Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q11/00—Selecting arrangements for multiplex systems
  • H04Q11/04—Selecting arrangements for multiplex systems for time-division multiplexing
  • H04Q11/08—Time only switching
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13034—A/D conversion, code compression/expansion
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13098—Mobile subscriber
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13141—Hunting for free outlet, circuit or channel
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13292—Time division multiplexing, TDM
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13332—Broadband, CATV, dynamic bandwidth allocation
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04Q—SELECTING
  • H04Q2213/00—Indexing scheme relating to selecting arrangements in general and for multiplex systems
  • H04Q2213/13367—Hierarchical multiplexing, add-drop multiplexing

Definitions

• the present invention relates to a method of routing messages between access points. It is more particularly used in the field of telephony for the production and improvement of switching exchanges. It is in particular usable, in an improvement, in the field of mobile telephony.
• the object of the invention is to reduce the cost of telephone exchanges.
• Circuit switching systems amount to establishing, between two access points to be connected, a physical circuit, a pair of copper wires, a fiber optic link with all the necessary equipment or another permanent link.
• This permanent link is left entirely available to subscribers located on either side of the two access points to be linked. Under these conditions, they can exchange information on this line at their disposal with as high a speed as they wish, to the extent that, technologically speaking, this available link allows it.
• a network between multiple access points is organized and the connection between one subscriber and another via this network takes, at a given time, a channel in a channel of this network.
• a channel can thus be defined as a reservation of a time window of a frame, as an allocation of a frequency bandwidth in a global band, or both simultaneously. It can also be defined as a temporary assignment of a coding law in a coded division multiple access (CDMA) multiple access channel.
• CDMA coded division multiple access
• routers are installed at each node in the network. Each time these routers receive a fraction of a message to be transmitted, they extract from this message the address part and assigns to this message, to transmit it further on (generally towards the subscriber), a channel which connects this router to another router to transmit a packet of information contained in this message. Then the message with its information packets progresses in the network and is finally transmitted on the line of the recipient subscriber.
• the second system has the advantage over the first that the infrastructure to be put in place is much less important.
• this results in a permanent need, for each packet of information to be transmitted from one subscriber to another, to extract the address of the recipient, to determine a path by which this packet of information must be transmitted further and insert this information packet into a channel of a channel corresponding to this path.
• the determination of the path involves the designation of time windows, bandwidths, coding keys and, most of the time, destination routers in which the rest of the routing processing will be carried out.
• the conditions of use of the network, the cessation of a communication between two subscribers and the establishment of a communication between two new subscribers lead to the fact that the routing of messages between the connected subscribers is constantly changing, constantly reorganized .
• the invention relates to this reorganization.
• the realization of the routers requires the installation in the access points, one also says the nodes, of electronic circuits of commutation and transmission capable of constituting on demand channels and channels of transmission in sufficient number for communications to route.
• the problem of producing these electronic circuits is that of optimizing the hardware means used, of the minimum number of these electronic circuits necessary for a nominal number of communications to be routed.
• the most important problem to be solved is that of the optimized use of the channels.
• the circuits of such a router include time multiplexing circuits in insertion and time demultiplexing circuits in extraction.
• a channel is used for communication between an access point A and an access point B.
• this time insertion multiplexer is produced on an electronic card. If, for statistical reasons at a given moment, there is only one message left which must be exchanged between a router A and a router B, the channel must nevertheless be maintained.
• Document US-A-4,718,058 also discloses a channel switching system in which messages of reduced size are concatenated together to occupy an entire channel in a channel, a virtual link between two access points.
• This approach which is ultimately similar to the establishment of channels in a channel between two access points tends to solve the problem of non-optimal use of the channels.
• the expected material gain which could be for example of the order of four insofar as four messages are concatenated, with a speed at 8 Kbits / s to form a global message at 32 Kbits / s (and which would use a channel of channel), is in fact illusory.
• the material gain observed rather than being a 4 to 1 ratio is only a 1.3 to 1 ratio. Indeed, the statistical phenomena of occupation and the diversity of occupancy requests make the channels underused, and therefore require significant use of tamping.
• the gain goes from 1, 30 to 1 to 3 or 4 to 1, on average to 3.5 to 1.
• the example treated will be that of the constitution of channels at 32 Kbits / s from 8 kbit / s outgoing channels.
• the theoretical limits are almost approached with the invention.
• the reorganization carried out in the invention consists in moving an allocation, devolved to a message, from a time window of a channel to a time window, for example of the same rank, in another channel, in order to free a channel and therefore the electronic circuits which correspond to it. In these conditions this freed channel can be used to create communications with other access points.
• the subject of the invention is therefore a method of routing messages between access points in which
• a framing is constituted and a group by time multiplexing of messages originating from various origins according to frames of this framing
• channels are established between a first and a second access point, a channel thus established having a nominal capacity in number of messages,
• FIG. 1 a schematic representation according to the invention of a routing circuit, or router, mounted in an access point, receiving messages and which is intended to transmit them to other access points;
• FIG. 2 a representation of a screening created to allow an exchange between access points;
• Figure 3 the representation of the material means necessary to set up in the access points, and of the channels that these material means make it possible to institute between different routers.
• Figure 1 shows a system usable for implementing the message routing method of the invention. It essentially shows an access point A.
• the access point in practice is geographically located at a place in a territory. For example, it is a telephone exchange in a small town or a district of a large town, or possibly a relay center installed at a routing node of a network.
• Access point A is equipped with circuits to allow it to form channels with other access points, for example here access points B, C or D.
• the circuits available for this purpose in the routing circuits at the access point A will in one example include N time multiplexers. In an example to simplify N will be 10. These multiplexer circuits include N combination circuits such as 1 connected at input to N delay circuits 2.
• the delay circuits 2 each comprise L delay lines such as 3, programmable, making it possible to constitute, in a given framing, frames of L messages.
• the N combination circuits such as 1 each have an output 4 connected to an input of a switching circuit 5 which makes it possible to connect the output 4 to a line, for example physical, 6 to 8.
• the lines 6 to 8 allow d '' forward messages from access point A to access points B or C or D respectively. Circuit 5 makes it possible to make a choice between these lines, and therefore to choose a destination.
• the symbolic representation of Figure 1 can take various material forms. Possibly the physical lines 6 to 8 may themselves be only channel channels with an even higher speed.
• Corresponding equipment is created in access points B, C and D. It will already be noted that, for a number N of multiplexers, the possible number of access points B, C or D should itself be limited to N At least in practice, because if this is not the case, it is possible that an access point is the recipient of a communication and that no channel can be allocated to this call given that all the channels would have been allocated to the other destinations.
• a processing processor 9 issues orders O to the circuits 1, 2 and 5 and is connected for this purpose by a bus 10 to these circuits, to a program memory 11, to a data memory 12 and to a clock 13.
• the program memory 11 comprises a program 14 which, in a known manner, comprises a multiplexing subroutine 15.
• Figure 2 shows the constitution of a screening.
• frames of 125 ⁇ s are each made up of 32 time windows.
• these messages come from mobile telephones 16.
• an uplink is shown, from a mobile telephone 16 to a base station 17 connected itself, downstream in the network, to the access point (to the network node ) A.
• the mobile telephones 16 comprise, for this uplink, in the case where the message is a speech message, a microphone 18 connected to an analog-digital sampler-converter 19.
• the sampler-converter 19, of in a conventional manner, is clocked by a signal at 8 kHz without there being any a priori parallel between this sampling rate of the speech signal and the rate imposed on the routing circuit of the access point A.
• D ' in a known manner, the sampler-converter 19 produces 13-bit words per sample.
• FIG. 3 shows, for the N multiplexers of FIG.
• each of the N multiplexers of A is capable of establishing a link with the access point B.
• N x (L - 1) communications cease and that however a communication persists occupying a channel in each channel between A and B then the N multiplexers continue to be all occupied (to route each a single message!). All the resources of access point A are then used. Under these conditions, a next communication which must be created cannot be carried out if the corresponding message must be routed on an access point C.
• this message must be routed on the access point B this message will be naturally incorporated in one of the channels already established between A and B. But as statistically the request to the access point C is possible this amounts to having to create additional multiplexers.
• the total of the multiplexers (and electronic cards) then becomes a greater number than N to equip the access point A.
• These additional multiplexers are essential although this access point A already has a nominal capacity of N x L communications.
• the number of multiplexers is of the order of N x L x 3 when we would like it to be of the order of N only.
• the channels established between the first access point A and the second access point B are monitored. And for all the channels thus identified, the number of messages, the number of channels actually used in each of these is measured. canals.
• a record of a database can be assigned to each of the institutable channels, comprising a channel name on the one hand and a channel name on the other hand, and L additional fields corresponding to each record in this database an indication 24 mentioning the occupation of a corresponding channel in this channel.
• memory 12 there are as many databases as there are links between different possible access points. For example in this case there will be three, one for the connection between A and B, one for the connection between A and C and one for the connection between A and D.
• this monitoring is not complicated to implement since the processor 9 allocates, by virtue of the multiplexing program 14, the different time windows of the channels to the messages to be transmitted. Therefore memory 12 and the databases it contains are already available in the state of the art, at least in an implicit manner.
• a monitoring program 25 therefore makes it possible to identify for a link between two access points, for example A and B, the number of occupied time windows as well as the number of channels formed among the N different multiplexers. This is preferably done in each of the links, AB, AC, or AD. Then we look for a number of communications thus effectively exchanged if this number is less than a nominal capacity of all the channels instituted minus one. Ultimately, in the case where all the multiplexers are capable of M communications (which a priori is not an obligation), we see if the number of communications for M channels is not less than L x (M - 1 ). If so, this means that at least the equivalent of one channel can be saved by rearranging the channels in those channels.
• the invention is reorganized by applying the program 25.
• it is preferably sought which is the least occupied channel.
• M be this channel.
• the reorganization comprises in principle that a channel using a time window 26 of the channel of the multiplexer M is transferred in another channel, for example the channel of the multiplexer 1, to a time window 27 posterior (or anterior to the time window 24) .
• window 27 has in this channel of multiplexer 1 the same time position as that which it occupied in channel M. So step by step you can transfer the communications routed by one channel (and therefore by a given multiplexer) to another channel.
• the channel that we decide to release will be the channel that will have the fewest messages transmitted.
• the reception channels are preferably the busiest channels among the M - 1 remaining channels.
• the content of time window 26 should be stored. , at moment of transfer, for a duration greater than the duration of the frame.
• channel 26 appears, seen from node A, as a channel which ceases to exist in favor of another channel 28 created.
• This new channel created 28 is of course, in a known manner, assigned to one of the channels already existing between the access point A and the access point B.
• the channel M is eliminated in order to retain only M - 1.
• the least busy channel here the channel M, is sought, and then the reuse of this channel is prohibited as long as the M - 1 other channels established are not all complete.
• the control circuits of the access point A send by means of a hand-over program 30, HO, to the base stations 17 and / or 29, or possibly to a general management circuit for these base stations, a signal S constituting a transfer order. More precisely, the signal S will appear as a transfer request. This request does not need to be satisfied immediately. It can be satisfied one or more frames later. What matters is that overall for a long period, in particular that of the conversations exchanged with mobile phones, the data specific to these communications are routed on a compacted channel and not on very diverse and underemployed channels. If necessary, the occupation of another channel during the same frame 22 for another channel but for the same communication can occur before the release of the channel M.

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• Engineering & Computer Science (AREA)
• Computer Networks & Wireless Communication (AREA)
• Time-Division Multiplex Systems (AREA)
• Data Exchanges In Wide-Area Networks (AREA)
• Mobile Radio Communication Systems (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=9547251

Family Applications (1)

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• 1999
  • 1999-06-24 FR FR9908074A patent/FR2795593B1/fr not_active Expired - Fee Related
• 2000
  • 2000-06-22 EP EP00948056A patent/EP1108304A1/de not_active Withdrawn
  • 2000-06-22 AU AU61643/00A patent/AU6164300A/en not_active Abandoned
  • 2000-06-22 WO PCT/FR2000/001737 patent/WO2001001616A1/fr not_active Application Discontinuation
  • 2000-06-22 CN CN 00801194 patent/CN1315088A/zh active Pending

Non-Patent Citations (1)

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