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

Abstract

A method for initiating a random access procedure of a wireless device (14a, 14b, 14c; 14), preferably an ambient Internet of Things (IoT) device, in a communication network (10), the method comprising: Determining, by the wireless device (14a, 14b, 14c; 14), a random access information comprising a device identification information, wherein the device identification information is determined, by the wireless device (14a, 14b, 14c; 14), based on identification data provided by an upper layer of a protocol stack of the communication network (10); and Transmitting, by the wireless device (14a, 14b, 14c; 14), a first message of the random access procedure comprising the determined random access information to a node (12, 16) of the communication network (10) for initiating the random access procedure of the wireless device (14a, 14b, 14c; 14).

Description

[0001] R. 416256

[0002] - 1 -

[0003] Specification

[0004] Title

[0005] Method for initiating a random access procedure of a wireless device in a communication network

[0006] The invention concerns a method for initiating a random access procedure of a wireless device, preferably an ambient Internet of Things (loT) device, in a communication network. Further, the invention concerns a wireless device, preferably an ambient loT device, a computer program and a non-transitory computer readable medium.

[0007] Background

[0008] The state of the art in ambient loT devices, as currently studied by 3GPP, encompasses low-complexity, low-energy demanding wireless devices designed for various use-cases, such as inventory management, localization, and sensor data exchange within indoor and outdoor environments. These wireless devices are categorized into three main groups, each with different power consumption and transmission characteristics.

[0009] Type 1 devices have a peak power consumption of approximately 1 pW, comprise an energy storage, and have an initial sampling frequency offset (SFO) of up to 10X ppm. They do not have amplification in the device for either downlink (DL) or uplink (UL) transmission, and their UL transmission is based on backscattering an externally provided carrier wave.

[0010] Type 2a and Type 2b devices have peak power consumption of a few hundred pW, comprise an energy storage, and have an initial SFO of up to 10X ppm. Both types have amplification for DL and / or UL transmission, with Type 2a devices generating UL transmissions by backscattering externally provided carrier waves and Type 2b devices generating UL transmission internally. R. 416256

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[0012] The ambient loT device may be configured to directly and bidirectionally communicate with a user equipment or a base station. The ambient loT device may also be configured to indirectly and bidirectionally communicate with a base station via at least one intermediate node, e.g., a user equipment (UE) or a reader or a relay.

[0013] The ambient loT device may also be configured for receiving downlink transmissions directly from a base station, and for receiving uplinks transmissions to the base station via at least one assisting node. The ambient loT device may alternatively be configured for receiving downlink transmission from the base stations via at least one assisting node, and for transmitting uplinks transmissions directly to the base station.

[0014] The random access procedure for these ambient loT devices may be based on a slotted ALOHA Medium Access (MAC) protocol, where devices access the channel only at the start of a time slot when triggered by the network. In the event of a collision, a resolution mechanism is required to address the simultaneous channel access by multiple ambient loT devices.

[0015] The random access procedure for ambient loT devices can be categorized based on the number of message exchanges and the approach to contention resolution: The procedure may be classified as two-step, three-step, or four-step, depending on the specific sequence of message exchanges involved in initiating and completing the random access process. Additionally, the procedure may be categorized as contention-based or contention-free, based on whether specific mechanisms are employed to mitigate contention and resolve collisions during channel access.

[0016] In conventional wireless networks with random access transmission, UEs transmit a random access preamble via the uplink random access channel. The network responds with a random access response. The UEs respond with a contention resolution identifier (CRID) to be identified by the network. The network then grants the channel to a specified UE based on resources and priority, while other UEs attempt to access the channel at a later random time. R. 416256

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[0018] For a two step random access procedure of an ambient loT device, the first message transmitted to the reader comprises a random access information for identifying the device.

[0019] Disclosure of the invention

[0020] According to a first aspect, there is provided a method for initiating a random access procedure of a wireless device, preferably an ambient Internet of Things (loT) device, in a communication network.

[0021] The method according to the first aspect comprises:

[0022] Determining, by the wireless device, a random access information comprising a device identification information, wherein the device identification information is determined, by the wireless device, based on identification data provided by an upper layer of a protocol stack of the communication network; and

[0023] Transmitting, by the wireless device, a first message of the random access procedure comprising the determined random access information to a node of the communication network for initiating the random access procedure of the wireless device.

[0024] The method according to the first aspect can be understood as a method for wireless communications, specifically of operating the wireless device, preferably the ambient loT device, of the communication network.

[0025] According to a second aspect, there is provided a wireless device, preferably an ambient loT device, of a communication network. The wireless device is configured to execute the method according to the first aspect, or its embodiments.

[0026] According to a third aspect, there is provided a computer program comprising machine-readable instructions to cause the wireless device as defined by the third aspect to execute the method according the first aspect, and / or its embodiments. R. 416256

[0027] - 4 -

[0028] According to a fourth aspect, there is provided a non-transitory computer readable medium having stored thereon the computer program as defined by the sixth aspect.

[0029] The communication network may comprise a wireless network and a core network. The communication network may be configured as a cellular network, preferably according to 3GPP specifications, e.g., according to 3GPP release 18 or beyond, 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.

[0030] The wireless device may be configured as a low-energy or low-power device. The wireless device may have a peak power consumption of less than 1 mW, preferably less than 500 pW, specifically less than 100 pW, according to an embodiment, less than 10 pW, e.g., approximately 1 pW.

[0031] The wireless device is preferably configured for energy harvesting, thus exploiting ambient energy sources, e.g., radio waves, thermal radiation, mechanical vibrations etc. as power supply. The wireless device may or may not comprise an energy storage, e.g., a battery.

[0032] Specifically, the wireless device is different from a Reduced Capability (Redcap) device, a narrow band loT (NB-loT) device, a device for enhanced machine-type communication (eMTC), e.g., due to its lower hardware complexity and / or lower costs, and / or smaller form factors. Additionally, a communication between the wireless device and the node may not be controlled by a Radio Resource Control (RRC) layer. Particularly, a Hybrid Automated Repeat Request (HARQ) procedure may not be deployed or deployable for the communication between the wireless device and the node.

[0033] The wireless device may be arranged on or part of an environmental sensor, e.g., deployed 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, R. 416256

[0034] - 5 - 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 the location and status of assets, vehicles, and inventory in logistics, transportation, and supply chain management applications, an industrial loT sensor and / or actuator to enable monitoring and controlling machinery, equipment, and processes, a smart agriculture device to enable optimizing resource usage and improving crop yields, a smart city infrastructure unit to enable smart street lighting, traffic monitoring, waste management, public safety, and environmental monitoring.

[0035] The node of the communication network may be a radio or wireless node, or a core network node. The radio node may be a base station or a user equipment, e.g., configured as a reader for ambient loT devices, or a relay or an integrated access and backhaul (I AB) .

[0036] The random access procedure may be based on a slotted ALOHA random access MAC protocol. Preferably, the random access procedure is a two step random access procedure.

[0037] The random access procedure preferably comprises at least the transmission of the first message of the random access procedure from the wireless device to the node and the transmission of the second message of the random access procedure from the node to the wireless device.

[0038] The first message may comprise or consist of the random access preamble. The random access preamble comprises the device identification information and may additionally comprise a random number. For a slot-based random access procedure, e.g., slotted ALOHA, the random number is used for determining a slot for transmitting the first message. If the random number is of shorter length, it will be more likely that multiple wireless devices determine the same random, hence the same slot, resulting in an increased probability for collision on the random access channel. If the random number if longer, the probability for R. 416256

[0039] - 6 - channel collision is lower which comes at the price of an increased length of the first message thus increasing computation complexity and causing storage overhead.

[0040] The second message may comprise of consist of the random access response. The random access response may be an echo of the random access information, specifically of the random number and / or the device identification information comprised by the random access information.

[0041] Messages of the random access procedure transmitted between the node and the wireless device, i.e., messages transmitted from the wireless device and received by the node and / or messages transmitted from the node and received by the wireless device, may either be transmitted directly, specifically, on the physical random access channel (PRACH), or indirectly via an intermediate or assisting node of the communication network. As an example, a message received by the wireless device may be transmitted from a core node of the communication network via a radio node, e.g., a base station, of the communication network, to the wireless device, and vice versa.

[0042] The upper layer may include at least one, preferably all, of a group comprising: application layer, transport layer, network layer.

[0043] The proposed solution effectively addresses the challenge of improving the efficiency of a random access procedure, preferably of an ambient loT device. To this end, an ID determination mechanism is provided which enables balancing between unique device identification and meticulously managing energy resources for random access message transmissions in wireless communication networks.

[0044] According to an embodiment, the device identification information is determined by mapping the provided identification data to the device identification information with help of a mapping policy, and the mapping policy preferably comprises a function and / or a table defining the mapping of the provided identification data to the device identification information. R. 416256

[0045] - 7 -

[0046] This allows for a systematic determination of the device identification information based on upper layer data, thus enabling reliable device identification by the node.

[0047] According to an embodiment, the mapping policy, preferably the function and / or the table, is configured to map an input bit sequence representing the provided identification data to an output bit sequence representing the device identification information, and optionally, a length of the output bit sequence is different from a length of the input bit sequence.

[0048] This enables efficient representation of diverse identification data while accommodating varying requirements for device identification in a wireless communication network.

[0049] According to an embodiment, the mapping depends on a further information comprising at least one of a contention information, preferably indicating a number of failed contentions, of the wireless device, or an energy information, preferably indicating an energy level, of the wireless device, or a buffer information, preferably indicating a size or a fill level of a buffer, of the wireless device, or a data information, preferably indicating a criticality of data, specifically in a I the buffer, of the wireless device, or a location information of the wireless device, preferably indicating an identifier of a zone comprising the wireless device, or a use case information of the wireless device, preferably indicating a use case as part of which the method is performed.

[0050] The use case as part of which the method is performed may be a command use case or an inventory use case, e.g., according to 3GPP specifications for ambient loT devices. This contextual dependency allows for adaptive and dynamic determination of device identification information based on the specific operational and environmental conditions of the wireless device.

[0051] According to an embodiment, R. 416256

[0052] - 8 - a I the length of the output bit sequence depends on the further information, and preferably, a content of the device identification information represented by the output bit sequence does not contain the further information.

[0053] This allows to encode the further information implicitly in the device identification information without including it explicitly.

[0054] According to an embodiment, a I the length of the output bit sequence is configured by the node, preferably based on at least one of: a number of wireless devices of the communication network triggered and / or to be triggered, by the node, for initiating a random access procedure of the respective wireless device, or a buffer information regarding a status of a buffer of at least one wireless device of the communication network, or an energy information regarding an energy level of at least one wireless device of the communication network, or a use case information regarding a use case as part of which the method is performed, and wherein the length of the output bit sequence is preferably indicated in a trigger message transmitted from the node to the wireless device for triggering the transmission of the first message.

[0055] The use case as part of which the method is performed may be a command use case or an inventory use case, e.g., according to 3GPP specifications for ambient loT devices. This allows the node to adaptively determine the device identification information based on the operational conditions and network dynamics.

[0056] According to an embodiment, a I the length of the output bit sequence depends on a type of the wireless device. In other words, an information about the type of the wireless device is encoded in a length of the device identification information. This allows for a tailored and type-specific representation of the device identification information.

[0057] According to an embodiment, R. 416256

[0058] - 9 - the function and / or the table of the mapping policy defines a removal of specific bits from the input bit sequence, e.g., by truncating the input bit sequence, or wherein the function and / or the table of the mapping policy defines a modulo operation to be applied on the input bit sequence.

[0059] This allows for rule-based adjustments to the input data to derive the desired device identification information.

[0060] According to an embodiment,

[0061] Determining, by the wireless device, a subset of the provided identification data, preferably representing a specific type of identification data, based on a required length of the output bit sequence, wherein the input bit sequence represents the determined subset of the provided identification data.

[0062] This allows for the selection of relevant subsets of identification data to precisely match the required length of the output bit sequence, ensuring efficient and tailored representation of the device identification information.

[0063] According to an embodiment, the random access information further comprises at least one of a random number, or contention information, preferably indicating a number of failed contentions, of the wireless device, or an energy information, preferably indicating an energy level, of the wireless device, or a buffer information, preferably indicating a size or a fill level of a buffer, of the wireless device, or a data information, preferably indicating a criticality of data, specifically in a I the buffer, of the wireless device, or a location information of the wireless device, preferably indicating an identifier of a zone comprising the wireless device, or a use case information of the wireless device, preferably indicating a use case as part of which the method is performed.

[0064] Here, the further information may be explicitly comprised or indicated or included in the random access information. The further information may be provided from the upper layer(s) of the communication stack or from any other source of R. 416256

[0065] - 10 - information in the communication network. Including the further information enriches the random access information, thus enabling a more detailed and context-aware representation of the wireless device's operational status and environmental context.

[0066] According to an embodiment, the random access information further comprises a failure information regarding an indication of a number of failed attempts of the wireless device for accessing a transmission medium of the communication network by initiating the random access procedure. This provides insight into the device's access attempts and can support decision-making processes related to network access and resource allocation.

[0067] According to an embodiment, the method further comprises:

[0068] Prior to determining the random access information, receiving, by the wireless device, a trigger message transmitted from the node or a further node of the communication network for triggering the random access procedure, wherein the random access information is determined in response to receiving the trigger message.

[0069] The further node may be a core network node or a radio node, e.g., a base station or a user equipment. The trigger message may part of a paging message transmitted over a paging channel of the communication network. This allows for an efficient and coordinated initiation of the random access procedure, thus reducing collisions and contention with other devices attempting to access the network.

[0070] According to an embodiment, the method further comprises:

[0071] Receiving, by the wireless device, a second message of the random access procedure transmitted from the node in response to receiving the first message, wherein the second message comprises o at least partly the random access information comprised by the first message and / or o a resource information about transmission resources allocated for the wireless device. R. 416256

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[0073] The second message may the random access response. The second message may comprise an echo of the random number and / or the device identification information. The second message may additionally or alternatively indicate transmission resources of the network allocated for a transmission or a or multiple retransmission(s) of the wireless device. The resource information may indicate, e.g., a slot or a set of slots allocated for a transmission of the wireless device. Further, the second message may comprise control information. This allows for efficient signaling the wireless device to start with payload transmission in a two step random access procedure.

[0074] According to an embodiment, the method further comprises:

[0075] Transmitting, by the wireless device, in response to receiving the second message, a further message to the node for transmitting data, preferably using the allocated transmission resources.

[0076] The transmitted data may be payload data.

[0077] According to an embodiment, the method further comprises:

[0078] Transmitting, by the wireless device, preferably after transmitting the third message, a further first message of the random access procedure comprising the determined random access information to the node for initiating a further random access procedure of the wireless device.

[0079] The further first message may be a repetition of the first message, preferably comprising the same device identification information, specifically further comprising the same random number. The further first message and the first message may consist of the same bit sequence.

[0080] According to a further aspect of the invention, there is provided a (wireless) communication network comprising at least the wireless device and the node.

[0081] The non-transitory 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- transitory computer readable media may include RAM, ROM, EEPROM, and any other non-volatile storage device.

[0082] Description of the figures R. 416256

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[0084] Exemplary embodiments of the present invention are depicted in the figures, which are not to be construed as limiting the claims, and are explained in greater detail below.

[0085] Fig. 1 schematically illustrates a communication network according to an embodiment of the invention; and

[0086] Fig. 2 schematically illustrate a method according to an embodiment of the invention.

[0087] Fig. 1 schematically illustrates a communication network 10 according to an 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 may comprise a core network and a wireless network.

[0088] The communication network 10 comprises a radio node 12, configured as a user equipment 12, or a reader 12 for an ambient Internet of Things (loT) device, or a relay node acting as a reader, and a plurality of wireless devices 1 a, 14b, 14c, preferably configured as ambient loT devices 14a, 14b, 14c, specifically according to 3GPP specifications. The wireless devices 14a, 14b, 14c are collectively represented by reference sign 14. The communication network 10 further comprises a radio node 16 configured as a base station 16.

[0089] For requesting access to a transmission medium of the communication network 10, the wireless devices 14 are configured to perform a method for initiating a preferably slot-based random access procedure. Here, the random access procedure may be based on a slotted ALOHA random access MAC protocol. I.e., the wireless devices 14 are configured to begin a transmission only at the beginning of a slot. The length of the slot preferably equals the sum of a packet transmission time and a maximum propagation delay in the network to ensure that both transmission and reception of a data packet can be completed within one slot.

[0090] The random access procedure may be established between the respective wireless device 14a, 14b, 14c and the reader 12, or between the respective R. 416256

[0091] - 13 - wireless device 1 a, 14b, 14c and the base station 16. For the latter case, transmission between the wireless devices 14 and the base station 16 may be routed or relayed via the reader 12.

[0092] According to an alternative embodiment, the base station 16 may be configured as a reader for the wireless devices 14. Consequently, messages of the random 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).

[0093] The wireless devices 14 are configured for initiating a random access procedure of the respective wireless device 14 by performing the method according to the first aspect of the invention, and / or its embodiments, as further described in Fig. 2. Specifically, the wireless devices 14 are configured to determine a random access information comprising at least a device identification information (as a first part of the random access information) and preferably additionally a random number (as a second part of the random access information).

[0094] The device identification information is contained in the random access information to identify the respective wireless device 14 to the node 12. The device identification information is determined, by the respective wireless device 14, based on identification data provided by an upper layer (application layer, transport layer, network layer) of a protocol stack of the communication network 10. The identification data may comprise a MAC or IP address etc. of the wireless device, or a combination thereof.

[0095] The random number may be contained in the random access information for requesting timely access to the transmission medium of the communication network 10, specifically for transmission of payload data. For a random access procedure based on a slotted ALOHA MAC protocol, the random number serves for choosing a slot for transmitting a first message of the random access procedure (random access preamble) comprising the determined random access information and preferably additionally the random number itself. Alternatively, the random number may only be used for determining the slot for transmitting the first message which does, however, not comprise the random number, but the device identification information. R. 416256

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[0097] Preferably, the device identification information is determined by mapping the provided identification data to the device identification information with help of a mapping policy. To this end, the mapping policy preferably comprises a function and / or a table defining the mapping of the provided identification data to the device identification information.

[0098] The mapping policy may be configured to map an input bit sequence representing the provided identification data to an output bit sequence representing the device identification information. According to an embodiment, a length of the output bit sequence is different from a length of the input bit sequence.

[0099] The length of the output bit sequence may be either fixed or variable. The length of the output bit sequence may depend on a type of the wireless device, e.g., may be the same fixed length for all wireless devices of the same type, but wireless devices of different types may have different (fixed) lengths. The length of the output bit sequence may also be the same fixed length for all wireless devices in the communication network.

[0100] According to an embodiment, the length of the output bit sequence depends on a further information comprising at least one of a contention information, preferably indicating a number of failed contentions, of the wireless device, or an energy information, preferably indicating an energy level, of the wireless device, or a buffer information, preferably indicating a size or a fill level of a buffer, of the wireless device, or a data information, preferably indicating a criticality / latency of data, specifically in a / the buffer, of the wireless device, or a location information of the wireless device, preferably indicating an identifier of a zone comprising the wireless device, or a use case information of the wireless device, preferably indicating a use case as part of which the method is performed.

[0101] In other words, the length is determined or chosen, by the respective wireless device 14a, in a rule-based manner based on the identification information and the further information. R. 416256

[0102] - 15 -

[0103] According to an alternative embodiment, the length of the output bit sequence is configured by the node 12, preferably based on at least one of: a number of wireless devices of the communication network triggered and / or to be triggered, by the node 12, for initiating a random access procedure of the respective wireless device, or a buffer information regarding a status of a buffer of at least one wireless device of the communication network, e.g., a buffer status report, or an energy information regarding an energy level of at least one wireless device of the communication network, e.g., an energy status report, or a use case information regarding a use case as part of which the method is performed,

[0104] For this embodiment, the length of the output bit sequence is preferably indicated in a trigger message transmitted from the node 12 to the respective wireless device 1 for triggering the transmission of the first message

[0105] A content of the device identification information represented by the output bit sequence comprises the identification data provided by the upper layer at least partially. The device identification information may or may not contain the further information (used for determining the length).

[0106] The random number or random bit sequence as the optional second part of the device identification information is important for determining the transmission slot for the first message. A length of the random number I random bit sequence may be fixed for all types of wireless devices 14, preferably for all types of ambient loT devices 14, in the communication network, e.g., 16 bits, or may be a fixed length for all wireless devices 14 of one type, wherein different types of wireless devices 14 may have random numbers of different lengths.

[0107] The mapping policy is configured to map a content of the input bit sequence representing the provided identification data to a content of the output bit sequence representing the device identification information, wherein the output bit sequence has preferably a defined length. Here, the length of the output bit sequence may be different from the length of the input bit sequence. Specifically, the length of the input bit sequence may vary from a first random access attempt R. 416256

[0108] - 16 - to a second second random access attempt of the same wireless device 1 , or may be fixed.

[0109] The function and / or the table of the mapping policy may define a removal of specific bits from the input bit sequence, e.g., by truncating the input bit sequence. Here, if a MAC address of the wireless device 14 is provided as identification data by the upper layer and used as input bit sequence, a truncated version of the MAC address may be determined as output bit sequence. If an IPv6 and an IPv4 address of the wireless device 14 are provided as identification data by the upper layer and used as input bit sequence, the IPv4 address may be determined as the output bit sequence or another truncated version of the IP addresses.

[0110] Alternatively, the function and / or the table of the mapping policy may define a modulo operation to be applied on the input bit sequence.

[0111] Furthermore, subset of the provided identification data, preferably representing a specific type of identification data, may be determined, by the wireless device 14, a based on a required length of the output bit sequence, wherein the input bit sequence represents the determined subset of the provided identification data. In other words, a part or subset of the identification data used as an input bit sequence may be selected, by the wireless device 14, dependent on the required length (target length) of the output bit sequence. Hence, the wireless device 14 is configured to choose a content (provided by the upper layer) of the device identification information based on the required length.

[0112] As an example, assume that an IP address of the wireless device 14 and a MAC address of the wireless device 14 are provided as identification data by the upper layer. If the length of the output bit sequence representing the device identification information is supposed to be 3 bits, the MAC address as a subset of the identification data may be used as the input bit sequence for the mapping policy. If the length of the output bit sequence representing the device identification information is supposed to be 6 bits, both the MAC address and the IP address may be used as the input bit sequence for the mapping policy. In other words, the device identification information is determined based on the identification data and a requirement on its length. R. 416256

[0113] - 17 -

[0114] Besides, the random access information may further comprise a failure information regarding an indication of a number of failed attempts of the wireless device 1 for accessing a transmission medium of the communication network 10 by initiating the random access procedure. In other words, the number of failed trials is encoded in the random access information by the wireless device 14. This helps the node 12 with scheduling of payload transmissions. The failure information may be represented by a specific number of bits, either explicitly indicating the specific number of failed attempts, or by indicating a failure level, e.g., selected from a group comprising: less than two failed attempts, more than two but less than five failed attempts, more than five but less than ten failed attempts, more than ten but less than 20 failed attempts.

[0115] Moreover, a second message of the random access procedure may be transmitted, by the wireless device, transmitted from the radio node in response to receiving the first message. The second message may comprise at least partly the random access information comprised by the first message and / or a resource information about transmission resources allocated for the wireless device.

[0116] Besides, in response to receiving the second message, a further message may be transmitted, by the wireless device 14, to the node 12 for transmitting (payload) data, preferably using the allocated transmission resources.

[0117] Further, preferably after transmitting the third message, a further first message of the random access procedure may be transmitted to the node 12 by the wireless device 14 for initiating a further random access procedure of the wireless device 14. The further first message may comprise the same random access information, at least the same device identification information.

[0118] Specifically, the random access information, at least the device identification information, determined in a first round of the random access procedure may be re-used for further random access procedures of the same wireless device 14. More precisely, the first message and the further first message may consist of the same bit stream. R. 416256

[0119] - 18 -

[0120] This helps the node in recognizing the wireless device 1 , e.g., for priority handling and access grant mechanism. Correspondingly, priorities regarding different wireless devices 14 may be set based on the device identification information. For instance, in case a wireless device 14 has already successfully gained access to the transmission medium (by transmitting the first message with the device identification information and receiving the second message with an echo of the device identification information), in a further channel access request, another wireless device 14 which has not recently gained access to the channel, may be prioritized by the node 12, for channel access.

[0121] Fig. 2 schematically illustrates a method 100 for initiating a preferably slot-based random access procedure of a wireless device, preferably an ambient Internet of Things (loT) device, in a communication network, e.g., the communication network 10 according to Fig. 1 .

[0122] The method 100 may comprise an optional step 110 of receiving, by the wireless device 14a, a trigger message transmitted from a node 12 or a further node 16 of the communication network for triggering the transmission of a first message of the random access procedure.

[0123] The method 100 comprises a step 120 of determining, by the wireless device 14a, preferably in response to the received trigger message, a random access information comprising a device identification information. Here, the device identification information is determined, by the wireless device 14a, based on identification data provided by an upper layer of a protocol stack of the communication network.

[0124] The method 100 comprises a step of 130 of transmitting, by the wireless device 14a, a first message of the random access procedure comprising the determined random access information to the node 12 for initiating the random access procedure of the wireless device 14a.

Claims

R. 416256- 19 -Claims1 . A method (100) for initiating a random access procedure of a wireless device (1 a, 14b, 14c; 14), preferably an ambient Internet of Things (loT) device(14a, 14b, 14c; 14), in a communication network (10), the method (100) comprising:Determining (120), by the wireless device (14a, 14b, 14c; 14), a random access information comprising a device identification information, wherein the device identification information is determined, by the wireless device (14a, 14b, 14c; 14), based on identification data provided by an upper layer of a protocol stack of the communication network (10); andTransmitting (130), by the wireless device (14a, 14b, 14c; 14), a first message of the random access procedure comprising the determined random access information to a node (12, 16) of the communication network (10) for initiating the random access procedure of the wireless device (14a, 14b, 14c; 14).

2. The method (100) of claim 1 , wherein the device identification information is determined by mapping the provided identification data to the device identification information with help of a mapping policy, and the mapping policy preferably comprises a function and / or a table defining the mapping of the provided identification data to the device identification information.

3. The method (100) of claim 2, wherein the mapping policy, preferably the function and / or the table, is configured to map an input bit sequence representing the provided identification data to an output bit sequence representing the device identification information, and optionally, a length of the output bit sequence is different from a length of the input bit sequence.R. 416256- 20 -4. The method (100) of claim 2 or 3, wherein the mapping depends on a further information comprising at least one of a contention information, preferably indicating a number of failed contentions, of the wireless device (14a, 14b, 14c; 14), or an energy information, preferably indicating an energy level, of the wireless device (14a, 14b, 14c; 14), or a buffer information, preferably indicating a size or a fill level of a buffer, of the wireless device (14a, 14b, 14c; 14), or a data information, preferably indicating a criticality of data, specifically in a / the buffer, of the wireless device (14a, 14b, 14c; 14), or a location information of the wireless device (14a, 14b, 14c; 14), preferably indicating an identifier of a zone comprising the wireless device (14a, 14b, 14c; 14), or a use case information of the wireless device (14a, 14b, 14c; 14), preferably indicating a use case as part of which the method (100) is performed.

5. The method (100) of claim 4, wherein a I the length of the output bit sequence depends on the further information, and preferably, a content of the device identification information represented by the output bit sequence does not contain the further information.

6. The method (100) of one of claims 3 to 5, wherein a I the length of the output bit sequence is configured by the node (12, 16), preferably based on at least one of: a number of wireless devices (14a, 14b, 14c; 14) of the communication network (10) triggered and / or to be triggered, by the node (12, 16), for initiating a random access procedure of the respective wireless device (14a, 14b, 14c; 14), or a buffer information regarding a status of a buffer of at least one wireless device (14a, 14b, 14c; 14) of the communication network (10), or an energy information regarding an energy level of at least one wireless device (14a, 14b, 14c; 14) of the communication network (10), or a use case information regarding a use case as part of which the method (100) is performed,R. 416256- 21 - and wherein the length of the output bit sequence is preferably indicated in a trigger message transmitted from the node (12, 16) to the wireless device (1 a, 14b, 14c; 14) for triggering the transmission of the first message.

7. The method (100) of one of claims 2 to 6, wherein a I the length of the output bit sequence depends on a type of the wireless device (14a, 14b, 14c; 14).

8. The method (100) of one of claims 2 to 7, wherein the function and / or the table of the mapping policy defines a removal of specific bits from the input bit sequence, e.g., by truncating the input bit sequence, or wherein the function and / or the table of the mapping policy defines a modulo operation to be applied on the input bit sequence.

9. The method (100) of one of claims 2 to 8, further comprising:Determining, by the wireless device (14a, 14b, 14c; 14), a subset of the provided identification data, preferably representing a specific type of identification data, based on a required length of the output bit sequence, wherein the input bit sequence represents the determined subset of the provided identification data.

10. The method (100) according to one of the preceding claims, wherein the random access information further comprises at least one of a random number, or contention information, preferably indicating a number of failed contentions, of the wireless device (14a, 14b, 14c; 14), or an energy information, preferably indicating an energy level, of the wireless device (14a, 14b, 14c; 14), or a buffer information, preferably indicating a size or a fill level of a buffer, of the wireless device (14a, 14b, 14c; 14), or a data information, preferably indicating a criticality of data, specifically in a / the buffer, of the wireless device (14a, 14b, 14c; 14), or a location information of the wireless device (14a, 14b, 14c; 14), preferably indicating an identifier of a zone comprising the wireless device (14a, 14b, 14c; 14), orR. 416256- 22 - a use case information of the wireless device (1 a, 14b, 14c; 14), preferably indicating a use case as part of which the method (100) is performed.11 . The method (100) according to one of the preceding claims, wherein the random access information further comprises a failure information regarding an indication of a number of failed attempts of the wireless device (14a, 14b, 14c; 14) for accessing a transmission medium of the communication network (10) by initiating the random access procedure.

12. The method (100) according to one of the preceding claims, further comprising:Receiving, by the wireless device (14a, 14b, 14c; 14), a second message of the random access procedure transmitted from the node (12, 16) in response to receiving the first message, wherein the second message comprises o at least partly the random access information comprised by the first message and / or o a resource information about transmission resources allocated for the wireless device (14a, 14b, 14c; 14).

13. The method (100) according to claim 12, further comprising:Transmitting, by the wireless device (14a, 14b, 14c; 14), in response to receiving the second message, a further message to the node (12, 16) for transmitting (payload) data, preferably using the allocated transmission resources.

14. The method (100) according to one of the preceding claims, further comprising:Transmitting, by the wireless device (14a, 14b, 14c; 14), preferably after transmitting the third message, a further first message of the random access procedure comprising the determined random access information to the node (12, 16) for initiating a further random access procedure of the wireless device (14a, 14b, 14c; 14).R. 416256- 23 -15. A wireless device (14a, 1 b, 14c; 14) of a communication network (10) configured to execute the method (100) according to one of claims 1 to 14.

16. A computer program comprising machine-readable instructions to cause the wireless device (14a, 14b, 14c; 14) according to claim 15 to execute the method (100) according to one of claims 1 to 14.

17. A non-transitory computer readable medium having stored thereon the computer program according to claim 16.

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