WO2025212683A1 - Methods and apparatuses for selective retransmissions - Google Patents

Abstract

Methods for selective retransmissions of initial random access transmissions are provided herein. A method includes receiving configuration information, selecting a random access occasion, and transmitting an initial access transmission in the selected random access occasion and including an identifier. If a message including the identifier is not received, the method includes determining to perform retransmission of the initial access transmission based on the received configuration information, and transmitting a retransmission in an access occasion associated with the selected random access occasion. Determining to perform retransmission of the initial access transmission may include determining whether a number of previously failed access attempts exceeds a threshold value. Determining to perform retransmission of the initial access transmission may include determining whether a current energy level is below a threshold. Determining to perform retransmission of the initial access transmission may include determining whether a paging message has been received.

Description

METHODS AND APPARATUSES FOR SELECTIVE RETRANSMISSIONS

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 63/572,799, filed April 1 , 2024, the contents of which are incorporated herein by reference.

BACKGROUND

[0002] Technical specifications for Ambient Internet of Things (loT) technologies are under development by the Third Generation Partnership Project (3GPP). In recent years, loT has attracted much attention in the wireless communication world. More 'things’ are expected to be interconnected for improving productivity efficiency and increasing comforts of life. Further reductions in size, complexity, and power consumption of loT devices may enable the deployment of tens or even hundreds of billion loT devices for various applications and provide added value across the entire value chain. It may be impractical to power all the loT devices by batteries that need to be replaced or recharged manually, which leads to high maintenance cost, serious environmental issues, and even safety hazards for some use cases (e.g., wireless sensor in electric power and petroleum industry).

SUMMARY

[0003] Methods for selective retransmissions of initial random access transmissions are provided herein A method includes receiving configuration information, selecting a random access occasion, and transmitting an initial access transmission in the selected random access occasion and including an identifier. If a message including the identifier is not received, the method includes determining to perform retransmission of the initial access transmission based on the received configuration information, and transmitting a retransmission in an access occasion associated with the selected random access occasion. Determining to perform retransmission of the initial access transmission may include determining whether a number of previously failed access attempts exceeds a threshold value. Determining to perform retransmission of the initial access transmission may include determining whether a current energy level is below a threshold. Determining to perform retransmission of the initial access transmission may include determining whether a paging message has been received. BRIEF DESCRIPTION OF THE DRAWINGS

[0004] A more detailed understanding may be had from the following description, given by way of example in conjunction with the accompanying drawings, wherein like reference numerals in the figures indicate like elements, and wherein:

[0005] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0006] FIG. 1 B is a system diagram illustrating an example wireless transmit/receive unit (WTRU) that may be used within the communications system illustrated in FIG 1A according to an embodiment;

[0007] FIG. 1C is a system diagram illustrating an example radio access network (RAN) and an example core network (CN) that may be used within the communications system illustrated in FIG. 1A according to an embodiment;

[0008] FIG. 1D is a system diagram illustrating a further example RAN and a further example CN that may be used within the communications system illustrated in FIG 1A according to an embodiment;

[0009] FIG. 2 is an illustration showing an example of TAG inventory and access procedures in accordance with RFID specifications;

[0010] FIG. 3 is a diagram illustrating access occasions for initial transmission and retransmission;

[0011] FIG. 4 is a diagram illustrating an example of selective retransmission associated with initial transmission; and

[0012] FIG. 5 is a flow chart illustrating an example of method performed by a device.

DETAILED DESCRIPTION

[0013] FIG. 1A is a diagram illustrating an example communications system 100 in which one or more disclosed embodiments may be implemented. The communications system 100 may be a multiple access system that provides content, such as voice, data, video, messaging, broadcast, etc., to multiple wireless users. The communications system 100 may enable multiple wireless users to access such content through the sharing of system resources, including wireless bandwidth. For example, the communications systems 100 may employ one or more channel access methods, such as code division multiple access (CDMA), time division multiple access (TDMA), frequency division multiple access (FDMA), orthogonal FDMA (OFDMA), singlecarrier FDMA (SC-FDMA), zero-tail unique-word discrete Fourier transform Spread OFDM (ZT-UW-DFT-S- OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0014] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, though itwill be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a station (STA), may be configured to transmit and/or receive wireless signals and may include a user equipment (UE), a mobile station, a fixed or mobile subscriber unit, a subscription-based unit, a pager, a cellular telephone, a personal digital assistant (PDA), a smartphone, a laptop, a netbook, a personal computer, a wireless sensor, a hotspot or Mi-Fl device, an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD), a vehicle, a drone, a medical device and applications (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[0015] The communications systems 100 may also include a base station 114a and/or a base station 114b. Each of the base stations 114a, 114b may be any type of device configured to wirelessly interface with at least one of the WTRUs 102a, 102b, 102c, 102d to facilitate access to one or more communication networks, such as the CN 106, the Internet 110, and/or the other networks 112. By way of example, the base stations 114a, 114b may be a base transceiver station (BTS), a NodeB, an eNode B (eNB), a Home Node B, a Home eNode B, a next generation NodeB, such as a gNode B (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0016] The base station 114a may be part of the RAN 104, which may also include other base stations and/or network elements (not shown), such as a base station controller (BSC), a radio network controller (RNC), relay nodes, and the like. The base station 114a and/or the base station 114b may be configured to transmit and/or receive wireless signals on one or more carrier frequencies, which may be referred to as a cell (not shown). These frequencies may be in licensed spectrum, unlicensed spectrum, or a combination of licensed and unlicensed spectrum A cell may provide coverage for a wireless service to a specific geographical area that may be relatively fixed or that may change over time. The cell may further be divided into cell sectors. For example, the cell associated with the base station 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0017] The base stations 114a, 114b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 116, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT). [0018] More specifically, as noted above, the communications system 100 may be a multiple access system and may employ one or more channel access schemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. For example, the base station 114a in the RAN 104 and the WTRUs 102a, 102b, 102c may implement a radio technology such as Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access (UTRA), which may establish the air interface 116 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and/or High-Speed Uplink (UL) Packet Access (HSUPA).

[0019] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish the air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro). [0020] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access , which may establish the air interface 116 using NR.

[0021] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g , an eNB and a gNB).

[0022] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e , Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), Interim Standard 95 (IS-95), Interim Standard 856 (IS-856), Global System for Mobile communications (GSM), Enhanced Data rates for GSM Evolution (EDGE), GSM EDGE (GERAN), and the like. [0023] The base station 114b in FIG 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 114b may not be required to access the Internet 110 via the CN 106. [0024] The RAN 104 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104 and/or the CN 106 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104 or a different RAT. For example, in addition to being connected to the RAN 104, which may be utilizing a NR radio technology, the CN 106 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0025] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[0026] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1 A may be configured to communicate with the base station 114a, which may employ a cellularbased radio technology, and with the base station 114b, which may employ an IEEE 802 radio technology.

[0027] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1 B, the WTRU 102 may include a processor 118, a transceiver 120, a transmit/receive element 122, a speaker/microphone 124, a keypad 126, a display/touchpad 128, non-removable memory 130, removable memory 132, a power source 134, a global positioning system (GPS) chipset 136, and/or other peripherals 138, among others. It will be appreciated that the WTRU 102 may include any sub-combination of the foregoing elements while remaining consistent with an embodiment.

[0028] The processor 118 may be a general purpose processor, a special purpose processor, a conventional processor, a digital signal processor (DSP), a plurality of microprocessors, one or more microprocessors in association with a DSP core, a controller, a microcontroller, Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), any other type of integrated circuit (IC), a state machine, and the like. The processor 118 may perform signal coding, data processing, power control, input/output processing, and/or any other functionality that enables the WTRU 102 to operate in a wireless environment. The processor 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 118 and the transceiver 120 as separate components, it will be appreciated that the processor 118 and the transceiver 120 may be integrated together in an electronic package or chip.

[0029] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, the transmit/receive element 122 may be an antenna configured to transmit and/or receive RF signals. In an embodiment, the transmit/receive element 122 may be an emitter/detector configured to transmit and/or receive IR, UV, or visible light signals, for example. In yet another embodiment, the transmit/receive element 122 may be configured to transmit and/or receive both RF and light signals. It will be appreciated that the transmit/receive element 122 may be configured to transmit and/or receive any combination of wireless signals.

[0030] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116. [0031] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0032] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit) The processor 118 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 118 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 118 may access information from, and store data in, memory that is not physically located on the WTRU 102, such as on a server or a home computer (not shown).

[0033] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li- ion), etc.), solar cells, fuel cells, and the like.

[0034] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment

[0035] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and/or Augmented Reality (VR/AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors. The sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor, an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, a humidity sensor and the like.

[0036] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e g., associated with particular subframes for both the UL (e.g., for transmission) and DL (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e g., for transmission) or the DL (e g., for reception)).

[0037] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the GN 106.

[0038] The RAN 104 may include eNode-Bs 160a, 160b, 160c, though it will be appreciated that the RAN 104 may include any number of eNode-Bs while remaining consistent with an embodiment. The eNode-Bs 160a, 160b, 160c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.

[0039] Each of the eNode-Bs 160a, 160b, 160c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, and the like. As shown in FIG. 1 C, the eNode-Bs 160a, 160b, 160c may communicate with one another over an X2 interface.

[0040] The CN 106 shown in FIG. 1C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (PGW) 166. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0041] The MME 162 may be connected to each of the eNode-Bs 162a, 162b, 162c in the RAN 104 via an S1 interface and may serve as a control node. For example, the MME 162 may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, bearer activation/deactivation, selecting a particular serving gateway during an initial attach of the WTRUs 102a, 102b, 102c, and the like. The MME 162 may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as GSM and/or WCDMA

[0042] The SGW 164 may be connected to each of the eNode Bs 160a, 160b, 160c in the RAN 104 via the S1 interface. The SGW 164 may generally route and forward user data packets to/from the WTRUs 102a, 102b, 102c. The SGW 164 may perform other functions, such as anchoring user planes during inter-eNode B handovers, triggering paging when DL data is available for the WTRUs 102a, 102b, 102c, managing and storing contexts of the WTRUs 102a, 102b, 102c, and the like.

[0043] The SGW 164 may be connected to the PGW 166, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[0044] The CN 106 may facilitate communications with other networks For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.

[0045] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0046] In representative embodiments, the other network 112 may be a WLAN. [0047] A WLAN in Infrastructure Basic Service Set (BSS) mode may have an Access Point (AP) for the BSS and one or more stations (STAs) associated with the AP. The AP may have access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA The traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. The peer-to- peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.11e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an “ad-hoc” mode of communication.

[0048] When using the 802.11 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width. The primary channel may be the operating channel of the BSS and may be used by the STAs to establish a connection with the AP. In certain representative embodiments, Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) may be implemented, for example in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[0049] High Throughput (HT) STAs may use a 40 MHz wide channel for communication, for example, via a combination of the primary 20 MHz channel with an adjacent or nonadjacent 20 MHz channel to form a 40 MHz wide channel.

[0050] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or 160 MHz wide channels The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two noncontiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC). [0051] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11ah relative to those used in 802.11n, and 802.11ac. 802.11 af supports 5 MHz, 10 MHz, and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.11 ah supports 1 MHz, 2 MHz, 4 MHz, 8 MHz, and 16 MHz bandwidths using non-TVWS spectrum. According to a representative embodiment, 802.11 ah may support Meter Type Control/Machine- Type Communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g , only support for) certain and/or limited bandwidths The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[0052] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802 11 n, 802.11ac, 802.11 af, and 802.11 ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode) transmitting to the AP, all available frequency bands may be considered busy even though a majority of the available frequency bands remains idle.

[0053] In the United States, the available frequency bands, which may be used by 802.11 ah, are from 902 MHz to 928 MHz. In Korea, the available frequency bands are from 917.5 MHz to 923.5 MHz. In Japan, the available frequency bands are from 916.5 MHz to 927.5 MHz. The total bandwidth available for 802.11ah is 6 MHz to 26 MHz depending on the country code.

[0054] FIG. 1 D is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 116. The RAN 104 may also be in communication with the CN 106.

[0055] The RAN 104 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 104 may include any number of gNBs while remaining consistent with an embodiment. The gNBs 180a, 180b, 180c may each include one or more transceivers for communicating with the WTRUs 102a, 102b, 102c over the air interface 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0056] The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using transmissions associated with a scalable numerology. For example, the OFDM symbol spacing and/or OFDM subcarrier spacing may vary for different transmissions, different cells, and/or different portions of the wireless transmission spectrum. The WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using subframe or transmission time intervals (TTIs) of various or scalable lengths (e.g., containing a varying number of OFDM symbols and/or lasting varying lengths of absolute time).

[0057] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement DC principles to communicate with one or more gNBs 180a, 180b, 180c and one or more eNode-Bs 160a, 160b, 160c substantially simultaneously. In the non- standalone configuration, eNode-Bs 160a, 160b, 160c may serve as a mobility anchor for WTRUs 102a, 102b, 102c and gNBs 180a, 180b, 180c may provide additional coverage and/or throughput for servicing WTRUs 102a, 102b, 102c.

[0058] Each of the gNBs 180a, 180b, 180c may be associated with a particular cell (not shown) and may be configured to handle radio resource management decisions, handover decisions, scheduling of users in the UL and/or DL, support of network slicing, DC, interworking between NR and E-UTRA, routing of user plane data towards User Plane Function (UPF) 184a, 184b, routing of control plane information towards Access and Mobility Management Function (AMF) 182a, 182b and the like. As shown in FIG. 1D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[0059] The CN 106 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While the foregoing elements are depicted as part of the CN 106, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[0060] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different protocol data unit (PDU) sessions with different requirements), selecting a particular SMF 183a, 183b, management of the registration area, termination of non-access stratum (NAS) signaling, mobility management, and the like. Network slicing may be used by the AMF 182a, 182b in order to customize CN support for WTRUs 102a, 102b, 102c based on the types of services being utilized WTRUs 102a, 102b, 102c. For example, different network slices may be established for different use cases such as services relying on ultra-reliable low latency (URLLC) access, services relying on enhanced massive mobile broadband (eMBB) access, services for MTC access, and the like The AMF 182a, 182b may provide a control plane function for switching between the RAN 104 and other RANs (not shown) that employ other radio technologies, such as LTE, LTE-A, LTE-A Pro, and/or non-3GPP access technologies such as WiFi.

[0061] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 106 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 106 via an N4 interface. The SMF 183a, 183b may select and control the UPF 184a, 184b and configure the routing of traffic through the UPF 184a, 184b. The SMF 183a, 183b may perform other functions, such as managing and allocating UE IP address, managing PDU sessions, controlling policy enforcement and QoS, providing DL data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[0062] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 104 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi-homed PDU sessions, handling user plane QoS, buffering DL packets, providing mobility anchoring, and the like.

[0063] The CN 106 may facilitate communications with other networks For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 112, which may include other wired and/or wireless networks that are owned and/or operated by other service providers In one embodiment, the WTRUs 102a, 102b, 102c may be connected to a local DN 185a, 185b through the UPF 184a, 184b via the N3 interface to the UPF 184a, 184b and an N6 interface between the UPF 184a, 184b and the DN 185a, 185b.

[0064] In view of FIGs. 1A-1 D, and the corresponding description of FIGs. 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 114a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-b, UPF 184a-b, SMF 183a-b, DN 185a-b, and/or any other device(s) described herein, may be performed by one or more emulation devices (not shown). The emulation devices may be one or more devices configured to emulate one or more, or all, of the functions described herein. For example, the emulation devices may be used to test other devices and/or to simulate network and/or WTRU functions.

[0065] The emulation devices may be designed to implement one or more tests of other devices in a lab environment and/or in an operator network environment. For example, the one or more emulation devices may perform the one or more, or all, functions while being fully or partially implemented and/or deployed as part of a wired and/or wireless communication network in order to test other devices within the communication network. The one or more emulation devices may perform the one or more, or all, functions while being temporarily implemented/deployed as part of a wired and/or wireless communication network The emulation device may be directly coupled to another device for purposes of testing and/or performing testing using over-the-air wireless communications.

[0066] The one or more emulation devices may perform the one or more, including all, functions while not being implemented/deployed as part of a wired and/or wireless communication network. For example, the emulation devices may be utilized in a testing scenario in a testing laboratory and/or a non-deployed (e.g., testing) wired and/or wireless communication network in order to implement testing of one or more components. The one or more emulation devices may be test equipment. Direct RF coupling and/or wireless communications via RF circuitry (e.g., which may include one or more antennas) may be used by the emulation devices to transmit and/or receive data.

[0067] A listing of abbreviations and acronyms as may be used herein is provided below.

ACK Acknowledgement

AMF Access and Mobility management Function

BLER Block Error Rate

BWP Bandwidth Part

CAP Channel Access Priority

CAPC Channel access priority class

CCA Clear Channel Assessment

CCE Control Channel Element

CE Control Element

CG Configured grant or cell group

CP Cyclic Prefix

CP-OFDM Conventional OFDM (relying on cyclic prefix)

CQI Channel Quality Indicator

CRC Cyclic Redundancy Check

CSI Channel State Information

CW Contention Window

CWS Contention Window Size

CO Channel Occupancy

CW Carrier Wave

DAI Downlink Assignment Index

DCI Downlink Control Information

DFI Downlink feedback information

DG Dynamic grant DL Downlink

DM-RS Demodulation Reference Signal

DRB Data Radio Bearer eLAA enhanced Licensed Assisted Access

FeLAA Further enhanced Licensed Assisted Access

HARQ Hybrid Automatic Repeat Request

IAB Integrated Access and Backhaul

LAA License Assisted Access

LBT Listen-Before-Talk

LMF Location Management Function

LTE Long Term Evolution e.g. from 3GPP LTE R8 and up

NACK Negative ACK

MCS Modulation and Coding Scheme

MIMO Multiple Input Multiple Output

NR New Radio

OFDM Orthogonal Frequency-Division Multiplexing

PHY Physical Layer

PID Process ID

PO Paging Occasion

PRACH Physical Random Access Channel

PSS Primary Synchronization Signal

RA Random Access (or procedure)

RACH Random Access Channel

RAR Random Access Response

RCU Radio access network Central Unit

RF Radio Front end

RFID Radio Frequency Identification

RLF Radio Link Failure

RLM Radio Link Monitoring

RNTI Radio Network Identifier

RO RACH occasion

RRC Radio Resource Control

RRM Radio Resource Management

RS Reference Signal

RSRP Reference Signal Received Power

RSSI Received Signal Strength Indicator

SDU Service Data Unit SIB System Information Block

SRS Sounding Reference Signal

SS Synchronization Signal

SSB Synchronization Signal Block

SSS Secondary Synchronization Signal

SWG Switching Gap (in a self-contained subframe)

SPS Semi-persistent scheduling

SUL Supplemental Uplink

TB Transport Block

TBS T ransport Block Size

TRP Transmission / Reception Point

TSC Time-sensitive communications

TSN Time-sensitive networking

UPF User Plane Function

UL Uplink

URLLC Ultra-Reliable and Low Latency Communications

WBWP Wide Bandwidth Part

WL N Wireless Local Area Networks and related technologies (IEEE 8O2.xx domain)

[0068] Most of the existing wireless communication devices currently deployed are powered by batteries that needs to be replaced or recharged manually The automation and digitalization of various industries open numbers of new markets requiring new loT technologies of supporting batteryless devices with no energy storage capability or devices with energy storage that do not need to be replaced or recharged manually. The form factor of such devices must be reasonably small to convey the validity of target use cases.

[0069] An example type of application described in in 3GPP TR 22.840 is asset identification, which presently relies upon barcodes and RFID tags. An advantage of these two technologies is the ultra-low complexity and small form factor of the tags. However, the limited reading range of a few meters usually requires handheld scanning which leads to labor intensive and time-consuming operations, or RFID portals/gates which may be costly to deploy. Moreover, the lack of an interference management scheme may result in severe interference between RFID readers and capacity problems, especially in the case of dense deployments. It may be difficult to support large-scale networks with seamless coverage for RFID.

[0070] The scope of work currently underway for ambient loT is described as follows. RAN2 is currently studying which functions are needed for an Ambient loT compact protocol stack and lightweight signaling procedure to enable DO-DTT and DT data transmission. For example, such functions could include paging, random access, data transmission, including necessary radio resource control aspects, respecting the limitation in the General Scope, interactions with upper layers, and other functionalities not listed above, if found essential. RFID procedures are described herein [0071] FIG. 2 is an illustration showing an example of aTAG inventory and access procedure in accordance with RFID specifications. Steps are shown in which an interrogator inventories and accesses a single Tag.

[0072] In the illustration of FIG. 2, the interrogator 201 and the tag 202 are configured to exchange messages as described herein. As shown at step 210, the interrogator sends a message, issuing a Query, QueryAdjust, or QueryRep message. A Query, QueryAdjust, or QueryRep message may indicate a start of an access occasion, which may be an indication of a slot. At step 220, a tag that receives the Query, QueryAdjust, or QueryRep message may respond with a 16-bit random number or pseudo-random number (RN16) if the indicated slot is slot 0. In some examples not shown in FIG. 2, a tag 202 that receives the Query, QueryAdjust, or QueryRep message may not reply if the indicated start of the access occasion is not 0.

[0073] FIG. 2 illustrates a scenario where the indicated slot is slot 0 Thus, as shown in step 220, the tag 202 responds to the Query, QueryAdjust, or QueryRep sending an indication of the RN 16.

[0074] As shown at step 230, the interrogator 201 sends an acknowledgment (ACK) in response to the RN16 (e.g., 16-bit random number), indicating the same RN16 that the interrogator 201 received.

[0075] As shown at step 240, the tag 202 responds to the ACK message by sending a message containing one or more bitfields that define characteristics of the tag 202. For example, the bitfields may include one or more of a protocol-control (PC) word and/or an extended protocol control (XPC) word, which indicate characteristics of the tag 202 such as metadata or memory availability, as well as an electronic product code (EPC) which may be a unique identifier assigned to the tag 202.

[0076] As shown at step 250, the interrogator 201 issues a Req_RN command that contains the same RN16 that was previously received and transmitted. Upon receiving the Req_RN command, the tag 202 determines whether the RN16 included in the Req_RN command is valid. If the RN16 is not valid the tag 202 does not reply to the Req_RN command. If, as shown in FIG. 2, the RN16 is valid, then the tag 202 responds with a handle as shown at 260, which may be a new RN16. The handle may serve as a unique, short-term identifier for the tag 202, enabling the interrogator 201 to continue interact with the tag 202 during a session. For example, the handle may operate as a CRC, enable the tag 202 to check the validity of a received command.

[0077] As shown at step 270, the interrogator 201 accesses the tag 202, using the handle indicated by the tag 202 as a parameter. At step 280, upon receiving a subsequent command that includes the handle, the tag 202 verifies the handle (e g., performs a validity (CRC) check for the received command).

[0078] A short description of current techniques as they relate to AloT development is provided herein. In 3GPP technical specifications, AloT design may re-use many aspects of RFID, including the inventory procedure. In the AloT inventory procedure, multiple devices may fail to access and send messages to a reader due to one or more collisions within a selected access occasion. The devices that experience collisions do not get a chance to retransmit until the next inventory round.

[0079] This could delay paged device or reporting of sensor data for these devices significantly, especially if the inventory procedure is not performed frequently. In other words, devices that experience collisions may experience delays in receiving paging, or the devices may be unable to report sensing data without delays. This approach may not be acceptable if we want to extend AloT to a wide range of use cases, which may include differentiation between the devices in terms of priority. Also, it may not afford the reader (network or intermediate node) with sufficient flexibility when some AloT devices should be prioritized over others.

[0080] A short description of at least one problem addressed herein is provided in the following paragraphs. One problem may be how to introduce a retransmission procedure after a collision in an RFID-like inventory procedure in which one or more device(s) are allowed to perform retransmissions in the same round (i.e., based on some prioritization conditions and configurations). The “same round” as referred to herein may refer to the round during which a collision occurs or is detected.

[0081] A summary of various solutions described herein is provided as follows. Some solutions may involve selective retransmission associated with an initial transmission. After a collision is detected with a transmission, a device determines whether to perform retransmission in the subsequent access occasions in the same round based on a condition related to device prioritization A device may take one or more of the following actions or steps. The device may receive a first message initiating a query round (e.g., query message) which may include a threshold number of failed access attempts; a threshold of energy level; a list of device IDs (e g., high priority); the paged device ID; a total number of access occasions in this round; a number of access occasions for initial transmission and a number of access occasions associated with each of the initial transmission access occasion in this round (e.g., for retransmission); and/or an indication of the number of repetitions per each of the access occasions (e.g., retransmission).

[0082] The device may select a random access occasion within the number of access occasions with initial transmission in this round. The device may perform an initial transmission (e.g., including a device ID) in the selected access occasion.

[0083] If the device receives a response to the transmission with the same device ID in the transmission (i.e., the received response includes the same device ID), the device may assume successful completion of the access attempt in this round; otherwise (e.g., in the case a collision is detected with the initial transmission), the device may determine whether to perform retransmission in the same round based on one or more of the following conditions. The conditions may be, include, or involve one or more of the following: the number of failed access attempts in previous rounds are above the threshold (i.e., the threshold number of failed access attempts); the current energy level is below the threshold (i.e., the energy level threshold); the device ID is included in the list of devices associated with this access round (i.e., the received list of device IDs); and/or the device ID is (or matches) the paged device ID in this access round.

[0084] If the device ID matches the paged device ID, the device may select one or more random access occasions within the number of access occasions associated with the initial transmission access occasion used for the initial transmission in this round The device may determine the number of repetitions for each of the selected one or more access occasions based on the indication of the number of repetitions per each of the access occasions. The device may perform retransmissions with the determined number of repetitions in each of the selected one or more access occasions in this round.

[0085] If at least one condition is satisfied (e.g., other than device ID is the paged device ID), the device may select one or more random access occasions within the number of access occasions associated with the initial transmission access occasion used for the initial transmission in this round. The device may perform retransmissions in the one or more selected access occasions in this round. Otherwise (e.g., none of conditions are satisfied), the device may wait for a next or following query round.

[0086] As a benefit, these solutions may provide that one or more prioritized devices are allowed to perform retransmissions within the number of access occasions in the same round. The device may achieve a successful access attempt based on the retransmission in the same round

[0087] Common terminology and aspects applicable to multiple solutions may be described as follows.

[0088] In a first topology, topology 1, the AloT device may directly and bidirectionally communicate with a base station or network. The communication between the base station and the AloT device includes AloT data and/or signalling. This topology includes the possibility that the base station transmitting to the AloT device is a different from the base station receiving from the AloT device. In a second topology, topology 2, the AloT device communicates bidirectionally with an intermediate node between the device and base station. In this topology, the intermediate node may be a relay, IAB node, WTRU, repeater, etc. that may be capable of AloT. The intermediate node may transfer AloT data and/or signalling between base station and the AloT device.

[0089] In this application, the terms device, Ambient loT device, and/or TAG may be used interchangeably to mean (or refer to) the AloT device that is being inventoried/queried by the reader. The term reader may refer to the entity that queries the AloT device, either directly, or via an intermediate WTRU in the second topology. The term reader in topology 2 may also refer to the intermediate WTRU. As a result, the term reader may refer to a network node or a WTRU, depending on the context and/or the topology. The term reader as used with respect to topology 1 may also refer to a network. As used herein, the terms reader, reader WTRU, network, Interrogator, intermediate WTRU, may be used interchangeably to refer to the reader.

[0090] Inventory terminology as used herein is described as follows. Herein, the term query round may refer to the overall inventory procedure of a reader triggering access by multiple devices using a sequence of messages. Specifically, the inventory procedure may refer to a single round of attempts to have each device respond or attempt to respond with its device ID or access ID. Specifically, the inventory procedure may refer to a set of access occasions that may have 0 or at least 1 device respond within the access occasion. An inventory procedure may be carried out similar to a legacy RFID procedure. Although referred to herein as an inventory procedure, it may be referred to differently in device requirements or specifications (e g., as a query procedure, paging procedure, etc.)

[0091] Access occasion terminology as used herein is described as follows. Herein, the term access occasion may refer to the opportunity for device transmission that may be delimited by the transmission of a query message or query rep message (or similar). Specifically, a device may perform a transmission in an occasion by performing an AloT transmission in a defined time following the query rep associated with that transmission. Alternatively, or additionally, an access occasion may include both a time aspect and a frequency aspect Specifically, a device may determine an occasion as a transmission following a specific query or query rep, and by transmitting on one of a number of frequencies (e.g., FDM). Wherever solutions indicate selection of an occasion, they can apply equivalently to selection of only a time component and/or selection of a frequency component.

[0092] Common solution components are described herein. A description of Random access in RFIDbased systems is provided below. According to an RFID inventory procedure, a query message may initiate one round of inventory procedure and a query message including a parameter Q, which may be used by the Reader (Interrogator/internode/network) to regulate the probability of a device response. Upon receiving a Query message (or QueryAdjust) message, an AloT device may select its slot counter as a value between 0 and 2^Q-¹ derived from the parameter Q. The device may decrement their slot counter every time upon receiving a QueryRep. When the device's slot counter reaches zero, the device may transmit (or perform backscattering to indicate) a 16-bit random number or pseudo-random number (RN16) generated by the device. When more than one device replies in the same slot counter at the same time, a collision may happen.

[0093] The random access (or RACH) procedure is described in further detail. Herein, the RACH procedure may be initiated with a device’s first transmission during an access occasion (e.g., slot counter in random access RFID). Such transmission may be similar to the transmission by the device in an RFID inventory procedure used to indicate the device ID. Such transmission may be followed by a confirmation of the device ID by the reader. For example, the reader may confirm the device ID by sending a transmission that includes the device ID. Such transmission may be initiated by the device upon reception of an indication that an access occasion has been started. As with RFID, the indication of a start of an access occasion may be signaled in a message from the reader (e.g., in the Query or QueryAdjust or QueryRep message).

[0094] A device may initiate a RACH procedure only in a specific access occasion. The access occasions may be delimited by certain transmissions by the reader (e.g., similar to an RFID procedure where each QueryRep message denotes the start of an occasion). Alternatively, or additionally, a device may initiate a RACH procedure in multiple occasions. Alternatively, or additionally, a device may initiate a RACH procedure in an occasion indicated by the reader in the Query message.

[0095] A device may perform contention-based or contention free RACH procedure. In a contention-free RACH procedure, the device may send a different set of information compared to a contention-based RACH procedure. In a contention-based RACH procedure, the device may include its device ID while transmitting based on its access occasion. In some examples, the device ID may be a number (e.g., 16-bit random number, 16-bit pseudo-random number). In a contention-free RACH procedure, the device may include no device ID. Specifically, in the case the initial message which starts the occasion (e.g., the QueryRep or similar message) includes a device ID for that occasion, the device may initiate a contention-free RACH procedure and may transmit any of the other configuration related information, or buffer status without including a device ID. [0096] Contention resolution during a RACH procedure may filter subsequent transmissions from the reader. Contention resolution may, for example, determine whether a device should decode messages (e.g., messages indicated as unicast) in a given occasion. Contention resolution may involve a device receiving confirmation of the device ID (e.g., same device ID) sent in the previous RACH message (e.g., access attempt). If the device does not receive a message with the device ID matching the transmitted device ID, the device may ignore or filter out subsequent messages indicated as unicast The device may assume that the access attempt is failed.

[0097] Alternatively, or additionally, each unicast message destined to a device following contention resolution (i.e. , after the message from the reader with the device ID) may include the same device ID, and the device may filter out or ignore all (or some) messages containing that non-matching device ID, while it may forward all (or some) messages to upper layers containing the matching device ID.

[0098] A first set of solutions may involve selective retransmissions associated with an initial transmission. Procedures discussed herein may be directly described from the device perspective. For example, procedures discussed herein may be described with a focus on steps performed by a reader or on steps performed by a device (i.e., tag, AloT tag, etc.).

[0099] Steps relating to receiving a configuration are described herein. A reader may transmit a message to device(s) when a new query round (e.g., inventory round) is initiated. The transmitted message may include a configuration for a RACH procedure (e.g , total number of access occasions, access occasions for initial transmission and retransmission) applicable/valid for this round (e.g., one round). The configuration may be applicable/valid for the next number of rounds with an indication of rounds (e.g., multiple rounds). The device may perform a RACH procedure for initial transmission in a selected access occasion and may perform retransmissions if the initial transmission is failed.

[0100] In some examples, a device may receive a configuration or configuration information via a broadcast and/or via a unicast message. The device may receive the configuration or configuration information via a broadcast message. The message may be a round initiated message, a Query message, a QueryAdjust message, a QueryRep message, an RRC message, SIB message, a paging message, or any other logically equivalent message. The device may receive the configuration or configuration information via a unicast message (e.g , RRC reconfiguration message).

[0101] In some examples, a device may receive a configuration or configuration information for initial transmissions in this round. For example, the configuration information may indicate one or more access occasions (e.g., slot counters in RFID inventory procedure) will be used for initial transmission in this round. In some examples, a device may receive configuration information indicating one or more access occasions (e.g., slot counters in RFID inventory procedure) for retransmission. A configuration for retransmission may be used when the device needs to perform a retransmission according to or subsequent to the failure of the initial transmission. [0102] The configuration of one or more access occasions for retransmission may be associated with each of the one or more access occasions for initial transmission in this round. For example, the configuration may include a specific association with one or more access occasions for retransmission and each of the access occasions of the initial transmission. For example, the configuration may include a mapping between one or more access occasions for initial transmission to one or more configured or preconfigured access occasions for retransmission.

[0103] In one example, the one or more configured or preconfigured access occasions for retransmission in this round may be activated upon receiving an indication and/or message (e.g., an indication for activation, an activation for additional access occasion message, and/or a QueryAdjust message). The configured or preconfigured one or more access occasions for retransmission may be activated in the same round. Upon receiving the indication (e.g., during the RACH procedure), the device may extend the additional access occasions in this round with maintaining the selected access occasion for initial transmission (e.g., does not reset or change the selection of the initial transmission).

[0104] In some examples, (e g., during the RACH procedure) a device may receive configuration information (e.g , one or more configurations or reconfigurations) for the extended/additional one or more access occasion for retransmission associated with each of the one or more access occasions for initial transmission in this round (e.g., RRC reconfiguration message, QueryAdjust message, and/or QueryAdjust- like message). Upon receiving the configuration information, configuration, or reconfiguration, the device may extend additional access occasions for retransmissions in the same round while maintaining the selected access occasion for initial transmission (e.g., a configuration or reconfiguration may not reset or change the selection of the initial transmission).

[0105] Actions and/or steps for receiving conditions for retransmission are described herein. A device may determine whether to perform retransmission or not (e.g., in the same round) based on the one or more conditions when retransmission is necessary. Performing retransmission in the same round may include or may refer to transmitting a response to a broadcast message by the reader, performing a RACH procedure, performing transmission of a message, etc. following a previous failure determined by the device. Failure may include or may refer to failure of the RACH procedure, failure to receive acknowledgement by the reader, failure to perform transmission due to, for example, lack of energy, etc.

[0106] In some examples, a device may receive a message including or indicating one or more conditions that are associated with, applicable to, or used for round(s) for retransmission from a reader. The one or more conditions may be applicable/valid for this round (e.g., one round) and/or a next number of rounds with an indication of rounds (e.g., multiple rounds). A device may further receive configuration information for determining which round(s) should be considered for retransmission.

[0107] When the device needs to perform retransmission due to a failure of an initial transmission, or a previous retransmission, the device may perform the retransmission in the same round when one or more conditions (e.g. one or more of the indicated conditions) are satisfied. [0108] In some examples, a device may receive a configuration (e.g., information indicating the configuration) via a broadcast and/or via a unicast message. The device may receive the configuration (e.g., information indicating the configuration) via a broadcast message. This may be, for example, a round-initiated message, Query message, QueryAdjust message, QueryRep message, an RRC message, SIB message, and/or paging message, or any other logically equivalent message. The device may receive the configuration or configuration information via a unicast message (e.g., an RRC reconfiguration message).

[0109] In some examples, the device may determine whether to perform the retransmission based on one or more conditions described in the following paragraphs.

[0110] The device may determine whether to perform the retransmission based on an energy level. In some examples, a device may be configured with a threshold for or associated with an energy level. For example, when the current energy level of the device is below or lower than the configured threshold, the device may perform the retransmission based on subsequent access occasions for retransmission in this round (i.e., the same round).

[0111] In some examples, a device may be configured with a condition based on the amount of time that the device can perform transmission for given the current energy level and/or required transmit power. For example, if the device’s stored energy allows it to transmit and/or receive for an amount of time smaller than a configured threshold (e g., a threshold time duration), or some value computed by the device based on the inventory procedure configuration, the device may perform a retransmission. For example, if the device only has sufficient stored energy enabling the device to transmit and/or receive for a given amount of time, and the given amount of time is smaller than the configured threshold or some other value, the device may perform a retransmission.

[0112] The device may be prioritized over other devices in this round because the current energy level of the device is low. Specifically, if an energy level of the device is lower than the configured threshold, the device may not perform initial transmission and/or retransmission in the next round due to performing energy harvesting in near future for energy charging. In contrast, if an energy level of the device is higher than the threshold, the device may assume that the device has enough energy and may be enabled to perform an initial transmission and associated with the retransmission in the next round instead of performing energy harvesting. [0113] The device may determine whether to perform the retransmission based on a number of failures. In some examples, a device may receive a threshold (e.g., information indicating a threshold) of or associated with the number of failed access attempts in the previous round (where, for example, a failed access attempt may involve transmitting a device ID for initial transmission but receiving a different device ID from a reader and/or receiving no response after transmitting a device ID from a reader). To estimate the number of failures, the device may maintain a counter for counting/estimating the number of failed attempts and/or UL transmissions. Upon detecting a failure, the device may increase the number of the failures represented by the counter (i.e., increment the counter) and maintain the number (i.e., not increment the counter) during the round. The number of failures may increase following consecutive failures in the same round and/or between rounds

- 72 - (e g. , previous/current/upcoming rounds). The value of the counter may be increased or incremented based on the number for discontinuous failures in the same round and/or between rounds. The specific number or value of the counter may be maintained when a new round is initiated after a round is finished. When the number of failed attempts reaches (or exceeds) the threshold of the number of failed attempts, the device may perform the retransmission based on the subsequent access occasions for retransmission in this round (i.e., the same round).

[0114] In some examples, a device may receive a threshold (i.e., information indicating a threshold) of the number of failed attempts and number of round(s) (e.g., specific the previous round and/or number of previous consecutive rounds). When the number of failed attempts is above the threshold number of failed attempts during the number of previous rounds, the device may perform the retransmission based on the subsequent access occasions for retransmission in this round (i.e., the same round).

[0115] In some examples, a device may reset a counter upon receiving the reset request from a reader.

[0116] The device may determine whether to perform the retransmission based on a priority value. In some examples, a device may be configured with a priority value. For example, the priority may be configured by (a part of) device ID and/or category and/or (pre-)configuration in this round. In other words, the device may be configured with a priority value that corresponds to or is mapped to a device ID and/or category and/or (i.e., device ID is pre-configured with a priority value) in the same round. The device may receive or be configured with a different priority values in each round. The priority value may be determined in a semi-static way and/or dynamic way in each round.

[0117] In some examples, each of the priority values of the device may be configured by an upper layer of the device (e.g., NAS layer/application layer). The device may receive a condition (i.e., information indicating a condition for determining whether to perform retransmission or not) with a threshold for a priority value (e.g., 1 to N) For example, when the current priority value of the device is below than the configured threshold (i.e., high priority), the device may perform the retransmission based on the subsequent access occasions for retransmission in this round. In contrast, when the current priority value of the device is above than the configured threshold (i.e., low priority) the device may not perform the retransmission based on the subsequent access occasions for retransmission in this round.

[0118] The device may determine whether to perform the retransmission based on a DL-RSRP value. In some examples, a device may receive a threshold value associated with a DL-RSRP of DL signal, which may be transmitted by a reader. The DL signal may be associated/configured as or more DL signals, e.g., a reference signal, SIB, backscattering signal, SSB. When the measured DL-RSRP value of DL signal is above (or below) than the threshold of DL-signal, the device may perform the retransmission based on the subsequent access occasions for retransmission in this round.

[0119] The device may determine whether to perform the retransmission based on a period of time since the last access. In some examples, a device may be configured with a threshold time since the last successful access by the device. For example, this may be an absolute amount of time. Alternatively, or additionally, this may represent a number of rounds since the last successful access. Alternatively, or additionally, this may represent a number of message receptions from a reader since the last successful access. If the time since the last access is above a threshold, the device may initiate a retransmission procedure.

[0120] Combinations of any the above factors are also possible. For example, the device may determine whether to perform the retransmission based on one or another condition being satisfied, based on multiple conditions being satisfied, based on a threshold for one condition being computed by another factor, etc.

[0121] Device ID(s) for retransmission are described herein. A device may determine whether to perform retransmission or not in the same round based on the one or more device IDs when retransmission is necessary.

[0122] In some examples, a device may receive one or more IDs via broadcast or unicast message. For example, the reader may include the one or more IDs within a broadcast message. This may be, for example, a round initiated message, A Query message, QueryAdjust message, an RRC message, a paging message, a random access response, or another logically equivalent message. The reader may include the one or more configurations for conditions within a unicast message (e.g., RRC reconfiguration message).

[0123] In some examples, a device may receive one or more IDs as a condition whether to perform retransmission or not. The device may determine whether to perform retransmission or not upon receiving the device IDs from the reader. If the device ID (i.e., the device’s device ID) matches the received device ID or if the device ID (i.e., the device’s device ID) is included in the list of device IDs, then the device may determine to perform retransmission in this round. For example, the device may determine whether to perform the retransmission based on the inclusion of one or more device IDs as described in the following paragraphs.

[0124] In some examples, a device may receive a list of device IDs from the reader. The reader may transmit a list of device IDs corresponding to devices over which other devices (e.g., high priority devices) need to be prioritized and allowed to perform retransmission in this round. The high priority devices and associated device IDs may be selected by a reader during the rounds. For example, the reader may select devices from which the reader did not receive responses with corresponding device IDs from during the previous round and/or specific previous round and/or one or more previous rounds and/or the number of previous rounds.

[0125] The device may receive a list of device IDs from the reader. The reader may transmit a list of device IDs corresponding to devices that are prioritized over other devices to allow the retransmission. For example, high priority devices may include one or more devices of a specific inventory category from which the reader may not have received responses with corresponding device IDs during the previous round and/or specific previous rounds and/or one or more previous rounds and/or the number of previous rounds.

[0126] The device may receive a list of device IDs from the reader. The reader may transmit s list of device IDs that are prioritized over other devices to allow the retransmission. For example, a reader may find (or receive, or discover, or obtain) a list of device IDs during an inventory procedure. For example, the reader may need to read the list of device IDs when the reader receives a request to find (or obtain) a list of device IDs from a core network. For example, the reader may receive (i.e., receive information or messages) to find (or receive, or discover, or obtain) a list of device IDs from the upper layer (e.g., application layer, service layer, NAS layer).

[0127] The device may receive a list of device IDs with high priority from the reader. For example, high priority devices may include one or more devices associated with the geographic locations (e.g., zones, areas, cells) from which the reader may not have received responses with corresponding device IDs during the previous round and/or during specific previous rounds and/or a number of previous rounds. When the devices are stationary, the reader may not receive one or more responses from a device located far from the reader. When the devices are mobile, the reader may not receive one or more responses from the one or more devices due to mobility.

[0128] The one or more device IDs may be provided as a subgroup ID. In some examples, a device may be configured with a subgroup ID. For example, the subgroup may be configured by device IDs and/or a category and/or (pre-)configuration. For example, the subgroup ID (or subgrouping) may be configured by upper layers based on a service/application For example, the subgroup may be configured via core network signaling and deliver the configuration of the subgrouping to the reader. In some examples, a reader may receive a paging message for the subgroup ID (e.g , subgrouping devices) from a core network.

[0129] The reader may transmit a subgroup ID that is prioritized over other devices to allow the retransmission. For example, high priority devices may include one or more devices associated with the subgroup from which the reader may not have received responses with corresponding device IDs during the previous round, during a specific previous round, one or more previous rounds, and/or a number of previous rounds. If the configured subgroup ID (i.e., the configured subgroup ID configured at a device) matches the received subgroup ID, then the device may determine to perform retransmission in this round (e.g., the same round).

[0130] The one or more device IDs may be provided as a paged device ID (or paged IDs). In some examples, a reader may receive a paging message from the core network. The device will be paged by the reader. The paging message may include the paged device ID for which the reader may have received a paged device ID. The paged device may have a high priority because the core network may need to establish a connection setup with the paged device immediately. The reader may transmit the paged device ID for the device that is prioritized over other devices to allow the retransmission. If the device ID matches the received paged device ID, then the device may determine to perform retransmission in this round.

[0131] The one or more device IDs may be provided as a session identifier of the devices (or associated with one or more device). For example, one session may be (pre-)configured to (i.e , configured or preconfigured) at a device before a round. In one example, a device may receive a session identifier (e.g., S0/S1/S2/S3) The session identifier corroborates the session number for the round. If the session identifier corresponding to or associated with the device ID matches the received session identifier, then the device may determine to perform retransmission in this round. [0132] Device behavior upon failure of initial transmission is described herein A device may determine to preform retransmission upon detecting a failure of initial transmission in the same round.

[0133] In some examples, a device may detect a collision (e.g., another device has also transmitted in the same access occasion) while performing random access procedure. For example, the device may select one access occasion and transmit a device ID (e.g , a 16-bit RN) in the selected access occasion to a reader. The device may receive a response from the reader. If the device receives a device ID in the response that is not equal to the transmitted device ID (e g., the received device ID is for another device), the device may detect that the access attempt has failed due to a collision (or transmission by another device). The device may assume that another device transmitted its device ID in the same access occasion and delivered successfully to the reader in the selected access occasion.

[0134] In some examples, a device may select one access occasion and transmit UL data (e.g., an indication/MAC CE/RRC message) in the selected access occasion. If the device receives a NACK from a reader, then the device may assume that the UL data transmission has failed. The reader may receive the UL data, but the reader may have failed to decode the received UL data.

[0135] In some examples, a device may select one access occasion and transmit a device ID (e.g., 16-bit RN) in the selected access occasion. If the device does not receive a response from a reader that includes the transmitted device ID, then the device may assume that the access attempt has failed. The reader may not receive the transmitted device ID due to one or more of the following reasons. An example of one reason may be that an interference level is high (e.g., detecting signal ratio is low). For example, a transmitting power from the device may be too low to decode (e.g., small UL coverage). Another example may be that a channel condition (i.e., of a channel between the device and reader) is not good (e g., not of sufficient quality) or does not permit the reader to decode/receive the device ID from the device.

[0136] Methods for selecting access occasions for retransmission are described herein. After detecting a failure of the initial transmission (e.g., collision) and at least one condition for retransmission is satisfied, a device may determine to perform retransmissions in the one or more access occasions.

[0137] In some examples, if none of the conditions (received from a reader) are satisfied, a device may need to wait until a next round without any action. The device may perform an initial transmission upon receiving a message for initiating a new round (e.g., query message).

[0138] In some examples, upon determining to perform retransmission, a device may select one or more access occasions and/or frequencies (e.g., subband) for retransmission based on the access occasion of the previous initial transmission For example, the one or more access occasions (e.g., the access occasions that will be used/selected/transmitted) for retransmission are associated with each of the access occasion used/selected/transmitted for the previous initial transmission in this round (e.g., the association between the one or more access occasions for retransmission and the access occasions for the initial transmission may be semi-statically configured). For example, the association/configuration of each of the access occasion of initial transmission and one or more access occasions may be configured by reader with an initial round message. [0139] FIG. 3 is a diagram illustrating access occasions for initial transmission and retransmission. An exemplary association/configuration of access occasions for initial transmission and retransmission is shown. A total number of access occasions within a round may include access occasions for initial transmission and access occasions for retransmissions. Each of the access occasions for initial transmission may be associated with (or configured) one or more access occasions for retransmissions in the same round.

[0140] In some examples in accordance with the diagram 300 in FIG. 3, when a device performs an initial transmission, the device may select an access occasion within the number of access occasions being configured in this round, e.g., access occasion #1 or access occasion #2. When the device selects access occasion #1 (e.g., using a slot counter), the device may transmit an initial transmission including a device ID in the selected access occasion #1.

[0141] In some examples, access occasion #1 for initial transmission may be associated with one or more access occasions for retransmission. For example, access occasion #1 may be associated with access occasion #17, access occasion #18, access occasion #19, and access occasion #20. If the device failed the initial transmission in the selected access occasion #1 , then the device may select one or more access occasions for retransmission which is associated with the access occasion #1 (e.g., used for initial transmission) based on the association/mapping. To perform the retransmission, the device may select one or access occasions (e.g., access occasion #17 and/or access occasion #18 access occasion #19 and/or access occasion #20) according to the configured association/mapping for access occasion used for the initial transmission (i.e., access occasion #1) in this round.

[0142] In some examples, if the device has failed an initial transmission in the selected access occasion #2, the device may select one or more access occasion access occasions (e.g., access occasion #21 and/or access occasion #22) according to the configured association/mapping for access occasion used for the initial transmission (i.e., access occasion #2) in this round.

[0143] In some examples, a device may determine different ranges (e.g., number of access occasions) of access occasions for retransmission For example, the earlier access occasion may be associated with the time of the last successful transmission (e.g., longer period of time since the last access). For example, the later access occasion may be associated with the duration of the last successful transmission (e.g., a shorter period of time since the last access).

[0144] Retransmission repetitions that are performed based on energy level are described herein A device may determine to perform retransmission using repetitions in the selected one or more access occasions.

[0145] In some examples, a device may receive configuration information indicating a number of access occasions for initial transmission and retransmission in the round. For example, the device may receive configuration information indicating the allowed number of repetitions per each of the access occasions for retransmission.

[0146] In some examples, a device may receive a threshold (e.g., information indicating a threshold) for an energy level for repetition of the retransmissions. For example, when the current energy level of the device is

-7J - higher than the threshold, the device may perform the repeated number of retransmissions based on the allowed number of repetitions per selected each of the access occasions. If the energy level of the device is lower than the threshold, the device may perform retransmission in the selected one or more access occasions without repetition.

[0147] In some examples, a device may receive an indication for a retransmission with repetition from a reader. The reader may send an indication to one or more device types enabling (or disabling) repetition when the device performs retransmission in the selected access occasion in this round. The indication may indicate certain device types, e.g., device type 2a and/or device type 2b. For example, the indication of device type 2a may indicate that the device has an UL transmission with backscattering on a carrier wave provided externally and has its own energy storage. The indication of device type 2b may indicate that the device has UL signal generation capability and has its own energy storage.

[0148] Solutions for power boosting with (or based on) device type is described herein. A device may determine to perform retransmission in the selected one or more access occasions with boosted power.

[0149] In some examples, a device may receive an indication from a reader for transmission power boosting. The reader may indicate to one or more devices to increase UL transmission power when the device performs retransmission. The indication may indicate a certain of device types, e.g., device 2a and/or device 2b. The indication may indicate a certain boosted power, e.g., a power offset and/or explicit increased power (e g., dbm/dB).

[0150] In some examples, the device type 2a may indicate that the device has an UL transmission with backscattering on a carrier wave provided externally and has UL and its own energy storage. The device with device type 2a may increase transmission power with power boosting with UL amplification. The device 2a may perform energy harvesting when the energy level of the device is low. For example, the device type 2b may indicate that the device has UL signal generation capability and has own energy storage. The device with device type 2b may increase transmission power with power boosting with UL amplification.

[0151] In some examples, a device may be allowed to perform power boosting, and the device may perform retransmission with boosted transmission power in the selected one or more access occasions.

[0152] Solutions for selective retransmission associated with initial transmission are described herein. The description provided herein may be provided from a reader perspective. For example, the following paragraphs may describe one or more actions that may be performed by a reader. However, it should be understood by those of ordinary skill in the art that actions corresponding to those described in the following paragraphs may be performed by a reader. For example, a message that is transmitted by a reader may be received by a device. [0153] A reader may determine whether a device performs a retransmission in the subsequent access occasions in the same round based on one or more conditions.

[0154] A reader may perform one or more of the following actions. The reader may transmit a first message initiating a query round (e.g., Query message) which may include a threshold number of failed access attempts, a threshold of or associated with an energy level, a list of device IDs (e.g., high priority), the paged device ID, a total number of access occasions in this round, a number of access occasions for initial transmission and a number of access occasions associated with each of the initial transmission access occasion in this round (e.g., a number of access occasions for retransmission), and/or an indication of the number of repetitions per each of the access occasions (e.g., retransmission).

[0155] The reader may receive a device ID within the number of access occasions within initial transmission in this round from a device. The reader may transmit a response the same device ID to the device.

[0156] If the reader receives UL data or a message (e.g., after a successful access attempt) from the device, the reader may assume successful completion of the first access attempt in this round.

[0157] If the reader receives a device ID from within the number of access occasions associated with the initial transmission access occasion in this round (e.g., within the number of access occasions for retransmission), the reader may determine a first access attempt has failed.

[0158] The reader may transmit a response including the same device ID to the device. If the reader receives UL data or a message (e.g., after a successful access attempt) from the device, the reader may assume successful completion of the second access attempt in this round.

[0159] This solution may provide that one or more devices are allowed to perform retransmission within the number of access occasions for retransmission. The reader may provide opportunities for retransmissions and enable one or more devices to successfully attempt access in the same round when the one or more devices need to be prioritized over others.

[0160] Methods for transmitting a configuration (or configuration information) are described herein A reader may transmit a message to device(s) when a new query round (e.g., inventory round) is initiated. The message may contain a configuration (or configuration information) for a RACH procedure with initial transmission and retransmission for device(s) (e g., total number of access occasions) applicable for this round. The configuration may be applicable/valid for this round (e.g., one round) and/or next number of rounds with an indication of rounds (e.g , multiple rounds).

[0161] The device may perform a RACH procedure for initial transmission and/or retransmission based on the selected access occasion.

[0162] In some examples, a reader may transmit a configuration via a broadcast and/or via a unicast message. The reader may transmit the configuration via a broadcast message The message may be, for example, a round initiated message, Query message, QueryAdjust message, QueryRep message, an RRC message, SIB message, paging message, or any other logically equivalent message. The reader may transmit the configuration via a unicast message (e.g., RRC reconfiguration message).

[0163] In some examples, a reader may transmit a configuration for an initial transmission in this round. For example, the configuration includes one or more access occasions (e.g., slot counters) used for initial transmission in this round. [0164] Methods for transmitting configuration information indicating or providing conditions for retransmission are described herein. A reader may transmit configuration information indicating or providing conditions for determining retransmission (e.g., for determining whether, how, or when to perform transmission) to devices within a message. The one or more conditions may be applicable/valid for this round (e.g., one round) and/or a next number of rounds (e.g., an indication of rounds (e.g., multiple rounds) may be provided). The device may perform the retransmission (e.g., due to a failure of initial transmission) in the same round when the one or more conditions are satisfied.

[0165] In some examples, a reader may transmit one or more configurations indicating or providing conditions via a broadcast and/or via a unicast message. The reader may transmit information indicating or providing the one or more conditions via a broadcast message. The message may be, for example, a round initiated message, Query message, QueryAdjust message, QueryRep message, an RRC message, SIB message, paging message, or any other logically equivalent message. The reader may transmit the one or more conditions via a unicast message (e g., RRC reconfiguration message).

[0166] The reader may transmit configuration information for conditions to devices For example, a reader may transmit information indicating or providing a condition (i e., whether to perform retransmission or not) with a threshold for an energy level of the device. For example, a reader may transmit information indicating a threshold of (or associated with) the number of failed attempts and/or transmissions (e.g., access attempts, DL/UL transmissions). In other words, a reader may transmit a number of failed attempts and/or transmission up to the threshold number In some examples, a reader may transmit a threshold of (or associated with) a priority value. For example, the threshold may be configured as (part of) a device ID and/or category ID.

[0167] Methods for transmitting device IDs for retransmission are described herein. In some examples, a reader may transmit one or more IDs as a condition whether to perform retransmission or not. The device may determine whether to perform retransmission or not upon receiving device IDs from the reader. If the device ID matches the received device ID or the device ID is included in the list of device IDs, the reader may transmit device IDs, e.g., a list of device IDs, such as a subgroup device ID, the paged device ID.

[0168] Methods for determining whether failure of initial transmission has occurred are described herein. In some examples, a reader may determine whether a first access attempt has failed (e.g , due to collision). If the reader receives a device ID within the number of access occasions for retransmission that are associated with the initial transmission in this round, the device may determine the first (i e., initial) access attempt is failed. The device ID may be a new device ID and may not be received within the number of access occasions for initial transmission in this round.

[0169] Retransmission repetitions based on an energy level are described herein. A reader may transmit a number of access occasions for initial transmission and retransmission in the round The device may transmit the allowed number of repetitions per each of the access occasions for retransmission

[0170] In some examples, a reader may transmit information indicating a threshold for an energy level for repetition of the retransmissions. For example, when a current energy level of the device is higher than the threshold, the device may perform the repeated number of retransmissions based on the allowed number of repetitions per each of the selected access occasions. If the energy level of the device is lower than the threshold, the device may perform retransmission using the selected one or more access occasions without repetition.

[0171] In some examples, a reader may transmit repetition information (e.g., information indicating a number of repetitions) and an allowed device type information (e.g., information indicating device 2a and/or device 2b). For example, upon receiving the repetition information and allowed device type information, the device may transmit the repetition based on the repetition information if the device type (e.g , type 2a and/or 2b) matches the received allowed device type.

[0172] Methods for power boosting based on a device type are described herein. A reader may transmit an indication for transmission power boosting to one or more devices. The reader may indicate a device type of devices to increase UL transmission power while performing retransmission. The indication of the device type may indicate, e.g., device 2a and/or device 2b.

[0173] In some examples, the device type 2a may indicate that a device has (or is capable of) UL transmission with backscattering on a carrier wave provided externally and may indicate that the device has its own energy storage. A device of device type 2a may increase transmission power with power boosting with UL amplification. The device 2a may perform energy harvesting when the energy level of the device is low. In some examples, the device type 2b may indicate that a device has UL signal generation capability and its own energy storage. The device of device type 2b may increase transmission power with power boosting with UL amplification.

[0174] A description of examples solutions is provided herein. Some solutions in particular may provide for selective retransmission associated with an initial transmission.

[0175] In some solutions, a device receives a first message initiating a query round (e.g., Query message) which may include a threshold number of failed access attempts, a threshold of energy level, a list of device IDs (e.g., high priority), the paged device ID, a total number of access occasions in this round, a number of access occasions for initial transmission and a number of access occasions associated with each of the initial transmission access occasions in this round (e.g , for retransmission), and/or indication of the number of repetitions per each of the access occasions (e.g., a number of repetitions for retransmission).

[0176] The device may select a random access occasion within the number of access occasions with initial transmission in this round. The device may perform initial transmission (e.g., device ID) in the selected access occasion.

[0177] If the device receives a response to the transmission with the same device ID in the transmission, the device may assume successful completion of the access attempt in this round. Otherwise (e.g., a collision with the initial transmission is detected), the device may determine whether to perform retransmission in the same round based on one or more following conditions: the number of failed access attempts in previous rounds are above the threshold; the current energy level is below the threshold; the device ID is included in the list of devices associated with this access round; and/or the device ID is the paged device ID in this access round.

[0178] If the device ID matches the paged device ID, the device may select one or more random access occasions within the number of access occasions associated with the initial transmission access occasion used for the initial transmission in this round, determine the number of repetitions for each of the selected one or more access occasions based on the indication of the number of repetitions per each of the access occasions and/or perform retransmissions with the determined number of repetitions in each of the selected one or more access occasions in this round.

[0179] If at least one condition is satisfied (e g., a condition other than device ID being the paged device ID), the device may select one or more random access occasions within the number of access occasions associated with the initial transmission access occasion used for the initial transmission in this round. The device may perform retransmissions in the one or more selected access occasions in this round.

[0180] Otherwise (e.g., none of conditions are satisfied), the device may wait for a next query round.

[0181] FIG. 4 is a diagram illustrating an example of selective retransmission associated with initial transmission. As shown in FIG. 4, at 410, a reader 401 may send an initial round message to one or more devices (e.g., including device 402). The initial round message may contain some configuration information and/or condition(s) for this round (e.g., total number of access occasions for initial transmission and retransmission, association with access occasions for retransmission and each of access occasion for initial transmission, one or more configuration for conditions for retransmission).

[0182] At 420, upon reception of the initial round message, the device 402 may select one access occasion randomly. The device 402 may perform initial UL transmission with device ID (e.g., 16-bit RN) and, at 430, receive a device ID as a response from the reader 401. A device 402 may determine whether to perform retransmission or not. If the received ID is the same ID transmitted by the initial transmission, the device 402 may assume that access attempt for the selected access occasion is successful and the device 402 may perform UL data for the following step.

[0183] If the received device ID is not the same as the device ID which was transmitted in the initial transmission, the device 402 may determine to perform retransmission based on the received one or more conditions. If at least one of the received conditions is satisfied, then the device may perform the retransmission, as shown at 440. Upon determining the retransmission, the device 402 may determine one or more access occasions for retransmission associated with the access occasion of the previous initial transmission in this round. The one or more access occasions for retransmission may be associated with each of the access occasions of the initial transmission. At 450, the device 402 may perform one or more retransmissions in one or more access occasions associated with access occasions of the initial transmission

[0184] FIG. 5 is a flow chart illustrating an example of method performed by a device. As shown in FIG. 5, at 510, the device receives configuration information. At 520, the device selects a random access occasion. At 530, the device transmits an initial access transmission in the selected random access occasion and including an identifier. At 540 and 550, on a condition a message including the identifier is not received, the device determines to perform retransmission of the initial access transmission based on the received configuration information and the device transmits a retransmission in an access occasion associated with the selected random access occasion.

[0185] In some examples, determining to perform retransmission of the initial access transmission includes determining whether a number of previously failed access attempts exceeds a threshold value. In some examples, determining to perform retransmission of the initial access transmission includes determining whether a current energy level is below a threshold. In some examples, determining to perform retransmission of the initial access transmission includes determining whether a paging message has been received. In some examples, determining to perform retransmission of the initial access transmission includes determining whether a list of device identifies has been received. In some examples, the method includes selecting one or more subsequent random access occasions access occasions associated with the selected random access occasion. In some examples, the device identifier is a 16-bit random number or a pseudo-random number. In some examples, the method further includes repeating the retransmission in another access occasion associated with the selected random access occasion. In some examples, the retransmission is repeated up to a configured maximum number of repetitions. In some examples, the received configuration information includes one or more of a threshold number of failed access attempts; a threshold energy level, a list of device identifies; a paged device ID; or an indication of access occasions associated with the selected random access occasion.

[0186] In some examples, the device is a wireless transmit/receive unit (WTRU). In some examples, the device is an ambient Internet of Things (AloT) device.

[0187] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer-readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magnetooptical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.

Claims

CLAIMS What is Claimed:

1. A method for accessing a wireless medium, the method comprising: receiving configuration information; selecting a random access occasion; transmitting an initial access transmission in the selected random access occasion, wherein the initial access transmission includes an identifier; determining that a message including the identifier has not been received; based on the determination that a message including the identifier has not been received, determining to retransmit the initial access transmission based on the received configuration information; and transmitting a retransmission in an access occasion associated with the selected random access occasion.

2. The method of claim 1 , wherein the configuration information includes information indicating one or more conditions for retransmitting the initial access transmission

3. The method of claim 1 , wherein determining to retransmit the initial access transmission includes determining whether a number of previously failed access attempts exceeds a threshold value.

4. The method of claim 1, wherein determining to retransmit the initial access transmission includes determining whether a current energy level is below a threshold.

5. The method of claim 1, wherein determining to retransmit the initial access transmission includes determining whether a paging message has been received.

6. The method of claim 1, wherein determining to retransmit the initial access transmission includes determining whether a list of device identifies has been received.

7. The method of claim 1, further comprising selecting one or more subsequent random access occasions associated with the selected random access occasion

8. The method of claim 1 , wherein the device identifier is a 16-bit random number or pseudorandom number.

9. The method of claim 1, further comprising repeating the retransmission in another access occasion associated with the selected random access occasion.

10. The method of claim 9, wherein retransmission is repeated up to a configured maximum number of repetitions.

11. A device for accessing a wireless medium, the device comprising: a processor; and a transceiver; the processor and the transceiver configured to receive configuration information; the processor configured to select a random access occasion; the processor and the transceiver configured to transmit an initial access transmission in the selected random access occasion, wherein the initial access transmission includes an identifier; the processor configured to determine that a message including the identifier has not been received; the processor configured to, based on the determination that a message including the identifier has not been received, determine to retransmit the initial access transmission based on the received configuration information; and the processor and the transceiver configured to transmit a retransmission in an access occasion associated with the selected random access occasion.

12. The device of claim 11 , wherein the configuration information includes information indicating one or more conditions for retransmitting the initial access transmission

13. The device of claim 11 , the processor configured to determine to retransmit the initial access transmission by determining whether a number of previously failed access attempts exceeds a threshold value.

14. The device of claim 11 , the processor configured to determine to retransmit the initial access transmission by determining whether a current energy level is below a threshold.

15. The device of claim 11 , the processor configured to determine to determine retransmit the initial access transmission by determining whether a paging message has been received.

16. The device of claim 11 , the processor configured to determine to retransmit the initial access transmission by determining whether a list of device identifies has been received

17. The device of claim 11 , the processor configured to determine to select one or more subsequent random access occasions access occasions associated with the selected random access occasion

18. The device of claim 11 , wherein the device identifier is a 16-bit random number or pseudorandom number.

19. The device of claim 11 , the processor and the transceiver configured to repeat the retransmission in another access occasion associated with the selected random access occasion.

20. The device of claim 19, wherein the retransmission is repeated up to a configured maximum number of repetitions.