CN100411327C

CN100411327C - Appts. and method for delivery of packets in multi-hop wireless networks

Info

Publication number: CN100411327C
Application number: CNB028108736A
Authority: CN
Inventors: 戈文达拉简·科立什纳莫蒂; 伊勒·郭
Original assignee: Nokia Oyj
Current assignee: Nokia Oyj; Nokia Inc
Priority date: 2001-06-30
Filing date: 2002-06-26
Publication date: 2008-08-13
Anticipated expiration: 2022-06-26
Also published as: EP1415424A1; EP1415424A4; WO2003005629A1; MXPA03010849A; JP2007251991A; AU2002311547B2; RU2298289C2; JP4392033B2; CA2449532A1; JP2004537206A; RU2003134626A; CN1541466A

Abstract

A system and method are disclosed for reducing data loss in wireless networks resulting from corruption of one or more wireless links or resulting from failure of an intermediate connecting node. The wireless network, which includes at least one intermediate node (15) having an internal buffer (71) for continually buffering data passing from source node (11) to destination node (21), establishes an alternate path bypassing the failed node. Lost data packets are locally retransmitted in response to receipt of an error message indicating node failure, or in response to a retransmit request resulting from data corruption over a wireless link. Intermediate nodes lacking such internal buffering serve to relay requests and messages upstream to nodes with internal buffering.

Description

Be used for transmitting the equipment and the method for grouping at multi-hop wireless network

Technical field

The present invention relates to wireless communication system, relate in particular to a kind of system and method that when link or node failure having occurred, reduces the transfer of data loss.

Background technology

On characteristic, the wireless multi-hop mobile network lacks clear and definite framework, will be subjected to the frequent link failure that interference caused in node motion and the Radio Link thus.This has just proposed a problem aspect the service quality in guaranteeing this network (QoS).As understanding, retransmit the time limit that can not satisfy timely transmission grouping usually end to end in association area.Especially, the multimedia transmission is the application example that is subjected to the packet loss adverse effect.For instance, can in following application, find multi-hop wireless network, comprising the application, Military Application, taxi network, the meeting room network that are used for individual zone networking, and emergency uses, be included between the group that relates to search and rescue task or the doctor via the ambulance operator of the scene of the accident and remote hospital between the network set up " 911 calling " coordinated.

Therefore, wireless mobile multi-hop network of network topological structure changed along with the time, and wherein network node moves, and will set up link, then stops described link then.Compare with cable network,, therefore transient fault takes place more likely in this radio link because radio link is more responsive to disturbing.Thereby in this network, Route Selection is a very difficult problem and can't guarantees a path from the source to the destination for whole communication session.

Taked at present the several studies plan to optimize Routing Protocol in the multihop network.Disturbing the node motion or the link degradation that cause to cause under the situation of link failure owing to transmission, these Routing Protocols will be optimized the route of source node to destination node.Many standards have been proposed at present, so that use this optimizing process to set up communication path.The some of them standard is included as mobile system and reduces the congested reserve capacity of coming.Equally, advised rewriting TCP/UDP at present, so that in a multihop network, transmit grouping.

In this area, existing project at be the Route Selection problem, but and the partial retransmission and the priorization that reckon without grouping send.The agreement that association area is discussed relies on such as this higher layer of TCP and handles packet loss.This method depends on the end-to-end re-transmission of lost packets, is unsuitable for guaranteeing the QoS in the wireless multi-hop network equally, link failure wherein often takes place, and this can cause excessive delay.In addition, because the grouping from the source and course to the destination is handled in the same manner, therefore this method is not taken the priorization in the packet delivery into account.Different miniflows in a stream may have difference send time limit in, this method is not the best approach.And the association area that preferentially is delivered in the cable network is known, but in wireless network, can't guarantee punctual transmission owing to very high transmission error probability.

Need at present a kind of improved method, be used for providing packet delivery timely at the mobile multi-hop network having under the situation of high quality-of-service very.

Summary of the invention

The present invention comes from a kind of like this observation, and that is exactly to use hierarchical network that packet is cached to the intermediate node of transmission path, and those lost data packets of partial retransmission, relaxes the loss of data in the wireless network thus.Wireless network is to use one or more intermediate nodes to form, these nodes have internal buffer, be used for continuously buffer memory those are delivered to the data of destination node from source node, described wireless network is set up a replacement path of walking around malfunctioning node, and retransmits those lost data packets in response to the reception of error message.If connected node does not have internal buffer, error message will upwards be sent to a node so, the data that described node divides into groups buffer memory in addition and can provide those to lose data.

Description of drawings

Hereinafter, description of the invention has been quoted accompanying drawing, wherein:

Fig. 1 is a diagram that shows the wireless network of the formed communication path of connected node;

Fig. 2 is a flow chart that the transfer of data that wireless network carried out of using Fig. 1 is described;

Fig. 3 is one and has shown and be used for the sketch of buffer memory via Fig. 1 connected node of the internal buffer of the data of node;

Fig. 4 is one and has shown and be used for the sketch of buffer memory via Fig. 1 connected node of the height of node, normal, low priority transmission buffer device;

Fig. 5 is the not flow chart of the processing of Data transmission grouping of a transmission shown in more detailed description Fig. 2 flow chart;

Fig. 6 is a diagram that has comprised the wireless network of the connected node that does not have inner buffer;

Fig. 7 is the diagram that has comprised the wireless network of a Radio Link that breaks down; And

Fig. 8 is a flow chart that the transfer of data that wireless network carried out of using Fig. 7 is described.

Embodiment

Fig. 1 has shown a simple wireless network 10, comprising source node 11 (S) and destination node 21 (D).The user of wireless network 10 can set up an initial communication path via connected node in the middle of a succession of between source node 11 and destination node 21, send data thus.For purpose of explanation, initial communication path can comprise: from source node 11 to first connected nodes or intermediate node 13 (N ₀₁) route segment, to second intermediate node, 15 (N ₀₂) route segment, to the 3rd intermediate node 17 (N ₀₃) route segment, to the 4th intermediate node 19 (N ₀₄) route segment, be route segment then to destination node 21.Initial communication path can be set up by the serial combination of following link: the Radio Link 31 between the source node 11 and first intermediate node 13, Radio Link 33 between first intermediate node 13 and second intermediate node 15, Radio Link 35 between second intermediate node 15 and the 3rd intermediate node 17, Radio Link 37 between the 3rd intermediate node 17 and the 4th intermediate node 19, and the Radio Link 39 between the 4th intermediate node 19 and the destination node 21.

Carrying out via initial communication path in the process of transfer of data, one or more intermediate node 13-19 might break down.For instance, fault might be because stop connected node (for example equipment fault or outage) caused by operations, might also might be because the unfavorable communication environments (for example Atmospheric precipitation or turbulent flow) of influenced intermediate node causes also because mobile node shifts out relevant Radio Link scope to be caused.Therefore, the fault of middle connected node will cause one or more Radio Link 31-39 to lose, and causes initial communication path to interrupt thus, produces loss of data or mistake then.In association area, the detection of node failure is well-known, and for instance, described detection can be used a kind of timeout mechanism.

The operation of the inventive method can also be described with reference to the flow chart of figure 2, wherein in step 51, initial communication path is set up with a kind of association area known method, and has disposed a data stream of packets 29, so that send according to appropriate agreement.Initiate via initial communication path because data packet flows 29 is sent to destination node 21, therefore in data packet flows 29, each respective data packet is passed through each intermediate node 13-19 successively.As hereinafter in greater detail, at least one intermediate node in the initial communication path is configured, so that use priority query to come possible partial retransmission is carried out buffer memory in step 57.If initial communication path is intact and detect a node failure at decision block 59, so in step 61, system will wait pending transmission next time, and in step 53, system will receive these packets when packet is provided.

If intermediate node breaks down, thereby cause the one or more Radio Link 31-39 that form initial communication path to interrupt, will use the known method of a kind of association area to set up the access path of a replacement in step 63 so, in step 65, remaining not Data transmission grouping is sent to destination node 21, so that the transmission of end data stream of packets 29.For instance, shown in Fig. 1 dotted line, if the 3rd intermediate node 17 breaks down,

Radio Link

35 and 37 will be lost so, and initial communication path will be interrupted thus.Second intermediate node 15 will be apprised of described fault and will find that one is walked around the 3rd intermediate node 17 that breaks down and arrives the replacement communication path of destination node 21.For instance, the communication path of this replacement can comprise that one first is replaced connected node 23 (N ₁₁) and the second replacement connected node, 25 (N ₁₂).

Between second intermediate node 15 and the first replacement connected node 23, can form a new Radio Link 41, between the first replacement connected node 23 and the second replacement connected node 25, another new Radio Link 43 can be formed, and between the second replacement connected node 25 and the 4th intermediate node 19, a new Radio Link 45 can be formed.Then, as hereinafter in greater detail, the grouping of remaining not Data transmission will send to destination node 21 in step 67.If the decision block 61 at Fig. 2 does not finish transmission session, so described operation will return to step 53, and next part that wherein will configuration data stream of packets 29 is for transmission.

In a preferred embodiment, each self-contained at least one internal buffer of one or more intermediate node 13-19 is so that continuously those packets through corresponding connected node of buffer memory.As second intermediate node 15 of more detailed demonstration among Fig. 3 is illustrated, wherein comprise an internal buffer 71 that is used to preserve a plurality of packets.The size of buffer 71 depends on the shelf storage quantity that can be used for this function in second intermediate node 15, and described buffer determines by one or more factors, comprising bandwidth and the rate travel used.If there are enough memories to use, then can increase the size of buffer 71, so that handle those, and hold those and finding to replace the packet that arrives in the process in path via corresponding connected node and the relative higher data transmission of speed.

Buffer 71 can be used as " software " buffer that has comprised a part of memory that resides on second intermediate node 15 and carries out, and a hardware component that also can be used as in second intermediate node 15 provides, for example RAM.Software cache can carry out buffer memory and obtains implementing by reconfiguring joint core.That is to say that the central role that reconfigures is distinguished in buffer and to the order of priority of grouping, in addition repeat requests is made response.As known in the art, this request will obtain resolving, and one or more groupings will be arranged in one or more buffers, and described one or more groupings will be dispatched in the outside formation.As selection, second intermediate node 15 can comprise a selectable process unit 79, so that sign, preservation and the re-transmission of packet in the control buffer 71.For instance, send

packet

29a, 29b ..., 29n arrives on the Radio Link 33 and when outwards being routed to Radio Link 35, buffer 71 also respectively packet 29a, the 29b of the nearest transmission of

cache memory location

71a, 71c and 71e ..., 29n.Buffer 71 can be followed a first-in first-out agreement.As selection, buffer memory can carry out based on each stream, and wherein the packet of specific stream has replaced with data in buffer grouping in advance in first-class.

In a preferred embodiment, each self-contained three internal buffer of intermediate node 13-19, as the buffer 73-77 that indicates in the diagram of the 4th intermediate node 19 of Fig. 4 is illustrated, buffer comprises a part of available memory or a discrete memory chip.In this structure, for instance, by high-priority buffer 73, normal priority buffer 75 and low-priority buffer device 77 are provided, can use these three buffer 73-77 and will receive

packet

29a, 29b ..., 29n is separated into different transmission priority grades.Therefore, can arrange, before the packet that sends low-priority buffer device 77, send described packet so that use the known method of association area the packet in the high-priority buffer 73.

Fig. 5 is a flow chart in greater detail that the performed operation of Fig. 2 step 65 is provided.From step 63, for instance, use connected

node

15,23,25 and 19 and set up replacement path between the

intermediate node

15 and 19 as shown in Figure 1 in step 81.Therefore, also be buffered in the replacement connected

node

23 and 25 along the packet of replacing path flow now.The 4th intermediate node 19 is to reconfigure under the situation of having set up the replacement transmission path.That is to say, before the 3rd intermediate node 17 broke down, packet sent to port one 9a from the 3rd intermediate node 17, as an alternative at first, after the 3rd intermediate node 17 broke down, described packet was replaced connected node 25 from second and is sent to port one 9b.Various equivalent modifications can be understood, and the 4th intermediate node 19 that reconfigures is first downstream nodes in the new transmission path, and it is positioned at initial communication path and replaces on the transmission path.In step 83, when the 4th intermediate node 19 receives a path about same stream (just data packet flows 29) when setting up message, the 4th intermediate node 19 assert that fault has appearred in the 3rd intermediate node 17 and by informing to second intermediate node 15 which packet the 4th intermediate node 19 receives and make response.This operation will be carried out, so that avoid retransmitting the packet of repetition.

For instance, as described in Figure 4,

packet

29a and 29n arrived the 4th intermediate node 19 before the 3rd intermediate node 17 breaks down.When the 4th intermediate node 19 assert that the transmission path that reconfigures (that is to say, packet from second intermediate node 15 arrives port one 9b rather than 19a), a notice that has received

packet

29a and 29n will send to second intermediate node 15.Then, second intermediate node 15 is checked, so that judge which the 4th intermediate node 19 do not received and sent to the packet of the 3rd intermediate node 17 and judge that the 4th intermediate node 19 does not receive packet 29b.

In step 85, be identified as lost data packets immediate upstream node from initial communication path and obtain, wherein destination node has the corresponding data through buffer memory.Packet 29b illustration a lost data packets, the described packet of retrieval and send it to the 4th intermediate node 19 by replacing the path from the buffer 71 of second intermediate node 15 then in step 87.The 4th intermediate node 19 is sent to destination node 21 with

packet

29a, 29b and 29n.If suitable host-host protocol needs orderly delivering data grouping, packet 29n just is sent to destination node 21 after having transmitted packet 29a so.Perhaps, if suitable host-host protocol does not need to send in order, so,, then send packet 29b prior to packet 29a and the 29n that is buffered in the low-priority buffer device 77 if packet 29b is buffered in the high-priority buffer 71.In addition, in step 87, the remainder of data packet flows 29 sends via replacing the path.Then, in Fig. 2, described operation will turn back to step 61.

In an alternative embodiment of the inventive method that Fig. 6 shows, wireless network 10 comprises an intermediate node 27 that does not have buffer memory, does not wherein provide memory resource at intermediate node 27 for internal buffer.Therefore, intermediate node 27 can't those packets of transmitting along transmission path of buffer memory.Yet intermediate node 27 can upstream passing message and can be found to replace the path under the situation that node or link break down.If as mentioned above, break down such as the 3rd intermediate node 17 such intermediate nodes, intermediate node 27 will receive a resend messages 49 so.Because intermediate node 27 can not provide lost data packets in response to node failure, therefore, for instance, resend messages 49 will upwards send to the next intermediate node with internal buffer, for example first intermediate node 13.The so one or more lost data packets of packet 29b shown in illustration are obtained from any one buffer 73-77, and provide it to requesting node, and described here node is illustrative by the 4th intermediate node 19.If lost data packets 29b is not present among any one buffer 73-77 of first intermediate node 13, so described message will send to source node 11.In a kind of network configuration, do not exist intermediate node and source node 11 to comprise internal buffer between malfunctioning node and the source node 11, so as mentioned above, lost data packets obtains and sends to requesting node from source node 11.

In another alternative embodiment, for instance, the Radio Link 37 in the wireless network 10 is owing to transmission medium shown in Figure 7 is interfered the degradation or unreliable that becomes.May introduce mistake in the transmitted in packets between the 3rd intermediate node 17 and the 4th intermediate node 19 thus.Flow chart that here can additional reference Fig. 8 is described corrective action, wherein set up initial communication path, and, received those packets from data packet flows 29 at intermediate node in step 93 in step 91, and in step 95 with its buffer memory.

If Radio Link 31-39 still has effect, then do not receive resend messages, and in step 101, system will wait pending transmission at decision block 99.When Radio Link 37 becomes unreliable and produce transmission error, will receive a resend messages, and in step 103, the 3rd intermediate node 17 is searched for corresponding packet in internal buffer 73-77.At decision block 105, if found packet among a buffer 73-77 therein, so in step 97, the 3rd intermediate node 17 will be dispatched to outside formation (not shown) to the packet that is used for the priority re-transmission.As mentioned above, this transmitting and scheduling is to carry out according to the transmission priority of packet.

At decision block 105, if do not find needed packet in the internal buffer 73-77 of the 3rd intermediate node 17, so in step 107, next upstream node will be checked the replacement data of being asked.If found the data of being asked, then send described data in step 97 at decision block 109.If do not find the data of being asked at decision block 109, then make an inquiry that whether has reached source node 11 at decision block 111.If do not reach source node 11, then operation proceeds to decision block 105.If reached source node 11 and do not comprised needed packet at decision block 113 at decision block 111, so in step 115, an optional error message can be distributed to the starting station of transfer of data, and in step 101, operation will proceed to waits for next transmission session.If at decision block 113, the packet of being asked is available, then dispatch and priorization, so that send it to destination node 21 in step 97 pair data grouping.

Though invention has been described with reference to specific embodiment, should understand, the present invention is in no way limited to here the ad hoc structure and the method that show among open and/or the figure, but has comprised any modification or equivalent in the claim scope.

Claims

1. one kind is sent to the method for destination node with packet from source node in wireless network, comprising:

Set up one from source node (11) by the initial communication path of a plurality of intermediate nodes to destination node (21);

First intermediate node (27) from described a plurality of intermediate nodes sends packet (29a) to destination node (21);

Determine whether described destination node (21) receives described packet (29a);

Do not receive described packet (29a) in response to definite described destination node (21), determine whether described packet (29a) is buffered in described first intermediate node (27); And

Be not buffered in described first intermediate node (27) in response to definite described packet (29a), request is replaced communication path and is retransmitted described packet (29a) from second intermediate node (13) of first intermediate node (27) upstream by being different from first of described initial communication path.

2. the process of claim 1 wherein that described second intermediate node comprises a plurality of buffers (71), each in described a plurality of buffers (71) is corresponding to different priority levels.

3. the method for claim 2 also comprises in response to definite described packet (29a) being buffered in described first intermediate node (27), replaces communication path from first intermediate node (27) by second and retransmits described packet (29a).

4. the method for claim 1 also comprises and works as described packet (29a) in the described packet of buffer memory (29a) in out-of-date first buffer at first intermediate node on the initial communication path.

5. the method for claim 4, wherein said initial communication path comprises the 3rd intermediate node (17) in first intermediate node (27) downstream.

6. the method for claim 5 determines wherein whether described destination node (21) receives described packet (29a) and comprise the fault that detects the 3rd intermediate node (17).

7. the method for claim 3, wherein retransmitting described packet (29a) from first intermediate node (27) is to dispatch according to the priority level the output queue.

8. the method for claim 3 is wherein replaced communication path from first intermediate node (27) by second and is retransmitted described packet (29a) and be included in described first intermediate node and be in to send to be buffered in than second packet (29b) the second low buffer of the first buffer priority and retransmit described packet (29a) before.

9. the method for claim 8, wherein said second replaces communication path does not comprise the 3rd intermediate node (17).

10. the method for claim 6, the fault that wherein detects the 3rd intermediate node (17) comprises the reception resend messages.

11. the method for claim 6, wherein said first replaces communication path does not comprise the 3rd intermediate node (17).

12. the method for claim 6, wherein said initial communication path also comprise the 4th intermediate node (19) that is positioned between the 3rd intermediate node (17) and the destination node (21).

13. the method for claim 12 also is included in the notice that first intermediate node (27) locates to receive from the 4th intermediate node (19) lost packets.

14. one kind is sent to the cordless communication network of destination node with packet from source node, comprising:

Source node (11);

Destination node (21);

A plurality of intermediate nodes, wherein, set up initial communication path by at least the first intermediate node (27) in a plurality of intermediate nodes and second intermediate node (13) between source node (11) and destination node (21), described second intermediate node (13) is in the upstream of first intermediate node (27)

Wherein, determine to fail to arrive destination node (21) in response to first intermediate node by the packet (29a) that initial communication path sends, if described packet (29a) is not buffered in first intermediate node (27), then first intermediate node (27) sends repeat requests to second intermediate node (13), and

Wherein, second intermediate node (13) retransmits described packet (29a) from first buffer (73) of second intermediate node (13) along the replacement communication path that is different from described initial communication path.

15. the communication network of claim 14, wherein, dispose first intermediate node (27) to come specified data grouping (29a) whether to arrive destination node (21) by the fault that detects the 3rd intermediate node (17) in a plurality of intermediate nodes, wherein, described the 3rd intermediate node (17) is in first intermediate node (27) downstream.

16. the communication network of claim 14, wherein, the 4th intermediate node (19) that is positioned between the 3rd intermediate node (17) and the destination node (21) is notified described first intermediate node (27) lost packets.

17. the communication network of claim 15, wherein, described replacement communication path does not comprise described the 3rd intermediate node (17).

18. the communication network of claim 14, wherein, described second intermediate node (13) also comprises second buffer (75), and it has and the different priority level of first buffer (73).

19. the communication network of claim 18 wherein, is dispatched the re-transmission of described packet (29a) according to priority level.

20. one kind is sent to the method for destination node with packet from source node, comprises in wireless network:

Receive packet (29a) at the first intermediate node place from upstream node;

In the first described packet of intermediate node place buffer memory (29a);

Along an initial communication path described packet (29a) is sent to second intermediate node;

Receive repeat requests from second intermediate node, wherein said repeat requests indicates described packet (29a) not to be buffered in described second intermediate node; And

In response to described repeat requests, to replace communication path by one and retransmit described packet (29a), described replacement communication path is since first intermediate node, and is different from initial communication path.

21. the method for claim 20, wherein, described first intermediate node comprises a plurality of buffers, and each buffer is corresponding to different priority levels.

22. the method for claim 21, wherein, described packet is buffered in first buffer of selecting from described a plurality of buffers according to first priority level of this packet.

23. the method for claim 20, wherein, described upstream node is source node (11).

24. the method for claim 20, wherein, the described packet of buffer memory (29a) was carried out before receiving repeat requests.

25. the method for claim 20, wherein, described repeat requests is corresponding to the fault of the 3rd intermediate node (17) between second intermediate node and destination node.

26. the method for claim 25, wherein, described replacement communication path does not comprise the 3rd intermediate node (17).