CN1555634A - System and method for multipoint to multipoint data communication - Google Patents
System and method for multipoint to multipoint data communication Download PDFInfo
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- CN1555634A CN1555634A CNA028180879A CN02818087A CN1555634A CN 1555634 A CN1555634 A CN 1555634A CN A028180879 A CNA028180879 A CN A028180879A CN 02818087 A CN02818087 A CN 02818087A CN 1555634 A CN1555634 A CN 1555634A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/407—Bus networks with decentralised control
- H04L12/417—Bus networks with decentralised control with deterministic access, e.g. token passing
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/28—Data switching networks characterised by path configuration, e.g. LAN [Local Area Networks] or WAN [Wide Area Networks]
- H04L12/40—Bus networks
- H04L12/40006—Architecture of a communication node
- H04L12/40032—Details regarding a bus interface enhancer
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Abstract
A system and method is provide for multipoint to multipoint data communication. In an embodiment of the invention, a system comprises a communications medium interconnecting at least one central server and a plurality of communication nodes. The central server transmits information to the nodes via a Forward Channel and the nodes transmit information via a Reverse Channel. Before transmitting, each of the nodes listens (monitors) during an assigned slot of a Clear Channel Assessment interval of the communications cycle to ascertain whether any other node is transmitting. A given node transmits data only when that node determines that the network is clear. The nodes listen in sequential order, eliminating the probability of collisions caused by simultaneous transmissions from nodes. A query channel interval is provided for nodes not assigned a slot within clear channel assessment interval to request a slot. Assigned slots not used by nodes are allocated to other nodes. The data traffic is accordingly aggregated, thus providing efficient utilization.
Description
Background of invention
Invention field
The present invention relates to data communication, relate in particular to the system and method that is used for multi-multipoint communication.
Description of Related Art
In Local Area Network, one group of device interconnects by the network media of sharing.With reference to figure 1, the traditional LAN with bus topology is shown is provided with 100.LAN100 so-called " multi-multipoint " system is because any one in the multiple arrangement can send to information other device among one, some or all of system in the system.Particularly, common share communication media 110 is connected to these devices.Communication medium 110 generally includes optical fiber, coaxial cable, composite fibre coaxial (HFC) network, wireless medium or any its combination.Described device comprises central server 120, and it carries out a plurality of functions in the known mode of those skilled in the art in the present technique field, comprises the coordination of communicating by letter between number other device 130 for " N " that also is connected to common share communication media 110.In addition, in this LAN was provided with, except the lan access of management to all devices that connecting 130, central server 120 was also with the gateway of accomplishing external network.Usually, communicator 130 is also referred to as node, and they are the calculation elements such as computer or printer.Though show bus topology, those skilled in the art are understandable in the present technique field is, also can use other topology, comprises ring topology; Star topology; Combination with bus, annular and Star topology.
Be further appreciated that two main purposes are speed and reliability in network or any other design of communication system.In other words, to arrive its destination fast and reliably be very important to the information unit that places network (" grouping ") that is connected to network by any device.When attempting using network simultaneously, the two or more devices that are connected to network occurred and the afoul important phenomenon of these purposes of realization.This can cause data collision, and it stops any data to arrive its destination.As a result, all devices that are absorbed in conflict must attempt sending their data later on again, have reduced network speed and efficient thus.
There are a lot of known settings in the prior art, are used to make the possibility minimum of conflict and are used for when producing conflict, optimizing recovery.But, still needing a kind of system, it can make the possibility of conflict minimum and the fast quick-recovery of conflict is provided and does not cause about increasing a large amount of losses of system burden.
Summary of the invention
The present invention is directed to a kind of system and method that is used for effective multi-multipoint communication.The present invention is by having overcome the defective of conventional system and agreement according to traffic needs dynamic bandwidth allocation.
In one embodiment, in lan environment, provide and communicate by letter with central server and a plurality of nodes.At work, central server sends to node with the form of the packet forward channel by communication cycle with information and node sends to packet one or more other nodes and/or central server in backward channel.But before sending on the backward channel, each node is listened to (i.e. monitoring) network to determine whether any other node is using network distributed to its clear channel evaluation time time slot by central server during.Each node with outgoing data was only determined to send data after the network blank during the clear channel evaluation time.Node is listened to continuous order, has eliminated the probability of the conflict that causes by the synchronous transmission from node.
Therefore, this configuration aggregate data traffic effectively and dynamically.Represent that at its channel estimating node that network has not begun transmit operation in use the time obtains the use of whole backward channel.If a plurality of nodes place data on the network, then divide the visit of pairing backward channel according to the needs of these nodes.Do not refuse the visit to backward channel in the cycle of excessive number of any node, the visit of network is not wasted on the node of outgoing data yet.In addition, realize the use of backward channel and, stop any delay associated thus without the auxiliary operation of intermediary.
Another characteristics of the present invention are periodically to rotate the order that node is listened to backward channel.Therefore, usually all nodes are guaranteed the identical success rate transmitted on the backward channel.
More particularly description, accompanying drawing and appended claims by following preferred embodiment of the present invention will make aforesaid and other characteristics of the present invention and advantage will become obvious.
Summary of drawings
In order more completely to understand the present invention, its purpose and advantage, with reference now to following description and in conjunction with the accompanying drawings, wherein:
Fig. 1 is the diagram of the general topology of conventional multi-multipoint communication system;
Fig. 2 is the diagram according to the communication cycle of the embodiment of the invention;
Fig. 3 realizes the flow chart of acquisition to the method for access to netwoks according to inactive node that passes through of the embodiment of the invention;
Fig. 4 is the flow chart that central server realizes the CCA time slot allocation is given the method for inactive node that passes through according to the embodiment of the invention;
Fig. 5 is the flow chart according to the operation of the active node of the embodiment of the invention; And
Fig. 6 is the flow chart of the operation of active node in accordance with another embodiment of the present invention.
Embodiment
Describe preferred embodiment of the present invention referring now to Fig. 1-6, wherein same numeral is represented similar elements and is discussed in the realization environment of Internet Protocol multiple access (IPMA) system of local area network (LAN).But, can implement the present invention and come to provide information (for example, numerical data, or digitized voice) to application widely.In addition, the present invention can implement in other application and embodiment, as those of ordinary skill is understandable in the art.
The disclosure of the U.S. Patent application No.09/482054 that submitted on January 13rd, 2000 " System and Method forSingle-Point to Fixed-Multipoint Data Communication (be used for single-point to fixedly the system and method for multipoint data communication) " is combined in this for your guidance.
With reference to figure 2, the communication cycle 200 according to the embodiment of the invention is shown.Particularly, communication cycle 200 comprises forward channel (FC) interval 210, queried channel (QC) interval 220, clear channel assessment (CCA) (clearchannel assessment) interval 230 and backward channel (RC) interval 240.CCA interval 230 comprises N CCA time slot (slot) 235, and each all ad hoc distributes to specific node 130.FC at interval 210 is started and is included in the cycle 200 by central server 120 and wait for the packet that sends to one or more nodes 130 therebetween.FC at interval 210 overall width can be according to the data volume of waiting for and change with the cycle.Central server 120 be sent in FC at interval the sync mark 215 of 210 end so that to run through all movable nodes 130 of LAN synchronous.Therefore, each node 130 makes the appearance of the CCA time slot 235 of distributing to them coordinate mutually in time with respect to the appearance of sync mark 215.The interval as shown in the figure and the size of time slot, the length of ascending the throne, only be exemplary and can be configured to any required size.
QC is set at interval 220 allows to have to be sent but current these nodes 130 of CCA time slot 235 that are not assigned with such as data to central server 120 their existence of circular.As will describing in further detail, receiving inactive node when wishing to send the circular of data, central server 120 can be distributed to this node so that it is included in the communication cycle on the horizon with specific CCA time slot 235.The width at QC interval 220 is preferably fixed, but also can become with the cycle if necessary.
At FC 210 set time places after finishing at interval, for example at fixing QC at interval 220 when stopping, beginning CCA at interval 230.CCA at interval 230 comprises a large amount of CCA time slots 235, they be assigned to be currently connected to network and current in sending data, be those other nodes 130 of " activity ".Usually, " activity " node is at the node that sends data during the direct last cycle or in such as the one or more cycles in the cycle before the appointment in time limit a plurality of.In an embodiment of the present invention, CCA 230 is divided into a plurality of CCA time slots 235 that the duration equates at interval.Usually, dynamically distribute CCA time slot 235 to each node 130, it is listened to determine whether network is empty (free) during this period.CCA time slot 235 is followed in a continuous manner each other.
RC interval 240 results from after the CCA interval 230 and is a time period, and a node 130 ad hoc sends data in this time period.Normally, CCA at interval the grouping on the node 130 beginning backward channels of 230 (if having data to send) first nodes during self or highest priority send and continue by the time started and may RC duration of 240 at interval, the wherein CCA time slot 235 of first node first appearance in the consecutive order of CCA time slot.240 duration can change over nearly predetermined maximum time to RC at interval.RC 240 end is at interval represented by specific markers byte (not shown).For example, response identification specific markers byte, central server 20 begins to send data in the FC interval of the communication cycle of following.
All non-sending nodes 130 are listened to backward channel and are determined whether the grouping that is sent on the network is addressed to them.Have only a node 130 to allow on the backward channel of any given communication cycle, to send.Sending node 130 can send to a plurality of destinations with a plurality of groupings.The suitable mark of preferred use is described a plurality of groupings, and it is realized for the those of ordinary skill in the present technique field is conspicuous.Preferably, the data file of length is divided into the standard packet size and sends on a plurality of cycles.In an embodiment of the present invention, transmission and/or network layer place do not have affirmation mechanism.
Special characteristic of the present invention is only to distribute CCA time slot 235 to inactive node 130 by central server 120.Yet, inertia and be not assigned with those nodes of specific CCA time slot 235, such as node new or that do not connect before, or wish any node of logging in network (promptly in network, becoming activity), can be allowed the CCA time slot 235 that is distributed by communicating by letter with central server 120 during 220 at interval at QC.For example, with reference to figure 3, inactive node 130 is carried out method 300 according to the embodiment of the invention and is obtained the CCA time slot 235 that distributed.Particularly, inactive node 130 sign QC 220 beginnings (step 310) at interval.During QC interval 220, inactive node 130 sends to central server 120 (step 320) with node identifier (ID) grouping.Node ID grouping comprises that identification request central server 120 distributes the name of inactive node of CCA time slots and the node ID of address.Then, inactive node 130 is from central server 120 confirmations of receipt, and it comprises the identifier (step 330) of CCA time slot 235 of the special distribution of this node.Usually, this affirmation can send to inactive node 130 by central server 120 at interval at the FC of communication cycle that the next one is right after or communication cycle in the future.If adopted further conventional proof and safe practice before the distribution of CCA time slot, then the latter is necessary, and it is realized for the those of ordinary skill in the present technique field is conspicuous.During the CCA time slot 235 that distributes receiving, movable now node can identify the appearance (step 340) of its CCA time slot that distributes and listen to activity, makes node send its data thus when backward channel becomes sky.
During QC interval 220, wish that all inactive nodes of logging in network are attempted the node ID grouping is sent to central server 120.Because many nodes 130 may be attempted the node ID grouping is sent to server 120 simultaneously, so the probability of conflict (promptly misinformation is defeated) is very high.Therefore, in an embodiment of the present invention, can adopt conventional conflict to detect and avoiding method, its executive mode is conspicuous to those skilled in the art in the present technique field.For example, node may be listened to simultaneously to determine when and conflict occur during the node ID transmitted in packets, makes node carry out random back-off (back off) algorithm thus and resends the node ID grouping.
With reference to figure 4, the method for carrying out according to the embodiment of the invention at central server 120 places 400 is the node 130 distribution CCA time slots 235 of hope at network communication.Particularly, central server 120 sign QC 220 appearance (step 410) at interval.In this interim, central server 120 listener node ID transmission packets (step 420).Divide into groups if receive node ID, then 120 pairs of node scheduling time slots (step 430) that identified of central server during the CCA interval 230 of back to back or communication cycle in the future.During the FC interval 210 of suitable communication cycle, central server 120 will comprise that the affirmation of the scheduling of the time slot 235 that is assigned with sends to the node (step 440) that all are assigned with CCA time slot 235.In another embodiment of the present invention, central server 120 only will confirm to send to the node of those new activities and any node of its CCA time slot 235 that is assigned with of change.
According to embodiments of the invention, can cancel the CCA time slot 235 that is assigned with from node, if this node utilizes its chance of wheel to send data in pre-the specified time as yet during RC interval 240.Particularly, if central server 120 determines to offer an opportunity when using network specific node 130 own not utilizations, the distribution that then can recall CCA time slot 235 this node of stopping using during the cycle 200 of specific quantity.For example, central server 120 can send packet during next FC interval 210, and this packet comprises that this node no longer has the announcement of the CCA time slot 235 of distribution.Therefore the new scheduling of CCA time slot 235 can be sent to all remaining active nodes or only give those nodes of the influence of being dispatched variation.If the node of stopping using has the data of wishing to place on the network in the future, it just the suitable QC of the next one at interval in 220 to central server 120 its existence of announcement with request new CCA time slot 235 of distribution in CCA on the horizon interval 230.
Each node 130 is listened to the traffic on the network during the CCA of its appointment time slot 235, and if do not have the traffic (that is, not beginning as yet to send if having some other node of CCA time slot early) then this node can send data.More particularly, during CCA interval 230, the CCA time slot 235 of each node 130 its distribution is by the time listened to the traffic on the network.First node 130 (that is, central server 120 is distributed to the node 130 of the CCA time slot of its highest priority) is at first listened to.After a CCA time slot 235 stopped, Section Point 310 (that is, central server 120 is distributed to the node 130 of the CCA time slot of its second high priority) was listened to.Similarly, the n node is waited until the beginning of nCCA time slot 235 and is listened to.The node 130 that has data to send is just operated when only this node has been listened to network and determined not have other node 130 sending (promptly having clear channel) during the CCA of its appointment time slot 235.In an embodiment of the present invention, determine that during the CCA time slot that it distributed backward channel is that blank posterior nodal point 130 begins to send immediately.In other words, during CCA interval 230, produce transmission.In another embodiment, when occurring distributing to the CCA time slot of transmission receiver, node 130 begins transmission.In yet another embodiment of the present invention, sending node 130 waits for that the appearance at RC interval 240 begins the transmission on the backward channel.
In above-mentioned example,, also listen to and do not transmit with its CCA time slot 235 even network is this blank node if first node does not have data to send.Section Point begins to listen to during its CCA time slot 235, and whether the assessment network is blank.In this example, network be blank because the node with former time slot 235 without any data other node (promptly being assigned with the node of later time slot) also have no chance to send.If Section Point does not have data to send, then it is listened to and is the same as transmission with the mode of first node during its CCA time slot 235.But,, then after assessment network blank, carry out immediately if Section Point truly has data to send.According to embodiments of the invention, will send data at the time durations Section Point that distributes for the current appearance at RC interval 240 subsequently.Stop in case be used for the time of the 2nd CCA time slot 235, the node that then has later time slot is then listened to.Each all will detect Section Point and send data.Therefore, these later nodes determine that network is not that blank not attempting sends data during current communication cycle subsequently.
Have identical chance in order to ensure all nodes and send data on network, the order of CCA time slot allocation can be rotated with the cycle.Otherwise, have early that the node 130 (first and second nodes in the above-mentioned example) of the time slot 235 of order will always can use network and get rid of the node that other has the time slot of later appearance, and the node with later time slot may have no chance to use network in many cycles.The CCA time slot 235 that can adopt endless form that each communication cycle 200 is distributed by turns.For example, first listens to the node of listening at last in the previous cycle in next cycle, because its CCA time slot 235 moves to CCA 230 beginning at interval.The CCA time slot that moves each other node produced after the duration of a CCA time slot.On several cycles, the node 130 to each connection provides equal chance at first to send data by turns.Conspicuous as those skilled in the art in the present technique field, the distribution of time slot 235 and order change and can realize easily with other algorithm outside the above-mentioned recycle scheme.For supporting time inductive communication amount or need among little and consistent those embodiment that postpone, be very important characteristic to the equal visit of bandwidth.In addition, embodiments of the invention can be realized with other CCA structure of time slot.For example, can distribute predetermined and fixing CCA time slot to one or more nodes.Adopt this structure, if special applications needs, specific node can obtain priority.
In an embodiment of the present invention, the buffer size of active node 130 is by central server 120 monitoring.Particularly, the information type that is sent when voice transfer is bigger than other categorical data amount is very important.For example, the information that is sent can be divided into hard information and soft information.Hard information comprises speech data and soft information comprises the data such as internal command and internet data.In order to stop node to occupy backward channel with soft information always, central server 120 comprises the buffer size of soft information in each active node place monitoring.If central server 120 is determined the soft message buffer of nodes and is overstock the CCA time slot priority of (excessively) then node and have node switching than the low priority time slot.In other words, the CCA time slot of higher-priority (appear at CCA at interval 230 begin to locate those) preferably be assigned to the node that sends the hard information relative with soft information.To the CCA time slot of other node distribution that sends soft information than low priority.
During CCA interval 230, the traffic that each node is listened on the network determines whether other node sends.Determine not have other node to send if there is packet will send to take up an official post the what first node of its device of network, then this first node sends to its packet their destination in the time of being distributed, and sends specific markers byte representation RC subsequently and 240 finishes at interval.Because each node is all listened to all transmission that begin from any other node, so each other node all detects the transmission of first node and suppresses to send.
Fig. 5 illustrates the communication means of being realized by each node 130 500 according to the embodiment of the invention.In operation, node 130 receives the data (step 510) that sent by central server 120 during FC interval 210.When receiving sync mark 115, node 130 is determined the time (step 520) that CCA time slot 235 that it distributes produces according to the priority of the time of reception of sync mark and the CCA time slot 235 that distributed.According to this time of determining, node 130 is waited for the CCA time slot 235 that it distributes.Suitable when being assigned with the CCA time slot when occurring, node 130 determines whether networks are blank (steps 540).If network is not blank, then node 130 is listened to the grouping (step 550) that is addressed to it on the backward channel.If network is blank, then node 130 determines whether it has data (step 560) and will send (step 570) on backward channel.If there are not data to send, then node 130 enters listen mode (step 550).
As long as periodically send data, movable node need not by their existence of sending node ID packet acknowledgement.For example, central server 120 is followed the tracks of the availability at RC interval 240 and the communications between the monitor node 130.But, if having data in the cycle of predetermined quantity, node do not wish to keep connecting, then can send pseudo-grouping, promptly be not addressed to the grouping of any specific node 130.Fig. 6 illustrates the communication means 600 according to the embodiment of the invention of realizing pseudo-grouping.Communication means 600 is consistent with communication means 500, except two additional steps.Particularly, after node 130 determined that (step 560) do not have data to send, this node determined whether (step 610) keeps its CCA time slot that distributes, and promptly keeps connecting.If node wishes to keep connecting, then it sends (step 620) pseudo-packet.Otherwise node 130 is listened to (step 550) and is addressed to its grouping.
In an embodiment of the present invention, be provided with guard time regulate with the embodiment delay associated and with each embodiment be optimized to this embodiment specification (for example, minimum error rate, minimum lock in time, or the like).Guard time preferably places FC interval 210, RC interval 240 and CCA 230 beginning and end at interval.But other configuration also can be used to regulate aforementioned and other delay.As above prompting, the present invention can dispose design implementation with various application, topological sum.Each embodiment with need to the compensation of the delay of the frequency switching of the relevant propagation delay (function of euclidean distance between node pair) of transmission and relevant with circuit (hardware), processing and node.The skilled artisan in the art will understand and how calculate and measure this time of delay.
According to the present invention, each node determines whether to send data by monitoring CCA time slot 235.In this, embodiments of the invention need not central server 120 and come intermediary and at interval 240 the visit to RC between the various nodes 130 is provided.Therefore, can avoid any propagation delay relevant with intermediary.
Though illustrate and described the present invention especially with reference to several preferred embodiments, but those skilled in the art are appreciated that the spirit and scope of the present invention that can carry out the various variations on form and the details and not deviate from appended claims and limited in the present technique field.
Claims (36)
1. a system is characterized in that, comprising:
The communication medium of sharing;
Server is connected to described shared communication medium and can sends forward channel signal on described common share communication media in the predetermined forward channel interval of communication cycle; With
A plurality of nodes, each described node all is connected to described common share communication media and can monitors described forward channel signal, employed described common share communication media during the clear channel assessment time slot of monitoring in the clear channel evaluation interval of described communication cycle, and, the employed described common share communication media of monitoring during described clear channel assessment time slot determining to provide reverse channel signals when described common share communication media is blank owing to making described node
Wherein said clear channel evaluation interval is divided into a plurality of clear channel assessment time slots, and each clear channel assessment time slot is given a described node by specific assigned.
2. the system as claimed in claim 1 is characterized in that, described server can receive described reverse channel signals and wherein each node can both receive described forward channel signal.
3. the system as claimed in claim 1 is characterized in that, described forward channel signal and described reverse channel signals comprise packet.
4. the system as claimed in claim 1, it is characterized in that, described forward channel signal comprises an address, and each node is assigned to unique node address and is received in information encoded on the described forward channel signal when can be in the described address of described forward channel mating with the described unique node address that is assigned with.
5. system as claimed in claim 4 is characterized in that node address is an Internet Protocol address.
6. the system as claimed in claim 1 is characterized in that, each described clear channel assessment time slot is the duration that equates.
7. system as claimed in claim 6 is characterized in that, described server dynamically distributes described clear channel assessment time slot to described node.
8. system as claimed in claim 7 is characterized in that, the distribution of described clear channel assessment time slot is rotated in a looping fashion.
9. the system as claimed in claim 1 is characterized in that, provides described reverse channel signals in predetermined backward channel interim.
10. system as claimed in claim 9 is characterized in that, also comprises guard time, and it separates described forward channel interval, described backward channel interval and described clear channel evaluation interval.
11. the system as claimed in claim 1 is characterized in that, when finishing the described forward channel signal of transmission, described server can send synchronizing signal.
12. system as claimed in claim 11 is characterized in that, described synchronizing signal is sync mark.
13. system as claimed in claim 11 is characterized in that, each described node can both calculate and described synchronizing signal occur and time interval between its clear channel of distributing assessment time slot occurs.
14. system as claimed in claim 9 is characterized in that, described server can be monitored described shared communication medium in queried channel interim of described communication cycle.
15. system as claimed in claim 14 is characterized in that, described queried channel betide at interval described forward channel at interval after and described backward channel at interval before.
16. system as claimed in claim 14 is characterized in that, also comprises:
At least one inactive node, wherein said inactive node can be in described queried channel interim sending node ID grouping, and described node ID grouping comprises the identifier that identifies described inactive node.
17. system as claimed in claim 16 is characterized in that, described server can distribute clear channel assessment time slot to described inactive node.
18. the system as claimed in claim 1 is characterized in that, is inactive if described server is determined node, then described server can be cancelled the clear channel assessment time slot of node.
19. in system, a kind ofly be used for multi-multipoint method for communicating with common share communication media, server and a plurality of nodes, it is characterized in that, said method comprising the steps of:
Send forward channel signal from described server at described common share communication media;
Each place at a plurality of nodes monitors described common share communication media for forward channel signal; And
Each place at a plurality of nodes monitors described common share communication media for reverse channel signals, and each of wherein said a plurality of nodes is all monitored in the assessment of the clear channel in the clear channel evaluation interval time slot,
If described backward channel with a plurality of nodes in a relevant described clear channel assessment time slot during be blank, and one in described a plurality of node has information and will send to server as reverse channel signals, just from described a plurality of nodes sends reverse channel signals
Wherein described clear channel evaluation interval is divided into a plurality of clear channel assessment time slots, each clear channel assessment time slot is given a described node by specific assigned.
20. method as claimed in claim 19 is characterized in that, each described clear channel assessment time slot has the equal duration.
21. method as claimed in claim 19 is characterized in that, comprises that also clear channel is assessed time slot dynamically distributes to each step in a plurality of nodes.
22. method as claimed in claim 21 is characterized in that, described clear channel assessment time slot is assigned with in a looping fashion.
23. method as claimed in claim 19 is characterized in that, provides described forward channel signal in predetermined forward channel interim, and provides described reverse channel signals in predetermined backward channel interim.
24. method as claimed in claim 23 is characterized in that, also is included in described forward channel interval, described backward channel interval and the middle step that guard time is provided of described clear channel evaluation interval.
25. method as claimed in claim 19 is characterized in that, comprises that also the synchronizing signal by being sent by server makes described server and the synchronous step of a plurality of node.
26. method as claimed in claim 25 is characterized in that, also is included in each described node place and calculates the step that described synchronizing signal occurs and the time interval between its clear channel of distributing assessment time slot occurs.
27. method as claimed in claim 19 is characterized in that, also is included in described server and is in queried channel interim and monitors the step of described common share communication media.
28. method as claimed in claim 27 is characterized in that, also comprises:
Divide into groups from inactive node sending node ID in described queried channel interim, described node ID grouping comprises the identifier that identifies described inactive node.
29. method as claimed in claim 28 is characterized in that, also comprises clear channel is assessed the step that time slot allocation is given described inactive node.
30. method as claimed in claim 19 is characterized in that, also comprises if it is inactive that described server is determined node, then cancels the step of the clear channel assessment time slot of node.
31. a communication cycle form that is used for providing data communication in multi-multipoint communication system, wherein said communication system comprise that to server of major general and a plurality of node communications medium interconnecting it is characterized in that, described communication cycle form comprises:
The forward channel interval, wherein said forward channel has been specified the time period that is used for sending from described server forward channel signal at interval;
The clear channel evaluation interval, wherein said clear channel assessment (CCA) is divided into a plurality of clear channel assessment time slots at interval, each clear channel assessment time slot is given a described node by specific assigned, and described clear channel evaluation interval has specified node to listen to the time period of described communication medium;
The queried channel interval, wherein said queried channel has been specified a time period at interval, makes the node that is not assigned to clear channel assessment time slot distribute clear channel assessment time slot to described server requests; With
The time period that is sent reverse channel signals by a described node has been specified at backward channel interval, wherein said backward channel at interval.
32. communication cycle form as claimed in claim 31 is characterized in that, the described forward channel duration at interval is variable.
33. communication cycle form as claimed in claim 32 is characterized in that, also comprises
Synchronizing cycle, specified the time period when described server sends synchronizing signal wherein said synchronizing cycle, when described forward channel signal was finished during described synchronizing signal was represented communication cycle.
34. communication cycle form as claimed in claim 33, it is characterized in that, the described queried channel duration is at interval fixed, and described synchronizing signal makes each described node be assigned to a clear channel assessment time slot to calculate the appearance of the described clear channel assessment time slot that is assigned with.
35. communication cycle form as claimed in claim 31 is characterized in that, the described backward channel duration at interval is variable.
36. communication cycle form as claimed in claim 31 is characterized in that, described queried channel occurs between described forward channel interval and the described clear channel evaluation interval at interval.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US30615901P | 2001-07-19 | 2001-07-19 | |
| US60/306,159 | 2001-07-19 |
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| CN1555634A true CN1555634A (en) | 2004-12-15 |
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| CNA028180879A Pending CN1555634A (en) | 2001-07-19 | 2002-07-19 | System and method for multipoint to multipoint data communication |
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| CN (1) | CN1555634A (en) |
| EA (1) | EA005625B1 (en) |
| NZ (1) | NZ530993A (en) |
| WO (1) | WO2003009518A2 (en) |
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| WO2009089697A1 (en) * | 2008-01-15 | 2009-07-23 | Corpware Systems Limited | A kind of network plane, a station and a method for realizing the multiple stations cooperation service on them |
| CN103177274A (en) * | 2013-03-04 | 2013-06-26 | 珠海同方爱德科技有限公司 | Anti-collision method of multiple radio frequency identifying readers based on time slots |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2016048798A1 (en) * | 2014-09-25 | 2016-03-31 | Nokia Technologies Oy | Listen before talk arrangement for a multi-operator scenario |
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|---|---|---|---|---|
| US4628311A (en) * | 1983-10-19 | 1986-12-09 | International Business Machines Corporation | Carrier sense multiple access with collision avoidance utilizing rotating time staggered access windows |
| US5231634B1 (en) * | 1991-12-18 | 1996-04-02 | Proxim Inc | Medium access protocol for wireless lans |
| US5276703A (en) * | 1992-01-13 | 1994-01-04 | Windata, Inc. | Wireless local area network communications system |
| EP0632619B1 (en) * | 1993-06-30 | 2000-10-18 | Cabletron Systems, Inc. | Collision reduction method for ethernet network |
| US6026095A (en) * | 1994-09-27 | 2000-02-15 | 3Com Corporation | Method and apparatus for controlling latency and jitter in shared CSMA/CD (repeater) environment |
| US5774658A (en) * | 1996-09-17 | 1998-06-30 | Advanced Micro Devices, Inc. | Arrangement for accessing media in a network having universal multiple access nodes and carrier sense nodes |
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2002
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- 2002-07-19 CN CNA028180879A patent/CN1555634A/en active Pending
- 2002-07-19 NZ NZ530993A patent/NZ530993A/en unknown
- 2002-07-19 WO PCT/US2002/023211 patent/WO2003009518A2/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2009089697A1 (en) * | 2008-01-15 | 2009-07-23 | Corpware Systems Limited | A kind of network plane, a station and a method for realizing the multiple stations cooperation service on them |
| CN103177274A (en) * | 2013-03-04 | 2013-06-26 | 珠海同方爱德科技有限公司 | Anti-collision method of multiple radio frequency identifying readers based on time slots |
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| WO2003009518A2 (en) | 2003-01-30 |
| WO2003009518A3 (en) | 2003-07-17 |
| EA005625B1 (en) | 2005-04-28 |
| EA200400206A1 (en) | 2004-08-26 |
| NZ530993A (en) | 2006-07-28 |
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