CN101237419A - Packet header compression method in air-space communication of aviation telecommunication network - Google Patents
Packet header compression method in air-space communication of aviation telecommunication network Download PDFInfo
- Publication number
- CN101237419A CN101237419A CNA200810101523XA CN200810101523A CN101237419A CN 101237419 A CN101237419 A CN 101237419A CN A200810101523X A CNA200810101523X A CN A200810101523XA CN 200810101523 A CN200810101523 A CN 200810101523A CN 101237419 A CN101237419 A CN 101237419A
- Authority
- CN
- China
- Prior art keywords
- header
- compressed
- local
- reference list
- transmit leg
- 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
Links
Images
Landscapes
- Compression, Expansion, Code Conversion, And Decoders (AREA)
Abstract
The invention provides a header compression method in an aeronautical telecommunication network air and ground communication, which is applied to the header compression of a connectionless network protocol grouping and respectively maintains a local header compression reference in a transmit leg and a receive leg; the header compression reference comprises a local header compression reference catalog number and a corresponding header compression item; when the transmit leg sends grouped data to the receive leg, the method comprises the following steps: according to the header compression item of the grouped data header, the transmit leg searches the local compression reference; the local header compression reference catalog number is used to compress the grouped data header; after the local header compression reference catalog number is compressed by using the least significant bit algorithm based on a window W-LSB, the grouped data is sent to the receive leg; after the receive leg receives the grouped data, the local header compression reference catalog number is restored according to the W-LSB algorithm; according to the local header compression reference catalog number, the local header compression reference is searched to obtain a header compression item corresponding to the local header compression reference catalog number; the grouped data header is restored.
Description
Technical field
The present invention relates to the aeronautical telecommunication network, relate in particular to the header compression method in a kind of air-space communication of aviation telecommunication network.
Background technology
Aeronautical telecommunication network (ATN) is the important component part of communication and navigation supervision/air traffic control system (ATCS) (CNS/ATM), is the basis of realizing navigation system of new generation.Because seven layers of traffic model that historical reasons, aeronautical telecommunication network have adopted International Organization for Standardization to formulate.Aeronautical telecommunication network mainly is made up of three subnets, that is: ground, ground communication subnet, air-ground dialogue subnet, absolutely empty communication subnet.
Data compression technique in the aeronautical telecommunication network is mainly used in the air-ground dialogue subnet.The earth-space communication subnet master of ATN is made up of very high frequency(VHF) (VHF) data chainning, aeronautical mobile-satellite communication (AMSS), secondary surveillance radar S mode data chain at present, the common trait of these wireless communication means is that bandwidth resources are limited, traffic rate is lower, only is 31.5kbps as the data communication rates of VHF.And in the protocol stack of ATN, in the earth-space communication of ATN, a typical communication packet size is about a hundreds of byte.And CLNP (Connectionless Network Protocol, connectionless network protocol) Fen Zu header, only standing part and address part just have 51 bytes, if add the part charge and the option part of grouping, whole C LNP header length will be above 70 bytes.This can cause great bandwidth waste in the transmission of the air-ground dialogue of ATN, bring more serious burden for the original just not enough air-ground dialogue of bandwidth.The reduction of being not only efficiency of transmission that excessive header brings, because the intrinsic unreliability of wireless channel, excessive header also can bring the increase of packet transmission failure probability, and this can increase the burden that network retransmits conversely again, further the bandwidth resources of consume valuable reduce network transmission efficiency.Therefore, ATN air-ground dialogue subnet needs the urgent data compression technique that solves, and reduces effective transmission time of grouping, improves channel utilization.
In header information, exist a large amount of information redundancies, it at first is the redundancy in the different bags, the different grouping that is same protocol has been carried a large amount of identical information, be the redundancy that continues between the bag then, correlation before and after promptly having between the field of the continuous bag in transport stream perhaps exists context dependence.According to the variation characteristic of field in the header, these fields can be taked the diverse ways compression.
Van Jacobson has proposed IP header compression protocol VJHC the earliest at TCP (transmission control protocol) agreement, i.e. RFC1144 (Request for Comments, Request for Comment).VJHC has utilized differential coding mechanism, promptly encodes with the difference between the adjacent packets, can be compressed to 4 bytes to tcp/ip header.But this coding method seriously relies on the context synchronized relation of grouping, and is therefore very responsive to the error of transmission on the link.
Perkins and mutka are at S.J.Perkins and M.W.Mutka, " Dependency Removalfor Transport Protocol Header Compression over Noisy Channels ", In Proc.OfIEEE International Conference on Communications (ICC), vol.2, Montreal, Canada, June 1997, among the pp.1025-1029 VJHC algorithm is improved, proposed a kind of to reduce the more healthy and strong compression algorithm that the header-compressed rate is a cost, in this algorithm, grouping serves as with reference to carrying out differential coding with a fixing frame, every component group all has oneself a reference frame, and obvious this algorithm has reduced the influence degree of transmission error to compression algorithm, but VJHC has reduced compression efficiency relatively.
RFC2508 has proposed CRTP (Compressed Real-Time Protocol, Real Time Compression agreement) header compression scheme.Using UDP (User Datagram Protocol, User Datagram Protoco (UDP)) verification and the time, CRTP can be with RTP (the Real Time Transport Protocol of 40 bytes, RTP)/UDP/IP header-compressed to 4 byte, do not use the UDP verification and the time, can be compressed to 2 bytes.RFC2508 relies on the response time back and forth of link, and losing of wrapping in response cycle will cause losing of subsequent packet.
RFC3095 has proposed a kind of healthy and strong header compression algorithm ROHC (Robust headercompression) mechanism.ROHC be a kind of can have healthy and strong on the link higher than long response time and error rate, effectively carry out the algorithm of header-compressed, can be applied to RIP (Routing informationProtocol, the route selection information agreement)/UDP/IP compresses class, UDP/IP compresses class and ESP (encapsulatingsecurity payload, ESP)/IP compresses class.RFC3095 relatively be fit to be applied to voice and video etc. have before and after the data flow of content relevance, but and be not suitable for being applied to air-ground dialogue in the aeronautical telecommunication network.
At document ATTF/5-IP/11, SUPPLEMENT TO HEADER COMPRESSION INMOBILE SUBNETWORK, Fifth Meeting of Aeronautical TelecommunicationNetwork (ATN), Transition Task Force of APANPIRG, in 2003, another kind of CLNP header compression algorithm has been proposed.Safeguard a compression dictionary at transmit leg and recipient, the list item in the compression dictionary is made up of version number, source address, destination address, the secure option of CLNP grouping, the corresponding sequence number of each list item.When new CLNP grouping arrives, transmit leg is match query list item in the compression dictionary at first, if find, then use this list item corresponding sequence number as a field in the new packet header, replace the content such as version number, source address, destination address, secure option in the original header, reorganize header format, like this, whole header has been compressed 40～50 bytes.And if can not find the list item of coupling, then transmit leg will be set up a new list item in the compression dictionary, content comprises version number, source and destination address and secure option, then a parameter that comprises this list item length and corresponding sequence number is inserted original CLNP grouping, and with this not compressed recipient that sends to that divides into groups.After the recipient receives this grouping, this parameter is extracted from the CLNP grouping, upgrade the compression dictionary of oneself.
This compression method can be with CLNP header-compressed to 6～11 byte, but also has very big further compression stroke.
Summary of the invention
The technical problem to be solved in the present invention provides the header compression method in a kind of air-space communication of aviation telecommunication network, and the excessive efficiency of transmission of bringing of header is low in the solution aeronautical telecommunication network communication process, the problem of waste system resource.
In order to solve the problems of the technologies described above, the invention provides a kind of header compression method, be applied to the compression of connectionless network protocol packet header, respectively safeguard a local header-compressed reference at transmit leg and recipient, wherein local header-compressed is with reference to comprising some, and every comprises local header-compressed reference list number and corresponding header-compressed item, and the header-compressed item is one or more parameters of packet header, when transmit leg sends to the recipient with grouped data, comprise following steps:
Transmit leg is searched local header-compressed reference according to the header-compressed item of grouped data header, after finding the local header-compressed reference list corresponding number with this header-compressed item, use this this locality header-compressed reference list compressed packet datagram header, use based on the least significant bit W-LSB compression algorithm of window should this locality header-compressed reference list number after, grouped data is sent to the recipient;
After the recipient receives grouped data, recover local header-compressed reference list number according to the W-LSB algorithm, number inquire about local header-compressed reference according to this this locality header-compressed reference list, obtain and this this locality header-compressed reference list number corresponding header-compressed item, recover the grouped data header.
Further, said method also can have following characteristics, and described transmit leg uses W-LSB compression algorithm and the local header-compressed reference list of decompress(ion) number to comprise following steps:
(a) respectively safeguard N with reference to base value transmit leg and recipient, promptly each is with reference to the i.e. local header-compressed reference list number of base value;
(b) transmit leg uses the W-LSB algorithm that local header-compressed reference list number is compressed, and a low level K bit of a transmitting locally header-compressed reference list number is specific as follows:
Transmit leg uses described N to come the calculating K value with reference to base value, and each with reference to base value v_ref, is determined the value of k_ref by following formula:
F(v_ref，k_ref)＝[v_ref-P，v_ref+(2
k_ref-1)-P]
F (v_ref, k_ref) be an interval section, number draw a k_ref according to reference base value v_ref and local header-compressed reference list to be compressed, guarantee local header-compressed reference list to be compressed number interval section F (v_ref, unique in k_ref), for each with reference to base value, all draw the k_ref of a correspondence, therefrom choose maximum k_ref then, i.e. the number of bits K of the needs transmission that draws of W-LSB algorithm, described P is an integer.
(c) recipient uses with reference to base value the K position bit that receives is carried out decompress(ion), recovers former local header-compressed reference list number.
Further, said method also can have following characteristics, if described local header-compressed reference list number continues to increase, gets P=-1; If local header-compressed reference list number remains unchanged or increases, get P=0; If the absolute value of local header-compressed reference list number and certain difference that often is worth is got p=2 in assign thresholds
K_ref-1-1.
Further, said method also can have following characteristics, described transmit leg sends N grouped data to the recipient, wherein comprise complete local header-compressed reference list number in the header of each grouped data, during grouped data of every transmission, wherein local header-compressed reference list number is kept in the variable sliding window of transmit leg with reference to base value as one, after the recipient receives this grouped data, wherein local header-compressed reference list number is kept at this locality as one with reference to base value, thereby obtains N with reference to base value.
Further, said method also can have following characteristics, described transmit leg obtains the some information that whether is continued use with reference to base value by feedback mechanism from the recipient, determine one with reference to base value when no longer the side of being received uses when transmit leg, transmit leg should be deleted from the variable sliding window of transmit leg with reference to base value.
Further, said method also can have following characteristics, and after transmit leg was merged into a grouping with the grouped data of segmentation, the segmentation option part in the cancellation header was compressed header again.
Further, said method also can have following characteristics, and described header-compressed item comprises protocol version, source address, destination address and secure option parameter value.
Further, said method also can have following characteristics, and transmit leg and recipient's local header-compressed is with reference to setting up in the following way:
Transmit leg is searched local header-compressed reference according to the header-compressed item of grouped data header, if when not finding corresponding local header-compressed reference list, transmit leg local header-compressed with reference in increase a new local header-compressed reference list number, this new local header-compressed reference list number is corresponding to the header-compressed item of this packet header;
Transmit leg should new local header-compressed reference list number inserts in this grouping, keeps the header of grouped data, and grouped data is sent;
After the recipient receives this grouping, extract the local header-compressed reference list of carrying in this grouping number and header-compressed item, this header-compressed item and local header-compressed reference list number are added into recipient's local header-compressed reference.
Further, said method also can have following characteristics, and transmit leg sends after will this new local header-compressed reference list number inserting option part in this grouping.
Further, said method also can have following characteristics, the recipient preserves the header of the grouping of carrying complete header compression of receiving at last, during transmit leg transmission grouping, when the header of grouping was the same with the header of the grouping of having transmitted, transmit leg was provided with no packet header position, after the recipient receives this grouping, if there is no packet header position, the complete header compression that the recipient preserves according to this locality recovers packet header.
The compression algorithm of using in the present invention and the existing air-space communication of aviation telecommunication network subnet is compared, and has cancelled the part charge of grouping, thereby has cancelled the segmentation option of compression back packet header; At the air-ground dialogue two ends default Lifetime is set, has cancelled this field in the header; Having introduced the W-LSB algorithm number further compresses local header-compressed reference list; By being set, the NHD position unconverted header is carried out the replacement of a byte.After using this method, the CLNP header can be compressed into 1～3 byte, and with respect to 6～11 bytes of original standard, compression ratio has improved a lot.
Description of drawings
Fig. 1 is a header-compressed schematic diagram of the present invention;
Fig. 2 is a header data form schematic diagram;
Fig. 3 is the header format schematic diagram after the present invention compresses;
Fig. 4 is that transmit leg of the present invention and recipient divide into groups to consult schematic diagram;
Fig. 5 is a header-compressed flow chart of the present invention;
Fig. 6 is that the present invention uses LSB compression algorithm flow chart;
Fig. 7, Fig. 8, Fig. 9, Figure 10, Figure 11 are respectively the message header compression Propagation Simulation result of message length when being 100,200,300,400,500 bytes, and wherein each picture in picture (a) be the message transmissions success rate, and scheming (b) is the message mean transit delay.
Embodiment
Safeguard a method of compressing dictionary at transmit leg and recipient in the prior art, also there is further compression stroke, part charge such as grouped data, if the segmentation of cancellation grouping, then can further compress 2～6 bytes, in addition, the list item sequence number of compression dictionary can also further be compressed, thereby further improves the compression efficiency of packet header.Therefore, the present invention proposes a kind of header compression method, has cancelled the segmentation of grouping, replaces former grouping life cycle life cycle with fixing grouping, and further compresses the sequence number of dictionary with the W-LSB algorithm.
The main thought of algorithm of CLNP header-compressed is among the ATN that the present invention proposes, the transmit leg and the recipient of grouping respectively safeguard a header-compressed catalogue or local header-compressed reference, the segmentation of transmit leg cancellation grouping, after the grouping of segmentation is reassembled as a grouping, compress with reference to header according to local header-compressed the grouping after the reorganization, further compress local header-compressed reference list number with the W-LSB algorithm again, and then the grouping after the compression given data link layer and send, after the recipient receives the grouping that the data link layer transmission comes up, at first recover local header-compressed reference list number by the W-LSB algorithm, again according to local header-compressed with reference to recovering the CLNP header, and then give network layer entities grouping and handle.
The contraction principle of CLNP header as shown in Figure 1, after original packet arrives transmit leg, at first choose suitable header-compressed catalog number (Cat.No.) (Packet Header CompressIndex) according to local header-compressed reference, perhaps choose suitable local header-compressed reference list number (Packet Header CompressLocal Reference, phclr), after original header was replaced by local header-compressed reference list number, the whole group side of being sent out sent to the recipient.After the recipient receives grouping, recover compressed packet header, then complete grouping is given the upper strata processing of protocol stack according to local header-compressed reference list.Therefore, this compression algorithm need be set up local header-compressed reference at the communication two ends and the local header-compressed reference at the two ends that keep communicating by letter synchronous.
The corresponding relation of local header-compressed reference list number and header-compressed item at first is described.Fig. 2 is the packet format that adopts the CLNP agreement, preceding nine standing parts that byte is a header, is address part from the 10th byte to n-1 byte, since 6 bytes of n byte is part charge, is the option part from n+6 byte to p byte, is the data that the grouping transport layer of carrying passes at last.
Changeless field has network layer protocol sign (Network LayerProtocol Identifier), version number (Version) in transmitting in the header at every turn, so the transmission of this field can be omitted fully.Simultaneously, because the header replacement has taken place, verification originally can not effectively be protected transmission of preamble, and the integrity protection of header is finished by upper-layer protocol, and the transmission of check item (Checksum) can be omitted.In addition, because ICAO (International Civil Aviation Organization, International Civil Aviation Organization) stipulated that address size is fixed as 20 bytes among the ATN, CLNP header address part length is fixed as 42 bytes thus, and therefore fixing CLNP header address is that source address and the destination address in the header also should be as the header-compressed item.
In the CLNP header, part charge length is 6 bytes, for further header compression length, after the data of the SNDCF of air-ground dialogue transmitting terminal after receiving segmentation, grouping after the segmentation is changed into a complete packet, and like this, the data after the segmentation can be cancelled part charge, thereby can save 6 bytes that need transmission, and save the transmission of section length (Segment Length).
Therefore, the corresponding relation of local header-compressed reference list number and header-compressed item is as shown in table 1 below, comprises local header-compressed reference list number, and the header-compressed item corresponding with it is protocol version, source address, destination address, secure option parameter value.And other header parameter, such as LengthIndicator (Length Indication), Lifetime (vital values), SP, MS, E/R does not change between the Type different grouping data of field in transmission course such as (types), therefore can be recovered automatically by decompression machine.
Table 1:
| Local header-compressed reference list number | Protocol version | Source address | Destination address | The secure option parameter value |
Also can not comprise protocol version in the above-mentioned header-compressed item.
Header content after the compression as shown in Figure 3, wherein P is a priority bit, when former CLNP supports priority option, this position 1; Q is QoS (service quality) option indicating bit, and when former CLNP supported the QoS option, this position was 1; R is former PDU check and indicating bit; 5 of backs correspondingly put 1 and 0 according to back 5 of QoS option parameter; Local header-compressed reference list number is the catalog number (Cat.No.) value of local header-compressed reference; PDU priority is low 4 of former CLNP packet options part priority parameters value.Above-mentioned parameters is removed local header-compressed reference list extra, and remaining is the QoS parameter that former message carries when not compressing, and this parameter is arranged in Options (option) field of original header.
In aeronautical telecommunication network, mobile subnetwork adopts and x.25 similar Subnetwork protocol structure, and the agreement of packet layer is ISO/IEC8208, and the foundation of mobile subnetwork is realized by the relevant aggregation feature layer of subnet SNDCF with maintenance.Header compression function in the air-ground dialogue is finished by SNDCF.
Set up in the process in connection, caller SNDCF and called SNDCF consult subnet connection type, compression method and local header-compressed reference list parameter.As shown in Figure 4, wherein first byte is a protocol-identifier, be defaulted as 11000001, be illustrated as mobile SNDCF, second byte is SNDCF parameter region length, and the 3rd, 4 bytes are subnetwork type, and the 7th, 8 bytes are maximum compression reference record number, the 6th byte is the compression algorithm options, and its value is as shown in the table:
Table 2
| |
0 | Deflate | M/I | S | S | LREF | CAN |
Wherein S is default spare bit, and Deflate is the pattern of traffic compression algorithm, M/I for the compression directory maintenance with set up to select the position, LREF be this locality with reference to compression options, i.e. CLNP header-compressed, CAN is local header-compressed directory delete option.
Caller SNDCF sends negotiation packets to called SNDCF, after called SNDCF receives this negotiation packets, sends one to caller SNDCF and confirms grouping, and calling and called SNDCF will use compression algorithm packed data and the transmission of consulting then.
In one embodiment of this invention, the regulation of following ISO 8208 agreements of this connection call establishment, carry parameter and the parameter meaning is seen this agreement, negotiation packets is used for the initial period that transmit leg and recipient connect, and connects to set up the follow-up transmission in back and carry out according to the parameter that consults.
Header compression method of the present invention comprises following steps as shown in Figure 5:
Step 203 is reassembled as complete packet with the grouping of segmentation;
The transmit leg and the recipient of grouping safeguard a local header-compressed reference respectively, and storage has the corresponding relation of local header-compressed reference list number and header-compressed item.When initial, its corresponding relation is empty.
Step 208 after recipient SNDCF receives grouping, judges whether grouping is compressed, if do not have, and execution in step 209, otherwise, execution in step 210;
209, recipient SNDCF extracts the header-compressed item in the local header-compressed reference list of the option part of this CLNP grouping number and this CLNP grouping, upgrade recipient's local header-compressed reference, header-compressed item in this CLNP grouping that is about to extract and local header-compressed reference list number are added into local header-compressed reference, remove the local header-compressed reference list number of the option part of CLNP grouping, give down one deck with grouping and handle, flow process finishes;
210, recipient SNDCF is according to the local header-compressed reference list of carrying in the grouping number, in recipient's local header-compressed reference, search, with substituting local header-compressed reference list number in the grouping with number corresponding header-compressed item of this this locality header-compressed reference list, recover header, give down one deck with the grouping after recovering and handle, flow process finishes.
When wherein recovering header, header is reverted to the form of transmit leg original header, but former segmentation grouped data reverts to grouping, no longer a segmentation.
In another embodiment of the present invention, can use W-LSB (Window-based LeastSignificant Bits is based on the least significant bit of window) algorithm further to compress local header-compressed reference list number, improve compression efficiency.After the header compression method of the present invention of sampling compressed header, the header after the compression was made up of local header-compressed reference list number and Header option.Wherein Header option is parameters such as above-mentioned P/Q/R/PDU priority, byte of Header option, local header-compressed reference list number 1 to 2 byte.In order further to improve compression ratio, can further use the local header-compressed reference list number in the W-LSB compression algorithm header.
Because number each other variation of the local header-compressed reference list in the header is also little, the W-LSB algorithm just in time is fit to the little field of compression variation.In the W-LSB compression mechanism, compressor reducer need be safeguarded a variable sliding window VSW (Variable Sliding Window), comprise one group with reference to base value, as long as and decompression machine receives among the VSW any one with reference to base value, correct data after the decompress(ion) compression just.When having only reference base values all among the VSW of compressor reducer all to lose, just can lose context relation between decompression machine and the compressor reducer, so the W-LSB compression algorithm has good robustness.
Local header-compressed reference list number has certain variation characteristic, and the data that generally are subordinated to same transport stream have identical local header-compressed reference list number, and the local header-compressed reference list of continuous different transport stream number also is to increase progressively with 1.For changing less field owing to remain unchanged during high-order bit transfer, variation only be several bits of low level, such as the K position, therefore only need transmit the K position bit of low level during coding transmission, can significantly increase compression ratio like this, reduce the data that need transmission.The W-LSB algorithm has utilized this characteristic, only needs the few significance bit bit of transmission, just can finish the transmission of valid data, and have good robustness.
As shown in Figure 6, the present invention makes the W-LSB algorithm number compress local header-compressed reference list mainly to comprise following steps:
Step 301 when initial, is set up with reference to base value;
When initial, the transmit leg compressor reducer empties the VSW that oneself is safeguarded, complete grouping that transmit leg sends some (as N) (comprise in the header of each grouping Header option and complete local header-compressed reference list number) is to the recipient, during grouping of every transmission, compressor reducer number is kept at the complete local header-compressed reference list in this packet header among the VSW with reference to base value as one, after the recipient receives this grouping, local header-compressed reference list complete in the header of this grouping number is kept at this locality as one with reference to base value, respectively safeguard N with reference to base value transmit leg and recipient, i.e. N local header-compressed reference list number.
The transmit leg compressor reducer obtains from recipient's decompression machine by certain feedback mechanism and somely whether is continued the information used with reference to base value, determines that when compressor reducer one no longer is extracted device when using with reference to base value, and compressor reducer should be deleted from VSW with reference to base value.
The transmit leg compressor reducer uses N the value of calculating variable K with reference to base value that comprises among the VSW: with reference to base value v_ref, the value of k_ref determined by following formula for each, with guarantee the value that will compress belong to interval section F (v_ref, k_ref):
F(v_ref，k_ref)＝[v_ref-P，v_ref+(2
k_ref-1)-P]
F (v_ref, k_ref) be an interval section, suppose that local header-compressed reference list to be compressed number is v_act, then can draw a k_ref according to reference base value v_ref and value v_act to be compressed, with guarantee value v_act to be compressed interval section F (v_ref, unique in k_ref).For among the VSW each with reference to base value, all draw the k_ref of a correspondence, therefrom choosing maximum k_ref then, is exactly the number of bits K of the needs transmission that draws of W-LSB algorithm, promptly transmits the K position bit of the low level of local header-compressed reference list to be compressed number.
P is an integer in the above-mentioned formula, its objective is in order to make the interval section can be with the v_ref move left and right, the P value does not have specific span, can get any value in theory, in order to reach maximum compression effectiveness, can take different value strategies according to the situation of change of field to be compressed, the more excellent value of P value of the present invention is as follows, wherein changes field and refers to local header-compressed reference list number in the present invention:
1) if changing field continues to increase, desirable P=-1, this moment, excursion was [v_ref+1, v_ref+2
K_ref];
2) if the variation field remains unchanged or increases, desirable P=0, this moment, excursion was [v_ref, v_ref+2
K_ref-1];
3) if change near field fluctuation up and down certain normal value, the absolute value of difference that promptly changes field and certain fixed value in the assign thresholds scope, desirable p=2
K_ref-1-1, corresponding excursion is [v_ref-2
K_ref-1+ 1, v_ref+2
K_ref-1].
Use the local header-compressed reference list of W-LSB compression algorithm number below by application example explanation.Such as local header-compressed reference list to be compressed number is 10000101 (binary representations), the reference base value of compression side and decompressor is 10000100 and 10000011, calculate k_ref according to first with reference to base value so, because local header-compressed reference list number continues to increase, get p=-1, during k_ref=1, interval is [10000101,10000110], can guarantee that 10000101 is unique in this interval, therefore the k_ref that draws is 1, promptly only needs a bit of transmission lowest order, is 2 according to second k_ref that draws with reference to base value, need two bits of transmission lowest order, so final k is 2, needs two bits of lowest order of transmission field 10000101 to be transmitted, promptly 01.
In the foregoing description, the segmentation of cancellation grouping adopts local header-compressed with reference to compressing, and further compresses by the W-LSB algorithm again.Also can not cancel segmentation, adopt local header-compressed, use the W-LSB algorithm to compress then with reference to compressing.
In further embodiment of this invention, can be by the further header compression in NHD position be set.When grouping is under the jurisdiction of two internodal Continuous Flow, protocol version in the packet header, the address, the secure option parameter remains unchanged, header content after compression this moment also remains unchanged, at this moment, after the recipient receives a complete compression behind the header, follow-up grouping is provided with NHD (No PacketHeader) position of a byte, represent the complete header that the header of follow-up grouping has sent with reference to transmit leg, like this, can be compressed finally to header and have only a byte, therefore, the method for NHD position is set, the header that carries the grouping of header after the complete compression that needs the recipient to preserve to receive at last, so that recover grouping according to being provided with of NHD, after the recipient receives this grouping, if should have no packet header position in the grouping, header recovery packet header after the complete compression that the recipient preserves according to this locality.Whenever receive a new header that carries complete header compression grouping, the originally header of the Bao Cuning header replacement that will newly be received.
For of the influence of Authentication Header compression back, use network simulator NS2 that header compression algorithm has been carried out emulation to air-ground dialogue efficient.Taked VHF Mode2 air-ground dialogue link in the emulation, bandwidth 31.5kbps, the data communication between airborne vehicle and the control tower is CPDLC communication, from 100 to 500 variations of message byte number do not wait, hover in the air simultaneously and airborne vehicle number that control tower communicates also from 10 to 50 changes and do not wait.
Fig. 7, Fig. 8, Fig. 9, Figure 10, Figure 11 are respectively the simulation result of message length when being 100,200,300,400,500 bytes, and wherein each picture in picture (a) is the message transmissions success rate, and figure (b) is the message mean transit delay.From above-mentioned figure, finally obtain when message length and airborne vehicle number change the transmission success rate of message and the simulation result of propagation delay time.
From the result, air-ground dialogue message after header-compressed success transfer rate is greatly improved before than compression, especially when message length hour.This is that introduce the transmission time that header compression algorithm can shorten message relatively this moment because in the less message of length, the transport overhead that header takies is relatively large, thereby reduces message because queuing is dropped and because the ratio that collision is dropped.
From the propagation delay time of emulation legend, the propagation delay time after the compression also is significantly less than the propagation delay time before the compression, and this also is because the compression of header has reduced total message length, thereby has reduced the transmission time.
The compression algorithm of using in the present invention and the existing air-space communication of aviation telecommunication network subnet is compared, and has cancelled the part charge of grouping, thereby has cancelled the segmentation option of compression back packet header; At the air-ground dialogue two ends default Lifetime is set, has cancelled this field in the header, saved the transmission of this two parts field; Having introduced the W-LSB algorithm number further compresses local header-compressed reference list; By being set, the NHD position unconverted header is carried out the replacement of a byte.After using this method, the CLNP header can be compressed into 1～3 byte, and with respect to 6～11 bytes of original standard, compression ratio has improved a lot.
Claims (10)
1, the header compression method in a kind of air-space communication of aviation telecommunication network, be applied to the compression of connectionless network protocol packet header, respectively safeguard a local header-compressed reference at transmit leg and recipient, wherein local header-compressed is with reference to comprising some, every comprises local header-compressed reference list number and corresponding header-compressed item, the header-compressed item is one or more parameters of packet header, when transmit leg sends to the recipient with grouped data, comprises following steps:
Transmit leg is searched local header-compressed reference according to the header-compressed item of grouped data header, after finding the local header-compressed reference list corresponding number with this header-compressed item, use this this locality header-compressed reference list compressed packet datagram header, use based on the least significant bit W-LSB compression algorithm of window should this locality header-compressed reference list number after, grouped data is sent to the recipient;
After the recipient receives grouped data, recover local header-compressed reference list number according to the W-LSB algorithm, number inquire about local header-compressed reference according to this this locality header-compressed reference list, obtain and this this locality header-compressed reference list number corresponding header-compressed item, recover the grouped data header.
2, the method for claim 1 is characterized in that, described transmit leg uses W-LSB compression algorithm and the local header-compressed reference list of decompress(ion) number to comprise following steps:
(a) respectively safeguard N with reference to base value transmit leg and recipient, promptly each is with reference to the i.e. local header-compressed reference list number of base value;
(b) transmit leg uses the W-LSB algorithm that local header-compressed reference list number is compressed, and a low level K bit of a transmitting locally header-compressed reference list number is specific as follows:
Transmit leg uses described N to come the calculating K value with reference to base value, and each with reference to base value v_ref, is determined the value of k_ref by following formula:
F(vre_f，k_ref)＝[v_ref-P，v_ref+(2
k_ref-1)-P]
F (v_ref, k_reg) be an interval section, number draw a k_ref according to reference base value v_ref and local header-compressed reference list to be compressed, guarantee local header-compressed reference list to be compressed number interval section F (v_ref, unique in k_ref), for each with reference to base value, all draw the k_ref of a correspondence, therefrom choose maximum k_ref then, i.e. the number of bits K of the needs transmission that draws of W-LSB algorithm, described P is an integer.
(c) recipient uses with reference to base value the K position bit that receives is carried out decompress(ion), recovers former local header-compressed reference list number.
3, method as claimed in claim 2 is characterized in that,
If described local header-compressed reference list number continues to increase, get P=-1;
If local header-compressed reference list number remains unchanged or increases, get P=0;
If the absolute value of local header-compressed reference list number and certain difference that often is worth is got p=2 in assign thresholds
K_ref-1-1.
4, method as claimed in claim 2, it is characterized in that, described transmit leg sends N grouped data to the recipient, wherein comprise complete local header-compressed reference list number in the header of each grouped data, during grouped data of every transmission, wherein local header-compressed reference list number is kept in the variable sliding window of transmit leg with reference to base value as one, after the recipient receives this grouped data, wherein local header-compressed reference list number is kept at this locality as one with reference to base value, thereby obtains N with reference to base value.
5, method as claimed in claim 2, it is characterized in that, described transmit leg obtains the some information that whether is continued use with reference to base value by feedback mechanism from the recipient, determine one with reference to base value when no longer the side of being received uses when transmit leg, transmit leg should be deleted from the variable sliding window of transmit leg with reference to base value.
6, the method for claim 1 is characterized in that, after transmit leg was merged into a grouping with the grouped data of segmentation, the segmentation option part in the cancellation header was compressed header again.
As the arbitrary described method of claim 1 to 6, it is characterized in that 7, described header-compressed item comprises protocol version, source address, destination address and secure option parameter value.
As the arbitrary described method of claim 1 to 6, it is characterized in that 8, transmit leg and recipient's local header-compressed is with reference to setting up in the following way:
Transmit leg is searched local header-compressed reference according to the header-compressed item of grouped data header, if when not finding corresponding local header-compressed reference list, transmit leg local header-compressed with reference in increase a new local header-compressed reference list number, this new local header-compressed reference list number is corresponding to the header-compressed item of this packet header;
Transmit leg should new local header-compressed reference list number inserts in this grouping, keeps the header of grouped data, and grouped data is sent;
After the recipient receives this grouping, extract the local header-compressed reference list of carrying in this grouping number and header-compressed item, this header-compressed item and local header-compressed reference list number are added into recipient's local header-compressed reference.
9, method as claimed in claim 8 is characterized in that, transmit leg sends after will this new local header-compressed reference list number inserting option part in this grouping.
10, as claim 1 or 2 or 6 described methods, it is characterized in that, the recipient preserves the header of the grouping of carrying complete header compression of receiving at last, during transmit leg transmission grouping, when the header of grouping was the same with the header of the grouping of having transmitted, transmit leg was provided with no packet header position, after the recipient receives this grouping, if should have no packet header position in the grouping, the complete header compression that the recipient preserves according to this locality recovers packet header.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA200810101523XA CN101237419A (en) | 2008-03-07 | 2008-03-07 | Packet header compression method in air-space communication of aviation telecommunication network |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNA200810101523XA CN101237419A (en) | 2008-03-07 | 2008-03-07 | Packet header compression method in air-space communication of aviation telecommunication network |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN101237419A true CN101237419A (en) | 2008-08-06 |
Family
ID=39920784
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNA200810101523XA Pending CN101237419A (en) | 2008-03-07 | 2008-03-07 | Packet header compression method in air-space communication of aviation telecommunication network |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN101237419A (en) |
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102006295A (en) * | 2010-11-26 | 2011-04-06 | 重庆金美通信有限责任公司 | Data compression method based on asynchronous transfer mode (ATM) carried IP voice |
| WO2011079785A1 (en) * | 2009-12-31 | 2011-07-07 | 华为技术有限公司 | Method and apparatus for transmitting data packets |
| CN102571572A (en) * | 2011-12-28 | 2012-07-11 | 中国人民解放军国防科学技术大学 | Short message satellite communication-based data transmission method and device |
| CN103179094A (en) * | 2011-12-22 | 2013-06-26 | 中兴通讯股份有限公司 | Sending method, receiving method, sending device and receiving device of Internet Protocol (IP) message headers |
| CN102118293B (en) * | 2009-12-30 | 2015-04-29 | 上海可鲁系统软件有限公司 | Method for compressing and storing communication messages |
| CN105207984A (en) * | 2014-06-19 | 2015-12-30 | 凯为公司 | Method Of Representing A Generic Format Header Using Continuous Bytes And An Apparatus Thereof |
| CN105659612A (en) * | 2014-03-11 | 2016-06-08 | Lg电子株式会社 | Method and device for transmitting/receiving broadcast signal |
| CN106297421A (en) * | 2015-06-24 | 2017-01-04 | 霍尼韦尔国际公司 | Improve aerocraft system and the method for airport traffic management |
| CN103731424B (en) * | 2013-12-30 | 2017-09-15 | 优视科技有限公司 | A kind of transmission method of network data, apparatus and system |
| CN109167791A (en) * | 2018-09-18 | 2019-01-08 | 中电科航空电子有限公司 | A method of airborne ATN protocol stack network layer is motivated and is verified |
| US10785169B2 (en) | 2013-12-30 | 2020-09-22 | Marvell Asia Pte, Ltd. | Protocol independent programmable switch (PIPS) for software defined data center networks |
| US11050859B2 (en) | 2014-06-19 | 2021-06-29 | Marvell Asia Pte, Ltd. | Method of using bit vectors to allow expansion and collapse of header layers within packets for enabling flexible modifications and an apparatus thereof |
| DE102020118371A1 (en) | 2020-07-13 | 2022-01-13 | Heraeus Deutschland GmbH & Co. KG | Multi-layer ring electrode with multiple openings |
| US11258886B2 (en) | 2014-06-19 | 2022-02-22 | Marvell Asia Pte, Ltd. | Method of handling large protocol layers for configurable extraction of layer information and an apparatus thereof |
-
2008
- 2008-03-07 CN CNA200810101523XA patent/CN101237419A/en active Pending
Cited By (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102118293B (en) * | 2009-12-30 | 2015-04-29 | 上海可鲁系统软件有限公司 | Method for compressing and storing communication messages |
| WO2011079785A1 (en) * | 2009-12-31 | 2011-07-07 | 华为技术有限公司 | Method and apparatus for transmitting data packets |
| CN102118792B (en) * | 2009-12-31 | 2015-01-21 | 华为技术有限公司 | Method and device for transmitting data packets |
| CN102006295A (en) * | 2010-11-26 | 2011-04-06 | 重庆金美通信有限责任公司 | Data compression method based on asynchronous transfer mode (ATM) carried IP voice |
| CN103179094A (en) * | 2011-12-22 | 2013-06-26 | 中兴通讯股份有限公司 | Sending method, receiving method, sending device and receiving device of Internet Protocol (IP) message headers |
| CN102571572A (en) * | 2011-12-28 | 2012-07-11 | 中国人民解放军国防科学技术大学 | Short message satellite communication-based data transmission method and device |
| US10785169B2 (en) | 2013-12-30 | 2020-09-22 | Marvell Asia Pte, Ltd. | Protocol independent programmable switch (PIPS) for software defined data center networks |
| US11824796B2 (en) | 2013-12-30 | 2023-11-21 | Marvell Asia Pte, Ltd. | Protocol independent programmable switch (PIPS) for software defined data center networks |
| CN103731424B (en) * | 2013-12-30 | 2017-09-15 | 优视科技有限公司 | A kind of transmission method of network data, apparatus and system |
| US10122803B2 (en) | 2013-12-30 | 2018-11-06 | Uc Mobile Co., Ltd. | Network data transmission method, device and system |
| US10674233B2 (en) | 2014-03-11 | 2020-06-02 | Lg Electronics Inc. | Method and device for transmitting/receiving broadcast signal |
| US10009665B2 (en) | 2014-03-11 | 2018-06-26 | Lg Electronics Inc. | Method and device for transmitting/receiving broadcast signal |
| CN105659612B (en) * | 2014-03-11 | 2018-12-28 | Lg 电子株式会社 | Transmission/reception broadcast singal method and apparatus |
| CN105659612A (en) * | 2014-03-11 | 2016-06-08 | Lg电子株式会社 | Method and device for transmitting/receiving broadcast signal |
| CN105207984A (en) * | 2014-06-19 | 2015-12-30 | 凯为公司 | Method Of Representing A Generic Format Header Using Continuous Bytes And An Apparatus Thereof |
| US11050859B2 (en) | 2014-06-19 | 2021-06-29 | Marvell Asia Pte, Ltd. | Method of using bit vectors to allow expansion and collapse of header layers within packets for enabling flexible modifications and an apparatus thereof |
| US11258886B2 (en) | 2014-06-19 | 2022-02-22 | Marvell Asia Pte, Ltd. | Method of handling large protocol layers for configurable extraction of layer information and an apparatus thereof |
| US11799989B2 (en) | 2014-06-19 | 2023-10-24 | Marvell Asia Pte, Ltd. | Method of using bit vectors to allow expansion and collapse of header layers within packets for enabling flexible modifications and an apparatus thereof |
| CN106297421A (en) * | 2015-06-24 | 2017-01-04 | 霍尼韦尔国际公司 | Improve aerocraft system and the method for airport traffic management |
| CN109167791A (en) * | 2018-09-18 | 2019-01-08 | 中电科航空电子有限公司 | A method of airborne ATN protocol stack network layer is motivated and is verified |
| CN109167791B (en) * | 2018-09-18 | 2021-05-18 | 中电科航空电子有限公司 | Method for excitation verification of network layer of airborne ATN protocol stack |
| DE102020118371A1 (en) | 2020-07-13 | 2022-01-13 | Heraeus Deutschland GmbH & Co. KG | Multi-layer ring electrode with multiple openings |
| US11617883B2 (en) | 2020-07-13 | 2023-04-04 | Heraeus Deutschland GmbH & Co. KG | Multilayer ring electrode having a plurality of openings |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101237419A (en) | Packet header compression method in air-space communication of aviation telecommunication network | |
| EP2854359B1 (en) | Compression and decompression methods of ethernet header and corresponding devices | |
| CN1307831C (en) | Context identification using header compression key at link layer | |
| CN101568144B (en) | Header compression method applicable to wireless ad hoc network | |
| RU2424627C2 (en) | Dynamic robust header compression | |
| EP2479952B1 (en) | Method for compressing and decompressing time stamp and equipment thereof | |
| JP3751823B2 (en) | Header compression in real-time services | |
| CN102882879B (en) | A kind of IP data compression transmission method being applicable to satellite channel | |
| CN100454920C (en) | Extension header compression | |
| US20060104278A1 (en) | Apparatus and method for compressing headers in a broadband wireless communication system | |
| CN1097933C (en) | Method and device for transforming a series of data packets by means of data compression | |
| EP1362446A1 (en) | Transfer of ip data in communications system, using several logical connections for compressed fields on the basis of different contexts | |
| EP2098035A2 (en) | Improved header compression in a wireless communication network | |
| US8817821B2 (en) | Method and device for user datagram protocol packet compression and decompression | |
| CN103369593B (en) | A kind of method compressing reconciliation compressed ethernet message and network element device | |
| CN104917591A (en) | Satellite network data package compression method suitable for uni-directional lossy link | |
| CN102420672A (en) | Method for wireless local area network wireless access point to carry out data forwarding to wireless controller | |
| EP2127298A1 (en) | Header supression in a wireless communication network | |
| CN101162973A (en) | Method and devices for digital data transfer | |
| US20080144555A1 (en) | Apparatus and method for identifying header compression channel in broadband wireless communication system | |
| CN104283916A (en) | Data message transmission method and device applied to HFC network | |
| CN106982165A (en) | Data compression method and its system | |
| US9456380B2 (en) | Data compression in a communications network | |
| CN101453465A (en) | IP packet compression, decompression method for mobile multimedia broadcast system | |
| CN1647468B (en) | Method and system for compressing and transmitting multimedia data |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C12 | Rejection of a patent application after its publication | ||
| RJ01 | Rejection of invention patent application after publication |
Open date: 20080806 |