WO2018064582A1

WO2018064582A1 - Grant-free uplink non-orthogonal multiple access transmissions

Info

Publication number: WO2018064582A1
Application number: PCT/US2017/054509
Authority: WO
Inventors: Debdeep CHATTERJEE; Gang Xiong; Seunghee Han; Sergey Sosnin; Hwan-Joon Kwon
Original assignee: Intel IP Corporation
Priority date: 2016-09-30
Filing date: 2017-09-29
Publication date: 2018-04-05

Abstract

Grant-free UL transmissions based on non-orthogonal multiple access (NOMA) may be considered as applicable various use cases including massive connectivity for machine type communication (MTC) and low overhead UL transmission schemes that minimize device power consumption for transmission of small data packets. Described herein are methods, apparatus, and mechanisms are described for MA resource configuration and MA resource selection in the context of grant-free UL transmission. Also described herein are methods and apparatus that incorporate retransmission and HARQ schemes for grant-free UL NOMA transmissions.

Description

Priority Claim

[0001] This application claims priority to United States Provisional Patent Application Serial No. 62/402,522, filed September 30, 2016, and to United States Provisional Patent Application Serial No. 62/402,530, filed September 30, 2016, which are incorporated herein by reference in its entirety.

Technical Field

[0002] Embodiments described herein relate generally to wireless networks and communications systems. Some embodiments relate to cellular communication networks including 3 GPP (Third Generation Partnership Project) networks, 3GPP LTE (Long Term Evolution) networks, 3 GPP LTE-A (LTE Advanced), and 3 GPP fifth generation (5G) or new radio (NR) networks, although the scope of the embodiments is not limited in this respect.

Background

[0003] Mobile wireless communications systems have evolved from early voice- only systems to today's highly sophisticated integrated communication platforms in which fourth generation (4G) LTE networks provide data for massive mobile services.

Next generation (a.k.a, fifth generation (5G) or new radio (NR)) technology is being developed to meet the increased future demands brought about by use cases such as enhanced mobile broadband, ultra-reliable and low-latency communications, and machine-to-machine communications for enabling the Internet of Things (ϊοΤ). 5G technology builds on a combination of existing 4G and new technologies to meet these demands.

[0004] Non-orthogonal multiple access (NOMA) is considered to be an important enabling technology for 5G wireless networks to meet the demands of low latency, high reliability, massive connectivity, and high throughput. The basic idea of NOMA is to serve multiple users in the same bandwidth resource, such as time slots, subcarriers, or spreading codes. The NOMA concept forms a general framework where different multiple access schemes may be employed for distinguishing one user from another. NOMA has the potential to be applied in various 5G scenarios, including machine-to-machine communications and the Internet of Things. Concerns of the present disclosure include the use of NOMA for grant-free uplink transmissions and retransmission schemes such uplink transmissions.

Brief Description of the Drawings

[0005] FIG. 1 is a block diagram of a radio architecture in accordance with some embodiments.

[0006] FIG. 2 il lustrates a front-end module circuitry for use in the radio architecture of FIG. 1 in accordance with some embodiments.

[0007] FIG. 3 illustrates a radio IC circuitry for use in the radio architecture of FIG. 1 in accordance with some embodiments.

[0008] FIG 4 illustrates a baseband processing circuitry for use in the radio architecture of FIG.1 in accordance with some embodiments.

[0009] FIG. 5 illustrates an example of a computing machine such as an evolved Node B (eNB) or next generation evolved node B (gNB) according to some embodiments.

[0010] FIG. 6 illustrates an example of a user equipment (UE) device according to some embodiments.

[0011] FIG. 7 illustrates an example UE and a base station (BS) such as an eNB or gNB according to some embodiments.

[0012] FIG. 8 il lustrates a UL NOMA transmission scheme that includes a preamble, a control channel, and a data channel.

[0013] FIG. 9 illustrates a UL NOMA transmission scheme that included a preamble and a data channel.

[0014] FIGS. 10A, 10B, IOC, and 10D illustrate alternative ways of transmitting a preamble, a control channel, and a data channel. [0015] FIGS. 1 1 A and 1 IB illustrate alternative ways of transmitting a preamble and a data channel.

Detailed Description

[0016] In conventional grant-based transmission schemes such as are commonly used in orthogonal multiple access (OMA) schemes, a user sends a scheduling request to the base station (BS) and, based on the received request, the BS performs scheduling for the uplink transmission and sends an uplink (UL) grant over the downlink (DL) channel. This procedure results in large latency and high signaling cost that increases in the situations of massive connectivity anticipated for 5G In contrast, such dynamic scheduling is not required in grant-free UL NOMA schemes to result in a drastic reduction in transmission latency and signaling overhead. Grant- free UL transmissions based on non-orthogonal multiple access (NOMA) may be considered as applicable various use cases including massive connectivity for machine type communication (MTC) and low overhead UL transmission schemes that minimize device power consumption for transmission of small data packets.

[0017] One of the key characteristics of grant-free transmissions includes the selection of resources for the transmission of the UL packets. As the term is used herein, a multiple access (MA) physical resource for grant-free or other UL NOMA transmission is comprised of a time-frequency block or resource of a modulation scheme. For example, the MA physical resource may be a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers. An MA resource is comprised of a MA physical resource and a MA signature, where a MA signature may include at least one of the following: codebook/codeword, sequence, interleaver and/or mapping pattern, demodulation reference signal (DM-RS), preamble, spatial dimension, or power dimension.

[0018] In this disclosure, methods, apparatus, and mechanisms are described for MA resource configuration and MA resource selection in the context of grant-free UL transmission. Also, given the lack of accurate link adaptation as compared to what is available in scheduled grant-based UL transmissions and the inherent contention- based multiple access mechanism of grant-free transmissions, it is important that grant-free schemes support retransmission opportunities to improve the reliability of the transmissions. Depending on the grant-free transmission mechanisms, various considerations need to be accounted for the support of retransmissions and hybrid automatic repeat request (HARQ). Also described herein are methods and apparatus that incorporate retransmission and HARQ schemes for grant-free UL NOMA transmissions.

Example Radio Architecture

[0019] FIG. 1 is a block diagram of a radio architecture 100 in accordance with some embodiments. Radio architecture 100 may include radio front-end module (FEM) circuitry 104, radio IC circuitry 06 and baseband processing circuitry 108. Radio architecture 100 as shown includes both Wireless Local Area Network

(WLAN) functionality and Bluetooth (BT) functionality although embodiments are not so limited. In this disclosure, "WLAN" and "Wi-Fi" are used interchangeably, [0020] FEM circuitry 104 may include a WLAN or Wi-Fi FEM circuitry 104 A and a Bluetooth (BT) FEM circuitry 104B. The WLAN FEM circuitry 104B may include a receive signal path comprising circuitry configured to operate on WLAN RF signals received from one or more antennas 101, to amplify the received signals and to provide the amplified versions of the received signals to the WLAN radio IC circuitry 106 A for further processing. The BT FEM circuitry 104B may include a receive signal path which may include circuitry configured to operate on BT RF signals received from one or more antennas 102, to amplify the received signals and to provide the amplified versions of the received signals to the BT radio IC circuitry 106B for further processing. FEM circuitry 104A may also include a transmit signal path which may include circuitry configured to amplify WLAN signals provided by the radio IC circuitry 06 A for wireless transmission by one or more of the antennas 101. In addition, FEM circuitry 104B may also include a transmit signal path which may include circuitry configured to amplify BT signals provided by the radio IC circuitry 106B for wireless transmission by the one or more antennas. In the embodiment of FIG. 1, although FEM 104A and FEM 104B are shown as being distinct from one another, embodiments are not so limited, and include within their scope the use of an FEM (not shown) that includes a transmit path and/or a receive path for both WLAN and BT signals, or the use of one or more FEM circuitries where at least some of the FEM circuitries share transmit and/or receive signal paths for both WLAN and BT signals.

[0021] Radio IC circuitry 106 as shown may include WLAN radio IC circuitry 06 A and BT radio IC circuitry 106B. The WLAN radio IC circuitry 106a may include a receive signal path which may include circuitry to down-convert WLAN RF signals received from the FEM circuitry 104 A and provide baseband signals to WLAN baseband processing circuitry 108 A. BT radio IC circuitry 106B may in turn include a receive signal path which may include circuitry to down-convert BT RF signals received from the FEM circuitry 104B and provide baseband signals to BT baseband processing circuitry 108B, WLAN radio IC circuitry 106 A may also include a transmit signal path which may include circuitry to up-convert WLAN baseband signals provided by the WLAN baseband processing circuitry 108A and provide WLAN RF output signals to the FEM circuitry 104 A for subsequent wireless transmission by the one or more antennas 101. BT radio IC circuitry 106B may also include a transmit signal path which may include circuitry to up-convert BT baseband signals provided by the BT baseband processing circuitry 108B and provide BT RF output signals to the FEM circuitry 104B for subsequent wireless transmission by the one or more antennas 101. In the embodiment of FIG. 1, although radio IC circuitries 106A and 106B are shown as being distinct from one another, embodiments are not so limited, and inciude within their scope the use of a radio IC circuitry (not shown) that includes a transmit signal path and/or a receive signal path for both WLAN and BT signals, or the use of one or more radio IC circuitries where at least some of the radio IC circuitries share transmit and/or receive signal paths for both WLAN and BT signals.

[0022] Baseband processing circuity 108 may include a WLAN baseband processing circuitry 108 A and a BT baseband processing circuitry 108B. The WLAN baseband processing circuitry 108 A may include a memory, such as, for example, a set of RAM arrays in a Fast Fourier Transform or Inverse Fast Fourier Transform block (not shown) of the WLAN baseband processing circuitry 108 A. Each of the WLAN baseband circuitry 108 A and the BT baseband circuitry 108B may further include one or more processors and control logic to process the signals received from the corresponding WL AN or BT receive signal path of the radio IC circuitry 106, and to also generate corresponding WLAN or BT baseband signals for the transmit signal path of the radio IC circuitry 106. Each of the baseband processing circuitries 108A and 108B may further include physical layer (PHY) and medium access control layer (MAC) circuitry, and may further interface with application processor 110 for generation and processing of the baseband signals and for controlling operations of the radio IC circuitry 106.

[0023] Referring still to FIG. 1, according to the shown embodiment, WLAN-BT coexistence circuitry 113 may include logic providing an interface between the WLAN baseband circuitry 108 A and the BT baseband circuitry 108B to enable use cases requiring WLAN and BT coexistence. In addition, a switch 103 may be provided between the WLAN FEM circuitry 104 A and the BT FEM circuitry 104B to allow switching between the WLAN and BT radios according to application needs. In addition, although the antennas 101 are depicted as being respectively connected to the WLAN FEM circuitry 104 A and the BT FEM circuitry 104B, embodiments include within their scope the sharing of one or more antennas as between the WLAN and BT FEMs, or the provision of more than one antenna connected to each of FEM 104 A or 104B.

[0024] In some embodiments, the front-end module circuitry 104, the radio IC circuitry 106, and baseband processing circuitry 108 may be provided on a single radio card, such as wireless radio card 102. In some other embodiments, the one or more antennas 101, the FEM circuitry 104 and the radio IC circuitry 106 may be provided on a single radio card. In some other embodiments, the radio IC circuitry 106 and the baseband processing circuitry 108 may be provided on a single chip or integrated circuit (IC), such as IC 1 12.

[0025] In some embodiments, the wireless radio card 102 may include a WLAN radio card and may be configured for Wi-Fi communications, although the scope of the embodiments is not limited in this respect. In some of these embodiments, the radio architecture 100 may be configured to receive and transmit orthogonal frequency division multiplexed (OFDM) or orthogonal frequency division multiple access (OFDMA) communication signals over a multicarrier communication channel. The OFDM or OFDMA signals may comprise a plurality of orthogonal subcarriers.

[0026] In some of these multicarrier embodiments, radio architecture 100 may be part of a Wi-Fi communication station (ST A) such as a wireless access point ( AP), a base station or a mobile device includ ing a Wi-Fi device. In some of these embodiments, radio architecture 100 may be configured to transmit and receive signals in accordance with specific communication standards and/or protocols, such as any of the Institute of Electrical and Electronics Engineers (IEEE) standards including, 802.1 ln-2009, IEEE 802, 11-2012, 802.1 ln-2009, 802.1 lac, and/or

802.1 lax standards and/or proposed specifications for WLANs, although the scope of embodiments is not limited in this respect. Radio architecture 100 may also be suitable to transmit and/or receive communications in accordance with other techniques and standards.

[0027] In some embodiments, the radio architecture 100 may be configured for high-efficiency (HE) Wi-Fi (HEW) communications in accordance with the IEEE 802.1 lax standard. In these embodiments, the radio architecture 100 may be configured to communicate in accordance with an OFDMA technique, although the scope of the embodiments is not limited in this respect.

[0028] In some other embodiments, the radio architecture 100 may be configured to transmit and receive signals transmitted using one or more other modulation techniques such as spread spectrum modulation (e.g., direct sequence code division multiple access (DS-CDMA) and/or frequency hopping code division multiple access (FH-CDMA)), time-division multiplexing (TDM) modulation, and/or frequency- division multiplexing (FDM) modulation, although the scope of the embodiments is not limited in this respect.

[0029] In some embodiments, as further shown in FIG. 1 , the BT baseband circuitry 108B may be compliant with a Bluetooth (BT) connectivity standard such as Bluetooth, Bluetooth 4.0 or Bluetooth 5.0, or any other iteration of the Bluetooth Standard. In embodiments that include BT functionality as shown for example in Fig. 1, the radio architecture 100 may be configured to establish a BT synchronous connection oriented (SCO) link and or a BT low energy (BT LE) link. In some of the embodiments that include functionality, the radio architecture 100 may be configured to establish an extended SCO (eSCO) link for BT communications, although the scope of the embodiments is not limited in this respect. In some of these embodiments that include a BT functionality, the radio architecture may be configured to engage in a BT Asynchronous Connection-Less (ACL) communications, although the scope of the embodiments is not limited in this respect. In some embodiments, as shown in FIG. 1, the functions of a BT radio card and WLA radio card may be combined on a single wireless radio card, such as single wireless radio card 102, although

embodiments are not so limited, and include within their scope discrete WLAN and BT radio cards

[0030] In some embodiments, the radio-architecture 100 may include other radio cards, such as a cellular radio card configured for cellular (e.g., 3 GPP such as LTE, LTE- Advanced or 5G communications).

[0031] In some IEEE 802.1 1 embodiments, the radio architecture 100 may be configured for communication over various channel bandwidths including bandwidths having center frequencies of about 900 MHz, 2.4 GHz, 5 GHz, and bandwidths of about 1 MHz, 2 MHz, 2.5 MHz, 4 MHz, 5ΜΉζ, 8 MHz, 10 MHz, 16 MHz, 20 MHz, 40MHz, 80MHz (with contiguous bandwidths) or 80+80MHz (160MHz) (with noncontiguous bandwidths). In some embodiments, a 320 MHz channel bandwidth may be used. The scope of the embodiments is not limited with respect to the above center frequencies however.

[0032] FIG. 2 il lustrates FEM circuitry 200 in accordance with some

embodiments. The FEM circuitry 200 is one example of circuitry that may be suitable for use as the WLAN and/or BT FEM circuitry I 04A/104B (FIG. 1 ), although other circuitry configurations may also be suitable.

[0033] In some embodiments, the FEM circuitry 200 may include a TX/RX switch 202 to switch between transmit mode and receive mode operation. The FEM circuitry 200 may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry 200 may include a low-noise amplifier (LNA) 206 to amplify received RF signals 203 and provide the amplified received RF signals 207 as an output (e.g., to the radio IC circuitry 106 (FIG. 1)). The transmit signal path of the circuitry 200 may include a power amplifier (PA) to amplify input RF signals 209 (e.g., provided by the radio IC circuitry 106), and one or more filters 212, such as band-pass filters (BPFs), low-pass filters (LPFs) or other types of filters, to generate RF signals 215 for subsequent transmission (e.g., by one or more of the antennas 101 (FIG. 1)).

[0034] In some dual-mode embodiments for Wi-Fi communication, the FEM circuitry 200 may be configured to operate in either the 2.4 GHz frequency spectrum or the 5 GHz frequency spectrum. In these embodiments, the receive signal path of the FEM circuitry 200 may include a receive signal path duplexer 204 to separate the signals from each spectrum as well as provide a separate LNA 206 for each spectrum as shown. In these embodiments, the transmit signal path of the FEM circuitry 200 may also include a power amplifier 210 and a filter 212, such as a BPF, a LPF or another type of filter for each frequency spectrum and a transmit signal path duplexer 214 to provide the signals of one of the different spectrums onto a single transmit path for subsequent transmission by the one or more of the antennas 101 (FIG. 1). In some embodiments, BT communications may utilize the 2.4 GHZ signal paths and may utilize the same FEM circuitry 200 as the one used for WLA communications, [0035] FIG. 3 illustrates radio IC circuitry 300 in accordance with some embodiments. The radio IC circuitry 300 is one example of circuitry that may be suitable for use as the WLAN or BT radio IC circuitry 106A/106B (FIG. 1), although other circuitry configurations may also be suitable.

[0036] In some embodiments, the radio IC circuitry 300 may include a receive signal path and a transmit signal path. The receive signal path of the radio IC circuitry 300 may include at least mixer circuitry 302, such as, for example, down- conversion mixer circuitry, amplifier circuitry 306 and filter circuitry 308. The transmi t signal path of the radio IC circuitry 300 may include at least filter circuitry 312 and mixer circuitry 314, such as, for example, up-conversion mixer circuitry. Radio IC circuitry 300 may also include synthesizer circuitry 304 for synthesizing a frequency 305 for use by the mixer circuitry 302 and the mixer circuitry 3 4. The mixer circuitry 302 and/or 314 may each, according to some embodiments, be configured to provide direct conversion functionality. The latter type of circuitry presents a much simpler architecture as compared with standard super-heterodyne mixer circuitries, and any flicker noise brought about by the same may be alleviated for example through the use of OFDM modulation. FIG. 3 illustrates only a simplified version of a radio IC circuitry, and may include, although not shown, embodiments where each of the depicted circuitries may include more than one component. For instance, mixer circuitry 320 and/or 314 may each include one or more mixers, and filter circuitries 308 and/or 312 may each include one or more filters, such as one or more BPFs and/or LPFs according to application needs. For example, when mixer circuitries are of the direct-conversion type, they may each include two or more mixers. [0037] In some embodiments, mixer circuitry 302 may be configured to down- convert RF signals 207 received from the FEM circuitry 104 (FIG. 1) based on the synthesized frequency 305 provided by synthesizer circuitry 304. The amplifier circuitry 306 may be configured to amplify the down-converted signals and the filter circuitry 308 may include a LPF configured to remove unwanted signals from the down-converted signals to generate output baseband signals 307. Output baseband signals 307 may be provided to the baseband processing circuitry 108 (FIG. 1) for further processing. In some embodiments, the output baseband signals 307 may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 302 may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0038] In some embodiments, the mixer circuitry 314 may be configured to up- convert input baseband signals 3 J 1 based on the synthesized frequency 305 provided by the synthesizer circuitry 304 to generate RF^' output signals 209 for the FEM circuitry 104. The baseband signals 311 may be provided by the baseband processing circuitry 108 and may be filtered by filter circuitry 312, The filter circuitry 312 may include a LPF or a BPF, although the scope of the embodiments is not limited in this respect,

[0039] In some embodiments, the mixer circuitry 302 and the mixer circuitry 314 may each include two or more mixers and may be arranged for quadrature down- conversion and/or up-conversion respectively with the help of synthesizer 304. In some embodiments, the mixer circuitry 302 and the mixer circuitry 314 may each include two or more mixers each configured for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 302 and the mixer circuitry 314 may be arranged for direct down-conversion and/or direct up-conversion,

respectively. In some embodiments, the mixer circuitry 302 and the mixer circuitry 314 may be configured for super-heterodyne operation, although this is not a requirement.

[0040] Mixer circuitry 302 may comprise, according to one embodiment:

quadrature passive mixers (e.g., for the in-phase (I) and quadrature phase (Q) paths). In such an embodiment, RF input signal 207 from Fig, 3 may be down-converted to provide I and Q baseband output signals to be sent to the baseband processor [0041] Quadrature passive mixers may be driven by zero and ninety degree time- varying LO switching signals provided by a quadrature circuitry which may be configured to receive a LO frequency (fLo) from a local oscillator or a synthesizer, such as LO frequency 305 of synthesizer 304 (FIG. 3). In some embodiments, the LO frequency may be the carrier frequency, while in other embodiments, the LO frequency may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the zero and ninety degree time- varying switching signals may be generated by the synthesizer, although the scope of the embodiments is not limited in this respect,

[0042] In some embodiments, the LO signals may differ in duty cycle (the percentage of one period in which the LO signal is high) and/or offset (the difference between start points of the period). In some embodiments, the LO signals may have a 25% duty cycle and a 50% offset. In some embodiments, each branch of the mixer circuitry (e.g., the in-phase (I) and quadrature phase (Q) path) may operate at a 25% duty cycle, which may result in a significant reduction is power consumption.

[0043] The RF input signal 207 (FIG. 2) may comprise a balanced signal, although the scope of the embodiments is not limited in this respect. The I and Q baseband output signals may be provided to low-nose amplifier, such as amplifier circuitry 306 (FIG. 3) or to filter circuitry 308 (FIG. 3).

[0044] In some embodiments, the output baseband signals 307 and the input baseband signals 311 may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals 307 and the input baseband signals 311 may be digital baseband signals. In these alternate embodiments, the radio IC circuitry may include analog-to- digital converter (ADC) and digital-to-analog converter (DAC) circuitry.

[0045] In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, or for other spectrums not mentioned here, although the scope of the embodiments is not limited in this respect.

[0046] In some embodiments, the synthesizer circuitry 304 may be a fractional-N synthesizer or a fractional N/N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 304 may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider. According to some embodiments, the synthesizer circuitry 304 may include digital synthesizer circuitry. An advantage of using a digital synthesizer circuitry is that, although it may still include some analog components, its footprint may be scaled down much more than the footprint of an analog synthesizer circuitry. In some embodiments, frequency input into synthesizer circuity 304 may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. A divider control input may further be provided by either the baseband processing circuitry 108 (FIG. 1) or the application processor 1 10 (FIG. 1) depending on the desired output frequency 305, In some embodiments, a divider control input (e.g., N) may be determined from a look-up table (e.g., within a Wi-Fi card) based on a channel number and a channel center frequency as determined or indicated by the application processor 1 10.

[0047] In some embodiments, synthesizer circuitry 304 may be configured to generate a carrier frequency as the output frequency 305, while in other embodiments, the output frequency 305 may be a fraction of the carrier frequency (e.g., one-half the carrier frequency, one-third the carrier frequency). In some embodiments, the output frequency 305 may be a LO frequency (fLo).

[0048] FIG. 4 illustrates a functional block diagram of baseband processing circuitry 400 in accordance with some embodiments. The baseband processing circuitry 400 is one example of circuitry that may be suitable for use as the baseband processing circuitry 108 (FIG. 1), although other circuitry configurations may also be suitable. The baseband processing circuitry 400 may include a receive baseband processor (RX BBP) 402 for processing receive baseband signals 309 provided by the radio IC circuitry 106 (FIG. 1) and a transmit baseband processor (TX BBP) 404 for generating transmit baseband signals 311 for the radio IC circuitry 106. The baseband processing circuitry 400 may also include control logic 406 for coordinating the operations of the baseband processing circuitry 400.

[0049] In some embodiments (e.g., when analog baseband signals are exchanged between the baseband processing circuitry 400 and the radio IC circuitry 106), the baseband processing circuitry 400 may include ADC 10 to convert analog baseband signals received from the radio IC circuitry 106 to digital baseband signals for processing by the RX BBP 402. In these embodiments, the baseband processing circuitry 400 may also include DAC 412 to convert digital baseband signals from the TX BBP 404 to analog baseband signals.

[0050] In some embodiments that communicate OFDM signals or OFDMA signals, such as through baseband processor 108a, the transmit baseband processor 404 may be configured to generate OFDM or OFDMA signals as appropriate for transmission by performing an inverse fast Fourier transform ( H i ! ) The receive baseband processor 402 may be configured to process received OFDM signals or OFDMA signals by performing an FFT. In some embodiments, the receive baseband processor 402 may be configured to detect the presence of an OFDM signal or OFDMA signal by performing an autocorrelation, to detect a preamble, such as a short preamble, and by performing a cross-correlation, to detect a long preamble. The preambles may be part of a predetermined frame structure for Wi-Fi communication.

[0051] Referring back to FIG. 1, in some embodiments, the antennas 101 (FIG. 1) may each comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, microstrip antennas or other types of antennas suitable for transmission of RF signals. In some multiple-input multiple-output (ΜΓΜΟ) embodiments, the antennas may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result. Antennas 101 may each include a set of phased-array antennas, although embodiments are not so limited.

[0052] Although the radio-architecture 00 is illustrated as having several separate functional elements, one or more of the functional elements may be combined and may be implemented by combinations of software-configured elements, such as processing elements including digital signal processors (DSPs), and/or other hardware elements. For example, some elements may comprise one or more microprocessors, DSPs, field-programmable gate arrays (FPGAs), application specific integrated circuits (ASICs), radio-frequency integrated circuits (RFICs) and combinations of various hardware and logic circuitry for performing at least the functions described herein. In some embodiments, the functional elements may refer to one or more processes operating on one or more processing elements.

Example Machine Description [0053] FIG. 5 illustrates a block diagram of an example machine 500 upon which any one or more of the techniques (e.g., methodologies) discussed herein may performed. In alternative embodiments, the machine 500 may operate as a standalone device or may be connected (e.g., networked) to other machines. In a networked deployment, the machine 500 may operate in the capacity of a server machine, a client machine, or both in server-client network environments. In an example, the machine 500 may act as a peer machine in peer-to-peer (P2P) (or other distributed) network environment. The machine 500 may be a user equipment (UE), evolved Node B (eNB), next generation evolved Node B (gNB), next generation access network (AN), next generation user plane function (UPF), Wi-Fi access point (AP), Wi-Fi station (STA), personal computer (PC), a tablet PC, a set-top box (STB), a personal digital assistant (PDA), a mobile telephone, a smart phone, a web appliance, a network router, switch or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Further, while only a single machine is illustrated, the term "machine" shall also be taken to include any collection of machines that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster

configurations.

[0054] Examples, as described herein, may include, or may operate on, logic or a number of components, modules, or mechanisms. Modules are tangible entities (e.g., hardware) capable of performing specified operations and may be configured or arranged in a certain manner. In an example, circuits may be arranged (e.g., internally or with respect to external entities such as other circuits) in a specified manner as a module. In an example, the whole or part of one or more computer systems (e.g., a standalone, client or server computer system) or one or more hardware processors may be configured by firmware or software (e.g., instaictions, an application portion, or an application) as a module that operates to perform specified operations. In an example, the software may reside on a machine readable medium. In an example, the software, when executed by the underlying hardware of the module, causes the hardware to perform the specified operations.

[0055] Accordingly, the term "module" is understood to encompass a tangible entity, be that an entity that is physically constructed, specifically configured (e.g., hardwired), or temporarily (e.g., transitorily) configured (e.g., programmed) to operate in a specified manner or to perform part or all of any operation described herein. Considering examples in which modules are temporarily configured, each of the modules need not be instantiated at any one moment in time. For example, where the modules comprise a general-purpose hardware processor configured using software, the general-purpose hardware processor may be configured as respective different modules at different times. Software may accordingly configure a hardware processor, for example, to constitute a particular module at one instance of time and to constitute a different module at a different instance of time,

[0056] Machine (e.g., computer system) 500 may include a hardware processor 502 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 504 and a static memory 506, some or all of which may communicate with each other via an interlink (e.g., bus) 508. The machine 500 may further include a display unit 5 10, an alphanumeric input device 512 (e.g., a keyboard), and a user interface (UI) navigation device 514 (e.g., a mouse). In an example, the display unit 510, input device 512 and UI navigation device 514 may be a touch screen display. The machine 500 may additionally include a storage device (e.g., drive unit) 516, a signal generation device 518 (e.g., a speaker), a network interface device 520, and one or more sensors 521, such as a global positioning system (GPS) sensor, compass, accelerometer, or other sensor. The machine 500 may include an output controller 528, such as a serial (e.g., universal serial bus (USB), parallel, or other wired or wireless (e.g., infrared (IR), near field communication (NFC), etc.) connection to communicate or control one or more peripheral devices (e.g., a printer, card reader, etc.).

[0057] The storage device 516 may include a machine readable medium 522 on which is stored one or more sets of data structures or instructions 524 (e.g., software) embodying or utilized by any one or more of the techniques or functions described herein. The instructions 524 may also reside, completely or at least partially, within the main memory 504, within static memory 506, or within the hardware processor 502 during execution thereof by the machine 500. In an example, one or any combination of the hardware processor 502, the main memory 504, the static memory 506, or the storage device 5 6 may constitute machine readable media. [0058] While the machine readable medium 522 is illustrated as a single medium, the term "machine readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and/or associated caches and servers) configured to store the one or more instructions 524.

[0059] The term "machine readable medium" may include any medium that is capable of storing, encoding, or carrying instructions for execution by the machine 500 and that cause the machine 500 to perform any one or more of the techniques of the present disclosure, or that is capable of storing, encoding or carrying data structures used by or associated with such instructions. Non-limiting machine readable medium examples may include solid-state memories, and optical and magnetic media. Specific examples of machine readable media may include: nonvolatile memory, such as semiconductor memory devices (e.g., Electrically

Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and flash memory devices; magnetic disks, such as internal hard disks and removable disks; magneto-optical disks; Random Access

Memory (RAM), and CD-ROM and DVD-ROM disks. In some examples, machine readable media may include non-transitory machine readable media. In some examples, machine readable media may include machine readable media that is not a transitory propagating signal.

[0060] The instructions 524 may further be transmitted or received over a communications network 526 using a transmission medium via the network interface device 520 utilizing any one of a number of transfer protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Example communication networks may include a local area network (LAN), a wide area network (WAN), a packet data network (e.g., the Internet), mobile telephone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., Institute of Electrical and Electronics Engineers (IEEE) 802. 1 1 family of standards known as Wi- Fi®, IEEE 802.16 family of standards known as WiMax®), IEEE 802.15.4 family of standards, a Long Term Evolution (LTE) family of standards, a Universal Mobile Telecommunications System (UMTS) family of standards, peer-to-peer (P2P) networks, among others. In an example, the network interface device 520 may include one or more physical jacks (e.g., Ethernet, coaxial, or phone jacks) or one or more antennas to connect to the communications network 526. In an example, the network interface device 520 may include a plurality of antennas to wirelessly communicate using at least one of single-input multiple-output (SIMO), multiple- input multiple-output (MIMO), or multiple-input single-output (MISO) techniques. In some examples, the network interface device 520 may wirelessly communicate using Multiple User MIMO techniques. The term "transmission medium" shall be taken to include any intangible medium that is capable of storing, encoding, or carrying instructions for execution by the machine 500, and includes digital or analog communications signals or other intangible medium to facilitate communication of such software.

Example I ^'/'^■.^' Description

[0061] As used herein, the term "circuitry" may refer to, be part of, or include an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group), and/or memory (shared, dedicated, or group) that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable hardware components that provide the described functionality. In some embodiments, the circuitry may be implemented in, or functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, circuitry may include logic, at least partially operable in hardware.

[0062] Embodiments described herein may be implemented into a system using any suitably configured hardware and/or software. FIG. 6 illustrates, for one embodiment, example components of a User Equipment (UE) device 600. In some embodiments, the UE device 600 may include application circuitry 602, baseband circuitry 604, Radio Frequency (RF) circuitry 606, front-end module (FEM) circuitry 608 and one or more antennas 610, coupled together at least as shown.

[0063] The application circuitry 602 may include one or more application processors. For example, the application circuitry 602 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The processor(s) may include any combination of general-purpose processors and dedicated processors (e.g., graphics processors, application processors, etc.). The processors may be coupled with and/or may include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications and/or operating systems to run on the system.

[0064] The baseband circuitry 604 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. The baseband circuitry 604 may include one or more baseband processors and/or control logic to process baseband signals received from a receive signal path of the RF circuitry 606 and to generate baseband signals for a transmit signal path of the RF circuitry 606. Baseband processing circuity 604 may interface with the application circuitry 602 for generation and processing of the baseband signals and for controlling operations of the RF circuitry 606. For example, in some embodiments, the baseband circuitry 604 may include a second generation (2G) baseband processor 604a, third generation (3G) baseband processor 604b, fourth generation (4G) baseband processor 604c, and/or other baseband processor(s) 604d for other existing generations, generations in development or to be developed in the future (e.g., fifth generation (5G), 6G, etc.). The baseband circuitry 604 (e.g., one or more of baseband processors 604a-d) may handle various radio control functions that enable communication with one or more radio networks via the RF circuitry 606. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency shifting, etc. In some embodiments, modulation/demodulation circuitry of the baseband circuitry 604 may include Fast-Fourier Transform (FFT), precoding, and/or constellation mapping/demapping functionality. In some embodiments, encoding/decoding circuitry of the baseband circuitry 604 may include convolution, tail-biting convolution, turbo, Viterbi, and/or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functionality are not limited to these examples and may include other suitable functionality in other embodiments.

[00651 In some embodiments, the baseband circuitry 604 may include elements of a protocol stack such as, for example, elements of an evolved universal terrestrial radio access network (EUTRAN) protocol including, for example, physical (PHY), media access control (MAC), radio link control (RLC), packet data convergence protocol (PDCP), and/or radio resource control (RRC) elements. A central processing unit (CPU) 604e of the baseband circuitry 604 may be configured to run elements of the protocol stack for signaling of the PH Y, MAC, RLC, PDCP and/or RRC layers. In some embodiments, the baseband circuitry may include one or more audio digital signal processor(s) (DSP) 604f. The audio DSP(s) 604f may be include elements for compression/decompression and echo cancellation and may include other suitable processing elements in other embodiments. Components of the baseband circuitry may be suitably combined in a single chip, a single chipset, or disposed on a same circuit board in some embodiments. In some embodiments, some or all of the constituent components of the baseband circuitry 604 and the application circuitry 602 may be implemented together such as, for example, on a system on a chip (SOC).

[0066] In some embodiments, the baseband circuitry 604 may provide for communication compatible with one or more radio technologies. For example, in some embodiments, the baseband circuitry 604 may support communication with an evolved universal terrestrial radio access network (EUTRA ) and/or other wireless metropolitan area networks (WMAN), a wireless local area network (WLAN), a wireless personal area network (WPAN). Embodiments in which the baseband circuitry 604 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry,

[0067] RF circuitry 606 may enable communication with wireless networks using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 606 may include switches, filters, amplifiers, etc. to facilitate the communication with the wireless network. RF circuitry 606 may include a receive signal path which may include circuitry to down-convert RF signals received from the FEM circuitry 608 and provide baseband signals to the baseband circuitry 604. RF circuitry 606 may also include a transmit signal path which may include circuitry to up-convert baseband signals provided by the baseband circuitry 604 and provide RF output signals to the FEM circuitry 608 for transmission.

[0068] In some embodiments, the RF circuitry 606 may include a receive signal path and a transmit signal path. The receive signal path of the RF circuitry 606 may include mixer circuitry 606a, amplifier circuitry 606b and filter circuitry 606c. The transmit signal path of the RF circui try 606 may include filter circuitry 606c and mixer circuitry 606a. RF circuitry 606 may also include synthesizer circuitry 606d for synthesizing a frequency for use by the mixer circuitry 606a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 606a of the receive signal path may be configured to down-convert RF signals received from the FEM circuitry 608 based on the synthesized frequency provided by synthesizer circuitry 606d. The amplifier circuitry 606b may be configured to amplify the down- converted signals and the filter circuitry 606c may be a low-pass filter (LPF) or bandpass filter (BPF) configured to remove unwanted signals from the down-converted signals to generate output baseband signals. Output baseband signals may be provided to the baseband circuitry 604 for further processing. In some embodiments, the output baseband signals may be zero-frequency baseband signals, although this is not a requirement. In some embodiments, mixer circuitry 606a of the receive signal path may comprise passive mixers, although the scope of the embodiments is not limited in this respect.

[0069] In some embodiments, the mixer circuitry 606a of the transmit signal path may be configured to up-convert input baseband signals based on the synthesized trequency provided by the synthesizer circuitry 606d to generate RF output signals for the FEM circuitry 608. The baseband signals may be provided by the baseband circuitry 604 and may be filtered by filter circuitry 606c. The filter circuitry 606c may include a low-pass filter (LPF), although the scope of the embodiments is not limited in this respect.

[0070] In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may include two or more mixers and may be arranged for quadrature downconversion and/or upconversion respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may include two or more mixers and may be arranged for image rejection (e.g., Hartley image rejection). In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a may be arranged for direct downconversion and/or direct upconversion, respectively. In some embodiments, the mixer circuitry 606a of the receive signal path and the mixer circuitry 606a of the transmit signal path may be configured for super-heterodyne operation.

[0071] In some embodiments, the output baseband signals and the input baseband signals may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternate embodiments, the output baseband signals and the input baseband signals may be digital baseband signals. In these alternate embodiments, the RF circuitry 606 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and the baseband circuitry 604 may include a digital baseband interface to communicate with the RF circuitry 606.

[0072] In some dual-mode embodiments, a separate radio IC circuitry may be provided for processing signals for each spectrum, although the scope of the embodiments is not limited in this respect.

[0073] In some embodiments, the synthesizer circuitry 606d may be a fractional- N synthesizer or a fractional N N+l synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, synthesizer circuitry 606d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer comprising a phase-locked loop with a frequency divider,

[0074] The synthesizer circuitry 606d may be configured to synthesize an output frequency for use by the mixer circuitry 606a of the RF circuitry 606 based on a frequency input and a divider control input. In some embodiments, the synthesizer circuitry 606d may be a fractional N N+l synthesizer.

[0075] In some embodiments, frequency input may be provided by a voltage controlled oscillator (VCO), although that is not a requirement. Divider control input may be provided by either the baseband circuitry 604 or the applications processor 602 depending on the desired output frequency. In some embodiments, a divider control input (e.g., N) may be determined from a look-up table based on a channel indicated by the applications processor 602.

[0076] Synthesizer circuitry 606d of the RF circuitry 606 may include a divider, a delay-locked loop (DLL), a multiplexer and a phase accumulator. In some embodiments, the divider may be a dual modulus divider (DMD) and the phase accumulator may be a digital phase accumulator (DP A). In some embodiments, the DMD may be configured to divide the input signal by either N or N+l (e.g., based on a carry out) to provide a fractional division ratio. In some example embodiments, the DLL may include a set of cascaded, tunable, delay elements, a phase detector, a charge pump and a D-type flip-flop. In these embodiments, the delay elements may be configured to break a VCO period up into Nd equal packets of phase, where Nd is the number of delay elements in the delay line. In this way, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle. [0077] In some embodiments, synthesizer circuitry 606d may be configured to generate a carrier frequency as the output frequency, while in other embodiments, the output frequency may be a multiple of the carrier frequency (e.g., twice the carrier frequency, four times the carrier frequency) and used in conjunction with quadrature generator and divider circuitry to generate multiple signals at the carrier frequency with multiple different phases with respect to each other. In some embodiments, the output frequency may be a LO frequency (tio)- In some embodiments, the RF circuitry 606 may include an IQ/polar converter.

[0078] FEM circuitry 608 may include a receive signal path which may include circuitry configured to operate on RF signals received from one or more antennas 610, amplify the received signals and provide the amplified versions of the received signals to the RF circuitry 606 for further processing. FEM circuitry 608 may also include a transmit signal path which may include circuitry configured to amplify signals for transmission provided by the RF circuitry 606 for transmission by one or more of the one or more antennas 610.

[0079] In some embodiments, the FEM circuitry 608 may include a TX/RX switch to switch between transmit mode and receive mode operation. The FEM circuitry may include a receive signal path and a transmit signal path. The receive signal path of the FEM circuitry may include a low-noise amplifier (LNA) to amplify received RF signals and provide the amplified received RF signals as an output (e.g., to the RF circuitry 606). The transmit signal path of the FEM circuitry 608 may include a power amplifier (PA) to amplify input RF signals (e.g., provided by RF circuitry 606), and one or more filters to generate RF signals for subsequent transmission (e.g., by one or more of the one or more antennas 610.

[0080] In some embodiments, the UE device 600 may include additional elements such as, for example, memory/storage, display, camera, sensor, and/or input/output (I/O) interface.

Description of Embodiments for Grant-free UL NOMA

[0081] In Long Term Evolution (LTE) and 5G systems, a mobile terminal

(referred to as a User Equipment or UE) connects to the cellular network via a base station (BS), referred to as an evolved Node B or eNB in LTE systems and as a next generation evolved Node B or gNB in 5G systems. FIG. 7 illustrates an example of the components of a UE 1400 and a base station (e.g., eNB or gNB) 1300. The BS 1300 includes processing circuitry 1301 connected to a radio transceiver 1302 for providing an air interface. The UE 1400 includes processing circuitry 1401 connected to a radio transceiver 1402 for providing an air interface over the wireless medium. Each of the transceivers in the devices is connected to antennas 1055. The memory and processing circuitries of the UE and/or BS may be configured to perform the functions and implement the schemes of the various embodiments described herein.

[0082] Current LTE systems and 5G systems may utilize orthogonal frequency division multiple access (OFDM A) based on orthogonal frequency division multiplexing (OFDM) for the downlink (DL) and a related technique, single carrier frequency division multiple access (SC-FDMA) based on DFT pre-coded OFDM, for the uplink (UL). OFDMA may also be used for the uplink in some 5G systems. In the embodiments described herein for UL NOMA, the modulation schemes may any multi-carrier or single-carrier modulation scheme including, but not limited to, OFDM, DFT pre-coded OFDM, time-division multiplexing, frequency-division multiplexing, and code division multiplexing. Also, as the terms are used herein, a slot is some specified number of modulation symbol durations (i.e., a slot comprises N modulation symbols where N is an integer), a subframe is some specified number of slots, and a frame is some specified number of subframes.

[0083] Described herein are mechanisms, apparatus, and methods for MA resource configuration, MA resource selection, and A retransmissions for grant-free UL transmission. These include various details related to the following: 1) grant-free UL transmission procedure and MA resource composition, 2) contents of the control message and the packet header, 3) MA resource pool configuration, 4) MA resource selection mechanisms including selection, determination, and configuration of MA physical resources and MA signatures, 5) MA physical resource configuration including virtual resources and time-frequency-hopped resources, 6) synchronous hybrid automatic repeat request (HARQ) schemes, 7) asynchronous retransmission schemes, and 8) hybrid HARQ schemes with preamble/control channel transmission. Grant-free UL NOMA transmission procedures and MA resource composition

[0084] Grant-free UL transmission schemes need to ensure that the identification of the transmission parameters (e.g., MCS/TBS), identification of the UE for purpose of decoding at the Physical layer (e.g., knowledge of the MA signature),

synchronization, and channel estimation can be determined or detected by the Base Station (BS, also referred to as the eNodeB (eNB) or gNodeB (gNB)) receiver.

Accordingly, various procedures for grant-free transmissions can be considered towards achieving these goals, and corresponding to the possible procedures, the grant-free UL NOMA transmissions can be composed accordingly of one or more physical channels or signals. Such components possibly include presence of a preamble that can facilitate UE identification (at least part of the MA signature can be conveyed by the preamble), a control channel to provide information about the transmission parameters and possibly at least a part of the MA signature to the BS receiver, and the data channel that actually carries the encoded user data and headers. Note that while the contents can be specific to the control and the data channels respectively, the physical layer structure and the NOMA spreading scheme can be common for both the control and data channels.

[0085] Two broad options may be considered for UL NOMA transmissions where the distinction is based on the presence or not of a control channel. In Option 1 , as illustrated by FIG. 8, physical layer transmission parameters such as modulation and coding scheme (MCS), transport block size (TBS), MA signature, and MA resource are explicitly signaled by the control channel. In this option, a dedicated control channel 800 is transmitted between the preamble 700 and data channel 800. The BS may detect the preamble initially for synchronization/channel estimation purposes. The BS may also determine certain information (e.g., the MA resource and at least a part of the MA signature) from the preamble for decoding the control channel. The BS may then decodes the control channel for MCS/TBS, MA signature, and other control information for data channel reception.

[0086] In Option 2, as illustrated by FIG. 9, physical layer transmission parameters such as MCS/TBS, MA signature, etc., are implicitly derived. In this option, a dedicated control channel is not needed, and only a preamble 700 and a data channel 900 are transmitted. MCS/TBS and MA signature information may be derived from preamble and/or implicitly derived from resource pool partition. The BS may detect the preamble and determine certain information (e.g.,

TBS/MCS/resource) for data channel transmission. [0087] Compared to Option 2, Option 1 can facilitate support of flexible set of transmission parameters, including different MCS, TBS values, and number of repetitions, at the cost of UL resource overhead and interference from transmission of the control channel , the other hand, Option 2 may be appropriate for use cases with a more limited set of packet sizes and traffic characteristics, such that it may be feasible for the BS to be able to blindly detect a much smaller subset of transmission parameters or even use the preamble and/or resource pool partition and/or other MA signature options to convey such information. For instance, in one embodiment, the combination of MCS, TBS, and number of repetitions can be reduced by fixing the MCS and allowing a few values of TBS and time domain repetitions.

[0088] Further, for Option 1 in which a control channel is transmitted, the following alternatives can be considered to realize different procedures for UL grant- tree transmissions designated as Alt. 1-1 through Alt. 1-4 and illustrated by FIGS. 10A through 10D, respectively. In Alt. 1-1 as illustrated by FIG. 10A, the preamble 700, control channel, 800, and data channel 900 are transmitted within a unified resource unit or set of resource units. This corresponds to a "single-step" grant-free UL transmission scheme wherein failure in preamble detection can lead to inability in decoding the data packet or resource waste for control and data transmission within the same resource unit. In Alt. 1-2 as illustrated bv FIG 10B, the control channel 800 is transmitted together with the preamble 700 and both of these are separate from the data channel. Thus, the overall MA resource would correspond to two distinct components: 1) preamble and 2) control and data channel. Accordingly, the BS can provide feedback in the DL to the specific LIE in the event of successful detection of the corresponding preamble. In Alt. 1-3 as illustrated by FIG IOC, the preamble 700 is separately transmitted from the control channel 800 and data channel 900, with the latter two (control and data parts) transmitted based on either FDM or TDM based multiplexing, similar to Alt. 1-2, the BS can provide feedback in the DL

corresponding to successful detection of the preamble and decoding of the control channel. Furthermore, it may also be possible for the BS to dynamically determine the scheme and parameters for the actual data transmission and indicate that to the UE, similar to scheduled user data transmissions. In Alt. 1- 4 as illustrated by FIG 10D, shows a transmission scheme for UL NOMA similar to the current random access channel (RACFI) procedure specified in LTE. The preamble 700 (Msg, 1), control channel 800 (Msg3), and data channel 900 are transmitted separately with potential feedback from the BS after each of the component transmission from the UE - preamble, control channel, and data channel.

[0089] For alternatives Alt. 1-2, Alt. 1-3, and Alt. 1-4, where the preamble and control channel are separately transmitted, the resource indication at least for the control channel and possibly also the data channel (e.g., for Alt. 1-3 above) can be provided by the preamble. Such a resource indication may be either: 1) entirely uniquely specified/configured following a one-to-one mapping, 2) partly

configured/determined following a one-to-many mapping, wherein the UE selects the resources for control and/or data transmission based on a random resource selection from a subset of resources, or 3) partly configured/determined following a group-level or many-to-one or many-to-many mapping. Furthermore, for cases with control channel transmission, the control and data channels may not be multiplexed via code division multiplexing (CDM). Thus at least data can be scheduled from control (for data) or from (preamble sequence) where the resources used for transmission are selected randomly from a pool of resources,

[0090] For the case of Option 2, i.e., without control message transmission, all phy sical layer parameters/configuration needed for decoding of the data packets need to be conveyed by the preamble and or determined blindly by the BS or a combination of both. Alternatively, NOM A transmissions can be supported only for a certain combination of MCS/TBS/repetitions and MA signatures and we may need to rely on resource pool partitioning to keep the BS receiver complexity surmountable. Similar to the case of Option 1, two alternatives for Option 2 may be described, designated as Alt. 2-1 and Alt. 2-2 as shown in FIGS. 1 1 A and J IB, respectively. In Alt. 2-1 as illustrated by FIG 11 A, the preamble 700 and data channel 900 are transmitted as part of the same resource. In this case, the BS receiver may jointly detect the preamble and any DM-RS present within the resource for data channel. In Alt. 2-2 as illustrated by FIG 1 IB the preamble 700 and data channel 900 are transmitted on separate resources. In this embodiment, the MCS/TBS may be implicitly derived from resource pool or from preamble, the MA signature may be derived from UE ID or preamble ID, the BS may first detect the preamble and then decode data based on the determined MA signature, and the BS may feedback an acknowledgement (ACK) upon successful preamble detection. [0091] For all alternatives (under either Option 1 or 2), where the preamble and control and/or data transmission are on contiguous set of physical resources or transmitted as part of the same physical resource, the preamble functionality can be realized by additional DM-RS symbols. At the receiver, both preamble and actual DM-RS may be used for channel estimation and for packet demodulation. As one example, assuming a LTE PUSCH DM-RS design, the preamble functionality can be realized by having one or more DM-RS symbols right before the transmission of the data transmission with or without a time gap between the end of the preamble part and the beginning of the data transmission.

Contents of the control message and the packet header

[0092] The control message can convey various important transmission parameters including: MCS/TBS, MA signature, HARQ information including HARQ process ID and retransmission number. On the other hand, the contents of the header that may be carried as part of the user data transmission may include the LIE-ID and MAC control elements such as a power headroom report (PHR) or buffer status report (BSR).

MA resource pool configuration

[0093] The MA resource pool may comprise one or more MA resources, and thus, is a combination of at least a MA physical resource pool and a MA signature pool. Here, a MA physical resource corresponds to at least the resources used for transmission of the data packet and the associated DM-RS. However, depending on the resource selection and assignment/pre-configuration options, in some

embodiments, only one of the MA physical resource pool and MA signature pool may be known to the UE. For instance, as discussed in the following section, it may be possible to pre-configure the UE with MA signature, and it may only need to perform MA physical resource selection from a configured MA physical resource pool.

[0094] An individual MA physical resource, defined as a time-frequency block, can span multiple PRBs and/or multiple subframes. As an example, for support of enhanced radio coverage, the smallest schedulable resource amount in the frequency domain (e.g., a physical resource block (PRB) or one or more subcarriers) and multiple subframes or slots in time can be configured as an MA physical resource. Further, when transmitting using multiple time-domain resources (e.g., subframes, slots), the transport block (TB) may either be transmitted with repetitions over the multiple time domain resources or be directly mapped to multiple subframes, or a combination of both.

[0095] For the grant-free UL transmission mechanisms employing preamble or control channel, for the cases wherein these are transmitted as separate transmissions (as described in the previous section), the corresponding resource pools may be configured separately as well, wherein a separate resource pool comprising of a collection of individual physical resources corresponding to each of a preamble, control channel, and data channel transmission can be configured. Alternatively, the resources for at least a subset of these physical signals and channels may have a predefined linkage, implying a single resource pool for the corresponding transmission components. For instance, the preamble and the control channel may be transmitted maintaining a pre-defined time-frequency relationship for their corresponding physical resources from a single resource pool (in other words, an individual resource in this case comprises of both the physical resource for preamble transmission and the physical resource for the control channel transmission). The example Alt. 1-2 illustrated by FIG. 10B can be seen as a particular special case of this where the preamble and the control channel are transmitted contiguously in time. The resource pool may be configured to include multiple individual resources in both frequency and time that may occur periodically or even as a set of persistently occurring resources, with the exact configuration being up to the BS.

MA resource selection mechanisms including selection/determitiaiwn/c^' onfigiiration of MA physical resources and MA signatures

[0096] MA resource selection can be realized in various ways to grant-free UL transmissions, considering the determination of MA physical resources for data channel, MA physical resources for preamble and/or control (if preamble and/or control message are used), MA signature. Some of these could be selected randomly or pre-configured or determined based on resource selection/determination of some other components of MA resource. An example of the last case is when the resource used for preamble transmission is determined based on the resource selected for the data transmission or vice versa. Some further details are elaborated below.

MA signature selection

[0097] The MA signature selection implies UE's selection or determination of a particular MA signature from a pool of available signatures for a MA signature type

(e.g., DM-RS sequence, preamble sequence, spreading code, mterleaver-pattern, etc.).

This can be a function of one or more of: the time/frequency physical resource index,

UE identity (where the complete UE identity is conveyed as part of the encoded data packet), preamble or DM-RS sequence index (if only a part of the MA signature is conveyed by the preamble or DM-RS sequence), cell ID, etc. As one example, the choice of MA signature (maSignature_i) can be described as:

maSignature i = f (UE-ID mod. X, maPhyResource index, cell ID), where f () is a deterministic or pseudorandom function. As another alternative, the preamble sequence and possibly also the preamble physical resource can be selected randomly by the UE and detected blindly at the BS receiver, and the MA signature can be determined as a deterministic function of the preamble sequence and possibly the preamble phy sical resource.

[0098] In case of preamble based grant-free UL transmissions, the preamble transmission separate from the data packet transmission can support a hierarchical hand-shake based mechanism where the BS gets an opportunity to provide feedback in response to the preamble transmission. Such a mechanism can provide more robust BS reception and HARQ support as the BS would be made aware of the UE identity necessary for data packet demodulation before the data is actually transmitted,

[0099] However, one challenge towards supporting a large number of

simultaneous connections is that the sequence space for preambles need to be sufficiently large and at the same time not, cause significant system overhead or overburden the BS receiver. Towards this, in one embodiment, the preamble design is based on a multi-step (at least two-step) preamble design, such that the preamble comprises of two or more sequences, thereby allowing a larger number of candidates to be indicated by a combination of the respective sequence for the first and subsequent parts of the preamble. [00100] As an example, the preamble may be composed of two parts: Preamble 1 and Preamble__2 that jointly indicate the transmission characteristics or identification needed for physical layer decoding, with the following possible relationships between them. Preamble 2 sequence is a function of the Preamble 1 sequence with 1 -to-many mapping. Note that for a 1-to-l mapping, no additional information can be conveyed by the use of two-part preamble. Preamble 2 sequence is independent of Preamble 1 sequence. The combination can then convey the identity need for packet decoding.

[00101] In one example, preamble 1 and preamble 2 sequences can be designed based on Zadoff-Chu sequences or a computer-generated sequences with low Peak to Average Power Ratio (PAPR) or Cubic Metric (CM). Similar to DM-RS as defined in LTE, preamble_l and preamble_2 sequences consist of a base sequence and a cyclic shifted version of the base sequence. To reduce BS detection complexity, the root index for the preamble I sequence can be defined as a function of one or more of: physical or virtual cell ID, subframe/slot/symbol index and UE may randomly select one cyclic shift value for corresponding preamble 1 transmission. As a second step, root index of preamble_2 may be defined as a function of at least the cyclic shift value selected in the preamble _1. Further, the UE may randomly select one cyclic shift value for the corresponding preamble_2 transmission. For this design option, a linkage or one-to-many mapping between preamble _1 and preamble 2 can be established, which can help to reduce detection complexity at the BS side.

MA physical resource selection

[00102] Similar methods as described for MA signature selection can be applied for MA physical resource selection as well, and different combinations between the two can be realized. For instance, the MA physical resources can be: 1) randomly selected for data transmission, preamble, and control message transmission, if the latter are supported; 2) randomly selected for one of data, preamble, and control transmission, and the others determined in a deterministic manner; 3) randomly selected only for preamble and possibly also for control, with the rest determined based on BS response to the preamble/control transmission (this method would apply for multi-step grant-free transmission methods described earlier); 4) the above could also be realized based on deterministic or pseudorandom mappings from the MA signature selection (if the MA signature selection is performed independently) instead of being selected randomly from the MA physical resource pool. Further, the option of deterministic mapping from the MA signature to the MA physical resource may only be applied if the MA signature determination is random or pseudorandom (i.e., not pre-configured or deterministic in order to avoid consistent collisions between UEs).

[00103] For the selection of the MA physical resource from the bigger resource pool, the selection can be performed not only from the set of available frequency domain resources but also over a certain time window 'W\ The time window 'W can be less than or equal to the time domain extent of the resource pool itself (e.g., W = N if the resource pool comprises of M PRBs and N subframes with a periodic occurrence every P subframes where P > N). The selection over a time window provides a natural "backing off' mechanism as against the method wherein the UE selects on the frequency resource once a packet is available at the transmit buffer.

[00104] The time window size ' W may be configured by the BS as part of the resource pool configuration and indicated via cell-specific common control transmissions (e.g., System Information Block (SIB) signaling). For retransmission attempts, the size of the window could be increased by factors of 2ⁿ for n = 0, 1, 2, indicating the initial transmission, first retransmission, second retransmission, etc. MA physical resource configuration including virtual resources and time-frequency- hopped resources

[00105] For transmissions spanning multiple time units (e.g., subframes or slots), in one embodiment, time-frequency hopping is used in defining an individual MA physical resource in order to improve the robustness based on diversity gains and possibly also interference randomization. Thus, the MA physical resources, MA physical resource pool, and MA physical resource selection or configuration can be defined in terms of "logical" or "virtual" MA resources where the mapping from logical resources to physical resources is achieved by the time-frequency hopping patterns.

[00106] The time-frequency hopping can be either deterministic (to enable combining of the received packets) or pseudorandom (to provide interference randomization) or a combination of the above. If the TB is directly mapped onto multiple time domain resources, then a deterministic relationship is necessary to enable the reception of the complete transport block. However, for repetition-based mapping of the TB to multiple time domain resources, the time-frequency hopping can be based on a pseudorandom hopping pattern.

Retransmission and HARQ Schemes for Grant-free UL NOMA.

[00107] In the following sections, retransmission and HARQ schemes for grant- free UL NOMA transmissions are described. These embodiments include methods and apparatus for synchronous HARQ, asynchronous retransmissions, and a hybrid HARQ mechanism. Additionally, resource mapping from prior to subsequent retransmission in case of adaptations of the transmission parameters during

retransmissions are addressed based on configuration of a plurality of M A resource pools.

Synchronous HARQ

[00108] For grant-free transmissions from a UE, the base station (BS) (may also be referred to as eNodeB (eNB) or g odeB (gNB)) may or may not be aware of the UE's identity until the packet is successfully decoded. Thus, only an acknowledgement- based response mechanism can be supported, wherein the gNB indicates a positive acknowledgment (ACK) in response to a successfully decoded packet. Accordingly, in case of no detection of an ACK corresponding to the initial transmission, the UE can make subsequent transmission attempts.

[00109] Following the ACK response-based retransmission scheme, in one embodiment, the resource used for retransmission is a deterministic function of the index of the MA physical resource within the MA physical resource pool that was used for the initial transmission. This implies that, depending on the exact MA resource pool configuration, although the exact resource used for retransmission may not maintain a fixed timing relationship with respect to the initial transmission on an absolute time scale, the instance of retransmission opportunity and at least the MA physical resource used can be known beforehand at the UE and the gNB receiver without explicit indication from the gNB, thereby implying a synchronous HARQ mechanism. [00110] As one example, the MA physical resource index in time domain relative to the MA physical resource pool, e.g., the slot or subframe index or the starting subframe index (in case of NOMA transmissions using multiple subframes), for retransmission attempt #i (maResourceInB^' me(i)), with i ^::= 1, 2, is given by: maResourcelnTime (i) = maResourcelnTime (i-l) ÷ moReTxDelay, where the parameter maReTxDekty is configured via higher layers and is defined in terms of available valid subframes or valid starting subframes for UL NOMA transmissions. Alternatively, the retransmission delay can be specified to a fixed value, or pre-defined as a function of the cell ID or one or more parameters of MA signatures if MA signature is configured by higher layers. Similarly, the frequency location for the resource used for retransmission can be determined as a deterministic function of the initial resource location. In this case, frequency hopping can be applied for the retransmission resources to realized frequency diversity gains.

[00111] It should be noted that the time-frequency resource location for retransmission may be defined as function of both time and frequency location of the prior transmission attempt. In one example, the following may be an alternative way to determine the time domain index for the retransmission resource: maResourcelnTime (i) g (maResourcelnTime (i-l), maResourcelnFreq (i-l), moReTxDelqy), where maResourcelnFreq (i-l) indicates the frequency resource index used to identify the MA physical resource, and g( ) is a pre-determined or pseudorandom function of the cell ID, the latter to provide inter-cell interference randomization. Alternatively, g() can be initialized as a function of one or more parameters in MA signature if MA signature is configured by higher layers. Asynchronous HARQ [00112] While the above allows for soft combining at the gNB receiver, it may not improve the effective SINR due to consistent collisions, i .e., if the initial packet decoding failure was a result of high interference and multiple UEs were not decoded successfully, retransmissions from these UEs on the same resources may not significantly improve the probability of decoding success. In order to provide an additional mechanism of interference randomization, the synchronous HARQ mechanism can be modified to an asynchronous version such that the exact resource used for a retransmission is randomly picked from a subset of resources or pseudo- randomly defined as a function of a UE-specific parameter that may include one or more of: UE ID, MA signature used in the prior transmission attempt.

[00113] Therefore, according to this approach, the UE can pre-determine the resource for retransmission without any indication from the gNB; however, this information may not be available at the gNB receiver, hence, soft combining across retransmission attempts may not be possible. As an example, the time domain index for the retransmission resource can be defined as: maResourceln ime (i) = maResourcelnTime .'"/·· I) ÷ maReTxDelay + randomOffsetln Time, where randomOffsetlnTime is a random time offset in units of symbol durations, slots, subframes, or multiples thereof, drawn from a uniform distribution within a range [0, W], The parameter W, defining the range, can be configured by the gNB as part of the MA resource pool configuration or be specified. Note that the parameter W may be doubled for every K retransmissions, where K can be predefined in the specification or configured by higher layers. Further, the frequency domain index for the retransmission resource may be defined similar to the time domain index as mentioned above so as to realize the benefit of frequency diversity.

[00114] In one embodiment, both synchronous and asynchronous retransmissions can be supported and can be configured as part of the MA physical resource pool configuration by the gNB in a semi-static manner. As a further extension, eNB or gNB may disable or enable one of synchronous or asynchronous retransmission modes via broadcast message. This may help for interference management and loading control. Hybrid HARQ mechanism for grant-free transmissions with preamble and/or control channel

[00115] For the case of grant-free UL NOMA transmissions using a preamble and/or control channel transmission in addition to the data transmission, a hybrid between synchronous and asynchronous HARQ can be supported assuming higher reliability and robustness can be achieved for the preamble or control channel compared to the data channel, e.g., the data channel encoding and MCS usage may be less robust compared to the control channel.

[00116] Specifically, synchronous HARQ may be applied only for the preamble and/or control channel transmission, but not for the data part. Accordingly, only the resources used for retransmission of preamble and/or the control channel transmission are determined according to a synchronous mechanism to enable combining at the gNB receiver across retransmission attempts. In contrast, the resources used for data transmission can be picked either randomly or pseudo-randomly based on UE-speeific parameters as described above, thereby following an asynchronous HARQ scheme. In this case, the actual resource used for data transmission can be indicated by the preamble or the control channel information, thereby also allowing for combining of the data part based on information obtained from the detection of the preamble or decoding of the control channel.

[00117] For the above to be beneficial, the preamble or control channel transmission should use a more robust transmission scheme compared to the data transmission. Accordingly, the retransmissions for the preamble and/or control channel can be decoupled from those of the data transmissions. Thus, the preamble and/or control channel may require fewer retransmission attempts compared to the data channel.

Resource pools for retransmission attempts

[00118] If power ramping or repetition level ramping or adjustments to MCS are supported for retransmissions, the resource for retransmission may be drawn from a pool of resources that is independent from the prior transmission. Such consideration may be beneficial in order to avoid detrimental effects of near-far effects due to drastically different transmission power levels or require more complicated receiver implementation to handle overlaps of different MCS or repetition levels. [00119] Therefore, different MA resource pools may be configured corresponding to the transmission power (e.g., different resource pools for UEs transmitting with maximum transmission power and those using power control), or the coverage or repetition level (which can be determined based on DL measurements). Thus, the MA physical resource selected for retransmission should be from the appropriate M A physical resource pool, if retransmissions use different transmission parameters like power control, number of repetitions, or MCS. In such cases, synchronous HARQ can still be supported by defining the appropriate mapping of the MA physical resource index from resource pool used for prior transmission to the resource pool used for the subsequent retransmission.

Additional Notes and Examples

In Example 1, an apparatus for a user equipment (UE) comprises: memory and processing circuitry; wherein the memory and processing circuitry are to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOMA) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOM A transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another UE using the same selected MA physical resource; wherein the memory is configured to store data for retrieval and inclusion in the initial grant-free UL NOMA transmission; and, if no acknowledgement (ACK) has been received for the initial UL NOMA transmission during a specified timeout period, select an MA physical resource and MA signature for an UL NOMA retransmission of the data as a function of the MA physical resource and MA signature used for the initial UL NOMA transmission to synchronize the UL NOM A retransmission with the initial UL NOMA transmission.

[00120] In Example la, the subject matter of any of the Examples herein may optionally include wherein the MA signature is a transmission pattern selected from one or a combination of transmission patterns distinguished by: codeword mapping from a codebook, spreading sequence, interleaving or mapping pattern, scrambling pattern, demodulation reference signals (DM-RSs), preamble, spatial transmission pattern, repetition pattern, and/or transmission power level.

[00121] In Example lb, the subject matter of any of the Examples herein may optionally include wherein the timeout is a specified or configurable parameter.

[00122] In Example 2, the subject matter of Example 1 or any of the Examples herein may optionally include wherein the processing circuitry is to: if no

acknowledgement (ACK) has been received for a UL NOMA retransmission during a timeout period, select an MA physical resource and MA signature for a subsequent UL NOMA retransmission of the data as a function of the MA physical resource and MA signature used for the prior UL NO A retransmission to synchronize the subsequent UL NOMA retransmission with the prior UL NOMA retransmission; continue to select MA physical resources and MA signatures for subsequent UL NOMA retransmissions when no ACK has been received for the prior UL NOMA retransmission up until a specified maximum number of retransmissions.

[00123] In Example 3, the subject matter of Example 1 or any of the Examples herein may optional ly include wherein the processing circuitry is to encode UL NOMA retransmissions with a redundancy version of the data to enable soft combining by the BS.

[00124] In Example 4, the subject matter of Example 1 or any of the Examples herein may optionally include wherein the MA time domain resource and/or MA frequency domain resource for UL NOMA retransmissions are predetermined without explicit indication from the BS.

[00125] In Example 5, the subject matter of Example 1 or any of the Examples herein may optionally include wherein the starting MA time domain resource for each successive UL NOMA retransmission due to non-receipt of an ACK is delayed by the value of a parameter maReTxDelay from the starting time domain resource of the immediately previous initial UL NOMA transmission or NOMA retransmission.

[00126] In Example 6, the subject matter of Example 1 or any of the Examples herein may optional ly include wherein the maReTxDelay is configured by the BS.

[00127] In Example 7, the subject matter of Example 1 or any of the Examples herein may optionally include wherein the starting MA time domain resource for a retransmission attempt designated as an index maResourcelnTime(i) relative to the MA physical resource pool with ^;=: 1 , 2, ...designating successive transmissions, is calculated as:

maResourcelnTime (i) — maResourcelnTime + maReTxDelay

where maReTxDelay is parameter that is either predefined or configured by the BS.

[00128] In Example 8, the subject matter of Example 7 or any of the Examples herein may optionally include wherein the parameter maReTxDelay is configured by the BS and defined in terms of available valid subframes or valid starting sub frames for UL NOMA transmissions.

[00129] In Example 9, the subject matter of Example 7 or any of the Examples herein may optionally include wherein the retransmission delay parameter maReTxDelay is specified as a fixed value, defined as a function of a cell

identification (ID), or defined as a function of one or more parameters of an MA signature configured by the BS.

[00130] In Example 10, the subject matter of Example 2 or any of the Examples herein may optionally include wherein the MA frequency domain resource used for a NOMA retransmission is determined as a function of the MA frequency domain resource used for the initial UL NOMA transmission or prior NOMA retransmission.

[00131] In Example 11, the subject matter of Example 2 or any of the Examples herein may optionally include wherein the MA time and frequency domain resources for a NOMA retransmission are defined as functions of the MA time and frequency domain resources used in a prior transmission attempt.

[00132] In Example 12, an apparatus for a user equipment (UE) comprises:

memory and processing circuitry; wherein the memory and processing circuitry are to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOMA) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOMA transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another UE using the same selected MA physical resource, wherein the memory is configured to store data for retrieval and incl sion in the initial grant- free UL NOMA transmission; and, if no acknowledgement (ACK) has been received for the initial UL NOMA transmission during a timeout period, select in a random or pseudo-random manner one or more of the MA time domain resource, the MA frequency domain resource, and MA signature for an UL NOMA retransmission.

[00133] In Example 13, the subject matter of Example 12 or any of the Examples herein may optionally include wherein the processing circuitry is to: if no

acknowledgement (ACK) has been received for a UL NOMA retransmission during a specified timeout period, select in a random or pseudo-random manner one or more of the MA time domain resource, the MA frequency domain resource, and MA signature for a subsequent UL NOMA retransmission of the data; and, continue to select MA physical resources and MA signatures for subsequent UL NOMA retransmissions when no ACK has been received for the prior UL NOM A retransmission up until a specified maximum number of retransmissions.

[00134] In Example 14, the subject matter of Example 13 or any of the Examples herein may optionally include wherein the starting MA time domain resource for a retransmission attempt /, designated as an index maResotircelriTime(i) relative to the MA physical resource pool with i ^:;= 1, 2, ...designating successive transmissions, is calculated as:

moResourcelnTime (i) = m ResourcelnTime + maReTxDel y+ randomOffsetlnTime

where randoinOffsetinTime is a random time offset in units of subframes, slots, symbol durations, or multiples of thereof drawn from a uniform distribution within a range [0, WJ where W is an integer,

[00135] In Example 15, the subject matter of Example 14 or any of the Examples herein may optionally include wherein the parameter W is configured by the BS as part of the A resource pool configuration or is predefined.

[00136] In Example 16, the subject matter of Example 14 or any of the Examples herein may optionally include wherein the parameter W is doubled for every K.

retransmissions, where K is predefined or configured by the BS.

[00137] In Example 17, an apparatus for a user equipment (UE) comprises:

memory and processing circuitry; wherein the memory and processing circuitry are to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOMA) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOM A transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another UE using the same selected MA physical resource; wherein the memory is configured to store data for retrieval and inclusion in the initial grant- free UL NOMA transmission; operate in either an asynchronous retransmission mode or a synchronous retransmission mode; when operating in an asynchronous retransmission mode, if no acknowledgement (ACK) has been received for the initial UL NOMA transmission during a specified timeout period, select in a random or pseudo-random manner one or more of the MA time domain resource, the MA frequency domain resource, and MA signature for an UL NOMA retransmission; and, when operating in a synchronous retransmission mode, if no acknowledgement (ACK) has been received for the initial UL NOMA transmission during a specified timeout period, select an MA physical resource and MA signature for an UL NOMA retransmission of the data as a function of the MA physical resource and MA signature used for the initial UL NOMA transmission to synchronize the UL NOMA retransmission with the initial UL NOMA transmission.

[00138] In Example 18, the subject matter of Example 17 or any of the Examples herein may optionally include wherein the processing circuitry is to: when operating in an asynchronous retransmission mode, if no acknowledgement (ACK) has been received for a UL NOMA retransmission during a specified timeout period, select in a random or pseudo-random manner one or more of the MA time domain resource, the MA frequency domain resource, and A signature for a subsequent UL NOMA retransmission of the data; when operating in synchronous retransmission mode, if no acknowledgement (ACK) has been received for a UL NOMA retransmission during a specified timeout period, select an MA physical resource and MA signature for a subsequent UL NOM A retransmission of the data as a function of the MA physical resource and MA signature used for the prior UL NOMA retransmission to synchronize the subsequent UL NOMA retransmission with the prior UL NOMA retransmission; and, continue to select MA physical resources and MA signatures for subsequent UL NOMA retransmissions when no ACK has been received for the prior UL NOMA retransmission up until a specified maximum number of retransmissions.

[00139] In Example 19, the subject matter of Example 17 or any of the Examples herein may optionally include wherein either synchronous retransmission mode or asynchronous retransmission mode is configured as part of the MA physical resource pool configuration by the BS in a semi-static manner.

[00140] In Example 20, the subject matter of Example 17 or any of the Examples herein may optional ly include wherein the synchronous or asynchronous

retransmission mode is enabled by broadcast message from the BS.

[00141] In Example 21 , the subject matter of Example 17 or any of the Examples herein may optionally include wherein the memory and processing circuitry are to: select an MA physical resource and MA signature for an UL NOMA preamble and/or control channel transmission occurs before the UL NOMA data transmission; and, wherein the preamble and/or control channel transmission indicates the MA physical resource used by the UL NOMA data transmission.

[00142] In Example 22, the subject matter of Example 71 or any of the Examples herein may optional ly include wherein the processing circuitry is to operate in a synchronous retransmission mode with respect to the preamble and/or control channel transmission and operate in an asynchronous retransmission mode with respect to the data transmission.

[00143] In Example 23, an apparatus for a user equipment (UE) comprises:

memory and processing circuitry; wherein the processing circuitry is to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOMA) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOMA transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another UE using the same selected MA physical resource; wherein the memory is configured to store data for retrieval and inclusion in the initial grant-free UL NOM A transmission; and select a physical resource for transmission of a preamble and/or control channel that occurs before transmission of the initial grant-free UL NOMA data transmission in a data channel.

[00144] In Example 24, the subject matter of Example 23 or any of the Examples herein may optionally include wherein the preamble and/or control channel transmission indicates the MA physical resource used by the UL NOM A data channel.

[00145] In Example 25, the subject matter of Example 23 or any of the Examples herein may optionally include wherein the processing circuitry is to, after

transmission of the preamble and/or control channel, await feedback from the BS before encoding the UL NOMA data channel.

[00146] In Example 26, the subject matter of Example 23 any of the Examples herein may optionally include wherein the processing circuitry of the UE is to retrieve from memory data for transmission in a data channel of UL NOMA transmission.

[00147] In Example 27, the subject matter of Example 23 any of the Examples herein may optionally include wherein the UL NOMA transmission is composed of one or more physical channels or signals.

[00148] In Example 28, the subject matter of Example 23 any of the Examples herein may optionally include wherein the one or more physical channels or signals include a preamble, a control channel to provide information about the transmission parameters and possibly at least a part of the MA signature to the BS receiver, and the data channel that actually carries the encoded user data and headers.

[00149] In Example 29, the subject matter of Example 23 any of the Examples herein may optionally include wherein the physical layer structure and the NOMA spreading scheme are common for both the control and data channels.

[00150] In Example 30, the subject matter of Example 23 any of the Examples herein may optionally include wherein the physical layer transmission parameters including MCS/TBS, MA signature, etc. are explicitly signaled by a control channel that is transmitted with preamble or data channel.

[00151] In Example 31, the subject matter of Example 23 any of the Examples herein may optionally include, wherein a preamble, control channel, and data channel are transmitted within a unified resource unit or set of resource units to realize a single-step grant-free UL transmission scheme. [00152] In Example 32, the subject matter of Example 23 any of the Examples herein may optionally include wherein control channel is transmitted together with the preamble and both of these are separate from the data channel.

[00153] In Example 33, the subject matter of Example 23 any of the Examples herein may optionally include wherein the preamble is separately transmitted from the control and data, with the latter two (control and data parts) transmitted based on either FDM or TDM based multiplexing.

[00154] In Example 34, the subject matter of Example 23 any of the Examples herein may optionally include wherein the preamble, control channel, and user data are transmitted separately with potential feedback from the BS after each of the component transmission from the UE - preamble, control channel, and user data, [00155] In Example 35, the subject matter of Example 23 any of the Examples herein may optionally include wherein the control and data channels are not multiplexed via code division multiplexing (CDM).

[00156] In Example 36, the subject matter of Example 23 any of the Examples herein may optionally include wherein when the preamble and control channel are separately transmitted, the resource indication at least for the control channel and possibly also the data channel are provided by the preamble.

[00157] In Example 37, the subject matter of Example 23 any of the Examples herein may optionally include wherein the physical layer transmission parameters such as the MCS/TBS and MA signature are implicitly derived and a dedicated control channel is not used.

[00158] In Example 38, the subject matter of Example 23 any of the Examples herein may optionally include wherein all physical layer parameters/configuration needed for decoding of the data packets are conveyed by the preamble and or are determined blindly by the BS or a combination of both.

[00159] In Example 39, the subject matter of Example 23 any of the Examples herein may optionally include wherein NOMA transmissions are supported only for a certain combination of MCS/TBS/repetitions and MA signatures and resource pool partitioning is used to limit the BS receiver complexity.

[00160] In Example 40, the subject matter of Example 23 any of the Examples herein may optionally include wherein the preamble and data are transmitted as part of the same resource. [00161] In Example 41, the subject matter of Example 23 any of the Examples herein may optionally include wherein the preamble and data are transmitted on separate resources.

[00162] In Example 42, the subject matter of Example 23 any of the Examples herein may optionally include wherein the preamble and control and/or data transmission are on contiguous set of physical resources or transmitted as part of the same physical resource and the preamble functionality is realized by additional OMRS symbols.

[00163] In Example 43, the subject matter of Example 23 any of the Examples herein may optionally include wherein at the BS receiver, both preamble and actual DM-RS are used for channel estimation for packet demodulation.

[00164] In Example 44, the subject matter of Example 23 any of the Examples herein may optionally include wherein the control channel conveys transmission parameters including one or more of: MCS/TBS, MA signature, HARQ information including HARQ process ID and retransmission number.

[00165] In Example 45, the subject matter of Example 23 any of the Examples herein may optionally include wherein the contents of the header that is carried as part of the user data transmission includes the UE-ID and MAC control elements like PHR or BSR.

[00166] The system and method of Claim 2, wherein the MA resource pool comprises of one or more MA resources, and thus, is a combination of at least a MA physical resource pool and a MA signature pool,

[00167] In Example 46, the subject matter of Example 23 any of the Examples herein may optionally include wherein a MA physical resource corresponds to at least the resources used for transmission of the data packet and the associated DM-RS.

[00168] In Example 47, the subject matter of Example 23 any of the Examples herein may optionally include wherein only one of the MA physical resource pool and MA signature pool is known to the LIE.

[00169] In Example 48, the subject matter of Example 23 any of the Examples herein may optionally include wherein an individual MA physical resource, defined as a time-frequency block, spans multiple PRBs and/or multiple subframes.

[00170] In Example 49, the subject matter of Example 23 any of the Examples herein may optionally include wherein for NOMA transmissions with preamble or control channel that are transmitted separately from data channel, the corresponding resource pools are configured separately with a separate resource pool comprising of a collection of individual physical resources corresponding to each of: preamble, control channel, and data channel transmission, is configured.

[00171] In Example 50, the subject matter of Example 23 any of the Examples herein may optionally include wherein the resources for at least a subset of the physical signals and channels maintain a pre-defined linkage.

[00172] In Example 51, the subject matter of Example 23 any of the Examples herein may optionally include wherein the MA signature selection is a function of one or more of: the time/frequency physical resource index, UE identity (where the complete UE identity is conveyed as part of the encoded data packet), preamble or DM-RS sequence index (if only a part of the MA signature is conveyed by the preamble or DM-RS sequence), cell ID, etc.

[00173] In Example 52, the subject matter of Example 23 any of the Examples herein may optionally include wherein the preamble sequence and possibly also the preamble physical resource are selected randomly by the UE and detected blindly at the BS receiver, and the MA signature is determined as a deterministic function of the preamble sequence and possibly the preamble physical resource,

[00174] In Example 53, the subject matter of Example 23 any of the Examples herein may optionally include wherein the preamble design is based on a multi-step (at least two-step) preamble design, such that the preamble comprises of two or more sequences or parts - Preamble _1 and Preamle 2, and both parts are used to jointly indicate one or more transmission characteristics or identification of the grant-free NOMA transmission.

[00175] In Example 54, the subject matter of Example 23 any of the Examples herein may optionally include wherein Preamble 2 sequence is a function of the Preamble_l sequence with 1 -to-many mapping, or, Preamble_2 sequence is independent of Preamble 1 sequence.

[00176] The system and method of Claim 28, wherein preamble_l and preamble_2 sequences are designed based on Zadoff-Chu sequences or computer-generated sequences with low Peak to Average Power Ratio (PAPR) or Cubic Metric (CM).

[00177] In Example 55, the subject matter of Example 23 any of the Examples herein may optionally include wherein the MA physical resource selection includes a combination of one or more of 1) random selection and deterministic mapping of the resources for the preamble, and 2) control and data channel transmission.

[00178] In Example 56, the subject matter of Example 23 any of the Examples herein may optionally include wherein for the selection of the MA physical resource from the bigger resource pool, the selection is performed not only from the set of available frequency domain resources but also over a certain time window W.

[00179] In Example 57, the subject matter of Example 23 any of the Examples herein may optionally include wherein the MA physical resources, MA physical resource pool, and MA physical resource selection or configuration can be defined in terms of "logical" or "virtual" MA resources where the mapping from logical resources to physical resources is achieved by the time-frequency hopping patterns.

[00180] In Example 58, the subject matter of Example 23 any of the Examples herein may optionally include wherein the time-frequency hopping is deterministic, pseudorandom, or a combination thereof.

[00181] In Example 59, an apparatus for a base station (BS) such as an eNB or gNB, comprises; memory and processing circuitry; wherein the memory and processing circuitry are to process UL NOMA transmissions encoded and transmitted according to any of the Examples herein to retrieve data in the data channel..

[00182] In Example 60, a computer-readable storage medium comprises instructions to cause a LIE or BS, upon execution of the instructions by the memory and processing circuitry of the UE or BS, to perform the functions of the memory and processing circuitry as recited by any of the Examples herein

[00183] In Example 61, the subject matter of any of the Examples herein may optionally include a radio transceiver having one or more antennas connected to the processing circuitry.

[00184] In Example 62, a method for operating a UE or BS comprises performing any of the functions of the processing circuitry and/or radio transceiver as recited by any of the Examples herein.

[00185] In Example 63, an apparatus for a UE or BS comprises means for performing any of the functions of the processing circuitry and/or radio transceiver as recited by any of the Examples herein. [00186] The above detailed description includes references to the accompanying drawings, which form a part of the detailed description. The drawings show, by way of illustration, specific embodiments that may be practiced. These embodiments are also referred to herein as "examples," Such examples may include elements in addition to those shown or described. However, also contemplated are examples that include the elements shown or described. Moreover, also contemplate are examples using any combination or permutation of those elements shown or described (or one or more aspects thereof), either with respect to a particular example (or one or more aspects thereof), or with respect to other examples (or one or more aspects thereof) shown or described herein.

[00187] Publications, patents, and patent documents referred to in this document are incorporated by reference herein in their entirety, as though individually incorporated by reference. In the event of inconsistent usages between this document and those documents so incorporated by reference, the usage in the incorporated reference(s) are supplementary to that of this document; for irreconcilable

inconsistencies, the usage in this document controls,

[00188] In this document, the terms "a" or "an" are used, as is common in patent documents, to include one or more than one, independent of any other instances or usages of "at least one" or "one or more." In this document, the term "or" is used to refer to a nonexclusive or, such that "A or B" includes "A but not B," "B but not A," and "A and B," unless otherwise indicated. In the appended claims, the terms "including" and "in which" are used as the plain-English equivalents of the respective terms "comprising" and "wherein." Also, in the following claims, the terms

"including" and "comprising" are open-ended, that is, a system, device, article, or process that includes elements in addition to those listed after such a term in a claim are still deemed to fall within the scope of that claim. Moreover, in the following claims, the terms "first," "second," and "third," etc. are used merely as labels, and are not intended to suggest a numerical order for their objects.

[00189] The embodiments as described above may be implemented in various hardware configurations that may include a processor for executing instructions that perform the techniques described. Such instructions may be contained in a machine- readable medium such as a suitable storage medium or a memory or other processor- executable medium. [00190] The embodiments as described herein may be implemented in a number of environments such as part of a wireless local area network (WLAN), 3rd Generation Partnership Project (3GPP) Universal Terrestrial Radio Access Network (UTRAN), or Long-Term-Evolution (LTE) or a Long-Term-Evolution (LTE) communication system, although the scope of the disclosure is not limited in this respect. An example LTE system includes a number of mobile stations, defined by the LTE specification as User Equipment (UE), communicating with a base station, defined by the LTE specifications as an eNodeB.

[00191] Antennas referred to herein may comprise one or more directional or omnidirectional antennas, including, for example, dipole antennas, monopole antennas, patch antennas, loop antennas, micro strip antennas or other types of antennas suitable for transmission of RF signals. In some embodiments, instead of two or more antennas, a single antenna with multiple apertures may be used. In these embodiments, each aperture may be considered a separate antenna. In some multiple- input multiple-output (MIMO) embodiments, antennas may be effectively separated to take advantage of spatial diversity and the different channel characteristics that may result between each of antennas and the antennas of a transmitting station. In some MIMO embodiments, antennas may be separated by up to 1/10 of a wavelength or more.

[00192] In some embodiments, a receiver as described herein may be configured to receive signals in accordance with specific communication standards, such as the Institute of Electrical and Electronics Engineers (IEEE) standards including IEEE 802.1 1-2007 and/or 802.1 1 (n) standards and/or proposed specifications for WLANs, although the scope of the disclosure is not limited in this respect as they may also be suitable to transmit and/or receive communications in accordance with other techniques and standards. In some embodiments, the receiver may be configured to receive signals in accordance with the IEEE 802.16-2004, the IEEE 802.16(e) and/or IEEE 802.16(m) standards for wireless metropolitan area networks (WMANs) including variations and evolutions thereof, although the scope of the disclosure is not limited in this respect as they may also be suitable to transmit and/or receive communications in accordance with other techniques and standards. In some embodiments, the receiver may be configured to receive signals in accordance with the Universal Terrestrial Radio Access Network (UTRAN) LTE communication standards. For more information with respect to the IEEE 802.11 and IEEE 802.16 standards, please refer to "IEEE Standards for Information Technology—

Telecommunications and Information Exchange between Systems" - Local Area Networks - Specific Requirements - Part 1 1 "Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY), ISO/IEC 8802-1 1 : 1999", and Metropolitan Area Networks - Specific Requirements - Part 16: "Air Interface for Fixed Broadband Wireless Access Systems," May 2005 and related amendments/versions. For more information with respect to UTRAN LTE standards, see the 3rd Generation

Partnership Project (3GPP) standards for UT AN- LTE, release 8, March 2008, including variations and evolutions thereof.

[00193] The above description is intended to be illustrative, and not restrictive. For example, the above-described examples (or one or more aspects thereof) may be used in combination with others. Other embodiments may be used, such as by one of ordinary skill in the art upon reviewing the above description. The Abstract is to allow the reader to quickly ascertain the nature of the technical disclosure, for example, to comply with 37 C.F.R. §1 .72(b) in the United States of America, It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. Also, in the above Detailed Description, various features may be grouped together to streamline the disclosure. However, the claims may not set forth every feature disclosed herein as embodiments may feature a subset of said features. Further, embodiments may include fewer features than those disclosed in a particular example. Thus, the following claims are hereby incorporated into the Detailed Description, with a claim standing on its own as a separate embodiment. The scope of the embodiments disclosed herein is to be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled.

Claims

1. An apparatus for a user equipment (UE), the apparatus comprising: memory and processing circuitry, wherein the processing circuitry is to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOMA) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOM A transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another UE using the same selected MA physical resource; wherein the memory is configured to store data for retrieval and incl sion in the initial grant-free UL NOMA transmission; and, if no acknowledgement (ACK) has been received for the initial grant-free UL NOMA transmission during a timeout period, select an MA physical resource and MA signature for an UL NO A retransmission of the data as a function of the MA physical resource and MA signature used for the initial grant-free UL NOMA transmission to synchronize the UL NOMA retransmission with the initial grant-tree UL NOMA transmission.

2. The apparatus of claim 1 wherein the processing circuitry is to: if no acknowledgement (ACK) has been received for a UL NOMA

retransmission during a specified timeout period, select an MA physical resource and MA signature for a subsequent UL NOMA retransmission of the data as a function of the MA physical resource and MA signature used for the prior UL NOMA retransmission to synchronize the subsequent UL NOMA retransmission with the prior UL NOMA retransmission; continue to select MA physical resources and MA signatures for subsequent UL NOMA retransmissions when no ACK has been received for the prior UL NOMA retransmission up until a specified maximum number of retransmissions.

3. The apparatus of claim 1 or 2 wherein the processing circuitry is to encode UL NOMA retransmissions with a redundancy version of the data to enable soft combining by the BS.

4, The apparatus of claim 1 or 2 wherein the MA time domain resource and/or MA frequency domain resource for UL NOMA retransmissions are predetermined without explicit indication from the BS.

5. The apparatus of claim 2 wherein the starting MA time domain resource for each successive UL NOMA retransmission due to non-receipt of an ACK is delayed by the value of a parameter oReTxDelay from the starting time domain resource of the immediately previous initial UL NOMA transmission or NOMA retransmission.

6. The apparatus of claim 5 wherein the maReTxDelay is configured by the BS.

7. The apparatus of claim 2 wherein the starting MA time domain resource for a retransmission attempt , designated as an index maResourcelnTime(i) relative to the MA physical resource pool with = 1, 2, ...designating successive transmissions, is calculated as: maResourcelnTime (i) = maResourcelnTime (i-l) + maReTxDelay where maReTxDeiay is parameter that is either predetmed or configured by the BS.

8. The apparatus of claim 7 wherein the parameter maReTxDeiay is configured by the BS and defined in terms of available valid subframes or valid starting subframes for UL NOMA transmissions.

9. The apparatus of claim 7 wherein the retransmission delay parameter maReTxDeiay is specified as a fixed value, defined as a function of a cell identification (ID), or defined as a function of one or more parameters of an MA signature configured by the BS.

10. The apparatus of claim 1 or 2 wherein the MA frequency domain resource used for a NOMA retransmission is determined as a function of the MA frequency domain resource used for the initial UL NOMA transmission or prior NOMA retransmission.

1. The apparatus of claim 1 wherein the MA signature is a transmission pattern selected from one or a combination of transmission patterns distinguished by: codeword mapping from a codebook, spreading sequence, interleaving or mapping pattern, scrambling pattern, demodulation reference signals (DM-RSs), preamble, spatial transmission pattern, repetition pattern, and/or transmission power level

12. An apparatus for a user equipment (LIE), the apparatus comprising: memory and processing circuitry; wherein the processing circuitry is to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOM A) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOMA transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another LIE using the same selected MA physical resource; wherein the memory is configured to store data for retrieval and inclusion in the initial grant-free UL NOMA transmission, and, if no acknowledgement (ACK) has been received for the initial UL NOMA transmission during a specified timeout period, select in a random or pseudo-random manner one or more of the MA time domain resource, the MA frequency domain resource, and MA signature for an UL NOMA retransmission.

13. The apparatus of claim 12 wherein the processing circuitry is to: if no acknowledgement (ACK) has been received for a UL NOMA

retransmission during a specified timeout period, select in a random or pseudorandom manner one or more of the MA time domain resource, the M A frequency domain resource, and MA signature for a subsequent UL NOMA retransmission of the data; and. continue to select MA physical resources and MA signatures for subsequent UL NOMA retransmissions when no ACK has been received for the prior UL NOMA retransmission up until a specified maximum number of retransmissions.

14. The apparatus of claim 13 wherein the starting MA time domain resource for a retransmission attempt i, designated as an index maResourcelnTime (i) relative to the MA physical resource pool with i = 1, 2, ...designating successive transmissions, is calculated as: maResourcelnTime (i) — maResourcelnTime + maReTxDelay+ ixmdomOffseilnTime where rcmdomOffsetlnTime is a random time offset in units of subframes, slots, symbol durations, or multiples of thereof drawn from a uniform distribution within a range 0, W] where W is an integer.

15. The apparatus of claim 14 wherein the parameter W is configured by the BS as part of the MA resource pool configuration or is predefined.

16. The apparatus of claim 14 wherein the parameter W is doubled for every K retransmissions, where K is predefined or configured by the BS.

17. An apparatus for a user equipment (LIE), the apparatus comprising: memory and processing circuitry; wherein the processing circuitry is to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOM A) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOMA transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another UE using the same selected MA physical resource; wherein the memory is configured to store data for retrieval and inclusion in the initial grant-free UL NOMA transmission; operate in either an asynchronous retransmission mode or a synchronous retransmission mode; when operating in an asynchronous retransmission mode, if no

acknowledgement (ACK) has been received for the initial UL NOMA transmission during a specified timeout period, select in a random or pseudo-random manner one or more of the MA time domain resource, the MA frequency domain resource, and MA signature for an UL NOMA retransmission; and, when operating in a synchronous retransmission mode, if no

acknowledgement (ACK) has been received for the initial UL NOMA transmission during a specified timeout period, select an MA physical resource and MA signature for an UL NOMA retransmission of the data as a function of the MA physical resource and MA signature used for the initial UL NOMA transmission to

synchronize the UL NOMA retransmission with the initial UL NOM A transmission. 8. The apparatus of claim 17 wherein the processing circuitry is to: when operating in an asynchronous retransmission mode, if no

acknowledgement (ACK) has been received for a UL NOMA retransmission during a specified timeout period, select in a random or pseudo-random manner one or more of the MA time domain resource, the MA frequency domain resource, and MA signature for a subsequent UL NOMA retransmission of the data; when operating in synchronous retransmission mode, if no acknowledgement

(ACK) has been received for a UL NOMA retransmission during a specified timeout period, select an MA physical resource and MA signature for a subsequent UL NOMA retransmission of the data as a function of the MA physical resource and MA signature used for the prior UL NOMA retransmission to synchronize the subsequent UL NOMA retransmission with the prior UL NOMA retransmission; and, continue to select MA physical resources and MA signatures for subsequent UL NOMA retransmissions when no ACK has been received for the prior UL NOMA retransmission up until a specified maximum number of retransmissions.

19. The apparatus of claim 17 or 18 wherein either synchronous retransmission mode or asynchronous retransmission mode is configured as part of the MA physical resource pool configuration by the BS in a semi-static manner.

20, The apparatus of claim 17 or 18 wherein the synchronous or asynchronous retransmission mode is enabled by broadcast message from the BS.

21. The apparatus of claim 17 or 18 wherein the processing circuitry is to: select an MA physical resource and MA signature for an UL NOMA preamble and/or control channel transmission occurs before the UL NOMA data transmission; and, wherein the preamble and/or control channel transmission indicates the MA physical resource used by the UL NOMA data transmission.

22, The apparatus of claim 21 wherein the processing circuitry is to operate in a synchronous retransmission mode with respect to the preamble and/or control channel transmission and operate in an asynchronous retransmission mode with respect to the data transmission.

23. A computer-readable storage medium comprises instructions to cause processing circuitry of a user equipment (UE), upon execution of the instructions by the processing circuitry, to: select a multiple access (MA) physical resource from an MA physical resource pool for an initial grant-free uplink (UL) non-orthogonal multiple access (NOMA) transmission of data to a base station (BS), wherein the MA physical resource is a time-frequency resource of a multi-carrier or single-carrier modulation scheme that includes a time domain resource corresponding to one or more time periods and a frequency domain resource corresponding to one or more subcarriers; select an MA signature for the initial grant-free UL NOMA transmission that corresponds to a transmission pattern to distinguish the UL NOMA transmission from an UL NOMA transmission from another UE using the same selected MA physical resource; store data for retrieval and inclusion in the initial grant-free UL NO A transmission; and, select a physical resource for transmission of a preamble and/or control channel that occurs before transmission of a data channel in initial grant-free UL NOMA transmission.

24. The storage medium of 23 wherein the preamble and/or control channel transmission indicates the MA physical resource used by the UL NOMA data channel.

25. The storage medium of claim 23 or 24 further comprising instructions to, after transmission of the preamble and/or control channel, await feedback from the BS before encoding the UL NOMA data channel.