Apparatus and methods for phase noise mitigation in wireless systems
11581911 · 2023-02-14
Assignee
Inventors
Cpc classification
H04L25/0256
ELECTRICITY
International classification
H04L12/28
ELECTRICITY
H04L25/03
ELECTRICITY
H04L1/00
ELECTRICITY
Abstract
Apparatus and methods for phase noise mitigation in wireless systems and networks. In one embodiment, the apparatus and methods provide enhanced wireless services which provide enhanced performance to 5G millimeter wave system entities base stations (gNodeBs) and their backhaul in support of low-latency and high-throughput operation of these components and the network as a whole. In one variant, an enhanced phase noise mitigation mechanism is provided which has a robust performance in operating in very high frequencies such as millimeter wave spectrum. In yet other implementations, the methods and apparatus described herein can be utilized with respect to mobile devices such as between 5G NR millimeter-wave capable UEs and corresponding gNBs.
Claims
1. A computerized method for correcting phase error in a received signal, comprising: receiving symbols of an input data block comprising a first data symbol and a last data symbol; applying an equalization process to the symbols starting with the first data symbol to produce an equalized block of input data symbols; de-rotating the equalized block of the input data symbols using a first value; estimating second value for the equalized block of the input data symbols using an LCBQ (low complexity blind-QAM) based algorithm; and applying a phase error compensation to the equalized block of input symbols based at least in part on the estimated second value.
2. The computerized method of claim 1, wherein the estimating the second value comprises estimating the second value based at least on a concatenation of at least a portion of points of a constellation formed by individual ones of the symbols of the input data block which exceed a prescribed limit.
3. The computerized method of claim 2, further comprising selecting the at least portion of points of the constellation based at least in part on a specific Cartesian coordinate area of the constellation.
4. The computerized method of claim 1, further comprising applying the second value as part of estimating a phase error compensation for a subsequent input data block, the input data block and the subsequent input data block each being part of a TDM (time division multiplexed) slot data structure.
5. The computerized method of claim 1, wherein the receiving the symbols of the input data block comprises receiving the input data block over a physical channel, the physical channel comprising a wireless channel having a carrier frequency within a mmWave band.
6. A computerized apparatus for use in a wireless infrastructure, the computerized apparatus comprising: digital processing apparatus; an equalization apparatus in data communication with the digital processing apparatus; at least one wireless interface in data communication with the digital processing apparatus, the at least one wireless interface operative to utilize a mmWave radio frequency (RF) band for communication of data; and a storage device in data communication with the digital processing apparatus, the storage device comprising a storage medium having at least one computer program, the at least one computer program configured to, when executed on the digital processing apparatus, cause the computerized apparatus to: apply a non-iterative phase noise compensation algorithm for at least reception of the data; wherein: the non-iterative phase noise compensation algorithm is applied after equalization by the equalization apparatus; and the non-iterative phase noise compensation algorithm is configured to: (i) perform a de-rotation before the equalization, and estimate a second de-rotation based at least on a subset of constellation points associated with the data, the estimate occurring without further iteration.
7. The computerized apparatus of claim 6, wherein the computerized apparatus further comprises a 3rd Generation Partnership Project (3GPP) Fifth Generation New Radio Unlicensed (5G NR-U) capable gNodeB.
8. The computerized apparatus of claim 6, wherein the computerized apparatus comprises a Fifth Generation New Radio (5G NR) capable UE (user equipment).
9. The computerized apparatus of claim 6, wherein the subset of the constellation points associated with the data is selected based on a plurality of spatial limit criteria.
10. The computerized apparatus of claim 9, wherein the subset comprises only corners of a constellation.
11. The computerized apparatus of claim 6, wherein the subset of constellation points associated with the data is selected based at least in part on a specific Cartesian coordinate area of a constellation.
12. The computerized apparatus of claim 6, wherein the estimation of the second de-rotation is based at least on a concatenation of the subset of the constellation points formed by symbols of an input data block which exceed a prescribed limit.
13. Computer readable apparatus comprising a non-transitory storage medium, the non-transitory storage medium comprising at least one computer program, the at least one computer program comprising a plurality of instructions which are configured to, when executed on a processing device, cause compensation for phase noise within a wireless device by at least: receipt of a slot comprising a plurality of data blocks; equalization of at least a first data block of the plurality of data blocks to produce an uncompensated but equalized constellation for the first data block; application of at least one (i) a rotation or (ii) a spatial limitation to the uncompensated but equalized constellation; execution of a low complexity blind-QAM (LCBQ) algorithm to estimate, based on the at least one (i) the rotation or (ii) the spatial limitation, a residual phase noise error parameter; and utilization of at least the estimated residual phase noise error parameter to apply a compensation to the first data block; wherein the LCBQ algorithm is configured to enable selective tradeoff between at least implementation complexity and performance.
14. The computer readable apparatus of claim 13, wherein the plurality of instructions are further configured to, when executed on the processing device, cause the compensation for the phase noise within the wireless device by at least: a determination of an initial rotation value for one of the plurality of data blocks within a slot subsequent to the first data block via the utilization of the estimated residual phase noise error parameter.
15. The computer readable apparatus of claim 14, wherein: the plurality of data blocks have been modulated according to a symmetric modulation scheme; and the application of the at least one of the (i) rotation or (ii) the at least one spatial limitation to the uncompensated but equalized constellation comprises (i) application of a rotation angle that is configured to utilize a symmetry of the uncompensated but equalized constellation, and (ii) utilization of at least one spatial limitation that eliminates at least a majority of the data of the uncompensated but equalized constellation prior to the estimation of the residual phase noise error parameter.
16. The computer readable apparatus of claim 15, wherein the estimation of the residual phase noise error parameter comprises estimation of a second rotation angle.
17. The computer readable apparatus of claim 13, wherein the selective tradeoff comprises at least a user-selectable degree of trade-off via at least one of a software configuration or firmware configuration.
18. The computer readable apparatus of claim 13, wherein the selective tradeoff is dynamically variable and controlled via one or more machine-based algorithms that are self-optimizing based on one or more operating environment conditions.
19. The computer readable apparatus of claim 18, wherein the one or more operating environment conditions comprise an element of weather.
20. The computer readable apparatus of claim 13, wherein the computer readable apparatus is configured to be executed in a wireless apparatus having an air interface, the wireless apparatus comprising one of (i) a computerized user device, (ii) a small cell, or (iii) a microcell.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
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(23) All figures © Copyright 2019 Charter Communications Operating, LLC. All rights reserved.
DETAILED DESCRIPTION
(24) Reference is now made to the drawings wherein like numerals refer to like parts throughout.
(25) As used herein, the term “application” (or “app”) refers generally and without limitation to a unit of executable software that implements a certain functionality or theme. The themes of applications vary broadly across any number of disciplines and functions (such as on-demand content management, e-commerce transactions, brokerage transactions, home entertainment, calculator etc.), and one application may have more than one theme. The unit of executable software generally runs in a predetermined environment; for example, the unit could include a downloadable Java Xlet™ that runs within the JavaTV™ environment.
(26) As used herein, the terms “client device” or “user device” or “UE” include, but are not limited to, set-top boxes (e.g., DSTBs), gateways, modems, personal computers (PCs), and minicomputers, whether desktop, laptop, or otherwise, and mobile devices such as handheld computers, PDAs, personal media devices (PMDs), tablets, “phablets”, smartphones, and vehicle infotainment systems or portions thereof.
(27) As used herein, the term “computer program” or “software” is meant to include any sequence or human or machine cognizable steps which perform a function. Such program may be rendered in virtually any programming language or environment including, for example, C/C++, Fortran, COBOL, PASCAL, Ruby, Python, assembly language, markup languages (e.g., HTML, SGML, XML, VoXML), and the like, as well as object-oriented environments such as the Common Object Request Broker Architecture (CORBA), Java™ (including J2ME, Java Beans, etc.) and the like.
(28) As used herein, the term “DOCSIS” refers to any of the existing or planned variants of the Data Over Cable Services Interface Specification, including for example DOCSIS versions 3.0, 3.1 and 4.0.
(29) As used herein, the term “headend” or “backend” refers generally to a networked system controlled by an operator (e.g., an MSO) that distributes programming to MSO clientele using client devices, or provides other services such as high-speed data delivery and backhaul.
(30) As used herein, the terms “Internet” and “internet” are used interchangeably to refer to inter-networks including, without limitation, the Internet. Other common examples include but are not limited to: a network of external servers, “cloud” entities (such as memory or storage not local to a device, storage generally accessible at any time via a network connection, and the like), service nodes, access points, controller devices, client devices, etc.
(31) As used herein, the term “LTE” refers to, without limitation and as applicable, any of the variants or Releases of the Long-Term Evolution wireless communication standard, including LTE-U (Long Term Evolution in unlicensed spectrum), LTE-LAA (Long Term Evolution, Licensed Assisted Access), LTE-A (LTE Advanced), 4G LTE, WiMAX, VoLTE (Voice over LTE), and other wireless data standards.
(32) As used herein, the term “memory” includes any type of integrated circuit or other storage device adapted for storing digital data including, without limitation, ROM, PROM, EEPROM, DRAM, SDRAM, (G)DDR/2/3/4/5/6 SDRAM, EDO/FPMS, RLDRAM, SRAM, “flash” memory (e.g., NAND/NOR), 3D memory, stacked memory such as HBM/HBM2, spin-RAM and PSRAM.
(33) As used herein, the terms “microprocessor” and “processor” or “digital processor” are meant generally to include all types of digital processing devices including, without limitation, digital signal processors (DSPs), reduced instruction set computers (RISC), general-purpose (CISC) processors, microprocessors, GPUs (graphics processing units), gate arrays (e.g., FPGAs), PLDs, reconfigurable computer fabrics (RCFs), array processors, secure microprocessors, and application-specific integrated circuits (ASICs). Such digital processors may be contained on a single unitary IC die, or distributed across multiple components.
(34) As used herein, the term “mmWave” refers to, without limitation, any device or technology or methodology utilizing millimeter wave spectrum between 24 GHz and 300 GHz.
(35) As used herein, the terms “MNO” or “mobile network operator” refer to a cellular, satellite phone, WMAN (e.g., 802.16), or other network service provider having infrastructure required to deliver services including without limitation voice and data over those mediums. The term “MNO” as used herein is further intended to include MVNOs, MNVAs, and MVNEs.
(36) As used herein, the terms “MSO” or “multiple systems operator” refer to a cable, satellite, or terrestrial network provider having infrastructure required to deliver services including programming and data over those mediums.
(37) As used herein, the terms “network” and “bearer network” refer generally to any type of telecommunications or data network including, without limitation, hybrid fiber coax (HFC) networks, satellite networks, telco networks, and data networks (including MANs, WANs, LANs, WLANs, internets, and intranets). Such networks or portions thereof may utilize any one or more different topologies (e.g., ring, bus, star, loop, etc.), transmission media (e.g., wired/RF cable, RF wireless, millimeter wave, optical, etc.) and/or communications technologies or networking protocols (e.g., SONET, DOCSIS, IEEE Std. 802.3, ATM, X.25, Frame Relay, 3GPP, 3GPP2, LTE/LTE-A/LTE-U/LTE-LAA, 5GNR, WAP, SIP, UDP, FTP, RTP/RTCP, H.323, etc.).
(38) As used herein the terms “5G” and “New Radio (NR)” refer without limitation to apparatus, methods or systems compliant with 3GPP Release 15, and any modifications, subsequent Releases, or amendments or supplements thereto which are directed to New Radio technology, whether licensed or unlicensed, as well as any related technologies such as 5G NR-U.
(39) As used herein, the term “QAM” refers to modulation schemes used for sending signals over e.g., cable or other networks. Such modulation scheme might use any constellation level (e.g. QPSK, 16-QAM, 64-QAM, 256-QAM, etc.) depending on details of a network. A QAM may also refer to a physical channel modulated according to the schemes.
(40) As used herein, the term “quasi-licensed” refers without limitation to spectrum which is at least temporarily granted, shared, or allocated for use on a dynamic or variable basis, whether such spectrum is unlicensed, shared, licensed, or otherwise.
(41) As used herein, the term “server” refers to any computerized component, system or entity regardless of form which is adapted to provide data, files, applications, content, or other services to one or more other devices or entities on a computer network.
(42) As used herein, the term “storage” refers to without limitation computer hard drives, DVR device, memory, RAID devices or arrays, optical media (e.g., CD-ROMs, Laserdiscs, Blu-Ray, etc.), or any other devices or media capable of storing content or other information.
(43) As used herein the terms “unlicensed” and “unlicensed spectrum” refer without limitation to radio frequency spectrum (e.g., from the sub-GHz range through 100 GHz) which is generally accessible, at least on a part time basis, for use by users not having an explicit license to use, such as e.g., ISM-band, 2.4 GHz bands, 5 GHz bands, 6 GHz bands, quasi-licensed spectrum such as CBRS, 60 GHz (V-Band), 5G NR-U bands, and others germane to the geographic region of operation (whether in the U.S. or beyond) that will be appreciated by those of ordinary skill given the present disclosure.
(44) As used herein, the term “Wi-Fi” refers to, without limitation and as applicable, any of the variants of IEEE Std. 802.11 or related standards including 802.11 a/b/g/n/s/v/ac/ad/ax, 802.11-2012/2013 or 802.11-2016, as well as Wi-Fi Direct (including inter alia, the “Wi-Fi Peer-to-Peer (P2P) Specification”, incorporated herein by reference in its entirety).
(45) As used herein, the term “xNB” refers to any 3GPP-compliant node including without limitation eNBs (eUTRAN) and gNBs (5G NR).
OVERVIEW
(46) In one exemplary aspect, the present disclosure provides improved architectures, methods and apparatus for providing enhanced wireless services which, inter alia, utilize improved phase noise mitigation mechanism for mmWave spectrum. In one exemplary embodiment, an LCBQ (low complexity blind QAM) based approach is utilized to simultaneously optimize both performance and low processing and hardware overhead. As such, the exemplary embodiments herein enable, among other things, an enhancement for tracking phase noise which can have low implementation complexity and can be advantageously used in a broad range of mmWave devices including access nodes (e.g. 5G NR gNBs), backhaul devices, and user devices (e.g. 5G NR UEs or IoT devices).
(47) In one aspect, a 5G mmWave-based transceiver is described, wherein the receiver includes an Enhanced Phase Noise Estimator (ENPE) module which implements the aforementioned LCBQ algorithms. The ENPE is an apparatus for correcting phase error in a received data block which in one implementation includes a first phase de-rotator, hard limiter, phase estimator, and a second phase de-rotator. In one configuration, the phase rotator includes a low complexity mechanism that blindly track the phase error in the received data block, while the phase de-rotators are configured to apply the phase compensation to the received data block in a single operation (without iteration).
(48) In other variants, the LCBQ algorithms and logic are configured to be dynamically variable (e.g., as to one or more parameters associated with the compensation processes such as number of iterations) whether by a user/operator, designer, or a computerized process or controller such as one implementing machine learning (ML) or AI (artificial intelligence) algorithms, thereby enabling the EPNE-equipped device to automatically and dynamically adapt to an operating condition or environment.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
(49) Exemplary embodiments of the apparatus and methods of the present disclosure are now described in detail. While these exemplary embodiments are described in the context of a managed network of a service provider (e.g., MSO and/or MNO networks), other types of radio access technologies (“RATs”), other types of networks and architectures that are configured to deliver digital data (e.g., files, text, images, games, software applications, video and/or audio) may be used consistent with the present disclosure. Such other networks or architectures may be broadband, narrowband, or otherwise, the following therefore being merely exemplary in nature.
(50) It will also be appreciated that while described generally in the context of a network providing service to a customer or consumer or end user or subscriber (i.e., within a prescribed service area, venue, or other type of premises, or one mobile in nature), the present disclosure may be readily adapted to other types of environments including, e.g., outdoors, commercial/retail, or enterprise domain (e.g., businesses), or even governmental uses. Yet other applications are possible.
(51) Moreover, while described in the context of quasi-licensed or unlicensed spectrum, it will be appreciated by those of ordinary skill given the present disclosure that various of the methods and apparatus described herein may be applied to reallocation/reassignment of spectrum or bandwidth within a licensed spectrum context; e.g., for cellular voice or data bandwidth/spectrum allocation, such as in cases where a given service provider must alter its current allocation of available spectrum to users.
(52) Further, while some aspects of the present disclosure are described in detail with respect to so-called 5G “New Radio” (3GPP Release 15 and TS 38.XXX Series Standards and beyond), such aspects are generally access technology “agnostic” and hence may be used across different access technologies, and can be applied to, inter alia, any type of P2MP (point-to-multipoint) or MP2P (multipoint-to-point) technology.
(53) Additionally, while described in the context of a given exemplary modulation approach (e.g., 64-QAM), it will be appreciated that the methods and apparatus of the present disclosure may be readily adapted to other modulation schemes such as e.g., QPSK and BPSK by those of ordinary skill, when given the present disclosure.
(54) Other features and advantages of the present disclosure will immediately be recognized by persons of ordinary skill in the art with reference to the attached drawings and detailed description of exemplary embodiments as given below.
(55) Phase Noise—
(56) Before discussing the exemplary embodiments of the methods and apparatus of the present disclosure, it is useful to review in detail exemplary use cases for these improved methods and apparatus, specifically in terms of mmWave applications, to provide context.
(57)
(58)
(59)
(60) Methodology
(61) With the foregoing as a backdrop, exemplary embodiments of improved LCBQ-based methods of phase noise tracking and compensation in scenarios such as those of
(62)
(63) Per step 201 of
(64) Per step 203, the first block of input data B (such as the first (D) of
(65) Per step 205, the received block of data is equalized. The equalization corrects the phase and amplitude of the received data resulting from phase and amplitude variation in the physical wireless channel.
(66) Per step 207, the block of data is de-rotated by θ, where:
Y=Eq(B)*e.sup.−j*θ (3)
(67) where Eq (B) is the equalized data block.
(68) Next, per step 209, the value of a (which can be thought of as a residual rotation or phase noise left uncorrected from the initial rotation) is estimated, and the block of data is de-rotated by α per step 211. It should be noted that step 209 is one area of significant departure from the prior art PLE and BQ approaches; i.e., a low-complexity approach for estimation of α (described subsequently herein in greater detail) is used in the embodiment of
(69) Per step 215, if the last block of the current time slot has been processed, the method proceeds to a wait state 213 awaiting receipt of more blocks (e.g., associated with the next slot) for processing. If the last block of the current slot has not been processed per step 215, then the next block is queued (e.g., its index incremented by 1) and θ is assigned a value of θ=θ+α, per step 217. That is to say that the last value of θ used (e.g., 0 for block B=1 and other values thereafter for blocks B=2 and beyond) is adjusted by the then-current value of α. This value (α) is utilized so as to provide a “best estimate” of the phase noise at the end of the last block (e.g., B=1 in the above example) just processed, which should in theory be similar to that at the first symbol of the new block (B=B+1) being processed, since the physical channel does change appreciably between the end of the first block and the new block.
(70)
(71) Per step 227, the block (constellation) is concatenated within the ROIs (e.g., to isolate the corners).
(72) Per step 229, the value of the residual error a is then estimated. The constellation is then de-rotated by α (step 231).
(73)
(74)
(75) As a brief aside, one ostensibly “ideal” location for a corner (e.g., the NE corner) of the 64-QAM constellation is located at (7+7j)/sqrt(42) (see
(76)
(77) Table 1 below lists exemplary corner constellation points and distances of adjacent points as a function of exemplary modulation types.
(78) TABLE-US-00002 TABLE 1 Modulation Corner Distance to Level Constellation Point Adjacent Point QPSK (1 + 1j)/sqrt(2) 2/sqrt(2) 16-QAM (3 + 3j )/sqrt(10) 2/sqrt(10) 64-QAM (7 + 7j)/sqrt(42) 2/sqrt(42) 256-QAM (15 + 15j)/sqrt(170) 2/sqrt(170)
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(80) Per step 221 of the method 220, a first block of input data (B=1) is received, and the value of θ is assigned a value of θ=0 for initialization. The value of the symbol index S is set to S=1.
(81) Next, per step 223, the first symbol S (S=1) of the received block of input data is obtained and equalized by the equalizer on a symbol-by-symbol basis per steps 224 through 227, until all symbols within a given block B are equalized.
(82) Next, per step 229 the de-rotated data is used to estimate the phase noise estimate α. As above, the low complexity (LC) methodology is applied in step 229 to determine the estimate of α.
(83) At step 230, the block is de-rotated by the estimated phase α from step 229.
(84) Next, per step 231, the method 220 checks if the last block of the current slot has been compensated. If not, the method proceeds to process the next block per step 233, and the latest value of α is used in determining the new value of θ (i.e., θ=θ+α).
(85) It will also be appreciated that while certain embodiments described herein assume or implement phase noise tracking and correction on a block-by-block (B) basis, it is also possible to track and/or correct the phase noise based on other criteria; e.g., on a sub-block basis. For example, in one such approach, some fraction or increment of a given data block (B) could act as the basis for phase noise tracking/correction, such as where the phase noise algorithm is performed on one-half of a block such that a lesser number of samples/symbols are utilized to estimate the phase error. Such reduced-data approach may also be performed more frequently, such as at twice the “full block” frequency in the foregoing example of ½ block processing. As such, since less data is used to form the estimation (and subsequent correction), it will typically be less accurate than if a full block of data (i.e., all symbols therein) were utilized as previously described. However, such reduced-accuracy estimates can be generated more frequently if desired. This approach may be useful in, for instance, contexts where the phase noise is very large such that the phase error within a block is significant enough to cause higher bit error rate (BER). The BER data may also be used as a feedback for adjustment of the process (e.g., what fraction of each block is sampled/estimated, and/or how often such estimation is performed), similar to the approach of
(86) It will also be appreciated that in cases of low phase noise (or low phase noise variation with time), subsets of either (i) the blocks (B) within a given slot, or (ii) the symbols (S) within a given block (B), may be used as the basis for phase noise correction. For instance, in one such approach, the algorithm is modified such that only every other block (B=1, B+2, B+4, . . . ) of data in the slot is selected for processing. As another example, only the first or last X number of the total number N of data blocks, or the middle X blocks of N, may be selected for processing. Similarly, only subsets of the symbols within a given block may be selected (whether or not all blocks of the current slot are processed or not).
(87)
(88) Next, the received data block is equalized per step 253, and then de-rotated by a first value (θ.sub.1) per step 255 to produce a first constellation. This first constellation is limited according to one or more criteria per step 257. In parallel, the same data (first constellation) is de-rotated by a different value θ.sub.2 (e.g., 90 degrees) per step 258 and subsequently limited by one or more criteria per step 259. The two results are then added per step 260 to form a composite, spatially limited (e.g., corners only) constellation of symbol data which is then used as a basis for the residual error per step 262, which is ultimately applied per step 264 to the entire data block.
(89)
(90) Per step 279, if the last block is not encountered, the process proceeds to step 281 wherein the block count (B) is incremented.
(91) Upon encountering the last block at step 279, error data for the slot (or portions thereof, or even multiple slots) is obtained by the receiver per step 283.
(92) Per step 285, the error data is evaluated (e.g., against a criterion) and if adjustment is needed to the index (N) (e.g., to add or reduce the number of iterations of the residual phase error (α) determination), then such adjustment is made per step 289, and the next queued slot received and processed with the adjusted index. Alternatively, if no adjustment is needed, then the method proceeds to step 271 and the next slot is processed without adjustment.
(93) It will be appreciated that the methodology of
(94)
(95) Moreover, under higher SNR conditions (such as e.g., above 15 dB), the effect of phase noise may not be as significant as those under low SNR conditions); hence, the LCBQ algorithm in effect provides its optimization within what for many applications will be the “most important” range of SNR conditions (i.e., low and very low SNR conditions).
(96)
(97) Phase Noise Compensation Apparatus—
(98) Referring now to
(99)
y(n)=a(n)e.sup.jα(n) (5)
(100) where: α(n) is the modulated data n is symbol number α(n) is phase noise at sample time n
(101) The phase noise α (n) can be modeled as a random time-varying phase.
(102) The data symbols α(n) may be modulated according to one of the digital modulation schemes such as m-ary PSK (e.g. QPSK) or m-ary QAM (e.g. 16 QAM or 64 QAM). The modulation scheme may also vary from one symbol to another, or across different blocks. It will be appreciated, however, that the exemplary embodiments described herein are applicable only to modulation schemes that have a prescribed symmetry (e.g., square or rectangular), such as those listed above. However, the techniques and apparatus described herein may be readily adapted by those of ordinary skill given the present disclosure to other types of modulation schemes such as 32-ary QAM, based on their particular geometric or spatial considerations (whether symmetric or not), consistent with aims of reduced complexity and good performance as in the exemplary “symmetric” contexts described herein.
(103)
(104) The synchronizer 515 estimates and corrects the time and frequency offsets. The frequency offset is caused by the difference between transmitter and receiver's local oscillator frequencies. The time offset is caused by the difference between the sampling phase of transmitter clock and receiver clock. The synchronization block 515 corrects the frequency and phase of the incoming data block so that the channel estimator 506 and equalizer 507 processes the compensated block of data. The synchronizer 515 may also include mechanisms for frame and time slot detection.
(105) The channel estimator block 506 obtains an estimate of the channel response based on the reference symbols which are known to the receiver. Channel estimation is a critical task in wireless system. The channel estimation performance affects the performance of several blocks in a wireless receiver. The channel response is used by the equalizer 507 for the equalization. One scheme is to use Least-Square (LS) or Minimum-Mean-Square (MMSE) algorithms to implement the channel estimator.
(106) The equalizer module 507 equalizes the received signal y(n). The wireless channel changes the amplitude and phase of the transmitted signal. The role of the equalizer 507 is to compensate the phase and amplitude of the received signal due to e.g., channel impairments. One implementation for equalizer 507 is a linear equalizer, although other approaches may be used.
(107) The Enhanced Phase Noise Estimator (EPNE) 509 includes the LCBQ logic previously described, and in one embodiment is a blind phase noise estimator. The EPNE estimates the phase noise as previously discussed and applies the estimated phase noise to the received data block(s). Hence, the output data from EPNE has been compensated for the phase noise variation.
(108) The decoder module 511 receives the data from the output of EPNE and decodes the transmitted bits. The module 511 may include a detector module such as Maximum-Likelihood, Sphere Decoder, Linear detector, and Forward Error Correction (FEC) Decoder, systematic (e.g., turbo) decoder, LDPC decoder or Maximum a Posteriori Decoder (MAP).
(109) The output buffer 513 stores the received decoder output and stream the data to the end user bit-by-bit.
(110) The components of the device 503 may be individually or partially implemented in software, firmware or hardware. For example, one or more elements of receiver 505 may be implemented in whole or in part as one or more set of instructions running on one or more programmable logic arrays such as microprocessor, digital signal processor, embedded processor, GPU, Field Programmable Gate Arrays (FPGA), ASICs (Application-Specific Integrated Circuits) or fixed arrays (e.g. transistors and gates).
(111)
(112) The first phase de-rotator 517 rotates the received data from the output of the equalizer r(n) for each block (or symbol in the block, depending on configuration) by an initial phase θ.sub.0, where:
x(n)=r(n)*e.sup.jκ.sup.
(113) The hard limiter 519 limits the outer constellation points above certain limits and creates a vector Z according to the following equation:
(114)
(115) The phase estimator 521 estimates the phase noise for each block as
(116)
(117) where: {circumflex over (α)} is the estimated phase noise for data block B Z.sub.R is the real part of vector Z Z.sub.I is the real part of vector Z Z.sub.T is the transpose matrix operation of Z
(118) As previously discussed, in one embodiment, the phase noise is assumed to be constant for the duration of any given block of data. The phase de-rotator 523 corrects the phase of data block using Eqn. (9)
Y=Y*e.sup.−j{circumflex over (α)} (9)
(119) The hard limiter 519 limits the outer constellation points e.g., above certain limits, and creates a vector of Z according to the above equation.
(120)
(121) Exemplary mmWave System—
(122) Referring now to
(123) As shown in
(124) Similarly, the data center/aggregator backhaul device 604 may be backhauled to an MSO core and/or 5GC 609 as shown via wireless, wireline or optical links 607 as shown.
(125) The gNBs 602 of
(126) Accordingly, it will be appreciated that the phase noise compensation techniques described herein may be utilized in literally any (or all) portions of the foregoing architecture where mmWave-band RF air interfaces or backhauls are utilized, such as between UE/IoT and micro-cell, between micro-cell and macro-cell, between macro-cell and backhaul aggregator, and between the aggregator and the core, depending on network topology and performance requirements.
(127) Backhaul/Aggregator Apparatus—
(128)
(129) In one exemplary embodiment as shown, the CBSD/gNB includes, inter alia, a processor apparatus or subsystem 705, a program memory module 704, EPNE logic 706 (here implemented as software or firmware operative to execute on the processor 705), a local database 702, and mmWave wireless interfaces 703 for communications with the relevant gNBs, and/or other entities (e.g., on the backhaul to the core).
(130) The 5G RF interface 703 may be configured to comply with the relevant PHY according to the relevant 3GPP NR standards which it supports (e.g., NR mmWave). The RF interface 703 may include an RF front end 715 (e.g., ADC/DAC, mixer, etc.), and the antenna(s) 719 of the radios of the aggregator may include parabolic/dish-type antenna elements, or multiple spatially diverse individual elements in e.g., a MIMO- or MISO-type configuration, such that spatial diversity of the received signals can be utilized. Moreover, a phased array or similar arrangement can be used for spatial resolution within the environment, such as based on time delays associated with signals received by respective elements.
(131) In one embodiment, the processor apparatus 705 may include one or more of a digital signal processor, microprocessor, field-programmable gate array, GPU, or plurality of processing components mounted on one or more substrates. The processor apparatus 705 may also comprise an internal cache memory, and a modem. In addition, the processor 705 includes an EPNE of the type previously described herein with respect to
(132) The processing subsystem 705 is in communication with a program memory module or subsystem 704, where the latter may include memory which may comprise, e.g., SRAM, flash and/or SDRAM (e.g., GDDR5 or GDDR6) components. The memory module 704 may implement one or more of direct memory access (DMA) type hardware, so as to facilitate data accesses as is well known in the art. The memory module of the exemplary embodiment contains one or more computer-executable instructions that are executable by the processor apparatus 705. A mass storage device (e.g., HDD or SSD, or NAND/NOR flash or the like) is also provided as shown.
(133) The processor apparatus 705 is configured to execute at least one computer program stored in memory 704 (e.g., the logic of the EPNE module according to the methods of
(134) Wireless Access Node Apparatus—
(135)
(136) In one exemplary embodiment as shown, the gNB includes, inter alia, a processor apparatus or subsystem 805, a program memory module 804, EPNE logic 806 in support of both front-haul links to the small-cells/micro-cells, and backhauls to the network aggregator 604 is used (here implemented as software or firmware operative to execute on the processor 805), a local database 802, and front end wireless interface(s) 803 for communications with the relevant small/micro-cells. A backhaul interface 809 is also shown, which may also utilize mmWave including the EPNE logic previously described.
(137) The 5G RF front-end interface 803 may be configured to comply with the relevant PHY according to the relevant 3GPP NR standards which it supports. The RF front end 815 may be configured to support mmWave frequencies (e.g., via a superheterodyne or other approach), and the antenna(s) 817 of the radios of the gNB(s) may include multiple spatially diverse individual elements in e.g., parabolic dish, or a MIMO- or MISO-type configuration, such that spatial diversity of the received signals can be utilized. As above, a phased array or similar arrangement can be used for spatial resolution within the environment, such as based on time delays associated with signals received by respective elements. Beamforming and “massive MIMO” may also be utilized within the logic of the gNB in support of e.g., the front-end interfaces 803.
(138) In one embodiment, the processor apparatus 805 may include one or more of a digital signal processor, microprocessor, field-programmable gate array, GPU, or plurality of processing components mounted on one or more substrates. The processor apparatus 805 may also comprise an internal cache memory, and a modem. In addition, the processor 805 includes an EPNE of the type previously described. The processing subsystem 805 is in communication with a program memory module or subsystem 804, where the latter may include memory which may comprise, e.g., SRAM, flash and/or SDRAM (e.g., GDDR5 or GDDR6) components. The memory module 804 may implement one or more of direct memory access (DMA) type hardware, so as to facilitate data accesses as is well known in the art. The memory module of the exemplary embodiment contains one or more computer-executable instructions that are executable by the processor apparatus 805. A mass storage device (e.g., HDD or SSD, or NAND/NOR flash or the like) is also provided as shown.
(139) The processor apparatus 805 is configured to execute at least one computer program stored in memory 804 (e.g., the logic of the EPNE module according to the methods of
(140) In some embodiments, the logic 806 also utilizes memory 804 or other storage 802 configured to temporarily and/or locally hold a number of data relating to the various associations for the various small-cells or micro-cells (or even mmWave-enabled UE) which it services under the NR standard(s). In other embodiments, application program interfaces (APIs) may also reside in the internal cache or other memory 804, to enable communication between with other network entities (e.g., via API “calls” to or from the NG core 609 or the aggregator 604).
(141) User Device—
(142)
(143) In one exemplary embodiment as shown, the UE 610 or IoT device 612 includes, inter alia, a processor apparatus or subsystem 905, a program memory module 906, EPNE logic 906 (here also implemented as software or firmware operative to execute on the processor 905), and wireless interfaces 903, 909 for communications with the relevant RANs (e.g., 5G-NR RAN, IEEE Std. 802.11ad, IEEE Std. 802.15.4) and local PAN/WLAN devices, respectively. The RF interfaces 903, 909 are each configured to comply with the relevant PHY standards which it supports, and include an RF front end 915 and antenna(s) elements 917 of the UE or IoT device radios may include multiple spatially diverse individual elements in e.g., a MIMO- or MISO-type configuration, such that spatial diversity of the received signals can be utilized. For example, an exemplary Qualcomm QTM052 mmWave antenna module may be used within the UE/IoT device for mmWave reception and transmission. Beamforming and “massive MIMO” may also be utilized within the logic of the UE/IoT device in support of e.g., the front-end and backend interfaces 903, 909.
(144) In one embodiment, the processor apparatus 805 may include one or more of a digital signal processor, microprocessor, field-programmable gate array, GPU, or plurality of processing components mounted on one or more substrates. For instance, an exemplary Qualcomm Snapdragon x50 5G modem may be used consistent with the disclosure.
(145) The processor apparatus 905 may also comprise an internal cache memory, and a modem. As indicated, the UE includes an ENPE module 509 on the program memory which is in communication with the processing subsystem, where the former may include memory which may comprise, e.g., SRAM, flash and/or SDRAM components. The memory module 904 may implement one or more of direct memory access (DMA) type hardware, so as to facilitate data accesses as is well known in the art. The memory module of the exemplary embodiment contains one or more computer-executable instructions that are executable by the processor apparatus 905. A mass storage device (e.g., HDD or SSD, or NAND/NOR flash or the like, such as via eMCC) is also provided as shown.
(146) Other embodiments may implement the EPNE functionality within dedicated hardware, logic, and/or specialized co-processors (not shown).
(147) As noted, the UE/IoT device 610, 612 may include an EPNE module 509 which is configured to determine estimate and correct the phase noise. In one embodiment, the EPNE module is integrated with the baseband processor 907 (via its execution on the processor). The baseband processor processes the baseband control and data signals for transmission and reception in the RF frond end module 903 and/or the backend interfaces 909.
(148) In some embodiments, the UE also utilizes memory 904 or other storage 902 configured to temporarily hold a number of data relating to the various network associations (e.g., to micro-cells, gNBs, etc.), and for the various services/applications such as voice, etc.) for the various functions described herein.
(149) It will be recognized that while certain aspects of the disclosure are described in terms of a specific sequence of steps of a method, these descriptions are only illustrative of the broader methods of the disclosure, and may be modified as required by the particular application. Certain steps may be rendered unnecessary or optional under certain circumstances. Additionally, certain steps or functionality may be added to the disclosed embodiments, or the order of performance of two or more steps permuted. All such variations are considered to be encompassed within the disclosure disclosed and claimed herein.
(150) While the above detailed description has shown, described, and pointed out novel features of the disclosure as applied to various embodiments, it will be understood that various omissions, substitutions, and changes in the form and details of the device or process illustrated may be made by those skilled in the art without departing from the disclosure. This description is in no way meant to be limiting, but rather should be taken as illustrative of the general principles of the disclosure. The scope of the disclosure should be determined with reference to the claims.
(151) It will be further appreciated that while certain steps and aspects of the various methods and apparatus described herein may be performed by a human being, the disclosed aspects and individual methods and apparatus are generally computerized/computer-implemented. Computerized apparatus and methods are necessary to fully implement these aspects for any number of reasons including, without limitation, commercial viability, practicality, and even feasibility (i.e., certain steps/processes simply cannot be performed by a human being in any viable fashion).