CN112352407A - Peak-to-average power ratio (PAPR) reduction in reference signals - Google Patents

Abstract

Techniques for a next generation node b (gnb) operable to generate downlink reference signals with reduced peak-to-average power ratio (PAPR) are disclosed. The gNB may map complex pseudo-noise (PN) sequence symbols to one or more Code Division Multiplexing (CDM) groups. The gNB may perform CDM group-specific linear or non-linear operations on complex PN sequence symbols mapped to the one or more CDM groups on each of the one or more CDM groups to generate a downlink reference signal with reduced PAPR. The gmb may encode a downlink reference signal with a reduced PAPR at the gmb for transmission to a User Equipment (UE).

Description

Peak-to-average power ratio (PAPR) reduction in reference signals

Background

A wireless system typically includes a plurality of User Equipment (UE) devices communicatively coupled to one or more Base Stations (BSs). The one or more BSs may be Long Term Evolution (LTE) evolved node BS (enbs) or new radio interface (NR) next generation node BS (gnbs) capable of being communicatively coupled to the one or more UEs through a third generation partnership project (3GPP) network.

The next generation wireless communication system is expected to be a unified network/system with the goal of meeting very different and sometimes conflicting performance dimensions and services. New air interface access technologies (RATs) are expected to support a wide range of use cases including enhanced mobile broadband (eMBB), large-scale machine type communication (mtc), mission critical machine type communication (mtc), and similar service types operating in frequency ranges up to 100 GHz.

Drawings

The features and advantages of the present disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating by way of example the features of the present disclosure; and, in the drawings:

fig. 1 illustrates a block diagram of a third generation partnership project (3GPP) new air interface (NR) release 15 frame structure, according to an example;

fig. 2 illustrates a new air interface (NR) release 15 demodulation reference signal (DM-RS) type, according to an example;

fig. 3 illustrates PAPR degradation in release 15 single symbol, type 1 and type 2 DMRSs, according to an example;

fig. 4 illustrates PAPR improvement in a type 1DMRS, according to an example;

fig. 5 illustrates PAPR improvement in a type 1DMRS, according to an example;

fig. 6 illustrates Code Division Multiplexing (CDM) group-specific c based on an example_initPseudo-random number (PN) sequence generation and mapping;

fig. 7 depicts functionality of a user equipment operable to generate a demodulation reference signal (DM-RS) with reduced peak-to-average power ratio (PAPR), according to an example;

fig. 8 depicts functionality of a next generation node b (gnb) operable to generate downlink reference signals with reduced peak-to-average power ratio (PAPR), according to an example;

fig. 9 depicts functionality of generating demodulation reference signals (DM-RSs) with reduced peak-to-average power ratio (PAPR), according to an example;

fig. 10 illustrates an architecture of a wireless network according to an example;

fig. 11 illustrates a diagram of a wireless device (e.g., UE), according to an example;

fig. 12 illustrates an interface of a baseband circuit according to an example; and is

Fig. 13 illustrates a diagram of a wireless device (e.g., UE) according to an example.

Reference will now be made to the exemplary embodiments illustrated, and specific language will be used herein to describe the same. It will nevertheless be understood that no limitation of the scope of the technology is thereby intended.

Detailed Description

Before the present technology is disclosed and described, it is to be understood that this technology is not limited to the particular structures, process actions, or materials disclosed herein, but extends to equivalents thereof as would be recognized by those ordinarily skilled in the relevant arts. It is also to be understood that the terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting. Like reference symbols in the various drawings indicate like elements. The numerals provided in the flowcharts and processes are provided for clarity in illustrating the acts and operations and do not necessarily indicate a particular order or sequence.

Definition of

As used herein, the term "User Equipment (UE)" refers to a computing device capable of wireless digital communication, such as a smartphone, a tablet computing device, a laptop computer, such as an iPod

Such as multimedia devices or other types of computing devices that provide text or voice communications. The term "User Equipment (UE)" may also be referred to as a "mobile device," wireless device, "or" wireless mobile device.

As used herein, the term "Base Station (BS)" includes "Base Transceiver Station (BTS)", "node B", "evolved node B (eNodeB or eNB)", "new base radio interface station (NR BS)", and/or "next generation node B (gdnodeb or gNB)", and refers to a device or configuration node of a mobile phone network that wirelessly communicates with a UE.

As used herein, the terms "cellular telephone network," "4G cellular," "Long Term Evolution (LTE)," "5G cellular," and/or "new air interface (NR)" refer to wireless broadband technologies developed by the third generation partnership project (3 GPP).

Example embodiments

An initial overview of technical embodiments is provided below, followed by a more detailed description of specific technical embodiments. This initial summary is intended to assist the reader in understanding the present technology more quickly, and is not intended to identify key features or essential features of the present technology, nor is it intended to limit the scope of the claimed subject matter.

Fig. 1 provides an example of a 3GPP NR release 15 frame structure. In particular, fig. 1 illustrates a downlink radio frame structure. In this example, a radio frame 100 for transmitting a signal of data may be configured to have a duration T of 10 milliseconds (ms)_f. Each radio frame may be partitioned or divided into ten subframes 110i, each 1ms long. Each subframe may be further subdivided into one or more slots 120a, 120i, and 120x, each slot having a duration T of 1/μms_slotWhere for 15kHz the subcarrier spacing μ 1, for 30kHz μ 2, for 60kHz μ 4, for 120kHz μ 8 and for 240kHz μ 16. Each slot may include a Physical Downlink Control Channel (PDCCH) and/or a Physical Downlink Shared Channel (PDSCH).

Each slot of a Component Carrier (CC) used by the node and the wireless device may include a plurality of Resource Blocks (RBs) 130a, 130b, 130i, 130m, and 130n based on the CC frequency bandwidth. The CC may have a carrier frequency with a bandwidth. Each slot of the CC may include Downlink Control Information (DCI) present in the PDCCH. The PDCCH is transmitted in a control channel resource set (CORESET), which may include one, two, or three Orthogonal Frequency Division Multiplexing (OFDM) symbols and a plurality of RBs.

Each RB (physical RB or PRB) may include 12 subcarriers (on a frequency axis) and 14 Orthogonal Frequency Division Multiplexing (OFDM) symbols (on a time axis) per slot. If a short or normal Cyclic Prefix (CP) is employed, the RB may use 14 OFDM symbols. If an extended cyclic prefix is used, the RB may use 12 OFDM symbols. A resource block may be mapped to 168 Resource Elements (REs) using a short or normal cyclic prefix, or a resource block may be mapped to 144 REs using an extended cyclic prefix (not shown). The REs may be a unit of one OFDM symbol 142 by one subcarrier (i.e., 15kHz, 30kHz, 60kHz, 120kHz, and 240kHz) 146.

Each RE 140i can transmit two bits 150a and 150b of information in case of Quadrature Phase Shift Keying (QPSK) modulation. Other types of modulation, such as 16 Quadrature Amplitude Modulation (QAM) or 64QAM, may be used to transmit a larger number of bits in each RE, or Binary Phase Shift Keying (BPSK) modulation may be used to transmit a smaller number of bits (a single bit) in each RE. RBs may be configured for downlink transmissions from the eNodeB to the UE or for uplink transmissions from the UE to the eNodeB.

This example of a 3GPP NR release 15 frame structure provides an example of a way, or transmission mode, to transmit data. This example is not intended to be limiting. Many release 15 features will evolve and change in the 5G frame structures included in 3GPP LTE release 15, MulteFire release 1.1, and beyond. In such systems, design constraints may coexist with multiple sets of 5G parameters in the same carrier due to the coexistence of different network services, such as eMBB (enhanced mobile broadband), mtc (massive machine type communication or massive IoT), and URLLC (ultra-reliable low latency communication or critical communication). The carrier in a 5G system may be higher or lower than 6 GHz. In one embodiment, each network service may have a different set of parameters (numerology).

In one configuration, in release 15NR, the demodulation reference signals (DMRS) are user specific reference signals that may be used for channel estimation for Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH) data demodulation. In release 15NR, in the case where CP-OFDM waveforms are used for PDSCH and PUSCH, DM-RS is generated using a length 31Gold sequence similar to LTE. The Zadoff-chu (zc) sequence may be used for Discrete Fourier Transform (DFT) -spread Orthogonal Frequency Division Multiplexing (OFDM) (i.e., when transform precoding is enabled) waveform for PUSCH. There may be two different DM-RS configurations, type 1 and type 2. A type 1DM-RS has 2 Code Division Multiplexed (CDM) port groups, where each group occupies 6 orthogonal frequency Resource Elements (REs) within a Physical Resource Block (PRB) on a single OFDM symbol. Type 1 single symbol DM-RS may support up to 4 orthogonal DMRS ports, with 2DM-RS ports multiplexed with a frequency domain orthogonal cover code (FD-OCC) within each CDM group. Type 2DM-RS has 3 CDM port groups, where each group occupies 4 orthogonal REs within a PRB on a single OFDM symbol. Type 2 single symbol DM-RS may support up to 6 orthogonal DMRS ports, with each CDM group having 2DM-RS ports using FD-OCC multiplexing. Further, both type 1 and type 2DM-RS may occupy two OFDM symbols, where ports are multiplexed using Time Domain (TD) OCC in addition to FD-OCC. The two symbol type 1DM-RS may support up to 8 ports with 4 ports in each CDM group. The two symbol type 2DM-RS may support up to 12 orthogonal ports with 4 ports in each CDM group.

In one example, length 31Gold sequences are mapped to DM-RS ports such that the sequence values are the same for all DMRS ports (before applying precoders and OCC), which may result in an increase in peak-to-average power ratio (PAPR) of the time domain OFDM signal for some specific configuration cases, e.g., when only port 0 and port 2 are configured for type 1 and type 2DMRS together and an off-diagonal precoder is used, or when ports 0-3 or higher are configured for type 1 and type 2DMRS and an off-diagonal precoder is used.

In one example, similar issues exist for Channel State Information (CSI) reference signals, and the solutions described below may be similarly applied to CSI-RS.

In one configuration, NR Multiple Input Multiple Output (MIMO) low PAPR reference signal designs are described herein. Low PAPR reference signal designs may achieve PAPR reduction in the reference signal. PAPR reduction may be achieved by randomizing time domain sequences corresponding to different ports or to ports belonging to different CDM groups using a mathematical operation. For example, three different techniques for randomization may be used as follows: (1) operate with CDM groups of specific sequences, e.g., complex conjugation; (2) using a CDM group specific time domain cyclic shift; or (3) generate a unique random sequence for each CDM group using a CDM group-specific initialization value.

Fig. 2 illustrates an example of a new air interface (NR) release 15 demodulation reference signal (DM-RS) type. In NR version 15, two different DM-RS types, type 1 and type 2DM-RS, are used. For the single symbol case, the type 1DMRS may use a comb-2 structure with 2 CDM groups and a length of 2FD-OCC in each pair of alternating REs in each CDM group. The type 2DMRS may use a comb-3 structure having 3 CDM groups and a length of 2FD-OCC in each pair of alternating REs in each CDM group. The length 2FD-OCC is given by [11,1-1 ]. For the case of CP-OFDM waveforms, both type 1 and type 2DM-RS may use complex Quadrature Phase Shift Keying (QPSK) sequences r (n) generated as follows:

where c (i) is a pseudo-random length 31Gold sequence initialized by:

in one example, the generated sequence may then be mapped to a physical resource as follows:

in one example, the values of the different parameters k ', l', n, Δ are specified in 3GPP TS 38.211v15.1.0, NR physical channel and modulation (release 15), Tables 6.4.1.1.3-1 and 7.4.1.1.2-1 for uplink and downlink, respectively. After sequence mapping, the DM-RS is precoded and transmitted from the physical antenna ports. Note that the DM-RS port is equivalent to the MIMO layer, not a physical antenna port. The precoding is performed as follows:

in one example, this precoder is applied per subcarrier for all subcarriers within the same PRG. The dimension of the precoder matrix is [ W ]]_ρ×υI.e. the number of antenna ports multiplied by the number of MIMO layers. The mapping of MIMO layers or DMRS antenna ports follows the comb/subcarrier structure defined by each DMRS type. For example, consider the case of a single sign DM-RS type 2 with 6 DM-RS ports, i.e., v 6. In this case, for the first subcarrier in the PRB, the precoder will only be applied to ports 0,1, since these are the only ports in the 1 st CDM group. The remaining ports are replaced with zeros and the precoding will be as follows:

in one example, for antenna port 0, precoding may be expressed in terms of the first row of the precoder matrix as:

based on NR version 15 sequence mapping, the mapping r (2n + k') is independent of CDM groups, i.e., the ports within each CDM group share the same DMRS sequence values. Due to this mapping structure, when two ports from different CDM groups have the same FD-OCC value, they also have adjacent subcarriers

The same value of (a). For example, having the features of respectivelyThe case of scheduled type 1DMRS for ports 0, 2 of CDM groups 1 and 2 with the same FD-OCC value may result in the following case:

for this example, consider a precoding matrix such that W_n,0,W _n,21. After precoding considers all subcarriers within a PRB, the DMRS sequence is repeated in the frequency domain as follows:

similarly for DM-RS type 2, the repetition of the sequence value for the case when ports 0, 2 are scheduled has the following form:

in one example, this repetition of DMRS sequences in the frequency domain may result in coherent combining of signals in the time domain after Inverse Fast Fourier Transform (IFFT) for OFDM symbol generation, resulting in degradation of PAPR compared to CP-OFDM with random QPSK in each subcarrier. This problem may occur for most off-diagonal precoders. Similar problems are likely to occur in the case of the type 2 DMRS. Furthermore, in the case when all possible layers are scheduled for both type 1 and type 2 DMRSs, this degradation still exists for some off-diagonal precoders and antenna ports.

Fig. 3 illustrates an example of PAPR degradation in release 15 single symbol type 1 and type 2 DMRSs. A plot of the Complementary Cumulative Distribution Function (CCDF) per antenna port PAPR of release 15DMRS is shown for all possible Precoding Matrix Indications (PMIs) for each rank. For the full load case, PAPR over all antenna ports and precoders degrades for release 15DMRS design due to the fact that the same sequence values are mapped to multiple CDM groups. This problem is common to both DL and UL operations. However, the case of UL with type 2DMRS is limited to rank 4 operation, and thus, the problem of both type 1 and type 2 is the same, since all 3 CDM groups are never scheduled simultaneously from the UE perspective.

In one configuration, techniques are described that address the high PAPR problem of the release 15NR DM-RS sequence mapping.

In one example, conjugate sequences may be used for type 1 and type 2 DM-RS. In this example, for type 1 and 2DM-RS, the sequence mapping of release 15NR is used to map the complex QPSK PN sequence to ports within the first CDM group in the frequency domain. For ports within the second CDM group, the complex conjugate of the sequence value in the first comb may be used. The use of a complex conjugate sequence in the frequency domain results in a time-reversed cyclic shift sequence in the time domain corresponding to the second CDM group. This results in a reduction in PAPR of the time domain OFDM symbol.

An example of this mapping for type 1DM-RS is as follows:

k 4n +2 k' + Δ for configuration type 1

Where r (2n + k ') denotes the complex conjugate of the sequence value r (2n + k').

Fig. 4 illustrates an example of PAPR improvement in a type 1 DMRS. PAPR improvement in type 1DMRS is achieved using the aforementioned technique of using conjugate sequences for type 1 DM-RS.

In one example, for type 2DM-RS, the following may be used: release 15NR DM-RS in CDM group 1, conjugation of sequence values of CDM group 1 mapped to ports in CDM group 2, and application to CDM groupSequence value of 1 and e mapped to ports in CDM group 3^-jπk/2The complex phase shift of (a). The phase shift of the sequence values in CDM group 3 results in a time domain cyclic shift of N/4, where N is the IFFT size. This reduces the PAPR of the overall OFDM signal.

An example of this mapping for type 2DM-RS is as follows:

k 6n + k' + Δ for configuration type 2

Fig. 5 illustrates an example of PAPR improvement in type 2 DMRS. PAPR improvement in type 2DMRS is achieved using the aforementioned technique using a conjugate sequence for type 2 DM-RS.

In one example, this technique may reduce PAPR for all off-diagonal precoders that may be applied to DM-RS. The technique applies equally to downlink and uplink DMRS.

In one example, a phase shift only scheme may be used, whereby a CDM group specific phase shift is applied to all sequence values in CDM group 2 for type 1DMRS and to all sequence values in CDM groups 2 and 3 for type 2 DMRS.

For example, for type 1DM-RS, the sequence value r (2n + k') may be mapped to a first CDM group, while for a second CDM group, the CDM group is phase shifted e specifically^-jπk/2Can be applied to the sequence value, i.e. the sequence value e^-jπk/2r (2n + k') may be mapped to ports in CDM group 2. This will reduce carriagePAPR of OFDM symbol of DM-RS. Phase shift fetch set [ 1-j-1 j]A value of (1).

In another example, for type 2DM-RS, a sequence value r (2n + k') may be mapped to the first CDM group. For the second CDM group, the CDM group is phase-shifted by e^-jπk/2Can be applied to the sequence value, i.e. the sequence value e^-jπk/2r (2n + k') may be mapped to ports in CDM group 2. This will reduce the PAPR of the OFDM symbol. For the third CDM group, phase shift e^-jπk/4Sequence value that can be applied to CDM group 1, i.e., sequence value e^-jπk/4r (2n + k') may be mapped to ports in CDM group 3. This reduces the PAPR of OFDM symbols carrying DM-RS.

In another example, the phase shift e applied to the sequence value in CDM group 2^-jπk/6And phase shift e applied to CDM group 3^-jπk/12The PAPR of the OFDM symbol carrying the DM-RS is also reduced.

In one example, CDM group-specific phase shifts may be applied to sequence values mapped to different CDM groups for CSI-RS to reduce PAPR of OFDM symbols carrying CSI-RS.

For example, for CSI-RS, sequence mapping from release 15NR may be used for the first CDM group. For the remaining CDM group(s) is (are),

a form of CDM group-specific phase shift may be applied to the CDM group N mapped thereto_cdmE.g., a sequence of {2, 3. This may reduce PAPR of OFDM symbols carrying CSI-RS.

In one example, by making the PN sequence initialization CDM group specific, a different sequence may be generated for each CDM group for both type 1 and type 2 DM-RS.

As an example, to generate a CDM group-specific PN sequence, the following initialization may be used for a length 31Gold sequence:

wherein N is_cdmIs the total number of CDM groups. For DM-RS type 1, N _cdm2 and for DM-RS type 2, N_cdm＝3。n_CDMIDE {0,1,2} is the ID associated with the CDM group for which the sequence is generated. Thus, c is proposed_initIs CDM group specific. Use of this c_initThe generated sequence value can be represented by r_nCDMID(n) represents, which may then follow r_nCDMID(2n + k') is mapped to CDM group n_CDMID。

FIG. 6 illustrates CDM group-based specific c_initExamples of pseudo-random (PN) sequence generation and mapping. For CDM group-based specific c_initTwo sequences may be used for DMRS type 1 and up to 3 sequences may be used for DMRS type 2.

In one example, for DMRS type 2, the following initialization of Gold sequences may be used for PDSCH and PUSCH based on CP-OFDM waveforms:

in another example, n_CDMIDΔ, where Δ is specified in 3GPP TS 38.211v15.1.0, NR physical channel and modulation (release 15).

The above examples may also be extended to the case of a two-symbol DMRS and for any additional DMRSs that may be configurable in the later part of the slot. Hereinafter, CDM group specific c is described_initAdditional techniques of generation.

In one example, for DMRS type 1, original version 15c_initMay be used for the first CDM group ( port 0,1 for one-symbol DMRS, port 0,1, 4, 5 for 2-symbol DMRS), that is,

in this case, DCI 0_1 is used for UL and DCI 1_1 is used for DL, the scrambling ID n may be notified_SCIDE {0,1}, wherein the Cyclic Redundancy Check (CRC) is determined by a cell radio network temporary identifier (C-RNTI), a configuration scheduling cell radio network temporary identifier (CS-RNTI), or a modulation coding scheme cell radioAn electrical network temporary identifier (MCS-C-RNTI). For the second CDM group ( ports 2,3 for one-symbol DMRS and ports 2,3, 6, 7 for two-symbol DMRS), the following c may be used_init：

Wherein the content of the first and second substances,

in one example, for multiple Transmit Receive Point (TRP) operation or dynamic TRP handover, a UE may be configured with n for one TRP _SCID0 and can be configured with n for another TRP _SCID1. This solution does not incur additional RRC impact compared to release 15 NR.

In one example, for the case of a default DMRS configuration for DCI format 1_0 in DL and DCI format 0_0 in UL or a DMRS configuration using a DCI format with CRC scrambled by an RNTI other than C-RNTI, CS-RNTI, or MCS-C-RNTI, the UE may use the same initialization as in legacy release 15NR, with a default value of n_SCID＝0。

In one example, for DMRS type 1, based on n indicated by DCI_SCIDThe following c may be used for each CDM group_initAny two of the values:

in one example, for DMRS type 2, based on n indicated by DCI_SCIDThe following c may be used for each CDM group_initAny three of the values:

in one example, when a UE is configured with n by DCI format 1_1 of DL and DCI format 0_1 of UL_SCIDE {0,1}, where CRC is scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI, the following C can be used in the three CDM groups_init：

Wherein

Can be made of any one of the followingGive out

Wherein, (.)^cIndicating bit reversal

Wherein, (.)^(s)Indication of N_IDCyclically shifted versions of s bits

In one example, for multiple TRP operation or dynamic TRP handover, a UE may be configured with n for one TRP _SCID0 and may be configured with n for another TRP _SCID1. This solution does not incur additional RRC impact compared to release 15 NR.

In one example, a UE may be configured (using Radio Resource Control (RRC) signaling) by higher layers in two sets, each set containing two 16-bit N_IDThe value is obtained. Set 1 contains values

And set 2 contains values

In the case of using only CDM groups 1 and 2, the following initialization values may be used for the two CDM groups:

wherein the content of the first and second substances,

and

indicating an ID from set 1

In this case, IDn is scrambled_SCIDE {0,1} may be notified using DCI 0_1 of UL or DCI 1_1 of DL, where CRC is scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI. In case of using the third CDM group, n is used_SCIDA configuration value of e {0,1} and N from set 2_IDThe values may be initialized in the third CDM group using:

in one example, for multiple TRP operation or dynamic TRP handover, a UE may be configured with n for one TRP _SCID0 and may be configured with n for another TRP _SCID1. This solution will maintain maximum backward compatibility with the version 15 NR.

In one example, the sequence for one of the CDM groups of DM-RS type 2 may also be obtained using an exclusive or operation of two sequences generated by:

and

in one example, version 15c is used_initOr c newly proposed for version 16_initThe selection of (c) may be configured by higher layer RRC parameters to the UE.

In one configuration, a technique is described for achieving PAPR reduction of downlink and uplink reference signals by performing CDM group-specific nonlinear operations on complex PN sequence symbols mapped to each CDM group. The reference signals may be DM-RS and/or CSI-RS.

In one example, a CDM group-specific shift may be applied to sequence values mapped to ports in CDM group 2 in type 1 DMRS. In another example, for type 2DM-RS, a CDM group-specific shift may be applied to sequence values mapped to ports in CDM group 2, and a different CDM group-specific phase shift may be applied to ports in CDM group 3. In another example, different frequency-domain CDM group-specific phase shifts may be applied to ports in different CDM groups for CSI-RS.

In one configuration, a technique for PAPR reduction in DMRS is described in which a CDM group-specific initialization value is used to generate a CDM group-specific unique PN sequence. In one example, CDM group-specific PN sequences may be used for both DMRS type 1 and type 2 to map sequence values to ports within each CDM group. In another example, CDM group-specific PN sequence initialization values for type 1 and type 2 DMRSs may be derived from binary scrambling IDs (n)_SCIDA DCI indication value of e {0,1}) is implicitly derived.

In one example, the new sequence may be used only when DCI formats 0_1 and 1_1 are used in which the CRC is scrambled by C-RNTI, CS-RNTI, and MCS-C-RNTI. In another example, for DMRS type 2, RRC may configure two sets, each containing two 16-bit N_ID. In another example, for CDM groups 0 and 1, two N from the first set may be used_IDAnd for CDM group 2, two N from the second set may be used_IDOne of them. In another example, N is configured from the second RRC for CDM group 2 pair_IDN of the set_IDMay be selected by n of the DL where the CRC is scrambled by C-RNTI, CS-RNTI or MCS-C-RNTI_SCIDBit DCI format 1_1 or n of UL_SCIDBit DCI format 0_1 to indicate dynamically. In another example, the selection to use the new techniques described herein or to use the release 15 technique may be configurable for the UE and configurable by RRC parameters.

Another example provides functionality 700 of a User Equipment (UE) operable to generate a demodulation reference signal (DM-RS) with reduced peak-to-average power ratio (PAPR), as shown in fig. 7. The UE may include one or more processors configured to map complex pseudo-noise (PN) sequence symbols to one or more Code Division Multiplexing (CDM) groups at the UE, as shown in block 710. The UE may include one or more processors configured to perform, on each CDM group of the one or more CDM groups, CDM group-specific linear or non-linear operations on complex PN sequence symbols mapped to the one or more CDM groups to generate DM-RSs having reduced PAPR, as shown in block 720. The UE may include one or more processors configured to encode, at the UE, the DM-RS with reduced PAPR for transmission to a next generation node b (gnb), as shown in block 730. Further, the UE may include a memory interface configured to transmit the mapped complex PN sequence symbols to a memory.

Another example provides functionality 800 of a next generation node b (gnb) operable to generate downlink reference signals with reduced peak-to-average power ratio (PAPR), as shown in fig. 8. The gNB may include one or more processors configured to map complex pseudo-noise (PN) sequence symbols to one or more Code Division Multiplexing (CDM) groups at the gNB, as shown in block 810. The gNB may include one or more processors configured to perform a CDM group-specific linear or non-linear operation on complex PN sequence symbols mapped to the one or more CDM groups on each of the one or more CDM groups to generate a downlink reference signal having a reduced PAPR, as shown in block 820. The gNB may include one or more processors configured to generate a downlink reference signal with a reduced PAPR at the gNB for transmission to a User Equipment (UE), as shown in block 830. Further, the gNB may include a memory interface configured to retrieve the mapped complex PN sequence symbols from memory.

Another example provides at least one machine readable storage medium having instructions 900 stored thereon for generating a demodulation reference signal (DM-RS) with reduced peak-to-average power ratio (PAPR), as shown in fig. 6. The instructions may be executed on a machine, where the instructions are included on at least one computer-readable medium or at least one non-transitory machine-readable storage medium. The instructions, when executed by one or more processors of a User Equipment (UE), perform: one or more Code Division Multiplexing (CDM) group-specific initialization values are identified at the UE, as shown in block 910. The instructions, when executed by the one or more processors, perform: one or more CDM group-specific initialization values are used at the UE to generate a CDM group-specific unique pseudo-noise (PN) sequence, as shown in block 920. The instructions, when executed by the one or more processors, perform: the DM-RS with reduced PAPR is generated at the UE using a CDM group-specific unique PN sequence, as shown in block 930. The instructions, when executed by the one or more processors, perform: the DM-RS with reduced PAPR is encoded at the UE for transmission to a next generation node b (gnb), as shown in block 940.

Fig. 10 illustrates an architecture of a system 1000 of networks, according to some embodiments. System 1000 is shown to include User Equipment (UE)1001 and UE 1002. The UEs 1001 and 1002 are illustrated as smart phones (e.g., handheld touch screen mobile computing devices connectable to one or more cellular networks), but may also include any mobile or non-mobile computing device, such as a Personal Data Assistant (PDA), pager, laptop computer, desktop computer, wireless handset, or any computing device that includes a wireless communication interface.

In some embodiments, any of UEs 1001 and 1002 may include an internet of things (IoT) UE, which may include a network access layer designed for low power IoT applications that use short-term UE connections. IoT UEs may use technologies such as machine-to-machine (M2M) or Machine Type Communication (MTC) to exchange data with MTC servers or devices via Public Land Mobile Networks (PLMNs), proximity-based services (ProSe) or device-to-device (D2D) communication, sensor networks, or IoT networks. The M2M or MTC data exchange may be a machine initiated data exchange. IoT network descriptions use short-term connections to interconnect IoT UEs, which may include uniquely identifiable embedded computing devices (within the internet infrastructure). The IoT UE may execute background applications (e.g., keep-alive messages, status updates, etc.) to facilitate connection of the IoT network.

UEs 1001 and 1002 may be configured to connect with (e.g., communicatively couple with) a Radio Access Network (RAN)1010 — RAN 1010 may be, for example, an evolved Universal Mobile Telecommunications System (UMTS) terrestrial radio access network (E-UTRAN), a next generation RAN (NextGen RAN, NG RAN), or some other type of RAN. UEs 1001 and 1002 use connections 1003 and 1004, respectively, each of which includes a physical communication interface or layer (discussed in more detail below); in this example, connections 1003 and 1004 are shown as air interfaces to enable communicative coupling and may conform to a cellular communication protocol, such as a global system for mobile communications (GSM) protocol, a Code Division Multiple Access (CDMA) network protocol, a push-to-talk (PTT) protocol, a cellular PTT (poc) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a fifth generation (5G) protocol, a new air interface (NR) protocol, and so forth.

In this embodiment, the UEs 1001 and 1002 may also exchange communication data directly via the ProSe interface 1005. The ProSe interface 1005 may alternatively be referred to as a sidelink interface that includes one or more logical channels, including but not limited to a Physical Sidelink Control Channel (PSCCH), a physical sidelink shared channel (PSCCH), a Physical Sidelink Discovery Channel (PSDCH), and a Physical Sidelink Broadcast Channel (PSBCH).

UE 1002 is shown configured to access an Access Point (AP)1006 via a connection 1007. Connection 1007 may comprise a logical wireless connection, such as a connection conforming to any IEEE 1102.15 protocol, where AP 1006 will include wireless fidelity (r: (r))

) A router. In this example, the AP 1006 is shown connected to the internet, not to the core network of the wireless system (described in more detail below).

RAN 1010 may include one or more access nodes that enable connections 1003 and 1004. These Access Nodes (ANs) may be referred to as Base Stations (BSs), nodebs, evolved nodebs (enbs), next generation nodebs (gnbs), RAN nodes, etc., and may include ground stations (e.g., ground access points) or satellite stations that provide coverage within a certain geographic area (e.g., a cell). The RAN 1010 may include one or more RAN nodes, such as a macro RAN node 1011, for providing a macro cell, and one or more RAN nodes, such as a Low Power (LP) RAN node 1012, for providing a femto cell or a pico cell (e.g., a cell with less coverage area, less user capacity, or higher bandwidth than a macro cell).

Either of RAN nodes 1011 and 1012 may terminate the air interface protocol and may be the first point of contact for UEs 1001 and 1002. In some embodiments, any of the RAN nodes 1011 and 1012 may perform various logical functions for the RAN 1010, including, but not limited to, Radio Network Controller (RNC) functions such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

In accordance with some embodiments, UEs 1001 and 1002 may be configured to communicate with each other or with any of RAN nodes 1011 and 1012 using Orthogonal Frequency Division Multiplexed (OFDM) communication signals over a multicarrier communication channel in accordance with various communication techniques, such as, but not limited to, Orthogonal Frequency Division Multiple Access (OFDMA) communication techniques (e.g., for downlink communications) or single carrier frequency division multiple access (SC-FDMA) communication techniques (e.g., for uplink and ProSe or sidelink communications), although the scope of the embodiments is not limited in this respect. The OFDM signal may include a plurality of orthogonal subcarriers.

In some embodiments, the downlink resource grid may be used for downlink transmissions from either of RAN nodes 1011 and 1012 to UEs 1001 and 1002, while uplink transmissions may use similar techniques. The grid may be a time-frequency grid, referred to as a resource grid or time-frequency resource grid, which is the physical resource in the downlink in each slot. This time-frequency plane representation is a common practice of OFDM systems, which makes it intuitive for radio resource allocation. Each column and first row of the resource grid corresponds to one OFDM symbol and one OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to one slot in the radio frame. The smallest time-frequency unit in the resource grid is denoted as a resource element. Each resource grid comprises several resource blocks, which describe the mapping of a specific physical channel to resource elements. Each resource block comprises a set of resource elements; in the frequency domain, this may represent the minimum number of resources that can currently be allocated. There are several different physical downlink channels that use this resource block transport.

A Physical Downlink Shared Channel (PDSCH) may carry user data and higher layer signaling to UEs 1001 and 1002. A Physical Downlink Control Channel (PDCCH) may carry information about transport formats and resource allocations related to the PDSCH channel, and so on. It may also inform the UEs 1001 and 1002 about transport format, resource allocation and H-ARQ (hybrid automatic repeat request) information related to the uplink shared channel. In general, downlink scheduling (assigning control and shared channel resource blocks to UEs 1002 within a cell) may be performed at any of RAN nodes 1011 and 1012 based on channel quality information fed back from any of UEs 1001 and 1002. The downlink resource assignment information may be sent on the PDCCH used for (e.g., assigned to) each of UEs 1001 and 1002.

The PDCCH may use Control Channel Elements (CCEs) to carry control information. The PDCCH complex-valued symbols may first be organized into quadruplets before being mapped to resource elements, which may then be permuted using sub-block interleavers for rate matching. Each PDCCH may be transmitted using one or more of these CCEs, where each CCE may correspond to nine sets of four physical resource elements called Resource Element Groups (REGs). Four Quadrature Phase Shift Keying (QPSK) symbols may be mapped for each REG. Depending on the size of Downlink Control Information (DCI) and channel conditions, the PDCCH may be transmitted using one or more CCEs. There may be four or more different PDCCH formats defined in LTE, with different numbers of CCEs (e.g., aggregation level L ═ 1,2, 4, or 11).

Some embodiments may use the concept of resource allocation for control channel information, which is an extension of the above-described concept. For example, some embodiments may use an Enhanced Physical Downlink Control Channel (EPDCCH) that uses PDSCH resources for control information transmission. The EPDCCH may be transmitted using one or more Enhanced Control Channel Elements (ECCEs). Similar to the above, each ECCE may correspond to nine sets of four physical resource elements called Enhanced Resource Element Groups (EREGs). ECCE may have other numbers of EREGs in some cases.

RAN 1010 is shown communicatively coupled to a Core Network (CN)1020 — via S1 interface 1013. In embodiments, CN 1020 may be an Evolved Packet Core (EPC) network, a next generation packet core (NPC) network, or some other type of CN. In this embodiment, the S1 interface 1013 is split into two parts: an S1-U interface 1014 that carries traffic data between RAN nodes 1011 and 1012 and a serving gateway (S-GW)1022, and an S1 Mobility Management Entity (MME) interface 1015, which is a signaling interface between the RAN nodes 1011 and 1012 and the MME 1021.

In this embodiment, CN 1020 includes MME 1021, S-GW 1022, Packet Data Network (PDN) gateway (P-GW)1023, and Home Subscriber Server (HSS) 1024. The MME 1021 may be similar in function to the control plane of a conventional serving General Packet Radio Service (GPRS) support node (SGSN). The MME 1021 may manage mobility aspects in access such as gateway selection and tracking area list management. HSS 1024 may include a database for network users, including subscription-related information to support processing of communication sessions by network entities. CN 1020 may include one or several HSS 1024, depending on the number of mobile subscribers, the capacity of the devices, the organization of the network, etc. For example, HSS 1024 may provide support for routing/roaming, authentication, authorization, naming/addressing resolution, location compliance, and so on.

The S-GW 1022 may terminate the S1 interface 1013 toward the RAN 1010 and route data packets between the RAN 1010 and the CN 1020. In addition, the S-GW 1022 may be a local mobility anchor for inter-RAN node handovers and may also provide an anchor for inter-3 GPP mobility. Other responsibilities may include lawful interception, charging, and some policy enforcement.

The P-GW 1023 may terminate the SGi interface towards the PDN. P-GW 1023 may route data packets between EPC network 1023 and an external network, such as a network including application server 1030 (otherwise referred to as an Application Function (AF)), via Internet Protocol (IP) interface 1025. In general, the application server 1030 may be an element that provides applications that use IP bearer resources with the core network (e.g., UMTS Packet Service (PS) domain, LTE PS data services, etc.). In this embodiment, P-GW 1023 is shown communicatively coupled to application server 1030 via IP communication interface 1025. Application server 1030 may also be configured to support one or more communication services (e.g., voice over internet protocol (VoIP) sessions, PTT sessions, group communication sessions, social networking services, etc.) for UEs 1001 and 1002 via CN 1020.

P-GW 1023 may also be a node for policy enforcement and charging data collection. A policy and charging enforcement function (PCRF)1026 is a policy and charging control element of the CN 1020. In a non-roaming scenario, there may be a single PCRF in a Home Public Land Mobile Network (HPLMN) that is associated with an internet protocol connectivity access network (IP-CAN) session for a UE. In a roaming scenario with local breakout of traffic, there may be two PCRFs associated with the IP-CAN session of the UE: a home PCRF (H-PCRF) within the HPLMN and a visited PCRF (V-PCRF) within a Visited Public Land Mobile Network (VPLMN). PCRF 1026 may be communicatively coupled to application server 1030 via P-GW 1023. The application server 1030 may signal the PCRF 1026 to indicate the new service flow and select the appropriate quality of service (QoS) and charging parameters. The PCRF 1026 can provision this rule into a Policy and Charging Enforcement Function (PCEF) (not shown) using appropriate Traffic Flow Templates (TFTs) and QoS Class Identifiers (QCIs), which starts the QoS and charging specified by the application server 1030.

Fig. 11 illustrates example components of a device 1100, according to some embodiments. In some embodiments, device 1100 may include application circuitry 1102, baseband circuitry 1104, Radio Frequency (RF) circuitry 1106, front-end module (FEM) circuitry 1108, one or more antennas 1110, and Power Management Circuitry (PMC)1112 coupled together at least as shown. The illustrated components of the apparatus 1100 may be included in a UE or RAN node. In some embodiments, the apparatus 1100 may include fewer elements (e.g., the RAN node may not use the application circuitry 1102, but rather includes a processor/controller to process IP data received from the EPC). In some embodiments, device 1100 may include additional elements, such as memory/storage, a display, a camera, sensors, or input/output (I/O) interfaces. In other embodiments, the components described below may be included in more than one device (e.g., for a cloud RAN (C-RAN) implementation, the circuitry may be included separately in more than one device).

The application circuitry 1102 may include one or more application processors. For example, the application circuitry 1102 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 special-purpose processors (e.g., graphics processors, application processors, etc.). The processor may be coupled with or include memory/storage and may be configured to execute instructions stored in the memory/storage to enable various applications or operating systems to run on the device 1100. In some embodiments, a processor of application circuitry 1102 may process IP data packets received from the EPC.

The baseband circuitry 1104 may include circuitry such as, but not limited to, one or more single-core or multi-core processors. Baseband circuitry 1104 may include one or more baseband processors or control logic to process baseband signals received from the receive signal path of RF circuitry 1106 and to generate baseband signals for the transmit signal path of RF circuitry 1106. Baseband processing circuitry 1104 may interface with application circuitry 1102 to generate and process baseband signals and control the operation of RF circuitry 1106. For example, in some embodiments, baseband circuitry 1104 may include a third generation (3G) baseband processor 1104a, a fourth generation (4G) baseband processor 1104b, a fifth generation (5G) baseband processor 1104c, or other baseband processor(s) 1104d for other existing generations, generations in development, or generations to be developed in the future (e.g., second generation (2G), sixth generation (6G), etc.). Baseband circuitry 1104 (e.g., one or more of baseband processors 1104 a-d) may handle various radio control functions that enable communication with one or more radio networks via RF circuitry 1106. In other embodiments, some or all of the functionality of the baseband processors 1104a-d may be included in modules stored in the memory 1104g and executed via a Central Processing Unit (CPU)1104 e. The radio control functions may include, but are not limited to, signal modulation/demodulation, encoding/decoding, radio frequency offset, and the like. In some embodiments, the modulation/demodulation circuitry of baseband circuitry 1104 may include Fast Fourier Transform (FFT), precoding, or constellation mapping/demapping functionality. In some embodiments, the encoding/decoding circuitry of baseband circuitry 1104 may include convolution, tail-biting convolution, turbo, viterbi, or Low Density Parity Check (LDPC) encoder/decoder functionality. Embodiments of modulation/demodulation and encoder/decoder functions are not limited to these examples, and other suitable functions may be included in other embodiments.

In some embodiments, the baseband circuitry 1104 may include one or more audio Digital Signal Processors (DSPs) 1104 f. The audio DSP(s) 1104f may include elements for compression/decompression and echo cancellation, and may include other suitable processing elements in other embodiments. The components of the baseband circuitry may be combined as appropriate in a single chip, in a single chipset, or in some embodiments arranged on the same circuit board. In some embodiments, some or all of the constituent components of baseband circuitry 1104 and application circuitry 1102 may be implemented together, for example, on a system on a chip (SOC).

In some embodiments, the baseband circuitry 1104 may provide communications compatible with one or more radio technologies. For example, in some embodiments, baseband circuitry 1104 may support communication with an Evolved Universal Terrestrial Radio Access Network (EUTRAN) or other Wireless Metropolitan Area Network (WMAN), Wireless Local Area Network (WLAN), Wireless Personal Area Network (WPAN). Embodiments in which the baseband circuitry 1104 is configured to support radio communications of more than one wireless protocol may be referred to as multi-mode baseband circuitry.

RF circuitry 1106 may enable communication with a wireless network using modulated electromagnetic radiation through a non-solid medium. In various embodiments, the RF circuitry 1106 may include switches, filters, amplifiers, and the like to facilitate communication with a wireless network. RF circuitry 1106 may include a receive signal path that may include circuitry to down-convert RF signals received from FEM circuitry 1108 and provide baseband signals to baseband circuitry 1104. RF circuitry 1106 may also include a transmit signal path, which may include circuitry to up-convert baseband signals provided by baseband circuitry 1104 and provide RF output signals to FEM circuitry 1108 for transmission.

In some embodiments, the receive signal path of the RF circuitry 1106 may include mixer circuitry 1106a, amplifier circuitry 1106b, and filter circuitry 1106 c. In some embodiments, the transmit signal path of the RF circuitry 1106 may include filter circuitry 1106c and mixer circuitry 1106 a. The RF circuitry 1106 may also include synthesizer circuitry 1106d for synthesizing frequencies for use by the mixer circuitry 1106a of the receive signal path and the transmit signal path. In some embodiments, the mixer circuitry 1106a of the receive signal path may be configured to down-convert the RF signal received from the FEM circuitry 1108 based on the synthesized frequency provided by the synthesizer circuitry 1106 d. The amplifier circuit 1106b may be configured to amplify the downconverted signal and the filter circuit 1106c may be a Low Pass Filter (LPF) or a Band Pass Filter (BPF) configured to remove unwanted signals from the downconverted signal to generate an output baseband signal. The output baseband signal may be provided to baseband circuitry 1104 for further processing. In some embodiments, the output baseband signal may be a zero frequency baseband signal, although this is not a necessary requirement. In some embodiments, mixer circuitry 1106a of the receive signal path may comprise a passive mixer, although the scope of the embodiments is not limited in this respect.

In some embodiments, the mixer circuitry 1106a of the transmit signal path may be configured to up-convert the input baseband signal based on the synthesis frequency provided by the synthesizer circuitry 1106d to generate the RF output signal for the FEM circuitry 1108. The baseband signal may be provided by baseband circuitry 1104 and may be filtered by filter circuitry 1106 c.

In some embodiments, the mixer circuitry 1106a of the receive signal path and the mixer circuitry 1106a of the transmit signal path may comprise two or more mixers and may be arranged for quadrature down-conversion and up-conversion, respectively. In some embodiments, the mixer circuitry 1106a of the receive signal path and the mixer circuitry 1106a of the transmit signal path may comprise two or more mixers and may be arranged for image rejection (e.g., hartley image rejection). In some embodiments, the mixer circuitry 1106a and the mixer circuitry 1106a of the receive signal path may be arranged for direct down-conversion and direct up-conversion, respectively. In some embodiments, the mixer circuitry 1106a of the receive signal path and the mixer circuitry 1106a of the transmit signal path may be configured for superheterodyne operation.

In some embodiments, the output baseband signal and the input baseband signal may be analog baseband signals, although the scope of the embodiments is not limited in this respect. In some alternative embodiments, the output baseband signal and the input baseband signal may be digital baseband signals. In these alternative embodiments, RF circuitry 1106 may include analog-to-digital converter (ADC) and digital-to-analog converter (DAC) circuitry and baseband circuitry 1104 may include a digital baseband interface to communicate with RF circuitry 1106.

In some dual-mode embodiments, separate radio IC circuits may be provided to process signals for each spectrum, although the scope of the embodiments is not limited in this respect.

In some embodiments, synthesizer circuit 1106d may be a fractional-N synthesizer or a fractional-N/N +1 synthesizer, although the scope of the embodiments is not limited in this respect as other types of frequency synthesizers may be suitable. For example, the synthesizer circuit 1106d may be a delta-sigma synthesizer, a frequency multiplier, or a synthesizer including a phase locked loop with a frequency divider.

The synthesizer circuit 1106d may be configured to synthesize an output frequency for use by the mixer circuit 1106a of the RF circuit 1106 based on the frequency input and the divider control input. In some embodiments, the synthesizer circuit 1106d may be a fractional N/N +1 synthesizer.

In some embodiments, the frequency input may be provided by a Voltage Controlled Oscillator (VCO), although this is not a necessary requirement. The divider control input may be provided by baseband circuitry 1104 or application processor 1102 depending on the desired output frequency. In some embodiments, the divider control input (e.g., N) may be determined from a look-up table based on the channel indicated by the application processor 1102.

Synthesizer circuit 1106d of RF circuit 1106 may include a frequency divider, a Delay Locked Loop (DLL), a multiplexer, and a phase accumulator. In some embodiments, the divider may be a dual-mode divider (DMD) and the phase accumulator may be a Digital Phase Accumulator (DPA). In some embodiments, the DMD may be configured to divide an input signal by N or N +1 (e.g., based on a carry out) to provide a fractional divide ratio. In some example embodiments, a 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 decompose the VCO period into Nd equal phase packets, where Nd is the number of delay elements in the delay line. Thus, the DLL provides negative feedback to help ensure that the total delay through the delay line is one VCO cycle.

In some embodiments, the synthesizer circuit 1106d 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 the quadrature generator and frequency divider circuit to generate a plurality of signals at the carrier frequency having a plurality of different phases from one another. In some embodiments, the output frequency may be the LO frequency (fLO). In some embodiments, the RF circuitry 1106 may include an IQ/polar converter.

FEM circuitry 1108 may include a receive signal path that may include circuitry configured to operate on RF signals received from one or more antennas 1110, amplify the received signals, and provide amplified versions of the received signals to RF circuitry 1106 for further processing. FEM circuitry 1108 may also include a transmit signal path, which may include circuitry configured to amplify signals provided by RF circuitry 1106 for transmission by one or more of the one or more antennas 1110. In various embodiments, amplification by the transmit or receive signal path may be done in only RF circuitry 1106, only FEM 1108, or in both RF circuitry 1106 and FEM 1108.

In some embodiments, FEM circuit 1108 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 an LNA to amplify the received RF signal and provide the amplified receive RF signal as an output (e.g., to the RF circuitry 1106). The transmit signal path of FEM circuitry 1108 may include a Power Amplifier (PA) to amplify an input RF signal (e.g., provided by RF circuitry 1106) and one or more filters to generate the RF signal for subsequent transmission (e.g., by one or more of one or more antennas 1110).

In some embodiments, PMC 1112 may manage power provided to baseband circuitry 1104. Specifically, PMC 1112 may control power selection, voltage scaling, battery charging, or DC-to-DC conversion. PMC 1112 may often be included when device 1100 is capable of being battery powered, such as when the device is included in a UE. PMC 1112 may increase power conversion efficiency while providing desired implementation size and heat dissipation characteristics.

Although figure 11 shows PMC 1112 coupled only to baseband circuitry 1104. However, in other embodiments, PMC 1112 may additionally or alternatively be coupled to and perform similar power management operations for other components, such as, but not limited to, application circuitry 1102, RF circuitry 1106, or FEM 1108.

In some embodiments, PMC 1112 may control or otherwise be part of various power saving mechanisms of device 1100. For example, if the device 1100 is in an RRC _ Connected state that is still Connected to the RAN node because it is expected to receive traffic very soon, it may enter a state referred to as discontinuous reception mode (DRX) after a period of inactivity. During this state, device 1100 may be powered down for brief intervals and thereby conserve power.

If there is no data traffic activity for a longer period of time, the device 1100 may transition off to the RRC _ Idle state, in which it is disconnected from the network and no operations such as channel quality feedback, handover, etc. are performed. The device 1100 enters a very low power state and it performs a page in which it again periodically wakes up to listen to the network and then powers down again. Device 1100 may not receive data in this state and in order to receive data it must transition back to the RRC Connected state.

The additional power saving mode may allow the device to be unavailable to the network for periods longer than the paging interval (ranging from seconds to hours). During this time, the device is completely inaccessible to the network and can be completely powered down. Any data sent during this time is subject to a large delay and it is assumed that the delay is acceptable.

The processor of application circuitry 1102 and the processor of baseband circuitry 1104 may be used to execute elements of one or more instances of a protocol stack. For example, the processor of the baseband circuitry 1104, alone or in combination, may be used to perform layer 3, layer 2, or layer 1 functions, while the processor of the application circuitry 1104 may use data (e.g., packet data) received from these layers and further perform layer 4 functions (e.g., Transmission Communication Protocol (TCP) and User Datagram Protocol (UDP) layers). As referred to herein, layer 3 may include a Radio Resource Control (RRC) layer, which is described in more detail below. As referred to herein, layer 2 may include a Medium Access Control (MAC) layer, a Radio Link Control (RLC) layer, and a Packet Data Convergence Protocol (PDCP) layer, which are described in more detail below. Layer 1, as referred to herein, may comprise the Physical (PHY) layer of the UE/RAN node, which is described in more detail below.

Fig. 12 illustrates example interfaces of baseband circuitry, in accordance with some embodiments. As described above, the baseband circuitry 1104 of FIG. 11 may include processors 1104a-1104e and memory 1104g for use by the processors. Each of the processors 1104a-1104e can include a memory interface 1204a-1204e, respectively, for sending data to and receiving data from the memory 1104 g.

The baseband circuitry 1104 may also include one or more interfaces to communicatively couple to other circuitry/devices, such as a memory interface 1212 (e.g., an interface to send/receive data to/from a memory external to the baseband circuitry 1104), an application circuitry interface 1214 (e.g., an interface to send/receive data to/from the application circuitry 1102 of fig. 11), an RF circuitry interface 1216 (e.g., an interface to send/receive data to/from the RF circuitry 1106 of fig. 11), a wireless hardware connectivity interface 1218 (e.g., an interface to/from a Near Field Communication (NFC) component, a wireless network interface,

component (e.g. low energy consumption)

)、

Interfaces for components and other communicating components to send/receive data) and a power management interface 1220 (e.g., an interface to send/receive power or control signals to/from PMC 1112).

Fig. 13 provides an example illustration of a wireless device, such as a User Equipment (UE), Mobile Station (MS), mobile wireless device, mobile communication device, tablet device, handset, or other type of wireless device. A wireless device may include one or more antennas configured to communicate with a node, macro node, Low Power Node (LPN), or transmitting station, such as a Base Station (BS), evolved node b (enb), baseband processing unit (BBU), Remote Radio Head (RRH), Remote Radio Equipment (RRE), Relay Station (RS), Radio Equipment (RE), or other type of Wireless Wide Area Network (WWAN) access point. The wireless device may be configured to communicate using at least one wireless communication standard, such as, but not limited to, 3GPP LTE, WiMAX, High Speed Packet Access (HSPA), bluetooth, and WiFi. Wireless devices may communicate by using separate antennas for each wireless communication standard or shared antennas for multiple wireless communication standards. The wireless devices may communicate in a Wireless Local Area Network (WLAN), a Wireless Personal Area Network (WPAN), and/or a WWAN. The wireless device may also include a wireless modem. The wireless modem may, for example, include a wireless radio transceiver and baseband circuitry (e.g., a baseband processor). The wireless modem, in one example, can modulate signals transmitted by the wireless device via one or more antennas and demodulate signals received by the wireless device via one or more antennas.

Fig. 13 also provides an illustration of a microphone and one or more speakers that may be used for audio input and output from the wireless device. The display screen may be a Liquid Crystal Display (LCD) screen, or other type of display screen, such as an Organic Light Emitting Diode (OLED) display. The display screen may be configured as a touch screen. The touch screen may use capacitive, resistive, or another type of touch screen technology. The application processor and the graphics processor may be coupled to internal memory to provide processing and display capabilities. The non-volatile memory port may also be used to provide data input/output options to a user. The non-volatile memory port may also be used to expand the memory capabilities of the wireless device. The keyboard may be integrated with or wirelessly connected to the wireless device to provide additional user input. A virtual keyboard may also be provided using a touch screen.

Examples of the invention

The following examples relate to particular technology embodiments and indicate particular features, elements or actions that may be used or otherwise combined in implementing such embodiments.

Example 1 includes an apparatus of a user equipment operable to generate a demodulation reference signal (DM-RS) with reduced peak-to-average power ratio (PAPR), the apparatus comprising: one or more processors configured to: mapping, at the UE, complex pseudo-noise (PN) sequence symbols to one or more Code Division Multiplexing (CDM) groups; performing, on each of the one or more CDM groups, a CDM group-specific linear or non-linear operation on the complex PN sequence symbols mapped to the one or more CDM groups to generate DM-RSs having reduced PAPR; and encoding, at the UE, the DM-RS with reduced PAPR for transmission to a next generation node b (gnb), wherein the DM-RS is transmitted in a Physical Uplink Shared Channel (PUSCH) using cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) symbols; and a memory interface configured to transmit the mapped complex PN sequence symbols to a memory.

Example 2 includes the apparatus of example 1, further comprising a transceiver configured to transmit the DM-RS to the gNB.

Example 3 includes the apparatus of any of examples 1-2, wherein the one or more processors are further configured to: mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1; and mapping the complex conjugate of the original sequence value to a port in CDM group 2 to generate a type 1 DM-RS.

Example 4 includes the apparatus of any of examples 1 to 3, wherein the one or more processors are further configured to: mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1; mapping the complex conjugate of the original sequence value to a port in CDM group 2; and mapping phase shifted sequence values associated with the complex PN sequence symbols to ports in CDM group 3 to generate type 2 DM-RS.

Example 5 includes the apparatus of any of examples 1 to 4, wherein the one or more processors are further configured to: a CDM group-specific shift is applied to the sequence values mapped to the ports in CDM group 2 to generate type 1 DM-RS.

Example 6 includes the apparatus of any of examples 1 to 5, wherein the one or more processors are further configured to: a CDM group-specific shift is applied to the sequence values mapped to the ports in CDM group 2 and a different CDM group-specific phase shift is applied to the ports in CDM group 3 to generate type 2 DM-RS.

Example 7 includes an apparatus of a next generation node b (gnb) operable to generate a downlink reference signal with a reduced peak-to-average power ratio (PAPR), the apparatus comprising: one or more processors configured to: mapping complex pseudo-noise (PN) sequence symbols to one or more Code Division Multiplexing (CDM) groups at the gNB; performing, on each of the one or more CDM groups, a CDM group-specific linear or non-linear operation on the complex PN sequence symbols mapped to the one or more CDM groups to generate a downlink reference signal having a reduced PAPR; and encoding, at the gNB, a downlink reference signal having a reduced PAPR for transmission to a User Equipment (UE) over a Physical Downlink Shared Channel (PDSCH); and a memory interface configured to retrieve the mapped complex PN sequence symbols from memory.

Example 8 includes the apparatus of example 7, further comprising a transceiver configured to transmit the downlink reference signal to the UE.

Example 9 includes the apparatus of any one of examples 7 to 8, wherein the downlink reference signal is a demodulation reference signal (DM-RS) or a channel state information reference signal (CSI-RS).

Example 10 includes the apparatus of any of examples 7 to 9, wherein the one or more processors are further configured to: mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1; and mapping the complex conjugate of the original sequence value to a port in CDM group 2 to generate the downlink reference signal, wherein the downlink reference signal is a type 1 demodulation reference signal (DM-RS).

Example 11 includes the apparatus of any of examples 7 to 10, wherein the one or more processors are further configured to: mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1; mapping the complex conjugate of the original sequence value to a port in CDM group 2; and mapping phase shift sequence values associated with the complex PN sequence symbols to ports in CDM group 3 to generate the downlink reference signal, wherein the downlink reference signal is a type 2 demodulation reference signal (DM-RS).

Example 12 includes the apparatus of any of examples 7 to 11, wherein the one or more processors are further configured to: applying a CDM group-specific shift to sequence values mapped to ports in CDM group 2 to generate the downlink reference signal, wherein the downlink reference signal is a type 1 demodulation reference signal (DM-RS).

Example 13 includes the apparatus of any of examples 7 to 12, wherein the one or more processors are further configured to: applying a CDM group-specific shift to sequence values mapped to ports in CDM group 2 and applying a different CDM group-specific phase shift to ports in CDM group 3 to generate the downlink reference signal, wherein the downlink reference signal is a type 2 demodulation reference signal (DM-RS).

Example 14 includes the apparatus of any one of examples 7 to 13, wherein the one or more processors are further configured to: applying different CDM-group-specific phase shifts to ports in different frequency-domain CDM groups to generate the downlink reference signal, wherein the downlink reference signal is a channel state information reference signal (CSI-RS).

Example 15 includes at least one machine readable storage medium having instructions embodied thereon for generating a demodulation reference signal (DM-RS) with reduced peak-to-average power ratio (PAPR), the instructions, when executed by one or more processors at a User Equipment (UE), to: identifying, at the UE, one or more Code Division Multiplexing (CDM) group-specific initialization values; generating, at the UE, a CDM group-specific unique pseudo-noise (PN) sequence using the one or more CDM group-specific initialization values; generating, at the UE, a DM-RS with reduced PAPR using the CDM group-specific unique PN sequence; and encoding, at the UE, the DM-RS with reduced PAPR for transmission to a next generation node b (gnb).

Example 16 includes the at least one machine readable storage medium of example 15, further comprising instructions that when executed perform the following: sequence values are mapped to ports within each CDM group for DM-RS type 1 and DM-RS type 2 using the CDM group specific unique PN sequences.

Example 17 includes the at least one machine readable storage medium of any of examples 15 to 16, further comprising instructions that when executed perform operations comprising: determining the CDM group-specific initialization value for the CDM group-specific unique PN sequence for DM-RS type 1 and DM-RS type 2 using a Downlink Control Information (DCI) indication value of a binary scrambling Identifier (ID).

Example 18 includes the at least one machine readable storage medium of any of examples 15 to 17, further comprising instructions that when executed perform operations comprising: the CDM group-specific unique PN sequence is used when Downlink Control Information (DCI) formats 0_1 and 1_1 with a Cyclic Redundancy Check (CRC) scrambled by a cell radio network temporary identifier (C-RNTI), a configuration scheduling cell radio network temporary identifier (CS-RNTI), or a modulation coding scheme cell radio network temporary identifier (MCS-C-RNTI) are used.

Example 19 includes the at least one machine readable storage medium of any of examples 15 to 18, further comprising instructions that when executed perform operations comprising: decoding Radio Resource Control (RRC) configuration parameters received from the gNB for generating a low PAPR reference signal; and generating the DM-RS using the RRC configuration parameters.

Example 20 includes the at least one machine readable storage medium of any of examples 15 to 19, wherein the DM-RS is a user-specific reference signal for channel estimation for Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH) data demodulation.

Example 21 includes at least one machine readable storage medium having instructions embodied thereon for generating demodulation reference signals (DM-RSs) with reduced peak-to-average power ratio (PAPR), the instructions, when executed by one or more processors at a next generation node b (gnb), perform the following: identifying, at the gNB, one or more Code Division Multiplexing (CDM) group-specific initialization values; generating, at the gNB, a CDM group-specific unique pseudo-noise (PN) sequence using the one or more CDM group-specific initialization values; generating, at the gNB, DM-RSs with reduced PAPR using the CDM group-specific unique PN sequence; and encoding, at the gNB, the DM-RS with reduced PAPR for transmission to a User Equipment (UE).

Example 22 includes the at least one machine readable storage medium of example 21, further comprising instructions that when executed perform the following: sequence values are mapped to ports within each CDM group for DM-RS type 1 and DM-RS type 2 using the CDM group specific unique PN sequences.

Example 23 includes the at least one machine readable storage medium of any of examples 21 to 22, further comprising instructions that when executed perform operations comprising: determining the CDM group-specific initialization value for the CDM group-specific unique PN sequence for DM-RS type 1 and DM-RS type 2 using a Downlink Control Information (DCI) indication value of a binary scrambling Identifier (ID).

Example 24 includes the at least one machine readable storage medium of any of examples 21 to 23, further comprising instructions that when executed perform operations comprising: the CDM group-specific unique PN sequence is used when Downlink Control Information (DCI) formats 0_1 and 1_1 with a Cyclic Redundancy Check (CRC) scrambled by a cell radio network temporary identifier (C-RNTI), a configuration scheduling cell radio network temporary identifier (CS-RNTI), or a modulation coding scheme cell radio network temporary identifier (MCS-C-RNTI) are used.

The various techniques, or certain aspects or portions thereof, may take the form of program code (i.e., instructions) embodied in tangible media, such as floppy diskettes, compact disc read only memories (CD-ROMs), hard drives, non-transitory computer-readable storage media, or any other machine-readable storage medium, wherein, when the program code is loaded into and executed by a machine, such as a computer, the machine becomes an apparatus for practicing the various techniques. In the case of program code execution on programmable computers, the computing device may include a processor, a storage medium readable by the processor (including volatile and non-volatile memory and/or storage elements), at least one input device, and at least one output device. The volatile and non-volatile memory and/or storage elements may be Random Access Memory (RAM), erasable programmable read-only memory (EPROM), flash drives, optical drives, magnetic hard drives, solid state drives, or other media for storing electronic data. The nodes and wireless devices may also include a transceiver module (i.e., transceiver), a counter module (i.e., counter), a processing module (i.e., processor), and/or a clock module (i.e., clock) or timer module (i.e., timer). In one example, selected components of the transceiver module may be located in a cloud radio access network (C-RAN). One or more programs that may implement or use the various techniques described herein may use an Application Programming Interface (API), reusable controls, and the like. Such programs may be implemented in a high level procedural or object oriented programming language to communicate with a computer system. However, the program(s) can be implemented in assembly or machine language, if desired. In any case, the language may be a compiled or interpreted language, and combined with hardware implementations.

As used herein, the term "circuitry" may refer to, be part of, or include the following: 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 the functions associated with the circuitry may be implemented by, one or more software or firmware modules. In some embodiments, the circuitry may comprise logic operable, at least in part, in hardware.

It should be appreciated that many of the functional units described in this specification have been labeled as modules, in order to more clearly emphasize their implementation independence. For example, a module may be implemented as a hardware circuit comprising custom Very Large Scale Integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. A module may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices or the like.

Modules may also be implemented in software for execution by various types of processors. An identified module of executable code may, for instance, comprise one or more physical or logical blocks of computer instructions which may, for instance, be organized as an object, procedure, or function. Nevertheless, the executables of an identified module may not be physically located together, but may comprise disparate instructions stored in different locations which, when joined logically together, comprise the module and achieve the stated purpose for the module.

Indeed, a module of executable code may be a single instruction, or many instructions, and may even be distributed over several different code segments, among different programs, and across several memory devices. Similarly, operational data may be identified and illustrated herein within modules, and may be embodied in any suitable form and organized within any suitable type of data structure. The operational data may be collected as a single data set, or may be distributed over different locations including over different storage devices, and may exist, at least partially, merely as electronic signals on a system or network. A module may be passive or active, including an agent operable to perform a desired function.

Reference throughout this specification to "an example" or "exemplary" means that a particular feature, structure, or characteristic described in connection with the example is included in at least one embodiment of the present technology. Thus, the appearances of the phrase "in one example" or the word "exemplary" in various places throughout this specification are not necessarily all referring to the same embodiment.

As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list were individually identified as a separate and unique member. Thus, individual members of such lists should not be construed as equivalent to any other member of the same list solely based on their presentation in a common group without indications to the contrary. Moreover, various embodiments and examples of the present technology may be referred to herein along with alternatives for the various components thereof. It is to be understood that such embodiments, examples, and alternatives are not to be construed as true equivalents of one another, but are to be considered separate and autonomous representations of the present technology.

Furthermore, the described features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided, such as examples of layouts, distances, network examples, etc., to provide a thorough understanding of embodiments of the present technology. One skilled in the relevant art will recognize, however, that the technology can be practiced without one or more of the specific details, or with other methods, components, arrangements, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of the technology.

While the foregoing examples illustrate the principles of the present technology in one or more particular applications, it will be apparent to those of ordinary skill in the art that numerous modifications in form, usage and implementation details may be made without the exercise of inventive faculty, and without departing from the principles and concepts of the technology.

Claims (24)

1. An apparatus of a User Equipment (UE) operable to generate a demodulation reference signal (DM-RS) with reduced peak-to-average power ratio (PAPR), the apparatus comprising:

one or more processors configured to:

mapping, at the UE, complex pseudo-noise (PN) sequence symbols to one or more Code Division Multiplexing (CDM) groups;

performing, on each of the one or more CDM groups, a CDM group-specific linear or non-linear operation on the complex PN sequence symbols mapped to the one or more CDM groups to generate DM-RSs having reduced PAPR; and

encoding, at the UE, a DM-RS with reduced PAPR for transmission to a next generation node B (gNB), wherein the DM-RS is transmitted in a Physical Uplink Shared Channel (PUSCH) using cyclic prefix orthogonal frequency division multiplexing (CP-OFDM) symbols; and

a memory interface configured to: the mapped complex PN sequence symbols are transmitted to a memory.

2. The apparatus of claim 1, further comprising a transceiver configured to transmit the DM-RS to the gNB.

3. The apparatus of claim 1, wherein the one or more processors are further configured to:

mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1; and

mapping the complex conjugate of the original sequence value to a port in CDM group 2 to generate a type 1 DM-RS.

4. The apparatus of any of claims 1-3, wherein the one or more processors are further configured to:

mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1;

mapping the complex conjugate of the original sequence value to a port in CDM group 2; and

mapping phase shift sequence values associated with the complex PN sequence symbols to ports in CDM group 3 to generate a type 2 DM-RS.

5. The apparatus of any of claims 1-3, wherein the one or more processors are further configured to: a CDM group-specific shift is applied to the sequence values mapped to the ports in CDM group 2 to generate type 1 DM-RS.

6. The apparatus of any of claims 1-3, wherein the one or more processors are further configured to: a CDM group-specific shift is applied to the sequence values mapped to the ports in CDM group 2, and a different CDM group-specific phase shift is applied to the ports in CDM group 3 to generate type 2 DM-RS.

7. An apparatus of a next generation node b (gnb) operable to generate a downlink reference signal with a reduced peak-to-average power ratio (PAPR), the apparatus comprising:

one or more processors configured to:

mapping, at the gNB, complex pseudo-noise (PN) sequence symbols to one or more Code Division Multiplexing (CDM) groups;

performing, on each of the one or more CDM groups, a CDM group-specific linear or non-linear operation on the complex PN sequence symbols mapped to the one or more CDM groups to generate a downlink reference signal having a reduced PAPR; and

encoding, at the gNB, a downlink reference signal with a reduced PAPR for transmission to a User Equipment (UE) over a Physical Downlink Shared Channel (PDSCH); and

a memory interface configured to: the mapped complex PN sequence symbols are retrieved from memory.

8. The apparatus of claim 7, further comprising a transceiver configured to transmit the downlink reference signal to the UE.

9. The apparatus of claim 7, wherein the downlink reference signal is a demodulation reference signal (DM-RS) or a channel state information reference signal (CSI-RS).

10. The apparatus of any of claims 7-9, wherein the one or more processors are further configured to:

mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1; and

mapping a complex conjugate of the original sequence value to a port in CDM group 2 to generate the downlink reference signal, wherein the downlink reference signal is a type 1 demodulation reference signal (DM-RS).

11. The apparatus of any of claims 7-9, wherein the one or more processors are further configured to:

mapping an original sequence value associated with the complex PN sequence symbol to a port in CDM group 1;

mapping the complex conjugate of the original sequence value to a port in CDM group 2; and

mapping phase shift sequence values associated with the complex PN sequence symbols to ports in CDM group 3 to generate the downlink reference signal, wherein the downlink reference signal is a type 2 demodulation reference signal (DM-RS).

12. The apparatus of any of claims 7-9, wherein the one or more processors are further configured to: applying a CDM group-specific shift to a sequence value mapped to a port in CDM group 2 to generate the downlink reference signal, wherein the downlink reference signal is a type 1 demodulation reference signal (DM-RS).

13. The apparatus of any of claims 7-9, wherein the one or more processors are further configured to: applying a CDM group-specific shift to the sequence value mapped to the port in CDM group 2, and applying a different CDM group-specific phase shift to the port in CDM group 3 to generate the downlink reference signal, wherein the downlink reference signal is a type 2 demodulation reference signal (DM-RS).

14. The apparatus of claim 7, wherein the one or more processors are further configured to: applying different CDM-group specific phase shifts to ports in different frequency-domain CDM groups to generate the downlink reference signal, wherein the downlink reference signal is a channel state information reference signal (CSI-RS).

15. At least one machine readable storage medium having instructions stored thereon for generating a demodulation reference signal (DM-RS) with reduced peak-to-average power ratio (PAPR), the instructions when executed by one or more processors at a User Equipment (UE) perform the following:

identifying, at the UE, one or more Code Division Multiplexing (CDM) group-specific initialization values;

generating, at the UE, a CDM group-specific unique pseudo-noise (PN) sequence using the one or more CDM group-specific initialization values;

generating, at the UE, a DM-RS with reduced PAPR using the CDM group-specific unique PN sequence; and

at the UE, the DM-RS with reduced PAPR is encoded for transmission to a next generation node B (gNB).

16. The at least one machine readable storage medium of claim 15, further comprising instructions that when executed perform the following:

sequence values are mapped to ports within each CDM group for DM-RS type 1 and DM-RS type 2 using the CDM group-specific unique PN sequences.

17. The at least one machine readable storage medium of claim 15, further comprising instructions that when executed perform the following:

determining the CDM group-specific initialization value for the CDM group-specific unique PN sequence for DM-RS type 1 and DM-RS type 2 using a Downlink Control Information (DCI) indication value of a binary scrambling Identifier (ID).

18. The at least one machine readable storage medium of any of claims 15 to 17, further comprising instructions that when executed perform the following:

the CDM group-specific unique PN sequence is used when Downlink Control Information (DCI) formats 0_1 and 1_1 with a Cyclic Redundancy Check (CRC) scrambled by a cell radio network temporary identifier (C-RNTI), a configuration scheduling cell radio network temporary identifier (CS-RNTI), or a modulation coding scheme cell radio network temporary identifier (MCS-C-RNTI) are used.

19. The at least one machine readable storage medium of any of claims 15 to 17, further comprising instructions that when executed perform the following:

decoding Radio Resource Control (RRC) configuration parameters received from the gNB for generating a low PAPR reference signal; and

generating the DM-RS using the RRC configuration parameters.

20. The at least one machine readable storage medium of any one of claims 15 to 17, wherein the DM-RS is a user specific reference signal for channel estimation for Physical Downlink Shared Channel (PDSCH) and Physical Uplink Shared Channel (PUSCH) data demodulation.

21. At least one machine readable storage medium having instructions stored thereon for generating demodulation reference signals (DM-RSs) with reduced peak-to-average power ratio (PAPR), the instructions, when executed by one or more processors at a next generation node b (gnb), perform the following:

identifying, at the gNB, one or more Code Division Multiplexing (CDM) group-specific initialization values;

generating, at the gNB, a CDM group-specific unique pseudo-noise (PN) sequence using the one or more CDM group-specific initialization values;

generating, at the gNB, DM-RSs with reduced PAPR using the CDM group-specific unique PN sequence; and

at the gNB, DM-RSs with reduced PAPR are encoded for transmission to a User Equipment (UE).

22. The at least one machine readable storage medium of claim 21, further comprising instructions that when executed perform the following:

sequence values are mapped to ports within each CDM group for DM-RS type 1 and DM-RS type 2 using the CDM group-specific unique PN sequences.

23. The at least one machine readable storage medium of claim 21, further comprising instructions that when executed perform the following:

determining the CDM group-specific initialization value for the CDM group-specific unique PN sequence for DM-RS type 1 and DM-RS type 2 using a Downlink Control Information (DCI) indication value of a binary scrambling Identifier (ID).

24. The at least one machine readable storage medium of any of claims 21 to 23, further comprising instructions that when executed perform the following:

the CDM group-specific unique PN sequence is used when Downlink Control Information (DCI) formats 0_1 and 1_1 with a Cyclic Redundancy Check (CRC) scrambled by a cell radio network temporary identifier (C-RNTI), a configuration scheduling cell radio network temporary identifier (CS-RNTI), or a modulation coding scheme cell radio network temporary identifier (MCS-C-RNTI) are used.

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