Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W88/00—Devices specially adapted for wireless communication networks, e.g. terminals, base stations or access point devices
  • H04W88/02—Terminal devices
  • H04W88/022—Selective call receivers
  • H04W88/025—Selective call decoders
  • H04W88/026—Selective call decoders using digital address codes

Definitions

• the invention relates to the transmission of digital information between at least one transmitting station and a plurality of receivers, using sub-carriers of radio frequency channels as well as an asynchronous packet transmission protocol containing
• an asynchronous transmission protocol n is, by definition, not synchronized on a predetermined time basis. Consequently, the information receivers operating on this type of asynchronous protocol must remain permanently on so as to be able to acquire, at any time, which by definition 5 is not known in advance, digital information who are intended.
• the invention aims to provide a solution to this problem.
• the invention therefore provides a method for increasing the autonomy of digital information receivers, in which the information is transmitted from at least one fixed station by sub-carriers of radio frequency channels using an asynchronous packet transmission protocol each containing a predetermined number of elementary blocks.
• At least one specific channel is selected from the radiofrequency channels so as to materialize at least one specific identifiable transmission network.
• a transmission frame comprising a predetermined number of successive packets is defined within the transmission protocol carried by this network.
• a specific elementary packet identification block is inserted into each packet of the frame, at a predetermined location, containing an identifier of the rank of the packet in the frame.
• elementary network signaling blocks containing at least one network identifier are inserted in successive frames, and mutually separated by a variable number of elementary blocks less than the number of blocks in a packet.
• the number of blocks in a packet leads to a transmission duration of said packet of approximately 5 seconds
• the "variable" nature of the number of elementary blocks separating two successive network signaling blocks means that this number is not necessarily fixed and predetermined in advance (although it may be) but may possibly vary during transmission, provided, of course, that the corresponding duration of spacing remains less than a maximum duration fixed in advance which must in any case be less than the transmission time of a packet.
• a network indication and a group indication corresponding to a packet rank in said frame are stored in each receiver.
• the method according to the invention comprises a first step, known as acquisition, in which each receiver detects the specific transmission channel by testing the presence of a network signaling block containing a network identifier corresponding to said stored network indication. in the receiver. Then, the receiver being tuned to said specific transmission channel, it analyzes the rank identifier contained in the next packet identification block.
• the method furthermore comprises a synchronization step in which, the receiver being locked onto said specific transmission channel, and moreover having an idle state and an active state, the setting in the active state of each receiver on time is synchronized successive occurrences of packet identification blocks whose rank identifiers correspond to the group indication stored in the receiver.
• the invention therefore applies in a particularly advantageous manner to paging and makes it possible, from an asynchronous transmission protocol, to synchronize the alarms of paging receivers at successive instants temporally spaced by the same time interval. .
• the fact of inserting in the successive frames, separate network signaling blocks with a spacing duration less than or equal to a predetermined maximum duration (for example 0.5 seconds), itself less than the transmission time of a packet (typically 5 seconds) makes it possible to accelerate the acquisition of the transmission network by the receivers, and therefore the synchronization of their sleep and wake cycles, which considerably increases the autonomy of these receivers.
• a predetermined maximum duration for example 0.5 seconds
• each packet identification block at any predetermined place in the packet, in particular if the type C packets described in the SWIFT document, it is particularly advantageous, in particular to minimize the risk of losing messages intended for certain receivers, to insert each packet identification block at the start of each packet.
• the receiver in the acquisition step, the receiver is wedged on one of the transmission networks and the test is carried out, at most during a test duration equal to said predetermined maximum duration (0, 5 seconds for example), the presence, on this channel, of a network signaling block containing a network identifier consistent with said network indication and, if the test result is negative at the expiration of said test duration , the receiver searches for another transmission channel to carry out a new test.
• the receiver is put in its idle state until the reception of the next packet identification block. This further increases the autonomy of the receivers.
• the receiver can be kept in its active state after analysis of the content of the network signaling block until the reception of the next packet identification block. It is particularly advantageous to subdivide each group of receptors into several subgroups. In addition, an indication of the subgroup to which the receiver belongs is then stored in each receiver. At least one identifier of a designated subgroup belonging to the group corresponding to this packet identification block is inserted into each packet identification block. And, in the synchronization step, we place in their idle state, after analysis of the content of the packet identification block, all the receivers whose sub-group indications do not match with the sub-identifier (s) designated groups.
• the subdivision of a group of receptors into several subgroups allows to put the receivers whose subgroups are not designated at the start of each packet, in particular because no message is intended for them in their idle state, which further increases the autonomy of these receivers.
• Several specific identifiable transmission networks can be materialized. Transmission networks can be changed during the actual transmission. Also, in the event of a network modification during transmission, the new network identifier is inserted into the network signaling blocks and advantageously is inserted into the packet identification blocks specific network modification information. For example, a specific bit is set to 1.
• all the receivers of the group associated with the corresponding packet identification block are forced to remain in their active state after analysis of the content of the identification block. at least until the reception and analysis of the content of the next network signaling block, so that they can determine the new transmission network and stall there.
• an elementary message signaling block containing the address of a receiver intended to receive a message is inserted into a transmission packet, after the packet identification block. 'a time indication relative to the message start time.
• the receiver After analysis of the content of the message signaling block, the receiver can possibly be placed in an idle state until the message is received.
• the time indication may specify that the message itself will be located later in the same packet, or else in a next packet.
• a greater number of messages than a packet can contain may have to be sent. This difficulty is resolved by the use of the indirect mechanism constituted by the insertion of message signaling blocks.
• the message signaling block is sent to designate the useful data of the message and also comprises a particular bit (flag) indicating whether the designated message is delayed or not.
• the receiver can go into its idle state after analysis of the content of the message signaling block and then wake up each time reception d a packet identification block, even if this packet identification block does not correspond to its group, to check whether this packet identification block contains a subgroup identifier corresponding to its subgroup. If this is the case, the receiver will then analyze the new message signaling block indicating the place of this message proper in this current packet.
• the invention also relates to a digital information transmission system, comprising at least one fixed station transmitting information by sub-carriers of radio frequency channels using an asynchronous packet transmission protocol each containing a predetermined number of elementary blocks , and several receivers comprising means for radio frequency reception and means for processing the data received.
• the station includes generation means capable of generating, within the transmission protocol carried by at least one specific identifiable transmission network, materialized by at least one specific transmission channel selected from said channels radio frequency, successive transmission frames each comprising a predetermined number of successive packets.
• the station also includes insertion means for inserting into each packet of the frame, at a predetermined location, a specific elementary packet identification block containing an identifier of the rank of the packet in the frame, and for inserting into the frames of the network signaling elementary blocks containing at least one network identifier, these network signaling blocks being mutually separated by a variable number of elementary blocks less than the number of blocks in a packet.
• Each receiver has a memory containing a network indication and a group indication corresponding to a packet rank in said frame.
• the receiver processing means have an active state and a rest state and include test means capable of testing, for each transmission channel received by the reception means, the presence of a network signaling block containing an identifier network matching said network indication and then analyzing the rank identifier contained in the next packet identification block.
• the receiver processing means furthermore comprise control means able to synchronize temporally the setting in the active state of each receiver set on said specific transmission channel, on the successive occurrences of packet identification blocks containing identifiers of rank corresponding to a group indication stored in the receiver.
• the memory of each receiver also contains an indication of the subgroup to which the receiver belongs.
• the station insertion means then insert into each packet identification block at least one identifier of the designated subgroup of the group corresponding to this identification block.
• the control means of all the receivers whose sub-group indications do not match the designated sub-group identifier (s) place said receivers in their idle state.
• the receiver processing means are capable of analyzing the content of the packet identification blocks corresponding to their group and, in the presence in said identification blocks of specific modification information network, the control means of all the receivers in the group, associated with the corresponding packet identification block, force these receivers to remain in their active state at least until the reception and analysis of the next signaling block of network.
• FIGS. 1 to 4 very schematically represent a structure of elementary blocks usable according to the invention in accordance with a SWIFT transmission protocol
• FIG. 5 very schematically illustrates the internal architecture of a receiver according to the invention
• FIG. 6 very schematically illustrates the internal architecture of a station according to the invention
• FIG. 7 is a schematic flow diagram of an embodiment of a method according to the invention.
• FIG. 8 and 9 illustrate time diagrams relating to the operation of a receiver in two particular cases of transmission.
• the invention is not limited thereto, we will now rely in the example which will be described, on an asynchronous transmission protocol of the type described in the SWIFT document. On effect, such a transmission protocol allows a high net speed of information transmission, typically between 6 kilobits / s and 10 kilobits / s, which is particularly useful for the transmission of voice messages.
• each elementary block BLC comprises (FIG. 1) a BIC identifier followed by an AND header indicating the type of the block.
• the header is followed by a useful part DU containing the data proper of the BLC block.
• This useful part DU is followed by CRC error correction bits and PRY parity bits.
• Each of these blocks comprises a total of 288 bits.
• the transmission time of a packet is typically of the order of 5 seconds.
• This asynchronous transmission protocol is carried by a subcarrier (centered around 76 kHz) of radio frequency channels, typically located in the FM band.
• At least one specific identifiable transmission network is materialized by selecting from said radiofrequency channels at least one specific channel.
• a transmission network can use several radio frequency channels.
• several identifiable transmission networks can be defined.
• a transmission frame comprising a predetermined number of successive packets, for example sixteen packets, is then defined for this transmission protocol according to the invention.
• a specific BLTS packet identification block ( Figure 3) identified by a specific digital word ET2 (for example on five bits) of the head AND.
• This BLTS identification block contains, in the DU part, an IR identifier making it possible to identify the rank of this packet, in other words its position, in the frame.
• this IR rank identifier will make it possible to designate a group of receptors.
• DU includes a binary word MSF allowing to designate, within the group of receptors, subgroups of receptors.
• MSF binary word
• a word of 128 bits will be chosen respectively assigned to 128 subgroups of receivers.
• the logical value of each bit of this MSF word indicates whether the receivers of the corresponding subgroup are likely to receive a message.
• BLNS network signaling blocks (FIG. 2) are also inserted in the successive frames, the type of which is identified by a specific word ET1 in the header ET.
• This BLNS block contains at least one NWD network identifier defining the characteristics of the transmission network, and in particular the frequency of the transmission channel.
• these BLNS blocks are inserted by the transmitting station in the successive transmission frames so that they are mutually spaced from a maximum number of elementary blocks of any type, whether they are BLC type blocks, BLTS blocks or other types of blocks.
• This maximum number corresponding to a predetermined maximum spacing duration, typically 0.5 seconds, less than the duration of transmission of a packet.
• the spacing time between two consecutive BLNS blocks may vary provided that it remains less than the maximum duration. It is in fact the means of insertion of the station which decide on the insertion of these BLTS blocks in the successive frames. It should therefore be noted here that the insertion of BLNS blocks takes place in a completely asynchronous manner with respect to the insertion of BLTS blocks.
• the invention also provides for using another specific BLMS elementary block which is in fact a message signaling block (FIG. 4) and whose type ET3 appears in the AND header.
• This BLMS block contains in the useful part DU the address ADR of the receiver for which a message is intended, as well as a time indication DFS relative to the instant of start of message. If the message is transmitted in the same packet as that containing the BLMS block, this DFS indication defines for example the rank of the first block of the message proper, intended for the receiver, relative to the start of the packet. This DFS time indication can also indicate that the actual message intended for the receiver will be transmitted not in the packet containing this BLMS block, but in a subsequent packet.
• FIG. 5 represents the internal architecture of an RC receiver according to the invention
• this receiver for example an autonomous portable paging receiver
• This antenna is connected to reception means 1 comprising, at the head, a high frequency stage 10, followed by a specific filtering circuit 11 allowing to extract the SWIFT subcarrier.
• This filtering stage is itself connected to a decoder, for example that marketed by the Japanese company OKI under the reference MSM 9553 and capable of delivering at output, after error correction and parity check, the elementary blocks freed in particular of CRC and PRY bits.
• the reception means also comprise a specific circuit, not shown here for the purposes of simplification, research and automatic control of the frequency of the carrier signal, so as to be able to lock onto one of the transmission channels.
• the output of the reception means is connected to processing means 2 incorporating a microprocessor 20, for example 8 bits, associated, via a communication bus, with a random access memory 21 and a read-only memory 22.
• Means control 3 are able to momentarily activate the receiving means and the processing means by respectively delivering to these two means corresponding control pulses.
• These control means can be incorporated in a conventional manner within the microprocessor 20, or can be produced by a specific conventional external circuit.
• control means are therefore able to put the receiver, either in an active state in which it is capable of receiving and processing the data contained in the carrier signal, or in a state of rest.
• the entire receiver is supplied by supply means 4 comprising a battery element associated with a DC-DC converter used to raise the voltage of this battery element to that necessary for the operation of the microprocessor.
• supply means 4 comprising a battery element associated with a DC-DC converter used to raise the voltage of this battery element to that necessary for the operation of the microprocessor.
• the read-only memory of the receiver is stored an indication of network IDRR, an indication of group IDG corresponding to a rank of packet in said frame, an indication of subgroup IDSG corresponding to the subgroup to which the receiver belongs, as well as the The receiver's actual ADD address.
• the transmission station ST essentially comprises MIS insertion means, produced for example in software within a PC-type microcomputer and receiving, for example, for a designated receiver on the one hand, its ADD address, its IDG group, IDSG subgroup and IDRR network indication, and, on the other hand, the data relating to the MMS message itself intended for it.
• MIS insertion means then generate the headers and the useful parts DU of the various elementary blocks which will constitute the packets, and in particular those relating to the blocks of identification of packets, network signaling, and message signaling.
• the operation of the transmission system according to the invention is briefly illustrated in the flow diagram of FIG. 7. After switching on the receiver, it will be placed in an acquisition phase 70 preceding a time synchronization phase 71. In phase 70, the receiver reception means
• RC will first of all wedge on one of the transmission channels and the processing means will test on the one hand the presence on this transmission channel of a subcarrier carrying the specific transmission protocol, this is that is to say in this case the SWIFT protocol, and, on the other hand, the presence in this protocol of a network signaling block containing a network identifier NWD corresponding to the network indication IDRR stored in the memory of the receiver (step 700 and 701).
• test duration Tm equal to the predetermined maximum duration of separation of two consecutive network signaling blocks, in this case 0.5 seconds
• the receiving means of the receiver will then search for another transmission channel (step 703) to carry out a new test until you get a positive result for it.
• the receiver if after a predetermined period of time, for example one minute, the receiver still does not find suitable transmission channels, it automatically goes into the rest state.
• the receiver processing means will then analyze the rank identifier IR contained in the next BLTS packet identification block.
• the receiver control means can maintain the latter in its active state after the analysis of the content of the network signaling block.
• each BLNS network signaling block an indication BN of the rank of this block in the packet which contains it (FIG. 2).
• the latter's control means can put the receiver in its resting state after analysis of the content of this BLNS network signaling block, until reception of the next block.
• BLTS packet identification When this BLTS block is acquired (step 704), the processing means analyze the content of this BLTS block, and in particular analyze the rank identifier IR which it contains.
• the receiver control means will then automatically time synchronize the passages of the receiver in its active state at successive instants separated from the initial instant of BLTS block acquisition of an integer multiple of the frame duration.
• the receiver control means will then put the latter in its idle state and then determine the occurrence of the BLTS identification block whose rank corresponds to the receiver group and then automatically synchronize the alarm clocks of the receiver from this moment, taking into account the duration of the frames.
• the time synchronization of the successive awakenings of the receiver is then performed (step 71).
• all the receivers of the same group will therefore wake up, that is to say go into their active state, at each instant of reception of the packet comprising at the head the BLTS packet identification block. whose IR rank indication corresponds to their group.
• all the receivers in the group will also analyze the content of the word MSF contained in the BLTS packet identification block, to find out which subgroups are likely to receive a message. .
• the control means place in their rest state, all the receivers whose subgroup indications IDSG do not match the subgroups designated in the word MSF.
• all the receivers of a subgroup which woke up at the start of the corresponding packet, can go into their rest state before the end of the transmission of said packet if all the messages have been acquired. This being the case, it is possible that at least some of the receivers remain active even after the end of transmission of their packet.
• the control means of all the receivers of the group force them to remain awake until the reception of the next signaling block of BLTS network, including those which were not designated in the word of subgroup MSF.
• the reception means can for example lock onto another channel.
• TT consists of three packets each having the duration TP.
• the packets are numbered from 0 to 2.
• the receiver RC11 has been programmed in the factory so as to belong to subgroup 1 of group No. 1.
• the reference BLTSO designates the identification block for packets of rank 0.
• the BLTS2 reference designates the rank 2 packet identification blocks.
• the BLTS 10 reference designates a rank 1 packet identification block designating for example furthermore only the subgroup 0 while the BLTS 11 reference designates a block d identification of rank 1 packets further designating subgroup 1.
• the receiver RC11 goes into its active state during the occurrence of the BLTS block 10, which designates the group 1 to which the receiver belongs but that the latter returns to its rest state after analysis of the content of this block because subfamily 1 is not designated therein.
• the receiver RC11 returns to its active state upon reception of the BLTS block 11 and remains awake after analysis of this block since the subgroup 1 is designated.
• the receiver remains awake until reception of the BLMS message signaling block, in which, in this case, the time indication DFS indicates that a BLDD message is intended for the receiver RC11 and that this message intervenes in the current packet, a well-defined moment.
• the receiver RC11 returns to the idle state until the occurrence of the first elementary data block, of the BLC type, of the BLDD message.
• the reference BLTS20 designates the packet identification block of rank 2 further designating the subgroup 0.
• the reference BLTSO 1 designates the packet identification block corresponding to group 0 and to subgroup 1 In this figure 9, it is assumed that the time indication
• DFS of the BLMS block indicates that the message intended for the RC11 receiver is not transmitted in the same packet as this BLMS block but is transmitted in a subsequent packet.
• the receiver RC11 returns to its rest state after the analysis of the BLMS block and will then wake up at each subsequent occurrence of a block package identification even if it does not correspond to its group.
• the receiver after analysis of this packet identification block, will remain awake if this block also contains an indication in the word MSF designating its subgroup. On the other hand, the receiver will go back to sleep if this identification block does not include a designation of its subgroup as is the case for the BLTS20 block (group 2 but subgroup 0).
• the RC11 receiver wakes up and analyzes the BLTSO 1 identification block (group 0 subgroup 1) and remains awake until the analysis of the message signaling block
• the receiver RC1 1 goes back to sleep until the reception of the BLDD message. After receiving this message, the sleep and wake-up cycles resume their usual rhythm.

Landscapes

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

Applications Claiming Priority (3)

Publications (1)

Family

ID=9511185

Family Applications (1)

Country Status (6)

Family Cites Families (1)

• 1997
  • 1997-09-17 FR FR9711587A patent/FR2768582B1/fr not_active Expired - Fee Related
• 1998
  • 1998-09-16 JP JP2000512363A patent/JP2001517042A/ja not_active Withdrawn
  • 1998-09-16 CA CA002302824A patent/CA2302824A1/fr not_active Abandoned
  • 1998-09-16 EP EP98943991A patent/EP1016290A1/fr not_active Withdrawn
  • 1998-09-16 WO PCT/FR1998/001972 patent/WO1999014957A1/fr not_active Application Discontinuation
  • 1998-09-17 TW TW87115625A patent/TW425825B/zh not_active IP Right Cessation

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events