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Title:
METHODS AND PROCEDURES FOR HARQ MANAGEMENT IN NR-BASED NON-TERRESTRIAL NETWORKS
Document Type and Number:
WIPO Patent Application WO/2019/160737
Kind Code:
A1
Abstract:
A method and apparatus for operation by a WTRU are provided. A WTRU may determine whether to disable HARQ operation for TBs or CBGs which exceed a max-HARQ-size. The max-HARQ-size may be calculated by the WTRU. In one embodiment, the max-HARQ-size may be based on a memory size of the WTRU or may be based on a propagation delay between the WTRU and the gNB. The propagation delay may be determined from a random access response (RAR) received from the gNB.

Inventors:
HOSSEINIAN SEYED (US)
NAYEB NAZAR SHAHROKH (US)
TAHERZADEH BOROUJENI MAHMOUD (US)
Application Number:
PCT/US2019/016984
Publication Date:
August 22, 2019
Filing Date:
February 07, 2019
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
IDAC HOLDINGS INC (US)
International Classes:
H04L1/18
Foreign References:
US20140153529A12014-06-05
US20140036808A12014-02-06
US20170317791A12017-11-02
Other References:
FRAUNHOFER IIS ET AL: "NTN NR impacts on the HARQ Operation", vol. TSG RAN, no. Lisbon, Portugal; 20171218 - 20171221, 17 December 2017 (2017-12-17), XP051365081, Retrieved from the Internet [retrieved on 20171217]
Attorney, Agent or Firm:
NACCARELLA, Theodore (US)
Download PDF:
Claims:
CLAIMS

What is claimed is:

1. A method for Hybrid Automatic Repeat Request, HARQ, operation by a network node, the method comprising:

obtaining, by the network node, information related to a wireless transmit / receive unit, WTRU;

determining, by the network node, whether hybrid automatic repeat request, HARQ, should be enabled or disabled for at least a packet to be transmitted; and

transmitting, by the network node, to the WTRU information regarding whether HARQ is enabled or disabled for at least the packet.

2. The method of claim 1 , wherein the information related to the WTRU is at least one of memory size and propagation delay.

3. The method of claim 2, wherein the information related to the WTRU is memory size and is provided by the WTRU to a network comprising the network node.

4. The method of claim 3, wherein the network obtains the information related to the WTRU during a registration process for the WTRU.

5. The method of claim 4, wherein the network node obtains the information related to the WTRU from the WTRU.

6. The method of claim 2, wherein the information related to the WTRU comprises propagation delay between the network node and the WTRU and the method further comprises:

estimating, by the network node, the propagation delay.

7. The method of claim 1 , wherein the information related to the WTRU depends on a network type of a network to which the WTRU and the network node belong and wherein it is determined to disable HARQ in case the network type is Non-Terrestrial Network, NTN.

8. The method of claim 1 , further comprising:

receiving, by the network node from the WRTU, acknowledgement information related to a packet; and responsive to the acknowledgement information indicating unsuccessful decoding of the packet and that HARQ is enabled for the packet, retransmitting, by the network node, the packet.

9. The method of claim 1 , wherein the information regarding whether HARQ is enabled or disabled is provided by a number indicating a number of HARQ processes, wherein a Ό’ indicates that HARQ is disabled.

10. The method of claim 1 , wherein the WTRU has a maximum number of supportable HARQ processes and wherein the information regarding whether HARQ is enabled or disabled comprises a number that indicates that HARQ is enabled in case the number is lower than or equal to the maximum number of supportable HARQ processes and disabled in case the number is higher than the maximum number of supportable HARQ processes.

1 1. The method of claim 1 , wherein the information regarding whether HARQ is enabled or disabled comprises a bit for which‘T indicates enabled and Ό’ disabled or vice versa.

12. A method for operation by a wireless transmit / receive unit, WTRU, the method comprising:

determining, by the WTRU, a maximum size for a received packet that may be used in a hybrid automatic repeat request, HARQ;

transmitting, by the WTRU, the maximum size to a network node to which the WTRU is connected; determining, by the WTRU, whether a size of a packet received from the network node is greater than the maximum size; and

in case the size of the received packet is greater than the maximum size, treating, by the WTRU, the received packet as a transmission for which HARQ is disabled.

13. The method of claim 12, wherein treating the received packet as a transmission for which HARQ is disabled comprises not storing the packet in HARQ memory.

14. The method of claim 12, further comprising, if the size of the received packet is not greater than the maximum size, treating, by the WTRU, the received packet as a transmission for which HARQ is enabled.

15. The method of claim 14, wherein treating the received packet as a transmission for which HARQ is enabled comprises storing the packet in HARQ memory and sending acknowledgment information to the network node.

16. The method of claim 12, wherein the maximum size is determined based on at least HARQ memory size and a propagation delay to the network node.

17. A method for Hybrid Automatic Repeat Request, HARQ, operation by a network node, the method comprising:

receiving, by the network node, from a wireless transmit / receive unit, WTRU, a maximum size for a received packet to be used in a hybrid automatic repeat request, HARQ;

sending, by the network node, a packet to the WTRU; and

responsive to the size of the packet being greater than the maximum size, disabling, by the network node, HARQ for the packet; otherwise enabling, by the network node, HARQ for the packet.

18. A method for operation by a wireless transmit / receive unit, WTRU, the method comprising:

decoding, by the WTRU, a packet received from a next generation Node B, network node;

upon determination that the packet is not correctly decoded, determine, by the WTRU, whether a current number of hybrid automatic repeat request, HARQ, processes for which items of information relating to unsuccessful decoding of packets have been sent to the network node is lower than a maximum number of HARQ processes; and

in case the current number of items is lower than the maximum number of HARQ processes, enabling, by the WTRU, HARQ process for the received packet.

19. The method of claim 18, wherein enabling HARQ process for the received packet comprises storing decoded information from the received packet in HARQ memory and indicating to the network node that HARQ is enabled for the packet.

20. The method of claim 18, further comprising, if the current number of items is not lower than the maximum number of HARQ processes, disabling, by the WTRU, HARQ process for the received packet.

21. The method of claim 20, wherein disabling HARQ process for the received packet comprises at least not storing decoded information from the received packet in HARQ memory and indicating to the network node that HARQ is disabled for the packet.

22. The method of claim 18, further comprising calculating, by the WTRU, the maximum number of HARQ processes based on at least one of HARQ memory size, capability of the WTRU and a category of the WTRU.

23. A method for operation by a wireless transmit / receive unit, WTRU, the method comprising:

determining, by the WTRU, a maximum round-trip time to a network node to which the WTRU is connected; calculating, by the WTRU, based on the maximum round-trip time and size of a hybrid automatic repeat request, HARQ, memory of the WTRU, at least one of a maximum transport block size and a rate for limited buffer rate matching; and

sending, by the WTRU, to the network node the at least one of the maximum transport block size and the rate for limited buffer rate matching.

Description:
METHODS AND PROCEDURES FOR HARQ MANAGEMENT IN NR-BASED NON-TERRESTRIAL

NETWORKS

SUMMARY

[1] A method and apparatus for operation by a wireless transmit / receive unit (WTRU) are provided. The method may comprise determining a maximum number of hybrid automatic repeat request (HARQ) processes supportable by the WTRU. The WTRU may then transmit to a next generation Node B (gNB), the determined maximum number of HARQ processes. The gNB may be configured to halt initiation of a new HARQ process session for the WTRU if the gNB reaches the maximum number of HARQ processes. In this way, until the WTRU sends an acknowledgement (ACK) to the gNB, the gNB may not cause a new HARQ process session to be initiated. The maximum number of HARQ processes may be determined using a worst-case scenario method or may be determined via a block error rate (BLER) target method. The maximum number of HARQ processes may be indicated to the gNB via uplink control information (UCI) signaling.

[2] A WTRU may determine whether to disable HARQ operation for transport blocks (TBs) or code block groups (CBGs) which exceed a maximum size (max-HARQ-size). The max-HARQ-size may be calculated by the WTRU. In one embodiment, the max-HARQ-size may be based on a memory size of the WTRU or may be based on a propagation delay between the WTRU and the gNB. The propagation delay may be determined from a random access response (RAR) received from the gNB.

BRIEF DESCRIPTION OF THE DRAWINGS

[3] 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:

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

[5] 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;

[6] FIG. 1 C 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. 1 A according to an embodiment;

[7] FIG. 1 D 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;

[8] FIG. 2 is an illustration of an example of non-terrestrial access architecture with a latency requirement; [9] FIG. 3 is a hybrid automatic repeat request (HARQ) process timing diagram with a configured number of HARQ processes;

[10] FIG. 4 is a flowchart that illustrates a procedure for non-terrestrial HARQ management using a configured number of HARQ processes at a WTRU;

[1 1] FIG. 5 is a flowchart that illustrates a next generation Node B (gNB) procedure for non-terrestrial HARQ management using adaptive block error rate (BLER) target (BLER-Target);

[12] FIG. 6 is a flowchart that illustrates a procedure for non-terrestrial HARQ management using adaptive BLER-Target;

[13] FIG. 7 is a flowchart that illustrates a WTRU procedure for non-terrestrial HARQ management using WTRU Specific selective Disable/Enable HARQ;

[14] FIG. 8 is flowchart that illustrates an exemplary WTRU procedure for autonomous HARQ disable/enable performed by the WTRU;

[15] FIG. 9 is a flowchart that illustrates a procedure for determining and indicating the maximum transport block size (TBS);

[16] FIG. 10 is a flowchart that illustrates a procedure for determining and indicating the rate for the limited buffer rate matching (LBRM); and

[17] FIG. 1 1 is a flowchart that illustrates a procedure for jointly determining and indicating the maximum TBS and the rate for the LBRM.

DETAILED DESCRIPTION

EXEMPLARY NETWORKS FOR IMPLEMENTATION OF THE EMBODIMENTS

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

[19] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a radio access network (RAN) 104, a core network (CN) 106, a public switched telephone network (PSTN) 108, the Internet 1 10, and other networks 1 12, though it will be appreciated that the disclosed embodiments contemplate any number of WTRUs, base stations, networks, and/or network elements. Each of the WTRUs 102a, 102b, 102c, 102d may be any type of device configured to operate and/or communicate in a wireless environment. By way of example, the WTRUs 102a, 102b, 102c, 102d, any of which may be referred to as a“station” and/or a“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 (e.g., remote surgery), an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts), a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. Any of the WTRUs 102a, 102b, 102c and 102d may be interchangeably referred to as a UE.

[20] The communications system 100 may also include a base station 114a and/or a base station 1 14b. Each of the base stations 1 14a, 1 14b 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 I nternet 1 10, and/or the other networks 112. By way of example, the base stations 1 14a, 1 14b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a gNB, a NR NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 1 14a, 1 14b are each depicted as a single element, it will be appreciated that the base stations 114a, 1 14b may include any number of interconnected base stations and/or network elements.

[21] The base station 1 14a 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, etc. The base station 114a and/or the base station 1 14b 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 1 14a may be divided into three sectors. Thus, in one embodiment, the base station 1 14a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 1 14a 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. [22] The base stations 114a, 1 14b may communicate with one or more of the WTRUs 102a, 102b, 102c, 102d over an air interface 1 16, which may be any suitable wireless communication link (e.g., radio frequency (RF), microwave, centimeter wave, micrometer wave, infrared (IR), ultraviolet (UV), visible light, etc.). The air interface 116 may be established using any suitable radio access technology (RAT).

[23] 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 1 14a 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 1 16 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (FISPA+). HSPA may include High-Speed Downlink (DL) Packet Access (FISDPA) and/or High-Speed Uplink (UL) Packet Access (HSUPA).

[24] In an embodiment, the base station 1 14a 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 1 16 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE- A Pro).

[25] In an embodiment, the base station 1 14a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access, which may establish the air interface 116 using New Radio (NR).

[26] In an embodiment, the base station 1 14a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 1 14a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity (DC) principles. Thus, the air interface utilized by WTRUs 102a, 102b, 102c may be characterized by multiple types of radio access technologies and/or transmissions sent to/from multiple types of base stations (e.g., a eNB and a gNB).

[27] In other embodiments, the base station 1 14a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.1 1 (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.

[28] The base station 114b in FIG. 1 A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 1 14b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.1 1 to establish a wireless local area network (WLAN). In an embodiment, the base station 1 14b and the WTRUs 102c, 102d may implement a radio technology such as I EEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 1 14b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 1 14b may have a direct connection to the Internet 1 10. Thus, the base station 1 14b may not be required to access the Internet 1 10 via the CN 106.

[29] The RAN 104 may be in communication with the CN 106, which may be any type of network configured to provide voice, data, applications, and/or voice over internet protocol (VoIP) services to one or more of the WTRUs 102a, 102b, 102c, 102d. The data may have varying quality of service (QoS) requirements, such as differing throughput requirements, latency requirements, error tolerance requirements, reliability requirements, data throughput requirements, mobility requirements, and the like. The CN 106 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1 A, 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.

[30] The CN 106 may also serve as a gateway for the WTRUs 102a, 102b, 102c, 102d to access the PSTN 108, the Internet 1 10, and/or the other networks 1 12. 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 other networks 112 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the other networks 1 12 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104 or a different RAT.

[31] Some or all of the WTRUs 102a, 102b, 102c, 102d in the communications system 100 may include multi-mode capabilities (e.g., the WTRUs 102a, 102b, 102c, 102d may include multiple transceivers for communicating with different wireless networks over different wireless links). For example, the WTRU 102c shown in FIG. 1A may be configured to communicate with the base station 114a, which may employ a cellular- based radio technology, and with the base station 1 14b, which may employ an IEEE 802 radio technology.

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

102 may include a processor 1 18, 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 positioning system such as 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.

[33] The processor 1 18 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) circuits, 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 1 18 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 1 18 and the transceiver 120 as separate components, it will be appreciated that the processor 1 18 and the transceiver 120 may be integrated together in an electronic package or chip.

[34] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 1 14a in FIG. 1A) 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.

[35] Although the transmit/receive element 122 is depicted in FIG. 1 B as a single element, the WTRU 102 may include any number of transmit/receive elements 122. More specifically, the WTRU 102 may employ MIMO technology. Thus, in one embodiment, the WTRU 102 may include two or more transmit/receive elements 122 (e.g., multiple antennas) for transmitting and receiving wireless signals over the air interface 116.

[36] 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 802.1 1 , for example.

[37] The processor 1 18 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 1 18 may also output user data to the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128. In addition, the processor 1 18 may access information from, and store data in, any type of suitable memory, such as the non-removable memory 130 and/or the removable memory 132. The non-removable memory 130 may include random-access memory (RAM), read-only memory (ROM), a hard disk, or any other type of memory storage device. The removable memory 132 may include a subscriber identity module (SIM) card, a memory stick, a secure digital (SD) memory card, and the like. In other embodiments, the processor 1 18 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).

[38] The processor 1 18 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li- ion), etc.), solar cells, fuel cells, and the like.

[39] The processor 1 18 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over the air interface 116 from a base station (e.g., base stations 1 14a, 1 14b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[40] The processor 1 18 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, and/or a humidity sensor. [41] The WTRU 102 may include a full duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for both the UL (e.g., for transmission) and downlink (e.g., for reception) may be concurrent and/or simultaneous. The full duplex radio may include an interference management unit (not shown) to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 1 18). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[42] FIG. 1 C 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 1 16. The RAN 104 may also be in communication with the CN 106.

[43] 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 1 16. In one embodiment, the eNode-Bs 160a, 160b, 160c may implement MIMO technology. Thus, the eNode-B 160a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a.

[44] 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.

[45] The CN 106 shown in FIG. 1 C may include a mobility management entity (MME) 162, a serving gateway (SGW) 164, and a packet data network (PDN) gateway (or PGW) 166. While each of 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.

[46] 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. [47] 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.

[48] 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 1 10, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices.

[49] The CN 106 may facilitate communications with other networks. For example, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to circuit-switched networks, such as the PSTN 108, to facilitate communications between the WTRUs 102a, 102b, 102c and traditional land-line communications devices. For example, the CN 106 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 106 and the PSTN 108. In addition, the CN 106 may provide the WTRUs 102a, 102b, 102c with access to the other networks 1 12, which may include other wired and/or wireless networks that are owned and/or operated by other service providers.

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

[51] In representative embodiments, the other network 1 12 may be a WLAN.

[52] 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 an access or an interface to a Distribution System (DS) or another type of wired/wireless network that carries traffic into and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. The peer-to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.1 1e DLS or an 802.11 z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the STAs (e.g., all of the STAs) within or using the IBSS may communicate directly with each other. The IBSS mode of communication may sometimes be referred to herein as an“ad-hoc” mode of communication. [53] When using the 802.1 1 ac infrastructure mode of operation or a similar mode of operations, the AP may transmit a beacon on a fixed channel, such as a primary channel. The primary channel may be a fixed width (e.g., 20 MHz wide bandwidth) or a dynamically set width via signaling. 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 in 802.11 systems. For CSMA/CA, the STAs (e.g., every STA), including the AP, may sense the primary channel. If the primary channel is sensed/detected and/or determined to be busy by a particular STA, the particular STA may back off. One STA (e.g., only one station) may transmit at any given time in a given BSS.

[54] 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.

[55] Very High Throughput (V HT) STAs may support 20 MHz, 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 non-contiguous 80 MHz channels, which may be referred to as an 80-^0 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).

[56] Sub 1 GHz modes of operation are supported by 802.1 1 af and 802.1 1 ah. The channel operating bandwidths, and carriers, are reduced in 802.1 1 af and 802.1 1 ah relative to those used in 802.1 1 n, and 802.1 1 ac. 802.1 1 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, 802.1 1 ah may support Meter Type Control/Machine-Type Communications (MTC), such as MTC devices in a macro coverage area. MTC devices may have certain capabilities, for example, limited capabilities including support for (e.g., only support for) certain and/or limited bandwidths. The MTC devices may include a battery with a battery life above a threshold (e.g., to maintain a very long battery life).

[57] WLAN systems, which may support multiple channels, and channel bandwidths, such as

802.1 1 n, 802.11 ac, 802.1 1 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 802.1 1 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[58] 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.

[59] FIG. 1 D is a system diagram illustrating the RAN 1 13 and the CN 1 15 according to an embodiment. As noted above, the RAN 113 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over the air interface 1 16. The RAN 1 13 may also be in communication with the CN 1 15.

[60] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 1 13 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 1 16. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 180b, 180c may utilize beamforming to transmit signals to and/or receive signals from the WTRUs 102a, 102b, 102c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a. 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).

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

[62] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs 102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c in FIG. 1C). 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 (in FIG. 1C). 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.

[63] 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, dual connectivity, 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. 1 D, the gNBs 180a, 180b, 180c may communicate with one another over an Xn interface.

[64] The CN 115 shown in FIG. 1D 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 each of the foregoing elements are depicted as part of the CN 115, it will be appreciated that any of these elements may be owned and/or operated by an entity other than the CN operator.

[65] The AMF 182a, 182b may be connected to one or more of the gNBs 180a, 180b, 180c in the

RAN 113 via an N2 interface and may serve as a control node. For example, the AMF 182a, 182b may be responsible for authenticating users of the WTRUs 102a, 102b, 102c, support for network slicing (e.g., handling of different Protocol Data Unit (PDU) sessions with different requirements), selecting a particular SMF 183a,

183b, management of the registration area, termination of 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 machine type communication (MTC) access, and/or the like. The AMF 162 may provide a control plane function for switching between the RAN 1 13 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.

[66] The SMF 183a, 183b may be connected to an AMF 182a, 182b in the CN 1 15 via an N11 interface. The SMF 183a, 183b may also be connected to a UPF 184a, 184b in the CN 1 15 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 downlink data notifications, and the like. A PDU session type may be IP-based, non-IP based, Ethernet-based, and the like.

[67] The UPF 184a, 184b may be connected to one or more of the gNBs 180a, 180b, 180c in the RAN 1 13 via an N3 interface, which may provide the WTRUs 102a, 102b, 102c with access to packet-switched networks, such as the Internet 1 10, 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 downlink packets, providing mobility anchoring, and the like.

[68] The CN 1 15 may facilitate communications with other networks. For example, the CN 115 may include, or may communicate with, an IP gateway (e.g., an IP multimedia subsystem (IMS) server) that serves as an interface between the CN 1 15 and the PSTN 108. In addition, the CN 1 15 may provide the WTRUs 102a, 102b, 102c with access to the other networks 1 12, 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 Data Network (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.

[69] In view of Figures 1 A-1 D, and the corresponding description of Figures 1 A-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.

[70] 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 may performing testing using over-the-air wireless communications.

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

HARQ MANAGEMENT IN NON-TERRESTRIAL NETWORKS

[72] The roles and advantages of satellites in 5G have been studied by 3GPP. That effort lead to the specific requirement to support satellite access that are captured in TS 22.261 [1]. Therein, it is recognized that, as part of the mix of access technologies for 5G, satellite coverage brings added value, especially for mission critical and industrial applications where ubiquitous coverage and availability is crucial.

[73] Satellites refer to spaceborne vehicles, including, but not limited to vehicles in Low Earth Orbits (LEO), Medium Earth Orbits (MEO), Geostationary Earth Orbit (GEO) or in Highly Elliptical Orbits (HEO).

[74] Beyond satellites, non-terrestrial networks (NTN) refer to networks or sections of networks that use other airborne or spaceborne vehicles for transmission. Airborne vehicles include, but are not limited to, High Altitude Platform Stations (HAPS) encompassing Unmanned Aircraft Systems (UAS) - including tethered UAS, Lighter than Air UAS and Heavier than Air UAS - all operating at altitude; typically between 8 and 50 km, including quasi-stationary UAS.

[75] The 5G system should be equipped to provide services using satellite access. It also should support service continuity between land-based 5G access and satellite-based access networks owned by the same operator or by an agreement between different operators. To provide services using satellite access, the air interface of the 5G system should support a one-way latency of no more than 300 ms. FIG. 2 is an illustration of an example of non-terrestrial access architecture 200 with a latency requirement. The architecture 200 includes a terminal 210 such as a WTRU and a network device 230 such as a gateway or a gNB in communication via a platform 220 that is spaceborne or airborne and relays the traffic between the terminal 210 and the network device 230. It will be appreciated that owing to the distance between the terminal 210 and the platform 220 on the one hand and the platform 220 and the network device 230 on the other, there is a substantial latency that, as mentioned, could be up to 300 ms for each leg while still being supported by the 5G system.

[76] A HARQ scheme has been adopted in most mobile communication systems since the 3rd generation (3G). There are three types of HARQ schemes, namely; type I, type II, and type III. Type I adds error detection (ED) and forward error correction (FEC) information to the message and the receiver first corrects errors using the FEC, then detects errors using the ED and, if necessary, possibly requests retransmission of the message. Type II sends only ED along with an initial message and the receiver requests FEC information only if at least one error is detected; and retransmissions are possible if the FEC does not correct the error(s). Type III can be said to be a particular case in which every (re)transmission should be independently self- decodable. Among them, type II and type III require a receive buffer. Compared with HARQ type III, the performance of HARQ type II is more affected by the size of the receive buffer, because any shortage of the receive buffer may incur consecutive packet errors. The receive buffer has space for a number of HARQ processes, where a different HARQ process is needed for each received message until determined to be correct or is removed for other reasons (such as if error correction is to be handled by a higher level). For continuous transmissions, the number of possible HARQ processes is determined by the following equation:

Equation 1

[77] In Equation 1 , NHARQ represents the number of HARQ processes, and T P , T Sf , T ue , Tack, and Tnb are: propagation delay, subframe duration, WTRU processing time, ACK/NACK transmission time, and gNB processing time, respectively. Tt is the total time that it takes between sending a packet by gNB and receiving ACK/NACK feedback. In the case of the terrestrial network systems, the propagation delay between a base station and a mobile terminal, T P , is negligible compared to the other processing time values, and this typically results in a NHARQ of 8 or 16 (e.g. 8 for LTE and 8 or 16 being typical values for NR systems). Consequently, 3GPP LTE and NR user terminals are equipped with correspondingly sized buffers.

[78] In the case of the non-terrestrial systems, however, T P is not negligible. For instance, for an extreme case such as GEO bent-pipe satellite system, T P is about 300 ms, which results in NHARQ values of about 600.

[79] Given the number of HARQ processes NHARQ, the required size of a receiver memory, Mk, is determined by Equation 2.

NI r x — N HAR Q · N tr · M p , Equation 2 [80] In Equation 2, Ntr is the maximum number of transmissions for a packet including retransmissions, and M P is the size of the packet. Since the values of Ntr and M P for both non-terrestrial and terrestrial systems are the same, Mrx of the non-terrestrial communication system can be almost 75 (= 600 ÷ 8) times larger (in a typical worst-case scenario) than that of the terrestrial system. This may mean that a terrestrial user terminal cannot be used for non-terrestrial systems. This problem becomes even more serious for HARQ type II. Since, in HARQ type II, the initial transmission packet contains only the systematic bits of a code block, i.e. the message and the ED bits, then the failure of storing these systematic bits due to the shortage of the memory may make all succeeding retransmission efforts of FEC parity bits useless.

[81] Embodiments are provided to address the issue of the substantial requirements for expensive PHY layer memory in non-terrestrial receiver structure. In NR, for DL, limited buffer rate matching (LBRM) is supported and is applied per HARQ process. NR limits transmit buffer corresponding to a largest Transport Block Size (TBS) coded at rate LBRM (RLBRM), where RLBRM is 1/2. As already mentioned, in non-terrestrial networks, the number of HARQ processes may be much larger than 16 as defined in terrestrial NR, which can mean that the WTRU HARQ buffer size adapted for terrestrial networks, i.e. for example 16, is not sufficient to support the larger number of HARQ processes that may be required in non-terrestrial networks. Therefore, methods which can efficiently manage the available soft buffer at the WTRU for a larger number of HARQ processes, say more than 16, are needed.

[82] In the embodiments, a WTRU calculates, for example based on its HARQ buffer size, the number of maximum HARQ processes (max-number-HARQ-process) that it may support or will support. Then a WTRU may transmit max-number-HARQ-process to gNB. This may be done via Uplink Control Information, UCI, or any other uplink control configuration signaling. The transmission of max-number-HARQ-process may be done autonomously by a WTRU or may be done in response to a preceding request from a gNB. A WTRU may choose to calculate max-number-HARQ-process using any suitable method. Three methods are given here as nonlimiting examples: a worst-case scenario method, a block error rate (BLER) target method and an adaptive BLER-target method.

[83] Worst-case scenario method: In this method, a WTRU calculates max-number-HARQ-process for a worst-case scenario. That is to say, the WTRU assumes all receiving packets can be erroneous and prepares for this eventuality. Based on available memory size, i.e. HARQ buffer size, and packet size, a value for max-number-HARQ-process is calculated in such a way as to ensure that all arriving packets in different HARQ processes have enough space to be stored in the WTRU’s HARQ memory, in case every single packet (re)transmission is a failure, i.e.: max-number-HARQ-process = Mrx Equation 3

[84] BLER target method: In this method, a WTRU calculates max-number-HARQ-process for a more optimistic scenario compared to the worst-case scenario. That is to say, the WTRU assumes received packets may be erroneous with a probability of BLER-Target. A typical value for BLER-Target is 10%. It means that the WTRU assumes that, on average, a fraction of arriving packets with a rate of BLER-Target may not be decodable. So, the WTRU on average only needs to store a fraction of arriving packets for HARQ processes. Based on the available memory size Mrx, packet size M P , and BLER-Target PBLER, a value for max-number- HARQ-process is calculated in such a way as to ensure that arriving packets for different HARQ processes have enough space to be stored in WTRU’s HARQ memory, in case only BLER-Target of packets (re)transmissions fail, i.e.: max-number-HARQ-process = TX - , Equation 4

N tr Mp PBLER . ^

[85] The parameter BLER-Target is an optional configurable parameter, by which the gNB can configure a WTRU.

[86] Before describing the third method, the adaptive BLER-target method, it is noted that it may happen that no matter what method is used for the calculation of max-number-HARQ-process, the resulting value is lower than a suggested number of HARQ processes based on transmission times, etc. In other words, there may not be enough space in the WTRU’s HARQ memory for the necessary (or deemed to be necessary) HARQ processes. This may mean that a gNB has to halt initiating a new HARQ process session once the max-number- HARQ-process has been reached, and then to wait for reception of an ACK from the WTRU (liberating a HARQ process session) to initiate a new HARQ process session.

[87] This is shown in FIG. 3, where a gNB halts initiating any new HARQ process after max-number- HARQ-process. FIG. 3 illustrates two timelines for which time passes to the right: the upper timeline is for the DL and the lower timeline is for the UL. In this example, the gNB sends packets for HARQ processes; the packets 30-1 , 30-2, 30-3 for HARQ processes 1-3 are shown to the left. It will be understood (and as indicated by the ellipsis) that there may be further packets between packet 30-3 and packet 30-max (wherein packet 30-max corresponds to the last HARQ process, i.e. the one that“fills” the HARQ capacity of the WTRU). At one point, the UL includes a first acknowledgement 32 (for packet 30-1 ) that is sent a period of time after the transmission of packet 30-1 , that period of time corresponding to the propagation time T P plus the WTRU processing time T ue . As can be seen from the Figure, while the packet 30-max is sent on the DL after the first acknowledgement 32, the gNB is at this point unaware that the acknowledgement 32 has been sent. This means that after the transmission of the packet 30-max for the last HARQ process, the gNB should not send further packets until it has received and processed and acknowledgement from the WTRU; this is illustrated by block 34, after which the gNB may send a further packet 30-1 which, as the acknowledgement was for HARQ process 1 , corresponds to a new HARQ process 1.

[88] A method 40 for non-terrestrial HARQ management using a configured number of HARQ processes is shown in FIG. 4. In FIG. 4 it is assumed that the calculation for max-number-HARQ-process is done using the above-described BLER target based method.

[89] The method starts in step S41. In step S42, the WTRU calculates max-number-HARQ-process using BLER-Target as already described. The BLER-Target can be a default value or a previously set value.

[90] In step S43, the WTRU sends the thus calculated max-number-HARQ-process to the gNB. In step S44, the WTRU and the gNB operate normally, using max-number-HARQ-process for their operation.

[91] In step S45, the WTRU receives a new BLER-Target from the gNB. In a variant embodiment, the WTRU selects or calculates the new BLER-Target. In step S46, the WTRU calculates a new max-number- HARQ-process using the new BLER-Target as already described and, in step S47, sends the new max-number- HARQ-process to the gNB. The method then returns to step S44, normal operation.

[92] Adaptive BLER-Target method: Broadly speaking, when using the adaptive BLER-Target method, the gNB adapts the BLER-Target in an attempt to ensure that the WTRU HARQ buffer is sufficient for the number of HARQ processes. To this end, the gNB can determine the BLER-Target based on WTRU memory size (i.e. the HARQ buffer), estimated value of propagation delay between gNB and WTRU, a maximum number of transmissions for a packet including retransmissions, and size of the transmission packet. The gNB can receive the WTRU memory size information as part of WTRU Capability Information that is an Radio Resource Control (RRC) message that the WTRU sends to the Network (in most cases during initial registration process).

[93] The gNB can estimate the propagation delay of the transmission to a WTRU for example by halving a round-trip time to the WTRU, by taking the value for the timing advance, by estimating uplink receive timing. The gNB can also estimate the maximum distance to the farthest WTRU in the cell using the altitude of the gNB, its nominal foot print size and its elevation angle and calculate a maximum propagation delay from this maximum distance. Then the gNB can calculate the number of HARQ processes, NHARQ, for example using Equation 1. The optimal value for BLER-Target of a WTRU may then be calculated according to the following:

M rx

BLER-Target = Equation 5 nHARQ N tr M p

[94] In Equation 5, Mrx is memory size of a WTRU, M P is size of transmission packets, and Ntr is the maximum number of transmissions for a packet including retransmissions. Then the gNB configures a WTRU with a BLER-Target, i.e. so that the WTRU aims to operate at and achieve the BLER-Target. The configuration may be performed dynamically through a DCI field, or statically and/or semi-statically by means of RLC configuration. A WTRU then uses the value for BLER-Target for all CSI report operations (such as channel- quality indicator (CQI) calculation) and other such operations that use BLER-Target (Link Adaptation, etc.)

[95] In some embodiments, the calculated value for BLER-Target may be very small and out of an operating range that a telecommunication system is designed for. In this solution, a configuration parameter, min-BLER-Target, may be defined such that, if the calculated value for BLER-Target is less than min-BLER- Target, then a WTRU is configured to use min-BLER-Target for further operation.

[96] A procedure for non-terrestrial HARQ management using the Adaptive BLER-Target method, at the gNB is shown in FIG. 5. A counterpart procedure of a WTRU is shown in FIG. 6.

[97] In FIG. 5, the method starts in step S51. In step S52, the gNB estimates the propagation delay to the WTRU using any suitable method known in the art. In step S53, the gNB uses the estimated propagation delay to calculate a BLER-Target, for example using Equations 1 and 5.

[98] In step S54, the gNB checks if the calculated BLER-Target is lower than a min-BLER-Target. If BLER-Target is greater than min-BLER-Target (“No”), in step S55, the gNB configures the WTRU with the BLER- Target; i.e., the WTRU is configured to operate aiming for BLER-Target. On the other hand, if BLER-Target is lower than min-BLER-Target (“Yes”), in step S56, the gNB configures the WTRU with the min-BLER-Target. The method can then return to step S52 to estimate a new propagation delay and possibly iterate the step until the propagation delay has changed significantly to warrant a new calculation of BLER-Target.

[99] In FIG. 6, the method starts in step S61. In step S62, the WTRU receives BLER-Target from the gNB (typically as a result of step S55 or S56 in FIG. 5) and, if necessary, adapts operation to conform with this configured BLER-Target value. In step S63, the WTRU determines the CQI based on the received BLER- Target and reports, in step S64, the determined CQI to gNB. The method can then iterate from step S62 when the WTRU receives a new BLER-Target from the gNB.

[100] In practice however, the actual number of packet errors and the number of resulting HARQ processes is a random variable. Therefore, the calculation for the appropriate BLER target (e.g., in step S53 of FIG. 5) is preferably based on a stochastic model of the packet errors and the needed reliability, i.e. the probability of not surpassing the limit of the number of HARQ processes.

[101] One approach is to assume a Poisson arrival model for the occurrence of the packet errors. In this model, it is assumed that the number of maximum available HARQ processes is a given parameter, N HARQ , and that the number of packets N paCk e t in one HARQ period is: Equation 6

where 77 is the total time between sending a packet by a gNB and receiving ACK/NACK feedback and T Sf is the subframe duration. [102] Then, assuming the Poisson model for the arrival of packet errors, the number of packet errors in the HARQ period is a Poisson random variable and the probability of having k packet errors is: Equation 7

where m = BLER. N paCk e t and is the average number of packet errors in the HARQ period T t . Under these assumptions, the probability of HARQ blockage, i.e. the probability that the number of required HARQ processes surpasses the maximum number of available HARQ processes, N HARQ , may be calculated as: Equation 8

[103] Based on this formula, for a given reliability level for HARQ process, or equivalently a given probability of HARQ blockage, a gNB may determine the optimum BLER-Target and may use a method similar to the method described with reference to FIG. 5 based on this calculation.

[104] In one embodiment, a gNB may determine whether to either disable or enable the HARQ operation with retransmission. This means that, if the HARQ operation with retransmission is disabled, for the transmission of a packet, only the first transmission is performed. If the first transmission fails, there may not be any further MAC layer retransmission. To recover the failed packet, further retransmission(s) are performed through ARQ operation in higher layers. A decision for disabling/enabling HARQ operation may be made based on WTRU memory class, or propagation delay, or network type (or a combination of two or more of these) as:

[105] WTRU memory class: If a WTRU memory size is not sufficient to handle the maximum number of HARQ processes, then the gNB may decide to disable the HARQ process retransmission for that WTRU.

[106] Propagation delay: If the estimated propagation delay is so large that the required WTRU memory size is larger than the actual WTRU memory size, then gNB may decide to disable the HARQ process retransmission for a WTRU.

[107] Network type: If a gNB belongs to a Non-Terrestrial Network, it may totally disable HARQ process retransmission for all UEs associated with the gNB. In such a case, signaling for disabling HARQ is broadcast to all UEs through system information in a broadcast channel.

[108] Disabling HARQ operation may be issued by the gNB (or Network) by sending a signal or a collection of signals, hereafter called disable-HARQ, through either broadcast channel, or RRC configuration, or L1 DCI signaling, or a combination of RRC configuration and L1 DCI signaling. Disabling HARQ may be done explicitly or implicitly. Once a WTRU receives disable-HARQ, then upon receiving a non-decodable packet, the WTRU discards the packet without storing it in its memory for further HARQ combining, and simply sends NACK feedback to the gNB. Disable-HARQ may be sent to WTRU(s) using any of the following embodiments. [109] In one embodiment, a HARQ process number may be greater than the number of HARQ processes, for example configured by the gNB. In this embodiment a WTRU is configured with a small value, e.g. 2, for the“number of HARQ processes” in RRC configuration. Then during scheduling, the gNB may set the “HARQ process number” field in DCI to any value greater than the value for the number of HARQ processes in RRC configuration, e.g. 16. This way, a WTRU implicitly interprets that the HARQ operation is disabled for the received packet.

[1 10] In one embodiment, a semi-static configuration by RRC may be used by a WTRU. In this embodiment the number of HARQ processes is configured in RRC to 0 for a WTRU. This way a WTRU explicitly interprets that, for all receiving packets, the HARQ operation is disabled. The embodiment implies that in NR the existing set of integers for the number of HARQ processes, i.e. {2, 4, 6, 8, 10, 12, 16}, is extended to a new set of {0, 2, 4, 6, 8, 10, 12, 16}.

[1 1 1] In this embodiment, a new identifier HARQ cell radio-network temporary identifier (C-RNTI) is defined. HARQ C-RNTI identifies grants or assignments with disabled HARQ. HARQ C-RNTI is a dedicated RNTI and is configured by RRC. The gNB configures a WTRU with a HARQ C-RNTI as part of RRC configuration. The CRC parity bits obtained for the PDCCH payload are scrambled with the HARQ C-RNTI for HARQ disable/enable.

[1 12] A dynamic indication may be indicated by DCI. For HARQ disable/enable in downlink, DCI Formats 1_0 and 1_1 , with PDCCH’s CRC scrambled by HARQ C-RNTI, may be used. A bit field in those DCI formats may then be used to disable/enable HARQ. The bit field may be chosen from the available HARQ related fields such as“new data indicator”,“redundancy version”, and“HARQ process number”.

[1 13] A WTRU may choose to disable HARQ operation for transport blocks (TBs) or code block groups (CBGs) that exceed a maximum size, namely max-HARQ-size. In accordance with this feature, a WTRU may first calculate a WTRU-specific value for max-HARQ-size. The calculation may be based on the WTRU’s memory size and the propagation delay to the serving gNB. The information of the propagation delay to the serving gNB may be extracted from the timing advance information already received by the WTRU in a random access response (RAR) during a random access procedure. Once the WTRU calculates the value for max-HARQ-size, which can ensure that all packets to be used in HARQ processes fit in allotted HARQ memory, it may then send this value to the network or serving gNB as a part of a WTRU capability information element (IE) that is an RRC message.

[1 14] When a gNB is scheduling a TB (or CBG) for transmission to a WTRU, if the size of the TB (or CBG) is larger than max-HARQ-size, then the gNB assumes that the HARQ operation for that TB (or CBG) is disabled. [1 15] FIG. 7 illustrates a WTRU procedure for non-terrestrial HARQ management using WTRU- specific selective Disable/Enable HARQ in accordance with an exemplary embodiment.

[1 16] The method 70 starts in step S71. In step S72, the WTRU estimates the propagation delay using for example available timing advance information and, in step S73, calculates max-HARQ-size using the estimated propagation delay and the memory size of the WTRU, after which the max-HARQ-size is sent, in step S74, to the gNB.

[1 17] In step S75, the WTRU receives a TB or CBG from the gNB, and checks, in step S76, if the size of the TB or CBG is greater than max-HARQ-size.

[1 18] If the size of the TB or CBG is not greater than max-HARQ-size (“No”), in step S77, the WTRU treats the TB or CBG as a transmission for which HARQ is enabled and stores the TB or CBG in its HARQ buffer.

[1 19] On the other hand, if the size of the TB or CBG is greater than max-HARQ-size (‘Yes”), in step S78, the WTRU treats the TB or CBG as a transmission for which HARQ is disabled and does not store the TB or CBG.

[120] In one embodiment, if the WTRU is configured with higher layer parameter CBG-DL = ON (i.e., the WTRU is expected to receive PDSCHs that include code block groups (CBGs) of a transport block), the WTRU may also be configured with higher layer parameter for autonomous disable/enable HARQ. In this case, the WTRU may autonomously decide to disable or enable the HARQ operation for a given HARQ process number based on the WTRU memory size and/or the WTRU capability/category.

[121] In case the WTRU fails to correctly decode a large number of CBGs which comprise a TB, it implies that the WTRU may need to keep a large amount of information in memory for a given HARQ process to be able to combine it with the subsequent retransmissions of a TB or CBG. For this scenario, if the number of NACKs for CBGs of a transport block is greater than a certain threshold value, the WTRU may first autonomously disable the HARQ and flush out the memory. Then, the WTRU may generate the HARQ-NACK information bit for the entire TB or each CBG regardless of whether the WTRU has correctly decoded all code blocks of one or more CBG(s). In one example, the WTRU transmits a binary zero for a TB or all zeros for all CBGs on the PUCCH or PUSCH. By transmitting the HARQ-NACK information for a TB or all CBGs, the WTRU may implicitly indicate to the gNB that the HARQ operation is autonomously disabled by the WTRU and the associated HARQ process has been terminated from the perspective of the WTRU. Accordingly, the gNB may retransmit the initial transmission using the ARQ mechanism.

[122] If the number of NACKs for CBGs of a transport block is smaller than a certain threshold value, it implies that the WTRU may have sufficient memory to keep the decoded information for the failed CBG(s) to be used by the WTRU for combining with the subsequent retransmissions of a TB or CBG. Therefore, the WTRU may enable HARQ for a given HARQ process number and generate the HARQ-ACK information in the form of a HARQ-ACK codebook and transmit it to the gNB on the PUCCH or PUSCH. The WTRU implicitly indicates to the gNB that the HARQ operation is enabled by transmitting a combination of binary 1 s and Os as part of the HARQ-ACK information.

[123] The WTRU may determine the threshold for autonomous disable/enable HARQ function based on its memory size, WTRU capability, WTRU category, etc.

[124] FIG. 8 illustrates an exemplary WTRU procedure for the autonomous disable/enable of HARQ by the WTRU.

[125] The method in FIG. 8 starts in step S81. In step S82, the WTRU receives from the gNB (or Network) a parameter enabling the WTRU to disable/enable HARQ autonomously. In step S83, the WTRU calculates a threshold for HARQ disabling based on, for example, the memory size of the WTRU, the capability of the WTRU, the category of the WTRU, or a combination of at least two of these.

[126] In step S84, the WTRU decodes all CBGs that include a TB for a given HARQ process number. During the decoding, the WTRU will send NACKs for CBGs that are received incorrectly; the WTRU counts the number of NACKs sent for the given HARQ process number. In step S85, the WTRU checks if the number of sent NACKs exceeds a threshold value that can be a default value or configured by the gNB or the WTRU.

[127] In case the number of sent NACKs does not exceed the threshold value (“No”), in step S86, the WTRU enables the HARQ process and stores the decoded information for received incorrect CBGs in memory and, in step S87, indicates implicitly to the gNB that HARQ is enabled for the HARQ process by generating binary and Ό’ for the HARQ-ACK information, as already described.

[128] Conversely, in case the number of sent NACKs exceeds the threshold value (“No”), in step S88, the WTRU disables the HARQ process and flushes the memory for the given HARQ process and, in step S89, indicates implicitly to the gNB that HARQ is disabled for the HARQ process by generating all binary Ό’ for the HARQ-ACK information, as already described.

[129] In an embodiment, a WTRU may determine and indicate the maximum TBS to the gNB. In an embodiment, a WTRU may employ an adaptive soft state buffer management protocol. In this embodiment, a

WTRU supporting non-terrestrial networks may determine and adapt the parameters related to its supported soft buffer and indicate them to the gNB through UL signaling. In one example, a WTRU may determine and indicate to the gNB the maximum TBS that it may support based on soft buffer size, or WTRU capability, or a combination of these. The WTRU may determine a calculated maximum TBS based on the expected Round Trip Time (RTT) of the transmission and then select an identified maximum TBS among the NR TBS coded sizes smaller than the largest TBS defined in NR. The RTT depends on the distance to and thus typically on the type of the airborne

(e.g., High Altitude UAS Platforms (HAPs)) or spaceborne (e.g., Satellites (LEO, MEO, GEO)) vehicles. The

WTRU may determine the RTT implicitly or explicitly through signaling in system information. For larger RTTs, the WTRU could use a smaller maximum TBS and for smaller RTTs, the WTRU could use a larger maximum TBS size. The WTRU may also use the maximum configured HARQ processes in calculating the maximum TBS to apply. If the WTRU is configured with a larger number of HARQ processes, the WTRU could use a smaller maximum TBS and, for smaller number of HARQ processes, the WTRU could use a larger maximum TBS. The relationship between the number of HARQ processes, RTTs and the maximum TBS can also be predefined and specified.

[130] FIG. 9 illustrates an exemplary method 90 of determination and indication of the maximum TBS- size. The method starts in step S91. In step S92, the WTRU can estimate the propagation delay, which it uses, in step S93, to determine the maximum RTT. As already described, max-RTT can also be determined using signaling in system information.

[131] In step S94, the WTRU calculates max-TBS, for example based on max-number-HARQ- processes, as described and, in step S95, sends the max-TBS to the gNB.

[132] A WTRU can also determine and indicate the rate for the limited buffer rate matching (LBRM) to the gNB. In an example, a WTRU may determine and indicate to the gNB its supported rate for the limited buffer rate matching (LBRM) per HARQ process. The WTRU can estimate the RTT from its timing advance or from information about gNB altitude, nominal foot print size, and the elevation angle. The WTRU can then select an arbitrary threshold value for buffer reduction factor, for example 1/2, which can yield an effective mother code rate of 2/3. For larger RTTs, the WTRU could apply a higher coding rate than the buffer reduction factor 1/2 for the rate of the LBRM per HARQ process. This way, the effective mother code rate can be greater than 2/3. Similarly, for smaller RTTs, the WTRU could apply a smaller coding rate than 1/2 for the rate of the LBRM per HARQ process. This way, the effective mother code rate can be smaller than 2/3. The WTRU may also use the maximum configured HARQ processes to calculate the coding rate for LBRM. If the WTRU is configured with a larger number of HARQ processes, it could apply a higher coding rate for LBRM and for smaller number of HARQ processes, the WTRU could apply a smaller coding rate.

[133] FIG. 10 illustrates a method 1000 for WTRU LBRM determination and indication. The method starts in step 1001. In step S1002, the WTRU estimates the propagation delay and determines, in step S1003, max-RTT, for example as described herein with reference to FIG. 9.

[134] In step S1004, the WTRU calculates the LBRM rate, as already described, and, in step S1005, sends the LBRM rate to the gNB.

[135] In an embodiment, the WTRU can determine and indicate to the gNB both the maximum TBS and the rate for the limited buffer rate matching (LBRM). In an example, a WTRU may determine and signal an index to a combination of the maximum supported TBS and the rate for the limited buffer rate matching per HARQ process to the gNB. The WTRU may indicate an index to the gNB from which the gNB determines both maximum supported TBS and the rate for the limited buffer rate matching.

[136] A WTRU may receive the maximum TBS and the rate for the limited buffer rate matching (LBRM) per HARQ process through RRC configuration for cellular NR and then determine the same values for NTN based on the satellite type. In one example, when the WTRU expects a transmission from a LEO satellite constellation, the WTRU may determine through higher layer signaling that the maximum TBS is half of the maximum TBS defined in NR and the rate for the LBRM per HARQ process is at 2/3 rather than 1/2, as would be the case for cellular NR (for which the RTT can be considered negligible). In another example, when the WTRU expects a transmission from a MEO satellite constellation, the WTRU may determine through higher layer signaling that the maximum TBS is 1/3 of the maximum TBS defined in NR and the rate for the LBRM per HARQ process is at 3/4 rather than 1/2.

[137] FIG. 11 illustrates a method 1 100 for WTRU determination and indication of max-TBS and LBRM. The method starts in step S1101. In step S1 102, the WRTU receives RRC configuration for NTN communication.

[138] In step S1 103, the WTRU determines max-RTT, as described, and, in step S1 104, calculates both max-TBS and LBRM rate, as also described.

[139] In step S1 104, the WTRU sends the calculated max-TBS and LBRM rate to gNB. This information can be sent using an index that for example can enable the gNB to use a look-up table to determine the max-TBS and LBRM rate.

CONCLUSION

[140] 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 non-transitory computer-readable storage media include, but are not limited to, a read only memory (ROM), 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 102, UE, terminal, base station, RNC, or any host computer. [141] Moreover, in the embodiments described above, processing platforms, computing systems, controllers, and other devices containing processors are noted. These devices may contain at least one Central Processing Unit ("CPU") and memory. In accordance with the practices of persons skilled in the art of computer programming, reference to acts and symbolic representations of operations or instructions may be performed by the various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer executed" or "CPU executed."

[142] One of ordinary skill in the art will appreciate that the acts and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. An electrical system represents data bits that can cause a resulting transformation or reduction of the electrical signals and the maintenance of data bits at memory locations in a memory system to thereby reconfigure or otherwise alter the CPU's operation, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to or representative of the data bits. It should be understood that the representative embodiments are not limited to the above-mentioned platforms or CPUs and that other platforms and CPUs may support the provided methods.

[143] The data bits may also be maintained on a computer readable medium including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory ("RAM")) or non-volatile (e.g., Read-Only Memory ("ROM")) mass storage system readable by the CPU. The computer readable medium may include cooperating or interconnected computer readable medium, which exist exclusively on the processing system or are distributed among multiple interconnected processing systems that may be local or remote to the processing system. It is understood that the representative embodiments are not limited to the above-mentioned memories and that other platforms and memories may support the described methods.

[144] In an illustrative embodiment, any of the operations, processes, etc. described herein may be implemented as computer-readable instructions stored on a computer-readable medium. The computer- readable instructions may be executed by a processor of a mobile unit, a network element, and/or any other computing device.

[145] There is little distinction left between hardware and software implementations of aspects of systems. The use of hardware or software is generally (e.g., but not always, in that in certain contexts the choice between hardware and software may become significant) a design choice representing cost vs. efficiency tradeoffs. There may be various vehicles by which processes and/or systems and/or other technologies described herein may be affected (e.g., hardware, software, and/or firmware), and the preferred vehicle may vary with the context in which the processes and/or systems and/or other technologies are deployed. For example, if an implementer determines that speed and accuracy are paramount, the implementer may opt for a mainly hardware and/or firmware vehicle. If flexibility is paramount, the implementer may opt for a mainly software implementation. Alternatively, the implementer may opt for some combination of hardware, software, and/or firmware.

[146] The foregoing detailed description has set forth various embodiments of the devices and/or processes via the use of block diagrams, flowcharts, and/or examples. Insofar as such block diagrams, flowcharts, and/or examples contain one or more functions and/or operations, it will be understood by those within the art that each function and/or operation within such block diagrams, flowcharts, or examples may be implemented, individually and/or collectively, by a wide range of hardware, software, firmware, or virtually any combination thereof. Suitable processors include, by way of example, 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), Application Specific Standard Products (ASSPs); Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine.

[147] Although features and elements are provided 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. The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations may be made without departing from its spirit and scope, as will be apparent to those skilled in the art. No element, act, or instruction used in the description of the present application should be construed as critical or essential to the invention unless explicitly provided as such. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those enumerated herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. The present disclosure is to be limited only by the terms of the appended claims, along with the full scope of equivalents to which such claims are entitled. It is to be understood that this disclosure is not limited to particular methods or systems.

[148] It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting. As used herein, when referred to herein, the terms“station” and its abbreviation“STA”, "user equipment" and its abbreviation "UE" may mean (i) a wireless transmit and/or receive unit (WTRU), such as described infra; (ii) any of a number of embodiments of a WTRU, such as described infra; (iii) a wireless-capable and/or wired-capable (e.g., tetherable) device configured with, inter alia, some or all structures and functionality of a WTRU, such as described infra; (iii) a wireless-capable and/or wired-capable device configured with less than all structures and functionality of a WTRU, such as described infra; or (iv) the like. Details of an example WTRU, which may be representative of (or interchangeable with) any UE recited herein, are provided below with respect to FIGS. 1A-1 D. [149] In certain representative embodiments, several portions of the subject matter described herein may be implemented via Application Specific Integrated Circuits (ASICs), Field Programmable Gate Arrays (FPGAs), digital signal processors (DSPs), and/or other integrated formats. Flowever, those skilled in the art will recognize that some aspects of the embodiments disclosed herein, in whole or in part, may be equivalently implemented in integrated circuits, as one or more computer programs running on one or more computers (e.g., as one or more programs running on one or more computer systems), as one or more programs running on one or more processors (e.g., as one or more programs running on one or more microprocessors), as firmware, or as virtually any combination thereof, and that designing the circuitry and/or writing the code for the software and or firmware would be well within the skill of one of skill in the art in light of this disclosure. In addition, those skilled in the art will appreciate that the mechanisms of the subject matter described herein may be distributed as a program product in a variety of forms, and that an illustrative embodiment of the subject matter described herein applies regardless of the particular type of signal bearing medium used to actually carry out the distribution. Examples of a signal bearing medium include, but are not limited to, the following: a recordable type medium such as a floppy disk, a hard disk drive, a CD, a DVD, a digital tape, a computer memory, etc., and a transmission type medium such as a digital and/or an analog communication medium (e.g., a fiber optic cable, a waveguide, a wired communications link, a wireless communication link, etc.).

[150] The herein described subject matter sometimes illustrates different components contained within, or connected with, different other components. It is to be understood that such depicted architectures are merely examples, and that in fact many other architectures may be implemented which achieve the same functionality. In a conceptual sense, any arrangement of components to achieve the same functionality is effectively "associated" such that the desired functionality may be achieved. Flence, any two components herein combined to achieve a particular functionality may be seen as "associated with" each other such that the desired functionality is achieved, irrespective of architectures or intermediate components. Likewise, any two components so associated may also be viewed as being "operably connected", or "operably coupled", to each other to achieve the desired functionality, and any two components capable of being so associated may also be viewed as being "operably couplable" to each other to achieve the desired functionality. Specific examples of operably couplable include but are not limited to physically mateable and/or physically interacting components and/or wirelessly interactable and/or wirelessly interacting components and/or logically interacting and/or logically interactable components.

[151] With respect to the use of substantially any plural and/or singular terms herein, those having skill in the art can translate from the plural to the singular and/or from the singular to the plural as is appropriate to the context and/or application. The various singular/plural permutations may be expressly set forth herein for sake of clarity. [152] It will be understood by those within the art that, in general, terms used herein, and especially in the appended claims (e.g., bodies of the appended claims) are generally intended as "open" terms (e.g., the term "including" should be interpreted as "including but not limited to," the term "having" should be interpreted as "having at least," the term "includes" should be interpreted as "includes but is not limited to," etc.). It will be further understood by those within the art that if a specific number of an introduced claim recitation is intended, such an intent will be explicitly recited in the claim, and in the absence of such recitation no such intent is present. For example, where only one item is intended, the term "single" or similar language may be used. As an aid to understanding, the following appended claims and/or the descriptions herein may contain usage of the introductory phrases "at least one" and "one or more" to introduce claim recitations. However, the use of such phrases should not be construed to imply that the introduction of a claim recitation by the indefinite articles "a" or "an" limits any particular claim containing such introduced claim recitation to embodiments containing only one such recitation, even when the same claim includes the introductory phrases "one or more" or "at least one" and indefinite articles such as "a" or "an" (e.g., "a" and/or "an" should be interpreted to mean "at least one" or "one or more"). The same holds true for the use of definite articles used to introduce claim recitations. In addition, even if a specific number of an introduced claim recitation is explicitly recited, those skilled in the art will recognize that such recitation should be interpreted to mean at least the recited number (e.g., the bare recitation of "two recitations," without other modifiers, means at least two recitations, or two or more recitations).

[153] Furthermore, in those instances where a convention analogous to "at least one of A, B, and C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, and C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). In those instances where a convention analogous to "at least one of A, B, or C, etc." is used, in general such a construction is intended in the sense one having skill in the art would understand the convention (e.g., "a system having at least one of A, B, or C" would include but not be limited to systems that have A alone, B alone, C alone, A and B together, A and C together, B and C together, and/or A, B, and C together, etc.). It will be further understood by those within the art that virtually any disjunctive word and/or phrase presenting two or more alternative terms, whether in the description, claims, or drawings, should be understood to contemplate the possibilities of including one of the terms, either of the terms, or both terms. For example, the phrase "A or B" will be understood to include the possibilities of "A" or "B" or "A and B." Further, the terms "any of followed by a listing of a plurality of items and/or a plurality of categories of items, as used herein, are intended to include "any of," "any combination of," "any multiple of," and/or "any combination of multiples of" the items and/or the categories of items, individually or in conjunction with other items and/or other categories of items. Moreover, as used herein, the term "set" or“group” is intended to include any number of items, including zero. Additionally, as used herein, the term "number" is intended to include any number, including zero.

[154] In addition, where features or aspects of the disclosure are described in terms of Markush groups, those skilled in the art will recognize that the disclosure is also thereby described in terms of any individual member or subgroup of members of the Markush group.

[155] As will be understood by one skilled in the art, for any and all purposes, such as in terms of providing a written description, all ranges disclosed herein also encompass any and all possible subranges and combinations of subranges thereof. Any listed range can be easily recognized as sufficiently describing and enabling the same range being broken down into at least equal halves, thirds, quarters, fifths, tenths, etc. As a non-limiting example, each range discussed herein may be readily broken down into a lower third, middle third and upper third, etc. As will also be understood by one skilled in the art all language such as "up to," "at least," "greater than," "less than," and the like includes the number recited and refers to ranges which can be subsequently broken down into subranges as discussed above. Finally, as will be understood by one skilled in the art, a range includes each individual member. Thus, for example, a group having 1 -3 cells refers to groups having 1 , 2, or 3 cells. Similarly, a group having 1 -5 cells refers to groups having 1 , 2, 3, 4, or 5 cells, and so forth.

[156] Moreover, the claims should not be read as limited to the provided order or elements unless stated to that effect. In addition, use of the terms "means for" in any claim is intended to invoke 35 U.S.C. §112, H 6 or means-plus-function claim format, and any claim without the terms "means for" is not so intended.

[157] A processor in association with software may be used to implement a radio frequency transceiver for use in a wireless transmit receive unit (WTRU), user equipment (UE), terminal, base station, Mobility Management Entity (MME) or Evolved Packet Core (EPC), or any host computer. The WTRU may be used m conjunction with modules, implemented in hardware and/or software including a Software Defined Radio (SDR), and other components such as a camera, a video camera module, a videophone, a speakerphone, a vibration device, a speaker, a microphone, a television transceiver, a hands free headset, a keyboard, a Bluetooth® module, a frequency modulated (FM) radio unit, a Near Field Communication (NFC) Module, a liquid crystal display (LCD) display unit, an organic light-emitting diode (OLED) display unit, a digital music player, a media player, a video game player module, an Internet browser, and/or any Wireless Local Area Network (WLAN) or Ultra Wide Band (UWB) module.

[158] Although the invention has been described in terms of communication systems, it is contemplated that the systems may be implemented in software on microprocessors/general purpose computers

(not shown). In certain embodiments, one or more of the functions of the various components may be implemented in software that controls a general-purpose computer. [159] In addition, although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.

[160] Throughout the disclosure, one of skill understands that certain representative embodiments may be used in the alternative or in combination with other representative embodiments.

[161] 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 non-transitory computer-readable storage media include, but are not limited to, a read only memory (ROM), 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 WRTU, UE, terminal, base station, RNC, or any host computer.

[162] Moreover, in the embodiments described above, processing platforms, computing systems, controllers, and other devices containing processors are noted. These devices may contain at least one Central Processing Unit ("CPU") and memory. In accordance with the practices of persons skilled in the art of computer programming, reference to acts and symbolic representations of operations or instructions may be performed by the various CPUs and memories. Such acts and operations or instructions may be referred to as being "executed," "computer executed" or "CPU executed."

[163] One of ordinary skill in the art will appreciate that the acts and symbolically represented operations or instructions include the manipulation of electrical signals by the CPU. An electrical system represents data bits that can cause a resulting transformation or reduction of the electrical signals and the maintenance of data bits at memory locations in a memory system to thereby reconfigure or otherwise alter the CPU's operation, as well as other processing of signals. The memory locations where data bits are maintained are physical locations that have particular electrical, magnetic, optical, or organic properties corresponding to or representative of the data bits.

[164] The data bits may also be maintained on a computer readable medium including magnetic disks, optical disks, and any other volatile (e.g., Random Access Memory ("RAM")) or non-volatile ("e.g., Read-Only

Memory ("ROM")) mass storage system readable by the CPU. The computer readable medium may include cooperating or interconnected computer readable medium, which exist exclusively on the processing system or are distributed among multiple interconnected processing systems that may be local or remote to the processing system. It is understood that the representative embodiments are not limited to the above-mentioned memories and that other platforms and memories may support the described methods.

[165] Suitable processors include, by way of example, 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), Application Specific Standard Products (ASSPs); Field Programmable Gate Arrays (FPGAs) circuits, any other type of integrated circuit (IC), and/or a state machine.

[166] Although the invention has been described in terms of communication systems, it is contemplated that the systems may be implemented in software on microprocessors/general purpose computers (not shown). In certain embodiments, one or more of the functions of the various components may be implemented in software that controls a general-purpose computer.

[167] In addition, although the invention is illustrated and described herein with reference to specific embodiments, the invention is not intended to be limited to the details shown. Rather, various modifications may be made in the details within the scope and range of equivalents of the claims and without departing from the invention.