Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L5/00—Arrangements affording multiple use of the transmission path
  • H04L5/003—Arrangements for allocating sub-channels of the transmission path
  • H04L5/0032—Distributed allocation, i.e. involving a plurality of allocating devices, each making partial allocation
  • H04L5/0035—Resource allocation in a cooperative multipoint environment
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L27/00—Modulated-carrier systems
  • H04L27/26—Systems using multi-frequency codes
  • H04L27/2601—Multicarrier modulation systems
  • H04L27/2626—Arrangements specific to the transmitter only
  • H04L27/2646—Arrangements specific to the transmitter only using feedback from receiver for adjusting OFDM transmission parameters, e.g. transmission timing or guard interval length
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L5/00—Arrangements affording multiple use of the transmission path
  • H04L5/003—Arrangements for allocating sub-channels of the transmission path
  • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04W—WIRELESS COMMUNICATION NETWORKS
  • H04W72/00—Local resource management
  • H04W72/20—Control channels or signalling for resource management
  • H04W72/21—Control channels or signalling for resource management in the uplink direction of a wireless link, i.e. towards the network

Definitions

• the invention relates to the general field of telecommunications.
• It relates more particularly to a method making it possible to optimize the transmission of data in uplink (or channel) from a terminal benefiting from dual connectivity (or “Dual Connectivity” in English) at radio level with a first device for accessing a first telecommunications network and with a second device for accessing a second telecommunications network (the first and second telecommunications networks may be identical or distinct), in a context where the terminal is only authorized to transmit data to a instant only to one of the two access devices.
• This mode of operation is also known as "Single Uplink Operation" (or SUO mode) in English.
• a terminal can be connected simultaneously to a so-called master node (or “Master Node”) and to a so-called secondary node (or “Secondary Node”), the master node and the secondary node not being co-located and being able to operate in distinct frequency bands.
• 5G Fifth Generation Partnership Program
• the master node is sometimes a device for accessing a LTE network (Long Term Evolution) of 4th generation (4G) or eNodeB, sometimes a device for accessing a NR 5G or gNB network, and the secondary node is a device for accessing gNB to a NR 5G network.
• 4G Long Term Evolution
• eNodeB Long Term Evolution-based NR 5G
• gNB NR 5G network
• Double connectivity is a mechanism which advantageously allows the aggregation of radio resources (and in particular the bit rates) offered by the master and secondary nodes.
• the version ("release") 15 of the 3GPP standard specifies that the terminal is not authorized at any given time to transmit of data only to one of the two nodes: the terminal is therefore forced, in accordance with the 3GPP standard, to operate in OUA mode when it has dual connectivity.
• the exchanges between the master and secondary nodes to allow this double connectivity in SUO mode have been standardized for EN-DC and NR NR DC and are carried out via the interfaces X2 and XN respectively.
• Each of the master and secondary nodes manages the traffic which passes through it autonomously at the level of its MAC layer (Medium Access Layer) and of its physical layer, and no information is exchanged between the MAC schedulers of the two nodes during this double connectivity. It is therefore not possible to count on any coordination between the MAC schedulers of the two nodes to implement the SUO mode.
• MAC layer Medium Access Layer
• the mechanism adopted by the 3GPP standard consists of coordination between the master node and the secondary node based on the exchange of a two-dimensional map (a frequency dimension and a time dimension), more commonly known as "bitmap", indicating for each of the nodes, the physical resource blocks or PRB (Physical Resource Block) and the sub-frames (corresponding to a granularity of 1 ms) that it occupies.
• PRB Physical Resource Block
• a PRB corresponds to the smallest frequency resource unit that can be allocated to a terminal: it occupies a bandwidth of 180 kHz, and a duration of 1 ms corresponding to a subframe.
• Each subframe includes one or more slots according to the numerology considered by the telecommunications network (for example, 1 Slot for a spacing between the sub-carriers of 15 kHz, which corresponds in LTE standard to the smallest transmission interval or TTI for Time Transmission Interval envisaged for the data channels), each Slot comprising 14 data symbols.
• Each sub-frame belongs to a frame with a duration of 10 ms, numbered by an SFN (for System Frame Number) number between 0 and 1023; each frame includes 10 subframes numbered from 0 to 9.
• Bitmap exchanges are performed at the PDCP (Packet Data Convergence Protocol) layer and are therefore slow and semi-static in nature. They allow the two nodes to agree on a time multiplexing pattern (or TDM for Time Division Multiplexing) to allow operation in SUO mode: this pattern provides a semi-static configuration (per cell or per terminal) shared in a mode particular with the terminal defining which subframes transmitted by the terminal are dedicated to the uplink to the master node and which subframes are dedicated to the uplink to the secondary node.
• PDCP Packet Data Convergence Protocol
• the synchronization aspects between the master and secondary nodes are important.
• the transmissions of the different subframes and frames sent on the uplinks to the master and secondary nodes may in fact not be aligned due to an asynchronism between the networks of the master and secondary nodes or to time advance values (or "Timing advance") different (intended to compensate for the propagation times between the master and secondary nodes and the terminal).
• This can have a direct impact on the time multiplexing pattern to be exchanged between the master and secondary nodes to ensure that the terminal does not simultaneously transmit data to the two nodes.
• the EN-DC scenario makes the assumption that the networks of the master and secondary nodes are synchronized (cf.
• FIG. 1 A solution that can be envisaged is illustrated in FIG. 1, in a context where a terminal UE has dual connectivity with a first node NODE1 and with a second node NODE2 via two uplinks UL1 and UL2 established respectively with these two nodes.
• each sub-frame belongs to a numbered frame.
• the time limits of the sub-frames transmitted on the uplinks UL1 and UL2 present in this example, a relative deviation referenced by "OFFSET", linked to the absence of synchronization between the two nodes NODE1 and NODE2.
• a solution can consist, as illustrated in FIG. 1, in defining and exchanging between the two nodes NODE1 and NODE2, for example on the interface X2, a time multiplexing pattern consisting in the bitmap sent by the NODE2 node to the NODE1 node, to reserve the X + 1 and X + 2 subframes for the uplink UL1 and, in the bitmap sent by the NODE1 node to the NODE2 node, to reserve the Y + subframes 3 and Y + 4 for the uplink UL2.
• the terminal UE does not transmit on the uplink UL2 (represented by hatching in FIG.
• the invention makes it possible to reduce this loss of spectral efficiency by proposing a method for managing a transmission of sequences of symbols of data of fixed duration by a terminal having dual connectivity established with a first device for accessing a network of telecommunications and with a second device for accessing a telecommunications network, said terminal being configured to transmit, during said double connectivity, sequences of data symbols on a first uplink channel to said first access device and on a second uplink to said second access device during disjoint time intervals, said method comprising:
• a step of configuring the terminal so that it introduces at least one guard interval during each transmission of at least one sequence of data symbols on said first uplink channel to the first access device, during which no symbol of data is not transmitted by said terminal on said first uplink, said at least one guard interval being introduced by the terminal at the start of a first sequence of data symbols and / or at the end of a last sequence of symbols of data transmitted during said transmission on said first uplink, and occupying a number of symbols determined as a function of the estimation of said difference between said propagation delays.
• the first and second access devices may or may not belong to the same telecommunications network. Furthermore, no limitation is attached to the telecommunications networks of the access devices. The invention however a preferred application when at least one of the networks is a 4G LTE network or a 5G NR network (and when at least one of the access devices is an eNodeB device or a gNB device).
• the invention thus proposes to introduce a guard interval at the start and / or at the end of each transmission of sequence (s) of contiguous data symbols intended for one of the two access devices chosen as reference (first access device within the meaning of the invention). It is noted that no limitation is attached to the duration or to the dimension of the sequences of data symbols considered, this being able to depend on the granularity envisaged on the network for transmitting the data. Thus a sequence of data symbols within the meaning of the invention can correspond to a subframe or to a slot for example.
• the guard interval (s) considered in the invention is (are) advantageously inserted in the first and / or in the last sequence of symbols (ie in replacement of the data symbols) and corresponds (s) to one (or more) time interval (s) during which the terminal does not transmit any data on the uplink with the reference access device. It (s) is (are) dimensioned so as to take into account the abovementioned synchronization aspects between the two access devices, and in particular the propagation delays between the terminal and the two access devices.
• the guard interval (s) is (are) dimensioned as a function of an estimated parameter by the terminal representative of a synchronization difference between the first and second access devices.
• the number of symbols of said at least one guard interval is in this embodiment determined as a function of the estimate of the difference in propagation times and of a synchronization difference estimated by the terminal.
• This synchronization difference can be estimated by the terminal from the synchronization signals sent by the two downlink access devices and received by the terminal.
• the loss of spectral efficiency resulting from the implementation of the invention corresponds to the dimension in number of data symbols of the guard interval (s) introduced. This dimension depends on the numerology adopted on the link of the first access device taken as a reference, but is, in any event, less than a sub-frame.
• the invention therefore provides a simple and effective solution for optimizing dual connectivity in SUO mode.
• the obtaining step comprises obtaining:
• a second value maximizing, for positions of the terminal included in a geographical area covered simultaneously by the first and second access devices and such that the propagation delay between the terminal and the first access device is greater than the propagation delay between the terminal and the second access device, a difference between the propagation delay between the terminal and the first access device and the propagation delay between the terminal and the second access device.
• the terminal is configured to introduce a first guard interval at the end of the last sequence of data symbols occupying a number of symbols determined as a function of the first value, and / or a second guard interval at the start of the first sequence of data symbols occupying a number of symbols determined as a function of the second value.
• the first value and the second value can be determined by test and / or by simulation, for example using hedging tools known per se, or by performing field measurements.
• the advantage of this first variant is that it frees itself from knowing the position of the terminal and, where appropriate, its mobility: the dimensioning of the guard intervals is carried out on the basis of values which are calculated to take account of the delays of the highest propagation likely to exist between the terminal and the first and second access devices taking into account the configuration of the area covered by the two access devices.
• the first value obtained relates to the scenario where the terminal is in a coverage area common to the two access devices but is closer to the first access device;
• the second value obtained targets the case where the terminal is in a coverage area common to the two access devices but is closer to the second access device.
• one or the other of these two values is zero (for example when due to the configuration envisaged the terminal is brought to be in a common coverage area very far from one of the access devices). In this case, this is equivalent to applying only one guard interval, either at the start or at the end of each transmission on the first uplink, depending on the value which is not zero.
• the terminal is configured to introduce a single guard interval at the start of the first sequence or at the end of the last sequence and the management method according to the invention comprises: - a step of estimating said deviation by the terminal from time advance values associated with the first access device and the second access device and supplied to the terminal by the first access device and by the second access device respectively, said unique number of symbols and the introduction of the guard interval at the start of the first sequence or at the end of the last sequence being determined by the terminal as a function of said estimated deviation and of a geographical position of the terminal with respect to the first and second device access; and
• This second variant consists of the introduction of a single guard interval, the position and sizing of which are optimized with respect to the effective location of the terminal. This second variant makes it possible to further reduce the loss of spectral efficiency.
• the terminal itself which determines the number of symbols over which the guard interval must extend, on the basis of the time advance values which it has received from the first and second which reflect, as mentioned above, the propagation times between the terminal and the first and second access devices.
• time advance values are conventionally shared over networks by access devices with the terminals attached to them in order to be applied in an uplink.
• the terminal goes back directly to the first access device the number of symbols occupied by the guard interval to be applied: this number of symbols being already quantified, this makes it possible to limit the signaling exchanged between the terminal and the first access device.
• the rise by the terminal of the number of symbols of the guard interval towards the first access device allows the latter to ensure the orchestration of data transmissions on the network, in accordance with the operating mode of current networks (ie it is the network which organizes data transmissions).
• the management method further comprises:
• This embodiment has a particular advantage in an asynchronous context in which the access devices belong to separate telecommunications networks which are not synchronized with one another.
• the access devices belong to separate telecommunications networks which are not synchronized with one another.
• the terminal thanks to the synchronization signals it receives from the first and second devices, is able to estimate the asynchronism between the two access devices between the received sequence numbers represented by the integer NO.
• This number is communicated to the first access device so that it can take it into account when exchanging bitmaps with the second access device. It should be noted that this number does not need to be communicated by the first access device to the second access device: it is sufficient that only the first access device takes it into account during the exchange. bitmaps to decide which sequences of data symbols are transmitted on the first uplink and which sequences of data symbols are transmitted on the second uplink. The second access device continues to consider that the first access device is synchronous with it, in other words the asynchronism present between the two access devices remains transparent to the second access device.
• the invention proposes the introduction of one or more guard intervals into the sequences of data symbols transmitted on the uplink established during double connectivity with one of the access devices chosen as the reference node (first access device within the meaning of the invention).
• This introduction is transparent to the other access device.
• the implementation of the invention therefore relies more particularly on two entities, namely on the terminal and on the first access device, and also relates to the methods implemented by these entities to support the invention.
• the invention also relates to a method of transmitting sequences of data symbols by a terminal having dual connectivity established with a first device for accessing a telecommunications network and with a second device for accessing a telecommunications network.
• said terminal being configured to transmit, via said dual connectivity, sequences of data symbols to said first access device on a first uplink and to said second access device on a second uplink during disjoint time intervals, this method being intended to be implemented by the terminal and comprising
• a step of reception from the first access device of a message comprising at least a number of symbols of at least one guard interval to be introduced during each transmission of sequences of data symbols by the terminal on the first uplink to the first access device, said at least a number of symbols having been determined as a function of an estimate of a difference between propagation delays between the terminal and the first access device and between the terminal and the second access device;
• the invention also relates to a terminal having a double connectivity established with a first device for accessing a telecommunications network and with a second device for accessing a telecommunications network, said terminal comprising a transmission module configured to transmit , via said dual connectivity, sequences of data symbols on a first uplink to said first access device and on a second uplink to said second access device during disjoint time intervals, said terminal further comprising
• a reception module capable of receiving from the first access device a message comprising at least a number of symbols of at least one guard interval to be introduced during each transmission of sequences of data symbols by the terminal on said first uplink to the first access device, said at least a number of symbols having been determined as a function of an estimate of a difference between propagation delays between the terminal and the first access device and between the terminal and the second access device;
• an insertion module activated during each transmission of sequences of data symbols by the terminal on said first uplink, and configured to introduce said at least one guard interval at the start of a first sequence of data symbols and / or at the end of a last sequence of data symbols transmitted during said transmission on said first uplink according to a setpoint included in the message.
• the instruction included in the message can take different forms. It can in particular, in the example of a single guard interval, take the form of a bit having the value 0 if the guard interval must be introduced at the start of the first sequence or the value 1 if the interval guard must be entered at the end of the last sequence.
• the number or numbers of symbols included in the message can be signed, and for example have a positive value for a number of symbols corresponding to a guard interval inserted at the start of the first sequence and a negative value for a number of symbols corresponding to a guard interval inserted at the end of the last sequence.
• these examples are only given by way of illustration and other alternative embodiments can be envisaged.
• a step of estimating said deviation by the terminal from time advance values associated with the first access device and the second device access and provided to the terminal by the first access device and by the second access device respectively, said unique number of symbols and the introduction of the guard interval at the start of the first sequence or at the end of the last sequence being determined by the terminal as a function of said estimated deviation and of a geographical position of the terminal with respect to the first and second access device;
• the indication that the guard interval must be entered at the start of the first sequence or at the end of the last sequence may in particular be provided by the terminal to the first access device (it may in particular take a form similar to the instruction entered in the message transmitted to the terminal).
• the sequences of data symbols transmitted by the terminal on the first and second uplink channels are numbered and included in numbered frames, said transmission method further comprising a step of estimating a deviation of synchronization between the first and second access devices from synchronization signals received from the first and second access devices, this estimation step comprising
• T0 denotes said determined duration of the sequences of data symbols, the number NO and the offset parameter being representative of said synchronization difference between the first and second access devices; and said at least one number of symbols being determined in addition to said offset parameter determined by the terminal.
• the terminal also comprises a second module for estimating a synchronization difference between the first and second access devices, said second estimation module being configured for:
• T / V0.T0 + offset
• T0 designates said determined duration of the sequences of data symbols, the number NO and the offset parameter being representative of said synchronization difference between the first and second access devices; and said at least one number of symbols being determined in addition to said offset parameter determined by the terminal.
• This embodiment makes it possible to take into account, in addition to the propagation delays, for dimensioning the guard interval or intervals of asynchronism that may exist between the access devices, this asynchronism being represented by the number NO and by the offset parameter.
• the transmission method further comprises a step of supplying said offset parameter by the terminal to the first device. access.
• the transmission method further comprises a step of supplying the number NO to the first access device for using it during an exchange of bitmaps with the second access device intended to organize the transmission. sequences of data symbols by the terminal on the first and second uplink channels during said dual connectivity.
• the terminal comprises in this embodiment a second supply module configured to supply the number N0 to the first access device for use during a bitmap exchange with the second access device intended to organize the transmission. sequences of data symbols by the terminal on the first and second uplink channels during said dual connectivity.
• the invention also relates to a device for accessing a telecommunications network, called the first access device, capable of managing a transmission of sequences of data symbol sequences of predetermined duration by a terminal having dual connectivity established with said first.
• a device for accessing a telecommunications network and with a second device for accessing a telecommunications network said terminal being configured to transmit during said dual connectivity of data symbol sequences on a first uplink to said first access device and on a second uplink to said second access device during disjoint time intervals, said first access device comprising
• a obtaining module capable of obtaining an estimate of a difference between propagation times between the terminal and the first access device and between the terminal and the second access device;
• a configuration module configured to configure the terminal so that it introduces at least one guard interval during each transmission of at least one sequence of data symbols on said first uplink channel to the first access device, during which no data symbol is transmitted by said terminal on said first uplink, said at least one guard interval being introduced by the terminal at the start of a first sequence of data symbols and / or at the end of a last sequence of data symbols transmitted during said transmission on said first uplink, and occupying a number of symbols determined as a function of the estimation of said difference between said propagation delays.
• the configuration module is configured to send to the terminal a message comprising the number of symbols occupied by each guard interval and an instruction indicating whether said at least one guard interval must be entered at the start of the first sequence of data symbols and / or at the end of the last sequence.
• the first access device according to the invention benefits from the same advantages described above as the management method.
• the different steps of the management method and / or the different steps of the transmission method are determined by instructions from computer programs.
• the invention also relates to a computer program on an information medium, this program being capable of being implemented in a device for accessing a telecommunications network, respectively in a terminal, or more generally in a computer, this program with instructions adapted to the implementation of the steps of a management method, respectively of a transmission method as described above.
• This program can use any programming language, and be in the form of source code, object code, or intermediate code between source code and object code, such as in a partially compiled form, or in any other desirable form.
• the invention also relates to an information or recording medium readable by a computer, and comprising instructions of a computer program as mentioned above.
• the information or recording medium can be any entity or device capable of storing the program.
• the support may include a storage means, such as a ROM, for example a CD ROM or a microelectronic circuit ROM, or else a magnetic recording means, for example a floppy disk or a disc. hard.
• the information or recording medium can be a transmissible medium such as an electrical or optical signal, which can be routed via an electrical or optical cable, by radio or by other means.
• the program according to the invention can in particular be downloaded from a network of the Internet type.
• the information or recording medium can be an integrated circuit in which the program is incorporated, the circuit being adapted to execute or to be used in the execution of the process in question.
• the invention also relates to a communication system comprising:
• the first access device is in accordance with the invention.
• the invention has a preferred application when these networks are LTE 4G and / or N R 5G networks.
• the first access device uses a larger numerology than the second access device.
• numerology refers to the spacing between the subcarriers of the waveform used to transmit data symbols over the network.
• the spacing between the subcarriers is inversely proportional to the symbol time so that the larger the numerology, the more the symbol time is reduced.
• the first and second access devices can then be configured to exchange bitmaps with each other corresponding to the smallest numerology intended to organize the transmission of the sequences of data symbols by the terminal over the first and second uplink channels during said dual connectivity.
• FIG 2 shows a communication system according to the invention
• FIG 3 shows the hardware architecture of a computer on which the entities of the communication system of Figure 2 are based;
• Figure 4 shows the main functional modules of an access device according to the invention, in a first embodiment
• Figure 5 shows the main functional modules of a terminal according to the invention, in the first embodiment
• FIG 6 shows, in the form of a flowchart, the main steps of the management method according to the invention implemented by the access device of Figure 4 in the first embodiment;
• FIG 7 shows, in the form of a flowchart, the main steps of the transmission method according to the invention implemented by the terminal of Figure 5 in the first embodiment
• Figure 8A represents a case considered in the first embodiment to estimate the difference between the propagation delays used to size the guard intervals in the first embodiment
• FIG. 8B represents a second case considered in the first embodiment for estimating the difference between the propagation delays used to size the guard intervals in the first embodiment;
• Figure 9 illustrates the consequences of the introduction of one or two guard intervals in the first embodiment on the transmissions operated on the two uplink channels maintained by the terminal of Figure 5;
• Figure 10 shows the main functional modules of a terminal according to the invention, in a second embodiment
• Figure 1 1 shows, in the form of a flowchart, the main steps of the transmission method according to the invention implemented by terminal in the second embodiment;
• Figure 12 shows, in the form of a flowchart, the main steps of the management method implemented by the reference access device in the second embodiment.
• FIG. 2 represents, in its environment, a communication system 1 according to the invention, in a particular embodiment.
• the communication system 1 advantageously offers the possibility for a terminal to benefit from dual connectivity (“dual connectivity”) with two devices for accessing telecommunications networks in “Single Uplink Operation” or OUA mode.
• the communication system 1 includes for this purpose
• the terminal 4 is for example a mobile terminal such as a smart phone, or a digital tablet, or a laptop, etc.
• the telecommunications network 2 is an LTE 4G network and the telecommunications network 3 is an NR 5G network: in other words, the access device MN is a node of the eNodeB type and the device SN is a gNB type node. It is assumed here that the access devices MN and SN are not co-located and that the networks 2 and 3 are not synchronized. It is considered in this configuration, that for the implementation of dual connectivity, the access device MN is the master node while the access device SN is the secondary node. This makes it possible to rely on the LTE core network of the MN access device during dual connectivity.
• networks 2 and 3 can be one and the same network, or both be 5G networks
• the master node can be the device for accessing the 5G network
• the secondary node can be the device for accessing the 4G network.
• networks 2 and 3 can be synchronized, etc.
• the double connectivity results in the establishment by the terminal 4 of two radio supports, that is to say two uplink channels UL1 and UL2, with the access device MN respectively and with the device SN access (and correspondingly by establishing two downlink DL1 and DL2 with the MN and SN access devices respectively).
• the two access devices MN and SN have an interface X2 as defined in the 3GPP standard and described in particular in the document 3GPP TS 36.423 V15.2.0 (2018-06), this interface allowing them to exchange various information during dual connectivity, and in particular the bitmaps applied by terminal 4 on the uplinks UL1 and UL2.
• bitmaps define a two-dimensional mapping indicating which subframes and which physical resource blocks (or PRB) are dedicated to the uplink UL1 and which subframes and which physical resource blocks (or PRB) are dedicated to uplink UL2.
• the format of the information contained in the bitmaps is described in the document 3GPP TS 36.423 v15.2.0 Release 15, June 2018, in sections 9.2.1 16 and 9.2.1 17.
• the communication system 1 offers improved management of the uplink transmissions of the terminal 4 when the latter benefits dual connectivity in OUA mode.
• This improved management is enabled, in accordance with the invention, by the introduction of guard interval (s) judiciously sized (s) in the transmissions carried out on the uplink established with one of the two access devices which plays the role of reference node.
• guard interval means here a time interval during which the terminal transmits no data on the reference uplink although the negotiation of the bitmaps between the two access devices has led to assigning this time interval to the device d 'reference access.
• each uplink transmission consists of the sending by the terminal 4 of one or more numbered sub-frames with a determined duration of 1 ms each (each sub-frame carrying a number between 0 and 9 ), each sub-frame belonging to a numbered frame with a duration of 10 ms (each frame carrying a number or SFN between 0 and 1023).
• Each subframe carries a plurality of symbols and constitutes a sequence of data symbols within the meaning of the invention.
• the dimensioning of the guard interval (s) is advantageously carried out according to the invention as a function in particular of the propagation times existing between the terminal 4 and the access devices MN and SN. In the embodiments described here, it also takes into account an asynchrony between the access devices MN and SN.
• the dimensioning of the guard interval or intervals is carried out by the node reference, that is to say by the access device SN (first access device within the meaning of the invention).
• the secondary access device SN is in accordance with the invention.
• the dimensioning of the guard interval or intervals is carried out by the terminal 4.
• the access device MN, the access device SN and the terminal 4 have the hardware architecture of a computer 5, as shown diagrammatically in FIG. 3.
• a processor 6 includes in particular a processor 6, a random access memory 7, a read-only memory 8, a non-volatile flash memory 9, as well as communication means 10 comprising one or more communication interfaces.
• the communication means 10 of the terminal 4 and of the access device MN, respectively of the access device SN, allow them to communicate with each other via the telecommunications network 2 and in particular via the uplink UL1 and downlink DL1, respectively via the telecommunications network 3 and in particular via the uplink UL2 and downlink DL2 (see Figure 2).
• the read-only memory 8 of the access device SN constitutes a recording medium according to the invention, readable by the processor 6 and on which are recorded a computer program PROGSN-1 according to the invention, comprising instructions for the execution of the steps of the management method according to the invention corresponding to the first embodiment.
• This PROGSN-1 computer program defines, as illustrated in FIG. 4, functional modules (and software here) of the access device SN, which are configured to implement the steps of the management method according to the invention and which are based on and / or control the hardware elements 6-10 of the computer 5 cited above. These modules include here
• a obtaining module 11 capable of obtaining an estimate of a difference between the propagation times between the terminal 4 and the access device MN and between the terminal 4 and the access device SN;
• the terminal 4 also includes a supply module 20 of the number N0 and of the offset parameter representative of the synchronization difference between the two access devices MN and SN to the access device SN.
• 01 (0) max (PD (4, MN) -PD (4, SN)) with PD (4, MN)> PD (4, SN)
• O2 (0) max (PD (4, SN) -PD (4, MN)) with PD (4, SN)> PD (4, MN)
• the terminal 4 following the reception of the synchronization signals from the access devices MN and SN (step F10), the terminal 4, via its estimation module 19, measures from synchronization signals the time difference noted T between the time limits of the frames transmitted on the two downlink DL1 and DL2 and carrying the same SFN number (step F20).
• the estimation module 19 of the terminal 4 determines, from the time difference T thus measured, the offset parameter as well as the integer NO (step F30). More particularly, the time difference T is defined as follows
• the offset parameter is a relative number. Its sign is determined with respect to the reference uplink, namely UL2 in the example considered: thus, the offset parameter is chosen positive if the time limit of the sub-frames of the reference channel UL2 is after the time limit sub-frames sent on the other channel (UL1 here) (see situation illustrated in Figure 1), and is chosen negative otherwise.
• the dimension of the guard interval GP1 is determined by the determination module 12 as a function of the value 01, in other words as a function of the value of 01 (0) and of the offset parameter.
• offset 0 and the dimension of the guard interval GP1 is determined from 01 (0) directly
• the dimensions d1 and d2 of the guard intervals GP1 and GP2 are determined by the determination module 12 of the access device SN in number of symbols (OFDM symbols in the case of a 4G or 5G network). This number of symbols depends on the numerology used on the uplink reference UL2. As examples, suppose that only the value 01 is non-zero and equal to 6.67.10-5. The result
• V POS F represents how the transmissions are organized in G example considered on the uplink UL1 associated with the MN access device, when any shift (but lower or worst case shift 01 ) exists between the time limits of the sub-frames on the uplink UL1 and the time limits of the sub-frames on the reference uplink UL2, in the positive qualified direction;
• UL2 (SN) the line referenced by "UL2 (SN)" represents how the transmissions are organized in the example considered on the uplink reference UL2 associated with the access device SN, with the insertion in the illustrated example of intervals of guard GP1 and GP2 (resulting equivalently in a single guard interval GP of dimension d1 + d2).
• NO TX (UL2) means that no transmission is performed on the uplink UL2 while “TX (UL2)” means that sub-frames of data symbols are transmitted by the terminal 4 on the UL2 channel.
• Guard intervals are inserted in accordance with the invention in the part reserved for transmissions on the uplink UL2.
• the computer program PROG4-2 defines, as illustrated in FIG. 10, functional modules (and software here) of the terminal 4, which are configured to implement the steps of the transmission method according to the invention and which are press and / or control the hardware elements 6-10 of the computer 5 mentioned above. These modules include
• the PROG4-2 program also defines three other functional modules of terminal 4, namely
• an estimation module 26 configured to estimate the difference between the propagation delays PD (4, SN) and PD (4, MN) from time advance values associated with the access devices SN and MN and supplied to terminal 4 by the access devices SN and MN;
• Terminal 4 is assumed to have dual connectivity established with the MN and SN access devices via the UL1 / DL1 and UL2 / DL2 channels.
• a single guard interval is provided and its positioning in the transmission on the uplink UL2 depends on the geographic position of the terminal 4 relative to the access devices SN and MN (ie according to s '' it is closer to the access device SN, and therefore to the propagation time PD (4, SN) ⁇ PD (4, MN), or to the access device MN and to the propagation time PD (4, MN) ⁇ PD (4, SN)).
• the estimation module 24 of the terminal 4 also determines the number NO that it transmits to the reference access device SN (step G25).
• the terminal 4 determines where the guard interval GP must be inserted during its transmissions on the uplink of reference UL2 as well as its dimension (step G40). More specifically
• the guard interval GP is introduced at the end of each transmission from terminal 4 on the uplink UL2, in the last data symbol sub-frame transmitted during this transmission;
• the access device SN undertakes an exchange with the access device MN on the interface X2 in order to organize the transmission of the sub-frames of data symbols by the terminal 4 on the uplinks UL1 and UL2 during double connectivity (step H30). This exchange takes place in an identical manner to what was described for the first embodiment for step E50.
• the negotiated bitmaps are transmitted in a particular mode by each of the access devices to the terminal 4 to be applied on the uplinks UL1 and UL2 (step H40).
• the terminal 4 then sends the sub-frames of data symbols intended for the access devices MN and SN by introducing (inserting) via its module d insertion 23, in accordance with the invention and the configuration indicated in the message MESS received from the access device SN (step G60), a guard interval GP in each transmission of one or more sub-frames carried out on the uplink reference UL2 (step G70).
• the guard interval GP occupying d data symbols is inserted at the end of the last sub-frame sent during the transmission if the terminal 4 is closer to the access device SN and at the start of the first sub-frame sent otherwise during this transmission.
• the secondary access device SN participating in the double connectivity has been chosen as the reference access device.
• This assumption is not limiting in itself, and in a variant other criteria can be applied to select the reference access device (first access device within the meaning of the invention).
• the reference access device chosen may be the one that uses the largest numerology between the two access devices MN and SN.
• bits E50 and H30 for exchanging bitmaps between the two access devices MN and SN.
• these bitmaps are produced on the basis of the most numerology small used by the two access devices MN and SN, and / or that the number of symbols of the guard interval or intervals to be inserted is determined according to this largest numerology. In this way, we get a better granularity and a minimum loss of spectral efficiency linked to the introduction of the guard interval (s).

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• 2018
  • 2018-12-11 FR FR1872687A patent/FR3089733A1/fr active Pending
• 2019
  • 2019-11-29 US US17/312,877 patent/US11924123B2/en active Active
  • 2019-11-29 WO PCT/FR2019/052841 patent/WO2020120861A1/fr unknown
  • 2019-11-29 EP EP19835701.4A patent/EP3895358A1/fr active Pending
  • 2019-11-29 CN CN201980089659.XA patent/CN113439407B/zh active Active

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