Link adaptation for ambient internet of things (IOT)

Abstract

A reader device transmits a first preamble to a target device including a first preamble including a first calibration signal. The reader device transmits to the target device a control message. In an example, the control message includes information associated one or more random access occasions from a group of random access occasions. The target device transmits to the reader device a first message in a first sub-occasion of a random access of the one or more random access occasions. The reader device transmits a confirmation message including an identity (ID) of the target device and one or both of a link frequency or a sub-occasion index. The reader transmits a second preamble including a second calibration signal. The reader device receives a second message using one or both of a second sub-occasion indicated by the sub-occasion index or the link frequency.

Description

LINK ADAPTATION FOR AMBIENT INTERNET OF THINGS (IOT)CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of U.S Provisional Application No. 64 / 918,904, filed April 1, 2024, the contents of which are incorporated herein by reference.BACKGROUND

[0002] Internet of Things (loT) systems are systems comprising devices having very low power consumption, for example, a range from about 1 W to a few hundreds of piWs. An example of such system is a radio frequency identification (RFID) system, which comprises RFID devices. There may be two types of RFID devices, for example, tags and readers. RFID systems may be used to support various loT applications such as inventory control, containers tracking, and patient monitoring, among others. As an example, in an inventory control procedure, an interrogator may send a query message to energize all tags or a subset of tags. Following the query message, the tag may perform a random access procedure and may initiate a contention resolution procedure The contention resolution procedure includes of transmitting the tag device identity (ID) in the uplink and waiting for a confirmation of the reception of the tag device ID, which is sent in the downlink. For a tag that has passed contention resolution, the reader may send multiple read / write commands, to which the tag should respond. In this model, the same symbol duration (data rate) and chip rate are used by all devices in an inventory round.SUMMARY

[0003] Radio frequency identification (RFID) systems are Internet of Things (loT) systems comprising two types of devices, referred to as tags and readers RFID devices have at least one antenna that is used by the device to communicate with each other using signals. Different applications may take advantage of an RFID system such as inventory control, containers tracking, patient monitoring, pet finding, and children tracking, to name a few.

[0004] As an example, in an inventory control system, a reader device, also referred to as an interrogator device, may trigger multiple tag devices using a sequence of messages, to which the tag devices may respond to. In other words, the inventory procedure may comprise a single round of attempts of having each tag device respond or attempt to respond with its access identity (ID) or perform a random access procedure.

[0005] To trigger a tag device, a reader device may use a paging procedure. In one example, a paging message may identify the tag device via the device ID Several tag devices may be identified in the paging message. Optionally, devices may belong to groups and group IDs may be identified in the paging message. Additionally or alternatively, the reader device transmits a first preamble including a first calibration signal to the tag device. Additionally or alternatively, the reader device transmits a control message, including one or more random access occasions from a group of random access occasions.

[0006] In response to receiving a paging message addressed to a tag device, the tag device may perform an access procedure. During the access procedure, the tag device may select an access occasion. In one example, a tag device may select an access occasion randomly. In another example, the tag device may select an access occasion based on the tag device ID, part of the tag device ID, or a function of the tag device ID. In one example, the tag device ID may be an ID generated randomly.

[0007] Further, the reader device may receive a first message in a first sub-occasion of a random access occasion of the one or more random access occasions. In an example, the reader device is a first WTRU. Additionally or alternatively, the tag device is a second WTRU.

[0008] After a successful access procedure, the communication is established and the tag and reader devices may transmit to and receive from each other. To optimize the communication, the reader device may provide configuration parameters to the tag device for a subsequent transmission by the tag device. In one example, the reader device may provide the configuration parameters at the end of a successful access procedure, such as in a final confirmation message from the reader device to the tag device. The configuration parameters may include, for example, one or more of a symbol duration, a link frequency, a chip rate, or a suboccasion index. Additionally or alternatively, the confirmation message includes an ID of the tag device. The tag device may utilize the configuration information received at the end of the access procedure to send a subsequent message to the reader device.

[0009] Additionally or alternatively, the reader device transmits a second preamble including a second calibration signal to the tag device. The reader device receives a second message from the tag devices using one or both of the sub-occasion index or the link frequency.BRIEF DESCRIPTION OF THE DRAWINGS

[0010] 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:

[0011] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0012] 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;

[0013] 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;

[0014] 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;

[0015] FIG. 2 shows an example of subcarrier modulation;

[0016] FIG. 3 shows a call flow of an example of an inventory procedure from RFID;

[0017] FIG. 4 illustrates an example flow chart for a paging procedure using a conditional paging;

[0018] FIG. 5 illustrates a Manchester encoding example;

[0019] FIG. 6 illustrates Manchester encoding with M = 4 symbols;

[0020] FIG. 7 shows an example of a calibration signal;

[0021] FIG. 8 illustrates an example call flow for the establishment of the communication between the reader device and the target device (for example, tag); and

[0022] FIG. 9 shows an example flow chart for a reader device for the establishment of communication with another device.DETAILED DESCRIPTION

[0023] 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, and so forth, 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), single-carrier 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.

[0024] 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 (ON) 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 / orcommunicate 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-Fi 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 (for example, remote surgery), an industrial device and applications (for example, 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.

[0025] 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.

[0026] 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.

[0027] 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 (for example, radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, and so forth). The air interface 116 may be established using any suitable radio access technology (RAT).

[0028] 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).

[0029] 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).

[0030] 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.

[0031] 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 (for example, an eNB and a gNB)

[0032] 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.

[0033] 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 (for example, 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 (for example, WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR and so forth) 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.

[0034] 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, and so forth, 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.

[0035] 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.

[0036] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (for example, 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.

[0037] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG. 1B, 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.

[0038] 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.

[0039] The transmit / receive element 122 may be configured to transmit signals to, or receive signals from, a base station (for example, 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.

[0040] Although the transmit / receive element 122 is depicted in FIG. 1B 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 (for example, multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[0041] 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.

[0042] 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 (for example, 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 nonremovable 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).

[0043] 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 moredry cell batteries (for example, nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium- ion (Li-ion), and so forth), solar cells, fuel cells, and the like.

[0044] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (for example, 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 (for example, 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 locationdetermination method while remaining consistent with an embodiment.

[0045] 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.

[0046] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (for example, associated with particular subframes for both the U L (for example, for transmission) and DL (for example, 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 (for example, a choke) or signal processing via a processor (for example, 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 (for example, associated with particular subframes for either the UL (for example, for transmission) or the DL (for example, for reception)).

[0047] 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 CN 106.

[0048] 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 MIMOtechnology. 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.

[0049] 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.

[0050] 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.

[0051] 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

[0052] 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.

[0053] 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.

[0054] 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 (for example, 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.

[0055] 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 (for example, temporarily or permanently) wired communication interfaces with the communication network.

[0056] In representative embodiments, the other network 112 may be a WLAN.

[0057] 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 (for example, 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 (I BSS) mode may not have an AP, and the STAs (for example, 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.

[0058] 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 (for example, 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 (for example, 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 (for example, only one station) may transmit at any given time in a given BSS

[0059] 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.

[0060] 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).

[0061] 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 (for example, only support for) certain and / or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (for example, to maintain a very long battery life).

[0062] 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 (for example, MTC type devices) that support (for example, 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.

[0063] 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 802.11 ah is 6 MHz to 26 MHz depending on the country code.

[0064] 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.

[0065] 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 theWTRU 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).

[0066] 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 (for example, containing a varying number of OFDM symbols and / or lasting varying lengths of absolute time).

[0067] 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 (for example, 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.

[0068] 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.

[0069] 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.

[0070] 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 (for example, handling ofdifferent 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.

[0071] 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.

[0072] 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.

[0073] The CN 106 may facilitate communications with other networks For example, the CN 106 may include, or may communicate with, an IP gateway (for example, 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.

[0074] 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.

[0075] 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.

[0076] 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 (for example, 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 (for example, which may include one or more antennas) may be used by the emulation devices to transmit and / or receive data.

[0077] Internet of Things (loT) devices may be characterized as devices that have power consumption range from about 1 W to a few hundreds of piWs. Radio frequency identification (RFID) systems are loT systems which comprise two types of devices, referred to as tags and readers. RFID devices have at least one antenna that is used by the device to communicate with each other using signals. Different applications may take advantage of an RFID system such as inventory control, containers tracking, patient monitoring, pet finding, and children tracking, to name a few.

[0078] loT devices may transmit using backscattering. A backscatter device reflects an incoming RF signal and may not need to generate its own RF signal. The backscatter device may also modulate an incoming RF signal Sin(t) to transmit its own data on the reflected signal This may be achieved by using the impedance mismatch concept. An antenna impedance may be connected to a load impedance at the device. By changing the reflection coefficient (for example, by adjusting the load impedance) over time, the amplitude, frequency, and so forth of the reflected signal may be changed. For example, Amplitude Shift Keying (ASK) modulation may be achieved by using non-reflecting state / OFF signal or reflecting state / ON signal. An RFID specification is generally based on backscatter communications, wherein RFID tags switch the reflection coefficient between two states based on the data being sent. ASK and Phase Shift Keying (PSK) may be supported by the RFID tags.

[0079] Information bits may be mapped to physical signals (for example, voltage levels) using a line code. In RFID, pulse interval encoding (PIE) may be used in the reader-to-tag direction. In the tag-to-reader direction, FM0 or Miller encoding may be used. Subcarrier modulation may be used for Miller encoding. In subcarrier modulation (spreading), Miller symbols are multiplied by a subcarrier signal (a square wave) to generate the transmitted signal.

[0080] FIG. 2 shows an example of subcarrier modulation. In the example in FIG. 2, Ts denotes the symbol period and Tc denotes the chip period. The spread signal is then modulated on a carrier wave using a modulation scheme such as ASK or PSK.

[0081] RFID is currently used for applications of asset identification. An inventory procedure may be used for RFID systems.

[0082] FIG. 3 shows a call flow of an example of an inventory procedure from RFID. In the inventory procedure, an interrogator 380 sends a Query message to energize all or a subset of TAGs, such as TAG 340. Following a Query message, the TAG 340 selects a random number from 0-2AQ-1 and loads its memory with that number. At each transmission of a QueryRep, the TAG 340 decrements its counter until the counter reaches 0. When the counter reaches 0, the TAG 340 initiates a contention resolution procedure which consists of transmitting its device ID in the uplink and waiting for confirmation of the device ID in the downlink (to address possible collision between multiple devices selecting the same random number). For a device that has passed contention resolution, the interrogator 380 can send multiple read / write commands, to which the TAG 340 should respond.

[0083] Current procedures result in problems and inefficiencies in wireless communications. Specifically, if the same symbol duration (data rate) and chip rate is used by all devices in an inventory round, system efficiency is not optimized because the difference in channel quality of the devices is not used for link adaptation and the frequency spectrum is underutilized This may degrade the system efficiency more significantly when a device is transmitting to a reader since the payload size may be hundreds of bits. Accordingly, the fact that the channel quality is not used for link adaptation may result in underutilization of the frequency spectrum and may degrade the system efficiency.

[0084] Embodiments and examples of solutions are provided herein In an example system, one or more devices may choose randomly a time / frequency resource for the initial transmission (for example, a random device ID) and their link is adapted for the subsequent data transmission (for example, transmission of product code t, sensor data , and so forth).

[0085] An example of actions or a reader device, or a WTRU, includes one or more of the following actions, which may be ordered in different combinations. For example, a reader (for example, a WTRU) may be configure to transmit a preamble wherein the preamble may contain a signal representing one or more symbols / bits (for example, bitO, bit 1) and at least one calibration signal. Additionally or alternatively, the WTRU may transmit a control message (for example, in a Reader-to-Device channel), wherein the control message may contain one or more of the following. The control message may contain a parameter to indicate the number of random access occasions (for example, Q, number of access occasions = 2^).

[0086] Additionally or alternatively, the control message may contain a signaling to indicate one or more of the Device-to-Reader link frequency or frequencies (chip duration), symbol duration (data rate) associated with each access occasion in a group of access occasions. For example, the signaling may indicate bitmap to F linkfrequencies for each access occasion in a group of access occasions (for example, F may be the same for each access occasion). For example, the signaling may indicate bitmap to Fi link frequencies for each access occasion i in a group of access occasions

[0087] Additionally or alternatively, the control message may contain signaling to enable / disable (for example, 1 enables, 0 disables; or vice versa) determination of one or more random access occasions and / or the associated link frequency based on bits from the device ID (for example, random ID). For example, when enabled, the first Q most significant bits (MSBs) of the device ID determines a time occasion and the next F (or Fi) MSBs determines a link frequency.

[0088] Additionally or alternatively, the WTRU may receive transmission in an access occasion in each of one or more of the link frequencies indicated for the access occasion (for example, where each received transmission contains a random device ID).

[0089] If at least one device ID is successfully detected, the WTRU may perform one or more of the following for each of the successfully detected device IDs, additionally or alternatively.

[0090] The WTRU may transmit a confirmation message wherein the confirmation message may include one or more of the following: the device I D (or part of the device I D); or one or more parameters for a subsequent transmission by the device, for example, a symbol duration, a link frequency, a chip rate (for example, for square wave frequency shifting), and / or a sub-occasion index.

[0091] The WTRU may transmit to the device a Device-to-Reader calibration signal to be used for the subsequent transmission.

[0092] Additionally or alternatively, the WTRU may transmit an indication in an access occasion that indicates when the sub-occasion corresponding to the sub-occasion index starts. Additionally or alternatively, the WTRU may receive data within the sub-occasion from a device scheduled for the sub-occasion using the associated parameters (for example, BLF, chip rate, and so forth).

[0093] In a further example, a device (for example, a WTRU) may receive a preamble wherein the preamble may contain a signal representing one or more symbols / bits (for example, bit O, bit1) and at least one calibration signal. In an example, the device may be an Ambient loT (AloT) device.

[0094] Additionally or alternatively, the device may receive a control message (for example, in a Reader- to-Device channel) wherein the control message may contain one or more of the following. The control message may contain a parameter to indicate the number of random access occasions (for example, Q, number of access occasions = 2^). Additionally or alternatively, the control message may contain a signaling to indicate one or more of the Device-to-Reader link frequency or frequencies (chip duration), symbol duration (data rate) associated with each access occasion in a group of access occasions. For example, the signaling may indicate bitmap to F link frequencies for each access occasion in a group of access occasions (for example, F may be the same for each access occasion) For example, the signaling may indicate bitmap to Fi link frequencies for each access occasion i in a group of access occasions.

[0095] Additionally or alternatively, the control message may contain signaling to enable / disable (for example, 1 enables, 0 disables; or vice versa) determination of random access occasion and / or the associated link frequency based on bits from the device ID (for example, random ID). For example, when enabled, the first Q MSBs of the device ID determines a time occasion and the next F (or Fi) MSBs determines a link frequency.

[0096] If determination of random access occasion and / or the associated link frequency based on bits from the device ID is enabled, then the device determines an access occasion and a link frequency based on the randomly generated device ID. Else, the device determines randomly an access occasion and a link frequency.

[0097] Additionally or alternatively, the device may transmit an initial message. Additionally or alternatively, the device may receive a confirmation message wherein the confirmation message may include one or more of the following: the device ID (or part of the device ID); one or more parameters for a subsequent transmission by the device, for example, a symbol duration, a link frequency, a chip rate (for example, for square wave frequency shifting), and / or a sub-occasion index.

[0098] Additionally or alternatively, the device may receive a calibration signal associated with the link frequency indicated in the confirmation message. Additionally or alternatively, the device may receive an indication in an access occasion that indicates when the sub-occasion corresponding to the sub-occasion index starts. Additionally or alternatively, the device may transmit data within the sub-occasion using the associated parameters (for example, BLF, chip rate, and so forth).

[0099] Embodiments and examples in the following include further solutions Further, embodiments and examples herein may use the following common terminology.

[0100] For example, embodiments and examples herein may use the following device terminology. The terms device, loT device, AIOT UE, AIOT WTRU, and TAG are used interchangeably to mean the AIOT device that is being inventoried / queried by the reader.

[0101] The term reader refers to the entity which queries the AIOT device, either directly, or via an intermediate UE or WTRU. The term reader may also refer to the intermediate UE or WTRU. As a result, the term reader may refer to a network node or a UE or WTRU, depending on the context and / or the topology The terms reader, network, intermediate UE, or intermediate WTRU may be used interchangeably to represent the reader.

[0102] Also, embodiments and examples herein may use the following inventory terminology. Herein, inventory may refer to the overall procedure of a reader triggering access by multiple devices using a sequence of messages (for example, similar to query, followed by query rep in RFID). Specifically, the inventory procedure refers to a single round of attempts to have each device respond or attempt to respond with its access ID or perform a random access channel (RACH) procedure. Specifically, the inventory procedure refers to a set of access occasions which may have 0 or at least 1 device respond within the access occasion.

[0103] Moreover, embodiments and examples herein may use messages with specific names exchanged between devices. One of ordinary skill in the art will understand that the embodiments and examples herein still apply if other names are used by those message. For example, a Query message may be referred to as a paging message and the embodiments and examples herein will still apply. Further, a QueryRep message may be referred to as a RACH trigger message, and the embodiments and examples herein will still apply. Also, embodiments and examples herein may use the term occasions but those embodiments and examples will apply to sub-occasions as well. For example, the reader with scheduling information may indicate an occasion and / or a sub-occasion within an occasion.

[0104] An inventory procedure may occur similarly to a legacy RFID procedure. Although referred to as an inventory procedure, it may be termed differently in device requirements or specifications (for example, query procedure, paging procedure, and so forth).

[0105] Occasion may refer to the opportunity for device transmission that may be delimited by the transmission of a query rep message (or similar). Specifically, a device may perform transmission in an occasion by performing a AIOT transmission in a defined time following the QueryRep associated with that transmission. QueryRep may refer to an indication used to delimit an access occasion

[0106] Depending on the solution or description, a reference to time can be associated with an absolute time measurement (for example, seconds, slots, frames, and so forth), in embodiments and examples herein. Additionally or alternatively, a reference to time can refer to a number of executions of a procedure, possibly triggered by a reader (for example, number of inventory procedures, number of accesses or RACH procedures, and so forth). Additionally or alternatively, a reference to time can refer to a number of messages, possibly of a specific type, or containing specific information, as described herein, received, or transmitted.

[0107] Common examples solutions for some embodiments are provided in the following herein.

[0108] The paging procedure at the device may consist of receiving, in a message from the reader, an ID or list of IDs for which the subsequent inventory procedure becomes relevant. The paging message can be similar, in terms of sequencing, to the “select” message in RFID. When a device determines that its device ID is included in the paging message, the device may receive and decode the subsequent messages from the reader (for example, similar to query and query rep) in order to receive its RRC configuration.

[0109] The paging procedure may identify a single device, or a finite number of devices. In such case, the paging message (for example, select) or subsequent messages (for example, query) may include a defined mapping of occasion to device. For example, in case of a single device being paged, the reader may configure a single occasion and the access or RACH procedure may be a deterministic procedure.

[0110] Devices may be assigned to groups. One device may be part of one or more groups. The paging message may be a group paging message, for example, addressed to a group of devices using an group identification (ID). When a device determines that the group ID included in the paging message is of a group that the device belongs to, the device may start an access procedure.

[0111] The paging procedure may further identify a subset of devices in terms of condition or state, rather than device ID. For example, the paging procedure may identify (for example, using predefined device ID, or using an explicit indication included in the paging message) and one of or any combination of the following.

[0112] The paging procedure may identify all devices that were not able to access or provide their information (i.e., failed inventory) in the past (for example, the last inventory round, the last x inventory rounds, and so forth).

[0113] The paging procedure may identify all devices that have data available to transmit to the reader. For instance, devices that have at least a certain amount of data, as indicated in the paging message may be identified For instance, devices that have at most a certain amount of data, as indicated in the paging message may be identified. For instance, devices that have a certain type of data (for example, data with a specific QoS, data with a specific time sensitivity, data that needs to be transmitted within a certain time, and so forth), as indicated in the paging message may be identified.

[0114] The paging procedure may identify all devices that are located in a specific area, as indicated in the paging message.

[0115] The paging procedure may identify all devices that have a specific capability or are of a specific device type, as indicated in the paging message.

[0116] The paging procedure may identify all devices that have not yet reported their identity (device ID), possibly to a specific reader which may be identified in the paging message.

[0117] The paging procedure may identify all devices that have experienced a failure (for example, have not performed access in a past inventory procedure) due to inability to comply with a configuration.

[0118] The condition may be encoded in a format that the devices can understand when receiving the paging message. As an example, code “1” may represent a paging message to all devices with failed inventory; code “2” may represent a paging message to all device that have data to send to the reader; code “3” may represent all devices that have at least a certain amount of data to send to the reader, where the amount of data may also be indicated in the paging message or may be pre-configure with the code “3”, and so on, based on the conditions. The device may be pre-provisioned or pre-configured with the information associated with the encoding of the conditions

[0119] In one example, the condition may be part of the paging signal itself, for example, a condition may be associated with a known paging signal; if there are N possible conditions, then N different paging signals may be defined. The device may listen only to the paging signal which is associate with the device’s condition during the time the paging is being received. If the device’s condition changes, the device may start listening to the paging signal associated with the new condition.

[0120] Many other methods may be envisioned to provide the condition in the paging message and for the reader to identify the condition associated paging message. Above are only some non-limiting examples.

[0121] FIG. 4 illustrates an example flow chart for a paging procedure using a conditional paging. As shown in FIG. 4, upon receiving a paging message 410 from a reader, a target device (Tag) 440 may extract the encoded condition and verify if the device satisfies the condition that is included in the paging message received. In this way, the target device may determine a condition from the paging message 430. In one example, more than one conditions may be included in a paging message.

[0122] The target device evaluates whether the condition is met 450. If the device satisfies the condition, the target device may start an access procedure 490. In an example, the device may start a random access procedure. Additionally or alternatively, the device may start a deterministic access procedure. Examples of a RACH procedure are provided herein below. As a result, the target device may receive and decode subsequent messages from the reader. If the device fails to satisfy the condition, the device may return to sleep 470.

[0123] Following reception of a paging message, such as shown above, a device which meets such criteria should perform a RACH procedure described below.

[0124] The RACH procedure may be initiated with a device’s first transmission during an occasion. Such transmission may be similar to the transmission by the device in RFID to indicate the device ID. Such transmission may be followed by a confirmation of the ID by the reader. Such transmission may be initiated by the device upon reception of an indication that an occasion has been started. As with RFID, the indication of a start of an occasion may be signaled in a message from the reader (for example, in the query rep message).

[0125] In one example, a device may initiate a RACH procedure only in a specific occasion. Occasions may be delimited by certain transmission by the reader (for example, similar to RFID where each query rep denotes the start of an occasion). The transmission may include an index to an occasion. As an example, an occasion index may start from 0 (or 1 ) to a maximum number (for example, the number of occasions in a round). The transmission may include a message (for example, a 1 -bit message) to indicate the start of an occasion. The transmission may include a signal such as a preamble.

[0126] Additionally or alternatively, a device may initiate a RACH procedure in multiple occasions. Additionally or alternatively, a device may initiate RACH in an occasion indicated by the reader in the paging message, a broadcast configuration message (for example, similar to query, in which case, a mapping is provided from device ID or condition to occasion number) or in any of the occasion delimiting messages (for example, the occasion delimiting message contains a specific device ID or condition for such occasion).

[0127] A device may perform a contention based or contention free RACH procedure. In a contention free RACH procedure, the device may send a different set of information compared to contention-based RACH procedure. In a contention-based RACH procedure, the device may include its device ID. A device may further include configuration related information (for example, a desired configuration, an indication that it can comply with its configuration). In contention-free RACH procedure, the device may include no device ID. Specifically, in the case the initial message which starts the occasion (for example, the query rep 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.

[0128] Contention resolution may, for example, determine whether a device should decode messages (for example, messages indicated as unicast) in a given occasion. Contention resolution may consist of a device receiving a confirmation of the device ID sent in the previous RACH message. 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.

[0129] Additionally or alternatively, 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 messages containing that non-matching device ID, while it may forward all messages containing the matching device ID to the upper layers.

[0130] Data transmission may consist of data exchanges (for example, in unicast messages) that occur within each occasion. A reader may explicitly identify a message as being unicast or groupcast (for example with a flag in a protocol header, or by inclusion of a device ID in a protocol header). A device may treat the reception of unicast data different than broadcast transmissions.

[0131] A link frequency (also referred to as backscatter link frequency) may refer to the center frequency of a baseband signal, for example, a signal as an output of a line coding scheme. A link frequency may be determined by the chip period or chip frequency such as LF = 1 / Tc. A symbol period may be equal to a chip period (Ts = Tc), or a symbol period may contain multiple chip periods (Ts = MTc) where M may be an integer. When subcarrier modulation is not applied, Tc may be equal to Ts. Data rate R may be determined by the symbol period such as R = m(1 / Ts), where m may be referred to as the modulation order and is the number of bits carried in a symbol.

[0132] The reader and the device may be configured, for example, signaled one or multiple tables, to characterize the relationships between possible link frequencies, symbol durations, number of chips, and so forth. In one example, an entry in a table may contain a link frequency, M, modulation type and modulation order. The symbol length may be determined as M*Tc = M*(1 / LF). The data rate may be determined as m*(1 / (M*Tc)) = m*LF / M. If frequency-shift keying (FSK) modulation is used, multiple link frequencies (for example, 2) may be included in an entry. Such tables may be specified, and parts of such tables may be activated (for example, activation may mean that the activated parts may be used to determine transmission parameters) by configuration, by signaling, or by both. For example, K link frequencies may be defined in a system but only N of them may be available to use in an inventory round, where N<K.

[0133] Examples and embodiments including random access with link adaptation are provided herein. In an example, a device receives an indication of a query.

[0134] In one example method, the reader may send at least one indication to a group of devices to initiate a query. The indication may comprise a message and / or a signal. A message may be a paging message. A message may be a control message, a configuration message, or both. A control message may refer to a message that may contain information used to at least control the transmission from a device, reception by a device, or both. For example, a message may contain: information to determine the transmission resources intime, in frequency, or in both; and transmission parameters such as the modulation type, line coding type, data rate, and so forth. A signal may be a preamble, a reference signal, and so forth. In one example, a message may follow a preamble. A preamble may contain a calibration signal. A calibration signal may be used by a device to calibrate its timing

[0135] A control indication may comprise a common message targeting potentially a group of devices or a dedicated message targeting one device. For example, a common control message (for example, a message similar to the Query message in RFID) may contain the number of access occasions or a parameter from which a device can determine the number of access occasions. An access occasion may refer to a time interval during which a device may transmit or be allowed to transmit a message and / or a signal, for example a preamble, an access request message (for example, a random ID), and so forth. A control message may contain parameter(s) from which the frequency resources (for example, at least one link frequency) may be determined by a device

[0136] In one method, the reader may send a control and / or configuration message to indicate an association between access occasions in time and link frequencies such that a receiving device may determine the set of link frequencies in an access occasion. For example, in one or a group of access occasions, a device may be allowed to use link frequencies F1 and F2, and in another access occasion or in a group of access occasions, a device may be allowed to use link frequencies F1 and F3. In one example case, the same set of link frequencies may be usable in all access occasions. The control message may contain a bitmap to indicate the access occasion, including link frequency pairs. For example, if there are n available link frequencies F1 to Fn (for example, specified by a specification and / or configured), an n-bit bitmap may be used to indicate the available link frequencies in an access occasion. For example, the bit in the kth location of the bitmap may indicate the availability of link frequency Fk in a group of access occasions.

[0137] The device may determine, from a control indication, the mechanism used to delimit the access occasions in time. For example, a control indication may be used to determine if a message (for example, a QueryRep) contains an index for the access occasions (for example, from 0 to N).

[0138] In an example, a device determines the set of access occasions. In one example method, a device may determine a set of access occasions based on at least a parameter indicated in a control indication, for example, a Query message

[0139] In one example, a control message may contain a number from which the number of access occasions may be determined. For example, the Query message may contain a parameter Q (for example, Q is an integer) and the device may determine that there are 2^ access occasions in this query and / or that a value for a specific counter (for example, access occasion counter, slot counter, and so forth) may be determined based on the value of Q.

[0140] In one example method, a plurality of group of access occasions may be available to a plurality of access types. Access types may be, for example, random access or scheduled access. In one example, a first- 72 -range of access occasions may be available for an initial access (for example, an access in which a device may transmit an initial signal and / or a message) and a second range of access occasions may be available for an access other than an initial access, (for example, for scheduled transmission to / from a device).

[0141] For example, a Query message may contain a first parameter Q1 and a second parameter Q2 wherein a first parameter may be used to determine the number of access occasions for a first type of access and a second parameter may be used to determine the number of occasions for a second type of access. In another example, the Query message may contain Q and a ratio C wherein QC access occasions may be allocated for a first type of access and the rest may be allocated for a second type of access. The order of the occasions may be predetermined or configured. For example, occasions for random access may come first and occasions for scheduled access may come later.

[0142] In one example method, the reader may continue transmitting or receiving beyond the number of access occasions indicated in a Query message. In one example method, the reader may monitor random access attempts (for example, a random-access message, preamble, and so forth) in a first 2^ access occasions. Upon successfully determining a device, the reader may command the device to transmit and / or receive in an occasion beyond the 2^ access occasions.

[0143] In one example method, more than one query process may run in parallel. Each of such processes may be referred to as a session. The session index may be indicated in one or more of the control indications. For example, the session index may be contained in a Query and in a QueryRep message. In one example method, a first session may be allocated for a first type of access (for example, initial random access) and a second session may be allocated for a second type of access (for example, scheduled access and / or a retransmission). For example, a reader may schedule a device to transmit and / or receive in an access occasion belonging to a specific session.

[0144] Methods to identify a specific access occasion are provided in examples in the following. In one example method, the device may select a random integer between 0 and Q-1 (or 1 and Q) and set a counter, for example, an access counter, to the selected integer. The device my decrement the counter with each access occasion indication (the device may skip decrementing with the first indication). The indication to decrement the counter may be a message, for example, the QueryRep and / or the Query. The access occasion for which the counter becomes 0 may be the access occasion in which the device may attempt access

[0145] In another example method, the device may select a random integer between 0 and Q-1 (or 1 and Q) and set a counter, for example, an access counter, to 0. The device may increment the counter with each access occasion. The device may skip incrementing with the first indication The indication to increment the counter may be a message, for example, the QueryRep and / or the Query. The access occasion for which the counter becomes 0 may be the access occasion in which the device may attempt access.

[0146] The device may select a random integer between 0 and Q-1 (or 1 and Q) and this index may be the index of the access occasion in which the device may attempt access. The access occasion index may be included in a message, for example, the QueryRep and / or the Query.

[0147] An access occasion may have a type associated with it, for example initial access occasion and scheduled access occasion The type may be included in the QueryRep message and / or may be associated with a transmission parameter and / or a signal. For example, the preamble preceding a QueryRep may be associated with the access type of the access occasion indicated by the QueryRep. The device, upon receiving the QueryRep message, may increment or decrement a counter only if the access type of the counter matches the access type indicated in the message. For example, a device attempting initial access may set the counter to a value and decrement or increment the counter with a QueryRep if the access type indicated in the QueryRep is initial access.

[0148] In examples provided herein, a device determines resources and transmission parameters. The parameters to define a transmission from a device to the reader may include one or more of the following: Link frequency (LF); Chip rate and / or chip period (for example, Tc); Number of chips per symbol (M); Line coding scheme (Miller, FMO, Manchester, and so forth); Symbol duration (Ts); Modulation order; Modulation type (for example, ASK, on-off keying (OOK), PSK, FSK, and so forth); or Transmission power and / or signal amplification level.

[0149] Note that these parameters may have certain relationships as presented before (for example, LF = 1 / Tc). A device may determine to use a set of parameters with a first set of associated values in a first access (for example, in random access) and a second set of parameters with a second set of associated values in a second access (for example, in scheduled access).

[0150] A device may determine to use at least a first link frequency and at least a first access occasion to transmit to the reader, for example, for an initial transmission. A device may determine to use at least a second frequency and at least a second access occasion to receive from the reader. In one example, a device may transmit to and receive from the reader in the same access occasion, but the transmission and reception may occur at different frequencies within the access occasion. The determination may be achieved based on one or more of the following.

[0151] Examples provided herein include random selection. In one example method, a device may select an access occasion randomly. In one example method, the device may select an access occasion based on a device ID, part of a device ID, and / or based on a function of a (part of a) device ID. The device ID may be an ID generated randomly. For example, the device ID may be generated randomly and may be sent to the reader as part of an access procedure. The device may use one or more bits from the ID to determine an access occasion. For example, the ID may be a 16-bit number and the device may use the Q MSBs or the Q least significant bits (LSBs) to choose an index which may be set to be equal to the value of the MSBs / LSBs (for example 1000 = 8). The device may set a counter (for example, an access occasion counter or a slot counter) to the randomly selected index. The device may decrement the counter with each received access occasionindication such as a QueryRep and initiate a random access (for example, an initial random access) when the counter hits 0. Additionally or alternatively, the device may set the counter initially to 0 and increment the counter with each received access occasion indication and transmit when the value of the counter hits the randomly selected index. QueryRep may contain an explicit indication of the index of an occasion. For example, the number of occasions may be 2^, and the QueryRep may indicate the occasion index from 0 to 2® — 1. The index may be determined directly from the bits in the ID or as a function of the bits. For example, mod operation may be used. The bits, instead of indicating a specific occasion, may be used to determine a range of access occasions.

[0152] An access occasion may be associated with one or more link frequencies, in an example The device may determine at least one link frequency, for example, randomly from the list of frequencies associated with the access occasion and determined from the control message. Similar to above, bits (directly) or bits as a function from the device ID may be used. For example, next m-MSBs or next m-LSBs may be used to choose from 2m link frequencies. The reader may enable / d isable using the device ID to choose access occasion and / or link frequency. When disabled, the device may choose randomly but not by using the ID. A device may be allocated a specific occasion and frequency.

[0153] The device may first select link frequency and then select access occasions from the set of occasions associated with the link frequency. The selection may be random selection. The device may use bits from the device ID or generate bits by applying a function on the device ID bits. For example, for initial transmission, occasion index may be between 1 -2AQ.

[0154] Examples are provided herein of selection based on a measurement. In one example method, the device may determine to use a set of transmission parameters based on a measurement. As one example, LF may be used as the transmission parameter for selection, but the same methods apply to other parameters, for example, Ts, Tc, and so forth.

[0155] In one example solution, the device may measure, for example, the duration of, at least two signals, such as two calibration symbols. The device may use the measurement results to determine a representative value. In one example with two calibration symbols, the representative value may be determined as v = [ml + k(m2)] / K, k = 0, 2, .. K-1 where ml and m2 are the measurements, k is an integer, and K is an integer that may be predetermined and / or signaled. The same method may be extended to more than two measurements, for example, v = [ml + k1 (m2) + k2(m3)] / K, k1 = 0, 2, .. K1-1; k2 = 0, 2, ... K2-1 , and so forth. A floor operation may be applied to the calculation.

[0156] In one example method, the device may compare each representative value v, to a set of nominal values which may be predetermined and / or signaled. The device may compute an error value (for example, percentage of error between the measured and the nominal value) for each of the nominal values; for example, 6ik=(Vk- Vi) / Vj where Vi may be the i-th nominal value and 6ik is the corresponding error. The device may determine one of the nominal values by using one of the following.

[0157] The device selects the nominal value with the corresponding smallest error. The device finds a set of nominal values with the corresponding error below a threshold and selects randomly a nominal value within the set

[0158] The device may determine the selected nominal value to be the value from which transmission parameters are derived from. For example, the symbol duration Ts may be determined as v multiplied with a predetermined and / or signaled coefficient C, for example, Ts = Cv. The link frequency LF may be determined as (1 / Tc) where Tc = Ts / M.

[0159] The above example method may be similarly used to first determine an error between a parameter derived from v and the nominal values of the parameter. For example, the device may first determine Ts (or LF) from the measured v and then compare the measured Ts (or LF) to the nominal Ts (or LF) values.

[0160] In one example method, the device may first determine an access occasion randomly and then determine a LF within that access occasion (or another parameter such as the Ts, Tc, and so forth) using the method above. In another method, the device may first determine a LF (or another parameter) and then choose a random access (for example, randomly) within the set of access occasions associated with that LF (or another parameter).

[0161] In example another method, the device may measure K separate calibration signals wherein each calibration signal may correspond to a LF (or another parameter such as the Ts). The device may compare the K measured values to K nominal values and choose one (for example, the one with the smallest error or one from a set of value with corresponding error below a threshold)

[0162] In example another method, the device may measure a calibration symbol and compute Vk=m / (2k), k = 0, ...K-1 where DI may be the measurement. A nominal value of LF may be determined by using the methods outlines above (for example, by comparing the error values).

[0163] The one or more LFs applicable in an access occasion may be indicated in the QueryRep message. The device may first determine an access occasion and then determine the LF from the list of LFs signaled (for example, randomly or based on a measurement).

[0164] Energy level: The device may choose an LF based on the stored energy level. For example, if energy level is below a threshold, the device may choose a smaller LF that corresponds to longer symbols to improve coverage if backscattering is used.

[0165] Status of signal amplification: The device may choose a LF based on the status of signal amplification. For example, if the device is a type of device with an amplifier and the device has enough energy to amplify the transmitted signal, then the device may select a LF corresponding to a shorter symbol

[0166] An indication from the reader: Indicated by the reader, for example, as part of paging, Query, QueryRep, and / or implicitly by an association to the time / frequency resource.

[0167] Based on memory: The device may determine the LF using an information stored in its memory.

[0168] Based on device category and / or type, payload size, priority, for example, payload information priority, Based on last transmission, for example, last used link frequency.

[0169] The control message may contain an indication of what method(s) to use. For example, random selection using device ID may be enabled or disabled by the reader. In one solution, a bit “1” in Query, QueryRep or another message may indicate to the device to perform random selection based on the device ID and a bit “0” may indicate to the device to perform random selection not based on the device ID Similarly, the indication may indicate whether to use random selection or selection based on a measurement.

[0170] A device sends device ID or partial device ID in an example provided herein. Upon determining an access occasion and a link frequency, the device may initiate a first transmission. The initial transmission may be a transmission of a data packet that may include the device ID or a part of the device ID. In one example, the transmitted device ID may not include the bits that may be used to select the access occasion and / or the link frequency. In one method, the device may transmit to the reader information regarding the stored energy level and / or information regarding the payload size (for example, transport block size).

[0171] A device receives confirmation message in an example provided herein. After the initial message is transmitted, the device may monitor a channel / signal from the reader. The device may determine that a message, for example, a confirmation message and / or a scheduling message, is received.

[0172] The message may contain at least one of the following components: an acknowledgement or scheduling information.

[0173] Acknowledgment: The message may contain an acknowledgment (of the successful reception of the initial transmission) and / or an attribute of the message may be associated with an acknowledgment. The device may determine that the initial transmission is acknowledged if the message contains the device ID (full or part), for example, the random ID transmitted as part of the initial transmission.

[0174] Scheduling information: The message may contain information to schedule a subsequent transmission.

[0175] A few possible packet formats may be, for example, as the following: [preamble: message type (ACK): Device ID: postamble]; [preamble: message type (ACK + Scheduling): Device ID: scheduling information: postamble]; and [preamble: message type (ACK): Flag: Device ID: postamble] wherein the flag may indicate if the message contains scheduling information or not.

[0176] In another example method, a scheduling message may follow the acknowledgement (ACK) message as follows; and whether scheduling information is available or not may be indicted with a bitfield in the ACK message. For example: [preamble: message type (ACK): Device ID: postamble] [preamble: message type (SCH): Device ID: postamble].

[0177] The scheduling information may contain one or more of the following. Access occasion counter value: Upon receiving a counter value, the device may update the counter with the new value and decrementing the counter with each access occasion. The device may initiate the scheduled transmission when the counter-7J -hits zero. Additionally or alternatively, as explained above, the device may set the counter to an initial value (for example, 0), increment it with each access occasion, and initiate transmission when the counter hits the indicated value. In another method, the device may decrement (or increment) the counter only with each access occasion of a particular type (for example, access occasion for scheduled access).

[0178] In one example method, the device may keep separate counters for different access occasion types and the scheduling information may also indicate the counter type or the access occasion type.

[0179] In one example method, occasions (referred to as sub-occasions) may be available within an occasion. The device may be indicated to perform the subsequent transmission within one or more of these sub-occasions. The device may be indicated (e.g., by the reader) one or more of the following: the number of sub-occasions (e.g., within an occasion), the index of the one or a plurality of the sub-occasions to use for transmission. The index may be indicated by using one of the methods above, for example, by setting a counter to a specific value or by indicating an explicit index of a sub-occasion. The device may be indicated the start of sub-occasion with a message similar to QueryRep but other than QueryRep (for example, the message types are different) or an attribute of the QueryRep message by using one or more of the following: Bitfield within the QueryRep message. For example, a QueryRep message with "1” in a bitfield indicates access occasion and “0” indicates a sub-occasion within an occasion. Preamble: For example, a QueryRep message with first preamble indicates access occasion and a second preamble indicates sub-occasion.

[0180] In one example method, the QueryRep message may include a device ID or part of the ID; or an attribute of the QueryRep may be associated with the device ID (for example, the CRC of the message may be scrambled with the device ID or part of the device ID). In one example method, the QueryRep message may have an attribute to indicate to certain devices not to change the value of the counters these devices are keep. The attribute may be a bitfield in the message, or a preamble.

[0181] The scheduling information may further contain an access occasion index, and the device may initiate transmission in the indicated access occasion. Also, the scheduling information may contain a calibration signal (for example, as part of the preamble). The calibration signal may be used to determine the timing for the DL reception and / or UL transmission for the scheduled access, at least one measurement from which certain transmission parameters may be determined.

[0182] Additionally, the scheduling information may contain a link frequency or frequencies (orTc). Further, the scheduling information may contain values of coefficient(s) to act on the calibration signal measurements to determine certain transmission parameters.

[0183] Also, the scheduling information may contain the symbol duration (Ts). In addition, the scheduling information may contain the number of chips per symbol (M). Moreover, the scheduling information may contain one or more of a session ID; line coding scheme; modulation type; modulation order; frequency hopping enable / disable; and frequency hopping scheme (for example, within a symbol or across symbols).

[0184] A device transmits with the new parameters in an example provided herein. The device may initiate the subsequent transmission based on the scheduling information. After the transmission ends, the device may monitor an ACK or a negative ACK (NACK) message; or only a NACK message.

[0185] An example provided herein includes M-ary Manchester encoding. In one example method, the device and / or the reader may transmit an M-ary Manchester encoded data wherein the number of bits transmitted per symbol may be log2(M). The transmission may be from the reader to the device and / or from the device to the reader. For the purpose of illustration, the examples below may assume M= 4 and the reader as the transmitter.

[0186] In a line encoding scheme data bits may be mapped to physical symbols / signals. For example, when M = 2, then the conventional Manchester encoding scheme may be as follows wherein bit-0 is mapped to a symbol with “high” followed by “low” (falling edge) and bit-1 is mapped to a symbol with “low” followed by “high” (rising edge). In an alternative implementation, bit-0 and bit-1 may be mapped to rising edge and falling edge symbols, respectively. For the scheme introduced here, any of these implementations can be used.

[0187] FIG. 5 illustrates a Manchester encoding example. For M-ary encoding, in one method, data bits may be transmitted by using (i) symbols with different patterns of risin g / f al I i ng edges, and (i) symbols of varying duration. This approach may be applicable to other schemes than Manchester encoding.

[0188] In one example solution, m bits may be used to differentiate the rising / falling pattern; and log2(M) - m bits may be used to differentiate the duration of a symbol. In one solution for m = 1 , M symbols may be generated such that there may be (M / 2) pairs of symbols wherein the time duration of each pair is different than the others.

[0189] For example, with M = 4, some possible signals are shown below. In this example, symbols S1 and 82 are of length T1 and symbols S3 and S4 are of length T2 wherein T2>T1 , for example, T2 = 2 T1. For example, for 8-ary scheme, there may be 8 symbols wherein the first two symbols are of length T1 , the second two symbols are of length T2, the third two symbols are of length T3, and the last 2 symbols are of length T4. Log2(M) bits may be mapped to the symbols.

[0190] FIG. 6 illustrates Manchesterencoding with M = 4 symbols. FIG. 6 is an example that other mappings may be possible and still consistent with this method.

[0191] In one example method, M-ary Manchester encoding may be used by a device to transmit to a reader. The reader may transmit a calibration signal and the device may use the calibration signal to calibrate its transmission timing. In one solution, for m = 1 , the calibration signal may include log2(M) symbols wherein a first symbol may be of length C1 T1 , a second symbol may be of length C2T2, a third symbol may be of length C3T3, and so forth, wherein C1 , 02, C3, ... may be coefficients (for example, 01 = C2 = C3 ... = C) and maybe signaled and / or (pre)configured.

[0192] FIG. 7 shows an example of a calibration signal. In the example in FIG. 7, M=4. In general, the calibration signal may include lon2(M) - m + 1 symbols of different durations. The calibration signal may include symbols of all durations used in an encoding scheme (possibly after scaled by a coefficient).

[0193] Upon receiving the calibration signal, the device may measure the durations of individual symbols in the signal and compute the durations of the symbols to transmit using a function of the measured durations. For example, if the measured durations are t1 and t2 for the example above, the durations of symbols S1 and S2 may be determined as D1t1 and the durations of symbols S3 and S3 may be determined as D2t2 wherein D1 and D2 may be signaled and / or (pre)configured coefficients.

[0194] In one example method, M-ary Manchester encoding may be used by the reader to transmit to a device. The reader may transmit a calibration signal. The device may measure the duration of the first calibration symbol and the second calibration symbol. Assume these measurements are given by t1 and t2. Then the device may determine the T1 and T2 as F1t1 and F2t2 where F1 and F2 may be (pre)configured and / or signaled coefficients. When M = 4, then the device may transmit one of S1 to S4 depending on the bitpair wherein the durations of the symbols are F1t1 or F2t2

[0195] One example procedure to decode the received encoded symbols may be as follows:

[0196] The device computes a threshold value th, for example, th = (t1 + 12) / 2. Also, the device executes a decoding process wherein the device measures the duration of the received symbol as D. If D< th, then the symbol is either S1 or S2 (fist pair). If it is a falling edge, then the symbol is S1. If it is a rising edge, then the symbol is S2. If D>th, then the symbol is either S3 or S4 (second pair). If falling edge, then S3. If rising edge, then S4.

[0197] For M-ary signaling, the device may compute (M / 2)-1 threshold values such as th1 = (t1 + 12) / 2; th2 = (t2 + t3) / 2; th3 = (t3 + t4) / 2, and so forth. If D< th1 , then the symbol belongs to the first pair; if th1 <D<th2 then the symbol belongs to second pair; if th2<D<th3, then the symbol belongs to third pair; and so forth. The edge (rising or falling) may be used to determine the symbol within a pair.

[0198] Example solutions are provided herein. A main example solution summary is provided in the following.

[0199] A reader (for example, a UE) may perform one or more of the following actions. The reader transmits a preamble, wherein the preamble may contain a signal representing one or more symbol / bit (for example, bit 0, bit1) and at least one calibration signal Further, the reader transmits a control message (for example, in a Reader-to-Device channel) wherein the control message may contain one or more of the following.

[0200] The control message may contain a parameter to indicate the number of random access occasions. For example, the parameter may be Q, and the number of access occasions = 2^.

[0201] Also, the control message may contain signaling to indicate one or more of the Device-to-Reader link frequency or frequencies (chip duration), symbol duration (data rate) associated with each access occasion in a group of access occasions. For example, the signaling may indicate bitmap to F link frequencies for eachaccess occasion in a group of access occasions (for example, F may be the same for each access occasion). For example, example bitmap to Fi link frequencies for each access occasion i in a group of access occasions.

[0202] Further, the control message may contain signaling to enable / disable (for example, 1 enables, 0 disables; or vice versa) determination of random access occasion and / or the associated link frequency based on bits from the device ID (for example, random ID). For example, when enabled, the first Q MSBs of the device ID determines a time occasion and the next F (or Fi) MSBs determines a link frequency.

[0203] Also, the reader receives a transmission in an access occasion in each of one or more of the link frequencies indicated for the access occasion (for example, where each received transmission contains a random device ID). If at least one device ID is successfully detected, the reader performs one or more of the following for each of the successfully detected device IDs The reader transmits a confirmation message wherein the confirmation message may include one or more of the following: device ID (or part of the device ID); and one or more parameters for a subsequent transmission by the device, for example, a symbol duration, a link frequency, a chip rate (for example, for square wave frequency shifting), and / or a sub-occasion index

[0204] The reader may transmit to the device a Device-to-Reader calibration signal to be used for the subsequent transmission.

[0205] Moreover, the reader may transmit an indication in an access occasion that indicates when the suboccasion corresponding to the sub-occasion index starts. Further, the reader may receive data within the suboccasion from a device scheduled for the sub-occasion using the associated parameters (for example, BLF, chip rate, and so forth).

[0206] In a further example, a device (for example, a UE) receives a preamble wherein the preamble may contain a signal representing one or more symbol / bit (for example, bit O, bit1) and at least one calibration signal. Further, the device receives a control message (for example, in a Reader-to-Device channel) wherein the control message may contain one or more of the following. The control message may contain a parameter to indicate the number of random access occasions (for example, Q, number of access occasions = 2®).

[0207] Further, the control message may contain a signaling to indicate one or more of the Device-to- Reader link frequency or frequencies (chip duration), symbol duration (data rate) associated with each access occasion in a group of access occasions. For example, the control message may contain a bitmap to F link frequencies for each access occasion in a group of access occasions (for example, F may be the same for each access occasion). For example, the control message may contain a bitmap to Fi link frequencies for each access occasion i in a group of access occasions.

[0208] Also, the control message may contain a signaling to enable / disable (for example, 1 enables, 0 disables; or vice versa) determination of random access occasion and / or the associated link frequency based on bits from the device ID (for example, random ID). For example, when enabled, the first Q MSBs of the device ID determines a time occasion and the next F (or Fi) MSBs determines a link frequency.

[0209] If determination of random access occasion and / or the associated link frequency based on bits from the device ID is enabled, then the device determines an access occasion and a link frequency based on the randomly generated device ID Else the device determines randomly an access occasion and a link frequency.

[0210] Further, the device transmits an initial message.

[0211] Also, the device receives a confirmation message wherein the confirmation message may include one or more of the following: the device ID (or part of the device ID); or one or more parameters for a subsequent transmission by the device, for example, a symbol duration, a link frequency, a chip rate (for example, for square wave frequency shifting), and / or a sub-occasion index.

[0212] In addition, the device receives a calibration signal associated with the link frequency indicated in the confirmation message. Further, the device receives an indication in an access occasion that indicates when the sub-occasion corresponding to the sub-occasion index starts.

[0213] Moreover, the device transmits data within the sub-occasion using the associated parameters (for example, BLF, chip rate, and so forth).

[0214] FIG. 8 illustrates an example call flow for the establishment of the communication between the reader device and the target device (for example, tag).

[0215] FIG. 9 shows an example flow chart for a reader device for the establishment of communication with another device.

[0216] The examples in FIG. 8 and FIG. 9 are for illustration purposes and should not limit the scope of the solution described.

[0217] A reader device 880, 980 may transmit a preamble 810, 910 to a target device (Tag) 840. The preamble may include a signal representing one or more symbols / bits (for example, bit 0, bit 1) and at least one calibration signal. In an example, the reader device may be an interrogator. Additionally or alternatively, the reader device may be a WTRU. For example, the reader device may be a first WTRU. Further, the target device may be a WTRU, such as a second WTRU, in an example. Additionally or alternatively, the calibration signal is for a subsequent transmission. The target device may perform a random access procedure.

[0218] The reader device 880, 980 may transmit a control message 820, 920 to the target device 840. The control message may include information associated with each random access occasion from a group of random access occasions. Additionally or alternatively, the information associated with each random access occasion from a group of random access occasions includes at least one of: an indication of the number of random access occasions in the group, an indication of one or more link frequencies or chip durations associated with each random access occasion; a symbol duration associated with each random access occasion; a parameter enabling or disabling the usage of bits from a device identity (ID) to determine a random access occasion and / or the link frequency associated with the random access occasion. The device ID may be randomly generated. Additionally or alternatively, the device ID may be generated by a random number generator.

[0219] Based on the received information, the target device 840 may determine an access occasion from the group of random access occasions 825. The target device 840 may use the determined access occasion for a first data transmission. If the determination of the access occasion and / or the associated link frequency based on bits from the device ID is enabled, the random access occasion and the link frequency may be determined based on the randomly generated device ID. The number of bits and pattern of the bits (MSB, LSB, and so forth) to be used by the target device may be pre-configured in the target device. Optionally, this information may be included in the control message sent from the reader device to the target device, which was described above. If the determination of a random access occasion and / or the associated link frequency based on bits from the device ID is disabled, then the determination of the access occasion may be random.

[0220] Accordingly, the target device 840 may transmit a first message in the determined random access occasion 830. Upon receiving the first message 930, the reader device 880, 980 may transmit a confirmation message 950. Additionally or alternatively, the confirmation message includes an ID of the target device. Additionally or alternatively, the confirmation message includes a link frequency. Additionally or alternatively, the confirmation message includes a sub-occasion index. The confirmation message may include configuration parameters to be used by the target device 840 in a subsequent transmission, including a sub-occasion index 850. The reader device 880, 980 may transmit a device-to-reader calibration signal 860, 960 to the target device 840. Additionally or alternatively, reader device 880, 980 may transmit a reader-to-device calibration signal 860 to the target device 840. The reader device 880, 980 may transmit timing information associated with the suboccasion index 870 to the target device 840. The timing information may indicate when the sub-occasion associated to the sub-occasion index starts, in an example.

[0221] The target device 840 may use the information received from the reader device 880, 980 to send a subsequent transmission. Accordingly, the target device 840 may prepare to send a subsequent transmission within a sub-occasion associated with the sub-occasion index 875. The target device 840 may send the subsequent transmission within a sub-occasion associated with the sub-occasion index 890, using the timing information associated with the sub-occasion index received from the reader device in the confirmation message. The reader device 880, 980 may receive the subsequent transmission within the sub-occasion associated with the sub-occasion index 970. Additionally or alternatively, the reader device 880, 980 may receive the subsequent transmission using the link frequency.

[0222] 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, magneto-optical 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

CLAIMSWhat is claimed:

1. A method to be performed by a first wireless transmit / receive unit (WTRU), the method comprising: transmitting, to a second WTRU, a first preamble including a first calibration signal; transmitting, to the second WTRU, a control message, wherein the control message includes information associated one or more random access occasions from a group of random access occasions; receiving, from the second WTRU, a first message in a first sub-occasion of a random access occasion of the one or more random access occasions; transmitting, to the second WTRU, a confirmation message including an identity (ID) of the second WTRU, and one or both of a link frequency or a sub-occasion index; transmitting, to the second WTRU, a second preamble including a second calibration signal; and receiving, from the second WTRU, a second message using one or both of a second suboccasion indicated by the sub-occasion index or the link frequency.

2. The method of claim 1 wherein the preamble includes a signal representing one or more bits3. The method of claim 1 , wherein the preamble includes a signal representing one or more symbols.

4. The method of claim 1 , wherein the control message further comprises at least one of: an indication of the number of random access occasions in the group, an indication of one or more link frequencies or chip durations associated with each random access occasion; a symbol duration associated with each random access occasion; a parameter enabling or disabling the usage of bits from a device identity (ID) to determine a random access occasion and / or the link frequency associated with the random access occasion.

5. The method of claim 4, wherein the device ID is generated randomly.

6. The method of claim 1, wherein the confirmation message includes configuration parameters to be used by the second WTRU in a subsequent transmission.

7. The method of claim 1 , wherein the configuration parameters to be used by the second WTRU in a subsequent transmission include a sub-occasion index.

8. The method of claim 7, further comprising, transmitting, to the second WTRU, timing information associated with the sub-occasion index, wherein the timing information indicates when the suboccasion associated to the sub-occasion index starts9. The method of claim 1 , wherein the first calibration signal is for a subsequent transmission.

10. The method of claim 1, wherein the second calibration signal is a device-to-reader calibration signal.

11. A first wireless transmit / receive unit (WTRU) comprising: a processor; and a transceiver operatively coupled to the processor; wherein: the processor and the transceiver are configured to transmit, to a second WTRU, a first preamble including a first calibration signal; the processor and the transceiver are configured to transmit, to the second WTRU, a control message, wherein the control message includes information associated one or more random access occasions from a group of random access occasions; the transceiver is configured to receive, from the second WTRU, a first message in a first sub-occasion of a random access occasion of the one or more random access occasions; the processor and the transceiver are configured to transmit, to the second WTRU, a confirmation message including an identity (ID) of the second WTRU, and one or both of a link frequency or a sub-occasion index; the processor and the transceiver are configured to transmit, to the second WTRU, a second preamble including a second calibration signal; and the transceiver is configured to receive, from the second WTRU, a second message using one or both of a second sub-occasion indicated by the sub-occasion index or the link frequency.

12. The WTRU of claim 11 , wherein the preamble includes a signal representing one or more bits.

13. The WTRU of claim 11 , wherein the preamble includes a signal representing one or more symbols.

14. The WTRU of claim 11 , wherein the control message further comprises at least one of: an indication of the number of random access occasions in the group, an indication of one or more link frequencies or chip durations associated with each random access occasion; a symbol duration associated with each random access occasion; a parameter enabling or disabling the usage of bits from a device identity (ID) to determine a random access occasion and / or the link frequency associated with the random access occasion.

15. The WTRU of claim 14, wherein the device ID is generated randomly.

16. The WTRU of claim 11 , wherein the confirmation message includes configuration parameters to be used by the second WTRU in a subsequent transmission.

17. The WTRU of claim 11, wherein the configuration parameters to be used by the second WTRU in a subsequent transmission include a sub-occasion index.

18. The WTRU of claim 17, further comprising, transmitting, to the second WTRU, timing information associated with the sub-occasion index, wherein the timing information indicates when the suboccasion associated to the sub-occasion index starts19. The WTRU of claim 11, wherein the first calibration signal is for a subsequent transmission.

20. The WTRU of claim 11, wherein the second calibration signal is a device-to-reader calibration signal.

Images