Peak reduction tone allocation techniques

A transmitting device applies a first MCS to a first set of data tones that overlaps with a first set of PRTs within a plurality of tones, the first set of PRTs being associated with a first PAPR reduction signal. The transmitting device applies a second MCS to a second set of data tones that overlaps with a second set of PRTs within the plurality of tones, the second set of PRTs being associated with a second PAPR reduction signal. The transmitting device can transmit a transmission signal comprising the first set of data tones and the second set of data tones, the transmission signal using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal.

TECHNICAL FIELD

The present disclosure relates generally to communication systems, and more particularly, to a wireless communication involving a peak reduction tone allocation. Some embodiments enable and provide techniques for managing and/or reducing peak-to-average power ratio (PAPR) to aid in efficient system operations (e.g., non-saturated power amplifier operations) and/or resource usage (e.g., leveraging tone selection for opportunistic transmissions and quality communications).

INTRODUCTION

BRIEF SUMMARY

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided for wireless communication. In some aspects, the wireless communication may be performed at a transmitting device (e.g., user equipment, network node, or network equipment). The transmitting device may be configured to apply a first modulation and coding scheme (MCS) to a first set of data tones that overlaps with a first set of peak reduction tones (PRTs) within a plurality of tones, the first set of PRTs being associated with a first peak to average power ratio (PAPR) reduction signal. The transmitting device may be configured to apply a second MCS to a second set of data tones that overlaps with a second set of PRTs within the plurality of tones, the second set of PRTs being associated with a second PAPR reduction signal. Then, the transmitting device may be configured to transmit a transmission signal comprising the first set of data tones and the second set of data tones, the transmission signal using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided for wireless communication. In some aspects, the wireless communication may be performed at a transmitting device (e.g., user equipment, network node, or network equipment). The transmitting device may be configured to generate a first PAPR reduction signal from a first set of PRTs within a plurality of tones, where the first set of PRTs overlaps with a first set of data tones. The transmitting device may be configured to generate a second PAPR reduction signal from a second set of PRTs within the plurality of tones, where the second set of PRTs overlaps a second set data tones, where the first set of PRTs does not overlap with the second set of PRTs, and the first set of data tones does not overlap with the second set of data tones. Then, the transmitting device may be configured to apply a first MCS to the first set of data tones and a second MCS to the second set of data tones. Additionally, the transmitting device can transmit a data transmission using a waveform based at least in part on the first PAPR reduction signal with and second PAPR reduction signal.

In an aspect of the disclosure, a method, a computer-readable medium, and an apparatus are provided for wireless communication. In some aspects, the wireless communication may be performed at a receiving device (e.g., user equipment, network node, or network equipment). The receiving device may be configured to receive a data transmission from a transmitter having a first set of tones based on a first MCS and a second set of tones based on a second MCS, where at least one signal peak of the data transmission is reduced by a combination of a first PAPR reduction signal and a second PAPR reduction signal at the transmitter, where the first PAPR reduction signal comprises a first set of PRTs that overlaps a first set of data tones and the second PAPR reduction signal comprises a second set of PRTs that overlaps a second set of data tones, where the first set of data tones does not overlap with the second set of data tones. Then, the receiving device may be configured to decode the first set of data tones and cancels interference caused by the first set of data tones to the first set of peak reduction tones.

DETAILED DESCRIPTION

Techniques discussed herein generally relate to communication scenarios involving tone reservation and/or selection taking into account operational conditions. Aspects presented herein may improve the efficiency and performance of the tone reservation PAPR reduction technique by allocating PRTs based at least in part on the optimal Golomb ruler. Additionally, and/or alternatively, aspects presented herein may enable a transmitting device to use one or more kernels to construct/construct one or more peak cancellation signal to reduce the PAPR of the transmission. A “peak cancelling signal” may refer to a signal that reduces the PAPR of a combined signal transmission. Further, aspects presented herein may enable a receiving device to regenerate one or more peak(s) cancelled by a transmitting device to improve the SNR of the transmission.

FIG.1is a diagram illustrating an example of a wireless communications system and an access network100. While the examples below may use the UE104to illustrate the transmitting device and use the base station102to illustrate the receiving device, the UE104may also be the receiving device and the base station102may also be the transmitting device. For purpose of illustration, the UE104may be the transmitting device and the base station102may be the receiving device for the examples below.

In certain aspects, the UE104may include a peak reduction tone allocation component198configured to multiplex different MCS to one or more kernel, where a first kernel may allocate PRTs on the reserved tones of a plurality of tones, and a second kernel may allocate PRTs on the data tones of the plurality of tones. As used here, a “tone” is a single subcarrier in a frequency range. Then, the peak reduction tone allocation component198may assign different transmission power to the signals generated from the first kernel and the second kernel, and transmit the signals to the base station. In one configuration, the peak reduction tone allocation component198may be configured to generate a first peak to average power ratio (PAPR) reduction signal from a first set of PRTs within a plurality of tones, where the first set of PRTs overlaps with a first set of data tones. The PAPR may represent the ratio of the largest peak of a waveform and the square root of an average power of the waveform. In such configuration, the peak reduction tone allocation component198may further be configured to generate a second PAPR reduction signal from a second set of PRTs within the plurality of tones, where the second set of PRTs overlaps a second set data tones, where the first set of PRTs does not overlap with the second set of PRTs, and the first set of data tones does not overlap with the second set of data tones. In such configuration, the peak reduction tone allocation component198may further be configured to apply a first MCS to the first set of data tones and a second MCS to the second set of data tones. In such configuration, the peak reduction tone allocation component198may further be configured to transmit a data transmission using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal.

In certain aspects, the base station may include a peak reduction tone allocation estimation component199configured to receive the transmission comprising different MCS for different data tones, where the peak reduction tone allocation estimation component199may first decode data tones with lower MCS, remove the data tones with lower MCS after decoding, and then decode data tones with higher MCS. In one configuration, the peak reduction tone allocation estimation component199may be configured to receive a data transmission from a transmitter having a first set of tones based on a first MCS and a second set of tones based on a second MCS, where at least one signal peak of the data transmission is reduced by a combination of a first PAPR reduction signal and a second PAPR reduction signal at the transmitter, where the first PAPR reduction signal comprises a first set of PRTs that overlaps a first set of data tones and the second PAPR reduction signal comprises a second set of PRTs that overlaps a second set of data tones, where the first set of data tones does not overlap with the second set of data tones. In such configuration, the peak reduction tone allocation estimation component199may further be configured to decode the first set of data tones and canceling interference caused by the first set of data tones to the first set of peak reduction tones.

The EPC160may include a Mobility Management Entity (MME)162, other MMEs164, a Serving Gateway166, a Multimedia Broadcast Multicast Service (MBMS) Gateway168, a Broadcast Multicast Service Center (BM-SC)170, and a Packet Data Network (PDN) Gateway172. The MME162may be in communication with a Home Subscriber Server (HSS)174. The MME162is the control node that processes the signaling between the UEs104and the EPC160. Generally, the MME162provides bearer and connection management. All user Internet protocol (IP) packets are transferred through the Serving Gateway166, which itself is connected to the PDN Gateway172. The PDN Gateway172provides UE IP address allocation as well as other functions. The PDN Gateway172and the BM-SC170are connected to the IP Services176. The IP Services176may include the Internet, an intranet, an IP Multimedia Subsystem (IMS), a PS Streaming Service, and/or other IP services. The BM-SC170may provide functions for MBMS user service provisioning and delivery.

The BM-SC170may serve as an entry point for content provider MBMS transmission, may be used to authorize and initiate MBMS Bearer Services within a public land mobile network (PLMN), and may be used to schedule MBMS transmissions. The MBMS Gateway168may be used to distribute MBMS traffic to the base stations102belonging to a Multicast Broadcast Single Frequency Network (MBSFN) area broadcasting a particular service, and may be responsible for session management (start/stop) and for collecting eMBMS related charging information.

At least one of the TX processor368, the RX processor356, and the controller/processor359may be configured to perform aspects in connection with the peak reduction tone allocation component198ofFIG.1.

A power amplifier (PA) is a device that may be used to increase the magnitude (e.g., voltage, current, power, etc.) of an input signal. A PA may take in a weak electrical signal or waveform, and then reproduce a similar but stronger waveform at an output by using extra power. The design and implementation of PAs in wireless communications may help signals transmitted by transmitting devices to be strong enough to reach (e.g., to be received by) the receiving devices.

As a PA may consume extra power to magnify an input signal, a goal may be for a PA to have a linear relationship between an input signal and an output signal.FIG.4is a diagram400illustrating an example relationship between an input signal (Pin) and an output signal (Pout) for a PA with a linear behavior and a PA with non-linear behavior. For the PA with linear behavior402, the output signal (e.g., Pout-ideal) may be directly proportional to the input signal (e.g., Pin-ideal). For example, if 10 milliWatt of input signal power corresponds to 15 milliWatt of output signal power, then 20 milliWatt of input signal power may correspond to 30 milliWatt of output signal power, etc.

However, PAs may approximately follow the linear behavior for a limited range of input signals (e.g., within the linear region502as shown byFIG.5) and may have non-linear behavior outside the range of the input signals. As the output signal power of the PA may not increase indefinitely due to physical constrains, at some point (e.g., at the saturation point406), an increase in input signal power for the PA may not produce a discernible increase in the output signal power. Thus, the PA may follow non-linear behavior404as shown byFIG.4, and the non-linear behavior404may become particularly noticeable when the PA is operating at higher input signal powers (e.g., at the non-linear region504as shown byFIG.5). For example, when a PA is saturated (e.g., passing the saturation point406), the PA's output signal may no longer be proportional to the input signal, where a large increase in an input signal power beyond the saturation input signal power (e.g., Pin-sat) point may yield a relatively small increase in an output signal power from the saturation output signal power (e.g., Pout-sat) point. As the PA may consume a significant fraction of the power in a communication device, operating the PA beyond the saturation point may waste additional power, and may be an inefficient use of the PA. In addition, the non-linear behavior404of the PA may also result in in-band and out-of-band distortion of the signal, and may degrade error vector magnitude (EVM) at the receivers when the input signal power and the output power are not proportional.

To avoid operating a PA beyond the saturation point (e.g., to avoid the drawbacks of the non-linearity at high input power), the PA may be configured to operate at a mean input power that is several dB lower than the saturation point, such that the input signal power may not exceed the saturation input signal power (e.g., Pin-sat) point.FIG.5is a diagram500illustrating operating a PA at a mean input power (e.g., Pin-IBO). For example, for an input signal waveform508with a high peak to average power ratio (PAPR), the waveform508may be transmitted in the linear region502of the PA by decreasing the average power of the input signal (e.g., Pin). This may be referred to as an “input backoff” (IBO), which may result in a proportional “output backoff” (OBO). A PA may operate most efficiently when the IBO is close or equal to the PAPR of the input signal. For example, if an input signal has a PAPR of X dB, then an IBO of X dB may be applied to the PA to avoid the non-linearity. This enables the input signal to be amplified within the linear region502when the waveform508of the input signal is at the peak. For example, if the waveform508has a PAPR of 10 dB, and the PA also has an IBO equals or close to 10 dB, then the waveform508may be amplified within the linear region502without crossing the saturation point506(e.g., Pin-sat). This may prevent the output signal waveform510from distortion during an amplification, which may happen when the waveform508or part of the waveform508is amplified at the non-linear region504.

However, if a high IBO is applied to a PA but the input signal does not have a high PAPR (e.g., IBO>>PAPR), such as shown by diagram600A ofFIG.6A, it may be an inefficient use of the PA as it may reduce the maximum amplification of the PA. For example, a portion602of the linear region within the PA may be unused due to the high IBO, particularly the region close to the saturation points where a high input signal (e.g., near Pin-sat) may be amplified to nearly proportionate high output signal (e.g., near Pout-sat). This may limit the maximum performance of the PA and reduce a transmission range of a transmitting device. On the other hand, if the IBO applied to a PA is too low and the input signal has a PAPR that exceeds the IBO (e.g., PAPR>>IBO), such as shown by diagram600B ofFIG.6B, at least a portion (e.g., portion604) of the input signal may be amplified at the non-linear region of the PA, which may cause the output signal to be distorted and the bit error rate (BER) performance of a transmitting device may be degraded.

While OFDM signals may have tolerance to inter-symbol interference and good spectral efficiency, due to large fluctuations in their signal envelopes, OFDM signals may suffer from significant PAPR that may grow rapidly with the size of the OFDM block. For example, for a network that employs larger OFDM blocks, such as may be employed in 5G NR, the OFDM blocks may have higher PAPR. Due to the high PAPR, a PA designed for a communicating device capable of transmitting larger OFDM block(s) may be configured with a high IBO, which may result in an inefficient use of the PA when the communicating device is not transmitting signals with high PAPR, such as described in connection withFIG.6A. Therefore, as an alternative or in addition to applying a high IBO to the PA, PAPR reduction techniques may be used to reduce the PAPR of an input signal, such that the IBO applied to a PA may be kept at a lower value to maintain the spectral and energy efficiency of the PA. In addition, by reducing the PAPR, a PA may amplify the signal at a higher input power (e.g., as close to the saturation point as possible and within the linear region) and produce higher output signal.

In some examples, PAPR reduction techniques may be data-dependent and computationally expensive, which may make them unfit for a real-time implementation. For example, when a PAPR reduction mechanism is designed for the front end of a real-time transmission chain (e.g., to be operated on the fly), the PAPR reduction mechanism may have a relatively short time to process the input signal. For example, every time the PAPR reduction mechanism receives an OFDM symbol, it may have less than a millisecond to process the OFDM symbol to reduce the PAPR. For most PAPR techniques, a millisecond may not be enough as a lot of processing may be involved during the PAPR reduction. Clipping and filtering (CF) is one of the PAPR reduction techniques that may be used for real-time implementations, e.g., because of its low complexity and low processing time. However, CF and similar techniques may distort the signals themselves and result in in-band signal distortion, which may not converge to a desirable solution.

Cellular networks that operate in a higher and wider range of frequencies (e.g., 4G LTE, 5G NR, etc.) may have an abundance of bandwidth both in the uplink and downlink. This may include the addition of FR2 as well as the increase in the available bandwidth to 100 MHz in the sub-6 frequencies (i.e., frequencies under 6 GHz). Cellular networks with abundant or excess bandwidth may use longer OFDM symbols (e.g., larger OFDM blocks) for transmissions. While increasing the OFDM symbol size may increase the PAPR of the OFDM symbol as mentioned above, the excess bandwidth may also be used for PAPR reduction. For example, when a transmitting device such as a UE is transmitting in the uplink, there may be multiple free resource blocks available to the transmitting device.

In some techniques described herein, a transmitting device may use a tone reservation approach to reduce PAPR for an OFDM symbol. These techniques can include scenarios where a transmitting device may use unused, otherwise-idle, or reserved tones (e.g., unused or reserved subcarriers) of an OFDM symbol to accommodate a peak-cancelling signal that lowers PAPR of the OFDM symbol. For example, in a sample deployment scenario, the magnitude and the phase of reserved tones may be optimized for a given OFDM symbol to minimize PAPR. Additionally, or alternatively, a transmitting device may reserve some tones in subcarriers of an OFDM symbol, and the reserved tones may be used for PAPR reduction instead of transmitting data.

Tones used for PAPR reduction in reservation techniques may have a variety of features. For example, a tone reserved for PAPR reduction (e.g., tone containing the peak-cancelling signal) may be referred as a peak reduction tone (PRT). Given that, in some scenarios, there may be no overlap between one or more reserved tones and one or more data tones within one or more respective OFDM symbols (e.g., the reserved tones may be orthogonal with the data tones), a tone reservation scheme does not introduce any EVM and/or adjacent channel leakage ratio (ACLR) restrictions. Thus, a receiving device (e.g., a base station receiving the OFDM symbol) may be configured to block, disregard, ignore, and/or bypass signals in the reserved tones and decode signals in data tones. Bypassing and not decoding signals in reserved tones enables and provides improved device signal processing and improves communication throughput. As such, for purposes of the present disclosure, the reserved tones may also be referred to as “non-data tones,” which may include PRTs.

Varying tone characteristics can aid in some deployments. As one example, the magnitude and the phase of one or more reserved tones may be adjusted for each OFDM symbol to produce suitable PRTs. And the allocation of PRTs in each OFDM symbol may also be customized for optimized PAPR reduction. Additionally, or alternatively, a number of PRTs for each OFDM symbol may vary depending on the available bandwidth. While the location of PRTs may be determined on a per-OFDM symbol basis, fixing the location of PRTs for OFDM symbols in advance may reduce the complexity of the transmitting device. As the optimization (e.g., allocation) may be performed in advance instead of in real-time, the transmitting device's performance may be significantly improved. In addition, there may be a generally good index allocation for the PRTs within the OFDM symbol. As such, in some examples, for purposes of the present disclosure, the reserved tones may also be referred to as “non-data tones,” which may include PRTs.

FIG.7is a diagram700illustrating an example allocation of PRTs (e.g., reserved tones)702and data tones704(e.g., tone containing data information). The illustration depicts several tones within an OFDM symbol in the frequency domain. As can be seen, PRTs are disposed among data tones such that some data tones flank PRTs. In some aspects, allocation of PRTs702in an OFDM symbol enables low PAPR in the time domain. Transmitting devices may obtain the waveform of the OFDM symbol in time domain by taking the Inverse Fast Fourier Transform (IFFT) of the signal in frequency domain.FIG.7depicts a sample arrangement of PRTs and data tones and many other PRT/data tone arrangements may also be used given configurable nature of techniques discussed herein.

Indeed, as mentioned previously, transmitting devices may customize the location and the number of PRTs702for an OFDM symbol. Adaptive configuration enables flexibility considering communication operations and/or other factors (e.g., such as channel conditions, class/types of data transmission, etc.). For example, if a transmitting device (e.g., the UE) is granted two (2) resource blocks that include twenty-four (24) tones for transmission, the transmitting device may use half of the available tones (e.g., twelve (12) tones) as PRTs. The transmitting device may also choose any subset of the 24 available tones as long as the receiving device (e.g., the base station) is made aware of the transmitting device's choice, which may be configured through signaling and/or fixed in advance. For example, the transmitting device may choose subsets 1, 5, 6, 8, 10, 11, 12, 15, 16, 19, 21 and 22 for PRTs, and may inform its choice of subsets to the receiving device via signaling. In some examples, the subsets may be fixed in advance so that the receiving device may know which tones are PRTs without receiving additional signaling from the transmitting device.

If the location of the reserved tones is known by a transmitting device (e.g., a UE, a base station, etc.), the transmitting device may apply a signal to clipping noise ratio-tone reservation (SCR-TR) algorithm to the reserved tones to optimizes their values for PAPR reduction. For example, suppose a transmitting device is granted a total of N tones {1, . . . , N} (e.g., subsets 1-24 ofFIG.7) for transmission. Let P be a subset of {1, . . . , N} corresponding to the PRT locations (e.g., subsets 1, 5, 6, 8, 10-12, 15, 16, 19, 21 and 22 ofFIG.7). The data tones may be allocated to the remaining tones, {1, . . . , N}\ (e.g., subsets 2-4, 7, 9, 13, 14, 17, 18, 20, 23, 24 ofFIG.7). Then, a frequency domain kernel P may be constructed based on:

where Pimay denote the ithtone of the total granted tones N (e.g., P1=1sttone, P4=4thtone, P24=24thtone, etc.). Based on the frequency domain kernel, when the ithtone is a subset of Φ, a value of 1 may be assigned to the ithtone (e.g., subsets 1, 5, 6, 8 . . . ofFIG.7). When the ithtone is not a subset of Φ, a value of 0 may be assigned to the ithtone instead (e.g., subsets 2-4, 7, 9 . . . ofFIG.7). Next, let p denotes P in the time domain, where a time domain kernel p may be obtained by taking the IFFT of P, e.g., p=ifft(P), and let X denotes the frequency-domain data (e.g., data tones). As the value 0 is assigned to the ithtone when the ithtone is not a subset of Φ, naturally, Xi=0, if i∈Φ. For example, inFIG.7, X1and X5may be 0 as subsets 1 and 5 are within the subset of Φ, and X2and X7may not be 0 as subsets 2 and 7 are not within the subset of Φ, etc. Similarly, let x denotes X in time domain kernel, where x may be obtained by taking the IFFT of X, e.g., x=ifft(X). If the number of PRTs is sufficiently large and the location of the PRTs are chosen properly, then the time domain kernel p may look like a delta function with negligible side-lobes (shown inFIG.9).

FIG.8is a diagram800illustrating an example of a time domain data signal (e.g., x or an OFDM signal). A threshold806may be defined/configured for a transmitting device for determining whether a particular waveform of a time domain data has one or more peaks exceeding the threshold806, and the transmitting device may determine whether any of the one or more peaks is to be reduced. For example, based on the threshold806, a transmitting device may be able to determine that the waveform has a peak802and a peak804exceeding the threshold806. The transmitting device may also determine the magnitude and location of the peaks, and/or the largest peak among the peaks (e.g., the peak802).

FIG.9is a diagram900illustrating an example of a time domain kernel for p. If the number of PRTs is sufficiently large and the location of the PRTs are chosen properly, then the time domain kernel p may look like a delta function with negligible side-lobes as shown by the diagram900. For example, the time domain signal may appear as a waveform with a single peak906, where the single peak906may be relatively narrow in width compare to the largest peak of x (e.g.,802ofFIG.8). Next, the SCR-TR algorithm may circularly shift p in the time-domain until p aligns with the largest peak of x.

FIG.10is a diagram1000illustrating an example of circular shifting and alignment based on the SCR-TR algorithm. First, the SCR-TR algorithm may determine the location of the largest peak of x. Let j∈[LN] be the index, where L may denote an oversampling factor, N may denote a total number of granted tones and j may be an element of LN. Next, the algorithm circularly shifts p until the peak1006of p aligns with the largest peak1002of x, which may be represented by pj=circshift(p,j). The algorithm then subtracts the scaled and shifted p from x to obtain

xn⁢e⁢w=x-x⁡(j)-μp⁡(0)⁢pj⁢ei≺x⁡(j),
where μ is the target peak,x(j) is the phase of x(j), and i=√{square root over (−1)}. In other words, the cancellation signal may be circularly shifted to the peak location of x and then subtracted from the original information signal, so that the power of the peak tones may be reduced.

FIG.11is a diagram1100illustrating xnew, where the previous largest peak of x has been subtracted by the scaled and shifted p. The SCR-TR algorithm may iterate this process serval times to optimize the PAPR reduction. For example, the process may be performed in several iterations, starting from the highest peak and canceling one peak per iteration. As shown byFIG.11, after previous largest peak of x (e.g., the peak802,1002) is eliminated from x, the algorithm may circularly shift p to a next highest peak1104of x that is also above the threshold, and subtracted the peak1104by the scaled and shifted p and so on. Note that circularly shifting p in the time domain does not impact the location of reserved tones in the frequency domain, but it may disturb their phase. For example, phases may be added to P. However, as data tones (e.g., subsets 2-4, 7, 9 . . . ofFIG.7) are assigned with the value zero (0), their values may not be changed because adding phase to zero result in zero. On the other hand, the phase of PRTs may be modified because they are assigned with the value one (1). So, the PRT may become a complex number with magnitude one and the added phase. Thus, circularly shifting p does not impact the location of reserved tones. By applying the SCR-TR algorithm for the tone reservation, PAPR of the OFDM symbol may be reduced to a proper margin, and the corresponding PA may be configured with a lower IBO. For example, The OFDM symbol using 64 PRTs or 96 PRs may have an overall lower PAPR compare to the OFDM symbol that does not use any PRTs.

As shown inFIG.9, when the number of PRTs is sufficiently large and the location of the PRTs are chosen properly, the time domain kernel p may construct/construct a single narrow spike (e.g., the single peak906) with low and negligible side-lobes. However, if the number of PRTs is insufficient and/or when the location of the PRTs are not chosen properly, the signal and the waveform produced by the time domain kernel p may be less suitable for signal peak cancellation or reduction. For example, as shown by diagram1200ofFIG.12, when the reserved tones and their respective PRTs are located contiguously, the resulting waveform constructed by the time domain kernel p may have a wide peak1202and wide side-lobes. This waveform may be less desirable for signal peak cancellation as the wide peak1202may not be properly aligned with the largest peak in the time domain data signal (e.g., the peak802inFIG.8), and may overlap with other portion(s) of the time domain data signal. This may result in more peaks being created (e.g., generated) at other places when the waveform inFIG.12is applied to the time domain signal for signal peak reduction. As shown byFIG.13, when the reserved tones and their respective PRTs are located uniformly (e.g., spacing between PRTs is uniform), the resulting waveform1300generated by the time domain kernel p may have a narrow peak1302. However, the waveform may also produce side-lobes1304with one or more peaks that may be as high as the peak1302. While the peak1302may be aligned with the highest peak of the time domain data signal for signal peak reduction or cancellation, other peaks on the side-lobes1304may create additional peaks during signal peak cancellation.

As shown byFIG.14, when the reserved tones and their respective PRTs are located randomly, the resulting waveform1400generated by the time domain kernel p may have a main peak1402that is tall and narrow, and the peaks of side-lobes1404may be shorter than the main peak1402, which may appear as having the characteristic of combining both waveforms inFIGS.12and13. While the peaks on the side-lobes1404may create additional peaks when this waveform is used for signal peak reduction or cancellation, the increase may be moderate and may not be as high as the increase created by the waveform inFIG.13. Thus, the waveform inFIG.14may be more suitable for signal peak reduction than the waveforms inFIGS.12and13, and may be used for reducing the PAPR of the time domain signal. However, as allocating PRTs randomly may yield unpredictable and/or random results, the way in which the random number is generated and chosen at the time domain kernel p may further be configured and optimized to increase the likelihood that the resulting waveform would have a single narrow peak with low side-lobes, such as the waveform shown byFIG.9.

As illustrated in connection withFIGS.9to14, a signal or waveform suitable for reducing a peak of another signal may include a single peak with low side-lobes. Thus, as shown by diagram1500inFIG.15, an optimized waveform1506(e.g., waveform represented by solid line) for signal peak cancellation or reduction may include a single narrow peak1502and have no side-lobes1504, which may be referred as an “ideal” or “perfect” waveform or a waveform produced by an “ideal” or “perfect” kernel for purpose of illustration below.

Techniques discussed herein can provide a number of benefits. For example, some aspects presented herein may enable a time domain kernel to select the location (e.g., sequence) of PRTs and construct a waveform that resembles or is close to the waveform1506ofFIG.15. In one example, a sequence may have n elements a0, . . . , an-1, with ai∈{0,1}, where aiis either 0 or 1 and 1 may correspond to the PRT and 0 may correspond to the data tone, such as described in connection with Piof the frequency domain kernel P above. The modular autocorrelation bjof the sequence may be defined by:
bj=ρi=0n-1aiamod(i+j,n)forj=0, . . . ,n−1.
For example, the sequence (e.g., a0, . . . , an-1) may be circularly shifted in the frequency domain. Thus, if each element aiin the original sequence is multiplied by its circular shift (e.g., amod(i+j,n)), the sum of the resulting elements may yield the autocorrelation bjof the sequence.

The autocorrelation of the sequence may be referred as a “perfect” autocorrelation if bj=constant for j≠0, such that a sequence a0, . . . , an-1with the “perfect” autocorrelation may construct/construct a “perfect” time domain kernel (e.g., kernel that produces “ideal” waveform1506) as ifft(a). For example, a “perfect” autocorrelation b1may be represented by:

bj={c,j=0d,j≠0↔[ifft⁡(b)]j={c+d⁡(n-1),j=0c-d,j≠0,
where the value of b is high when j=0, and the value of b is low when j≠0. The “perfect” frequency domain kernel (e.g., ifft(a)) may then be derived from |ifft(a)|=√{square root over (|ifft(b)|)}. Accordingly, a “perfect” autocorrelation may be generated for a sequence when elements (e.g., 0 and 1) of the sequence are properly chosen.

Additionally, or alternatively, some aspects presented herein may be referred to as a “difference set,” which may be used to determine one or more sequences that may construct/construct a “perfect” autocorrelation. In one example, for a sequence with n elements a0, . . . , an-1with ai∈{0,1}, such as described above, let S⊆{0, . . . , n−1} represents the non-zero indices of a. In other words, S may be a subset of 0 to n−1 and may include all the indices for which the aiis equal to 1. For example, if a sequence a=[1 1 0 0 0 1 0], then S may include index 0, index 1 and index 5 (e.g., a0, a1and a5) in the subset as they are equal to 1. Thus, S may also be represented as S={0,1,5}⊆{0,1, . . . , 6}, etc.

Next, the elements aiwithin the sequence a0, . . . , an-1may be chosen in a way where the difference between any pair of elements within the sequence is different from other pair. For example, referring to the example above where S={0,1,5}, the difference between any pair of elements within the set is different as the difference between 0 and 1 is 1, difference between 1 and 5 is 4, and difference between 0 and 5 is 5. Thus, the three possible pair differences in this set would be 1, 4 and 5 where the difference between any pair of elements is distinct (i.e., not the same as other pairs). The difference between the pair of elements may also be referred as the “pairwise differences” of the elements, and a subset S comprising pairwise differences of elements may be referred as a “difference set.”

Accordingly, the autocorrelation b of the sequence may alternatively be defined as:
bj=Σi=0n-11{{i,mod(i+j,n)}⊆S}forj=0, . . . ,n−1,
or
bj=Σ{i,k}⊆S1{mod(k-i,n)=j}forj=0, . . . ,n−1.
Thus, for a given sequence a0, . . . , an-1with corresponding S, the autocorrelation b may be “perfect” if every j∈{1, . . . , n−1} can be written in exactly λ ways as difference of elements of S, where λ may be independent of j. The set S may then be considered as a “difference set” with repetition λ. As the value one (1) within the sequence may correspond to a PRT (e.g., location of each PRT) and the value zero (0) may correspond to a data tone, for a “difference set” S with repetition λ, the square of a total number of PRTs (e.g., numPRT) within the sequence may approximately equal to a total number of tones (e.g., numTones) multiplied by λ, such that numPRT2≅numTones×λ. By choosing zeros (0) and ones (1) for the sequence a0, . . . , an-1based on the above-mentioned approach, a “perfect” autocorrelation b for the sequence may be created, and a “perfect” kernel may then be constructed based on the “perfect” autocorrelation.

In one example, a “perfect ruler” may be used to determine the allocation of zeros (0) and ones (1) within the sequence a0, . . . , an-1. A perfect ruler may be a set of integers S⊆{0, . . . , n−1} where the pairwise differences of the elements of S modulus n form a closed interval of integers. In addition, a perfect ruler may correspond to a “difference set” with λ=1, meaning that each difference (e.g., difference between a pair of elements within the sequence) may be repeated once. As the perfect ruler or integers within the perfect ruler complies with the requirement of creating the “perfect” autocorrelation (e.g., having a subset S with “difference set” and repetition λ=1), using the perfect ruler to allocate PRTs (e.g., using S as PRT indices) may result in a “perfect” kernel.

For example, referring back to the example where the subset S={0,1,5} S{0,1, . . . , 6}. The difference set of S may be represented by a vector having six possible combinations: {1−0, 5−0, 0−1, 0−5, 1−5, 5−1}, which may result in {1, 5, −1, −5, −4, 4}. A modulo operation (e.g., mod) may then be applied to this vector to convert values or numbers within the vector to non-negative numbers. The modulo operation may be used to find the remainder or signed remainder after division of one number by another. For example, for two numbers, a and n, a modulo n (or a mod n) is the remainder of the Euclidean division of a by n, where a is the dividend and n is the divisor. To convert all values within the vector to non-negative numbers, a number that is higher than the total number of elements in the vector (e.g., such as by 1) may be chosen as the divisor n for performing the modulo operation for all the values in the vector. For example, as the vector has six elements, a number that is larger than 6, such as 7, may be chosen as the divisor, such that {1, 5, −1, −5, −4, 4} mod 7={1, 5, 6, 2, 3, 4} (e.g., 1 mod 7=1, −1 mod 7=6, −4 mod 7=3, etc.). In other words, what mod may do to the vector is that when an element (e.g., integer) in the vector is greater than 0 and less than the divisor, the mod may do nothing. On the other hand, when the integer in the vector is less than 0, such as a negative number, then the mod number (e.g., 7) may be added to the negative integer (e.g., 1 mod 7=1, 5 mod 7=5, 4 mod 7=4, etc.). Thus, {1, 5, −1, −5, −4, 4} mod 7 becomes {1, 5, −1+7, −5+7, −4+7, 4} and yields {1, 5, 6, 2, 3, 4}. Further, it may be observed that the resulted numbers (e.g., elements) in the vector after applying the mod may include a set of consecutive numbers (e.g., 1, 2, 3, 4, 5, 6 in this example). Thus, to construct a “perfect” kernel, the chosen subset S (e.g., location of the PRTs) may include and follow this property, where the difference between all possible pairs of elements (or pair combinations) within the sequence provide a closed interval of integers (e.g., the perfect ruler). This may again be referred as the “difference set.” In other words, one way a “perfect” kernel may be constructed is to choose a subset S that yields a consecutive pair differences (e.g., after applying mod) where each difference appears once. For example, the possible pair differences in the example above, after applying modulo operation, yields a consecutive sequence 1, 2, 3, 4, 5, 6 where no number within the sequence repeated (e.g., same as another number). Thus, if a set of PRTs are allocated based on the subset S={0,1,5}, such that a=[1 1 0 0 0 1 0]→a*ā=[3 1 1 1 1 1 1]→ifft(a*ā)=[9 2 2 2 2 2 2]→|ifft(a)|=[3 1.4 1.4 1.4 1.4 1.4 1.4]. The values may represent a “perfect” kernel in time domain as it may have one main peak (e.g., corresponding to the value 3), and everything else outside the peak may be flat (e.g., all other values are 1.4), etc.

In another example, or as an alternative, a “Golomb ruler” or an “optimal Golomb ruler” may be used to determine the allocation of 0 and 1 within the sequence a0, . . . , an-1. An optimal Golomb ruler may be a set of integers S⊆{0, . . . , n−1} where the pairwise differences of the elements of S modulus n are distinct. In other words, the optimal Golomb ruler may be a set of integers where no two pairs of integers have the same difference. For example, the sequence [0, 1, 4, 6] and the sequence [0, 2, 7, 8, 11] may have the property of the optimal Golomb ruler as the difference between any pair of integers within the sequence is distinct and different from other pairs. Table 1 below is an example illustrating different sets of integers or sequence that may consider to have the property of the optimal Golomb ruler. The integers/elements in Table 1 may be used as the prime candidates for the location of PRTs within a plurality of tones. In addition, if an increment or an offset (e.g., 1, 5, 10, etc.) is applied to the set of integers/elements to the in Table 1, the resulting value may still maintain the property of the optimal Golomb ruler. For example, if an offset or increment 10 is applied to the sequence [0, 1, 4, 6], the resulting sequence [10, 11, 14, 16] may still maintain the property of the optimal Golomb ruler as the difference between any pair of integers within the sequence may be distinct.

The allocation of PRTs based on the optimal Golomb ruler may provide higher or better PAPR reduction than allocating PRTs randomly, such as described in connection withFIG.14. For example, an optimal (e.g., maximally dense) Golomb ruler may maximize |S| for a given n, where n may be a total number of tones and S may correspond to the order number in Table 1 (e.g., number of elements/integers within the set). Thus, for specific choices of n, the optimal Golomb ruler may function as a perfect ruler. While constructing an optimal Golomb ruler may be time consuming or difficult as the number of integers (e.g., tones) increases, efficient constructions for near-optimal Golomb rulers may be used, such as by using the Ruzsa construction. The Ruzsa construction may provide a fast and efficient construction, which may provide Golomb rulers with p−1 elements for every prime number p. For example, S may be determined by:
S=p*(1:p−1)+(p−1)*g1:p-1modp(p−1),
where p may be a prime and g may be a primitive root ofp. Based on this construction, |S|=p−1 and n=p(p−1), and the approximate maximal or optimal value for |S| may be obtained. For example, if |S|=7, then the integer set {0, 1, 4, 10, 18, 23, 25} within order #7 in Table 1 may be used to allocate the PRTs. As such, a near “perfect” kernel may be constructed by determining the |S| and allocating the PRTs based on the corresponding optimal Golomb ruler set, such as illustrated in Table 1.

For example, a UE may first determine an order of the optimal Golomb ruler (e.g., the order # in Table 1) and optionally an offset. In one aspect, the UE may determine the order number by finding the square root of the number of allocated tones (e.g., total tones) and rounding this square root number to the closest integer (e.g., whole number). For example, if total number of tones is 71, the UE may calculate the square root of 71, which is approximately 8.426, and the UE may round this number to the closest whole number (e.g., 8). Depending on the configuration, the UE may add a constant (e.g., 1) to the rounded whole number to obtain the order number for the Golomb ruler (e.g., the order number in Table 1). Then, the UE may choose the optimal Golomb ruler of an appropriate order from Table 1 based on the obtained order number. In some examples, to align the integers associated with the selected order number from the Golomb ruler to the allocated tones, the UE may apply an offset to the marks within the selected order number such that the first mark within the selected order number (e.g., the first mark on the selected order of the Golomb ruler) may correspond to the first allocated tone. Then, the UE may determine the PRT indices or location of PRTs based on integers with the offset.

Techniques discussed herein can provide a number of benefits. For example, some aspects presented herein may reduce the PAPR of a transmission, where one or more kernel may be used at a transmitting device (e.g., the UE) to construct/construct peak-cancelling signals (e.g., PAPR reduction signal) to cancel or reduce one or more peaks of the data transmission. Additionally, in some aspects, a receiving device (e.g., the base station) may receive the data transmission and be configured to regenerate the one or more peak(s) cancelled by the transmitting device. This may effectively reduce or mitigate some impact that may be associated with signal cancellation or reduction, such as reduction in signal-to-noise ratio (SNR) of the channel, while achieving the PAPR reduction for the transmission.

In one aspect of the present disclosure, two kernels (e.g., kernel-1 and kernel-2) may be used by a transmitting device (e.g., a UE, a base station) for peak cancellation, where each kernel may construct a peak cancelling signal based on its respective PRTs, such as described in connection withFIGS.9-11and15.FIG.16is a diagram1600illustrating an example of allocating PRTs for two kernels. In one aspect, for a transmission with a set of tones1602including multiple reserve tones1604and data tones1606, PRTs1608for kernel-1 may be allocated to or within the reserved tones1604, and the location of the PRTs1608for kernel-1 may not overlap with the data tones1606. PRTs1610for kernel-2 may be allocated to or within the data tones1606, and the location of the PRTs1610for kernel-2 may partially or fully overlap with the data tones1606. The location of the PRTs1610for kernel-2 may not overlap with the reserved tones1604, such that the PRTs1608for kernel-1 does not overlap with the PRTs for1610kernel-2.

FIG.17is a diagram1700illustrating an example waveform generated by kernel-1, such as described in connection withFIGS.9-11and15. As the location of the PRTs1608for kernel-1 may be confined to reserved tones1604, while the peak cancelling signal generated by kernel-2 may have moderate to high side-lobes1704with a single peak1702, the peak cancelling signal generated by kernel-1 may not introduce EVM, such as described in connection withFIG.5. In addition, allocating PRTs to reserved tones1604may not add any distortion to the signal. However, the peak cancelling signal generated by kernel-1 may introduce peak regrowth at some of the peak signals (e.g., of the OFDM signal) because of the moderate to high side-lobes1704. This may reduce the efficiency of the peak cancelling signal, where less PAPR may be reduced. For example, the side-lobes1704may limit the peak cancelling signal to provide a moderate PAPR reduction, such that the PAPR may be unable to go below certain threshold (e.g., 7 dB, 20 dB, etc.). The PRT allocation mechanism described in connection withFIG.15(e.g., perfect ruler, Golomb ruler, etc.) may be used for locating PRTs for kernel-1.

FIG.18is a diagram1800illustrating an example waveform generated by kernel-2, such as described in connection withFIGS.9-11and15. As the location of the PRTs1610for kernel-2 may overlap with data tones which may be larger than the reserved tones, this may provide kernel-2 with more option to allocate PRTs and optimize the peak cancelling signal. Thus, the peak cancelling signal generated by kernel-2 may have lower side-lobes1804with a single peak1802, and may introduce very limited or no peak regrowth. However, as the PRTs1610for kernel-2 may overlap with data tones1606, either in full or in part, the signal may be distorted in the frequency domain. In addition, the peak cancelling signal generated by kernel-2 may introduce EVM.

As peak reduction signals generated by kernel-1 and kernel-2 may have different characteristics, such as described in connection withFIGS.17and18, in one aspect of the present disclosure, a linear combination may be applied to kernel-1 and kernel-2 to combine the peak cancelling signals generated from kernel-1 and kernel-2. In other words, the signal generated from kernel-1 (e.g., Signal1) may be combined with the signal generated from kernel-2 (e.g., Signal2) to form a combined signal (e.g., Signal3). In on example, Signal1may be linearly combined with Signal2by first applying a ratio α (e.g., 0≤α≤1) to Signal1and applying another ratio (1−α) to Signal2, and then combining the resulting signals to construct/construct Signal3, such that Signal3=α*Signal1+(1−α)*Signal2. By linearly combining Signal1and Signal2, the negative effects (e.g., peak regrowth, EVM, etc.) associated with each signal may be reduced. In one other aspect of the present disclosure, the ratio applied to Signal1and the ratio applied to Signal2may not equal 1. For example, a first ratio (e.g., α) may apply to Signal1, and a second ratio (e.g., β) may apply to the Signal2, such that Signal3=α*Signal1+β*Signal2and α+β does not equal to 1. Note that while the linear combination of Signal1and Signal2here is described as generating a new peak cancelling signal (e.g., Signal3), a transmitting device may also apply the signal from kernel-1 (e.g., Signal1) and the signal from kernel-2 (e.g., Signal2) separately to the data transmission without combining them (e.g., no Signal3is generated). Thus, for purpose of illustration below, linear combination may refer to linearly combining one or more signal into a new signal, or applying one or more signal having linear combination relation separately.

Referring to the example above regarding the frequency domain kernel P, where a transmission is granted a total of N tones {1, . . . , N}, Φrepresents a subset of {1, . . . , N} corresponding to the PRT locations and data tones are allocated to the remaining tones {1, . . . , N}\Φ, such as described in connection withFIG.7. Kernel-1 in frequency domain may be represented by:

The time domain kernel of kernel-1 may be denoted as pkernal-1, which may be obtained by taking the IFFT of kernel-1 P. On the other hand, as kernel-2 allocates its PRTs on data tones instead of reserved tones, kernel-2 in frequency domain may be represented by:

Similarly, the time domain kernel of kernel-2 may be denoted as pkernel-2, which may be obtained by taking the IFFT of kernel-2 P As the SCR-TR algorithm may be used to determine the location of the largest peak of a waveform, the combined signal (e.g., Signal3) from kernel-1 and kernel-2 may be circularly shifted to the highest peak of a waveform z to cancel or reduce the highest peak (e.g., the highest peak of z is subtracted by the scaled and shifted Signal3) to reduce the PAPR of the waveform z, such as described in connection withFIG.10. Thus, the resulting waveform znew(e.g., after applying circular shift) may be represented by:
znew=z−(|z(j)|−μ)·circhift(αpkernel1+(1−α)pkernel2,j).

FIG.19is a diagram1900illustrating an example signal peak reduction involving kernel-1 (e.g., as described in connection withFIGS.8to11) and both kernel-1 and kernel-2. By applying the linearly combined signal (e.g., Signal3) from kernel-1 and kernel-2, the resulting waveform1906(e.g., waveform znew) may have overall lower peaks than the original waveform1902(e.g., waveform z) and the waveform1904that applies peak cancelling signal from just kernel-1 (e.g., Signal1). The combined peak cancellation signal (e.g., Signal3) thus may provide a better PAPR reduction for the data transmission, and the threshold described in connection withFIG.17may further be lowered.

FIG.20is a diagram2000illustrating an example signal peak reduction involving linear combination of kernel-1 and kernel-2 at a transmitting device (e.g., the UE104,350, etc.) according to aspects of the present disclosure. At2002, a transmitting device may generate an output signal S(f) in frequency domain, such as for a data transmission. At2004, the output signal S(f) may be converted into an output time domain signal s(t) by applying iFFT to the S(f), then highest N peak(s) of the s(t) may be identified, such as described in connection withFIGS.8-11. At2006, peak cancellation signal generated from kernel-2 (e.g., the p(t)) multiplied by a (e.g., the ratio for linear combination) may be applied to the s(t) to cancel or reduce highest N peak(s) of s(t) (e.g., represented by dotted circle associated with2004and2006). At2008, a resulting signal x(t) may be generated after signal peak reduction (e.g., circular shift) is applied to the s(t). At2010, the resulting time domain signal x(t) may be converted back to a frequency domain signal X(f) by applying FFT to the x(t). At2012, frequency domain signal Y(f) from kernel-1 (e.g., with PRTs allocated on reserve tones) is multiplied by (1−α) and added to/combined with the X(f), and an output signal is generated at2014for transmission. As the reserved tones and their respective PRTs at2012do not overlap with data tones at2010, the two may be combined without overlapping each other, such as shown at2014. The PRTs allocated by kernel-1 may further be used to construct/construct peak cancelling signal (e.g., Signal1) to further reduce the N peaks of x(t), such as described in connection withFIGS.7to11. While this example shows the signal from kernel-2 being applied to the output signal S(f) before applying the signal from kernel-1, the signal from kernel-1 may also be applied to the output signal S(f) before the signal from kernel-2. Signals from kernel-1 and kernel-2 may also be applied to the output signal S(f) simultaneously, or be combined before applying to the output signal S(f) (e.g., generating Signal3), etc.

Aspects presented herein may reduce distortion of a transmitted signal (e.g., data transmission) and improve the SNR of the channel at a receiving device (e.g., base station102,180,310), where the receiving device may be configured to regenerate one or more peak being cancelled at the transmitting device, such as the peak cancellation described in connection withFIGS.16-20. Thus, distortion or EVM introduced during signal peak cancellation process, such as by kernel-2, may be mitigated or removed, and the transmitted signal may be compensated.

In one aspect, to regenerate one or more peak cancelled at a transmitting device, the receiving device may be configured first to identify the location of the cancelled peak(s) and/or the magnitude of the cancelled peak(s) in a received signal (e.g., the signal transmitted from the transmitting device). If the transmitting device is able to identify the location and magnitude of the cancelled peak(s), the transmitting device may regenerate the cancelled peak(s). For example, a reversed process of signal cancellation described in connection withFIGS.16-20may be applied to the received signal, where the peak cancellation signal(s) (e.g., Signal1generated by kernel-1, Signal2generated by kernel-2, etc.) may be circularly shifted to the identified cancelled peak location(s) and added to the received signal instead of subtracted from the received signal.

In one example, let z(t)=x(t)+y(t) be a received signal (e.g.,1602,2014) in time domain where x(t) may represent the data tones and y(t) may represent the PRTs (or reserved tones including PRTs), such as described in connection with the example kernel-1 and kernel-2 above. In one aspect, for a receiving device to identify the location and magnitude of the cancelled peak(s), the receiving device may first transfer z(t)=x(t)+y(t) into frequency domain (e.g., Z(f)=X(f)+Y(f)), and the receiving device may set Y(f) to zero in the frequency domain such that Z(f)=X(f). As Y(f) is confined to reserved tones and does not overlap with data tones, Y(f) may be identified and removed from Z(f) (e.g., by setting the value of the identified reserved tones to 0).

FIG.21is a diagram2100illustrating an example of a received signal (e.g., z(t)) observed at a receiving device. A waveform2102may represent z(t), the received signal; a waveform2104may represent x(t), the data tones; and a waveform2106may represent y(t), the reserved tones or PRTs. The waveform2104for x(t) may be obtained by setting y(t) to 0, such as described in connection with Y(f) above. By observing the waveform2102(e.g., z(t)) and the waveform2104(e.g., x(t)), the receiving device may be able to determine the location and magnitude of the peak(s) cancelled by PRTs in y(t) (e.g., by the cancellation signal generated from kernel-1) at the transmitting device.

In one aspect, the receiving device may obtain the location of the cancelled peak(s) by comparing the phase of z(t) and x(t), where the phase may match at the cancelled peak location. For example, the receiving device may decide whether a peak was cancelled at cancelled at t0by defining that |x(t0)|>target_peak, wherex(t0)≈y(t0) such that y(t) has a peak at y(t0). The receiving device may obtain the magnitude of the cancelled peak(s) based on the difference (e.g.,2108) between the peak of the waveform2012and the peak of the waveform2014. Thus, the transmitting device may be able to regenerate the cancelled peak(s) based on knowing their location and magnitude.

In one other aspect of the present disclosure, if the signal peak reduction performed at the transmitting device also involves additional kernel(s), such as kernel-2, the peak regeneration performed by the receiving device may also take the ratio (e.g., a) applied to kernel-1 into consideration if the value of α is known by the receiving device, such as through signaling from the transmitting device. For example, after observing and determining the peak difference (e.g.,2108) of a peak between z(t) and x(t), in restoring the peak, the receiving device may multiply the ratio α to the peak different (e.g., a is multiplied to the difference2108).

In another aspect of the present disclosure, based on knowing the location of the peak(s) cancelled by kernel-1, the receiving device may also determine that the peak cancellation or reduction performed by kernel-2 is likely to occur at same peak location(s). In other words, the transmitting device may assume that peak(s) cancelled/reduced by signal generated from kernel-1 is also cancelled/reduced by signal generated from kernel-2. Thus,

Once a cancelled peak is identified, the receiving device may compensate for kernel-2 (e.g., regenerate the peak cancelled by kernel-2) at the identified location. The receiving device may restore the peaks circularly using the circular shift concept described above, such that a signal with regenerated cancelled peak(s) (e.g., signal xnew) may be represented by:

To keep track of the cancelled peaks, the receiving device may construct an auxiliary signal xaux=x−|y(t0)|circhisft(p*, t0) where p* may be an “ideal” kernel, such as described in connection withFIG.15.

FIG.22is a diagram2200illustrating an example of regenerated signal (e.g., xnew) at a receiving device. As described above, by observing the waveform2206of x(t) and waveform2208of z(t), the location and magnitude for peaks cancelled at the transmitting device may be identified. Then the receiving device may compensate the received signal z(t) by regenerating the cancelled peaks in z(t) to construct the waveform2204(e.g., xnew), which is closer to the waveform2202of the original signal (e.g., signal before peak reduction) than the received waveforms2208z(t). Thus, the distortion and/or EVM produced during the signal peak cancellation process at the transmitting device may be mitigated.

FIG.23is a diagram2300illustrating an example of signal regeneration at a receiving device (e.g., base station102,180,310, etc.). At2302, the receiving device may receive a signal in frequency domain (e.g., Z(f)) including reserved tones Y(f) and data tones X(f) from a transmitting device. The receiving device may first separate Y(f) from X(f), such as shown at2304and2306. At2308, the receiving device may convert frequency domain signal Y(f) to time domain signal y(t) by applying iFFT to the Y(f). At2310, the receiving device may identify one or more peaks cancelled at the transmitting device based on x(t) and y(t), such as described in connection withFIGS.22and23. Similarly, at2312, the receiving device may convert frequency domain signal X(f) to time domain signal x(t) by applying iFFT to the X(f). At2314, the transmitting device may perform peak regeneration (e.g., x(t)+p(t)), and a resulting signal s(t) (e.g., xnew) may be obtained, such as described in connection withFIGS.22and23. At2316, the receiving device may then convert the resulting time domain signal s(t) to frequency domain signal S(t) by applying FFT to the s(t).

Referring back to the example where a linear combination is applied to the kernel-1 and the kernel-2. In each iteration, znew=z−(|z(j)|−μ)(αpkernel1+(1−α)pkernel-2), the parameter α (e.g., 0≤α≤1) may determine how much each kernel contributes or the percentage of each kernel's contribution. For example, if α=0, then only kernel-1 may be contributing the peak cancelling signal; if α=1, then only kernel-2 may be contributing the peak cancelling signal; if α=0.4, then kernel-1 may be contributing 40% of the peak cancelling signal while kernel-2 may be contributing 60% of the peak cancelling signal, etc. As such, the value of α may also affect the performance of PAPR reduction when one or more kernel is used.

Aspects presented herein provide factors that may be considered by a transmitting device in determining the value of α. As when the value of α is approaching 0 (e.g., α≈0), such as 0.1, 0.2, etc., the contribution of kernel-2 approaches 1 (e.g., 100%), thereby most of the burden may be placed on kernel-2. As PRTs for kernel-2 (e.g.,1608ofFIG.16) overlaps with data tones (e.g.,1606ofFIG.16) either in full or in part, kernel-2 may distort the signal in the frequency domain, and may also introduce EVM to the transmission, such as described in connection withFIG.18. In one example, a transmitting device may select the value of α to be close to zero (e.g., 0.1-0.3) and place more burden (e.g., contribution) on kernel-2 when a target PAPR is unable to be achieved with kernel-1 alone because of the high side-lobes generated by kernel-1, such as the PAPR threshold described in connection withFIG.18. Thus, if the target of the transmitting device is to further lower the PAPR threshold, kernel-2 may be configured to provide more contribution than kernel-2. In another example, the transmitting device may select the value of α to be close to zero or have kernel-2 to provide more contribution than kernel-1 when there is a high Signal-to-Interference-plus-Noise Ratio (SINR) in the channel. When the receiving device is unable to decode PRTs in the reserved tones (e.g., y(t)), it may be difficult for the receiving device to perform peak regeneration for the received signal and compensate for the received signal, such as described in connection withFIGS.21to23. For example, when the receiving device is unable to decode y(t), the receiving device may not be able to determine x(t) from z(t). Without x(t), the receiving device may not be able to determine the location and magnitude of the cancelled peak(s). As the signal for reserved tones or PRTs located in reserved tones (e.g., y(t)) are weaker than data tones in general (e.g., x(t)), when there is a high SINR in the channel, more burden should be placed on kernel-2 (i.e., contribution of kernel-2 is higher than kernel-1). Note that the transmitting device may be a base station or a UE. Thus, when the receiving device is a base station, the receiving device may determine the value of α for the transmitting device, such as a UE.

On the other hand, in another aspect, when the value of α is approaching 1 (e.g., α≈1), such as 0.8, 0.9, etc., the contribution of kernel-1 approaches 1 (e.g., 100%), thereby most of the burden may be placed on kernel-1. While a signal generated from kernel-1 may not introduce EVM, the signal may have moderate to high side-lobes, such as described in connection withFIG.17. In one example, a transmitting device may select the value of α to be close to 1 (e.g., 0.1-0.3) and place more burden (e.g., contribution) on kernel-1 when there is a poor channel condition (e.g., high SINR) where the receiving device is unable to decode y(t) or learn anything from y(t). In another example, the transmitting device may select the value of α to be close to 1 when the number of available PRTs or reserved tones is high in kernel-1. When there are more options for allocating PRTs, better peak cancelling signal may be formed and lower target PAPR may be achieved, such as described in connection withFIGS.17and18. In other words, when the peak cancelling signal generated by kernel-1 is good or sufficient, the transmitting device may configure kernel-1 to provide higher contribution than kernel-2. In one other example, the transmitting device may select the value of α to be close to 1 when PRTs are to be shared by other UE(s) or when the PRTs between UE(s) overlap each other. For example, if two UEs are using same PRTs (e.g., PRT sequence) or there is at least an overlap between their PRTs, the base station may be unable to decode the y(t) as the y(t) may correspond to multiple users. Thus, more burden may be placed on kernel-1.

FIGS.24A,24B and24Care diagrams2400A,2400B and2400C illustrating example EVM for 256QAM, where target PAPR is 7 dB, α=0.5, numDataTones=240, numPRT=16. When only kernel-2 is used, as shown byFIG.24A, a lot distortion may be observed at the receiving device, where the receiving device may not be able to read or understand the constellation and decode the signal. The EVM may also be high (e.g., −22 dB). When both kernel-1 and kernel-2 are used and they are linearly combined with α=0.5 (e.g., each kernel contributes equally), as shown byFIG.24B, the constellation of the received signal may look better than the constellation inFIG.24A. As kernel-1 does not introduce any distortion (e.g., PRTs are located to reserved tones), by placing part of the burden (e.g., contribution) to kernel-1, the EVM of the received signal may be improved (e.g., −27 dB). Thus, the receiving device may be able to decode the received signal. When peak regeneration (e.g., described in connection withFIG.23) is further applied to the received signal, as shown byFIG.24C, the EVM may further be improved (e.g., −36 dB) as the regenerated signal more closely resembles the original signal (e.g., signal before applying peak cancellation by kernel-1 and kernel-2). The constellation of the signal overserved by the receiving device may look cleaner than ones shown inFIGS.24A and24B, and the receiving device may have higher success rate of decoding the received signal.

In some examples, a PRT table or a PRT set including one or more PRT sequences may be pre-defined and fixed at the transmitting device and the receiving device. For example, each PRT sequence in the PRT table or set may include a fixed number of PRTs at pre-fixed locations (e.g., fixed PRT pattern), and the number of PRTs and/or their locations may be different for each PRT sequence. There may also be overlaps between different PRT sequences. For example, one PRT sequence may have PRTs at tones 1, 2, 3, 5, 7, another PRT sequence may have PRTs at tones 1, 2, 4, 6, 7 (with some overlap), and another PRT sequence may have PRTs at tones 4, 6, 8, 9, 10 (without overlap), etc.FIG.25is a diagram2500illustrating an example of PRT table, where one or more sequence of PRTs may be pre-defined in the PRT table. Thus, a transmitting device may pick a sequence within the PRT table to locate PRTs.

In addition to specific-transmission based aspects, techniques also include receiver-specific features. For example, a receiving device (e.g., base station) to decode a transmission involving the tone reservation, the receiving device may be configured to determine which tones within a transmission are data tones and which tones are PRTs. This determination aids and/or enables a receiving device to ignore or bypass PRTs and decode data tones. In addition, the receiving device may also need to know whether the transmitting device is sending the transmission with the tone reservation in the first place, whether PRTs are allocated to data tones, whether peak regeneration is required and/or which PRT sequence is chosen by the transmitting device, etc.

Aspects presented here may enable a transmitting device to signaling the location of the reserved tones or PRTs to a receiving device. In one aspect, the location of the PRTs may be fixed in advance either in a PRT table (PRTT) or via a deterministic function such as a perfect ruler, a Golomb ruler, a Gold sequence, a Costas array and/or a linear function, such as described in connection withFIG.15and Table 1. Thus, the transmitting device, such as a base station, may signal (e.g., send indication to) the receiving device, such as a UE the appropriate row of the PRT table and/or the parameters of the deterministic function. For example, the base station may inform the UE which set of Golomb ruler to use for allocation of PRTs, and the UE may allocate PRTs according to the set chosen by the base station, such that the base station may know which tones to ignore (e.g., PRTs) and which tones to decode. The base station may send this information to the UE via DCI, MAC-CE and/or RRC, etc., and the base station may determine whether to use DCI, MAC-CE and/or RRC depending on how time sensitive is the communication. In addition, the UE may recover the PRT sequence from the PRT table if a PRT table is indicated to the UE by the base station. Thus, each entry of the PRT table may be the PRT sequence, or it may be parameters to a deterministic function that generates the PRT sequence, etc. Alternatively, or additionally, the signaling for PRT location may be explicit, where the base station may inform the UE(s) which tones should be used as PRT. For example, if any PRT related or tone reservation mechanism is used in the downlink, the base station may be configured to inform the UE of the parameters the base station has used. If the mechanism is used for the uplink, the base station may be configured to inform the UE which parameters to use. As mentioned previously, the transmitting device may be a base station or a UE and the receiving device may be a base station or a UE as well. Thus, examples using the base station and the UE are for illustration purposes, and shall not be construed to limit the scope of the present disclosure.

To assist a receiving device to restore cancelled peak(s) and regenerate the received signal, such as described in connection withFIGS.21-23, the transmitting device and the receiving device may need to have a consensus or the same knowledge on certain parameters. In one aspect, when one or more peak cancelling kernel (e.g., kernel-1 and kernel-2) is used, the transmitting device and the receiving device may agree the parameter for α, such as via explicit signaling or in a PRT table. In other aspect, the transmitting device and the receiving device may agree on the target PAPR, such as shown by the “expected target PAPR” inFIG.21. For example, the transmitting device may set an expected target PAPR, and the receiving device may receive a transmission z(t) with the signal falling below the expected target PAPR, such as shown by2102inFIG.21. The receiving device may then set y(t) to zero to obtain x(t), such as described in connection withFIGS.21-23, where the receiving device may observe one or more peak in x(t) exceeds the expected target PAPR. Thus, the receiving device may be able to identify the location of the one or more cancelled peak(s) based at least in part on the expected target PAPR. In one other aspect, the transmitting device, such as a UE, may need to know the permissible power spectral density (e.g., max power allowed) for each kernel (e.g., kernel-1 and kernel-2).

Aspects presented herein enable a transmitting device to multiplex different MCS for the one or more kernels (e.g., kernel-1 and kernel-2). In one aspect, tones corresponding to kernel-1 and kernel-2 may be overloaded with different Modulation and Coding Scheme (MCS).FIGS.26A and26Bare diagrams2600A and2600B illustrating example MCS for kernel-1 and kernel-2. InFIG.26A, a transmission may include a plurality of data tones (e.g., tone index 1-22) without reserved tones, such that the PRTs2608for kernel-1 and PRTs2606for kernel-2 are overlapped with data tones (e.g., kernel-1 is functioning similar to kernel-2). The transmitting device may apply a first MCS (e.g., 256-QAM data) on the data tones2604corresponding to the PRTs2606for kernel-2 (e.g., tone index 2-4, 7, 9, 13, 14, 17, 18, 19) and the transmitting device may apply a second MCS (e.g., QPSK) to the data tones2602corresponding to the PRTs2608for kernel-1 (e.g., tone index 1, 5, 6, 8, 10-12, 15, 16, 19, 21, 22). As one kernel in kernel-1 and kernel-2 may have a noise higher than the other one, the transmitting device may apply an MCS with lower modulation order (e.g., QPSK) to the kernel with higher noise level as MSC with lower modulation order may be more tolerable or susceptible to the noise. The transmitting device may then apply an MCS with higher modulation order (e.g., 256-QAM) to the kernel with lower noise level.

When a receiving device receives the transmission, the receiving device may first decode data tones2602that has lower modulation order, and then subtract data tones2602from the transmission. The transmission after subtracting data tones2604is shown byFIG.26B, where the allocation of data tones2604that has higher modulation order and PRTs2608for kernel-1 may resemble to the diagram700ofFIG.7. For example, the receiving device may observe a transmission that has PRTs (e.g.,2608) not overlapping with data tones (e.g.,2604). Based on the transmission shown inFIG.26B, the receiving device may identify the location and magnitude of the one or more peak cancelled at the transmitting device using PRTs2606for kernel-1, such as described in connection withFIGS.21-23. Based on the identified location and magnitude of the cancelled peak(s), the receiving device may regenerate the cancelled peak(s) to improve the SNR, such as described in connection withFIGS.21-23. Afterwards, the receiving device may decode the data tones2604with higher modulation order (e.g., 256-QAM). Although the example of QPSK and 256 QAM is provided to illustrate the concept of two MCSs applied to the different sets of data tones, the concepts described herein may also be applied for other MCS than QPSK and 256 QAM.

For example, let x(t) be the waveform corresponding to the high MCS data (e.g.,2604) and y(t) be the waveform corresponding to the low MCS data (e.g.,2602). Then the PRTs (e.g.,2608and2606) corresponding to the high MCS data and the low MCS data may be used to reduce the PAPR of x(t)+y(t). For instance, if the PRT waveform for kernel-1 and kernel-2 are s1(t) and s2(t) respectively, then the goal of the transmitting device is to make x(t)+y(t)+s1(t)+s2(t) to have a low PAPR. The tone reservation mechanism (e.g., PRT allocation) described in connection withFIGS.7-11and15-20may be applied to x(t)+y(t)+s1 (t)+s2(t) to achieve the goal. For example, let X(f), Y(f), S1(f) and S2(f) be the frequency-domain representation of x(t), y(t), s1(t) and s2(t). There may be no overlap between the tones in the support of X(f) and Y(f), where tones in the support of Y(f) and S2(f) fully overlap and tones in the support of X(f) and S1(f) fully overlap. In another aspect, when using two MCS, the transmitting device, such as a UE, may assign different transmission power to X(f) and Y(f). For instance, if the two MCS are equal, then the transmitting device may assign a higher transmission power to Y(f) to compensate for the noise introduced by kernel-2, such that the receiving device is able to differentiate X(f) and Y(f).

For a receiving device to decode the transmission involving two MCS, the receiving device may need to be informed that the transmitting device is transmitting the transmission using two MCS. In one example, when a base station is the receiving device, the base station may signal (e.g., send indication to) a transmitting device (e.g., the UE) regarding the one or more potential and different MCS to use for different subsets of the tones for a transmission. In another example, a first MCS may be signaled for the first subset of the data tones and a second MCS may be signaled for the second subset.

In order for a receiving device, such as a base station, to decode a transmission involving two MCS, the transmitting device, such as the UE, may attempt to limit noise that is introduced into the transmission (e.g., in the PRTs2606and2608). Otherwise the receiving device may not be able to decode the transmission. In one aspect, a power constraint may be applied to the transmission device for each set of tones. For example, a base station may apply one or more power constraints for each set of tones (e.g.,2606,2608) to a UE transmitting with two MCS. The UE may then follow the power constraints rule received for each set of tones that is to be transmitted to the base station. This may avoid significant distortion to the data (e.g.,2602and2604). The power constraint rule(s) may be inferred from the two MCS that are signaled to the UE, or it may be signaled separately (e.g., in a separate message or indication), or it may be fixed in advance in the UE, such as in the PRT table. In receiving the transmission, the base station may perform noise estimation for the data (e.g.,2602,2604) based at least in part on the assumption that the UE is using the PRTs for reducing the peaks of the signal while adhering to the required power constraint.

FIG.27illustrates an example communication flow2700between a transmitting device2702and a receiving device2704according to aspects of the present disclosure. For example, the aspects may be performed by a transmitter and receiver as discussed in connection withFIG.1or3. Various aspects may be optional. The transmitting device2702may be a UE or a base station, and the receiving device2704may also be a UE or a base station.

At2706, the transmitting device2702may construct a first PAPR reduction signal from a first set of PRTs within a plurality of tones, where the first set of PRTs may overlap with a first set of data tones, such as described in connection withFIG.26A.

At2708, the transmitting device2702may construct a second PAPR reduction signal from a second set of PRTs within the plurality of tones, where the second set of PRTs may overlap a second set of data tones. The first set of PRTs may not overlap with the second set of PRTs, and the first set of data tones may not overlap with the second set of data tones, such as described in connection withFIG.26A. In one example, at least one of the first set of PRTs or the second set of PRTs may be based, at least in part, on a Costas array, a Gold sequence, a Golomb ruler, or a truncated MLS.

At2710, the transmitting device2702may apply a first MCS to the first set of data tones and a second MCS to the second set of data tones, such as described in connection withFIG.26A. In one example, prior to apply different MCS to the first set of data tones and the second set of data tones, as shown at2709, the transmitting device2702may receive an indication from the receiving device2704to apply multiple MCS for different subsets of tones, where different MCS may be indicated for data tones and peak reduction tones, such as described in connection withFIGS.26A and26B. For example, the transmitting device2702may receive an indication from the base station to apply the first MCS for the first set of data tones and the second MCS for the second set of data tones.

At2712, the transmitting device2702may transmit a data transmission using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal, such as described in connection withFIG.26A. In one example, the transmitting device2702may transmit the data transmission on the first set of data tones with a first transmission power, and the transmitting device2702may transmit the data transmission on the second set of data tones with a second transmission power. In another example, the transmitting device2702may receive an indication from the receiving device2704regarding a power constraint for the first transmission power and the second transmission power. The power constraint may be indicated based on an MCS signaled to the transmitting device2702, and/or explicitly signaled to the transmitting device2702. Thus, the transmitting device2702may apply a fixed power constraint to the first transmission power and/or the second transmission power, such as described in connection withFIGS.26A and26B.

At2714, the receiving device2704may receive the data transmission from the transmitting device2702that includes the first set of tones based on the first MCS and the second set of tones based on the second MCS, where at least one signal peak of the data transmission may be reduced by a combination of the first PAPR reduction signal and the second PAPR reduction signal at the transmitting device2702. For example, as described at2706and2708, the first PAPR reduction signal may include the first set of PRTs that overlaps the first set of data tones and the second PAPR reduction signal may include the second set of PRTs that overlaps the second set of data tones, where the first set of data tones may not overlap with the second set of data tones, such as described in connection withFIGS.26A and26B. The allocation of the first set of PRTs or the second set of PRTs may be based, at least in part, on a Costas array, a Gold sequence, a Golomb ruler, or a truncated maximum length sequence.

At2716, the receiving device2704may decode the first set of data tones and cancel interference caused by the first set of data tones to the first set of peak reduction tones, such as described in connection withFIGS.26A and26B. In decoding the data transmission based on a respective kernel, the receiving device2704may determine one or more of a location, a phase, and a magnitude of the respective kernel. In addition, decoding the data transmission based on the respective kernel may further include regenerating the data transmission prior to application of the respective kernel by adding the kernel to the received data transmission.

In one example, the receiving device2704may identify a location, a magnitude and a phase of the at least one signal peak of the data transmission that is reduced based on a location of the second set of PRTs and regenerate at least a portion of the at least one signal peak of the data transmission that is reduced based at least in part on the identified location, magnitude and phase of the at least one signal peak of the data transmission that is reduced, such as described in connection withFIGS.21-23. The regeneration of the at least one signal peak of the data transmission may increase the SNR of the data transmission.

FIG.28illustrates a flowchart of a method2800of wireless communication. The method may be performed by a transmitting device or a component of a transmitting device (e.g., the transmitting device2702; the apparatus2902; a processing system, which may include the memory360and which may be the entire UE350or a component of the UE350, such as the TX processor368, the RX processor356, and/or the controller/processor359). In some aspects, the method may be performed by a transmitting device such as described in connection with any ofFIG.1,3, or27. One or more aspects illustrated inFIG.28may be optional. Various implementations may include a method with any combination of the aspects described in connection withFIG.28. The method may enable the transmitting device to multiplex different sets of data tones with different MCS and reduce the PAPR for different sets of data tones.

At2802, the transmitting device may apply a first MCS to a first set of data tones that overlaps with a first set of PRTs within a plurality of tones, the first set of PRTs being associated with a first PAPR reduction signal, such as described in connection withFIGS.26A and27. For example, at2706, the transmitting device2702may generate a first PAPR reduction signal from a first set of PRTs within a plurality of tones, where the first set of PRTs may overlap with a first set of data tones, and at2710, the transmitting device2702may apply the first MCS to the first set of data tones. The application of the first MCS may be performed, e.g., by the first kernel component2940, the MCS component2944, and/or the second kernel component2942of the apparatus2902inFIG.29.

At2804, the transmitting device may apply a second MCS to a second set of data tones that overlaps with a second set of PRTs within the plurality of tones, the second set of PRTs being associated with a second PAPR reduction signal, such as described in connection withFIGS.26A and27. For example, at2708, the transmitting device2702may generate a second PAPR reduction signal from a second set of PRTs within the plurality of tones, where the second set of PRTs overlaps a second set data tones, where the first set of PRTs does not overlap with the second set of PRTs, and the first set of data tones does not overlap with the second set of data tones, and at2710, the transmitting device2702may apply the second MCS to the second set of data tones.

The application of the second MCS may be performed, e.g., by the first kernel component2940, the second kernel component2942, and/or the MCS component2944of the apparatus2902inFIG.29. In an example, at least one of the first set of PRTs or the second set of PRTs are based, at least in part, on a Costas array, a Gold sequence, a Golomb ruler, or a truncated MLS.

In one example, prior to apply the data with different MCS, the transmitting device may receive an indication from a receiving device (e.g., a base station) to apply multiple MCS for different subsets of tones, where different MCS may be indicated for data tones and peak reduction tones, such as described in connection withFIGS.26A,26B and27. For example, the transmitting device may receive an indication from the receiving device to apply the first MCS for the first set of data tones and the second MCS for the second set of data tones.

At2806, the transmitting device may transmit a transmission signal comprising the first set of data tones and the second set of data tones, the transmission signal using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal, such as described in connection withFIGS.26A and27. For example, at2712, the transmitting device2702may transmit a data transmission to the receiving device2704using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal. The transmission of the data transmission using the waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal may be performed, e.g., by the PAPR reduction signal process component2946and/or the transmission component2934of the apparatus2902inFIG.29. In one example, the transmitting device may transmit the transmission signal on the first set of data tones with a first transmission power, and the transmitting device may transmit the transmission signal on the second set of data tones with a second transmission power. The transmitting device may receive an indication from the receiving device regarding a power constraint for the first transmission power and the second transmission power. The power constraint may be indicated based on an MCS signaled to the transmitting device, and/or explicitly signaled to the transmitting device. Thus, the transmitting device may apply a fixed power constraint to the first transmission power and/or the second transmission power, such as described in connection withFIGS.26A and26B.

FIG.29is a diagram2900illustrating an example of a hardware implementation for an apparatus2902. The apparatus2902may be a transmitting device (e.g., the transmitting device2702). In some aspects, the apparatus2902may be a UE (e.g., as described in connection with the UE104or350inFIGS.1and/or3), a component of a UE, or may implement UE functionality. In other aspects, the apparatus2902may be a base station (e.g., as described in connection with the base station102/180or310inFIG.1and/orFIG.3), a component of a base station, or may implement base station functionality. In some aspects, the apparatus2902may include a cellular baseband processor2904(also referred to as a modem) that may be coupled to a cellular RF transceiver2922. In some scenarios, the apparatus2902may further include one or more subscriber identity modules (SIM) cards2920, an application processor2906coupled to a secure digital (SD) card2908and a screen2910, a Bluetooth® module2912, a wireless local area network (WLAN) module2914, a Global Positioning System (GPS) module2916, and/or a power supply2918. The cellular baseband processor2904communicates through the cellular RF transceiver2922with a receiving device, e.g., which may be the UE104and/or BS102/180. The cellular baseband processor2904may include a computer-readable medium/memory. The cellular baseband processor2904is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the cellular baseband processor2904, causes the cellular baseband processor2904to perform the various functions described herein. The computer-readable medium/memory may also be used for storing data that is manipulated by the cellular baseband processor2904when executing software. The cellular baseband processor2904further includes a reception component2930, a communication manager2932, and a transmission component2934. The communication manager2932includes the one or more illustrated components. The components within the communication manager2932may be stored in the computer-readable medium/memory and/or configured as hardware within the cellular baseband processor2904. The cellular baseband processor2904may be a component of the UE350and may include the memory360and/or at least one of the TX processor368, the RX processor356, and the controller/processor359. In one configuration, the apparatus2902may be a modem chip and include just the baseband processor2904, and in another configuration, the apparatus2902may be the entire UE (e.g., see350ofFIG.3) and include the additional modules of the apparatus2902. In other aspects, the cellular baseband processor2904may be a component of the base station310or the entire base station310and may include the additional modules of the apparatus2902.

The communication manager2932includes a first kernel component2940that is configured to apply a first MCS to a first set of data tones that overlaps with a first set of PRTs within a plurality of tones, the first set of PRTs being associated with a first PAPR reduction signal, e.g., as described in connection with2802ofFIG.28. The communication manager2932further includes a second kernel component2942that is configured to apply a second MCS to a second set of data tones that overlaps with a second set of PRTs within the plurality of tones, the second set of PRTs being associated with a second PAPR reduction signal, e.g., as described in connection with2804ofFIG.28. The communication manager2932further includes an MCS component2944that is configured to apply a first MCS to the first set of data tones and a second MCS to the second set of data tones, e.g., as described in connection with2802and/or2804ofFIG.28. The communication manager2932further includes a PAPR reduction signal process component2946that is configured to transmit a transmission signal comprising the first set of data tones and the second set of data tones, the transmission signal using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal, e.g., as described in connection with2806ofFIG.28.

As shown, the apparatus2902may include a variety of components configured for various functions. In one configuration, the apparatus2902, and in particular the cellular baseband processor2904, includes means for applying a first MCS to a first set of data tones that overlaps with a first set of PRTs within a plurality of tones, the first set of PRTs being associated with a first PAPR reduction signal (e.g., the first kernel component2940and/or the MCS component2944). The apparatus2902may further include means for applying a second MCS to a second set of data tones that overlaps with a second set of PRTs within the plurality of tones, the second set of PRTs being associated with a second PAPR reduction signal (e.g., the second kernel component2942and/or the MCS component2944). The apparatus2902may further include means for transmit a transmission signal comprising the first set of data tones and the second set of data tones, the transmission signal using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal (e.g., the PAPR reduction signal process component2946and/or the transmission component2934).

The means may be one or more of the components of the apparatus2902configured to perform the functions recited by the means. As described herein, the apparatus2902may include the TX Processor368, the RX Processor356, and the controller/processor359. As such, in one configuration, the means may be the TX Processor368, the RX Processor356, and the controller/processor359configured to perform the functions recited by the means.

FIG.30is a flowchart3000of a method of wireless communication. The method may be performed by a receiving device or a component of a receiving device (e.g., the receiving device2704; the apparatus3102; which may include the memory376and which may be the entire base station310or a component of the base station310, such as the TX processor316, the RX processor370, and/or the controller/processor375). In some aspects, the method may be performed by a base station or a component of a base station (e.g., base station102,180,310). In other aspects, the method may be performed by a UE or a component of a UE (e.g., UE104,350). In some aspects, the method may be performed by a receiving device such as described in connection with any ofFIG.1,3, or27. One or more aspects illustrated inFIG.30may be optional. Various implementations may include a method with any combination of the aspects described in connection withFIG.30. The method may enable the receiving device (e.g., a base station) to receive a data transmission with multiple sets of data tones from a transmitting device (e.g., a UE), where each set of data tones has different MCS or MCS with different modulation order. The receiving device may decode one set of data tone using one MCS, and then decode another set of data tone using another MCS.

At3002, the receiving device may receive a data transmission from a transmitter having a first set of tones based on a first MCS and a second set of tones based on a second MCS, where at least one signal peak of the data transmission is reduced by a combination of a first PAPR reduction signal and a second PAPR reduction signal at the transmitter, where the first PAPR reduction signal comprises a first set of PRTs that overlaps a first set of data tones and the second PAPR reduction signal comprises a second set of PRTs that overlaps a second set of data tones, where the first set of data tones does not overlap with the second set of data tones, such as described in connection withFIGS.26A,26B and27. For example, at2714, the receiving device2704may receive a data transmission from the transmitting device2702that may have the first set of tones based on the first MCS and the second set of tones based on a second MCS, where at least one signal peak of the data transmission is reduced by a combination of a first PAPR reduction signal and a second PAPR reduction signal at the transmitter, and the first PAPR reduction signal may include the first set of PRTs that may overlap the first set of data tones and the second PAPR reduction signal may include the second set of PRTs that may overlap the second set of data tones, and the first set of data tones does not overlap with the second set of data tones. The reception of the data transmission may be performed, e.g., by the data reception process component3140and/or the reception component3130of the apparatus3102inFIG.31. The allocation of the first set of PRTs or the second set of PRTs may be based, at least in part, on a Costas array, a Gold sequence, a Golomb ruler, or a truncated maximum length sequence.

Prior to receive the data transmission with different MCS, the receiving device may transmit an indication to a UE informing the UE to transmit the transmission with multiple MCS for different subsets of tones, where different MCS may be indicated for data tones and peak reduction tones. In addition, the receiving device may also indicate a power constraint to the UE, where the receiving device may indicate to the UE to apply a fixed power constraint to data tones, where different power constraint may be applied to different set of data tones. The receiving device may indicate the power constraint based on an MCS signaled to the UE or the receiving device may explicitly signal the power constraint to the UE. In response, the receiving device may receive the data transmission on the first set of tones based on a first transmission power, and the receiving device may receive the data transmission on the second set of tones based on a second transmission power. In one other aspect, the receiving device may perform noise estimation for a portion of the data transmission based on UE using peak reduction tones to reduce peaks of the signal and based on the UE adhering to a power constraint.

At3004, the receiving device may decode the first set of data tones and cancel interference caused by the first set of data tones to the first set of peak reduction tones, such as described in connection withFIGS.26A,26B, and27. For example, at2716, the receiving device2704may decode the first set of data tones and cancel interference caused by the first set of data tones to the first set of peak reduction tones. The decoding of the data tone may be performed, e.g., by the decoder component3142of the apparatus3102inFIG.31.

In one example, in decoding the data transmission based on a respective kernel, the receiving device may determine one or more of a location, a phase, and a magnitude of the respective kernel. In addition, decoding the data transmission based on the respective kernel may further include regenerating the data transmission prior to application of the respective kernel by adding the kernel to the received data transmission. For example, as shown at3006, the receiving device may identify a location, a magnitude and a phase of the at least one signal peak of the data transmission that is reduced based on a location of the second set of PRTs and regenerate at least a portion of the at least one signal peak of the data transmission that is reduced based at least in part on the identified location, magnitude and phase of the at least one signal peak of the data transmission that is reduced, such as described in connection withFIGS.21-23. The identification of the location, the magnitude and the phase of the at least one signal peak of the data transmission may be performed, e.g., by the identification component3144of the apparatus3102inFIG.31. The regeneration of the at least one signal peak of the data transmission may increase the SNR of the data transmission.

FIG.31is a diagram3100illustrating an example of a hardware implementation for an apparatus3102. The apparatus may correspond to the receiving device3004described in connection withFIG.30, for example. In some aspects, the apparatus3102may be a base station, (e.g., as described in connection with the base station102,180, or310inFIG.1orFIG.3), a component of a base station, or may implement base station functionality. In other aspects, the apparatus may be a UE (e.g., UE104or350as described in connection withFIG.1orFIG.3), a component of a UE, or may implement UE functionality. The apparatus may include a baseband unit3104. The baseband unit3104may communicate through a cellular RF transceiver with a transmitting device. In some aspects, the apparatus3102may be a base station and the transmitting device may be a UE, e.g., UE104. In other aspects, the apparatus3102may be a UE and the transmitting device may be a base station. The baseband unit3104may include a computer-readable medium/memory. The baseband unit3104is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the baseband unit3104, causes the baseband unit3104to perform the various functions described herein. The computer-readable medium/memory may also be used for storing data that is manipulated by the baseband unit3104when executing software. The baseband unit3104further includes a reception component3130, a communication manager3132, and a transmission component3134. The communication manager3132includes the one or more illustrated components. The components within the communication manager3132may be stored in the computer-readable medium/memory and/or configured as hardware within the baseband unit3104. The baseband unit3104may be a component of the BS310and may include the memory376and/or at least one of the TX processor316, the RX processor370, and the controller/processor375.

The communication manager3132includes a data reception process component3140that is configured to receive a data transmission from a transmitter having a first set of tones based on a first MCS and a second set of tones based on a second MCS, where at least one signal peak of the data transmission is reduced by a combination of a first PAPR reduction signal and a second PAPR reduction signal at the transmitter, where the first PAPR reduction signal comprises a first set of PRTs that overlaps a first set of data tones and the second PAPR reduction signal comprises a second set of PRTs that overlaps a second set of data tones, where the first set of data tones does not overlap with the second set of data tones, e.g., as described in connection with3002ofFIG.30. The communication manager3132further includes a decoder component3142that is configured to decode the first set of data tones and cancel interference caused by the first set of data tones to the first set of peak reduction tones, e.g., as described in connection with3004ofFIG.30. The communication manager3132further includes an identification component3144that is configured to identify a location, a magnitude and a phase of the at least one signal peak of the data transmission that is reduced based on a location of the second set of PRTs and regenerate at least a portion of the at least one signal peak of the data transmission that is reduced based at least in part on the identified location, magnitude and phase of the at least one signal peak of the data transmission that is reduced, e.g., as described in connection with3006ofFIG.30.

As shown, the apparatus3102may include a variety of components configured for various functions. In one configuration, the apparatus3102, and in particular the baseband unit3104, includes means for receiving a data transmission from a transmitter having a first set of tones based on a first MCS and a second set of tones based on a second MCS, where at least one signal peak of the data transmission is reduced by a combination of a first PAPR reduction signal and a second PAPR reduction signal at the transmitter, where the first PAPR reduction signal comprises a first set of PRTs that overlaps a first set of data tones and the second PAPR reduction signal comprises a second set of PRTs that overlaps a second set of data tones, where the first set of data tones does not overlap with the second set of data tones (e.g., the data reception process component3140and/or the reception component3130). The apparatus3102may further include means for decoding the first set of data tones and canceling interference caused by the first set of data tones to the first set of peak reduction tones. The apparatus3102may further include means for identifying a location, a magnitude and a phase of the at least one signal peak of the data transmission that is reduced based on a location of the second set of PRTs, and means for regenerating at least a portion of the at least one signal peak of the data transmission that is reduced based at least in part on the identified location, magnitude and phase of the at least one signal peak of the data transmission that is reduced (e.g., the identification component3144and/or the reception component3130).

The means may be one or more of the components of the apparatus3102configured to perform the functions recited by the means. As described herein, the apparatus3102may include the TX Processor316, the RX Processor370, and the controller/processor375. As such, in one configuration, the means may be the TX Processor316, the RX Processor370, and the controller/processor375configured to perform the functions recited by the means.

FIG.32illustrates a flowchart of a method3200of wireless communication. The method may be performed by a transmitting device or a component of a transmitting device (e.g., the apparatus3302; a processing system, which may include the memory360and which may be the entire UE350or a component of the UE350, such as the TX processor368, the RX processor356, and/or the controller/processor359). In some aspects, the method may be performed by a transmitting device such as described in connection with any ofFIG.1,3, or27. One or more aspects illustrated inFIG.32may be optional. Various implementations may include a method with any combination of the aspects described in connection withFIG.32. The method may enable the transmitting device to allocate one or more PRT based on a sequence selected from a Golomb ruler or a perfect ruler. The transmitting device may then reduce the PAPR of a transmission by using the signal generated from the one or more PRT to cancel one or more signal peak within the transmission.

At3202, the transmitting device may determine a sequence that including a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence, such as described in connection with Table 1 andFIG.15. The determination of the sequence may be performed, e.g., by the PRT sequence determination component3340of the apparatus3302inFIG.33.

In one example, the set of integers within the sequence may form a closed interval. In another example, the transmitting device may apply an offset to each integer within the set of integers and select the location of the one or more PRT among the plurality of tones based on the set of integers with the offset. In another example, the sequence may be based on an optimal Golomb ruler, and the order of the optimal Golomb ruler may be determined based at least in part on a Ruzsa construction, such as described in connection with Table 1. For example, by applying the Ruzsa construction, the transmitting device may determine an order of the sequence based on a square root of a number of allocated tones (e.g., total tones). The transmitting device may then round the square root of the number to a closest whole number, and the transmitting device may optionally add a constant to the whole number. The whole number or the whole number with constant may correspond to the total number of integers within the sequence (e.g., order # of Table 1). In another example, to determine the sequence, the transmitting device may determine an optimal Golomb ruler based on the order of the sequence, and then determines PRT indices based on the marks on the optimal Golomb ruler. The transmitting device may optionally apply an offset to the integers within the order of the sequence prior to determine the PRT indices, such as described in connection with Table 1.

At3204, the transmitting device may select a location of one or more PRT among a plurality of tones for a data transmission based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones, such as described in connection with Table 1 andFIG.15. The selection of the location of the one or more PRT may be performed, e.g., by the PRT location selection component3342of the apparatus3302inFIG.33. For example, each integer within the sequence may correspond to one location for one of the one or more PRT within the plurality of tones, such as described in connection with Table 1. In addition, the plurality of tones may include one or more data tone, where the one or more PRT is selected to be ignored by the receiver (e.g., the base station) and the one or more data tone is transmitted to be decoded by the receiver.

At3206, the transmitting device may send the data transmission to a receiver (e.g., a base station), where a PAPR for the data transmission is reduced by the one or more PRT, such as described in connection withFIGS.7-11. The transmission of the data transmission with PAPR reduced may be performed, e.g., by the PAPR reduction component3344and/or the transmission component3334of the apparatus3302inFIG.33. The data transmission may include one or more resource blocks within an OFDM symbol.

FIG.33is a diagram3300illustrating an example of a hardware implementation for an apparatus3302. The apparatus3302may be a transmitting device. In some aspects, the apparatus3302may be a UE (e.g., as described in connection with the UE104or350inFIGS.1and/or3), a component of a UE, or may implement UE functionality. In other aspects, the apparatus3302may be a base station (e.g., as described in connection with the base station102/180or310inFIG.1and/orFIG.3), a component of a base station, or may implement base station functionality. The apparatus3302may include a cellular baseband processor3304(also referred to as a modem) that may be coupled to a cellular RF transceiver3322. In some scenarios, the apparatus3302may further include one or more subscriber identity modules (SIM) cards3320, an application processor3306coupled to a secure digital (SD) card3308and a screen3310, a Bluetooth® module3312, a wireless local area network (WLAN) module3314, a Global Positioning System (GPS) module3316, and/or a power supply3318. The cellular baseband processor3304communicates through the cellular RF transceiver3322with a receiving device, e.g., which may be the UE104and/or BS102/180. The cellular baseband processor3304may include a computer-readable medium/memory. The cellular baseband processor3304is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the cellular baseband processor3304, causes the cellular baseband processor3304to perform the various functions described herein. The computer-readable medium/memory may also be used for storing data that is manipulated by the cellular baseband processor3304when executing software. The cellular baseband processor3304further includes a reception component3330, a communication manager3332, and a transmission component3334. The communication manager3332includes the one or more illustrated components. The components within the communication manager3332may be stored in the computer-readable medium/memory and/or configured as hardware within the cellular baseband processor3304. The cellular baseband processor3304may be a component of the UE350and may include the memory360and/or at least one of the TX processor368, the RX processor356, and the controller/processor359. In one configuration, the apparatus3302may be a modem chip and include just the baseband processor3304, and in another configuration, the apparatus3302may be the entire UE (e.g., see350ofFIG.3) and include the additional modules of the apparatus3302. In other aspects, the cellular baseband processor3304may be a component of the base station310or the entire base station310and may include the additional modules of the apparatus3302.

The communication manager3332includes a PRT sequence determination component3340that is configured to determine a sequence that including a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence, e.g., as described in connection with3202ofFIG.32. The communication manager3332further includes a PRT location selection component3342that is configured to select a location of one or more PRT among a plurality of tones for a data transmission based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones, e.g., as described in connection with3204ofFIG.32. The communication manager3332further includes a PAPR reduction component3344that is configured to send the data transmission to a receiver, where a PAPR for the data transmission is reduced by the one or more PRT, e.g., as described in connection with3206ofFIG.32.

As shown, the apparatus3302may include a variety of components configured for various functions. In one configuration, the apparatus3302, and in particular the cellular baseband processor3304, includes means for determining a sequence that including a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence (e.g., the PRT sequence determination component3340). The apparatus3302may further include means for selecting a location of one or more PRT among a plurality of tones for a data transmission based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones (e.g., the PRT location selection component3342). The apparatus3302may further include means for sending the data transmission to a receiver, where a PAPR for the data transmission is reduced by the one or more PRT (e.g., the PAPR reduction component3344and/or the transmission component3334).

The means may be one or more of the components of the apparatus3302configured to perform the functions recited by the means. As described herein, the apparatus3302may include the TX Processor368, the RX Processor356, and the controller/processor359. As such, in one configuration, the means may be the TX Processor368, the RX Processor356, and the controller/processor359configured to perform the functions recited by the means.

FIG.34is a flowchart3400of a method of wireless communication. The method may be performed by a receiving device or a component of a receiving device (e.g., the apparatus3502; which may include the memory376and which may be the entire base station310or a component of the base station310, such as the TX processor316, the RX processor370, and/or the controller/processor375). In some aspects, the method may be performed by a base station or a component of a base station (e.g., base station102,180,310). In other aspects, the method may be performed by a UE or a component of a UE (e.g., UE104,350). In some aspects, the method may be performed by a receiving device such as described in connection with any ofFIG.1,3, or27. One or more aspects illustrated inFIG.34may be optional. Various implementations may include a method with any combination of the aspects described in connection withFIG.34. The method may enable the receiving device to indicate to the UE whether to send a transmission using tone reservation and/or which sequence should be used for allocation one or more PRTs. The method may also enable the receiving device to determine which tones may be PRTs and ignore the PRTs.

At3402, the receiving device may determine a sequence that includes a set of integers, where each integer within the sequence may be distinct and a difference between any pair of integers within the sequence may be distinct from other pairs of integers within the sequence, such as described in connection with Table 1 andFIG.15. The determination of the sequence may be performed, e.g., by the sequence determination component3540of the apparatus3502inFIG.35. In one example, the set of integers within the sequence may form a closed interval. In another example, the sequence may be based on an optimal Golomb ruler, and the order of the optimal Golomb ruler may be determined based at least in part on a Ruzsa construction, such as described in connection with Table 1. For example, by applying the Ruzsa construction, the receiving device may determine an order of the sequence based on a square root of a number of allocated tones (e.g., total tones). The receiving device may then round the square root of the number to a closest whole number, and the receiving device may optionally add a constant to the whole number. The whole number or the whole number with constant may correspond to the total number of integers within the sequence (e.g., order # of Table 1). In one other aspect, to determine the sequence, the receiving device may determine an optimal Golomb ruler based on the order of the sequence, and then determines PRT indices based on the marks on the optimal Golomb ruler. The receiving device may optionally apply an offset to the integers within the order of the sequence prior to determine the PRT indices, such as described in connection with Table 1.

At3404, the receiving device may receive a data transmission from a transmitting device, where the data transmission may include a plurality of tones, such as described in connection with Table 1 andFIG.15. The reception of the data transmission that includes a plurality of tones may be performed, e.g., by the tone process component3542and/or the reception component3530of the apparatus3502inFIG.35. Prior to receive the data transmission, the receiving device may transmit an indication to the transmitting device to send the data transmission with one or more PRT using a method or sequence specified by the receiving device.

At3406, the receiving device may identify a location of one or more PRT among the plurality of tones based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones, such as described in connection with Table 1 andFIG.15. The identification of the data transmission that includes a plurality of tones may be performed, e.g., by the PRT location identification component3544of the apparatus3502inFIG.35. In one example, each integer within the sequence may correspond to one location for one of the one or more PRT within the plurality of tones. In another example, the receiving device may apply an offset to each integer within the set of integers and select the location of the one or more PRT among the plurality of tones based on the set of integers with the offset.

At3408, the receiving device may ignore the one or more PRT when decoding the data transmission, such as described in connection withFIGS.7-11. The decoding of the data transmission may be performed, e.g., by the decoder component3546of the apparatus3502inFIG.35. When decoding the data transmission, the receiving device may decode one or more data tones within the plurality of tones. In addition, the data transmission may include one or more resource blocks within an OFDM symbol.

FIG.35is a diagram3500illustrating an example of a hardware implementation for an apparatus3502. In some aspects, the apparatus3502may be a base station (e.g., as described in connection with the base station102,180, or310inFIG.1orFIG.3), a component of base station, or may implement base station functionality. In other aspects, the apparatus may be a UE (e.g., UE104or350as described in connection withFIG.1orFIG.3), a component of a UE, or may implement UE functionality. The apparatus may include a baseband unit3504. The baseband unit3504may communicate through a cellular RF transceiver with a transmitting device. In some aspects, the apparatus3502may be a base station and the transmitting device may be a UE, e.g., UE104. In other aspects, the apparatus3502may be a UE and the transmitting device may be a base station. The baseband unit3504may include a computer-readable medium/memory. The baseband unit3504is responsible for general processing, including the execution of software stored on the computer-readable medium/memory. The software, when executed by the baseband unit3504, causes the baseband unit3504to perform the various functions described herein. The computer-readable medium/memory may also be used for storing data that is manipulated by the baseband unit3504when executing software. The baseband unit3504further includes a reception component3530, a communication manager3532, and a transmission component3534. The communication manager3532includes the one or more illustrated components. The components within the communication manager3532may be stored in the computer-readable medium/memory and/or configured as hardware within the baseband unit3504. The baseband unit3504may be a component of the BS310and may include the memory376and/or at least one of the TX processor316, the RX processor370, and the controller/processor375.

The communication manager3532includes a sequence determination component3540that determines a sequence that includes a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence, e.g., as described in connection with3402ofFIG.34. The communication manager3532further includes a tone process component3542that receives a data transmission from a transmitting device, where the data transmission includes a plurality of tones, e.g., as described in connection with3404ofFIG.34. The communication manager3532further includes a PRT location identification component3544that identifies a location of one or more PRT among the plurality of tones based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones, e.g., as described in connection with3406ofFIG.34. The communication manager3532further includes a decoder component3546that ignores the one or more PRT when decoding the data transmission, e.g., as described in connection with3408ofFIG.34.

As shown, the apparatus3502may include a variety of components configured for various functions. In one configuration, the apparatus3502, and in particular the baseband unit3504, includes means for determining a sequence that includes a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence (e.g., the sequence determination component3540). The apparatus3502may further include means for receiving a data transmission from a transmitting device, where the data transmission includes a plurality of tones (e.g., tone process component3542and/or the reception component3530). The apparatus3502may further include means for identifying a location of one or more PRT among the plurality of tones based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones (e.g., the PRT location identification component3544). The apparatus3502may further include means for ignore the one or more PRT when decoding the data transmission (e.g., the decoder component3546).

The means may be one or more of the components of the apparatus3502configured to perform the functions recited by the means. As described herein, the apparatus3502may include the TX Processor316, the RX Processor370, and the controller/processor375. As such, in one configuration, the means may be the TX Processor316, the RX Processor370, and the controller/processor375configured to perform the functions recited by the means.

Aspect 1 is a method of wireless communication at a transmitting device, including: applying a first MCS to a first set of data tones that overlaps with a first set of PRTs within a plurality of tones, the first set of PRTs being associated with a first PAPR reduction signal; applying a second MCS to a second set of data tones that overlaps with a second set of PRTs within the plurality of tones, the second set of PRTs being associated with a second PAPR reduction signal; and transmit a transmission signal comprising the first set of data tones and the second set of data tones, the transmission signal using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal.

In aspect 2, the method of aspect 1 further includes that at least one of the first set of PRTs or the second set of PRTs are based, at least in part, on a Costas array, a Gold sequence, a Golomb ruler, or a truncated maximum length sequence.

In aspect 3, the method of aspect 1 or aspect 2 further includes that transmitting the transmission signal includes: transmitting the transmission signal on the first set of data tones with a first transmission power; and transmitting the transmission signal on the second set of data tones with a second transmission power.

In aspect 4, the method of any of aspects 1-3 further includes that the transmitting device is a base station, the method further includes: indicating to a UE multiple MCS for the first set of data tones and the second set of data tones.

In aspect 5, the method of any of aspects 1-4 further includes that the base station indicates the first MCS for the first set of data tones and the second MCS for the second set of data tones.

In aspect 6, the method of any of aspects 1-5 further includes that when the transmitting device is a UE, the method further includes: receiving, from a base station, an indication of multiple MCS for different subsets of tones.

In aspect 7, the method of any of aspects 1-6 further includes that the UE receives the indication of the first MCS for the first set of data tones and the second MCS for the second set of data tones.

In aspect 8, the method of any of aspects 1-7 further includes that when the transmitting device is a base station, the method further including: indicating to a UE a power constraint.

In aspect 9, the method of any of aspects 1-8 further includes that the power constraint is indicated based on an MCS signaled to the UE.

In aspect 10, the method of any of aspects 1-9 further includes that the power constraint is explicitly signaled to the UE.

In aspect 11, the method of any of aspects 1-10 further includes that the transmitting device is a UE, and where the UE applies a fixed power constraint

In aspect 12, the method of any of aspects 1-11 further includes that when the transmitting device is a UE, the method further includes: receiving an indication of a power constraint from a base station.

In aspect 13, the method of any of aspects 1-12 further includes that the power constraint is indicated based on an MCS signaled to the UE.

In aspect 14, the method of any of aspects 1-13 further includes that the power constraint is explicitly signaled to the UE.

Aspect 15 is an apparatus for wireless communication including at least one processor coupled to a memory and configured to implement a method as in any of aspects 1 to 14.

Aspect 16 is an apparatus for wireless communication including means for implementing a method as in any of aspects 1 to 14.

Aspect 18 is a method of wireless communication at a receiving device, including: receiving a data transmission from a transmitter having a first set of tones based on a first MCS and a second set of tones based on a second MCS, where at least one signal peak of the data transmission is reduced by a combination of a first PAPR reduction signal and a second PAPR reduction signal at the transmitter, where the first PAPR reduction signal includes a first set of PRTs that overlaps a first set of data tones and the second PAPR reduction signal includes a second set of PRTs that overlaps a second set of data tones, where the first set of data tones does not overlap with the second set of data tones; and decoding the first set of data tones and canceling interference caused by the first set of data tones to the first set of peak reduction tones.

In aspect 19, the method of aspect 18 further includes: identifying a location, a magnitude and a phase of the at least one signal peak of the data transmission that is reduced based on a location of the second set of PRTs; and regenerating at least a portion of the at least one signal peak of the data transmission that is reduced based at least in part on the identified location, magnitude and phase of the at least one signal peak of the data transmission that is reduced.

In aspect 20, the method of aspect 18 or aspect 19 further includes that the regeneration of the at least one signal peak of the data transmission increases the SNR of the data transmission.

In aspect 21, the method of any of aspects 18-20 further includes that at least one of the first set of PRTs or the second set of PRTs are based, at least in part, on a Costas array, a Gold sequence, a Golomb ruler, or a truncated MLS.

In aspect 22, the method of any of aspects 18-21 further includes that the data transmission is received based on a first transmission power for the first set of data tones and a second transmission power for the second set of data tones.

In aspect 23, the method of any of aspects 18-22 further includes that when the receiving device is a base station, the method further includes: indicating to a UE multiple MCS for the first set of data tones and the second set of data tones.

In aspect 24, the method of any of aspects 18-23 further includes that the base station indicates the first MCS for the first set of data tones and the second MCS for the second set of data tones.

In aspect 25, the method of any of aspects 18-24 further includes that when the receiving device is a UE, the method further includes: receiving, from a base station, an indication of multiple MCS for the first set of data tones and the second set of data tones.

In aspect 26, the method of any of aspects 18-25 further includes that the UE receives the indication of the first MCS for the first set of data tones and the second MCS for the second set of data tones.

In aspect 27, the method of any of aspects 18-26 further includes that when the receiving device is a base station, the method further including: indicating to a UE a power constraint.

In aspect 28, the method of any of aspects 18-27 further includes that the power constraint is indicated based on an MCS signaled to the UE.

In aspect 29, the method of any of aspects 18-28 further includes that the power constraint is explicitly signaled to the UE.

In aspect 30, the method of any of aspects 18-29 further includes that the receiving device is a UE, and where the UE applies a fixed power constraint.

In aspect 31, the method of any of aspects 18-30 further includes that when the receiving device is a UE, the method further includes: receiving an indication of a power constraint from a base station.

In aspect 32, the method of any of aspects 18-31 further includes that the power constraint is indicated based on an MCS signaled to the UE.

In aspect 33, the method of any of aspects 18-32 further includes that the power constraint is explicitly signaled to the UE

Aspect 34 is an apparatus for wireless communication including at least one processor coupled to a memory and configured to implement a method as in any of aspects 18 to 33.

Aspect 35 is an apparatus for wireless communication including means for implementing a method as in any of aspects 18 to 33.

Aspect 36 is a computer-readable medium storing computer executable code, where the code when executed by a processor causes the processor to implement a method as in any of aspects 18 to 33.

Aspect 37 is yet another method of wireless communication at a transmitting device. The method (like other techniques discussed herein) may include one or more optional actions and/or steps (such as those that follow). For example, the method may include generating a first PAPR reduction signal from a first set of PRTs within a plurality of tones, where the first set of PRTs overlaps with a first set of data tones. The method may also include generating a second PAPR reduction signal from a second set of PRTs within the plurality of tones, where the second set of PRTs overlaps a second set data tones, where the first set of PRTs does not overlap with the second set of PRTs, and the first set of data tones does not overlap with the second set of data tones. The method may also include applying a first MCS to the first set of data tones and a second MCS to the second set of data tones s. The method may optionally include transmitting a data transmission using a waveform based at least in part on the first PAPR reduction signal and the second PAPR reduction signal.

Aspect 38 is a method of wireless communication at a transmitting device, including: determining a sequence that includes a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence; selecting a location of one or more PRT among a plurality of tones for a data transmission based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones; and sending the data transmission to a receiver, where a PAPR for the data transmission is reduced by the one or more PRT.

In aspect 39, the method of aspect 38 further includes that the set of integers within the sequence forms a closed interval.

In aspect 40, the method of aspect 38 or aspect 39 further includes: applying an offset to each integer within the set of integers and select the location of the one or more PRT among the plurality of tones based on the set of integers with the offset.

In aspect 41, the method of any of aspects 38-40 further includes that the plurality of tones further includes one or more data tone.

In aspect 42, the method of any of aspects 38-41 further includes that each integer within the sequence corresponds to one location for one of the one or more PRT within the plurality of tones.

In aspect 43, the method of any of aspects 38-42 further includes that the data transmission includes one or more resource blocks within an OFDM symbol.

In aspect 44, the method of any of aspects 38-43 further includes that the one or more PRT is selected to be ignored by the receiver and the one or more data tone is transmitted to be decoded by the receiver.

In aspect 45, the method of any of aspects 38-44 further includes that the sequence is based on an optimal Golomb ruler.

In aspect 46, the method of any of aspects 38-45 further includes that the sequence is based on a Ruzsa construction.

In aspect 47, the method of any of aspects 38-46 further includes that determining the sequence includes: determining an order of the sequence based on a square root of a number of allocated tones.

In aspect 48, the method of any of aspects 38-47 further includes that determining the sequence further includes rounding the square root of the number to a closest whole number.

In aspect 49, the method of any of aspects 38-48 further includes that determining the sequence further includes adding a constant to the closest whole number.

In aspect 50, the method of any of aspects 38-49 further includes that the order number corresponds to total number of integers within the sequence.

In aspect 51, the method of any of aspects 38-50 further includes that determining the sequence further includes: determining an optimal Golomb ruler based on the order of the sequence; and determining PRT indices based on the marks on the optimal Golomb ruler.

In aspect 52, the method of any of aspects 38-51 further includes that determining the sequence further includes: determining an optimal Golomb ruler based on the order of the sequence; and determining PRT indices based on the marks on the optimal Golomb ruler after applying an offset to the integers within the order of the sequence.

Aspect 53 is an apparatus for wireless communication including at least one processor coupled to a memory and configured to implement a method as in any of aspects 38 to 52.

Aspect 54 is an apparatus for wireless communication including means for implementing a method as in any of aspects 38 to 52.

Aspect 55 is a computer-readable medium storing computer executable code, where the code when executed by a processor causes the processor to implement a method as in any of aspects 38 to 52.

Aspect 56 is a method of wireless communication at a receiving device, including: determining a sequence that includes a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence; receiving a data transmission from a transmitting device, where the data transmission includes a plurality of tones; identifying a location of one or more PRT among the plurality of tones based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones; and ignore the one or more PRT when decoding the data transmission.

In aspect 57, the method of aspect 56 further includes that decoding the data transmission further includes decoding one or more data tones within the plurality of tones.

In aspect 58, the method of aspect 56 or aspect 57 further includes: transmitting an indication to the transmitting device to send the data transmission with the one or more PRT.

In aspect 59, the method of any of aspects 56-58 further includes that each integer within the sequence corresponds to one location for one of the one or more PRT within the plurality of tones.

In aspect 60, the method of any of aspects 56-59 further includes that the data transmission includes one or more resource blocks within an OFDM symbol.

In aspect 61, the method of any of aspects 56-60 further includes that the sequence is based on an optimal Golomb ruler.

In aspect 62, the method of any of aspects 56-61 further includes that the sequence is based on a Ruzsa construction.

In aspect 63, the method of any of aspects 56-62 further includes that identifying the location of the one or more PRT includes: determining an order of the sequence based on a square root of a number of allocated tones.

In aspect 64, the method of any of aspects 56-63 further includes that identifying the location of the one or more PRT further includes rounding the square root of the number to a closest whole number.

In aspect 65, the method of any of aspects 56-64 further includes that identifying the location of the one or more PRT further includes adding a constant to the closest whole number.

In aspect 66, the method of any of aspects 56-65 further includes that the order number corresponds to total number of integers within the sequence.

In aspect 67, the method of any of aspects 56-66 further includes that identifying the location of the one or more PRT further includes: determining an optimal Golomb ruler based on the order of the sequence; and determining PRT indices based on the marks on the optimal Golomb ruler.

In aspect 68, the method of any of aspects 56-67 further includes that identifying the location of the one or more PRT further includes determining an optimal Golomb ruler based on the order of the sequence; and determining PRT indices based on the marks optimal Golomb ruler after applying an offset to the integers within the order of the sequence.

Aspect 69 is an apparatus for wireless communication including at least one processor coupled to a memory and configured to implement a method as in any of aspects 56 to 68.

Aspect 70 is an apparatus for wireless communication including means for implementing a method as in any of aspects 56 to 68.

Aspect 71 is a computer-readable medium storing computer executable code, where the code when executed by a processor causes the processor to implement a method as in any of aspects 56 to 68.

Aspect 72 is yet another method of wireless communication at a transmitting device. The method (like other techniques discussed herein) may include one or more optional actions and/or steps (such as those that follow). For example, the method may include determining a sequence that includes a set of integers, where each integer within the sequence is distinct and a difference between any pair of integers within the sequence is distinct from other pairs of integers within the sequence. The method may also include selecting a location of one or more PRT among a plurality of tones for a data transmission based on the sequence, where the integers within the sequence correspond to the location of the one or more PRT within the plurality of tones. Further, the method may optionally include sending the data transmission to a receiver, where a PAPR for the data transmission is reduced by the one or more PRT.