CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This claims the benefit of U.S. Provisional Patent Application Serial No. 62/545,869, filed August 15, 2017, which are incorporated by reference as if fully set forth.

BACKGROUND

[0002] In IEEE 802.11 devices operating in a wireless local area network (WLAN), the

Media Access Control (MAC) layer communicates with the Physical (PHY) Layer Convergence Protocol sublayer (PLCP) via primitives (a set of "instructive commands" or "fundamental instructions" through a service access point (SAP). When the MAC layer instructs it to do so, the PLCP prepares MAC protocol data units (MPDUs) for transmission. The PLCP minimizes the dependence of the MAC layer on the PMD sublayer by mapping MPDUs into a frame format suitable for transmission by the PMD. The PLCP also delivers incoming frames from the wireless medium to the MAC layer.

[0003] In addition, the PLCP appends a PHY-specific preamble and header fields to the

MPDU that contain information needed by the Physical layer transmitters and receivers. The 802.11 standard refers to this composite frame (the MPDU with an additional PLCP preamble and header) as a PLCP protocol data unit (PPDU). The MPDU is also called the PLCP Service Data Unit (PSDU), and is typically referred to as such when referencing physical layer operations. The frame structure of a PPDU provides for asynchronous transfer of PSDUs between stations. As a result, the receiving station's Physical layer must synchronize its circuitry to each individual incoming frame.

[0004] In wireless communications systems, particularly in millimeter wave (mmW) communications, it is desirable to use waveforms with low peak-to-average power ratio (PAPR) for the fields (e.g., trails, preambles, or reference symbols, channel estimation field (CEF), demodulation reference signal (DMRS), or training (TRN) fields) to increase channel estimation accuracy or the coverage range in beam training periods. Typically, these fields are generated through fixed sequences, e.g., Golay sequences or Frank-David-Zadoff-Chu (ZC) sequences. While ZC sequences are not ultra-low PAPR (ULP) sequences, Golay sequence are ULP sequences. However, a general construction rule which enumerates all of the Golay sequences with a restricted alphabet, e.g., {+1 , -1 , j, -j}, and different lengths, is not known and the known ones have the length of 2 ^x 10 ^y 26 ^z , which introduces constraints in a practical orthogonal frequency-division multiplexing (OFDM) systems. In addition, in some cases, it may be desirable to insert zero tones between the elements of the sequence to achieve a low-complexity receiver, frequency diversity, or DC tone insertions. Methods for ULP sequence generation which allow for zero tones and flexible density and length are desired for practical OFDM systems (e.g., CEF and TRN field of OFDM PHY in IEEE 802.1 lay).

[0005] Another problem associated with ULP sequences is the spatial mapping of the sequences. For example, in IEEE 802.1 l ay, 8 spatial streams are supported. However, in order to avoid unintentional beamforming, the correlation between the spatial streams should be low. On the other hand, the sequences generated with ULP sequences should also have a set a limited alphabet.

[0006] In some communication systems, e.g., 3GPP 5G New Radio (NR), some specific channels, e.g., PUCCH, may need to use sequences to modulate some messages, e.g., acknowledgement (ACK), negative acknowledgement (NACK), or scheduling request (SR), with low PAPR. However, typically, it is challenging to construct sequences with low PAPR, particularly, when multiple messages are mapped into frequency and/or frequency diversity is needed.

SUMMARY

[0007] Methods, apparatuses and systems are provided for generating ultra-low peak-to- average power ratio (PAPR) (ULP) sequences. A wireless transmit/receive unit (WTRU) may generate a pair of complementary Golay sequences a and b. A sum of a direct autocorrelation function of each sequence of the pair of complementary Golay sequences is zero when the length of the sequences a and b is non-zero. The WTRU encodes data intended for transmission to a gNode-B with at least one of the pair of complementary Golay sequences. The WTRU processes the encoded data using an inverse discrete fourier transform (IDFT) and transmits an orthogonal frequency division multiplex (OFDM) signal including the transformed encoded data.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] 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:

[0009] FIG. 1A is a system diagram illustrating an example communications system in which one or more disclosed embodiments may be implemented;

[0010] 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; [0011] 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. 1A according to an embodiment;

[0012] 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;

[0013] FIG. 2 shows an example of an enhanced directional multi-gigabit (EDMG) PPDU format according to one or more embodiments;

[0014] FIG. 3 illustrates a block diagram of a method for generating ULP sequences using an upsampling operation according to one or more embodiments;

[0015] FIG. 4 illustrates a block diagram of a method for generating ULP sequences using an SAS operation according to one or more embodiments;

[0016] FIG. 5 illustrates a diagram of a method for generating ULP sequences using upsampling and staggering operations according to one or more embodiments;

[0017] FIG. 6 illustrates a block diagram of a method of OFDM generation with an ULP sequence according to one or more embodiments;

[0018] FIG. 7 shows a block diagram of a method of ULP sequence generation using DFT loops according to one or more embodiments;

[0019] FIG. 8, corresponding to Table 4, illustrates PAPR results corresponding to the ULP sequences generated via the method illustrated in FIG. 7 and conventional EDMG-EDMG-CEF OFDM sequences;

[0020] FIG. 9, corresponding to Table 5, illustrates PAPR results corresponding to the ULP sequences generated via the method illustrated in FIG. 7 and conventional EDMG-EDMG-CEF OFDM sequences;

[0021] FIG. 10, corresponding to Table 6, illustrates PAPR results corresponding to the

ULP sequences generated via the method illustrated in FIG. 7 and conventional EDMG-EDMG-CEF OFDM sequences;

[0022] FIG. 11 , corresponding to Table 7, illustrates PAPR results corresponding to the

ULP sequences generated via the method illustrated in FIG. 7 and conventional EDMG-EDMG-CEF OFDM sequences;

[0023] FIG. 12 illustrates various applications of sequence-based messaging using Golay sequences according to one or more embodiments;

[0024] FIGS. 13 illustrates block diagrams of different methods for low PAPR (<3dB) short

PUCCH with 1-2 bits by using Golay complementary pairs according to one or more embodiments; [0025] FIG. 14 illustrates a block diagram of ULP generation methodology according to one or more embodiments;

[0026] FIG. 15 illustrates PAPR performance results for short PUCCH methods according to one or more embodiments; and

[0027] FIG. 16 is a method diagram of a method for transmitting information using a pair of complementary Golay sequences.

DETAILED DESCRIPTION

[0028] 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 discrete Fourier transform Spread OFDM (ZT UW DTS-s OFDM), unique word OFDM (UW-OFDM), resource block-filtered OFDM, filter bank multicarrier (FBMC), and the like.

[0029] As shown in FIG. 1A, the communications system 100 may include wireless transmit/receive units (WTRUs) 102a, 102b, 102c, 102d, a RAN 104/113, a CN 106/1 15, a public switched telephone network (PSTN) 108, the Internet 110, and other networks 112, 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.

[0030] The communications systems 100 may also include a base station 1 14a and/or a base station 114b. Each of the base stations 114a, 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 106/1 15, the Internet 110, and/or the other networks 1 12. By way of example, the base stations 114a, 1 14b may be a base transceiver station (BTS), a Node-B, an eNode B, a Home Node B, a Home eNode B, a next generation (gNB), a new radio (NR) NodeB, a site controller, an access point (AP), a wireless router, and the like. While the base stations 114a, 114b are each depicted as a single element, it will be appreciated that the base stations 114a, 114b may include any number of interconnected base stations and/or network elements.

[0031] The base station 1 14a may be part of the RAN 104/113, 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 114a may be divided into three sectors. Thus, in one embodiment, the base station 114a may include three transceivers, i.e., one for each sector of the cell. In an embodiment, the base station 114a may employ multiple-input multiple output (MIMO) technology and may utilize multiple transceivers for each sector of the cell. For example, beamforming may be used to transmit and/or receive signals in desired spatial directions.

[0032] The base stations 114a, 114b may communicate with one or more of the WTRUs

102a, 102b, 102c, 102d over a respective 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 1 16 may be established using any suitable radio access technology (RAT).

[0033] 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 104/113 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 a respective air interface 1 16 using wideband CDMA (WCDMA). WCDMA may include communication protocols such as High-Speed Packet Access (HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed Downlink (DL) Packet Access (HSDPA) and/or High- Speed Uplink (UL) Packet Access (HSUPA).

[0034] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as Evolved UMTS Terrestrial Radio Access (E-UTRA), which may establish a respective air interface 116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A) and/or LTE-Advanced Pro (LTE-A Pro).

[0035] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement a radio technology such as NR Radio Access, which may establish a respective air interface 116 using NR.

[0036] In an embodiment, the base station 114a and the WTRUs 102a, 102b, 102c may implement multiple radio access technologies. For example, the base station 114a and the WTRUs 102a, 102b, 102c may implement LTE radio access and NR radio access together, for instance using dual connectivity 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).

[0037] In other embodiments, the base station 114a and the WTRUs 102a, 102b, 102c may implement radio technologies such as IEEE 802.11 (i.e., Wireless Fidelity (WiFi), IEEE 802.16 (i.e., Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000, CDMA2000 1X, CDMA2000 Evolution Data Only/Evolution Data Optimized (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.

[0038] The base station 114b in FIG. 1A may be a wireless router, Home Node B, Home eNode B, or access point, for example, and may utilize any suitable RAT for facilitating wireless connectivity in a localized area, such as a place of business, a home, a vehicle, a campus, an industrial facility, an air corridor (e.g., for use by drones), a roadway, and the like. In one embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.11 to establish a wireless local area network (WLAN). In an embodiment, the base station 114b and the WTRUs 102c, 102d may implement a radio technology such as IEEE 802.15 to establish a wireless personal area network (WPAN). In yet another embodiment, the base station 114b and the WTRUs 102c, 102d may utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE, LTE-A, LTE-A Pro, NR etc.) to establish a picocell or femtocell. As shown in FIG. 1A, the base station 114b may have a direct connection to the Internet 110. Thus, the base station 1 14b may not be required to access the Internet 110 via the CN 106/115.

[0039] The RAN 104/1 13 may be in communication with the CN 106/1 15, 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 106/115 may provide call control, billing services, mobile location-based services, pre-paid calling, Internet connectivity, video distribution, etc., and/or perform high-level security functions, such as user authentication. Although not shown in FIG. 1A, it will be appreciated that the RAN 104/113 and/or the CN 106/115 may be in direct or indirect communication with other RANs that employ the same RAT as the RAN 104/113 or a different RAT. For example, in addition to being connected to the RAN 104/113, which may be utilizing a NR radio technology, the CN 106/115 may also be in communication with another RAN (not shown) employing a GSM, UMTS, CDMA 2000, WiMAX, E-UTRA, or WiFi radio technology.

[0040] The CN 106/115 may also serve as a gateway for the WTRUs 102a, 102b, 102c,

102d to access the PSTN 108, the Internet 110, and/or the other networks 112. The PSTN 108 may include circuit-switched telephone networks that provide plain old telephone service (POTS). The Internet 110 may include a global system of interconnected computer networks and devices that use common communication protocols, such as the transmission control protocol (TCP), user datagram protocol (UDP) and/or the internet protocol (IP) in the TCP/IP internet protocol suite. The networks 1 12 may include wired and/or wireless communications networks owned and/or operated by other service providers. For example, the networks 112 may include another CN connected to one or more RANs, which may employ the same RAT as the RAN 104/1 13 or a different RAT.

[0041] 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 1 14a, which may employ a cellular-based radio technology, and with the base station 1 14b, which may employ an IEEE 802 radio technology.

[0042] FIG. 1 B is a system diagram illustrating an example WTRU 102. As shown in FIG.

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

[0043] 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 Array (FPGA) 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 118 may be coupled to the transceiver 120, which may be coupled to the transmit/receive element 122. While FIG. 1 B depicts the processor 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.

[0044] The transmit/receive element 122 may be configured to transmit signals to, or receive signals from, a base station (e.g., the base station 114a) over a respective 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.

[0045] 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 respective air interfaces 116.

[0046] The transceiver 120 may be configured to modulate the signals that are to be transmitted by the transmit/receive element 122 and to demodulate the signals that are received by the transmit/receive element 122. As noted above, the WTRU 102 may have multi-mode capabilities. Thus, the transceiver 120 may include multiple transceivers for enabling the WTRU 102 to communicate via multiple RATs, such as NR and IEEE 802.11 , for example.

[0047] The processor 118 of the WTRU 102 may be coupled to, and may receive user input data from, the speaker/microphone 124, the keypad 126, and/or the display/touchpad 128 (e.g., a liquid crystal display (LCD) display unit or organic light-emitting diode (OLED) display unit). The processor 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).

[0048] The processor 118 may receive power from the power source 134, and may be configured to distribute and/or control the power to the other components in the WTRU 102. The power source 134 may be any suitable device for powering the WTRU 102. For example, the power source 134 may include one or more dry cell batteries (e.g., nickel-cadmium (NiCd), nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion), etc.), solar cells, fuel cells, and the like.

[0049] The processor 118 may also be coupled to the GPS chipset 136, which may be configured to provide location information (e.g., longitude and latitude) regarding the current location of the WTRU 102. In addition to, or in lieu of, the information from the GPS chipset 136, the WTRU 102 may receive location information over a respective air interface 116 from a base station (e.g., base stations 114a, 114b) and/or determine its location based on the timing of the signals being received from two or more nearby base stations. It will be appreciated that the WTRU 102 may acquire location information by way of any suitable location-determination method while remaining consistent with an embodiment.

[0050] The processor 118 may further be coupled to other peripherals 138, which may include one or more software and/or hardware modules that provide additional features, functionality and/or wired or wireless connectivity. For example, the peripherals 138 may include an accelerometer, an e-compass, a satellite transceiver, a digital camera (for photographs and/or video), a universal serial bus (USB) port, a vibration device, a television transceiver, a hands free headset, a Bluetooth® module, a frequency modulated (FM) radio unit, a digital music player, a media player, a video game player module, an Internet browser, a Virtual Reality and/or Augmented Reality (VR/AR) device, an activity tracker, and the like. The peripherals 138 may include one or more sensors, the sensors may be one or more of a gyroscope, an accelerometer, a hall effect sensor, a magnetometer, an orientation sensor, a proximity sensor, a temperature sensor, a time sensor; a geolocation sensor; an altimeter, a light sensor, a touch sensor, a magnetometer, a barometer, a gesture sensor, a biometric sensor, and/or a humidity sensor.

[0051] 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 139 to reduce and or substantially eliminate self-interference via either hardware (e.g., a choke) or signal processing via a processor (e.g., a separate processor (not shown) or via processor 118). In an embodiment, the WTRU 102 may include a half-duplex radio for which transmission and reception of some or all of the signals (e.g., associated with particular subframes for either the UL (e.g., for transmission) or the downlink (e.g., for reception)).

[0052] FIG. 1C is a system diagram illustrating the RAN 104 and the CN 106 according to an embodiment. As noted above, the RAN 104 may employ an E-UTRA radio technology to communicate with the WTRUs 102a, 102b, 102c over respective air interfaces 116. The RAN 104 may also be in communication with the CN 106.

[0053] 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 respective air interfaces 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.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] The SG W 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.

[0058] 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.

[0059] The CN 106 may facilitate communications with other networks. For example, the

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

[0060] Although the WTRU is described in FIGS. 1A-1 D as a wireless terminal, it is contemplated that in certain representative embodiments that such a terminal may use (e.g., temporarily or permanently) wired communication interfaces with the communication network.

[0061] In representative embodiments, the other network 112 may be a WLAN.

[0062] 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 in to and/or out of the BSS. Traffic to STAs that originates from outside the BSS may arrive through the AP and may be delivered to the STAs. Traffic originating from STAs to destinations outside the BSS may be sent to the AP to be delivered to respective destinations. Traffic between STAs within the BSS may be sent through the AP, for example, where the source STA may send traffic to the AP and the AP may deliver the traffic to the destination STA. The traffic between STAs within a BSS may be considered and/or referred to as peer-to-peer traffic. The peer- to-peer traffic may be sent between (e.g., directly between) the source and destination STAs with a direct link setup (DLS). In certain representative embodiments, the DLS may use an 802.1 1e DLS or an 802.11z tunneled DLS (TDLS). A WLAN using an Independent BSS (IBSS) mode may not have an AP, and the ST As (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.

[0063] When using the 802.1 1 ac infrastructure mode of operation or a similar mode of operation, 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.

[0064] 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.

[0065] Very High Throughput (VHT) STAs may support 20MHz, 40 MHz, 80 MHz, and/or

160 MHz wide channels. The 40 MHz, and/or 80 MHz, channels may be formed by combining contiguous 20 MHz channels. A 160 MHz channel may be formed by combining 8 contiguous 20 MHz channels, or by combining two non-contiguous 80 MHz channels, which may be referred to as an 80+80 configuration. For the 80+80 configuration, the data, after channel encoding, may be passed through a segment parser that may divide the data into two streams. Inverse Fast Fourier Transform (IFFT) processing, and time domain processing, may be done on each stream separately. The streams may be mapped on to the two 80 MHz channels, and the data may be transmitted by a transmitting STA. At the receiver of the receiving STA, the above described operation for the 80+80 configuration may be reversed, and the combined data may be sent to the Medium Access Control (MAC).

[0066] Sub 1 GHz modes of operation are supported by 802.11 af and 802.11 ah. The channel operating bandwidths, and carriers, are reduced in 802.11 af and 802.11 ah relative to those used in 802.1 1 η, and 802.11 ac. 802.11 af supports 5 MHz, 10 MHz and 20 MHz bandwidths in the TV White Space (TVWS) spectrum, and 802.1 1ah 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, 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).

[0067] WLAN systems, which may support multiple channels, and channel bandwidths, such as 802.1 1 η, 802.11 ac, 802.1 1 af, and 802.1 1ah, include a channel which may be designated as the primary channel. The primary channel may have a bandwidth equal to the largest common operating bandwidth supported by all STAs in the BSS. The bandwidth of the primary channel may be set and/or limited by a STA, from among all STAs in operating in a BSS, which supports the smallest bandwidth operating mode. In the example of 802.11 ah, the primary channel may be 1 MHz wide for STAs (e.g., MTC type devices) that support (e.g., only support) a 1 MHz mode, even if the AP, and other STAs in the BSS support 2 MHz, 4 MHz, 8 MHz, 16 MHz, and/or other channel bandwidth operating modes. Carrier sensing and/or Network Allocation Vector (NAV) settings may depend on the status of the primary channel. If the primary channel is busy, for example, due to a STA (which supports only a 1 MHz operating mode), transmitting to the AP, the entire available frequency bands may be considered busy even though a majority of the frequency bands remains idle and may be available.

[0068] In the United States, the available frequency bands, which may be used by

802.1 1ah, 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.

[0069] FIG. 1 D is a system diagram illustrating the RAN 113 and the CN 115 according to an embodiment. As noted above, the RAN 1 13 may employ an NR radio technology to communicate with the WTRUs 102a, 102b, 102c over respective air interfaces 116. The RAN 113 may also be in communication with the CN 115.

[0070] The RAN 113 may include gNBs 180a, 180b, 180c, though it will be appreciated that the RAN 113 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 respective air interfaces 116. In one embodiment, the gNBs 180a, 180b, 180c may implement MIMO technology. For example, gNBs 180a, 108b may utilize beamforming to transmit signals to and/or receive signals from the gNBs 180a, 180b, 180c. Thus, the gNB 180a, for example, may use multiple antennas to transmit wireless signals to, and/or receive wireless signals from, the WTRU 102a. In an embodiment, the gNBs 180a, 180b, 180c may implement carrier aggregation technology. For example, the gNB 180a may transmit multiple component carriers to the WTRU 102a (not shown). A subset of these component carriers may be on unlicensed spectrum while the remaining component carriers may be on licensed spectrum. In an embodiment, the gNBs 180a, 180b, 180c may implement Coordinated Multi-Point (CoMP) technology. For example, WTRU 102a may receive coordinated transmissions from gNB 180a and gNB 180b (and/or gNB 180c).

[0071] 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).

[0072] The gNBs 180a, 180b, 180c may be configured to communicate with the WTRUs

102a, 102b, 102c in a standalone configuration and/or a non-standalone configuration. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c without also accessing other RANs (e.g., such as eNode-Bs 160a, 160b, 160c). In the standalone configuration, WTRUs 102a, 102b, 102c may utilize one or more of gNBs 180a, 180b, 180c as a mobility anchor point. In the standalone configuration, WTRUs 102a, 102b, 102c may communicate with gNBs 180a, 180b, 180c using signals in an unlicensed band. In a non-standalone configuration WTRUs 102a, 102b, 102c may communicate with/connect to gNBs 180a, 180b, 180c while also communicating with/connecting to another RAN such as eNode-Bs 160a, 160b, 160c. For example, WTRUs 102a, 102b, 102c may implement dual connectivity 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 WTRUc 102a, 102b, 102c.

[0073] 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.

[0074] The CN 1 15 shown in FIG. 1 D may include at least one AMF 182a, 182b, at least one UPF 184a, 184b, at least one Session Management Function (SMF) 183a, 183b, and possibly a Data Network (DN) 185a, 185b. While 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.

[0075] 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 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 182a, 182b may provide a control plane function for switching between the RAN 113 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.

[0076] 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 115 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.

[0077] 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 110, to facilitate communications between the WTRUs 102a, 102b, 102c and IP-enabled devices. The UPF 184, 184b may perform other functions, such as routing and forwarding packets, enforcing user plane policies, supporting multi- homed PDU sessions, handling user plane QoS, buffering downlink packets, providing mobility anchoring, and the like.

[0078] The CN 1 15 may facilitate communications with other networks. For example, the

CN 1 15 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.

[0079] In view of FIGS. 1A-1 D, and the corresponding description of Figures 1A-1 D, one or more, or all, of the functions described herein with regard to one or more of: WTRU 102a-d, Base Station 1 14a-b, eNode-B 160a-c, MME 162, SGW 164, PGW 166, gNB 180a-c, AMF 182a-ab, UPF 184a-b, S F 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.

[0080] 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.

[0081] 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.

[0082] As used herein, Aperiodic Auto Correlation (APAC) is defined as follows. Let p for be the aperiodic autocorrelation of a complex sequence a =

and is explicitly given by:

where

and

where is the conjugate of its argument and

[0083] As used herein, Periodic Auto Correlation (PAC) is defined as follows.

Let r _a (k) be the periodic autocorrelation of the sequence

explicitly given by:

where (i) _N is the modulo of i.

[0084] As used herein, Golay Complementary Sequences are defined as follows.

The pair of (a, b) is called a Golay complementary pair (or sequences) if

[0085] In telecommunications, Golay complementary pairs and sequences have been proposed for PAPR mitigation, estimation of in-phase (I) and quadrature (Q) (IQ) imbalance parameters, and channel estimation due to its unique features.

[0086] As used herein, Golay complementary sequence construction for larger lengths

(Budisin's method) are defined as follows.The length Golay complementary pairs can be

constructed by the following recursive procedure:

where is the Kronecker's delta, and w _m is the mth element of rotation vector is the mth element of the delay vector d -

and the permutation of

[0087] In the IEEE 802.11 ad standard, the pairs of Golay complementary sequences (i.e.,

Golay complementary pairs) are generated based on the aforementioned method, and three pairs are considered: The parameters of these pairs

are listed as follows:

where flip{-} reverses the order of its argument. It is noted that, in 802.11 ad, the Golay sequences are not only used in a short training field (STF) and a channel estimation field (CEF), they are also used in single carrier (SC) PHY (Ga64) and low power SC PHY (Ga64 and G8) for guard interval (Gl), as well as in beamforming training (TRN) field.

[0088] Golay complementary sequences with the alphabet of are known to exist for

all lengths for any non-negative integers n, m and k.

[0089] A time-domain power signal may be expressed as a function of APAC. For example, one can represent a sequence with a polynomial as:

where the sequence

[0090] Therefore, is equivalent to OFDM signal in time (i.e., the Fourier

transform of a), and if the instantaneous power can be calculated as

If the instantaneous power is known, the PAPR can be

measured. In addition, is related to APAC of the sequence. It can be

expressed as follows:

constant) must hold true. This means the time domain signal has to be unimodal in every point in time. By using the equation above, the PAPR of any sequence is bounded as:

where £[·] is the integration operation for t from 0 to 2π.

[0092] It is noted that PAPR can also be equivalently measured by two quantities, integrated sidelobe level (ISL) and merit factor (MF) of a sequence and are defined as follows:

[0093] In one embodiment, an ultra-low PAPR (ULP) sequence is defined as the family of unimodular sequences such that when the elements of the sequence are mapped to the subcarriers of an OFDM symbols in certain ways, the PAPR of the corresponding time-domain analog signal (or sufficiently oversampled IDFT output samples) is less than 3 dB (or 2 in linear scale), i.e.,

[0094] For example, it has been shown that the PAPR of a sequence of a complementary pair of sequences is always less than 3 dB. Since Golay pairs a and b satisfy p _a (k) + p _b (k) = 0, k≠ 0, the following holds true:

[0095] As a result, the PAPR of a Golay sequence is bounded as:

[0096] Hence, a Golay sequence is an ULP sequence.

[0097] Standardized modifications to both the IEEE 802.1 1 physical (PHY) layer and the

IEEE 802.11 medium access control (MAC) layer are expected that enable at least one mode of operation capable of supporting a maximum throughput of at least 20 gigabits per second (measured at the MAC data service access point), while maintaining or improving the power efficiency per station. These modifications may also define operations for license-exempt bands above 45 GHz while ensuring backward compatibility and coexistence with legacy directional multi- gigabit stations (e.g., defined by IEEE 802.1 1 ad) operating in the same band. Although, a much higher maximum throughput than that currently offered by 802.11 ad is a goal, some proposals may include mobility and outdoor support. Since the IEEE 802.1 l ay amendment will operate in the same band as legacy standards, it is required that the new technology will ensure backward compatibility and coexistence with legacy technologies in the same band.

[0098] To reach the maximum throughput requirement for the mmW band, multiple technologies have been proposed. They include single user (SU)-MIMO (i.e., multiple stream), channel bonding, higher order modulation, and non-uniform modulation. In order to support more features, wider usage scenarios (e.g., outdoor and mobility) and overall system capacity, other technologies may be included, for example MU-MIMO and enhanced relay.

[0099] FIG. 2 shows an example of an enhanced directional multi-gigabit (EDMG) PPDU format 200 for an IEEE 802.1 l ay packet. The EDMG PPDU 200 may include a legacy STF (L-STF) 202, a legacy CEF (L-CEF) 204, a legacy header (L-Header) 206, an EDMG Header-A field 208, an EDMG-STF 210, an EDMG-CEF 212, an EDMG Header-B field 214, a data field 216, and a TRN field 218. Fields 202-208 may be modulated using legacy (i.e. non EDMG) modulation techniques. Fields 210-218 may be modulated using EDMG modulation techniques. In 802.11 ay, the PPDUs may be transmitted using either single carrier (SC) mode or OFDM mode. To enable OFDM transmission, in the EDMG PPDU format 200, the EDMG-STF 210, the EDMG-CEF 212, the EDMG Header-B field 214, the data field 216, and the TRN field 218 may be modulated using OFDM.

[0100] There are several proposals for the EDMG OFDM PHY which use the pair of sequences SeqiSTSIeft.N and SeqiSTSright.N, where iSTS = 1 , 2, 8, of length N to generate the EDMG-CEF field in the frequency domain for a single channel. Three direct current (DC) tones are also included between the left and the right sequences. Although it has been reported that these sequences have less than 3.8 dB PAPR for a small Discrete Fourier transform (DFT) size, the time domain PAPR of these sequences (i.e., for large DFT sizes) can be as large as 5 dB PAPR.

[0101] In one embodiment, ULP sequences with fixed zero elements and flexible symbol density by using Golay sequences may be used. As noted above, a Golay sequence is a ULP sequence. However, the length of a Golay sequence is restricted when the alphabet of the sequence is limited. Thus, the following methods may be used to generate new ULP sequences with different symbol density, defined as a number of non-zero elements/total number of elements of the sequence, tor a CEF and a TRN field of IEEE 802.11 ay PPDUs. [0102] In one embodiment, a method of upsampling may be used to generate new ULP sequences with different symbol density. FIG. 3 illustrates a block diagram of a transmitter 300 for generating ULP sequences using an upsampling operation. Ga is a Golay sequence of length of L _b and T _u 302 is an operator that upsamples the input vector where u is the upsampling factor. After removing the last u - 1 zeros due to the upsampling 304, the result vector of length of L = uL _b - u + 1 is still a ULP sequence. Then, a rotator 306 will rotate the resulting vector with a complex scaler. A mapper 308 will then map the rotated vestor to the subcarriers of Inverse Discrete Fourier Transform (IDFT) 310 to generate OFDM symbols (e.g., in CEF and/or TRN fields). A cyclic prefix is added 312, and a radio frequency upconverter 314 brings the signal to the RF band for transmission. At a receiver side, the channel estimation or tracking may be performed based on the non-zero received symbols.

[0103] In another embodiment, a method utilizing staggering and adding/subtracting (SAS) may be used to generate new ULP sequences with different symbol density. FIG. 4 illustrates a block diagram 400 of a method for generating ULP sequences using an SAS operation. For example, the sequences of a complementary Golay pair may be shifted and added (or subtracted) together 430, mapped to the subcarriers 440 and N-point inverse DFT of the mapped sequence may be calculated 450 and cyclic prefix may be prepended 460 to construct an OFDM symbol (e.g., in CEF and/or TRN fields. This newly constructed sequence via SAS is still a Golay sequence if the sequence is one of the sequences of Golay complementary pairs (GCP). The constructed OFDM symbol may transmitted an RF chain 470.

[0104] Referring to FIG. 4, G _a and G _b are a pair of Golay sequences and o is an overlapping factor. While negative o indicates that the Golay sequences are separated with o zeros in between G _a and G _b (as shown by 410 in FIG. 4); positive o indicates that the Golay sequences are overlapped (as shown by 420 in FIG. 4). This operation may be used to achieve frequency diversity in certain scenarios, e.g., such uplink control channels, while controlling the PAPR of the transmitted signal.

[0105] In another embodiment, a method utilizing both SAS and upsampling may be used to generate new ULP sequences with different symbol density. FIG. 5 illustrates generating ULP sequences using upsampling and staggering operations. In one case, a ULP sequence may be obtained by adding G _a and G _b shifted by s, where s≤ u - 1 as shown by 510. Here, again, u is the upsampling factor. In another case, a ULP sequence may be obtained by subtracting G _a and G _b shifted by s, where s≤ u - 1 as shown by 520. [0106] FIG. 6 illustrates a method of OFDM generation with an ULP sequence according to one embodiment. In particular, in FIG. 6, a complete ULP sequence is generated by using the upsampling and SAS operations, as described above, with u=2.

[0107] Referring to FIG. 6, first, Golay complementary pairs (GCP), denoted by Ga and

Gb, of lengths of are generated 605. Ga and Gb are upsampled 610 by the

factor of u and the last u - 1 elements from the upsampled vectors are removed 615. These vectors are denoted as Gau and Gbu. Next, vector Gbus is generated by shifting Gbu by s 625. Next, vector Gau and Gbus are multiplied with arbitrary complex scalar e ^je 620. The complex scalars for Gau and Gbus may be different. Then, Ga' is generated according to Gau + Gbus 630 and Gb' is generated according to Gau - Gbus 635. Next, SAS is applied by using the overlapping factor of o to Ga' and Gb', as described above, 640. The resulting vector is denoted as Gc. The ULP sequence is generated by padding p zeros to the edge of the vector Gc 645. The ULP sequence is then mapped to subcarriers via a mapping operation 650, and the (inverse) DFT of the mapped ULP sequence is calculated 655. Lastly, a cyclic prefix is appended to the signal 660 and the signal is transmitted 665. It will be appreciated by those skilled in the art that the operations described above are not limited in order, and changes in the order will be apparent.

[0108] By using the ULP sequence and the parameters defined above, CEF and TRN waveforms may be generated in different ways. For example, if a constraint is 3 zero DC tones, one may generate the base ULP sequences for TRN or CEF as given in Table 1 below for the following stre

[0109] The above sequences may be used for signals transmitted in, for example,

2.16GHz, 4.32GHz, 6.48GHz and 8.64GHz channel bandwidths, respectively. The symbol density is measured by the ratio of number of non-zero elements and sequence length.

[01 10] If the constraint is 1 zero DC tones, one may generate the ULP sequences for TRN or CEF as given in Table 2 below.

[0111] Furthermore, Table 3 provides ULP parameters with o > 0 for IEEE 802.11 ay CEF and/or TRN fields.

[01 12] In one embodiment, M zeros may be padded to sequences of a complementary pair and then recursively updated by using Budisin's method. For example, where the sequence length is N, after the padding, the sequence length is N + M. Then, by using a recursive method, a ULP sequence can be genereated of L = 2" x (N + M), where n is a positive integer. In this method, there will be M zeros after N non-zero symbols in frequency.

[01 13] In another embodiment, the zero symbols in a ULP sequence may be replaced with some non-zeros values to minimize the PAPR and to construct a sequence without zeroes.

[01 14] In another embodiment, ULP sequences may be used that have a flexible subcarrier mapping. For example, CEF and/or TRN fields may utilize the ULP sequences generated through the following method:

Set to an initial sequence;

Set∈ to a positive value;

Set n = 0;

[0115] In this method, e is a value for the convergence, M is a mapping (permutation) matrix, F _N is the DFT matrix of size N, b = constant{a} is an operator which modifies the elements of a as bj = aj/|aj | and b = quantize{a, S) is where S is

the alphabet, e.g., the elements of the chosen modulation constellation. For example, if the constellation is 4-phase-shift keying (PSK) (4PSK), S may be S = {+l, -l, +j, -j}; if the constellation is 64PSK, S may be S = {e ⁱ² ™/ ⁶⁴ |n 6 [0,1 63]}.

[0116] The mapping may also be constructed based on desired symbol density and DC tones in an OFDM symbol. For example, 3 DC tones may be desired for the following numerology for IEEE 802.1 l ay CEF fields:

[0117] Here, Neb indicates the number of bonded channels of 2.16 GHz. The above sequences may be used for signals transmitted in 2.16GHz, 4.32GHz, 6.48GHz and 8.64GHz channel bandwidths, respectively.

[0118] FIG. 7 shows a block diagram of a method 700 of ULP sequence generation using iterative DFT loops. First, an initial sequence is generated 705. After the elements of the initial sequence are modified with the operator of constant 710, they are mapped to subcarriers 715. In this example, there are three DC tones (shown as zeros in the mapping 715). It is also noted that this is merely an example, and one may choose any number of tones. For example, for STF design, one may choose an interleaving mapping to generate replicas in the time domain. After the mapping, the sequence is converted to the time domain via an inverse DFT operation 720. Then, the operation of constant{-} is applied to the time domain signal 725 and converted back to the frequency domain via a DFT operation 730. The operation of constant{-} may change the amplitude of the elements of the input vector to be 1 and assign it to an output vector. After the de- mapping operation 735, which includes a concatenation of Sright and Sleft, the initial sequence is replaced with the newly generated sequence. After this loop runs for a sufficient/desired number of iterations, the output of the operation of constant 740, as in FIG. 7, may be considered as in the family of ULP sequences (PAPR evaluations may need to done at this step).

[0119] Since the element of the vector after the operation of constant^} is on the unit circle arbitrary, one may replace the elements with the closest element of a constellation diagram (e.g., 64PSK). Typically, a higher density represents the original ULP sequences better. Table below, ULP sequences are generated with the method described above in reference to FIG. 7 by using 64PSK modulation. As shown in Tables 4-7 below, the sequences yield a PAPR of less than 2.4 dB, which is significantly lower than that of the existing (conventional) EDMG-CEF OFDM sequences, as shown in FIGS. 8-11. In particular, FIGS. 8-11 , corresponding to Tables 4-7, respectively, illustrate PAPR results corresponding to the ULP sequences generated via the method illustrated in FIG. 7 and conventional EDMG-EDMG-CEF OFDM sequences.

[0120] It is worth noting that the ULP sequences shown in Tables 4-7 have identical PAPR results in a phase rotation and/or a circular time shift for an OFDM symbol (or frequency domain modulation with complex exponentials). [0121] In another embodiment, spatial mapping with a ULP sequence includes sequence generation for different streams by using the ULP sequences. For example, in one method, a circular shift in time for an OFDM symbol in the time domain may be used to decrease the correlation between the spatial streams. To this end, the mapped sequences in the frequency domain may be multiplied with where k = [1: N] and ξ is the shifting factor. The

corresponding phase rotations for each element of the Sleft and Sright can be calculated after the mapped sequences are multiplied by In order to not change the symbol alphabet, the ξ

value may be specifically set to selected values. For example, if the elements of Sleft and Sright are in S = {1, -1, j, j}, there are only 4 values of ξ that may be used, i.e., ξ = {0, 0.25,0.5,0.75}. If 64PSK modulation is selected , there are 64 different values of ξ that can be used without affecting the alphabet.

[0122] In the case of there are only 4 streams without affecting the

symbol. In this case, to generate more low correlated special sequences, one or more of the following may be performed: 1 ) change the order of the Golay sequences (e.g., Ga' and Gb' may be switched); 2) change the order of the summation and subtraction operations; 3) reversing the order of the elements of sequences (flipping); 4) conjugate the sequences; and/or 5) use different phase Θ in the method shown in FIG. 6, for additional sequences.

[0123] Thus, ULP sequences may be generated having a set limited alphabet while having a lower spatial correlation.

[0124] In one embodiment, signaling may be performed with Golay sequences. In particular, a combination of Golay sequences or ULP sequences may be mapped to the subcarriers to achieve a low PAPR signal. FIG. 12 illustrates different applications of sequence-based messaging using Golay sequences. Here, as long as the mapped symbols construct a Golay sequence (or a ULP sequence) in the frequency domain, the PAPR would be limited to 3 dB or less. Thus, these sequences may be used to modulate some messages, e.g., ACK, NACK, or SR with low PAPR such that the PAPR of the sequence-based messaging channels is controlled. Such messaging may be used with frequency diversity. Referring to FIG. 12, an apparatus 1200 for transmitting a data symbol belonging to a constellation may be multiplied with the Golay sequences. The signal produced may be fed to an IDFT 1202, a cyclic prefix may be added 1204, and the signal may be transmitted 1206.

[0125] Still referring to FIG. 12, Golay complementary pairs Ga and Gb may be used to indicate different messages. In the apparatus 1220, Ga may be, or may represent, an ACK symbol, while Gb may be, or may represent, a NACK symbol, and the combination of Ga+Gb may be, or may represent, a scheduling request (SR). A processor (not shown) selects the symbol to be sent, and the selected signal may be fed to an IDFT 1222, a cyclic prefix may be added 1224, and the signal may be transmitted 1226. In the apparatus 1220, Ga and Gb may be designed from a real alphabet, e.g. {-1 ,1} and a phase rotation may be applied when a SR signal is selected. A Golay sequence in frequency may be used to generate sounding reference symbols (SRS) for OFDM.

[0126] In another example, still referring to FIG. 12, the Golay complementary pairs Ga and Gb may be mapped to different frequency resources, e.g., different resource blocks (RBs), to achieve frequency diversity. In this case, the order of Ga and Gb (e.g., Ga, Gb or Gb, Ga) in frequency may indicate an ACK or a NACK. Apparatus 1240 includes a processor (not shown) that selects a desired signal (ACK or NACK). The order of the Ga and Gb in frequency domain is thus selected based on the desired signal. As shown in apparatus 1240, Ga first followed by Gb in frequency domain indicates an ACK, and Gb first followed by Ga in frequency domain indicates a NACK, in this example, although the opposite is obviously possible as well. Thus, the order of the sequences in frequency defines the information being conveyed (ie. ACK or NACK). The selected signal may be fed to an IDFT 1242, a cyclic prefix may be added 1244, and the signal may be transmitted 1246.

[0127] In another example, still referring to FIG. 12, Ga and Gb may be upsampled and mapped to interleaved subcarriers (indicate in FIG. 12 by the shift). Since a Golay sequence is a ULP sequence, the PAPR is limited to 3dB. The order of the upsampled Ga and Gb (e.g., Ga, Gb or Gb, Ga) may indicate the ACK+SR or NACK+SR. Apparatus 1260 includes a processor (not shown) that selects the desired signal for transmission (ACK+SR or NACK+SR) and the corresponding Golay sequences. The selected signal may be fed to an IDFT 1262, a cyclic prefix may be added 1264, and the signal may be transmitted 1266

[0128] As shown in FIG. 13, the property of Golay sequences may be beneficial for short

PUCCH transmission. For example, in one scenario, one of the pairs may be employed with certain cyclic shifts to achieve ACK and NACK sequences. In another scenario, ACK and NACK may be generated through the complementary pairs, e.g., a may represent the ACK and b may represent the NACK. Since the combination of a ± b is also limited by 3 dB PAPR, the combination may also be used to indicate other information, e.g., SR. In another scenario the pairs may be mapped to different frequency domain resources. Since the PAPR of the time domain signal is also limited by 3dB due to the properties of complementary sequences, signaling ACK and NACK by alternating the locations of a and b in frequency domain is possible. The method may achieve better performance in frequency selective channel. Time domain cyclic shift may be also be applied. In another embodiment, different pairs may be assigned to different users on the same resources. [0129] FIG. 13 shows three apparatuses that use different options for low PAPR (<3dB) for use in short physical uplink control channel (PUCCH) transmission with 1-2 bits by using Golay complementary pairs. In particular, apparatus 1300 uses cyclic shifts of a Golay sequence for ACK and NACK. Apparatus 1320 uses a Golay pair and their various combinations for ACK, NACK, and SR. Apparatus 1340 uses alternate allocation of a Golay pair for ACK and NACK.

[0130] Apparatus 1300 includes a processor (not shown) that determines whether an ACK or a NACK is desired for transmission. Golay sequence a is cyclic shifted in time depending on whether ACK or NACK is desired for transmission 1302. The resulting signal is converted to the frequency domain via IDFT 1304. A cyclic prefix is added 1306 and the resulting signal is transmitted 1308.

[0131] Apparatus 1320 includes a processor (not shown) that determines whether an ACK,

NACK, or SR is desired for transmission. Golay sequences a and b are cyclic shifted in time depending on whether an ACK, NACK, or SR is desired for transmission 1322. In apparatus 1320, Golay sequence a is used for an ACK, and Golay sequence b is used for a NACK. A combination of sequences a and b is used for an SR. This is exemplary, however, and the opposite selection is obviously possible. The resulting signal is converted to the frequency domain via IDFT 1324. A cyclic prefix is added 1326 and the resulting signal is transmitted 1328.

[0132] Apparatus 1340 includes a processor (not shown) that determines whether an Ack or a NACK is desired for transmission. A Golay pair of sequences a and b are used to transmit both the ACK or the NACK. The order of the pair determines whether the signal is an ACK or a NACK. Once the processor has selected the desired signal for transmission (ACK or NACK, and corresponding ordered pair of sequences), the sequences are cyclic shifted in time 1342. The resulting signal is converted to the frequency domain via IDFT 1344. A cyclic prefix is added 1346 and the resulting signal is transmitted 1348.

[0133] Golay sequences are available with a restricted alphabet such as QPSK. For example, there are 36,864 Golay sequences of length of 12 with the alphabet of QPSK with a computer sequence. The length of 24 and 48 can be generated recursively by using length of 12 sequences if necessary. One may use these sequences for short PUCCH transmission along with the aforementioned methods.

[0134] In another embodiment, a unimodular sequence which leads to a low PAPR may be generated with the following algorithm for short PUCCH transmission. Referring to FIG. 14, an apparatus 1400 is disclosed for generating a ULP sequence for short PUCCH transmission.

A processor (not shown) selects an initial sequence a of length L 1402, and iteration lndex=0 and numberOflterations = M are set. Sequence a is mapped to a selected set of subcarriers by a mapping unit 1404. The inverse N-point DFT of the mapped sequence a is calculated to generate sequence b 1406. The ith elements of sequence b, bj are scaled, such that |bj | = k, where k is a constant 1408. The N-point DFT of the scaled sequence is calculated to generate sequence c 1410. Sequence c (i.e., get only L elements of sequence c) is punctured to generate sequence d 1412. The kth elements of sequence d are scaled, i.e., d _k , such that |d _k | = m, where m is a constant 1414. A processor (not shown) determines whether iterationlndex < M. If it is, the process iterates and iterationlndex := iterationlndex + 1. If it is not, d/d _x is set as the final sequence 1416.

[0135] After the final ULP sequence is generated, the elements of the sequence may be quantized based on a PSK constellation. Note that this method generates one sequence at a time. Multiple sequences may be generated and discarded or accepted by evaluating at the correlation of the sequences (and including their cyclic shifts). For example, if the PSK constellation is 16PSK, the sequence for short PUCCH for oneRB, two contiguous RBs, and two discontinuous RBs may be obtained as shown in Table 8.

[0136] In the case of dynamic RB allocation, one method is to use a fixed separation between the RBs for Short PUCCH in order not to increase PAPR (for example, {1 ,51}, {2,52}, and so on for the allocation of sequences).

[0137] The superiority of the sequences is illustrated in Table 9, below. While ULP achieves the best PAPR results (2 dB), Golay sequences offer frequency diversity without increasing the PAPR more than 3 dB. ZC sequences generally do not perform well in terms of PAPR.

[0138] As can be seen from FIG. 15, which shows the PAPR performance for the various short PUCCH methods, the peak sample power with ZC sequences is 4 dB higher than the mean power with 1 % probability. Especially, if frequency diversity is introduced by using two discontinuous RBs, PAPR reaches 5 dB at 1 % probability. On the other hand, computer generated sequences (i.e., ULPs) achieve significantly improved PAPR performance. With ULPs, the peak sample power is only 2 dBhigher than the mean power at 1 % probability for both the case with only one RB and the case with 2 contiguous RBs . The peak sample power is only 3 dB higher than the mean power at 1% probability for the case with 2 non-contiguous RBs [0139] Complementary Golay sequences are superior to ZC sequences and yield 3 dB

PAPR maximum. It is worth noting that Golay sequences achieve 3 dB in all three RB allocations. In particular, they do not increase the PAPR when the sequences in a complementary pair are mapped to two discontinuous RBs. This may not be easily achieved by the ULPs.

[0140] Referring to FIG. 16, a method 1600 for use in a wireless transmit/unit is shown. In the method 1600, a processor of the WTRU generates a pair of complementary Golay sequences 1610, as described herein. The processor may use any of the methods described in the various embodiments herein to Generate the pair of complementary Golay sequences. Moreover, the pair of complementary Golay sequences have the property that a sum of a direct autocorrelation function of each sequence is zero when the length of the sequences D and D is non-zero. The processor of the WTRU encodes data intended for a gNode-B with at least one sequence of the pair of Golay sequences 1620, as described in the various embodiments disclosed herein. The data intended for transmission may be an ACK, NACK, SR, or some combination of these. The encoded data is then processed via an IDFT 1630. The resulting OFDM signal is then transmitted to the gNode-B 1640.

[0141 ] Although features and elements are described above in particular combinations, one of ordinary skill in the art will appreciate that each feature or element can be used alone or in any combination with the other features and elements. In addition, the methods described herein may be implemented in a computer program, software, or firmware incorporated in a computer- readable medium for execution by a computer or processor. Examples of computer-readable media include electronic signals (transmitted over wired or wireless connections) and computer-readable storage media. Examples of computer-readable storage media include, but are not limited to, a read only memory (ROM), a random access memory (RAM), a register, cache memory, semiconductor memory devices, magnetic media such as internal hard disks and removable disks, magneto-optical media, and optical media such as CD-ROM disks, and digital versatile disks (DVDs). A processor in association with software may be used to implement a radio frequency transceiver for use in a WTRU, UE, terminal, base station, RNC, or any host computer.