Method for initiating a direct access procedure of a wireless device in a communication network

Abstract

A method for initiating a direct access procedure of a wireless device (14a, 14b, 14c; 14), preferably an Ambient-IoT (Internet of Things) device (14a, 14b, 14c; 14), in a communication network (10), wherein the method comprises: - Receiving (110) a trigger message by the wireless device (14a, 14b, 14c; 14) transmitted by a node (12) or another node (16) of the communication network (10) to trigger the transmission of an initial message of the direct access procedure, - Determine (120) whether a condition for transmitting the first message is met by the wireless device (14a, 14b, 14c; 14) in response to the received trigger message; and - Transmission (130) of the first message by the wireless device (14a, 14b, 14c; 14) to the node (12) based on a result of the determination (120), wherein the first message comprises a random value and / or device identification information to request access to a transmission medium of the communication network (10), preferably to request transmission resources from the node (12).

Description

[0001] The invention relates to two corresponding methods for initiating a direct access procedure of a wireless device, preferably an Ambient IoT (Interior of Things) device, in a communication network. The invention further relates to a wireless device, preferably an Ambient IoT device, a node, a computer program, and a non-transient computer-readable medium. background

[0002] The state of the art in ambient IoT devices, as currently being investigated by 3GPP, comprises low-power, low-complexity wireless devices designed for various use cases, such as inventory management, localization, and sensor data exchange in indoor and outdoor environments. These wireless devices are categorized into three main groups, each with different power consumption and transmission characteristics.

[0003] Type 1 devices have a peak power consumption of approximately 1 µW, include an energy storage device, and exhibit an initial sampling rate offset (SFO) of up to 10X ppm. They have no in-device gain for either down-path (DL) or up-path (UL) transmission, and their UL transmission is based on backscattering of an externally provided carrier wave.

[0004] Devices of type 2a and type 2b have a peak power consumption of a few hundred µW, include an energy storage device, and exhibit an initial SFO of up to 10X ppm. Both types feature amplification for DL ​​and / or UL transmission, with type 2a devices generating UL transmissions by backscattering externally supplied carrier waves and type 2b devices generating UL transmissions internally.

[0005] The ambient IoT device can be configured to communicate directly and bidirectionally with a user device or base station. The ambient IoT device can also be configured to communicate indirectly and bidirectionally with a base station via at least one intermediate node, such as a user device (UE), a reader, or a switching center.

[0006] The ambient IoT device can also be configured to receive downlink transmissions directly from a base station and to receive uplink transmissions to the base station via at least one support node. Alternatively, the ambient IoT device can be configured to receive downlink transmissions from the base stations via at least one support node and to transmit uplink transmissions directly to the base station.

[0007] The direct access procedure for these ambient IoT devices can be based on a media access protocol (MAC protocol) of the slot-based ALOHA, with devices accessing the channel only when a time slot starts, triggered by the network. In the event of a collision, a resolution mechanism is required to address simultaneous channel access by multiple ambient IoT devices.

[0008] The direct access procedure for ambient IoT devices can be categorized based on the number of message exchanges and the conflict resolution method: The procedure can be classified as two-stage, three-stage, or four-stage, depending on the specific sequence of message exchanges involved in initiating and completing the direct access process. Furthermore, the procedure can be categorized as conflict-based or conflict-free based on whether specific mechanisms are used to mitigate conflict and resolve collisions during channel access.

[0009] In conventional wireless networks using direct access transmission, UEs transmit a direct access preamble over the upstream direct access channel. The network responds with a direct access response. The UEs respond with a conflict resolution identifier (CRID) that the network intends to identify. The network then grants the channel to a designated UE based on resources and priority, while other UEs attempt to access the channel at a later, random time.

[0010] Existing direct access mechanisms do not take into account the characteristics and capabilities of ambient IoT devices, e.g., limited or no energy storage, low power, energy harvesting operation. Disclosure of the invention

[0011] According to a first aspect, a method for initiating a direct access procedure of a wireless device, preferably an Ambient-IoT (Internet of Things) device, in a communication network is provided.

[0012] The procedure according to the first aspect includes the following: - Receiving a trigger message by the wireless device, transmitted by one or more nodes of the communication network, to trigger the transmission of an initial message of the direct access procedure, - Determine whether a condition for transmitting the first message is met by the wireless device in response to the received trigger message; and - Transmission of the first message to the node by the wireless device based on a result of the determination, wherein the first message includes a random value and / or device identification information to request access to a transmission medium of the communication network, preferably to request transmission resources from the node.

[0013] The method according to the first aspect can be understood as a method for wireless communications, in particular for operating the wireless device, preferably the ambient IoT device, of the communication network.

[0014] According to a second aspect, a method for initiating a direct access procedure of a wireless device, preferably an Ambient-IoT (Internet of Things) device, in a communication network is provided.

[0015] The procedure according to the second aspect includes the following: - Receiving a first message of the direct access procedure by a node of the communication network, which is transmitted by the wireless device in response to receiving a trigger message and based on the result of a determination by the wireless device in response to the received trigger message as to whether a condition for transmitting the first message is met, wherein the first message comprises a random value and / or device identification information for requesting access to a transmission medium of the communication network, preferably for requesting transmission resources from the node; and - Transmission of a second message of the direct access procedure to the wireless device by the node in response to receiving the first message, wherein the second message includes ◯ the random value and / or identification information of the wireless device contained in the first message, and / or ◯ Resource information about transmission and / or retransmission resources allocated to the wireless device.

[0016] The procedure according to the second aspect can be understood as a procedure for communications, in particular for operating the node of the communication network.

[0017] According to a third aspect, a wireless device, preferably an ambient IoT device, is provided to a communication network. The wireless device is configured to execute the method according to the first aspect or its embodiments.

[0018] According to a fourth aspect, a node, preferably a radio node, of a communication network is provided. The node is configured to execute the method according to the second aspect or its embodiments.

[0019] According to a fifth aspect, a computer program with machine-readable instructions is provided to effect that - the wireless device, as defined by the third aspect, performs the method according to the first aspect and / or its embodiments, and / or - the node, as defined by the fourth aspect, performs the procedure according to the second aspect and / or its embodiments.

[0020] According to a sixth aspect, a non-transient, computer-readable medium is provided on which the computer program, as defined by the sixth aspect, is stored.

[0021] The communication network can comprise a wireless network and a core network. The communication network can be configured as a cellular network, preferably according to 3GPP specifications, e.g., 3GPP Issue 18 or later, or as a wireless local area network (LAN), preferably according to IEEE specifications. The communication network comprises at least the wireless device and the node.

[0022] The wireless device can be configured as a low-energy or low-power device. The wireless device can have a peak power consumption of less than 1 mW, preferably less than 500 µW, particularly less than 100 µW, and according to one embodiment less than 10 µW, e.g., approximately 1 µW.

[0023] The wireless device is preferably configured for energy harvesting, thus utilizing ambient energy sources such as radio waves, thermal radiation, mechanical vibrations, etc., as a power supply. The wireless device may or may not include an energy storage device, such as a battery.

[0024] In particular, the wireless device differs from a reduced-capability device (Redcap), a narrowband IoT device (NB-IoT device), or a machine-type enhanced communication device (eMTC), for example, due to its lower hardware complexity and / or lower cost, and / or smaller form factors. Furthermore, communication between the wireless device and the node cannot be controlled by a radio resource control (RRC) layer. Specifically, a hybrid automated retry request (HARQ) procedure cannot be used or applicable for communication between the wireless device and the node.

[0025] The wireless device can be located on or be part of - an environmental sensor, e.g. used in smart buildings, industrial facilities and urban infrastructure to enable environmental monitoring and control, - a smart home device to enable remote monitoring and control of home environments for energy efficiency, security and convenience, - a wearable health and / or fitness tracker to enable personal health and fitness tracking as well as remote patient monitoring in healthcare applications, - an asset tracking device to enable monitoring of the location and status of assets, vehicles and inventory in logistics, transportation and supply chain management applications, - an industrial IoT sensor and / or actuator to enable monitoring and control of a machine system, equipment and processes, - an intelligent agricultural device to enable the optimization of resource use and improvement of crop yields, - a smart city infrastructure unit to enable smart street lighting, traffic monitoring, waste management, public safety and environmental monitoring.

[0026] The node of the communication network can be a radio or wireless node, or a core network node. The radio node can be a base station or a user device configured, for example, as a reader for Ambient IoT devices, or a switching center or an Integrated Access and Return (IAB).

[0027] The direct access procedure preferably includes at least the transmission of the first message of the direct access procedure from the wireless device to the node and the transmission of the second message of the direct access procedure from the node to the wireless device.

[0028] The first message may include or consist of the direct access preamble. The direct access preamble may include a random number and / or device identification information.

[0029] The second message may include or consist of the direct access response. The direct access response may be an echo of the random number and / or device identification information contained in the direct access preamble.

[0030] Direct access procedure messages transmitted between the node and the wireless device—that is, messages transmitted by the wireless device and received by the node, and / or messages transmitted by the node and received by the wireless device—can be transmitted either directly, specifically on the direct access physical channel (PRACH), or indirectly via an intermediate or support node of the communication network. For example, a message received by the wireless device can be relayed from a core node of the communication network to the wireless device via a radio node, such as a base station, of the communication network, and vice versa.

[0031] The proposed solution addresses the challenge of adapting direct access procedures to the characteristics of wireless devices, particularly ambient IoT devices. By incorporating conditional determination, the initiation of the direct access procedure is optimized based on the device's specific operational requirements. This adaptive method ensures that the wireless device responds to trigger messages and transmits the initial message in a manner tailored to its operational capabilities and resource needs. Overall, this improves the efficiency and effectiveness of the direct access procedure, consequently contributing to improved resource utilization.

[0032] According to one embodiment of the first aspect, the condition is preconfigured or included in the received trigger message. The condition can be preconfigured within the operating parameters of the wireless device. Alternatively, the condition can be dynamically included in the trigger message received from the communication network or in any purpose-built control message. The preconfigured condition allows predetermined criteria, such as specific energy levels or buffer states, to be defined within the device. On the other hand, the dynamic inclusion of conditions in the trigger message allows the network to communicate specific requirements or triggers tailored to the operating state of the device. This embodiment offers versatility in determining the conditions for initiating the direct access procedure.

[0033] According to one embodiment of the first aspect, the condition is a device-based condition relating to a state and / or operating mode of the wireless device. The condition can be determined or defined based on specific operating characteristics of the device itself and / or the current and / or predicted operating mode of the device. By basing the condition on the internal state and / or operating mode of the device, the initiation of the direct access procedure is tailored to the specific capabilities and requirements of the device, thus optimizing its interaction with the communication network.

[0034] According to one embodiment of the first aspect, the condition is considered on a device-based basis. - an energy state of an energy storage device of the wireless device and / or - a buffer state of a buffer of the wireless device and / or - a message state of messages contained in a / the buffer of the wireless device, and / or - a location of the wireless device and / or - an operating mode of the wireless device.

[0035] The condition can be based on the energy state of the device's energy storage. For example, the device can initiate the direct access procedure if its energy level is above a (pre)configurable or defined threshold, ensuring that it has sufficient power to participate in communication activities. The device can refrain from initiating the direct access procedure if its energy level is below the (pre)configurable or defined threshold.

[0036] The condition can be based on the device's buffer state, which specifies the buffer fill level, the number of messages stored in the buffer, the type of message in the buffer, the message requirements in the buffer, and / or the priority of messages in the buffer. For example, the device can refrain from initiating the direct access procedure if the buffer fill level is below a (pre)configurable or defined threshold. The device can initiate the direct access procedure if the buffer fill level exceeds the (pre)configurable or defined threshold.

[0037] The condition can be based on the state, e.g., an emergency, packet delay, priority, or an accumulation of a specific type of (individual) message contained in the device's buffer. For example, the device can refrain from initiating the direct access procedure if the packet delay of the messages in the buffer is below a (pre-)configurable or defined threshold. The device can initiate the direct access procedure if the packet delay exceeds the (pre-)configurable or defined threshold.

[0038] The condition can be based on the location of the wireless device, for example, whether the device is located inside or outside a predetermined zone or area. The device can initiate the direct access procedure if it is located inside or outside the zone, and can refrain from initiating the direct access procedure if it is located outside or inside the zone.

[0039] The condition can be based on the operating mode of the wireless device. The operating mode can be either a transmit mode or a power harvesting mode. For example, the device may refrain from initiating the direct access procedure if it is in power harvesting mode. The device may initiate the direct access procedure if it is in transmit mode.

[0040] In other words, the device-based condition can be the following: - an energy condition that represents a relationship between an energy level of the wireless device and a corresponding energy threshold, and / or - a buffer condition that represents a relationship between a number and / or a delay of messages in a buffer of the wireless device and one or more corresponding thresholds, and / or - a message condition that represents a relation between a number and / or a delay of messages in a buffer of the wireless device and one or more corresponding thresholds, - a location condition that represents a relation between the location of the wireless device and a predetermined zone, and / or - an operating mode condition that represents a relationship between an actual or current operating mode of the wireless device and a target operating mode.

[0041] By incorporating these conditions on a device-by-device basis, the direct access procedure is intelligently linked to the device's internal state and operational requirements, enabling efficient and context-aware initiation of communication activities within the network.

[0042] According to one embodiment of the first aspect, the device-based condition considers a power harvesting operating mode of the wireless device. The condition for transmitting the first message might be, for example, that the device is not in power harvesting mode or is not in power harvesting mode for a specific number of upcoming slots. The device may refrain from initiating the direct access procedure if it is in power harvesting mode. For example, if the device is actively harvesting energy from its environment or is expected to do so for a predetermined duration, it may delay initiating the direct access procedure for a defined period or number of slots.By incorporating this condition, the wireless device optimizes its communication activities based on its energy harvesting operating mode, ensuring that the direct access procedure is initiated at a convenient time when energy resources are readily available and stable.

[0043] According to one embodiment of the first aspect, the method further comprises the following: - Receiving a second message by the wireless device, transmitted by the node in response to receiving the first message, wherein the second message comprises the following ◯ the random value and / or identification information of the wireless device contained in the first message, and / or ◯ Resource information about transmission and / or retransmission resources allocated to the wireless device.

[0044] The second message can be the direct access response. The second message can include an echo of the random number and / or device identification information. Additionally or alternatively, the second message can specify network transmission resources to be allocated for a transmission or one or more retransmissions by the wireless device. The resource information can, for example, specify a slot or set of slots to be allocated for a transmission or retransmission by the wireless device. Furthermore, the second message can include control information.

[0045] This enables efficient signaling of the wireless device to proceed to step three of a three / four-step direct access procedure or to begin payload transmission in a two-step direct access procedure.

[0046] According to one embodiment of the first aspect, the method further comprises the following: - Transmitting a third message by the wireless device in response to receiving the second message to the node, preferably using the allocated transmission resources, wherein the third message includes device identification information and / or data.

[0047] The third message can be a third message of the direct access procedure. The third message preferably includes (only) the device identification if the first message does not include the device identification. The third message can also be a payload transmission. This allows the wireless device to effectively utilize the allocated transmission resources by transmitting data or device identification information.

[0048] According to one embodiment of the second aspect, the method comprises the following: - Transmission of a trigger message from the node to the wireless device ◯ to trigger the transmission of the first message of the direct access procedure, and ◯ optionally to at least one further wireless device of the communication network for triggering the transmission of a further first message of a direct access procedure of the at least one further wireless device, wherein the at least one further wireless device is located in a zone with the wireless device.

[0049] The trigger message can be part of a radio paging message transmitted over a radio paging channel of the communication network. The trigger message can, for example, be transmitted by the node to all wireless devices within the zone, such as those of a specific device type or category. The zone can be a spatial area with a predetermined shape and / or size.

[0050] In a wireless network, the trigger message can be transmitted, for example, by a base station to an Ambient IoT device, prompting the device to initiate the direct access procedure. The trigger message can also be transmitted to other Ambient IoT devices located within the same coverage area or zone, ensuring coordinated initiation of the direct access procedure for devices within the designated zone.

[0051] This enables efficient and coordinated initiation of the direct access procedure, consequently reducing collisions and conflicts with other devices attempting to access the network. Furthermore, this embodiment facilitates the synchronized initiation of the direct access procedure for multiple wireless devices within a specific zone, ensuring efficient and coordinated access to the communication network.

[0052] According to one embodiment of the second aspect, the method comprises the following: - Receiving a further first message of a direct access procedure transmitted by a further wireless device of the communication network by a node of the communication network; and - Performing conflict resolution based on the received first and subsequent first messages, with the second message being transmitted based on the result of the conflict resolution.

[0053] The result of conflict resolution can be a random number and / or device identification information that wins the conflict. Performing conflict resolution allows for the effective management of access requests from multiple wireless devices within the communication network.

[0054] According to one embodiment of the second aspect, in the step of performing a channel conflict, the wireless device for obtaining access to the transmission medium is selected based on at least one of the following: - the one or more random values ​​contained in the first and / or subsequent message; - additional information contained in the first and / or subsequent first messages; - a priority assigned to the wireless device and / or the spatial zone containing the wireless device.

[0055] The additional information could include device-specific parameters and / or requirements and / or message priorities and / or other relevant data that assist in conflict resolution. The priority assigned to the spatial zone containing the wireless device can also influence conflict resolution. For example, if the device is located in a higher-priority zone, it may be given priority when accessing the transmission medium. This enables fair and efficient access to the transmission medium, taking into account the specific characteristics and requirements of wireless devices within the network.

[0056] According to another aspect of the invention, a (wireless) communication network is provided with at least the wireless device and the node.

[0057] According to a further aspect of the invention, a method for operating the communication network is provided. The method for operating the communication network comprises the steps of the method according to the first aspect or its embodiments and the steps of the method according to the second aspect or its embodiments.

[0058] The non-transient computer-readable medium is preferably configured to store the computer program to be executed by a processor of the first LAN element and / or the second LAN element and / or the communication network. The non-transient computer-readable media may include RAM, ROM, EEPROM, and any other non-volatile storage device. Description of the characters

[0059] Exemplary embodiments of the present invention are shown in the figures, which are not to be understood as limiting the claims and are explained in more detail below: they show: Fig. 1 schematically a communication network according to an embodiment of the invention; Fig. 2A, B schematically methods according to embodiments of the invention; and Fig. 3 schematically a method according to a further embodiment of the invention.

[0060] Fig. Figure 1 schematically represents a communication network 10 according to one aspect of the invention. The communication network 10 is configured as a cellular communication network 10, preferably according to 3GPP specifications. The communication network 10 can comprise a core network and a wireless network.

[0061] The communication network 10 comprises a radio node 12 configured as a user device 12, or a reader 12 for an Ambient IoT (Internet of Things) device, or a switching node acting as a reader, and a plurality of wireless devices 14a, 14b, 14c, preferably configured as Ambient IoT devices 14a, 14b, 14c, particularly according to 3GPP specifications. The wireless devices 14a, 14b, 14c are collectively represented by a reference numeral 14. The communication network 10 further comprises a radio node 16 configured as a base station 16.

[0062] To request access to a transmission medium of the communication network 10, the wireless devices 14 are configured to initiate a direct access procedure, preferably on a slot basis. Here, the direct access procedure can be based on a direct access MAC protocol of the slot-based ALOHA. That is, the wireless devices 14 are configured to begin transmission only at the start of a slot. The length of the slot is preferably equal to the sum of a packet transmission time and a maximum propagation delay in the network to ensure that both the transmission and reception of a data packet can be completed within a slot.

[0063] The direct access procedure can be established between the respective wireless device 14a, 14b, 14c and the reader 12, or between the respective wireless device 14a, 14b, 14c and the base station 16. In the latter case, the transmission between the wireless devices 14 and the base station 16 can be routed or forwarded via the reader 12.

[0064] According to an alternative embodiment, the base station 16 can be configured as a reader for the wireless devices 14. Consequently, messages of the direct access procedure are transmitted directly between the base station 16 and the wireless devices 14a, 14b, 14c (i.e., without routing them via the radio node 12).

[0065] The wireless devices 14 are configured to initiate a direct access procedure of the respective wireless device 14a, 14b, 14c by performing the method according to the first aspect of the invention and / or its embodiments, as shown in Fig. 2A is described further.

[0066] Node 12 and / or node 16 are configured to initiate a direct access procedure to the at least one wireless device 14a, 14b, 14c by performing the method according to the second aspect of the invention and / or its embodiments, as shown in Fig. 2B is described further.

[0067] Fig. Figure 2 schematically represents two methods according to embodiments of the invention.

[0068] Fig. Figure 2A schematically represents a method 100 for initiating a direct access procedure of a wireless device 14a, preferably an Ambient IoT (Internet of Things) device, in a communication network, e.g. the communication network 10 of Fig. 1, dar.

[0069] The procedure 100 comprises a step 110 for receiving a trigger message transmitted by a node 12 or another node 16 of the communication network, by the wireless device 14a for triggering the transmission of a first message of the direct access procedure.

[0070] The method 100 includes a step 120 to determine whether a condition for transmitting the first message is met by the wireless device 14a in response to the received trigger message.

[0071] Method 100 comprises a step 130 for transmitting a first message by the wireless device 14a to node 12 based on a result of the determination. The first message includes a random value and / or device identification information for requesting access to a transmission medium of the communication network, preferably for requesting transmission resources from node 12. The first message can be configured as a direct access preamble.

[0072] The method may include an optional step 140 for receiving a second message by the wireless device 14a, transmitted by node 12 in response to receiving the first message, wherein the second message comprises the following - the random value and / or identification information of the wireless device contained in the first message, and / or - Resource information about transmission and / or retransmission resources allocated to the wireless device.

[0073] The first message can be configured as a direct access response.

[0074] The method may include an optional step 150 for transmitting a third message of the direct access procedure and / or another message through the wireless device 14a in response to receiving the second message to node 12, preferably using the allocated transmission resources.

[0075] Fig. 2B schematically represents a method 200 for initiating a direct access procedure of a wireless device 14a, preferably an Ambient-IoT (Internet of Things) device, in a communication network.

[0076] The method 200 may include an optional step 210 for transmitting a trigger message through a node 12 of the communication network to the wireless device 14a. - to trigger the transmission of the first message of the direct access procedure and - optionally to at least one further wireless device 14b of the communication network to trigger the transmission of a further first message of a direct access procedure of the at least one further wireless device 14b.

[0077] Here, at least one other wireless device 14b is arranged in a zone with the wireless device 14a.

[0078] Method 200 comprises a step 220 for receiving the first message of the direct access procedure by node 12, which is transmitted by the wireless device 14 in response to receiving the trigger message and based on the result of a determination by the wireless device 14, in response to the received trigger message, as to whether a condition for transmitting the first message is met. The first message comprises a random value and / or device identification information for requesting access to a transmission medium of the communication network, preferably for requesting transmission resources from node 12.

[0079] Procedure 200 may also include an optional step 230 for - Receiving the next first message of the direct access procedure by node 12, which is transmitted by the next wireless device 14b of the communication network.

[0080] Procedure 200 may also include an optional step 240 for - Performing conflict resolution by node 12 based on the received first and subsequent first messages.

[0081] Method 200 comprises a step 250 for transmitting a second message of the direct access procedure through node 12 to the wireless device 14a in response to the reception of the first message, preferably further in response to the reception of the second first message and based on a result of the conflict resolution. The second message comprises - the random value and / or identification information of the wireless device contained in the first message, and / or - Resource information about transmission and / or retransmission resources allocated to wireless device 14a.

[0082] Fig.Figure 3 schematically illustrates a method 300 for performing a direct access procedure of an Ambient IoT device in a communication network 10 according to a further embodiment of the invention. The method 300 can be understood as an improvement of known direct access procedures for triggering an Ambient IoT device or a set of Ambient IoT devices to initiate direct access and data transmission or data retransmission.

[0083] In step 310, a standardized trigger preamble, defined upon receipt of control messages from the network for, e.g., a core network or an application layer, is generated by a radio node of the network. The radio node can be a carrier wave emitter, a reader of Ambient IoT devices (e.g., a dedicated reader), a user device with Ambient IoT capability, a switching center, or a subnetwork management entity.

[0084] In step 320, a trigger message, consisting of or containing the trigger preamble, is sent by the radio node as a unicast, multicast, group cast, or broadcast to the device or set of devices. Alternatively, the trigger message can also be sent by the radio node based on a predefined or specified zone in which the ambient IoT devices are located. In this case, all devices located in the specified zone are triggered for a direct access mechanism upon receipt of the trigger message.

[0085] The trigger message or trigger preambles are transmitted periodically at a fixed rate or on the basis of a signal received by the radio node from the network, e.g., from the core network or from higher layers, e.g., from the application layer.

[0086] In step 320, the trigger message is received by one or more Ambient IoT devices, i.e., one or more Ambient IoT devices are triggered (conditional radio call) to start a direct access procedure.

[0087] The initiation of the direct access procedure is based on checking a condition for transmitting the first message of the direct access procedure. Here, the initiation of the direct access procedure can be based on a set of configured or preconfigured conditions. The condition can, for example, consider the number of existing messages in a device's buffer, the sufficiency of a current energy level for data transmission (e.g., for transmitting a specific number of messages in the buffer), a recovery time (ignoring a radio call and resuming the radio call to reach a specific energy threshold), and / or a packet delay budget (holding the message in the buffer as long as the packet delay is below a threshold).

[0088] In step 330, a random number or value is generated by one or more Ambient IoT devices in a three- or four-step direct access procedure. In a two-step direct access procedure, a random number / value and a device identifier and / or upper-layer data are determined to participate in a conflict to access a channel or transmission medium of the communications network. The random value can be of a fixed or variable size. The random value can be completely random or influenced by several parameters, such as remaining energy and / or message priority, or message requirements such as latency or packet delay budget, and / or it can be regenerated from a previous round of a direct access channel conflict.

[0089] In step 340, the random value, or the random value and additional information such as the device identifier and / or status information and / or upper-layer data, are sent by one or more Ambient IoT devices to the radio node. The transmitted information is preferably contained in a message, in particular an initial message of the direct access procedure, e.g., a direct access preamble. The message is transmitted at a specific time, e.g., upon the start of a slot in the case of direct access by the slot-based ALOHA, or upon the start of a time window defined for channel conflict by the reader or the network.

[0090] In step 350, the random value is (successfully) received and decoded by at least one device on the reader.

[0091] In step 360, based on the received random value from one or more Ambient IoT devices, the reader performs channel conflict resolution to select an Ambient IoT device for channel access. The device selection by the reader could - be completely random and / or - based on random values ​​and / or - based on some additional information that is explicitly modulated in the random value signal, and / or - based on the priority of one or more Ambient IoT devices and / or a priority of the zone in which the set of one or more Ambient IoT devices is located, and / or - based on conditions defined by higher layers or the network.

[0092] In step 370, the same random value or some additional information about the one or more Ambient IoT devices is sent back by the reader.

[0093] Here, in conjunction with the random value returned by the reader to the one or more devices, the reader can also schedule the transmission of one or more upcoming messages. To this end, the reader can specify transmission resources to enable one or more conflict-free transmissions by the one or more devices. Furthermore, the reader can schedule one or more additional messages from the ambient IoT device to the reader to help the one or more devices avoid conflicts and direct access in the future. Additionally, multiple resources can be scheduled for the device to handle new transmissions, improving communication reliability.

[0094] The planned transmission resources, in particular the one or more planned time slots, can be used by the wireless device. - for the transmission of tax messages and / or - for the transmission of buffered messages in a buffer of one or more devices and / or - for retransmission of buffered messages in one / the buffer of one or more devices to increase the reliability of message transmission, and / or - for targeted retransmissions to increase reliability.

[0095] Here, the planning of one or more further messages can be based on a set of prerequisites or conditions.

[0096] In step 380, the information / message transmitted in step 370 is received by the Ambient IoT device. In other words, the device receives the same random value that it generated in step 330.

[0097] In step 390, a next message, preferably a third message, of the direct access procedure can be transmitted by the device. The message can be transmitted with or without conflict. The message can be transmitted in a next slot in the case of a slot-based ALOHA direct access procedure, or in a timeslot scheduled by the reader. The scheduled timeslot, or the one or more allocated radio resources, can be transmitted to the device alongside the second or fourth message of the direct access procedure, or via a control channel in a slot of a different frequency, such as a downlink channel. Before initiating or starting a transmission of a buffered message in the next or scheduled timeslot, the device identifier can be transmitted to the reader.

[0098] In an optional step 400, confirmation of the successful reception of the device identifier and / or the one or more buffered messages by the reader can be transmitted to the device.

Claims

[1] Method (100) for initiating a direct access procedure of a wireless device (14a, 14b, 14c; 14), preferably an Ambient IoT (Internet of Things) device (14a, 14b, 14c; 14), in a communication network (10), wherein the method (100) comprises: - Receiving (110) a trigger message by the wireless device (14a, 14b, 14c; 14) transmitted by a node (12) or another node (16) of the communication network (10) to trigger the transmission of an initial message of the direct access procedure, - Determine (120) whether a condition for transmitting the first message is met by the wireless device (14a, 14b, 14c; 14) in response to the received trigger message; and - Transmission (130) of the first message by the wireless device (14a, 14b, 14c; 14) to the node (12) based on a result of the determination (120), wherein the first message comprises a random value and / or device identification information to request access to a transmission medium of the communication network (10), preferably to request transmission resources from the node (12). [2] Method (100) according to claim 1, wherein the condition is preconfigured or is contained in the received trigger message. [3] Method (100) according to claim 1 or 2, wherein the condition is a device-based condition with respect to a state and / or operating mode of the wireless device (14a, 14b, 14c; 14). [4] Method (100) according to claim 3, wherein the device-based condition considers the following - an energy state of an energy storage device of the wireless device (14a, 14b, 14c; 14) and / or - a buffer state of a buffer of the wireless device (14a, 14b, 14c; 14) and / or - a message state of messages contained in a / the buffer of the wireless device (14a, 14b, 14c; 14), and / or - a location of the wireless device (14a, 14b, 14c; 14) and / or - an operating mode of the wireless device (14a, 14b, 14c; 14). [5] Method (100) according to claim 3 or 4, wherein the device-based condition considers an energy harvesting operating mode of the wireless device (14a, 14b, 14c; 14). [6] Method (100) according to any one of the preceding claims, further comprising: - Receiving (140) a second message by the wireless device (14a, 14b, 14c; 14) transmitted by the node (12) in response to receiving the first message, the second message comprising the following o the random value and / or identification information of the wireless device (14a, 14b, 14c; 14) contained in the first message, and / or o Resource information about transmission and / or retransmission resources allocated to the wireless device (14a, 14b, 14c; 14). [7] Method (100) according to claim 6, further comprising: - Transmitting (150) a third message by the wireless device (14a, 14b, 14c; 14) in response to receiving (140) the second message to the node (12), preferably using the allocated transmission resources, wherein the third message includes device identification information and / or data. [8] Method (200) for initiating a direct access procedure of a wireless device (14a, 14b, 14c; 14), preferably an Ambient IoT (Internet of Things) device (14a, 14b, 14c; 14), in a communication network (10), wherein the method (200) comprises: - Receiving (220) a first message of the direct access procedure by a node (12) of the communication network (10), which is transmitted by the wireless device (14a, 14b, 14c; 14) in response to receiving a trigger message and based on the result of the determination by the wireless device (14a, 14b, 14c; 14) in response to the received trigger message as to whether a condition for transmitting the first message is met, wherein the first message comprises a random value and / or identification information of the device (14a, 14b, 14c; 14) for requesting access to a transmission medium of the communication network (10), preferably for requesting transmission resources from the node (12); and - Transmitting (250) a second message of the direct access procedure by the node (12) to the wireless device (14a, 14b, 14c; 14) in response to receiving the first message, wherein the second message comprises the following o the random value and / or identification information of the wireless device (14a, 14b, 14c; 14) contained in the first message, and / or o Resource information about transmission and / or retransmission resources allocated to the wireless device (14a, 14b, 14c; 14). [9] Method (200) according to claim 8, further comprising: - Transmitting (210) a trigger message by the node (12) to the wireless device (14a, 14b, 14c; 14) o to trigger the transmission of the first message of the direct access procedure, and o optionally to at least one further wireless device (14a, 14b, 14c; 14) of the communication network (10) for triggering the transmission of a further first message of a direct access procedure of the at least one further wireless device (14a, 14b, 14c; 14), wherein the at least one further wireless device (14a, 14b, 14c; 14) is arranged in a zone with the wireless device (14a, 14b, 14c; 14). [10] Method (200) according to claim 8 or 9, further comprising: - Receiving (230) a further first message of a direct access procedure by a node (12) of the communication network (10) transmitted by a further wireless device (14a, 14b, 14c; 14) of the communication network (10); and - Performing (240) a conflict resolution based on the received first and subsequent first messages, the second message being transmitted based on a result of the conflict resolution. [11] Method (200) according to claim 10, wherein in the step of performing a channel conflict the wireless device (14a, 14b, 14c; 14) for obtaining access to the transmission medium is selected on the basis of at least one of the following: - the one or more random values ​​contained in the first and / or subsequent first message; - additional information contained in the first and / or subsequent first messages; - a priority assigned to the wireless device (14a, 14b, 14c; 14) and / or the spatial zone containing the wireless device (14a, 14b, 14c; 14). [12] Wireless device (14a, 14b, 14c; 14) of a communication network (10) configured to perform the method (100) according to any one of claims 1 to 7. [13] Node (12) of a communication network (10) configured to perform the method (200) according to any one of claims 8 to 11. [14] Computer program with machine-readable instructions to cause - the wireless device (14a, 14b, 14c; 14) according to claim 15 performs the method (100) according to any one of claims 1 to 7, and / or - the node (12) according to claim 16 performs the method (200) according to one of claims 8 to 11. [15] Non-transient computer-readable medium on which the computer program according to claim 14 is stored.

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