CN114079985A - Method and equipment for adjusting carrier frequency - Google Patents
Method and equipment for adjusting carrier frequency Download PDFInfo
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- CN114079985A CN114079985A CN202010820283.XA CN202010820283A CN114079985A CN 114079985 A CN114079985 A CN 114079985A CN 202010820283 A CN202010820283 A CN 202010820283A CN 114079985 A CN114079985 A CN 114079985A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/0005—Control or signalling for completing the hand-off
- H04W36/0055—Transmission or use of information for re-establishing the radio link
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04W—WIRELESS COMMUNICATION NETWORKS
- H04W36/00—Hand-off or reselection arrangements
- H04W36/08—Reselecting an access point
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L27/00—Modulated-carrier systems
- H04L27/0014—Carrier regulation
- H04L2027/0024—Carrier regulation at the receiver end
- H04L2027/0026—Correction of carrier offset
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Abstract
The invention discloses a method and equipment for adjusting carrier frequency, which are used for improving the receiving performance of a terminal. In the cell switching process, the method determines the frequency offset compensation value of the terminal in the target cell according to a first frequency offset value and a second frequency offset value, wherein the first frequency offset value represents the frequency offset value caused by crystal oscillator error, the second frequency offset value represents the frequency offset value caused by Doppler frequency shift, and then the carrier frequency used by the received signal is adjusted according to the frequency offset compensation value. The embodiment of the invention can determine the first frequency offset value caused by crystal oscillator error and the second frequency offset value caused by Doppler frequency shift, and then determine the frequency offset compensation value of the terminal in the target cell according to the first frequency offset value and the second frequency offset value, so that the process of adjusting the frequency offset compensation value is omitted after the terminal is switched to a new cell, and the frequency offset compensation value determined by the terminal is directly used, thereby improving the receiving performance of the terminal.
Description
Technical Field
The present invention relates to the field of wireless communications technologies, and in particular, to a method and a device for adjusting a carrier frequency.
Background
In high-speed rail, multiple antennas in the same cell are generally deployed along the high-speed rail by Radio Remote Unit (RRH), so that cell coverage is increased, switching frequency is reduced, and network performance is improved.
After the terminal on the high-speed rail performs cell switching, the terminal needs to estimate the frequency offset compensation value again in order not to affect the receiving performance of the terminal.
Estimating the frequency offset compensation value generally adopts the following two modes, namely, resetting the historical frequency offset compensation value, starting adaptive adjustment from 0, and adjusting to the frequency offset compensation value with the best terminal receiving performance; and secondly, based on the historical frequency offset compensation value of the source cell, starting adaptive adjustment from the historical frequency offset compensation value of the source cell until the frequency offset compensation value with the best terminal receiving performance is obtained.
In the prior art, in the process of adjusting the frequency offset compensation value, the receiving performance of the terminal is affected because the frequency offset compensation value is inaccurate.
Disclosure of Invention
The invention provides a method and equipment for adjusting carrier frequency, which are used for solving the problem that the receiving performance of a terminal is poor in the process of adjusting a frequency offset compensation value after the terminal performs cell switching in the prior art.
In a first aspect, an embodiment of the present application provides a method for adjusting a carrier frequency, where the method includes:
the method comprises the steps that a terminal determines a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value in the process of cell switching, wherein the first frequency offset value represents a frequency offset value caused by crystal oscillator errors, and the second frequency offset value represents a frequency offset value caused by Doppler frequency shift;
and the terminal adjusts the carrier frequency used by the received signal according to the frequency offset compensation value.
In a possible implementation manner, the determining, by the terminal, a frequency offset compensation value of the terminal in the target cell, further includes:
and the terminal determines the first frequency offset value and the second frequency offset value according to the frequency offset value on each path in the source cell, wherein each path is a path corresponding to each RRH in the source cell.
In a possible implementation manner, the determining, by the terminal, the first frequency offset value according to the frequency offset value on each path in the source cell includes:
the terminal determines the difference value of the frequency offset values of any two paths in the source cell;
the terminal determines a first path and a second path corresponding to the difference value with the maximum absolute value from all the determined difference values;
and the terminal determines the first frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path.
In a possible implementation manner, the determining, by the terminal, the first frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path includes:
and the terminal takes the average value of the frequency offset value on the first path and the frequency offset value on the second path as the first frequency offset value.
In a possible implementation manner, the determining, by the terminal, the second frequency offset value according to the frequency offset value on each path in the source cell includes:
the terminal makes a difference between the average value of the frequency deviation values on each path and the first frequency deviation value to obtain a third frequency deviation value, wherein the third frequency deviation value represents the frequency deviation value caused by Doppler frequency shift on each path;
and the terminal takes the inverse number of the third frequency offset value as the second frequency offset value.
In a possible implementation manner, the determining, by the terminal, a frequency offset compensation value of the terminal in the target cell according to the first frequency offset value and the second frequency offset value includes:
and the terminal takes the sum of the first frequency offset value and the second frequency offset value as a frequency offset compensation value of the terminal in a target cell.
In a second aspect, an embodiment of the present application provides a terminal device, including:
a memory to store instructions;
a processor for reading the instructions in the memory, performing the following processes:
in the process of cell switching, determining a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value, wherein the first frequency offset value represents a frequency offset value caused by crystal oscillator errors, and the second frequency offset value represents a frequency offset value caused by Doppler frequency shift;
and adjusting the carrier frequency used by the received signal according to the frequency offset compensation value.
In one possible implementation, the processor is further configured to:
before determining a frequency offset compensation value of the terminal in a target cell, determining the first frequency offset value and the second frequency offset value according to a frequency offset value on each path in a source cell, wherein each path is a path corresponding to each RRH in the source cell.
In one possible implementation, the processor is specifically configured to:
determining the difference value of the frequency offset values of any two paths in the source cell;
determining a first path and a second path corresponding to the difference value with the maximum absolute value from all the determined difference values;
and determining the first frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path.
In one possible implementation, the processor is specifically configured to:
and taking the average value of the frequency offset value on the first path and the frequency offset value on the second path as the first frequency offset value.
In one possible implementation, the processor is specifically configured to:
the terminal makes a difference between the average value of the frequency deviation values on each path and the first frequency deviation value to obtain a third frequency deviation value, wherein the third frequency deviation value represents the frequency deviation value caused by Doppler frequency shift on each path;
and the terminal takes the inverse number of the third frequency offset value as the second frequency offset value.
In one possible implementation, the processor is specifically configured to:
and taking the sum of the first frequency offset value and the second frequency offset value as a frequency offset compensation value of the terminal in the target cell.
In a third aspect, an embodiment of the present application provides another terminal device, including:
a determining module, configured to determine, during a cell handover process, a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value, where the first frequency offset value represents a frequency offset value caused by a crystal oscillator error, and the second frequency offset value represents a frequency offset value caused by a doppler frequency shift;
and the adjusting module is used for adjusting the carrier frequency used by the received signal according to the frequency offset compensation value.
In one possible implementation, the determining module is further configured to:
and the terminal determines the first frequency offset value and the second frequency offset value according to the frequency offset value on each path in the source cell, wherein each path is a path corresponding to each RRH in the source cell.
In a possible implementation manner, the determining module is specifically configured to:
determining the difference value of the frequency offset values of any two paths in the source cell;
determining a first path and a second path corresponding to the difference value with the maximum absolute value from all the determined difference values;
and determining the first frequency offset value and the second frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path.
In a possible implementation manner, the determining module is specifically configured to:
and the terminal takes the average value of the frequency offset value on the first path and the frequency offset value on the second path as the first frequency offset value.
In a possible implementation manner, the determining module is specifically configured to:
the terminal makes a difference between the average value of the frequency deviation values on each path and the first frequency deviation value to obtain a third frequency deviation value, wherein the third frequency deviation value represents the frequency deviation value caused by Doppler frequency shift on each path;
and the terminal takes the inverse number of the third frequency offset value as the second frequency offset value.
In a possible implementation manner, the determining module is specifically configured to:
and the terminal takes the sum of the first frequency offset value and the second frequency offset value as a frequency offset compensation value of the terminal in a target cell.
A fourth aspect provides a computer storage medium storing computer software instructions for a terminal device as described in the second aspect or a terminal device as described in the third aspect and comprising a program designed for a terminal device to perform any one of the possible designs of the first aspect or the first aspect.
In the cell switching process, the frequency offset compensation value of the terminal in the target cell is determined according to the first frequency offset value and the second frequency offset value, wherein the first frequency offset value represents a frequency offset value caused by crystal oscillator errors, the second frequency offset value represents a frequency offset value caused by Doppler frequency shift, and then the carrier frequency used by the received signal is adjusted according to the frequency offset compensation value. The embodiment of the invention can determine the first frequency offset value caused by crystal oscillator error and the second frequency offset value caused by Doppler frequency shift, and then determine the frequency offset compensation value of the terminal in the target cell according to the first frequency offset value and the second frequency offset value, so that the process of adjusting the frequency offset compensation value is omitted after the terminal is switched to a new cell, and the frequency offset compensation value determined by the terminal is directly used, thereby improving the receiving performance of the terminal.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a diagram illustrating the change of doppler shift of signals of different RRHs with time;
fig. 2 is a schematic diagram of a terminal performing cell handover according to an embodiment of the present invention;
fig. 3 is a flowchart of a method for adjusting carrier frequency according to an embodiment of the present invention;
fig. 4 is a schematic diagram of a path corresponding to an RRH according to an embodiment of the present invention;
fig. 5 is a schematic diagram of a terminal located at a position intermediate between RRH0 and RRH 1;
fig. 6 is a schematic diagram of terminals located at one side of RRH0 and RRH 1;
fig. 7 is a flowchart illustrating an overall method for adjusting a carrier frequency according to an embodiment of the present invention;
FIG. 8 is a diagram illustrating frequency offset convergence;
FIG. 9 is a graph of throughput with and without frequency offset;
FIG. 10 is a graph showing SNR measurements at different signal strengths;
fig. 11 is a schematic structural diagram of a terminal device according to an embodiment of the present invention;
fig. 12 is a schematic structural diagram of another terminal device according to an embodiment of the present invention.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
In order to make the technical solutions of the present disclosure better understood by those of ordinary skill in the art, the technical solutions in the embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings.
It should be noted that the terms "first," "second," and the like in the description and claims of the present invention and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the invention described herein are capable of operation in sequences other than those illustrated or described herein. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with the present invention. Rather, they are merely examples of apparatus and methods consistent with certain aspects of the invention, as detailed in the appended claims.
Some terms appearing herein are explained below:
1. the term "and/or" in the embodiments of the present invention describes an association relationship of associated objects, and indicates that three relationships may exist, for example, a and/or B may indicate: a exists alone, A and B exist simultaneously, and B exists alone. The character "/" generally indicates that the former and latter associated objects are in an "or" relationship.
2. A terminal device, also called a User Equipment (UE), a Mobile Station (MS), a Mobile Terminal (MT), etc., is a device that provides voice and/or data connectivity to a user, for example, a handheld device with a wireless connection function, a vehicle-mounted device, etc. Currently, some examples of terminals are: a mobile phone (mobile phone), a tablet computer, a notebook computer, a palm top computer, a Mobile Internet Device (MID), a wearable device, a Virtual Reality (VR) device, an Augmented Reality (AR) device, a wireless terminal in industrial control (industrial control), a wireless terminal in self driving (self driving), a wireless terminal in remote surgery (remote medical supply), a wireless terminal in smart grid (smart grid), a wireless terminal in transportation safety (smart security), a wireless terminal in city (smart city), a wireless terminal in home (smart home), and the like.
3. The Network side device may be a RAN (Radio Access Network) node or a base station. The RAN is the part of the network that accesses the terminal to the wireless network. A RAN node (or device) is a node (or device) in a radio access network, which may also be referred to as a base station. Currently, some examples of RAN nodes are: a 5G base station (gbb), a Transmission Reception Point (TRP), an evolved Node B (eNB), a Radio Network Controller (RNC), a Node B (NB), a Base Station Controller (BSC), a Base Transceiver Station (BTS), a home base station (e.g., home evolved Node B or home Node B, HNB), a Base Band Unit (BBU), or a wireless fidelity (Wifi) Access Point (AP), etc. In addition, in one network configuration, the RAN may include a Centralized Unit (CU) node and a Distributed Unit (DU) node.
4. Remote Radio Unit (RRH) is a technology for converting baseband signals into optical signals for transmission and amplification at a Remote end. The RRH technology is characterized in that a base station can be divided into a wireless baseband control (radio Server) part and a radio remote part. The wireless device part can be independently remotely set, and then a network can be flexibly constructed.
The network architecture and the service scenario described in the embodiment of the present invention are for more clearly illustrating the technical solution of the embodiment of the present invention, and do not form a limitation on the technical solution provided in the embodiment of the present invention, and it can be known by those skilled in the art that the technical solution provided in the embodiment of the present invention is also applicable to similar technical problems along with the evolution of the network architecture and the appearance of a new service scenario.
In order to make the objects, technical solutions and advantages of the present invention clearer, the present invention will be described in further detail with reference to the accompanying drawings, and it is apparent that the described embodiments are only a part of the embodiments of the present invention, not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
A terminal on a high-speed rail may receive signals from multiple different RRHs of the same cell, and the doppler shift of the signals from the different RRHs varies with time, as shown in fig. 1.
As can be seen from fig. 1, as the distance between the terminal and the RRH changes, the doppler shift of the signals of different RRHs also changes, for example, for RRH1, when the distance between the terminal and RRH1 is 1000m, the doppler shift of the signal of RRH1 is 200 Hz.
When the terminal performs cell handover, the terminal may be located on the same side of the RRH in the source cell, as shown in fig. 2, which is a schematic diagram of the terminal performing cell handover according to the embodiment of the present invention.
In fig. 2, RRH0 and RRH1 are RRHs in a source cell before handover of a terminal, and RRH2 and RRH3 are RRHs in a target cell after handover of the terminal. As can be seen in fig. 2, the terminal is located between RRH1 and RRH 2.
At the time shown in FIG. 2, suppose the terminal (UE) is affected by RRH0 and RRH1 and the Doppler frequency shift results in the frequency offset fdFrequency offset caused by crystal oscillation error of terminal (UE) is foWhen the cell is switched, the total frequency offset value to be compensated by the terminal (UE) self-adaptive frequency offset compensation module (AFC) is fCFO＝fd+fo。
Since the angles between the incoming wave directions of RRH0, RRH1, RRH2 and RRH3 and the motion direction of the high-speed rail are approximately opposite, it can be considered that the frequency offset caused by the doppler shift of the terminal (UE) affected by RRH2 and RRH3 during handover is-fd。
However, in the prior art, when cell handover occurs, frequency offset f caused by doppler shift cannot be estimated separatelydFrequency deviation f caused by crystal oscillation error of terminaloTherefore, the terminal cannot estimate the total frequency offset value to be compensated in the target cell, and the terminal can only perform adaptive adjustment from 0 or the total frequency offset value to be compensated in the source cell, and finally adjust to the total frequency offset value to be compensated in the target cell.
Based on the above problem, as shown in fig. 3, an embodiment of the present invention provides a method for adjusting a carrier frequency, where the method includes:
s301, in the process of cell switching, a terminal determines a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value, wherein the first frequency offset value represents a frequency offset value caused by a crystal oscillator error, and the second frequency offset value represents a frequency offset value caused by Doppler frequency shift;
s302, the terminal adjusts the carrier frequency used by the received signal according to the frequency offset compensation value.
In the cell switching process, the frequency offset compensation value of the terminal in the target cell is determined according to the first frequency offset value and the second frequency offset value, wherein the first frequency offset value represents a frequency offset value caused by crystal oscillator errors, the second frequency offset value represents a frequency offset value caused by Doppler frequency shift, and then the carrier frequency used by the received signal is adjusted according to the frequency offset compensation value. The embodiment of the invention can determine the first frequency offset value caused by crystal oscillator error and the second frequency offset value caused by Doppler frequency shift, and then determine the frequency offset compensation value of the terminal in the target cell according to the first frequency offset value and the second frequency offset value, so that the process of adjusting the frequency offset compensation value is omitted after the terminal is switched to a new cell, and the frequency offset compensation value determined by the terminal is directly used, thereby improving the receiving performance of the terminal.
The invention can respectively estimate the frequency offset value f caused by Doppler frequency shift according to the frequency offset value estimated on each path of the source celldFrequency offset value f caused by crystal oscillator erroro. When cell switching occurs, the compensation value of an adaptive frequency offset compensation module (AFC) is directly switched to-fd+foTherefore, after switching, the frequency offset can be quickly converged to an accurate value.
In implementation, the terminal may determine the first frequency offset value and the second frequency offset value according to a frequency offset value on each path in the source cell, where each path is a path corresponding to each RRH in the source cell.
It should be noted that, the path corresponding to each RRH in the source cell is an effective path whose power is greater than a preset threshold.
Because the positions of the RRHs are different, signals from the RRHs received by the terminal have certain delay differences, namely, the terminal (UE) can see different paths when measuring and estimating.
Fig. 4 is a schematic diagram of a path corresponding to an RRH according to an embodiment of the present invention. As can be seen in fig. 4, path 0 corresponds to RRH0 and path 1 corresponds to RRH 1.
For example, there are 3 RRHs in the source cell, which are RRH0, RRH1, RRH2, the corresponding diameters of the RRHs are diameter 0, diameter 1, and diameter 2, respectively, and when the terminal determines the first frequency offset value and the second frequency offset value, it needs to determine the frequency offset values on diameter 0, diameter 1, and diameter 2.
When determining the first frequency offset value and the second frequency offset value, the terminal may determine in the process of cell handover performed by the terminal, or may determine before cell handover performed by the terminal.
The specific method for the terminal to determine the first frequency offset value may be: in the moving process of the terminal, firstly determining the frequency offset value on each path in the source cell, then determining the difference value of the frequency offset values of any two paths in the source cell, then determining a first path and a second path corresponding to the maximum difference value of absolute values from all the determined difference values, and finally determining the first frequency offset value according to the frequency offset values on the first path and the second path.
For example, there are 3 RRHs in the source cell, which are RRH0, RRH1, RRH2, the corresponding diameters of the RRHs are diameter 0, diameter 1, and diameter 2, respectively, the frequency offset value on diameter 0 is 200Hz, the frequency offset value on diameter 1 is 300Hz, the frequency offset value on diameter 2 is 150Hz, the three frequency offset values are differed pairwise, and finally, the two diameters with the largest difference value are determined as diameter 1 and diameter 2.
Specifically, the average value of the frequency offset values on the first path and the second path corresponding to the difference value with the largest absolute value may be used as the first frequency offset value, that is, the frequency offset value caused by the crystal oscillator error.
For example, the two paths with the largest absolute value of the frequency offset difference are path 1 and path 2, the frequency offset value on path 1 is 300Hz, the frequency offset value on path 2 is 150Hz, and the mean value of the frequency offset values on path 1 and path 2 is 225Hz, that is, the frequency offset value caused by the crystal oscillator error is 225 Hz.
As shown in fig. 5, the terminal is located between RRH0 and RRH 1.
Under the source cell, when a terminal (UE) is located between RRH0 and RRH1, since the incoming wave directions of RRH0 and RRH1 are approximately opposite to the high-speed rail moving direction, therefore,
at this time, the frequency deviation between the diameter 0 and the diameter 1 is
The sum of the frequency deviations on path 0 and path 1 is f0+f1≈2·fo. That is, when the terminal is located in the middle of two RRHs, the absolute value of the frequency offset on the two paths is the largest.
Determining the frequency offset value caused by the crystal oscillator error, and obtaining a frequency offset estimation value caused by the crystal oscillator error by approximately separating the frequency offset sum of the two corresponding paths by dividing the frequency offset sum by 2 when the absolute value of the frequency offset difference value from the two paths is maximum in the motion process of the statistical terminal (UE)
Since the frequency offset caused by the crystal oscillator error generally does not change very quickly, when the cell handover occurs, the frequency offset caused by the crystal oscillator error can be considered to be still
Specifically, when the second frequency offset value is determined, in the process of switching the cell, the frequency offset values on each path may be counted, then the mean value of the frequency offset values on each path is determined, the mean value is subtracted from the frequency offset value caused by the crystal oscillator error to obtain the frequency offset value caused by the doppler shift on each path, and finally, the obtained opposite number of the frequency offset value caused by the doppler shift on each path is used as the second frequency offset value.
Since the terminal is about to perform cell handover, the terminal has moved to the same side of the RRH in the source cell. As shown in fig. 6, since the angles between the incoming wave directions of RRH0 and RRH1 and the moving direction of the high-speed rail are approximately equal, therefore,
at this time, the frequency deviation between the diameter 0 and the diameter 1 is f0-f 10 is approximately distributed; the sum of the frequency offsets on path 0 and path 1 is
Frequency offset value caused by Doppler shift on path 0 or path 1
Then in the target cell, the frequency offset value caused by the doppler shift is
After the first frequency offset value and the second frequency offset value are determined, the sum of the first frequency offset value and the second frequency offset value may be used as a frequency offset compensation value of the terminal in the target cell.
The initial value of frequency offset compensation is
In the invention, after the terminal is switched to a new cell, the frequency offset can be initialized to an accurate value, namely a frequency offset compensation value. Therefore, even at the time of cell switching, normal reception performance can be ensured.
Furthermore, the present invention is applicable to all Orthogonal Frequency Division Multiplexing (OFDM) systems.
In addition, when the different cell measurement is carried out, the method of the invention can also be applied, thereby avoiding the problem of inaccurate different cell measurement caused by frequency offset compensation errors.
Fig. 7 is a flowchart illustrating an overall method for adjusting a carrier frequency according to an embodiment of the present invention.
S701, a terminal estimates frequency offset values on all paths in a source cell;
s702, the terminal obtains a frequency deviation estimated value caused by crystal oscillator error by approximately separating the frequency deviation value obtained by dividing the sum of the frequency deviation values on the two corresponding paths by 2 when the absolute value of the frequency deviation difference value on the two paths is maximum in the motion process of the terminal through statistics
S703, the terminal counts the cell switching processCalculating the frequency offset value caused by Doppler frequency shift
S704, according to
And
calculating frequency deviation compensation initial value f under new cellnew；
S705, the terminal is according to fnewThe carrier frequency used for receiving the signal is adjusted.
The present invention is further illustrated by the following specific embodiments.
Example 1:
taking a 5G system as an example, assuming that the carrier frequency is 3.0GHz, the crystal oscillator error is 3ppm (3 ppm), and the terminal moving speed is 350km/h, the frequency offset caused by the crystal oscillator error is 3e-6 × 3.0e9 — 9000 Hz; the doppler shift results in a frequency offset of 350/3.6/3.0e8 × 3.0e9 — 972.22 Hz. Theoretically, the total frequency offset when a cell handover occurs is 9000-972.22-8027.78 Hz.
When cell switching occurs, the invention can quickly converge to an accurate total frequency offset value; in the prior art (taking the historical frequency offset value of the original cell as an example), the convergence needs at least 10 to 50 time slots due to the limitation of the pilot frequency (TRS) periodicity and the step length adjustment of the adaptive frequency offset compensation module (AFC) each time, as shown in fig. 8.
As shown in fig. 9, the performance under "no frequency offset" is better than the performance under "500 Hz frequency offset" by taking 5G, 15kHz subcarrier spacing, 10M bandwidth, dual stream, adaptive CQI feedback, no retransmission, and 500Hz frequency offset as examples; the higher the SNR (signal-to-noise ratio), the higher the corresponding modulation scheme, the greater the influence of frequency offset, and therefore the greater the performance difference.
Example 2:
taking the 5G system as an example, under the measurement of the different cells, it is assumed that the RRHs of the different cells are all located at one side of the terminal (UE). Then, under the different cell measurement, corresponding etc. can be assumedThe effective frequency offset compensation initial value is
The method can quickly determine the total frequency offset value during the measurement of the different cells; in the prior art (taking a historical frequency offset value from an original cell as an example), the used frequency offset is greatly different from the true frequency offset, so that a large error exists in the measurement of the different cell, as shown in fig. 10.
Based on the same inventive concept, the embodiment of the present invention further provides a terminal device, and since the principle of the terminal device for solving the problem is similar to the method for adjusting the carrier frequency in the embodiment of the present invention, the implementation of the terminal device may refer to the implementation of the method, and repeated details are not repeated.
As shown in fig. 11, a terminal device provided in an embodiment of the present invention includes: a processor 1100, a memory 1101, a transceiver 1102, and a bus interface.
The processor 1100 is responsible for managing the bus architecture and general processing, and the memory 1101 may store data used by the processor 1100 in performing operations. The transceiver 1102 is used to receive and transmit data under the control of the processor 1100.
The bus architecture may include any number of interconnected buses and bridges, with various circuits specifically represented by one or more of processor 1100 and memory represented by memory 1101 linked together. The bus architecture may also link together various other circuits such as peripherals, voltage regulators, power management circuits, and the like, which are well known in the art, and therefore, will not be described any further herein. The bus interface provides an interface. The processor 1100 is responsible for managing the bus architecture and general processing, and the memory 1101 may store data used by the processor 1100 in performing operations.
The process disclosed by the embodiment of the invention can be applied to the processor 200, or implemented by the processor 200. In implementation, the steps of the signal processing flow may be implemented by integrated logic circuits of hardware or instructions in the form of software in the processor 200. The processor 1100 may be a general-purpose processor, a digital signal processor, an application specific integrated circuit, a field programmable gate array or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or the like that implement or perform the methods, steps, and logic blocks disclosed in embodiments of the present invention. A general purpose processor may be a microprocessor or any conventional processor or the like. The steps of a method disclosed in connection with the embodiments of the present invention may be directly implemented by a hardware processor, or may be implemented by a combination of hardware and software modules in the processor. The software module may be located in ram, flash memory, rom, prom, or eprom, registers, etc. storage media as is well known in the art. The storage medium is located in the memory 1101, and the processor 1100 reads information in the memory 1101, and completes the steps of the signal processing flow in combination with hardware thereof.
Specifically, the processor 1100 is configured to read a program in the memory 1101 and execute:
in the process of cell switching, determining a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value, wherein the first frequency offset value represents a frequency offset value caused by crystal oscillator errors, and the second frequency offset value represents a frequency offset value caused by Doppler frequency shift;
and adjusting the carrier frequency used by the received signal according to the frequency offset compensation value.
Optionally, the processor 1100 is further configured to:
before determining a frequency offset compensation value of the terminal in a target cell, determining the first frequency offset value and the second frequency offset value according to a frequency offset value on each path in a source cell, wherein each path is a path corresponding to each RRH in the source cell.
Optionally, the processor 1100 is specifically configured to:
determining the difference value of the frequency offset values of any two paths in the source cell;
determining a first path and a second path corresponding to the difference value with the maximum absolute value from all the determined difference values;
and determining the first frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path.
Optionally, the processor 1100 is specifically configured to:
and taking the average value of the frequency offset value on the first path and the frequency offset value on the second path as the first frequency offset value.
Optionally, the processor 1100 is specifically configured to:
the terminal makes a difference between the average value of the frequency deviation values on each path and the first frequency deviation value to obtain a third frequency deviation value, wherein the third frequency deviation value represents the frequency deviation value caused by Doppler frequency shift on each path;
and the terminal takes the inverse number of the third frequency offset value as the second frequency offset value.
Optionally, the processor 1100 is specifically configured to:
and taking the sum of the first frequency offset value and the second frequency offset value as a frequency offset compensation value of the terminal in the target cell.
As shown in fig. 12, another terminal device provided in the embodiment of the present invention includes:
a determining module 1200, configured to determine, during a cell handover process, a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value, where the first frequency offset value represents a frequency offset value caused by a crystal oscillator error, and the second frequency offset value represents a frequency offset value caused by a doppler shift;
and an adjusting module 1201, configured to adjust a carrier frequency used by the received signal according to the frequency offset compensation value.
Optionally, the determining module 1200 is further configured to:
and the terminal determines the first frequency offset value and the second frequency offset value according to the frequency offset value on each path in the source cell, wherein each path is a path corresponding to each RRH in the source cell.
Optionally, the determining module 1200 is specifically configured to:
determining the difference value of the frequency offset values of any two paths in the source cell;
determining a first path and a second path corresponding to the difference value with the maximum absolute value from all the determined difference values;
and determining the first frequency offset value and the second frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path.
Optionally, the determining module 1200 is specifically configured to:
and the terminal takes the average value of the frequency offset value on the first path and the frequency offset value on the second path as the first frequency offset value.
Optionally, the determining module 1200 is specifically configured to:
the terminal makes a difference between the average value of the frequency deviation values on each path and the first frequency deviation value to obtain a third frequency deviation value, wherein the third frequency deviation value represents the frequency deviation value caused by Doppler frequency shift on each path;
and the terminal takes the inverse number of the third frequency offset value as the second frequency offset value.
Optionally, the determining module 1200 is specifically configured to:
and the terminal takes the sum of the first frequency offset value and the second frequency offset value as a frequency offset compensation value of the terminal in a target cell.
Further, an embodiment of the present invention further provides a computer storage medium, where computer program instructions are stored, and when the instructions are run on a computer, the instructions cause the computer to perform the steps of the method for adjusting the carrier frequency.
As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.
The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.
These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present application without departing from the spirit and scope of the application. Thus, if such modifications and variations of the present application fall within the scope of the claims of the present application and their equivalents, the present application is intended to include such modifications and variations as well.
Claims (14)
1. A method of adjusting a carrier frequency, the method comprising:
the method comprises the steps that a terminal determines a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value in the process of cell switching, wherein the first frequency offset value represents a frequency offset value caused by crystal oscillator errors, and the second frequency offset value represents a frequency offset value caused by Doppler frequency shift;
and the terminal adjusts the carrier frequency used by the received signal according to the frequency offset compensation value.
2. The method of claim 1, wherein the terminal determines that the terminal is prior to the frequency offset compensation value of the target cell, further comprising:
and the terminal determines the first frequency offset value and the second frequency offset value according to the frequency offset value on each path in the source cell, wherein each path is a path corresponding to each radio remote unit (RRH) in the source cell.
3. The method of claim 2, wherein the determining, by the terminal, the first frequency offset value according to the frequency offset value on each path in the source cell comprises:
the terminal determines the difference value of the frequency offset values of any two paths in the source cell;
the terminal determines a first path and a second path corresponding to the difference value with the maximum absolute value from all the determined difference values;
and the terminal determines the first frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path.
4. The method of claim 3, wherein the terminal determining the first frequency offset value based on the frequency offset value on the first path and the frequency offset value on the second path comprises:
and the terminal takes the average value of the frequency offset value on the first path and the frequency offset value on the second path as the first frequency offset value.
5. The method of claim 4, wherein the terminal determines the second frequency offset value according to the frequency offset value on each path in the source cell, comprising:
the terminal makes a difference between the average value of the frequency deviation values on each path and the first frequency deviation value to obtain a third frequency deviation value, wherein the third frequency deviation value represents the frequency deviation value caused by Doppler frequency shift on each path;
and the terminal takes the inverse number of the third frequency offset value as the second frequency offset value.
6. The method as claimed in any of claims 1 to 5, wherein the determining, by the terminal, the frequency offset compensation value of the terminal in the target cell according to the first frequency offset value and the second frequency offset value comprises:
and the terminal takes the sum of the first frequency offset value and the second frequency offset value as a frequency offset compensation value of the terminal in a target cell.
7. A terminal device, comprising:
a memory to store instructions;
a processor for reading the instructions in the memory, performing the following processes:
in the process of cell switching, determining a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value, wherein the first frequency offset value represents a frequency offset value caused by crystal oscillator errors, and the second frequency offset value represents a frequency offset value caused by Doppler frequency shift;
and adjusting the carrier frequency used by the received signal according to the frequency offset compensation value.
8. The device of claim 7, wherein the processor is further configured to:
before determining a frequency offset compensation value of the terminal in a target cell, determining the first frequency offset value and the second frequency offset value according to a frequency offset value on each path in a source cell, wherein each path is a path corresponding to each RRH in the source cell.
9. The device of claim 8, wherein the processor is specifically configured to:
determining the difference value of the frequency offset values of any two paths in the source cell;
determining a first path and a second path corresponding to the difference value with the maximum absolute value from all the determined difference values;
and determining the first frequency offset value according to the frequency offset value on the first path and the frequency offset value on the second path.
10. The device of claim 9, wherein the processor is specifically configured to:
and taking the average value of the frequency offset value on the first path and the frequency offset value on the second path as the first frequency offset value.
11. The device of claim 10, wherein the processor is specifically configured to:
the terminal makes a difference between the average value of the frequency deviation values on each path and the first frequency deviation value to obtain a third frequency deviation value, wherein the third frequency deviation value represents the frequency deviation value caused by Doppler frequency shift on each path;
and the terminal takes the inverse number of the third frequency offset value as the second frequency offset value.
12. The apparatus of any of claims 7 to 11, wherein the processor is specifically configured to:
and taking the sum of the first frequency offset value and the second frequency offset value as a frequency offset compensation value of the terminal in the target cell.
13. A terminal device, comprising:
a determining module, configured to determine, during a cell handover process, a frequency offset compensation value of the terminal in a target cell according to a first frequency offset value and a second frequency offset value, where the first frequency offset value represents a frequency offset value caused by a crystal oscillator error, and the second frequency offset value represents a frequency offset value caused by a doppler frequency shift;
and the adjusting module is used for adjusting the carrier frequency used by the received signal according to the frequency offset compensation value.
14. A computer storage medium having stored therein instructions that, when executed on a computer, cause the computer to perform the method of any one of claims 1-6.
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| CN202010820283.XA CN114079985A (en) | 2020-08-14 | 2020-08-14 | Method and equipment for adjusting carrier frequency |
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| CN117527497A (en) * | 2024-01-05 | 2024-02-06 | 中国电力科学研究院有限公司 | Frequency offset calibration method, device, electronic equipment and storage medium |
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