A communication method for an NTN network

Abstract

A COMMUNICATION METHOD FOR AN NTN NETWORK Invention is a communication method realized by a system comprising a non-terrestrial network node (100) and plurality of user equipment.

Description

[0001] DESCRIPTION

[0002] A COMMUNICATION METHOD FOR AN NTN NETWORK

[0003] TECHNICAL FIELD

[0004] Invention relates to a communication method realized by a system comprising a non-terrestrial network node and plurality of user equipment.

[0005] PRIOR ART loT devices often send their data or status updates to base stations (or via relay) at different intervals. These communications, as seen by an intended receiver (BS or relay), involve a large number of connections while each packet carries a variable amount of data, and the transmission timing is either periodic or predictable. However, the existing design principles of communication networks do not align well with these specific needs of loT scenarios. Currently, the radio access section of cellular networks is optimized for a limited number of connections, each with significant data needs. This framework places a high emphasis on the control signaling which may be unnecessarily heavy for some operations. For instance a 32- bit sensor reading can be given. Data volume due to control signalling is way more than payload.

[0006] Resource schedulers for available resources are designed so that resources are allocated on a user-by-user basis; This consumes a lot of resources, especially for loT devices. For example, a UE-specific control signal is designed to schedule a UE in all cases.

[0007] Further, relay consume increased amount of energy in a network is due to the continuous monitoring for uplink transmission activity (i.e. LoRa) on its channel. In non-terrestrial networks, energy is not provided from the grid, thus it may be limited due to usage of batteries.

[0008] All the problems mentioned above have made it necessary to make an innovation in the relevant technical field as a result. BRIEF DESCRIPTION OF THE INVENTION

[0009] The present invention relates to a method to eliminate the above-mentioned disadvantages and bring new advantages to the relevant technical field.

[0010] An object of the invention is to provide a communication method which reduces control signaling.

[0011] An object of the invention is to provide a communication method which reduces power consumption of network nodes.

[0012] To achieve all the objects mentioned above and that will emerge from the following detailed description, the present invention relates to a communication method realized by a system comprising a non-terrestrial network node and plurality of user equipment. Accordingly, comprising steps of;

[0013] - by the network node, accessing a transmit pattern vector comprising indicators whether the UE will transmit data or not in predetermined time frames,

[0014] - determining overloading user equipment that will transmit data on overloaded time frames;

[0015] - selecting at least one overloading user equipment;

[0016] - determining available time frames where the number of expected transmissions is less than the number of available transmission slots;

[0017] - assigning selected at least one overloading equipment’s at least one overloaded transmission to one of the determined available time frames and transmitting updated transmit pattern vector to the user equipment;

[0018] - by user equipment, transmitting data based on the transmit pattern vector. Thus, control signaling is significantly reduced.

[0019] A possible embodiment of the invention is characterized in that the network node is a relay comprising a transceiver and a processor for processing received signal from transceiver; and the method comprises the steps of;

[0020] - by the network node, operating in an operating mode where the transceiver listens the channel during the time frames where there is expected transmission and operating in an energy saving mode during the time frames where there is no expected transmission. Thus, energy consumption of the relay is significantly reduced. Another possible embodiment of the invention is characterized in that the overloading user equipment are selected based on a predetermined priority list.

[0021] Another possible embodiment of the invention is characterized in that comprising the steps of;

[0022] - in operating mode processor is in sleep mode and if a transmission is received during the operating mode, activating the processor for processing received transmission.

[0023] Another possible embodiment of the invention is characterized in that the transmit pattern vector comprising indicators relating to a priority degree of the user equipment.

[0024] Another possible embodiment of the invention is characterized in that comprising the step of; by the plurality of user equipment, transmitting a transmit pattern vector comprising indicators whether the UE will transmit data or not in predetermined time frames.

[0025] Another possible embodiment of the invention is characterized in that comprising the step of; by the network node, monitoring transmit patterns of user equipment and generating a transmit pattern vector comprising indicators whether the UE will transmit data or not in predetermined time frames.

[0026] Another possible embodiment of the invention is characterized in that comprising the steps of;

[0027] - in energy saving mode network node turns itself on for a predetermined time window for receiving spontaneous uplink request wherein the said predetermined time window is shorter than a single time frame;

[0028] - if no signal is received during the predetermined time window switching to sleep mode where it can be activated with a wake up signal;

[0029] - if a spontaneous uplink request is received, activating processor to realize the uplink request and waits for an inactivity time window until switching to sleeping mode. This embodiment provides a method that reduces energy consumption while providing service to spontaneous uplink requests.

[0030] The invention is also a system comprising a network node and a user equipment. Accordingly, the system is configured to realize one of the methods of one of the claims 1 -5.

[0031] BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a drawing illustrating schematic view of the system that realizes the subject matter method.

[0032] Figure 2 is a drawing illustrating schematic view of one embodiment of the system that realizes the subject matter method.

[0033] Figure 3 is a drawing illustrating transmission frame.

[0034] REFERENCE NUMBERS GIVEN IN THE FIGURE

[0035] 100 Network node

[0036] 200 User equipment

[0037] 300 Transmission frame

[0038] SS control signal slots

[0039] UL Uplink slots

[0040] DL Downlink slots

[0041] 310 Transmission slot

[0042] RA Random access slot

[0043] DETAILED DESCRIPTION OF THE INVENTION

[0044] In this detailed description, the subject matter is explained with references to examples without forming any restrictive effect only in order to make the subject more understandable.

[0045] Referring to figure 1 , invention is a method realized by a system comprising at least one nonterrestrial network node (100) and plurality of user equipment (200). User equipment (200) are equipped with transceiver means (not shown) for transmitting signal to network node (100) and receive signal from the network node (100) and processing means for controlling the transmission and processing the received signals.

[0046] User equipment (200) stores instructions to be executed by processing means for realizing the steps of the subject matter method. Network node (100) also stores instructions to be executed. User equipment (200) may be an loT device, smart phone, computer etc. Network node (100) may be a base station, access point, a network relay of a non-terrestrial network. Technical details of such user equipment (200) and network nodes (100) are well known in the art, thus further technical details are not disclosed herein. In a first embodiment of the subject matter method, user equipment (200) accesses to a transmit pattern vector, which comprises indicators whether the user equipment (200) will transmit data or not in predetermined transmission frames (300). User equipment (200) may generate transmit pattern vectors based on the time data and its transmission schedule or access it from a data storage means.

[0047] Referring to figure 3, transmission frames (300) are defined as time frames arranged in a time axis. Each transmission frame (300) comprises slots for data transmission. For example each frame may comprise control signal slots (SS) dedicated for control signaling, uplink slots (UL) dedicated for uplink transmission, downlink slots (DL) dedicated for downlink transmission. In this embodiment, each frame comprises at least one uplink slot. Each uplink slot comprises transmission slots (310) each can be used to transmit data of one user equipment (200). Uplink slots (UL) may comprise random access slots (RA) for meet the random access needs. Number of available transmission slots (310) are predetermined for each transmission frame (300).

[0048] Transmit pattern vector may be as below equation; where i stands for the ID of user equipment (200) and k is the ID of transmission frame (300). An exemplary transmit pattern vector may be as follows for a user equipment (200) having ID as 1.

[0049] P1 =[001001001 ...]

[0050] The user equipment (200) having I D= 1 , plans to transmit data on 3rd, 6th and 9th transmission frames (300). Transmit pattern vector examples are given for m different user equipment (200) below:

[0051] P1 =[001001001 ...] P2= [010001001 ...] P3= [100010001 ...]

[0052] Pm= [001101001 ...] k In the first embodiment user equipment (200) transmits their transmit pattern vectors to the network node (100). Network node (100) receives transmit pattern vectors from user equipment (200).

[0053] Network node (100) may create a matrix comprising the transmit pattern vectors. An exemplary matrix may be as follows:

[0054] P1 =[00100100100 1]

[0055] P2= [01000100000 1]

[0056] P3= [10001000100 1]

[0057] P4= [10001000100 1]

[0058] P5= [10000010000 0]

[0059] P6= [00001000100 0]

[0060] P7= [10110100100 1]

[0061] — > fc

[0062] 1, 2, ... T

[0063] In another embodiment, network node (100) may monitor user equipment (200) transmit activity and generate transmit pattern vectors based on monitored transmit activity.

[0064] In a possible embodiment transmit pattern vectors may comprise values such as 0, 1, 2, 3 ... for indicating transmit, not transmit, high priority, low priority etc. respectively.

[0065] Network node (100), determines overloaded time frames where number of expected transmissions exceeds number of available transmission slots (310) wherein each time frame has predetermined number of available transmission slots (310). For example, referring to above exemplary matrix, assuming there are 3 available transmission slots (310) in time frame 1 , there would be 4 expected transmission belonging to user equipment (200) 3, 4, 5 and 7. Therefore, time frame 1 would be an overloaded time frame.

[0066] Network node (100) then determines overloading user equipment (200) that will transmit data on overloaded time frames.

[0067] In above example, user equipment (200) 3, 4, 6 and 7 would be overloading user equipment (200).

[0068] Network node (100) then selects at least one overloading user equipment (200). Network node (100) determines available time frames where the number of expected transmissions is less than the number of available transmission slots (310). In above example, time frame 1 1 would be an available time frame since there is no expected transmission on time frame 1 1. Time frame 2 would be an available time frame if available transmission slots (310) are at least two for time frame 2.

[0069] Network frame assigns at least one selected overloading equipment’s at least one overloaded transmission to one of the determined available time frames and transmitting updated transmit pattern vector to the user equipment (200). All user equipment (200) then realizes transmission based on updated transmission pattern vector.

[0070] In a preferred embodiment user equipment (200) may select user equipment (200) in number of overloading user equipment (200) number. For example, if number of available transmission slots (310) is 3 and the number of overloading user equipment (200) is 5, network node (100) would chose 2 overloading user equipment (200).

[0071] In a possible embodiment, network node (100) selects overloading user equipment (200) based on a predetermined priority list.

[0072] In a possible embodiment, a key vector may be generated. When key vector is applied with a XOR operator to a transmit pattern vector to update it. An exemplary equation is given below: h(pt,s) = PL® s where h is a predetermined function and s is the key vector. In order to achieve a balanced matrix (for example having nearly equial number of 1 s) the key vector may be used. Key vector may be generated as follows:

[0073] Accessing to matrix (P) comprising transmit pattern vectors, defining a target matrix (T) where 1 s are distributed as evenly as possible among the colums and generating the key vector (B) by solving PXB=T. Then this matrix may be used for updating transmission patterns of the related user equipment. PXB=T may be solved with the least-squares method.

[0074] A frame counter may be employed in all devices. Devices may be synchronized to network node (100).

[0075] Referring to figure 2, In a second embodiment network node (100) is a non-terrestrial relay comprising a transceiver for transmitting and receiving signals and a processor for processing signals. The primary function of the relay is to listen for uplinks from other devices and transmit them to the network server it is connected to. If it detects activity when it is ON according to agreed vectors, the radio activates additional processor to process the incoming packet. If no activity is detected, the radio returns to sleep mode.

[0076] In more details, in the second embodiment, network node (100) operates in an operating mode where the transceiver listens the channel during the time frames where there is expected transmission and operating in an energy saving mode during the time frames where there is no expected transmission.

[0077] In operating mode processor is in sleep mode and if a transmission is received during the operating mode, the processor is activated for processing received transmission.

[0078] During the energy saving mode, there may be incoming spontaneous uplink data or no activity. To handle spontaneous uplink data, relay operates as follows:

[0079] In energy saving mode network node (100) turns itself on for a predetermined time window for receiving spontaneous uplink request wherein the said predetermined time window is shorter than a single time frame. If no signal is received during the predetermined time window network node (100) switches to sleep mode where it can be activated with a wake up signal. If a spontaneous uplink request is received, network node (100) activates processor to realize the uplink request and waits for an inactivity time window until switching to sleeping mode.

[0080] Implementation: Utilizing HAPS as relay at air segment of non-terrestrial network (NTN) reduces the distance compared to the low earth orbit (LEO) satellite - ground distance which significantly reduces free space losses and thus greatly improves the link budget of the link. According to the European Radio Communications Committee (ERCC) [1], HAPS can use the 47.2-47.5 GHz and 47.9-48.2 GHz frequency bands for such a transmission.

[0081] Current uplink procedure in 5thgeneration new radio (5g-NR) is explained below according to TS 38.300(Rel 17 - 2024) [2],

[0082] Invention may be implemented when the UE (200) detects consistent uplink LBT failures instead of taking actions as specified in TS 38.321 .

[0083]

[0001] Electronic Communications Committee. (2023). The European table of frequency allocations and applications in the frequency range 8.3 kHz to 3000 GHz (ECA Table) (Editorial update). CEPT. Approved October 2021 .

[0084]

[0002] ETSI 3GPP TS 38.300 version 17.7.0 Release 17 43 ETSI TS 138 300 V17.7.0 (2024-02)

Claims

CLAIMS1. A communication method realized by a system comprising a non-terrestrial network node (100) and plurality of user equipment (200) characterized in that comprising steps of;- by the network node (100), accessing a transmit pattern vector comprising indicators whether the UE (200) will transmit data or not in predetermined time frames, transmit pattern vectors and determining overloaded time frames where number of expected transmissions exceeds number of available transmission slots (310) wherein each time frame has predetermined number of available transmission slots (310);- determining overloading user equipment (200) that will transmit data on overloaded time frames;- selecting at least one overloading user equipment (200); determining available time frames where the number of expected transmissions is less than the number of available transmission slots (310);- assigning selected at least one overloading equipment’s at least one overloaded transmission to one of the determined available time frames and transmitting updated transmit pattern vector to the user equipment (200);- by user equipment (200), transmitting data based on the transmit pattern vector.

2. The communication method according to claim 1 , wherein the network node (100) is a relay comprising a transceiver and a processor for processing received signal from transceiver; and the method comprises the steps of;- by the network node (100), operating in an operating mode where the transceiver listens the channel during the time frames where there is expected transmission and operating in an energy saving mode during the time frames where there is no expected transmission.

3. The communication method according to claim 1 , wherein the overloading user equipment (200) are selected based on a predetermined priority list.

4. The communication method according to claim 2, characterized in that comprising the steps of;- in operating mode processor is in sleep mode and if a transmission is received during the operating mode, activating the processor for processing received transmission.

5. The communication method according to claim 3, characterized in that comprising the steps of; in energy saving mode network node (100) turns itself on for a predetermined time window for receiving spontaneous uplink request wherein the said predetermined time window is shorter than a single time frame; if no signal is received during the predetermined time window switching to sleep mode where it can be activated with a wake up signal;- if a spontaneous uplink request is received, activating processor to realize the uplink request and waits for an inactivity time window until switching to sleeping mode.

6. The communication method according to claim 1 , characterized in that the transmit pattern vector comprising indicators relating to a priority degree of the user equipment (200).

7. The communication method according to claim 1 , characterized in that comprising the step of; by the plurality of user equipment (200), transmitting a transmit pattern vector comprising indicators whether the UE (200) will transmit data or not in predetermined time frames.

8. The communication method according to claim 1 , characterized in that comprising the step of; by the network node (100), monitoring transmit patterns of user equipment (200) and generating a transmit pattern vector comprising indicators whether the UE (200) will transmit data or not in predetermined time frames.

9. A system comprising a network node (100) and a user equipment (200) characterized in that the system is configured to realize one of the methods of one of the claims 1-8.

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