CN106685623B - Time delay compensation method, user equipment and base station - Google Patents

Time delay compensation method, user equipment and base station Download PDF

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CN106685623B
CN106685623B CN201611067482.8A CN201611067482A CN106685623B CN 106685623 B CN106685623 B CN 106685623B CN 201611067482 A CN201611067482 A CN 201611067482A CN 106685623 B CN106685623 B CN 106685623B
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antenna port
time delay
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CN106685623A (en
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周宝龙
胡宏杰
朱有团
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Huawei Technologies Co Ltd
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
    • H04L5/00—Arrangements affording multiple use of the transmission path
    • H04L5/003—Arrangements for allocating sub-channels of the transmission path
    • H04L5/0048—Allocation of pilot signals, i.e. of signals known to the receiver
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04B—TRANSMISSION
    • H04B7/00—Radio transmission systems, i.e. using radiation field
    • H04B7/02—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas
    • H04B7/04—Diversity systems; Multi-antenna system, i.e. transmission or reception using multiple antennas using two or more spaced independent antennas
    • H04B7/0413—MIMO systems
    • H04B7/0456—Selection of precoding matrices or codebooks, e.g. using matrices antenna weighting
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W28/00—Network traffic management; Network resource management
    • H04W28/02—Traffic management, e.g. flow control or congestion control
    • H04W28/0231—Traffic management, e.g. flow control or congestion control based on communication conditions
    • H04W28/0236—Traffic management, e.g. flow control or congestion control based on communication conditions radio quality, e.g. interference, losses or delay
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04W—WIRELESS COMMUNICATION NETWORKS
    • H04W56/00—Synchronisation arrangements
    • H04W56/0055—Synchronisation arrangements determining timing error of reception due to propagation delay

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Abstract

The embodiment of the invention discloses a time delay compensation method, user equipment and a base station, which can reduce the channel time delay of each antenna port so as to improve the gain of a codebook. The method provided by the embodiment of the invention comprises the following steps: user Equipment (UE) receives downlink pilot frequency sent by a base station through at least two antenna ports; the UE carries out time delay measurement according to the downlink pilot frequency to obtain channel time delay of each antenna port; when the UE sends the channel delay to the base station, the UE carries out delay compensation on a downlink baseband channel according to the channel delay to obtain the downlink baseband channel after delay compensation; the UE performs Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after the time delay compensation to obtain a codebook vector; and the UE sends the codebook vector to the base station.

Description

Time delay compensation method, user equipment and base station
Technical Field
The present invention relates to the field of communications technologies, and in particular, to a delay compensation method, a user equipment, and a base station.
Background
Fifth Generation mobile communication (5 th-Generation, 5G) high frequency employs Hybrid Beamforming (HBF) technology to transmit data. There are two beamforming methods, one is beamforming based on reciprocity between uplink and downlink of Time Division Duplex (TDD), and the other is based on codebook vector fed back by User Equipment (UE). In 5G high frequency, there are different delays when signals transmitted by each antenna port of the base station reach the UE, which may cause that a Precoding Matrix Index (PMI) selected by the UE is not completely matched with an actual transmission channel, thereby reducing codebook gain. Therefore, the UE needs to measure and feed back the channel delay of each antenna port of the base station, and feed back the channel delay to the base station, so that the base station performs delay compensation before downlink data transmission.
In the existing scheme, a subband feedback technology is generally adopted for delay compensation.
However, in 5G high frequency, if the subband feedback technique is still used, the subband bandwidth needs to be greatly reduced, and the feedback overhead is greatly increased due to the large bandwidth of the 5G high frequency, so the delay compensation method adopted by the existing scheme is not suitable.
Disclosure of Invention
The embodiment of the invention provides a time delay compensation method, user equipment and a base station, which can reduce the channel time delay of each antenna port so as to improve the gain of a codebook.
A first aspect of an embodiment of the present invention provides a delay compensation method, which may include: a base station sends downlink pilot frequency to User Equipment (UE) through at least two antenna ports, wherein the downlink pilot frequency can be but is not limited to CSI pilot frequency, beam scanning pilot frequency and the like; after the UE receives the downlink pilot frequency, the UE performs time delay measurement according to the received downlink pilot frequency, and channel time delay of each antenna port is obtained through the time delay measurement; on one hand, the UE sends the channel delay to the base station, and on the other hand, the UE performs delay compensation on the downlink baseband channel according to the channel delay to obtain the downlink baseband channel after the delay compensation; then, the UE carries out PMI measurement according to the downlink baseband channel after time delay compensation to obtain a codebook vector; finally, the UE sends the codebook vector to the base station. Therefore, the UE carries out time delay measurement based on the downlink pilot frequency to obtain the channel time delay of each antenna port, the UE carries out time delay compensation on the downlink baseband channel, and finally carries out PMI measurement based on the downlink baseband channel after time delay compensation to obtain a codebook vector, and the codebook vector is sent to the base station, so that the base station uses the codebook vector to carry out weighting processing on data sent to the UE, the channel time delay of each antenna port is reduced, and the codebook gain is improved.
In some possible implementation manners, the UE performs least square channel estimation according to the received downlink pilot frequency, and performs delay measurement according to the least square channel to obtain the channel delay of each antenna port. The least squares channel may be a frequency domain least squares channel, or a time domain least squares channel. That is, the UE may directly measure the channel delay of each antenna port in the frequency domain by using the frequency domain least square channel, or may convert the frequency domain least square channel into the time domain least square channel and measure the channel delay of each antenna port by using the time domain power delay spectrum.
In other possible implementation manners, the UE calculates, according to the channel delay, a phase shift of each target antenna port relative to a reference antenna port on a subcarrier where each pilot frequency is located, where each target antenna port and the reference antenna port constitute the at least two antenna ports, that is, assuming that at least two antenna ports are antenna port 1, antenna port 2, and antenna port 3, each target antenna port may be antenna port 1 and antenna port 2, and then the reference antenna port is antenna port 3; the UE makes phase shift into a preset vector; and the UE performs time delay compensation on the downlink baseband channel according to the preset vector.
In other possible implementations, the phase shift of the target antenna port relative to the reference antenna port on the subcarrier where each pilot is located is generated according to the following formula:
Figure BDA0001164065620000021
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure BDA0001164065620000022
in order to shift the phase of the signal,
Figure BDA0001164065620000023
for the target antenna port TRXiRelative reference antenna port TRX1K is TRXiNumber of sub-carrier where the ith pilot position is located, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
In other possible implementations, the preset vector is the following vector:
Figure BDA0001164065620000024
wherein, deltalIs a preset vector.
In other possible implementations, the delay compensated downlink baseband channel is obtained by the following formula
Figure BDA0001164065620000025
Wherein ⊙ represents a dot product, heff,1(l) Represents the downlink baseband channel before delay compensation (delta)k)*Representing a predetermined vector deltalConjugation of (1).
A second aspect of the embodiments of the present invention provides a delay compensation method, which may include: a base station sends downlink pilot frequency to User Equipment (UE) through at least two antenna ports, wherein the downlink pilot frequency can be but is not limited to CSI pilot frequency, beam scanning pilot frequency and the like; the UE carries out time delay measurement according to the received downlink pilot frequency to obtain channel time delay of each antenna port, the UE sends the channel time delay to the base station, the UE carries out time delay compensation on a downlink baseband channel according to the channel time delay to obtain the downlink baseband channel after the time delay compensation, the UE carries out PMI measurement according to the downlink baseband channel after the time delay compensation to obtain a first codebook vector, and the first codebook vector is sent to the base station; after receiving the channel delay and the first codebook vector, the base station performs delay compensation on the downlink baseband channel according to the channel delay and the first codebook vector to obtain a second codebook vector after delay compensation. Therefore, the base station performs delay compensation on the downlink baseband channel according to the channel delay and the received first codebook vector to obtain a second codebook vector after the delay compensation, and the base station can perform precoding weighting processing on data sent to the UE by using the second codebook vector, so that the channel delay of each antenna port is reduced, and the codebook gain is improved.
In some possible implementation manners, the base station calculates the phase shift of each target antenna port relative to a reference antenna port on each subcarrier according to the channel delay, and each target antenna port and the reference antenna port form at least two antenna ports, that is, assuming that at least two antenna ports are antenna port 1, antenna port 2 and antenna port 3, each target antenna port may be antenna port 1 and antenna port 2, and then the reference antenna port is antenna port 3; the base station makes phase shift into a preset vector; and the base station performs time delay compensation on the downlink baseband channel according to the preset vector and the first codebook vector to obtain a second codebook vector after time delay compensation.
In other possible implementations, the phase shift of the target antenna port relative to the reference antenna port on each subcarrier is generated according to the following formula:
Figure BDA0001164065620000031
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure BDA0001164065620000032
is the target antenna port TRXiRelative reference antenna port TRX1K is the number of the sub-carrier, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
At this time, the preset vector is as follows:
Figure BDA0001164065620000033
wherein, deltakIs a preset vector.
In other possible implementations, the delay compensated second codebook vector w 'is obtained by'm(k):
Figure BDA0001164065620000041
Wherein ⊙ represents a dot product, (δ)k)*Representing a predetermined vector deltakConjugation of (a) wmRepresenting a first codebook vector of a codebook of,
Figure BDA0001164065620000042
according to the technical scheme, the embodiment of the invention has the following advantages: the user equipment carries out time delay measurement based on the downlink pilot frequency to obtain channel time delay of each antenna port, carries out time delay compensation on a downlink baseband channel, carries out PMI measurement based on the downlink baseband channel after time delay compensation to obtain a codebook vector, and sends the codebook vector to the base station, so that the base station uses the codebook vector to carry out weighting processing on data sent to the UE, thereby reducing the channel time delay of each antenna port and improving the codebook gain.
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FIG. 1 is a schematic diagram of a delay compensation method according to an embodiment of the present invention;
fig. 2 is a schematic diagram of an embodiment of a delay compensation method according to an embodiment of the present invention;
fig. 3 is a schematic diagram of an embodiment of a user equipment UE in the embodiment of the present invention;
fig. 4 is a schematic diagram of another embodiment of a user equipment UE in the embodiment of the present invention;
fig. 5 is a schematic diagram of an embodiment of a base station in the embodiment of the present invention;
fig. 6 is a schematic diagram of another embodiment of the base station in the embodiment of the present invention.
Detailed Description
The embodiment of the invention provides a time delay compensation method, user equipment and a base station, which can reduce the channel time delay of each antenna port so as to improve the gain of a codebook.
The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.
The terms "first," "second," "third," "fourth," and the like in the description and in the claims, as well as in the drawings, if any, are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It will be appreciated that the data so used may be interchanged under appropriate circumstances such that the embodiments described herein may be practiced otherwise than as specifically illustrated or described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Referring to fig. 1, fig. 1 is a schematic diagram illustrating a principle of a delay compensation method according to an embodiment of the present invention. In fig. 1, a base station transmits downlink pilot frequency, such as Channel State Information (CSI) pilot frequency, beam scanning pilot frequency, etc., to a UE. The UE may perform Least Square (LS) channel estimation based on such downlink pilot, and then perform delay measurement based on the LS channel estimation. And after the channel delay of each antenna port is obtained, the UE performs delay compensation on the downlink baseband channel, and finally performs PMI measurement based on the downlink baseband channel after delay compensation. Meanwhile, the UE needs to feed back the measured delay of each antenna port to the base station. After obtaining the time delay of each antenna port, the base station also needs to perform time delay compensation, and then can perform precoding weighting on the user data sent to the UE.
Referring to fig. 2, a method for compensating for a delay in an embodiment of the present invention is described below with reference to a specific embodiment, where an embodiment of the method for compensating for a delay in an embodiment of the present invention includes:
101. a base station sends downlink pilot frequency to User Equipment (UE) through at least two antenna ports;
in this embodiment, the downlink pilot may be, but is not limited to, a CSI pilot, a beam scanning pilot, and the like.
102. The UE performs time delay measurement according to the downlink pilot frequency to obtain channel time delay of each antenna port, and then respectively executes step 103 and step 106;
optionally, in some possible embodiments, the UE performs delay measurement according to the downlink pilot frequency, and the channel delay of each antenna port obtained may be:
and the UE carries out least square channel estimation according to the downlink pilot frequency and carries out time delay measurement according to the least square channel to obtain the channel time delay of each antenna port.
Further, the least square channel may be a frequency domain least square channel or a time domain least square channel.
It should be understood that the UE may measure the channel Delay of each antenna port in the frequency domain directly by using a frequency domain least square channel, or may convert the frequency domain least square channel into a time domain least square channel and measure the channel Delay of each antenna port by using a time domain Power Delay spectrum (hereinafter, referred to as "Power Delay Profile"). Of course, the present invention may also adopt other ways to measure the channel delay, and is not limited herein.
103. The UE carries out time delay compensation on the downlink baseband channel according to the channel time delay to obtain the downlink baseband channel after the time delay compensation;
optionally, in some possible embodiments, the performing, by the UE, delay compensation on the downlink baseband channel according to the channel delay may be:
the UE calculates the phase shift of each target antenna port relative to a reference antenna port on the subcarrier where each pilot frequency is located according to the channel delay, and each target antenna port and the reference antenna port form at least two antenna ports;
the UE makes phase shift into a preset vector;
and the UE performs time delay compensation on the downlink baseband channel according to the preset vector.
Further, the phase shift of the target antenna port relative to the reference antenna port on the subcarrier where each pilot frequency is located is generated according to the following formula:
Figure BDA0001164065620000061
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure BDA0001164065620000062
in order to shift the phase of the signal,
Figure BDA0001164065620000063
for the target antenna port TRXiRelative reference antenna port TRX1K is TRXiNumber of sub-carrier where the ith pilot position is located, NIFFTFor IFFT length, NTxAntenna port representing a base stationAnd (4) the number.
At this time, the preset vector is as follows:
Figure BDA0001164065620000064
wherein, deltalIs a preset vector.
Further, the UE performs delay compensation on the downlink baseband channel according to the preset vector, and the downlink baseband channel after the delay compensation is obtained may be:
obtaining a downlink baseband channel H 'after time delay compensation through the following formula'eff(l)：
Figure BDA0001164065620000065
Wherein ⊙ represents a dot product, heff,1(l) Represents the downlink baseband channel before delay compensation (delta)k)*Representing a predetermined vector deltalConjugation of (1).
104. The UE performs Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after time delay compensation to obtain a first codebook vector;
105. the UE sends the first codebook vector to a base station;
106. the UE sends the channel delay to the base station;
107. and the base station performs time delay compensation on the downlink baseband channel according to the channel time delay and the first codebook vector to obtain a second codebook vector after the time delay compensation.
In this embodiment, the user equipment performs delay measurement based on the downlink pilot frequency to obtain channel delay of each antenna port, performs delay compensation on the downlink baseband channel, and finally performs PMI measurement based on the downlink baseband channel after delay compensation to obtain a codebook vector, and sends the codebook vector to the base station, so that the base station performs weighting processing on data sent to the UE by using the codebook vector, thereby reducing the channel delay of each antenna port and improving codebook gain.
Optionally, in some possible embodiments, the base station performs delay compensation on the downlink baseband channel according to the channel delay and the first codebook vector, and the second codebook vector after the delay compensation is obtained may be:
the base station calculates the phase shift of each target antenna port on each subcarrier relative to the reference antenna port according to the channel time delay, and each target antenna port and the reference antenna port form at least two antenna ports;
the base station makes phase shift into a preset vector;
and the base station performs time delay compensation on the downlink baseband channel according to the preset vector and the first codebook vector to obtain a second codebook vector after time delay compensation.
Further, the phase shift of the target antenna port relative to the reference antenna port on each subcarrier is generated according to the following formula:
Figure BDA0001164065620000071
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure BDA0001164065620000072
is the target antenna port TRXiRelative reference antenna port TRX1K is the number of the sub-carrier, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
At this time, the preset vector is as follows:
Figure BDA0001164065620000073
wherein, deltakIs a preset vector.
Further, the base station performs delay compensation on the downlink baseband channel according to the preset vector and the first codebook vector, and the second codebook vector after the delay compensation is obtained is:
obtaining a time delay compensated second codebook vector w 'by the following formula'm(k):
Figure BDA0001164065620000074
Wherein ⊙ represents a dot product, (δ)k)*Representing a predetermined vector deltakConjugation of (a) wmRepresenting a first codebook vector of a codebook of,
Figure BDA0001164065620000081
the method for compensating for the delay in the embodiment of the present invention is described above by an embodiment, and the user equipment UE in the embodiment of the present invention is described below by an embodiment.
Referring to fig. 3, an embodiment of a user equipment UE according to the embodiment of the present invention includes:
a receiving module 201, configured to receive downlink pilot sent by a base station through at least two antenna ports;
a first processing module 202, configured to perform time delay measurement according to the downlink pilot frequency to obtain channel time delays of each antenna port;
a first sending module 203, configured to send the channel delay to the base station;
a second processing module 204, configured to perform delay compensation on the downlink baseband channel according to the channel delay when the first sending module 203 sends the channel delay to the base station, so as to obtain a downlink baseband channel after delay compensation;
a third processing module 205, configured to perform precoding matrix index PMI measurement according to the downlink baseband channel after delay compensation, to obtain a codebook vector;
a second sending module 206, configured to send the codebook vector to the base station.
In this embodiment, the first processing module 202 performs delay measurement based on the downlink pilot frequency to obtain channel delay of each antenna port, the second processing module 204 performs delay compensation on the downlink baseband channel, and finally the third processing module 205 performs PMI measurement based on the downlink baseband channel after delay compensation to obtain a codebook vector, and sends the codebook vector to the base station, so that the base station uses the codebook vector to perform weighting processing on data sent to the UE, thereby reducing channel delay of each antenna port and improving codebook gain.
In some optional embodiments of the present invention, the first processing module 202 is specifically configured to perform least square channel estimation according to a downlink pilot frequency, and perform delay measurement according to a least square channel, so as to obtain a channel delay of each antenna port.
Further, the least square channel may be a frequency domain least square channel or a time domain least square channel.
It should be understood that the first processing module 202 may measure the channel delay of each antenna port directly in the frequency domain by using a frequency domain least square channel, or may convert the frequency domain least square channel into a time domain least square channel and measure the channel delay of each antenna port by using a PDP. Of course, the present invention may also adopt other ways to measure the channel delay, and is not limited herein.
In some optional embodiments of the present invention, the second processing module 204 is specifically configured to calculate, according to the channel delay, a phase shift of each target antenna port relative to a reference antenna port on a subcarrier where each pilot frequency is located, where each target antenna port and the reference antenna port form at least two antenna ports; phase shift is combined into a preset vector; and performing time delay compensation on the downlink baseband channel according to a preset vector.
Further, the second processing module 204 is specifically configured to generate a phase shift of the target antenna port relative to the reference antenna port on the subcarrier where each pilot is located according to the following formula:
Figure BDA0001164065620000091
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure BDA0001164065620000092
in order to shift the phase of the signal,
Figure BDA0001164065620000093
for the target antenna port TRXiRelative reference antenna port TRX1Is k isTRXiNumber of sub-carrier where the ith pilot position is located, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
Further, the preset vector is as follows:
Figure BDA0001164065620000094
wherein, deltalIs a preset vector.
Further, the second processing module 204 is specifically configured to obtain the downlink baseband channel H 'after delay compensation according to the following formula'eff(l)：
Figure BDA0001164065620000095
Wherein ⊙ represents a dot product, heff,1(l) Represents the downlink baseband channel before delay compensation (delta)k)*Representing a predetermined vector deltalConjugation of (1).
In the above, the UE in the embodiment of the present invention is described from the perspective of the modular functional entity, and in the following, the UE in the embodiment of the present invention is described from the perspective of hardware processing, referring to fig. 4, where the UE in the embodiment of the present invention includes: a receiver 301, a processor 302, a transmitter 303, and a memory 304.
The user equipment UE to which embodiments of the present invention relate may have more or fewer components than shown in fig. 4, may combine two or more components, or may have a different configuration or arrangement of components, each of which may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.
The receiver 301 is configured to perform the following operations:
and receiving downlink pilot frequency sent by the base station through at least two antenna ports.
The processor 302 is configured to perform the following operations:
and measuring time delay according to the downlink pilot frequency to obtain the channel time delay of each antenna port.
The transmitter 303 is configured to perform the following operations:
and sending the channel time delay to the base station.
The processor 302 is further configured to perform the following operations:
when the transmitter 303 sends the channel delay to the base station, performing delay compensation on the downlink baseband channel according to the channel delay to obtain a downlink baseband channel after delay compensation; and performing Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after time delay compensation to obtain a codebook vector.
The transmitter 303 is also configured to perform the following operations:
the codebook vector is transmitted to the base station.
The memory 304 is used for storing codes required by the processor 302 to perform corresponding operations.
In this embodiment, the processor 302 performs delay measurement based on the downlink pilot frequency to obtain channel delay of each antenna port, performs delay compensation on the downlink baseband channel, and finally performs PMI measurement based on the downlink baseband channel after delay compensation to obtain a codebook vector, and sends the codebook vector to the base station, so that the base station performs weighting processing on data sent to the UE by using the codebook vector, thereby reducing the channel delay of each antenna port and improving codebook gain.
The processor 302 is further configured to perform the following operations:
and performing least square channel estimation according to the downlink pilot frequency, and performing time delay measurement according to the least square channel to obtain the channel time delay of each antenna port.
The processor 302 is further configured to perform the following operations:
calculating the phase shift of each target antenna port relative to the reference antenna port on the subcarrier where each pilot frequency is located according to the channel time delay, wherein each target antenna port and the reference antenna port form the at least two antenna ports; phase shift is combined into a preset vector; and performing time delay compensation on the downlink baseband channel according to a preset vector.
The user equipment UE in the embodiment of the present invention is described above by an embodiment, and the base station in the embodiment of the present invention is described below by an embodiment.
Referring to fig. 5, an embodiment of a base station in the embodiment of the present invention includes:
a sending module 401, configured to send downlink pilot to a user equipment UE through at least two antenna ports;
a receiving module 402, configured to receive a channel delay sent by the UE, where the channel delay is obtained by the UE performing delay measurement according to the received downlink pilot frequency, and the channel delay of each antenna port is obtained;
the processing module 403 is configured to perform delay compensation on the downlink baseband channel according to the channel delay and the received first codebook vector to obtain a second codebook vector after delay compensation, where the first codebook vector is obtained by performing precoding matrix index PMI measurement on the downlink baseband channel after delay compensation by the UE.
In this embodiment, the processing module 403 performs delay compensation on the downlink baseband channel according to the channel delay and the received first codebook vector to obtain a second codebook vector after the delay compensation, and the processing module 403 may perform precoding weighting processing on data sent to the UE by using the second codebook vector, so as to reduce the channel delay of each antenna port and improve the codebook gain.
In some optional embodiments of the present invention, the processing module 403 is specifically configured to calculate, according to the channel delay, a phase shift of each target antenna port on each subcarrier relative to a reference antenna port, where each target antenna port and the reference antenna port form the at least two antenna ports; phase shift is combined into a preset vector; and performing time delay compensation on the downlink baseband channel according to the preset vector and the received first codebook vector to obtain a second codebook vector after time delay compensation.
Further, the processing module 403 is specifically configured to generate a phase shift of the target antenna port relative to the reference antenna port on each subcarrier according to the following formula:
Figure BDA0001164065620000111
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure BDA0001164065620000112
is the target antenna port TRXiRelative reference antenna port TRX1K is the number of the sub-carrier, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
The preset vector is as follows:
Figure BDA0001164065620000113
wherein, deltakIs a preset vector.
Further, the processing module 403 is specifically configured to obtain a second codebook vector w 'after time delay compensation according to the following formula'm(k)：
Figure BDA0001164065620000114
Wherein ⊙ represents a dot product, (δ)k)*Representing a predetermined vector deltakConjugation of (a) wmRepresenting a first codebook vector of a codebook of,
Figure BDA0001164065620000115
in the above, the base station in the embodiment of the present invention is described from the perspective of the modular functional entity, and in the following, the base station in the embodiment of the present invention is described from the perspective of hardware processing, referring to fig. 6, and the base station in the embodiment of the present invention includes: a transmitter 501, a receiver 502, a processor 503, and a memory 504.
Embodiments of the invention may involve a base station having more or fewer components than those shown in fig. 6, two or more components may be combined, or a different configuration or arrangement of components, and each component may be implemented in hardware, software, or a combination of hardware and software, including one or more signal processing and/or application specific integrated circuits.
The transmitter 501 is configured to perform the following operations:
and sending the downlink pilot frequency to the user equipment UE through at least two antenna ports.
The receiver 502 is configured to perform the following operations:
and receiving channel time delay sent by the UE, wherein the channel time delay is the channel time delay of each antenna port obtained by the UE performing time delay measurement according to the received downlink pilot frequency.
The processor 503 is configured to perform the following operations:
and performing time delay compensation on the downlink baseband channel according to the channel time delay and the received first codebook vector to obtain a second codebook vector after the time delay compensation, wherein the first codebook vector is obtained by the UE performing Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after the time delay compensation.
The memory 504 is used for storing codes required by the processor 502 to perform corresponding operations.
In this embodiment, the processor 503 performs delay compensation on the downlink baseband channel according to the channel delay and the received first codebook vector to obtain a second codebook vector after the delay compensation, and the processor 503 may perform precoding weighting processing on data sent to the UE by using the second codebook vector, thereby reducing the channel delay of each antenna port and improving the codebook gain.
The processor 503 is further configured to perform the following operations:
calculating the phase shift of each target antenna port relative to a reference antenna port on each subcarrier according to the channel time delay, wherein each target antenna port and the reference antenna port form the at least two antenna ports; phase shift is combined into a preset vector; and performing time delay compensation on the downlink baseband channel according to the preset vector and the received first codebook vector to obtain a second codebook vector after time delay compensation.
It is clear to those skilled in the art that, for convenience and brevity of description, the specific working processes of the above-described systems, apparatuses and units may refer to the corresponding processes in the foregoing method embodiments, and are not described herein again.
In the several embodiments provided in the present application, it should be understood that the disclosed system, apparatus and method may be implemented in other manners. For example, the above-described apparatus embodiments are merely illustrative, and for example, the division of the units is only one logical division, and other divisions may be realized in practice, for example, a plurality of units or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection through some interfaces, devices or units, and may be in an electrical, mechanical or other form.
The units described as separate parts may or may not be physically separate, and parts displayed as units may or may not be physical units, may be located in one place, or may be distributed on a plurality of network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of the embodiment.
In addition, functional units in the embodiments of the present invention may be integrated into one processing unit, or each unit may exist alone physically, or two or more units are integrated into one unit. The integrated unit can be realized in a form of hardware, and can also be realized in a form of a software functional unit.
The integrated unit, if implemented in the form of a software functional unit and sold or used as a stand-alone product, may be stored in a computer readable storage medium. Based on such understanding, the technical solution of the present invention may be embodied in the form of a software product, which is stored in a storage medium and includes instructions for causing a computer device (which may be a personal computer, a server, or a network device) to execute all or part of the steps of the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.
The above-mentioned embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; and such modifications or substitutions do not depart from the spirit and scope of the corresponding technical solutions of the embodiments of the present invention.

Claims (24)

1. A method of delay compensation, comprising:
user Equipment (UE) receives downlink pilot frequency sent by a base station through at least two antenna ports;
the UE carries out time delay measurement according to the downlink pilot frequency to obtain channel time delay of each antenna port;
when the UE sends the channel delay to the base station, the UE carries out delay compensation on a downlink baseband channel according to the channel delay to obtain the downlink baseband channel after delay compensation;
the UE performs Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after the time delay compensation to obtain a first codebook vector;
and the UE sends the first codebook vector to the base station, and the channel delay and the first codebook vector are used for indicating the base station to perform delay compensation on a downlink baseband channel to obtain a second codebook vector after delay compensation.
2. The method of claim 1, wherein the UE performs the delay measurement according to the downlink pilot, and obtaining the channel delay of each antenna port comprises:
and the UE carries out least square channel estimation according to the downlink pilot frequency and carries out time delay measurement according to the least square channel to obtain the channel time delay of each antenna port.
3. The method of claim 2, wherein the least squares channel is a frequency domain least squares channel or a time domain least squares channel.
4. The method of any one of claims 1 to 3, wherein the UE performing delay compensation on the downlink baseband channel according to the channel delay comprises:
the UE calculates the phase shift of each target antenna port relative to a reference antenna port on the subcarrier where each pilot frequency is located according to the channel time delay, and each target antenna port and the reference antenna port form at least two antenna ports;
the UE enables the phase shifts to form preset vectors;
and the UE performs time delay compensation on the downlink baseband channel according to the preset vector.
5. The method of claim 4, wherein the phase shift of the target antenna port relative to the reference antenna port on the sub-carrier where each pilot is located is generated according to the following formula:
Figure FDA0002262736880000011
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure FDA0002262736880000012
in order to shift the phase of the signal,
Figure FDA0002262736880000013
for the target antenna port TRXiRelative reference antenna port TRX1K is TRXiNumber of sub-carrier where the ith pilot position is located, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
6. The method of claim 5, wherein the predetermined vector is the following vector:
Figure FDA0002262736880000021
wherein, deltalIs a preset vector.
7. The method according to claim 6, wherein the UE performs delay compensation on the downlink baseband channel according to the preset vector, and the downlink baseband channel after delay compensation is obtained as follows:
obtaining a downlink baseband channel H 'after time delay compensation through the following formula'eff(l)：
Figure FDA0002262736880000022
Wherein e represents dot product, Heff(l) Represents the downlink baseband channel before delay compensation (delta)l)*Representing a predetermined vector deltalConjugation of (1).
8. A method of delay compensation, comprising:
a base station sends downlink pilot frequency to User Equipment (UE) through at least two antenna ports;
the base station receives channel time delay sent by the UE, wherein the channel time delay is the channel time delay of each antenna port obtained by the UE performing time delay measurement according to the received downlink pilot frequency;
and the base station performs time delay compensation on the downlink baseband channel according to the channel time delay and the received first codebook vector to obtain a second codebook vector after time delay compensation, wherein the first codebook vector is obtained by the UE performing Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after time delay compensation.
9. The method of claim 8, wherein the base station performs delay compensation on the downlink baseband channel according to the channel delay and the received first codebook vector, and obtaining a second codebook vector after delay compensation comprises:
the base station calculates the phase shift of each target antenna port relative to a reference antenna port on each subcarrier according to the channel time delay, and each target antenna port and the reference antenna port form at least two antenna ports;
the base station makes the phase shift into a preset vector;
and the base station performs time delay compensation on the downlink baseband channel according to the preset vector and the received first codebook vector to obtain a second codebook vector after time delay compensation.
10. The method of claim 9, wherein the phase shift of the target antenna port relative to the reference antenna port on each subcarrier is generated according to the following equation:
Figure FDA0002262736880000031
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure FDA0002262736880000032
is the target antenna port TRXiRelative reference antenna port TRX1K is the number of the sub-carrier, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
11. The method of claim 10, wherein the predetermined vector is the following vector:
Figure FDA0002262736880000033
wherein, deltakTo a predetermined vectorAmount of the compound (A).
12. The method of claim 11, wherein the base station performs delay compensation on a downlink baseband channel according to the preset vector and the received first codebook vector, and a second codebook vector after the delay compensation is obtained is:
obtaining a time delay compensated second codebook vector w 'by the following formula'm(k)：
Figure FDA0002262736880000034
Wherein e represents a dot product, (δ)k)*Representing a predetermined vector deltakConjugation of (a) wmRepresenting a first codebook vector of a codebook of,
Figure FDA0002262736880000035
13. a User Equipment (UE), comprising:
a receiving module, configured to receive downlink pilot sent by a base station through at least two antenna ports;
the first processing module is used for carrying out time delay measurement according to the downlink pilot frequency to obtain the channel time delay of each antenna port;
a first sending module, configured to send the channel delay to the base station;
the second processing module is used for performing time delay compensation on a downlink baseband channel according to the channel time delay when the first sending module sends the channel time delay to the base station, so as to obtain the downlink baseband channel after time delay compensation;
the third processing module is used for performing Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after the time delay compensation to obtain a first codebook vector;
and a second sending module, configured to send the first codebook vector to the base station, where the channel delay and the first codebook vector are used to instruct the base station to perform delay compensation on a downlink baseband channel, so as to obtain a second codebook vector after delay compensation.
14. The UE of claim 13, wherein the first processing module is specifically configured to perform least square channel estimation according to the downlink pilot, and perform delay measurement according to the least square channel to obtain a channel delay of each antenna port.
15. The UE of claim 14, wherein the least squares channel is a frequency domain least squares channel or a time domain least squares channel.
16. The UE according to any one of claims 13 to 15, wherein the second processing module is specifically configured to calculate, according to the channel delay, a phase shift of each target antenna port on a subcarrier where each pilot frequency is located relative to a reference antenna port, where each target antenna port and the reference antenna port constitute the at least two antenna ports; forming the phase shift into a preset vector; and performing time delay compensation on the downlink baseband channel according to the preset vector.
17. The UE of claim 16, wherein the second processing module is specifically configured to generate a phase shift of the target antenna port relative to the reference antenna port on the subcarrier where each pilot is located according to the following formula:
Figure FDA0002262736880000041
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure FDA0002262736880000042
in order to shift the phase of the signal,
Figure FDA0002262736880000043
for the target antenna port TRXiRelative reference antenna port TRX1K is TRXiNumber of sub-carrier where the ith pilot position is located, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
18. The UE of claim 17, wherein the predetermined vector is as follows:
Figure FDA0002262736880000044
wherein, deltalIs a preset vector.
19. The UE of claim 18, wherein the second processing module is specifically configured to obtain a delay-compensated downlink baseband channel H 'according to the following formula'eff(l)：
Figure FDA0002262736880000045
Wherein e represents dot product, Heff(l) Represents the downlink baseband channel before delay compensation (delta)l)*Representing a predetermined vector deltalConjugation of (1).
20. A base station, comprising:
a sending module, configured to send downlink pilot to user equipment UE through at least two antenna ports;
a receiving module, configured to receive a channel delay sent by the UE, where the channel delay is obtained by the UE performing delay measurement according to the received downlink pilot frequency, and the channel delay of each antenna port is obtained;
and the processing module is used for performing time delay compensation on a downlink baseband channel according to the channel time delay and the received first codebook vector to obtain a second codebook vector after the time delay compensation, wherein the first codebook vector is obtained by the UE performing Precoding Matrix Index (PMI) measurement according to the downlink baseband channel after the time delay compensation.
21. The base station of claim 20, wherein the processing module is specifically configured to calculate, according to the channel delay, a phase shift of each target antenna port on each subcarrier relative to a reference antenna port, where each target antenna port and the reference antenna port form the at least two antenna ports; forming the phase shift into a preset vector; and performing time delay compensation on the downlink baseband channel according to the preset vector and the received first codebook vector to obtain a second codebook vector after time delay compensation.
22. The base station of claim 21, wherein the processing module is specifically configured to generate the phase shift of the target antenna port relative to the reference antenna port on each subcarrier according to the following formula:
Figure FDA0002262736880000051
wherein, TRXiFor the target antenna port, TRX1For reference to the antenna port(s),
Figure FDA0002262736880000052
is the target antenna port TRXiRelative reference antenna port TRX1K is the number of the sub-carrier, NIFFTFor IFFT length, NTxIndicating the number of antenna ports of the base station.
23. The base station of claim 22, wherein the predetermined vector is as follows:
Figure FDA0002262736880000053
wherein, deltakIs a preset vector.
24. Root of herbaceous plantThe base station of claim 23, wherein the processing module is specifically configured to obtain the delay compensated second codebook vector w 'according to the following formula'm(k)：
Figure FDA0002262736880000054
Wherein e represents a dot product, (δ)k)*Representing a predetermined vector deltakConjugation of (a) wmRepresenting a first codebook vector of a codebook of,
Figure FDA0002262736880000055
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