered header compressor 14, and header compressor header compression information produces the header 17 after the compression.Header 17 after Payload 16 and the compression comprises a packet 18.Receive this packet 18 with a traditional transmitter 19, and use well-known technology packet transmission to be gone out by the such Radio Communications Link of cellular communications networks.Packet data transmitting station shown in Figure 1 can be for example be operated in a fixed location in the cellular communications networks or the mobile radio launching tower.
Fig. 2 illustrates an example part of header compressor shown in Figure 1.Corresponding to the header information of required field, in this example above-described sequential value S P, be transfused to Delta encoder 21 and verification and generator 22.The Delta encoder carries out traditional Delta coding according to top equation 1, produces the S corresponding to packet P PSingle delta values ID PSingle delta values is transfused to buffer 24, and it is keeping a record of front K the single delta values of packet.Summing unit 25 connects with buffer, receives single Delta, also has the value of K, so that according to equation 2 needed those in the single delta values of front are added up, for packet P produces the Delta AD that adds up PEncoder 26 receives the single Delta ID of packet P PWith the Delta AD that adds up P, and their codings are become the coding Delta ED of packet P P
Verification and generator 22 utilize sequence number value S PProduce verification and (for example CRC and), verification just shown in Figure 2 and P.29 verification and with 20 coding delta values ED PMerge header compression field 28 of formation, represent sequence number S PThis header compression field 28 can be included in the header compression, and for example shown in Figure 1 17.
Though Fig. 2 explanation is the compression of an independent header fields, is understood that the field of other required header also can enough technology shown in Figure 2 be compressed.
Encoder 26 shown in Figure 2 is with single Delta ID PWith the Delta AD that adds up PBe transformed into the coding Delta ED after the merging PIn one example, can be the single Delta and the unique code value of each possible values combination distribution of Delta that adds up, these values can be determined according to the verification observed result.So encoder 26 can be used as for example look-up table, it has a plurality of codes, according to ID P/ AD PCombination establishment subscript.In some embodiments, can determine the Delta ED that encodes PModal value, these modal values can be encoded with the bit of relatively small amount, and ED POther uncommon value is then encoded with more relatively bit.
The exemplary operation that Fig. 3 key diagram 2 example shown header compressor embodiments can be carried out.Receive header fields information 31,32 produce verifications and.Calculate single Delta 33, calculate the Delta that adds up 34.Produce the coding Delta 35 according to single and the Delta that adds up.To encode Delta with verification and merging formation header compression field 36.
Fig. 4 illustrates an example of packet data receiving platform among the present invention.The enough well-known technology of tradition receiver 46 energy receive a reception version 18 ' of the sort of packet 18 of emission shown in Figure 1 from the such Radio Communications Link of cellular communication link.The version of receiving 18 ' comprises Payload version 16 ' and the header compression version of receiving 17 '.The Payload version of receiving 16 ' is transfused to Payload processor 45, and it can produce the Payload information of receiving 43 by enough conventional arts, inputs to conventional data packet data communication application 41.The header compression version of receiving 17 ' is provided for header decompressor 44, the header version of receiving is decompressed, and 42 the header information of receiving is offered communication application program 41.
Fig. 5 illustrates the part of header decompressor shown in Figure 4.In Fig. 5, the reception version of the coding Delta EDP among Fig. 2 shown in 20 is provided for decoder 51, and it can utilize equation 4 to produce corresponding to the single Delta of packet P and the Delta that adds up.Can be with having ID P/ AD PCombination subscript-ED PThe decoder that the look-up table of value is realized is with Delta AD PWith single Delta ID PExport to reconstructor 53, this reconstructor 53 can allow header fields estimate trial according to top equation 6～8 or equation 10～13.S PCurrent estimation S just P' export from reconstructor 55, offer verification and generator 56.
Verification and generator are from current estimation S P' produce a verification and, and 57 with this verification with input to a comparator 58, with the verification of generation and 57 and Fig. 2 in the original checksums shown in 29 and reception version 29 ' compare.If the verification that is compared, just thinks that this estimation is correct with identical, comparator provides an output 500, and it controls a linkage unit 59, so that provide estimation S from reconstructor P' give communication application program 41 as the header information of receiving.This correct estimation feeds back to reconstructor 53 simultaneously, as S LASTStore, when utilizing equation 6～8 or 10～13 to estimate trial, use next time for reconstructor.Receive new S LASTThe time, reconstructor can be with ID PBe displaced in the two-stage shift register 52, keep ID there LASTAnd ID NEXTLASTA log, be used for equation 6～8 or 10～13.
If the verification that produces with the verification of receiving in the comparator with different, comparator output 500 just notifies reconstructor once to attempt in addition, is for example utilizing equation 6 not attempt equation 7 after the success.If in the equation 6～8 (the perhaps equation in the another one embodiment 10～13) neither one can in comparator 58, obtain identical verification and, reconstructor 53 just can be exported a failure signal and give communication application program 41, illustrates that this header fields can not be by reconstruct exactly.
Though Fig. 5 has illustrated the decompression method of an independent header fields, be understood that other header fields also can enough technology shown in Figure 5 decompress.
In order to realize the estimation under the above-described special case, wherein equation 13 is repeated to use S P-4(it is corresponding to the penult packet of receiving) is used as S LASTReplace S P-2(in fact it is corresponding to the packet of receiving at last) inserts, and reconstructor shown in Figure 5 need be kept a log of two packet S values receiving at last, S LASTAnd S NEXTLASTFor example this can accomplish by adopting with register 52 similar two-stage shift registers shown in Figure 5.S LAST/ S NEXTLASTAn example 52A of register provides in Fig. 5 A.So above-described repeated use at the 5th estimation equation 13 can be described as with equation 14:
S P=S NEXTLAST+ID P+AD P (14)
Figure 16 has provided the operation that the example header decompressor part shown in Fig. 5 and Fig. 5 A can be carried out.In 61, the reception version of header compression field arrives.In 62, the coding Delta is deciphered, produce single Delta and the Delta that adds up.63, reconstructor is utilized in the equation 6～8 or 10～14 for example to be reconstructed and is attempted or estimation.64, from reconstruct estimation produce a verification and.If 65 verifications that produce and the verification that equals to receive and, just reconstruct estimated and accepts as header field value 66.If 65 verifications that produce with the verification of receiving with different, reconstructor is just carried out other reconstruct estimation (with the another one in the equation 6～8 or 10～14) 63, has carried out all trials (all equatioies just) up to identification in 67.If like this, just provide a failure signal 68.
Obviously, for this area terminating technical staff, above-described exemplary can be by realizing the header compressor of conventional data packet data transmission and receiving platform and software, hardware or the two the suitable modification of decompressor at an easy rate.
Equally, the present invention can be used in by diminishing narrow band link and carries out data packet communication, comprises the real time communication application, for example real-time audio and Video Applications.
Though describe exemplary of the present invention above in detail, this is not to limit the scope of the invention, and the present invention can enough various embodiments realize.

Claims (27)

1. a method is used to compress the current preamble field value, produces a header compression part of relevant current data packet, launches by communication channel, comprising:
Determine first difference between current preamble field value and the corresponding header field value, this correspondence header field value is relevant with the previous packet in the past that is arranged in a data packet sequence current data packet front, and this sequence of data packet is by described traffic channel; With
In partly furnish an explanation first difference and the information of second difference between the header field value also is described of header compression, these header field value are associated with first and second of the current data packet front in the described sequence former packets respectively corresponding to the current preamble field value.
2. what the process of claim 1 wherein provides step to comprise first and second difference to be encoded, produce the coded representation of first and second differences.
3. the method for claim 2, coding step wherein comprise according to first and second difference determines coded representation with look-up table.
4. the method for claim 1, the step that provides wherein comprises the 3rd difference of determining between the header field value, these header field value are corresponding to the current preamble field value, first packet and the 3rd data with current data packet front in this sequence are surrounded by the pass respectively, and the 4th difference between definite header field value, it is corresponding to the current preamble field value, respectively second of face and the 3rd data be surrounded by related, and with the 3rd and the 4th difference generation second difference of adding up.
5. the method for claim 1, comprise from the current preamble field value produce a verification and, and partly provide this verification and and information that first and second differences are described at header compression.
6. the communication channel that the process of claim 1 wherein comprises wireless communication link.
7. the header field value that the process of claim 1 wherein comprises a sequence number.
8. method is used for the header compression from the current data packet of communication channel is partly decompressed, and produces the header field value that needs, and comprising:
Partly obtain first information from header compression, first difference between the corresponding header field value of a required header field value and a packet by current data packet front in the sequence of data packet of traffic channel is described, described acquisition step comprises from header compression and partly obtains second information, second difference between the header field value is described, it is corresponding to required header field value, and first and second packet with current data packet front in the transfer sequence is associated respectively; With
The needed header field value of estimation on the basis of first and second information.
9. the method for claim 8, estimation step wherein is included on the basis of first and second information, and corresponding to needed header field value, packet with current data packet front in the transfer sequence is relevant, on the basis of the header field value of receiving before the current data packet, estimate needed header field value.
10. the method for claim 8, comprise from one of the coded representation of header compression extracting section receiving version, it represents first and second differences, is that the transmitting terminal in communication channel produces, described acquisition step comprises to be deciphered the reception version of coded representation, obtains first and second information.
11. comprising according to the reception version of coded representation, the method for claim 10, decoding step wherein determine first and second information with a look-up table.
12. the method for claim 8, comprise from the estimation of required header field value produce a verification and, the verification that produces at transmitting terminal from the header compression extracting section from required header field value and one receive version, compare to determine whether this estimation correct with the verification that produces with verification of receiving and version.
13. the method for claim 8, wherein communication channel comprises wireless communication link.
14. the method for claim 8, second difference wherein be third and fourth difference and, the 3rd difference wherein is the difference between the header field value, it is corresponding to the current preamble field value, first relevant with current data packet front in the transmitting sequence respectively with the 3rd packet, the 4th difference wherein is the difference between the header field value, and it is corresponding to the current preamble field value, and second of the front face is relevant with the 3rd packet respectively.
15. the method for claim 8, header field value wherein comprise a sequence number.
16. a device is used to compress the current preamble field value, produces the header compression part of current data packet, launches by communication channel, comprising:
Be used to receive an input of header field value;
A difference is determined device, connect with described input, be used for determining that the current preamble field value is with first difference between the corresponding header field value of the packet of sequence of data packet current data packet front that will be by the communication channel emission, and be used for second difference between definite header field value, it is corresponding to the current preamble field value, and first and second packets with current data packet front in this sequence are relevant respectively; With
An output determines that with described difference device connects, and is used to export the header compression part, comprises the information that first and second differences are described.
17. the device of claim 16 comprises an encoder, is connected described output and described difference is determined between the device, is used for first and second differences are encoded, and produces the coded representation of first and second difference at described output.
18. the device of claim 16, difference wherein determines that device can determine the 3rd difference between the header field value, it is corresponding to the current preamble field value, first relevant with current data packet front in this sequence respectively with the 3rd packet, also be used for the 4th difference between definite header field value, it is corresponding to the current preamble field value, respectively in front of face second relevant with the 3rd packet, described difference is determined that device can be added up third and fourth difference and is produced second difference.
19. the device of claim 16, comprise a verification and generator, connect with described input, be used to receive the current preamble field value, thereby produce a verification and, described verification and generator are connected with described output, header compression partly provide verification with and information that first and second differences are described.
20. the device of claim 16, communication channel wherein comprises wireless communication link.
21. the device of claim 16, header field value wherein comprises sequence number.
22. a device is used for the header compression of the current data packet received from communication channel is partly decompressed, and produces required header field value, comprising:
An input is used to receive the header compression part;
A reconstructor, connect with described input, be used to receive first information that partly obtains from header compression, illustrate that required header field value follows by first difference between the corresponding header field value of the packet of current data packet front in the sequence of data packet of communication channel emission, described reconstructor also is used for partly receiving second information from header compression, second difference between the header field value is described, it is corresponding to required header field value, and first and second packets with current data packet front in the transmitting sequence are relevant respectively; With
Described reconstructor is estimated needed header field value according to first and second information.
23. the device of claim 22, reconstructor wherein has an input, be used to receive a header field value, this header field value is corresponding to required header field value, and the packet with current data packet front in the transmitting sequence is relevant, receive that in the current data packet front described reconstructor can be estimated required header field value according to first and second information and in the header field value that the reconstructor input is received.
24. the device of claim 22, comprise a decoder, be connected between described input and the described reconstructor, one that is used for representing from described header compression part received code receives version, it represents first and second differences, be to produce at the transmitting terminal of communication channel, this decoder can be deciphered the reception version of coded representation, obtains first and second information.
25. the device of claim 22, reconstructor wherein has an output, be used to export estimation to required header field value, also comprise a verification and generator, connect with described reconstructor output, be used to receive described estimation, produce a verification and, this verification and generator comprise an output, be used to export described verification and, also comprise a comparator, connect with described input, be used for the verification that produces from described header compression part received communication channels transmit end from required header field value and one receive version, described comparator is connected with the generator output with described verification, be used for from it receive described verification and, the verification that described comparator can produce the verification of receiving and version with described verification and generator and comparing, whether correct with definite this estimation.
26. the device of claim 22, communication channel wherein comprises wireless communication link.
27. the device of claim 22, header field value wherein comprises sequence number.
CN 00809083 1999-06-18 2000-06-16 Robust delta encoding with history information Pending CN1357189A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US33555799A 1999-06-18 1999-06-18
US09/335,557 1999-06-18

Publications (1)

Publication Number Publication Date
CN1357189A true CN1357189A (en) 2002-07-03

Family

ID=23312282

Family Applications (1)

Application Number Title Priority Date Filing Date
CN 00809083 Pending CN1357189A (en) 1999-06-18 2000-06-16 Robust delta encoding with history information

Country Status (4)

Country Link
CN (1) CN1357189A (en)
AU (1) AU5862100A (en)
MX (1) MXPA01012521A (en)
WO (1) WO2000079764A1 (en)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2007065300A1 (en) * 2005-12-08 2007-06-14 Intel Corporation A header compress/decompress framework
CN100393064C (en) * 2004-06-21 2008-06-04 ***电信研究院 Group message header compression in IP telecommunication network system
CN101170487B (en) * 2006-10-25 2010-05-12 华为技术有限公司 Compression method and compression system and compression device in data stream multiplexing
CN101754275B (en) * 2002-08-14 2013-07-17 Lg电子株式会社 Bidirectional packet data transmission system and method
CN106187708A (en) * 2016-07-25 2016-12-07 西安岳达生物科技股份有限公司 A kind of preparation method of high-purity hydroxytyrosol
CN107861832A (en) * 2017-09-27 2018-03-30 深信服科技股份有限公司 Data verification method, device and readable storage medium storing program for executing

Families Citing this family (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1926282B1 (en) * 1999-10-14 2012-11-21 Nokia Corporation Method and system for compressing and decompressing packet headers
US6882637B1 (en) 1999-10-14 2005-04-19 Nokia Networks Oy Method and system for transmitting and receiving packets
US7539130B2 (en) 2000-03-28 2009-05-26 Nokia Corporation Method and system for transmitting and receiving packets
GB2376849B (en) * 2001-06-22 2003-08-27 Motorola Inc Method and apparatus for transmitting data
GB2386805B (en) * 2002-03-22 2004-05-26 Roke Manor Research Apparatus and method for compression of a signalling portion of a communications packet
KR100889864B1 (en) * 2002-08-14 2009-03-24 엘지전자 주식회사 Method and system for compressing and transmitting multimedia data
US7864701B2 (en) * 2005-03-31 2011-01-04 Intel Corporation Apparatus, system and method capable of decreasing management frame size in wireless networks
WO2007065458A1 (en) * 2005-12-07 2007-06-14 Siemens Home And Office Communication Devices Gmbh & Co. Kg Method, circuit arrangement and terminal for transmitting voice and/or video data via ip-based networks

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US9635140B2 (en) 2002-08-14 2017-04-25 Lg Electronics Inc. Bi-directional packet data transmission system and method
CN101754275B (en) * 2002-08-14 2013-07-17 Lg电子株式会社 Bidirectional packet data transmission system and method
US8848684B2 (en) 2002-08-14 2014-09-30 Lg Electronics Inc. Bi-directional packet data transmission system and method
US9635141B2 (en) 2002-08-14 2017-04-25 Lg Electronics Inc. Bi-directional packet data transmission system and method
US9635142B2 (en) 2002-08-14 2017-04-25 Lg Electronics Inc. Bi-directional packet data transmission system and method
CN100393064C (en) * 2004-06-21 2008-06-04 ***电信研究院 Group message header compression in IP telecommunication network system
US7773632B2 (en) 2005-12-08 2010-08-10 Intel Corporation Header compress/decompress framework
CN101326502B (en) * 2005-12-08 2012-07-18 英特尔公司 Compression/decompression frame for masthead of a newspaper
WO2007065300A1 (en) * 2005-12-08 2007-06-14 Intel Corporation A header compress/decompress framework
CN101170487B (en) * 2006-10-25 2010-05-12 华为技术有限公司 Compression method and compression system and compression device in data stream multiplexing
CN106187708A (en) * 2016-07-25 2016-12-07 西安岳达生物科技股份有限公司 A kind of preparation method of high-purity hydroxytyrosol
CN107861832A (en) * 2017-09-27 2018-03-30 深信服科技股份有限公司 Data verification method, device and readable storage medium storing program for executing
CN107861832B (en) * 2017-09-27 2020-11-13 深信服科技股份有限公司 Data verification method and device and readable storage medium

Also Published As

Publication number Publication date
AU5862100A (en) 2001-01-09
WO2000079764A1 (en) 2000-12-28
MXPA01012521A (en) 2002-07-02

Similar Documents

Publication Publication Date Title
CN1163046C (en) Robust header compression in packet communications
EP1173948B1 (en) Apparatus for transmitting/receiving bitstream in network and method thereof
CN101366261B (en) Method and apparatus for enhancing rohc performance when encountering silence suppression
US8718098B2 (en) Method for compressing and decompressing time stamp and equipment thereof
AU2001277483B2 (en) Header compression method for network protocols
KR101722719B1 (en) Backward looking robust header compression receiver
EP1415474B1 (en) Method and compressor for compressing packet timestamp information
CN1357189A (en) Robust delta encoding with history information
CN1510881A (en) Control traffic compression method
CN1593051A (en) Extension header compression
CN1156123C (en) Method and equipment for grouping transmission data
CN1645864A (en) Apparatus and method for header decompression
CN1522527A (en) Implicit packet type identification
Perkins et al. Dependency removal for transport protocol header compression over noisy channels
CN102342079B (en) Do not improve flow rate and reliably transmit the method and apparatus of the stream of the packet with header compression
CN1522526A (en) Apparatus and method for implementing text based compression using cache and blank approach
CN101453463A (en) Data packet packing, transmitting and receiving method for mobile multimedia broadcast system
CN1353895A (en) Method and device for digital data transfer
CN1611027A (en) Unequal error protection using forward error correction based on reed-Solomon codes
Boggia et al. ROHC+: A new header compression scheme for TCP streams in 3G wireless systems
CN101453465A (en) IP packet compression, decompression method for mobile multimedia broadcast system
CN101690072B (en) A method for repairing the window-based least significant bits decoding in the robust header compression
CN108737349B (en) Voice data packet processing method and device
Yang et al. Compression Techniques for VoIP Transport over Wireless Interfaces
Minaburo et al. Deployment of IPv6 robust header compression profiles 1 and 2

Legal Events

Date Code Title Description
C06 Publication
PB01 Publication
C02 Deemed withdrawal of patent application after publication (patent law 2001)
WD01 Invention patent application deemed withdrawn after publication