SYSTEM AND METHOD FOR COMMON PHASE ERROR AND INTERCARRIER INTERFERENCE ESTIMATION AND COMPENSATION

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119. 19. (canceled)
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Abstract
A system and method for transmitting an orthogonal frequencydivision multiplexed signal with a group distributed phase tracking reference signal subcarrier structure, and for estimating, and compensating for, both common phase error, and intercarrier interference.
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39 Claims
 119. 19. (canceled)
 20. A method, comprising:
estimating one or more intercarrier interference terms, including; canceling, from a received signal, an estimated common phase error to form a first compensated received signal; and estimating, based on the first compensated received signal, a first intercarrier interference term.  View Dependent Claims (21, 22, 23, 24, 25, 26)
 27. A method, comprising:
estimating one or more intercarrier interference terms, including; canceling, from a received signal, an estimated common phase error to form a first compensated received signal; and jointly estimating, based on the first compensated received signal, L intercarrier interference terms, L being a set integer greater than 0.  View Dependent Claims (28, 29, 30, 31, 32)
 33. A system, comprising:
a receiver, the receiver comprising a processing circuit configured to estimate one or more intercarrier interference terms, including; canceling, from a received signal, an estimated common phase error to form a first compensated received signal; and estimating, based on the first compensated received signal, a first intercarrier interference term.  View Dependent Claims (34, 35, 36, 37, 38, 39)
1 Specification
The present application is a continuation application of U.S. patent application Ser. No. 15/880,419, filed Jan. 25, 2018, which claims priority to and the benefit of U.S. Provisional Application No. 62/541,035 filed Aug. 3, 2017, entitled “SYSTEM AND METHOD FOR PHASE TRACKING REFERENCE SIGNAL (PTRS) STRUCTURE AND FREQUENCY DOMAIN PHASE NOISE COMMON PHASE ERROR (CPE) AND INTERCARRIER INTERFERENCE (ICI) COMPENSATION”. The entire contents of both of the applications identified in this paragraph are incorporated herein by reference.
One or more aspects of embodiments according to the present disclosure relate to communication systems, and more particularly, to a system and method for common phase error and intercarrier interference estimation and compensation.
Phase noise, caused by oscillator imperfections, affects the orthogonality of subcarriers in an orthogonal frequencydivision multiplexing (OFDM) system. The phase noise process may be random in nature and for a phaselocked loop (PLL) based oscillator, it effectively causes a rotation of time domain baseband samples of the inphase and quadrature components (IQ samples) by a small amount, and the randomness can be characterized by a power spectral density (PSD) in the frequency domain. This leads to a common phase error (CPE), which has similar impact on each subcarrier, and intercarrier interference (ICI), which may be different for each subcarrier and may cause scattering of the received constellation points in OFDM based systems. The total power of CPE and ICI observed at the center tone may be the integrated phase noise PN (IPN), which may also be obtained by integrating the PSD of the PN process over the occupied bandwidth (BW). If the phase noise PSD is wide compared to the subcarrier spacing, more of the total power of the phase noise (IPN) will be contributed as ICI instead of as CPE. The phase noise may be particularly severe for higher carrier frequencies such as millimeterwave frequency bands above 6 GHz.
A phase tracking reference signal (PTRS) has been introduced in the New Radio (NR) standard, to enable compensation of oscillator phase noise. PTRS may be utilized at high carrier frequencies (such as millimeterwave) to mitigate phase noise. However, a fully distributed PTRS structure may be suitable only for CPE estimation and compensation, and may not be of use in mitigating ICI.
Aspects of embodiments of the present disclosure are directed toward a system and method for transmitting an orthogonal frequencydivision multiplexed signal with a group distributed phase tracking reference signal subcarrier structure, and for estimating, and compensating for, both common phase error, and intercarrier interference.
According to an embodiment of the present disclosure there is provided a method, including: estimating a channel using demodulation reference signal subcarriers from a received signal; estimating a common phase error term using the estimated channel and phase tracking reference signal subcarriers; and estimating one or more intercarrier interference terms, including: canceling, from the received signal, the estimated common phase error term to form a first compensated received signal; and estimating, based on the first compensated received signal, a first intercarrier interference term.
In one embodiment, the method further includes calculating a value of the transmitted signal in a subcarrier using known PTRS pilots.
In one embodiment, the estimating of the intercarrier interference terms further includes: iteratively, for a range of values of an integer i greater than 1 and less than a set integer L: canceling, from a received signal, the estimated common phase error, and the first through (i−1)th intercarrier interference terms, to form an ith compensated received signal; and estimating, using the ith compensated received signal, an ith intercarrier interference term.
In one embodiment, the estimating of the common phase error includes calculating a phase of the estimated common phase error according to Ĵ[0]=((Ĥ[κ]X[κ])^{H}Y[κ]), wherein: κ is a set of phase tracking reference signal subcarriers; Ĥ[κ] is a diagonal matrix the pth diagonal element of which is equal to the estimated channel response for the pth subcarrier from among the set κ; X[κ] is the transmitted signal in subcarriers from among the set κ; Y[κ] is the received signal in subcarriers from among the set κ; and H as a superscript denotes a conjugate transpose.
In one embodiment, the estimating of the common phase error further includes setting an amplitude of the estimated common phase error to be equal to 1.
In one embodiment, the phase tracking reference signal subcarriers include N_{c}N_{PTRS }subcarriers, arranged in N_{c }groups, each of the N_{c }groups including N_{PTRS }adjacent subcarriers.
In one embodiment, the canceling, from the received signal, the estimated common phase error, and the first through (i−1)th intercarrier interference terms, to form the ith compensated received signal, includes calculating the ith compensated received signal Y_{SIC}[κ_{ii}] according to
Y_{SIC}[κ_{ii}]=Y[κ_{ii}]−Ĵ[0]Ĥ[κ_{ii}]X[κ_{ii}],
for i=1, and
Y_{SIC}[κ_{ii}]=Y[κ_{ii}]−Ĵ[0]Ĥ[κ_{ii}]X[κ_{ii}]−Ĵ[1]Ĥ[κ_{(i−1)(i+1)}]X[κ_{(i−1)(i+1)}]−
Ĵ[−1]Ĥ[κ_{(i+1)(i−1)}]X[κ_{(i+1)(i−1)}]− . . . −Ĵ[i−1]Ĥ[κ_{1(2i−1)}]X[κ_{1(2i−1)}]−
Ĵ[−(i−1)]Ĥ[κ_{(2i−1)1}]X[κ_{(2i−1)1], }
for i>1 wherein:
κ_{ij}={k_{1(i+1)}, . . . , k_{1(N}_{PTRS−j)}, . . . , k_{N}_{c}_{(i+1)}, . . . , k_{N}_{c}_{(N}_{PTRS}_{−j)}}, wherein k_{pq }is the qth subcarrier of the pth group of subcarriers of the phase tracking reference signal subcarriers; Ĥ[κ_{ij}] is a diagonal matrix the pth diagonal element of which is equal to the estimated channel response for the pth subcarrier from among the set κ_{ij}; X[κ_{pq}] is the transmitted signal in subcarriers from among the set κ_{pq}; Y[κ_{ii}] is the received signal in subcarriers from among the set κ_{ii}; Ĵ[0] is the estimated common phase error; and Ĵ[p], for p not equal to zero, is the estimated pth intercarrier interference term.
In one embodiment, the estimating, based on the ith compensated received signal, of the ith intercarrier interference term includes calculating the ith estimated intercarrier interference term Ĵ[i] according to
wherein:
In one embodiment, the method further includes calculating a final compensated received signal Y_{ICI comp}[l] based on a matched filter, wherein an order of the filter is dependent on a number of estimated intercarrier interference terms.
According to an embodiment of the present disclosure there is provided a method, including: estimating a channel using demodulation reference signal subcarriers from a received signal; estimating a common phase error term using the estimated channel and phase tracking reference signal subcarriers; and estimating one or more intercarrier interference terms, including: canceling, from the received signal, the estimated common phase error term to form a first compensated received signal; and jointly estimating, based on the first compensated received signal, L intercarrier interference terms, L being a set integer greater than 0.
In one embodiment, the method further includes calculating a value of the transmitted signal in a subcarrier using known PTRS pilots.
In one embodiment, the estimating of the common phase error includes calculating a phase of the estimated common phase error according to Ĵ[0]=((H[κ]X[κ])^{H}Y[κ]), wherein: κ is a set of phase tracking reference signal subcarriers; Ĥ[κ] is a diagonal matrix the pth diagonal element of which is equal to the estimated channel response for the pth subcarrier from among the set κ; X[κ] is the transmitted signal in subcarriers from among the set κ; Y[κ] is the received signal in subcarriers from among the set κ; and H as a superscript denotes a conjugate transpose.
In one embodiment, the estimating of the common phase error further includes setting an amplitude of the common phase error to be equal to 1.
In one embodiment, the phase tracking reference signal subcarriers include N_{c}N_{PTRS }subcarriers, arranged in N_{c }groups, each of the N_{c }groups including N_{PTRS }adjacent subcarriers.
In one embodiment, the canceling, from the received signal, the estimated common phase error to form a first compensated received signal includes calculating the first compensated received signal Y_{CPEcomp}[κ_{LL}] according to Y_{CPEcomp}[κ_{LL}]=Y[κ_{LL}]−Ĵ[0]Ĥ[κ_{LL}]X[κ_{LL}], wherein: κ_{ij}={k_{1(i+1)}, . . . , k_{1(N}_{PTRS}_{−j)}, . . . , k_{N}_{c}_{(i+1)}, . . . , k_{N}_{c}_{(N}_{PTRS}_{−j)}}, wherein k_{pq }is the qth subcarrier of the pth group of subcarriers of the phase tracking reference signal subcarriers; Ĥ[κ_{LL}] is a diagonal matrix the pth diagonal element of which is equal to the estimated channel response for the pth sub carrier from among the set κ_{LL}; X[κ_{LL}] is the transmitted signal in subcarriers from among the set κ_{LL}; Y[κ_{LL}] is the received signal in subcarriers from among the set κ_{LL}; and Ĵ[0] is the estimated common phase error.
In one embodiment, the jointly estimating, based on the first compensated received signal, of L intercarrier interference terms, includes calculating the L estimated intercarrier interference terms Ĵ according to
wherein:
and
the respective ith columns A_{i}, B_{i}, C_{i}, and D_{i }of A, B, C, and D are:
A_{i}=Re{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}−Re{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]};
B_{i}=−Im{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}−Im{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]};
C_{i}=Im{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}−Im{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]}; and
D_{i}=Re{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}+Re{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]}.
In one embodiment, the method further includes calculating a final compensated received signal Y_{ICI comp}[l] according to Y_{ICI comp}[l]=Ĵ*[0]Y[l]+Ĵ*[1]Y[l+1]+Ĵ*[−1]Y[l−1]+ . . . +Ĵ*[L]Y[l+L]+Ĵ*[−L]Y[l−L].
According to an embodiment of the present disclosure there is provided a plurality of phase tracking reference signal subcarriers, the method including transmitting the orthogonal frequencydivision multiplexed signal, wherein the phase tracking reference signal subcarriers are in a plurality of subcarriers, arranged in N_{c }groups, each of the N_{c }groups including a plurality of adjacent subcarriers.
In one embodiment, each group includes exactly N_{PTRS }adjacent phase tracking reference signal subcarriers, N_{PTRS }being an integer greater than 0.
These and other features and advantages of the present disclosure will be appreciated and understood with reference to the specification, claims, and appended drawings wherein:
The detailed description set forth below in connection with the appended drawings is intended as a description of exemplary embodiments of a system and method for common phase error and intercarrier interference estimation and compensation provided in accordance with the present disclosure and is not intended to represent the only forms in which the present disclosure may be constructed or utilized. The description sets forth the features of the present disclosure in connection with the illustrated embodiments. It is to be understood, however, that the same or equivalent functions and structures may be accomplished by different embodiments that are also intended to be encompassed within the spirit and scope of the disclosure. As denoted elsewhere herein, like element numbers are intended to indicate like elements or features.
An OFDM transmission structure may include a plurality of uniformly spaced subcarriers, e.g., 1024 subcarriers, separated by 15 kHz from each other. Of these subcarriers, a subset, e.g., 600 subcarriers, may be used to transmit data and PTRS subcarriers; this subset may be referred to as the resource block (RB) allocation. The remainder of the subcarriers may be reserved for other purposes such as guard bands. Each subcarrier may be numbered with an index. For example, the subcarriers may be given consecutive numbers beginning with 1 for the lowestfrequency subcarrier or beginning with 1 for the highestfrequency subcarrier in the resource block allocation. The center of the frequency range spanned by the plurality of subcarriers may be at microwave or millimeterwave frequencies, e.g., at 40 GHz or at 60 GHz. Each subcarrier may be independently modulated, e.g., using 8×8 quadrature amplitude modulation (64 QAM) for data subcarriers, and using quadrature phase shift keying (QPSK) modulation for the PTRS subcarriers. Each subcarrier may transmit a stream of symbols (each corresponding to an interval of time). The length of the symbol interval may be selected to be the reciprocal of the spacing between subcarriers (e.g., the symbol interval may be selected to be 1/15,000 seconds) so that each of the subcarriers is orthogonal to all of the other subcarriers during each symbol interval. The New Radio standard uses OFDM.
The frequency domain received signal in the presence of phase noise in each OFDM symbol may be represented as:
Y[l] is the received signal at subcarrier l,
X[k] is the transmitted signal at subcarrier k,
Z[l] is white Gaussian noise,
H[k] is the channel at subcarrier k,
J[k] is the kth term of intercarrier interference,
N is the FFT size, and
θ_{n }is the phase noise realization at time sample n.
In equation 1, J[0] is the common phase error, and, as shown in Equation 1, J[l−k] is intercarrier interference. The channel at subcarrier k, (i.e., the transfer function of the channel, at the center frequency of subcarrier k) may be estimated using a demodulation reference signal (DMRS) that may be transmitted along with data and the PTRS subcarriers.
If θ_{n }is small, the following property may hold for intercarrier interference terms:
J[k]=−J*[−k]
The PTRS structure, i.e., the set of subcarriers used to transmit the PTRS signals, may affect the ability of a receiver to perform interference cancellation, e.g., in particular, the ability of a receiver to compensate for intercarrier interference. Accordingly, in some embodiments a group distributed structure is used. This structure is shown in
κ={k_{11}, . . . , k_{1N}_{PTRS}, . . . , k_{N}_{c}_{1}, . . . , k_{N}_{c}_{N}_{PTRS}}
where k_{pq }is the qth subcarrier of the pth group of subcarriers of the PTRS subcarriers.
When the transmitted data include a group distributed PTRS structure, intercarrier interference estimation and common phase error estimation and compensation may be performed according to two alternate methods, one of which is referred to herein as successive interference cancellation (SIC) and the other of which is referred to as joint estimation of intercarrier interference.
Ĵ[0]=,
and its estimated phase may be calculated, at 205, according to:
Ĵ[0]=((Ĥ[κ]X[κ])^{H}Y[κ])
where
κ is the set of phase tracking reference signal subcarriers,
Ĥ[K] is a diagonal matrix the pth diagonal element of which is equal to the estimated channel response for the pth subcarrier from among the set κ,
X[κ] is the transmitted signal in subcarriers from among the set κ,
Y[κ] is the received signal in subcarriers from among the set κ, and
H as a superscript denotes a conjugate transpose.
Next, a set of L intercarrier interference terms may be iteratively estimated, in a loop including 210 through 235. The value of L providing acceptable performance may depend on N_{PTRS}, on N_{c}, and on the phase noise characteristics. L may be selected offline (e.g., using simulations to identify a value that provides good performance that is relatively insensitive to the phase noise characteristics) and stored in a buffer. At 210, the loop index i is initialized to 1. At 215, a set of PTRS subcarriers suitable for estimating the ith intercarrier interference term is selected. This may be done by defining the following set:
κ_{ij}={k_{1(i+1)}, . . . , k_{1(N}_{PTRS}_{−j)}, . . . , k_{N}_{c}_{(i+1)}, . . . , k_{N}_{c}_{(N}_{PTRS}_{−j)}}
and selecting the set κ_{ii }as the set of PTRS subcarriers to be used for estimating ith intercarrier interference term.
At 220, the estimated common phase error, and the first through (i−1)th intercarrier interference terms may be canceled from the received signal according to:
Y_{SIC}[κ_{ii}]=Y[κ_{ii}]−Ĵ[0]Ĥ[κ_{ii}]X[κ_{ii}],
for i=1
Y_{SIC}[κ_{ii}]=Y[κ_{ii}]−Ĵ[0]Ĥ[κ_{ii}]X[κ_{ii}]−Ĵ[1]Ĥ[κ_{(i−1)(i+1)}]X[κ_{(i−1(i+1)}]
−Ĵ[−1]Ĥ[κ_{(i+1)(i−1)}]X[κ_{(i+1)(i−1)}]− . . . −Ĵ[i−1]Ĥ[κ_{1(2i−1)}]X[κ_{1(2i−1)}]
−Ĵ[−(i−1)]Ĥ[κ_{(2i−1)1}]X[κ_{(2i−1)1}],
for i>1
where
κ_{ij}={k_{1(i+1)}, . . . , k_{1(N}_{PTRS}_{−j)}, . . . , k_{N}_{c}_{(i+1)}, . . . , k_{N}_{c}_{(N}_{PTRS}_{−j)}} (where k_{pq }is the qth subcarrier of the pth group of subcarriers of the phase tracking reference signal subcarriers),
Ĥ[κ_{ij}] is a diagonal matrix the pth diagonal element of which is equal to the estimated channel response for the pth subcarrier from among the set κ_{ij},
X[κ_{pq}] is the transmitted signal in subcarriers from among the set κ_{pq},
Y[κ_{ii}] is the received signal in subcarriers from among the set κ_{ii},
Ĵ[0] is the estimated common phase error, and
Ĵ[p], for p not equal to zero, is the estimated pth intercarrier interference term.
The result, Y_{SIC}[κ_{ii}], may be referred to as the ith compensated received signal.
The next (ith) intercarrier interference term may then be estimated, at 225, based on the ith compensated received signal, according to:
The index i may then be incremented (at 230) and compared to the loop limit L (at 235), and the loop may repeat until i exceeds L.
The estimated common phase error and intercarrier interference terms may then be used to calculate a final compensated received signal Y_{ICI comp}[l] according to:
Y_{ICI comp}[l]=Ĵ*[0]Y[l]+Ĵ*[1]Y[l+1]+Ĵ*[−1]Y[l−1]+ . . . +Ĵ*[L]Y[i+L]+Ĵ*[−L]Y[l−L].
The above expression may be seen to be a finite impulse response (FIR) filter.
Ĵ[0]=,
and calculating the estimated phase according to:
Ĵ[0]=((Ĥ[κ]X[κk])^{H}Y[κ]).
At 310, a set of PTRS subcarriers suitable for jointly estimating the L intercarrier interference terms is selected. This may be done by selecting the set κ_{LL }as the set of PTRS subcarriers to be used for jointly estimating the L intercarrier interference terms. At 315, the common phase error may then be canceled according to
Y_{CPEcomp}[κ_{LL}]=Y[κ_{LL}]−Ĵ[0]Ĥ[κ_{LL}]X[κ_{LL}]
where
κ_{ij}={k_{1(i+1)}, . . . , k_{1(N}_{PTRS}_{−j)}, . . . , k_{N}_{c}_{(i+1)}, . . . , k_{N}_{c}_{(N}_{PTRS}_{−j)}} (where k_{pq }is the qth subcarrier of the p^{th }group of subcarriers of the phase tracking reference signal subcarriers),
Ĥ[κ_{LL}] is a diagonal matrix the p^{th }diagonal element of which is equal to the estimated channel response for the p^{th }subcarrier from among the set κ_{LL},
X[κ_{LL}] is the transmitted signal in subcarriers from among the set κ_{LL},
Y[κ_{LL}] is the received signal in subcarriers from among the set κ_{LL}, and
Ĵ[0] is the estimated common phase error.
At 320, the L intercarrier interference terms may then be estimated jointly according to
the respective ith columns A_{i}, B_{i}, C_{i}, and D_{i }of A, B, C, and D are:
A_{i}=Re{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}−Re{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]};
B_{i}=−Im{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}−Im{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]};
C_{i}=Im{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}−Im{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]}; and
D_{i}=Re{Ĥ[κ_{(L−i)(L+i)}]X[κ_{(L−i)(L+i)}]}+Re{Ĥ[κ_{(L+i)(L−i)}]X[κ_{(L+i)(L−i)}]}.
The estimated common phase error and intercarrier interference terms may then be used to calculate, in the same manner as described above (for the case of intercarrier interference estimation and common phase error estimation and compensation using successive interference cancellation) a final compensated received signal Y_{ICI comp}[l], i.e., according to Y_{ICI comp}[l]=Ĵ*[0]Y[l]+Ĵ*[1]Y[l+1]+Ĵ*[−1]Y[l−1]+ . . . +Ĵ*[L]Y[l+L]+Ĵ*[−L]Y[l−L].
The term “processing circuit” is used herein to mean any combination of hardware, firmware, and software, employed to process data or digital signals. Processing circuit hardware may include, for example, application specific integrated circuits (ASICs), general purpose or special purpose central processing units (CPUs), digital signal processors (DSPs), graphics processing units (GPUs), and programmable logic devices such as field programmable gate arrays (FPGAs). In a processing circuit, as used herein, each function is performed either by hardware configured, i.e., hardwired, to perform that function, or by more general purpose hardware, such as a CPU, configured to execute instructions stored in a nontransitory storage medium. A processing circuit may be fabricated on a single printed circuit board (PCB) or distributed over several interconnected PCBs. A processing circuit may contain other processing circuits; for example a processing circuit may include two processing circuits, an FPGA and a CPU, interconnected on a PCB.
Each of
In
In light of the foregoing, some embodiments include a group distributed PTRS structure to be able to perform intercarrier interference estimation and compensation. Moreover, because the fully distributed PTRS structure with N_{PTRS}=1 is a special case of a group distributed PTRS structure, there may be little or no impact to implementations where only CPE is mitigated. The group distributed PTRS structure may make it possible to handle those phase noise models with wide PSD relative to the subcarrier spacing. The group distributed PTRS structure may also have an advantage over a fully localized PTRS structure which may suffer from a deep fading problem if the allocated PTRS subcarriers are experiencing a poor quality channel condition. Some embodiments further provide a frequency domain successive interference cancellation method and joint method for intercarrier interference estimation, and a frequency domain FIR filter for intercarrier interference compensation that may improve the performance significantly compared to common phase error compensation only.
As used herein, calculating a first value “based on” a second value means calculating the first value as the output of a function the input to which includes the second value. As used herein “canceling” an estimated error from a signal, or “compensating” a signal for an error, means making a correction to a signal based on the estimated error; this need not result in entirely eliminating, from the signal, the effect of the error. As used herein, two subcarriers are “adjacent” if there are no other subcarriers between them in frequency. A group of carriers is referred to as a group of “adjacent subcarriers” if, for every two carriers in the group there are no subcarriers, not in the group, between the two carriers in frequency.
It will be understood that, although the terms “first”, “second”, “third”, etc., may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed herein could be termed a second element, component, region, layer or section, without departing from the spirit and scope of the inventive concept.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the inventive concept. As used herein, the terms “substantially,” “about,” and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent deviations in measured or calculated values that would be recognized by those of ordinary skill in the art. As used herein, the term “major component” refers to a component that is present in a composition, polymer, or product in an amount greater than an amount of any other single component in the composition or product. In contrast, the term “primary component” refers to a component that makes up at least 50% by weight or more of the composition, polymer, or product. As used herein, the term “major portion”, when applied to a plurality of items, means at least half of the items.
As used herein, the singular forms “a” and “an” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising”, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. Expressions such as “at least one of,” when preceding a list of elements, modify the entire list of elements and do not modify the individual elements of the list. Further, the use of “may” when describing embodiments of the inventive concept refers to “one or more embodiments of the present disclosure”. Also, the term “exemplary” is intended to refer to an example or illustration. As used herein, the terms “use,” “using,” “used”, and “approximately” may be considered synonymous with the terms “utilize,” “utilizing,” “utilized,” and “about” respectively.
It will be understood that when an element or layer is referred to as being “on”, “connected to”, “coupled to”, or “adjacent to” another element or layer, it may be directly on, connected to, coupled to, or adjacent to the other element or layer, or one or more intervening elements or layers may be present. In contrast, when an element or layer is referred to as being “directly on”, “directly connected to”, “directly coupled to”, or “immediately adjacent to” another element or layer, there are no intervening elements or layers present.
Although exemplary embodiments of a system and method for phase noise common phase error and intercarrier interference estimation and compensation have been specifically described and illustrated herein, many modifications and variations will be apparent to those skilled in the art. Accordingly, it is to be understood that a system and method for phase error and interference estimation and compensation constructed according to principles of the present disclosure may be embodied other than as specifically described herein. The present disclosure is also defined in the following claims, and equivalents thereof.