WO2018137479A1

WO2018137479A1 - Method and device for generating digital beamforming codebook

Info

Publication number: WO2018137479A1
Application number: PCT/CN2018/070763
Authority: WO
Inventors: 徐国珍; 左君; 王爱玲; 韩双锋
Original assignee: 中国移动通信有限公司研究院; 中国移动通信集团有限公司
Priority date: 2017-01-26
Filing date: 2018-01-04
Publication date: 2018-08-02
Also published as: CN108365876A

Abstract

Disclosed in an embodiment of the present invention are a method and device for generating a digital beamforming codebook. The method comprises: acquiring currently adopted analog beamforming information; and generating, according to the analog beamforming information, a digital beamforming codebook.

Description

Digital beamforming codebook generating method and device

Cross-reference to related applications

The present application claims priority to the Chinese Patent Office, filed on Jan. 26, 2017, the entire disclosure of which is hereby incorporated by reference.

Technical field

The present disclosure relates to the field of communications technologies, and in particular, to a digital beamforming codebook generating method and apparatus.

Background technique

In the current 3GPP standardization process, hybrid beamforming (Hybrid Beamforming) scheme will be adopted in consideration of factors such as equipment cost. In order to ensure large network coverage and improve beamforming gain, the beamwidth of the analog beam in hybrid beamforming is usually narrower, thereby concentrating the transmit power. For the corresponding digital beamforming, a fixed codebook scheme is adopted, and the user selects a corresponding codeword from the fixed codebook as a PMI (Precoding Matrix Indicator) feedback to assist the base station to complete the digital beam. Forming.

In the related art, a pre-generated fixed digital codebook is used to cover the entire angular space (or phase space), and the UE selects the most suitable codeword for current beamforming by comparing the codewords in the codebook ( Or PMI feedback), the program has the characteristics of low complexity. However, for 5G NR systems, especially in high-band systems, analog beamforming greatly limits the range of beam coverage due to hybrid beamforming techniques; in addition, due to the high direct-current characteristics of high-frequency communications ( LOS channel), if a uniform fixed digital codebook is used, the number of digital beams covered for a narrow analog beam is extremely small, which will greatly limit the accuracy of digital beamforming and reduce the digital beamforming gain.

In the 5G pass high frequency signal, the Rice channel state is more obvious. Since the system adopts hybrid beamforming, the generated beam state can be represented as shown in Figures 1, 2 and 3. 1 shows analog beamforming, and FIGS. 2 and 3 show digital beamforming, wherein the range in which the digital beam 3 is shaped in FIGS. 2 and 3 is limited to analog beamforming.

In the case of a wide analog beam, the analog beam (such as the wider beam 1 in Figure 1) covers a sufficient number of digital beams, but uses the same digital beam if it is in a narrower digital beam (Figure 1). In the narrower beam 2), the number of digital beams under the analog beam is extremely small, which greatly limits the gain of digital beamforming.

Summary of the invention

The technical problem to be solved by the present disclosure is to provide a digital beamforming codebook generating method and apparatus. The codebook of the digital beam within the analog beam can be dynamically generated to increase the digital beamforming gain.

In order to solve the above technical problem, an embodiment of the present disclosure provides the following solution:

A digital beamforming codebook generating method includes:

Obtaining information about the currently used analog beamforming;

A shaped codebook of the digital beam is generated based on the information of the analog beamforming.

The generating the codebook of the digital beam further includes:

From the shaped codebook of the digital beam, a digital beamforming codeword that matches the current channel is selected.

Wherein, after selecting the digital beamforming codeword that matches the current channel, the method further includes:

The selected current channel matched digital beamforming codeword is fed back to the base station.

The steps of obtaining the currently used analog beamforming information include:

Obtain the information of the analog beamforming currently used for the sounding reference signal SRS configuration.

The information of the analog beamforming includes: width information of the analog beam, information about the rotation direction of the analog beam, and the number of digital ports.

The step of generating a shaped codebook of the digital beam according to the information of the analog beamforming includes:

Ranking the information of the analog beamforming to obtain a rank number;

A shaped codebook of the digital beam is generated based on the rank number.

The step of generating a shaped codebook of the digital beam according to the rank number includes:

Determining a phase space dimension of the beam according to the rank number;

Obtaining a signal strength of the phase space dimension;

A shaped codebook of the digital beam is generated based on the signal strength of the phase space dimension.

The step of generating a shaped codebook of the digital beam according to the signal strength of the phase space dimension includes:

For a phase space dimension in which the signal strength of the phase space dimension is greater than the first preset value, a codeword that is more than the second preset value is allocated to generate a shaped codebook of the digital beam.

The step of selecting a digital beamforming codeword that matches the current channel from the shaped codebook of the digital beam includes:

According to the formula:

Selecting, from the shaped codebook V of the digital beam, a codeword v whose direction is closest to the ideal beamforming vector w; wherein

A beamforming vector representing a codebook.

An embodiment of the present disclosure further provides a digital beamforming codebook generating apparatus, including:

An acquisition module, configured to obtain information about the currently used analog beamforming;

And a generating module, configured to generate a shaped codebook of the digital beam according to the information of the analog beamforming.

The digital beamforming codebook generating device further includes:

And a selection module, configured to select, from the shaped codebook of the digital beam, a digital beamforming codeword that matches the current channel.

The digital beamforming codebook generating device further includes:

And a feedback module, configured to feed back the selected digital beamforming codeword of the current channel to the base station.

The acquiring module is specifically configured to: obtain information about the simulated beamforming used by the current sounding reference signal SRS configuration.

The generating module is specifically configured to: rank the information of the analog beamforming to obtain a rank number; and generate a shaped codebook of the digital beam according to the rank number.

After the obtaining the rank number, the generating module is specifically configured to: determine a phase space dimension of the beam according to the rank number; acquire a signal strength of the phase space dimension; generate a number according to the signal strength of the phase space dimension The shaped codebook of the beam.

The generating module is configured to: when generating a codebook of the digital beam according to the signal strength of the phase space dimension, specifically:

The selection module is specifically configured to:

According to the formula:

From the shaped codebook V of the digital beam, select the direction

The codeword v closest to the ideal beamforming vector w;

A beamforming vector representing a codebook.

An embodiment of the present disclosure further provides a digital beamforming codebook generating apparatus, including a processor and a memory, wherein the processor, by calling and executing a program or data stored in the memory, is used to acquire a currently used The beamformed information is simulated, and a shaped codebook of the digital beam is generated based on the information of the analog beamforming.

Embodiments of the present disclosure also provide a computer readable storage medium having stored thereon instructions for implementing the steps of any of the above methods.

The above aspects of the present disclosure include at least the following beneficial effects:

The above solution of the present disclosure obtains the information of the currently used analog beamforming; and generates a shaped codebook of the digital beam according to the information of the analog beamforming. The codebook of the digital beam within the analog beam can be dynamically generated to increase the digital beamforming gain.

DRAWINGS

Figure 1 is a schematic diagram of analog beamforming;

2 is a schematic diagram of the limitation of the range of digital beamforming in an analog beam;

Figure 3 is a schematic diagram showing the limitation of the range of digital beamforming in an analog beam;

4 is a communication flow chart of a terminal initial access to a data communication phase;

5 is a flowchart of a method for generating a digital beamforming codebook of the present disclosure;

6 is a diagram showing an execution process of a digital beamforming codebook generating apparatus of the present disclosure;

7 is a block diagram of a module of a digital beamforming codebook generating apparatus of the present disclosure.

detailed description

Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While the embodiments of the present invention have been shown in the drawings, the embodiments Rather, these embodiments are provided so that this disclosure will be more fully understood and the scope of the disclosure will be fully disclosed.

As shown in FIG. 4, in the 5G communication, the overall process of the terminal initially accessing to the data communication phase includes: Step 1, analog beam acquisition; Step 2, semi-dynamic SRS (probe reference signal) configuration and SRS transmission; Step 3 , CSI-RS transmission and CSI feedback; step 4, data transmission.

In the foregoing step 2, after determining the analog beam currently used by the terminal or the base station, in the system of the analog beam and the digital beam hybrid beamforming, the base station and/or the terminal are based on the information of the currently used analog beam. Dynamic generation of the digital beamforming codebook corresponding to the current channel can make the digital codebook reasonably represent the phase space in the analog beam, not to waste part of the digital code, and select the optimal codeword for digital beamforming.

As shown in FIG. 5, a first embodiment of the present disclosure provides a digital beamforming codebook generating method, including:

Step 51: Obtain information about the currently used analog beamforming;

Step 52: Generate a shaped codebook of the digital beam according to the information of the analog beamforming.

The embodiment of the present disclosure dynamically generates a digital beamforming codebook corresponding to the current channel based on the information of the currently used analog beam, so that the digital codebook can reasonably represent the phase space in the analog beam without wasting part of the digital code, and The optimal codeword is selected for digital beamforming.

A second embodiment of the present disclosure provides a digital beamforming codebook generating method, including:

Step 51: Obtain information about the currently used analog beamforming;

Step 53: Select, from the shaped codebook of the digital beam, a digital beamforming codeword that matches the current channel;

Among them, according to the formula:

A beamforming vector representing a codebook.

According to the embodiment of the present disclosure, the digital beamforming codebook corresponding to the current channel is dynamically generated based on the information of the currently used analog beam, so that the digital codebook can reasonably represent the phase space in the analog beam, and the optimal codeword is selected therefrom. Digital beamforming.

A third embodiment of the present disclosure provides a digital beamforming codebook generating method, including:

Step 51: Obtain information about the currently used analog beamforming;

Step 54: Feed the selected digital beamforming codeword matched by the current channel to the base station.

In this embodiment, both the terminal and the base station side can adopt the same algorithm. In the formed codebook of the digital beam, a digital beamforming codeword matching the current channel is selected; wherein, after the terminal is selected, the selected device can be further selected. The digital beamforming codeword of the current channel matching is fed back to the base station. That is to say, the above steps 51-53 can be performed either on the base station side or on the terminal side.

In the above embodiment of the present disclosure, step 51 may include:

Step 511: Acquire information about the analog beamforming currently used for the configuration of the sounding reference signal SRS.

In the above embodiment of the present disclosure, step 52 may include:

Step 521: Calculate the information of the analog beamforming information to obtain a rank number;

Step 522: Generate a shaped codebook of the digital beam according to the rank number.

Specifically, step 522 can include:

Step 5221, determining a phase space dimension of the beam according to the rank number;

Step 5222: Obtain a signal strength of the phase space dimension.

Step 5223: Generate a shaped codebook of the digital beam according to the signal strength of the phase space dimension. Specifically, the phase space dimension of the phase space dimension is greater than the first preset value, and the allocation is more than the second preset. The codeword of the value, generating a shaped codebook of the digital beam.

The digital codebook generating device based on the simulated beamforming information shown in FIG. 6 generates a digital beamforming codebook corresponding to the current analog beam according to the current analog beamforming information, such as the simulated beamwidth and the simulated beam direction. From the codebook, a corresponding digital beamforming codeword is selected.

Generating a digital codebook is to allocate the channel space. In the absence of an analog beam, the channel is generally full-rank, and the number of digital ports is equal to the dimension of the phase space; however, after the presence of the analog beam, the channel is largely down-ranked.

The specific processes of the above steps 521 and 522 are as follows:

Step 521, rank (analog beam information (width, direction), number of digital ports), and rank;

Step 522: Generate a digital codebook by using the LTE DFT codebook generation method according to the rank number. Since LTE has only two ranks of 2, 4, 8, and 16, the first step calculates that the rank is equal to 7, indicating that the phase space dimension is 7, A codebook of LTE port = 8 (indicating various directions in an 8-dimensional space) can be used.

Further, in the process of ranking, the svd algorithm can be used to know the strength of each phase space dimension (svd(H)=U*D*V), if a certain direction is strong (the direction in the D array is large), At this point, the codebook allocates more codewords in this direction, and the system beamforming is finer in this direction, and the overall performance is better.

In the method according to the foregoing embodiment of the present disclosure, after the hybrid beamforming, the user (or the base station) dynamically generates the digital beamforming codebook corresponding to the current channel according to the current analog beam information after selecting an analog beam. The digital codebook reasonably characterizes the phase space in the analog beam (not to waste part of the digital code), and selects the optimal codeword for digital beamforming.

Moreover, the digital beamforming gain of the present disclosure is greatly improved compared to the digital beamforming scheme under the conventional fixed codebook;

Moreover, the present disclosure can suppress analog inter-beam interference, and the number of terminals that can be simultaneously accessed is greatly improved compared with the conventional digital beamforming scheme under the fixed codebook.

Further, the method of the foregoing embodiment of the present disclosure is applied to a traditional wide beam scene such as a low frequency band, and the generated instant digital beamforming codebook can be regarded as a fixed version, thereby being compatible with the traditional 4G system.

As shown in FIG. 7, an embodiment of the present disclosure further provides a digital beamforming codebook generating apparatus 700, including:

The obtaining module 701 is configured to obtain information about the currently used analog beamforming;

The generating module 702 is configured to generate a shaped codebook of the digital beam according to the information of the analog beamforming.

The digital beamforming codebook generating device further includes:

The acquiring module 701 is specifically configured to: acquire information about the simulated beamforming currently used by the sounding reference signal SRS configuration.

The generating module 702 is specifically configured to: rank the information of the simulated beamforming to obtain a rank number; and generate a shaped codebook of the digital beam according to the rank number.

The selection module is specifically configured to:

According to the formula:

From the shaped codebook V of the digital beam, select the direction

The codeword v closest to the ideal beamforming vector w;

A beamforming vector representing a codebook.

The device of the present disclosure may be a device as shown in FIG. 7, or may be a device in a terminal or a base station or a terminal device or a base station device. The device is a device corresponding to all the methods in the foregoing method embodiments, and all implementations in the foregoing method embodiments are applicable to the device embodiment.

The device of the present disclosure also performs hybrid beamforming, and the user (or base station) dynamically generates a digital beamforming codebook corresponding to the current channel according to the current analog beam information after selecting an analog beam, and the digital codebook is properly characterized. Simulate the phase space within the beam (not to waste part of the digital code) and select the optimal codeword for digital beamforming.

Further, the device is applied to a traditional wide beam scene such as a low frequency band, and the generated instant digital beamforming codebook can be regarded as a fixed version, thereby being compatible with the traditional 4G system.

It will be appreciated that the above method embodiments may be implemented in hardware, software, firmware, middleware, microcode, or a combination thereof. For hardware implementation, the processing unit can be implemented in one or more Application Specific Integrated Circuits (ASICs), Digital Signal Processing (DSP), Digital Signal Processing Equipment (DSP Device, DSPD), programmable Programmable Logic Device (PLD), Field-Programmable Gate Array (FPGA), general purpose processor, controller, microcontroller, microprocessor, other electronic unit for performing the functions of the present application Or a combination thereof. For software implementations, the techniques herein can be implemented by modules (eg, procedures, functions, etc.) that perform the functions herein. The software code can be stored in memory and executed by the processor. The memory can be implemented in the processor or external to the processor. The memory can be either volatile memory or non-volatile memory, or can include both volatile and nonvolatile memory.

The above is a preferred embodiment of the present disclosure, and it should be noted that those skilled in the art can also make several improvements and refinements without departing from the principles of the present disclosure. It should be considered as the scope of protection of this disclosure.

Claims

A digital beamforming codebook generating method includes:

Obtaining information about the currently used analog beamforming;

A shaped codebook of the digital beam is generated based on the information of the analog beamforming.
The method of generating a digital beamforming codebook according to claim 1, further comprising:

From the shaped codebook of the digital beam, a digital beamforming codeword that matches the current channel is selected.
The method of generating a digital beamforming codebook according to claim 2, further comprising:

The selected current channel matched digital beamforming codeword is fed back to the base station.
The digital beamforming codebook generating method according to any one of claims 1 to 3, wherein the step of acquiring the currently used analog beamforming information comprises:

Obtain the information of the analog beamforming currently used for the sounding reference signal SRS configuration.
The digital beamforming codebook generating method according to claim 1 or 4, wherein the information of the analog beamforming comprises: width information of the analog beam, rotation direction information of the analog beam, and number of digital ports.
The digital beamforming codebook generating method according to any one of claims 1 to 5, wherein the step of generating a shaped codebook of the digital beam according to the information of the analog beamforming comprises:

Ranking the information of the analog beamforming to obtain a rank number;

A shaped codebook of the digital beam is generated according to the rank number.
The digital beamforming codebook generating method according to claim 6, wherein the step of generating a shaped codebook of the digital beam according to the rank number comprises:

Determining a phase space dimension of the beam according to the rank number;

Obtaining a signal strength of the phase space dimension;

A shaped codebook of the digital beam is generated according to a signal strength of the phase space dimension.
The digital beamforming codebook generating method according to claim 7, wherein the step of generating a shaped codebook of the digital beam according to a signal strength of the phase space dimension comprises:

For a phase space dimension in which the signal strength of the phase space dimension is greater than the first preset value, a codeword that is more than the second preset value is allocated, and a shaped codebook of the digital beam is generated.
The digital beamforming codebook generating method according to claim 2, wherein the step of selecting a digital beamforming codeword matching the current channel from the shaped codebook of the digital beam comprises:

According to the formula:
Selecting, from the shaped codebook V of the digital beam, a codeword v whose direction is closest to the ideal beamforming vector w; wherein
A beamforming vector representing a codebook.
A digital beamforming codebook generating device comprising:

An acquisition module, configured to obtain information about the currently used analog beamforming;

And a generating module, configured to generate a shaped codebook of the digital beam according to the information of the analog beamforming.
The digital beamforming codebook generating apparatus according to claim 10, further comprising:

And a selection module, configured to select, from the shaped codebook of the digital beam, a digital beamforming codeword that matches the current channel.
The digital beamforming codebook generating apparatus according to claim 11, further comprising:

And a feedback module, configured to feed back the selected digital beamforming codeword of the current channel to the base station.
The digital beamforming codebook generating apparatus according to any one of claims 10 to 12, wherein the acquiring module is specifically configured to: acquire information of analog beamforming currently used for performing the sounding reference signal SRS configuration.
The digital beamforming codebook generating apparatus according to claim 10 or 13, wherein the information of the analog beamforming comprises: width information of the analog beam, rotation direction information of the analog beam, and number of digital ports.
The digital beamforming codebook generating apparatus according to any one of claims 10 to 14, wherein the generating module is specifically configured to: rank the information of the analog beamforming to obtain a rank number; Generating a shaped codebook of the digital beam.
The digital beamforming codebook generating apparatus according to claim 15, wherein the generating module is specifically configured to: determine a phase space dimension of the beam according to the rank number after obtaining the rank number; and acquire the phase space dimension Signal strength; a shaped codebook of the digital beam is generated according to a signal strength of the phase space dimension.
The digital beamforming codebook generating apparatus according to claim 16, wherein the generating module is configured to: when generating a shaped codebook of the digital beam according to a signal strength of the phase space dimension, specifically:

For a phase space dimension in which the signal strength of the phase space dimension is greater than the first preset value, a codeword that is more than the second preset value is allocated, and a shaped codebook of the digital beam is generated.
The digital beamforming codebook generating apparatus according to claim 11, wherein the selecting module is specifically configured to:

According to the formula:
Selecting, from the shaped codebook V of the digital beam, a codeword v whose direction is closest to the ideal beamforming vector w; wherein
A beamforming vector representing a codebook.
A digital beamforming codebook generating device includes a processor and a memory, wherein

The processor, by calling and executing the program or data stored in the memory, is configured to acquire information of the currently used analog beamforming, and generate a shaped codebook of the digital beam according to the information of the analog beamforming.
A computer readable storage medium having stored thereon instructions for implementing the steps of the method of any of claims 1-9.