JP7244160B2 - Information transmission method, channel estimation method, base station, user equipment, system and program - Google Patents

Description

The present invention relates to the field of mobile communication, in particular to a channel estimation method, a base station, a User Equipment (UE) and a system.

As technology develops, users are increasingly demanding to perform communications in high-speed scenarios. For example, a user performs communication on a moving high-speed train. When the UE performs communication in fast moving state, multiple problems arise, such as low throughput rate, frequent handovers, high handover failure rate, and high radio link failure rate.

In the prior art, the solution to problems such as frequent handovers and low throughput in high-speed rail mobile communication is to use zonal topology. That is, a plurality of Radio Remote Units (RRUs) are attached to a Base Band Unit (BBU), and the RRUs are arranged along the tracks. For ease of explanation, communication scenarios in such topologies are referred to as wireless remote scenarios. In the radio remote scenario, multiple RRUs belong to the same physical cell, share the same cell identity (ID), serve UEs in the cell simultaneously, and transmit the same radio signal. From the perspective of the UE side, the cell radius is greatly expanded, the number of UE handovers in the fast moving process is effectively reduced, the network handover signaling overhead is reduced, and the handover failure rate is reduced. In addition, since multiple RRUs simultaneously transmit downlink signals to the UE, the Signal to Interference plus Noise Ratio (SINR) of the signal received at the UE side is also greatly improved.

Wireless remote deployment can effectively reduce the number of handovers and improve the SINR of the signal received by the UE. However, in the above wireless remote scenario, multiple RRUs simultaneously transmit downlink signals for the UE, so the signals received by the UE are relatively complex, and the channel estimation results are very unsatisfactory; Affects the downlink data throughput of the UE.

Embodiments of the present invention provide a channel estimation method, apparatus and system to effectively improve the accuracy of channel estimation, thereby effectively improving the downlink data throughput of a UE.

According to a first aspect, a method of transmitting information is provided. The method comprises establishing a connection to the UE by the base station, and sending notification information to the UE indicating that the UE is in a wireless remote scenario, wherein the notification information is applicable to the wireless remote scenario. The channel estimation algorithm is used to instruct the UE to perform channel estimation by using a simple channel estimation algorithm, which performs channel estimation on signals obtained after downlink signals from multiple RRUs are superimposed. and a step used to perform the estimation.

Relating to the first aspect, in a first possible implementation of the first aspect, performing channel estimation on a signal obtained after the downlink signals from multiple RRUs are superimposed includes multiple determining the delay and Doppler shift of the downlink signal from each of the RRUs of the RRU; performing delay and frequency compensation on the downlink signal of each RRU according to the delay and Doppler shift; determining Wiener coefficients of the signal and performing channel estimation by using the Wiener coefficients.

In relation to the first aspect, or the first possible implementation of the first aspect, in a second possible implementation of the first aspect, sending notification information to the UE indicating that the UE is in a wireless remote scenario. transmitting Radio Resource Control (RRC) dedicated signaling to the UE, wherein a first indicator bit in the RRC dedicated signaling is used to indicate that the UE is in a radio remote scenario; or sending a system message to the UE, wherein a second indicator bit in the system message is used to indicate that the UE is in a wireless remote scenario, or the system Sending a message to the UE, the system message carrying cell identities of wireless remote coverage cells.

In relation to the first aspect, or the first or second possible implementations of the first aspect, in the third possible implementation of the first aspect, the notification information indicating that the UE is in a wireless remote scenario Prior to transmitting to the UE, the method further comprises determining that the UE is in fast moving state.

According to a second aspect, a channel estimation method is provided. The method includes receiving notification information by the UE, the notification information indicating that the UE is in a wireless remote scenario, and determining a channel estimation algorithm applicable to the wireless remote scenario according to the notification information. performing channel estimation by using a channel estimation algorithm used to perform channel estimation on the signal obtained after the downlink signals from multiple RRUs are superimposed Steps.

Concerning the second aspect, in a first possible implementation of the second aspect, performing channel estimation on a signal obtained after the downlink signals from multiple RRUs are superimposed includes multiple determining the delay and Doppler shift of the downlink signal from each of the RRUs of the RRU; performing delay and frequency compensation on the downlink signal of each RRU according to the delay and Doppler shift; determining the Wiener coefficients of and performing channel estimation by using the Wiener coefficients.

Relating to the second aspect, or the first possible implementation of the second aspect, in the second possible implementation of the second aspect, the UE receiving notification information, the notification information comprising: Indicating that the UE is in a wireless remote scenario, the step of receiving RRC dedicated signaling by the UE, wherein a first indicator bit in the RRC dedicated signaling is used to indicate that the UE is in a wireless remote scenario. used or receiving a system message by the UE, wherein the second indicator bit in the system message is used to indicate that the UE is in a wireless remote scenario; or Receiving a system message by the UE, the system message carrying cell identities of wireless remote coverage cells.

According to a third aspect, a base station is provided. The base station comprises a processing unit configured to control a transmission unit to establish a connection to the UE, and a transmission further configured to transmit notification information to the UE indicating that the UE is in a wireless remote scenario. unit, the notification information is used to instruct the UE to perform channel estimation by using a channel estimation algorithm applicable to the wireless remote scenario, the channel estimation algorithm is a downlink from multiple RRUs; a transmission unit used to perform channel estimation on the signal obtained after the link signal is superimposed.

Relating to the third aspect, in a first possible implementation of the third aspect, perform channel estimation on a signal obtained after the downlink signals from multiple RRUs are superimposed, indicated by the transmitting unit. Performing is determining delays and Doppler shifts of downlink signals from each of a plurality of RRUs, and performing delay and frequency compensation on the downlink signals of each RRU according to the delays and Doppler shifts. and determining the Wiener coefficients of the compensated signal and performing channel estimation by using the Wiener coefficients.

In relation to the third aspect, or the first possible implementation of the third aspect, in the second possible implementation of the third aspect, the transmitting unit specifically performs RRC dedicated signaling, The first indicator bit in the signaling is used to indicate that the UE is in a wireless remote scenario, sends RRC dedicated signaling to the UE, or is a system message and the second indicator bit in the system message is configured to send a system message to the UE that is used to indicate that the UE is in a wireless remote scenario, or send a system message carrying the cell identity of the wireless remote coverage cell to the UE. .

In relation to the third aspect, or the first or second possible implementations of the third aspect, in the third possible implementation of the third aspect, the processing unit further determines that the UE is in a wireless remote scenario. is configured to determine that the UE is in a fast moving state before the sending unit sends to the UE notification information indicating the .

According to a fourth aspect, a UE is provided. The UE is a receiving unit configured to receive notification information, the notification information indicating that the UE is in a wireless remote scenario, and a wireless remote control according to the notification information received by the receiving unit. A processing unit configured to perform channel estimation by using a channel estimation algorithm applicable to a scenario, wherein the channel estimation algorithm is a signal obtained after downlink signals from multiple RRUs are superimposed. and a processing unit used to perform channel estimation for .

Relating to the fourth aspect, in a first possible implementation of the fourth aspect, the processing unit specifically determines delays and Doppler shifts of downlink signals from each of the plurality of RRUs; and performing delay and frequency compensation on each RRU downlink signal according to the Doppler shift; determining the Wiener coefficients of the compensated signals; and performing channel estimation by using the Wiener coefficients. configured to do

Relating to the fourth aspect, or the first possible implementation of the fourth aspect, in the second possible implementation of the fourth aspect, the receiving unit specifically uses RRC dedicated signaling to A first indicator bit in the signaling is used to indicate that the UE is in a wireless remote scenario, receives RRC dedicated signaling or a system message, and a second indicator bit in the system message is The UE is configured to receive a system message used to indicate that it is in a wireless remote scenario or to receive a system message carrying cell identities of wireless remote coverage cells.

According to a fifth aspect, a base station is provided. The base station comprises a communication interface, a memory, and a processor, the memory configured to store program instructions, the processor configured to cause the base station to communicate with the UE by using the communication interface according to the program instructions stored in the memory. and transmitting, by using the communication interface, notification information to the UE indicating that the UE is in a wireless remote scenario, the notification information being in the wireless remote scenario is used to instruct the UE to perform channel estimation by using a channel estimation algorithm applicable to and the operations used to perform channel estimation for the channel.

Relating to the fifth aspect, in a first possible implementation of the fifth aspect, instructing the UE to perform channel estimation on the signal obtained after the downlink signals from multiple RRUs are superimposed. the processor performing operations to determine delays and Doppler shifts of downlink signals from each of a plurality of RRUs; performing compensation; determining Wiener coefficients of the compensated signal; and performing channel estimation by using the Wiener coefficients.

In relation to the fifth aspect, or the first possible implementation of the fifth aspect, in the second possible implementation of the fifth aspect, the UE sends notification information indicating that it is in a wireless remote scenario to the communication interface. The processor performs an operation to send to the UE by using a communication interface, by using RRC dedicated signaling, wherein the first indicator bit in the RRC dedicated signaling indicates that the UE is in a wireless remote scenario By sending RRC dedicated signaling to the UE or using a communication interface, the second indicator bit in the system message indicates that the UE is in a wireless remote scenario. or by using a communication interface to send a system message carrying cell identities of wireless remote coverage cells to the UE. include.

In relation to the fifth aspect, or the first or second possible implementations of the fifth aspect, in the third possible implementation of the fifth aspect, the processor further comprises: , the operation of determining that the UE is in a fast moving state prior to the operation of sending notification information to the UE by using the communication interface indicating that the UE is in a wireless remote scenario.

According to a sixth aspect, a UE is provided. The UE comprises a communication interface, a memory and a processor, the memory configured to store program instructions, the processor receiving notification information by using the communication interface according to the program instructions stored in the memory. An operation, wherein the signaling information indicates that the UE is in a wireless remote scenario; and an operation of performing channel estimation by using a channel estimation algorithm applicable to the wireless remote scenario according to the signaling information. A channel estimation algorithm is configured to perform operations used to perform channel estimation on a signal obtained after downlink signals from multiple RRUs are superimposed.

Relating to the sixth aspect, in a first possible implementation of the sixth aspect, the processor performs an operation of performing channel estimation on a signal obtained after downlink signals from multiple RRUs are superimposed. Performing is determining delays and Doppler shifts of downlink signals from each of a plurality of RRUs, and performing delay and frequency compensation on the downlink signals of each RRU according to the delays and Doppler shifts. and determining the Wiener coefficients of the compensated signal and performing channel estimation by using the Wiener coefficients.

Relating to the sixth aspect, or the first possible implementation of the sixth aspect, in the second possible implementation of the sixth aspect, an operation of receiving notification information by using a communication interface: , the notification information indicates that the UE is in a wireless remote scenario, the processor performing the operation is by using a communication interface, RRC dedicated signaling, wherein the first indicator bit in the RRC dedicated signaling is: By receiving RRC dedicated signaling or using a communication interface used to indicate that the UE is in a radio remote scenario, a system message, wherein a second indicator bit in the system message is Receiving a system message used to indicate that the UE is in a wireless remote scenario or carrying cell identities of wireless remote coverage cells by using the communication interface. including.

According to a seventh aspect, a communication system is provided. The system is a base station configured to establish a connection to the UE and send notification information to the UE indicating that the UE is in a wireless remote scenario, wherein the notification information is applicable to the wireless remote scenario. It is used to instruct the UE to perform channel estimation by using a channel estimation algorithm, which performs channel estimation on a signal obtained after downlink signals from multiple RRUs are superimposed. receiving signaling information from the base station indicating that the UE is in a wireless remote scenario; and according to the signaling information, a channel estimation algorithm applicable to the wireless remote scenario. and performing channel estimation by using a channel estimation algorithm used to perform channel estimation on a signal obtained after downlink signals from multiple RRUs are superimposed. a UE configured to:

Relating to the seventh aspect, in a first possible implementation of the seventh aspect, the UE specifically determines delays and Doppler shifts of downlink signals from each of a plurality of RRUs; performing delay and frequency compensation on the downlink signal of each RRU according to the Doppler shift; determining Wiener coefficients of the compensated signals; and performing channel estimation by using the Wiener coefficients. configured to do so.

With respect to the seventh aspect, or the first possible implementation of the seventh aspect, in the second possible implementation of the seventh aspect, the base station specifically performs RRC dedicated signaling, The first indicator bit in the signaling is used to indicate that the UE is in a wireless remote scenario, sends RRC dedicated signaling to the UE, or is a system message and the second indicator bit in the system message is configured to send a system message to the UE that is used to indicate that the UE is in a wireless remote scenario, or send a system message carrying the cell identity of the wireless remote coverage cell to the UE. .

In relation to the seventh aspect, or the first or second possible implementations of the seventh aspect, in the third possible implementation of the seventh aspect, the base station further determines that the UE is in a wireless remote scenario. is configured to determine that the UE is in a fast moving state before sending notification information indicating to the UE.

In an embodiment of the present invention, the base station sends notification information to the UE indicating that the UE is in a wireless remote scenario, so that the UE can change the adopted channel estimation algorithm after receiving the notification information. can be done. During channel estimation, for the feature that the UE receives downlink signals transmitted to the UE by multiple RRUs in a radio remote scenario, for the signals obtained after multiple downlink signals are superimposed, the channel A suitable channel estimation algorithm is used to perform the estimation, effectively improving the accuracy of the channel estimation and thereby the downlink data throughput of the UE.

1 is a schematic diagram of a network architecture according to an embodiment of the invention; FIG.

1 is a schematic diagram of an application scenario according to an embodiment of the present invention; FIG.

4 is a signal flow diagram according to Embodiment 1 of the present invention; FIG.

FIG. 4 is a signal flow diagram according to Embodiment 2 of the present invention;

FIG. 5 is a signal flow diagram according to Embodiment 3 of the present invention;

FIG. 4 is a structural diagram of a base station according to Embodiment 4 of the present invention;

FIG. 5 is a structural diagram of a UE according to Embodiment 5 of the present invention;

Fig. 6 is a structural diagram of a base station according to Embodiment 6 of the present invention;

FIG. 8 is a structural diagram of a UE according to Embodiment 7 of the present invention;

FIG. 8 is a structural diagram of a communication system according to Embodiment 8 of the present invention;

In order to make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are presented below in conjunction with the accompanying drawings in the embodiments of the present invention. explain. Apparently, the described embodiments are a part rather than all of the embodiments of the present invention. All other embodiments obtained by persons of ordinary skill in the art based on the embodiments of the present invention without creative efforts should fall within the protection scope of the present invention.

FIG. 1 is a schematic diagram of a network architecture according to one embodiment of the present invention. The present embodiments of the present invention may be applied to 3rd-Generation (3G) mobile communication technology networks or may be applied to Long Term Evolution (LTE) networks. For ease of explanation, an LTE network is used below as an illustrative example. Referring to FIG. 1, in an Evolved-Universal Terrestrial Radio Access Network (E-UTRAN) communication system 100 of an LTE network, the E-UTRAN communication system 100 includes a number of base stations 110 and others. network entities to support several UEs 120 to carry out communications. Some of the UEs 120 are located on High Speed Trains (HSTs) traveling at high speed. These UEs 120 may demodulate the downlink data received from the base station 110 using methods provided in embodiments of the present invention.

The base station 110 may be an LTE Evolved NodeB (eNB). One base station 110 may support/manage one or more cells. When UE 120 needs to communicate with the network, it selects one cell and initiates access.

UE 120 may alternatively be referred to as a Mobile Terminal (MT) or a Mobile Station (MS), etc., and is connected to one or more cores by using a Radio Access Network (RAN). Communication with a network may be performed.

A core network device 130 is connected to one or more base stations 110 and has a Mobility Management Entity (MME).

This embodiment of the invention may be applied to various communication systems. According to different communication systems, the specific base station devices are different, specifically Base Station Controller (BSC), Radio Network Controller (RNC), Evolved Node B (eNB). ), or a NodeB.

This embodiment of the invention may be applied to high-speed scenarios where multiple nodes perform joint transmission, high-speed rail mobile communication in a wireless remote scenario is used below as an illustrative example only.

FIG. 2 is a schematic diagram of an application scenario according to an embodiment of the present invention. The scenario is a wireless remote scenario, where a zonal topology is used. Multiple RRUs are attached to the BBU, and the RRUs are arranged along the line. A plurality of RRUs is at least two RRUs, and the number of RRUs may be set as needed. The number of RRUs shown in this figure is three . The numbers are illustrative examples only and are not intended to limit this embodiment of the invention. BBU in the wireless remote scenario corresponds to the baseband unit of the base station, and RRU corresponds to the radio frequency unit of the base station. In the radio remote scenario, multiple RRUs belong to the same physical cell, share the same cell ID, serve UEs in the cell simultaneously, and transmit the same radio signal. From the perspective of the UE side, the cell radius is greatly expanded, the number of UE handovers in the fast moving process is effectively reduced, the network handover signaling overhead is reduced, and the handover failure rate is reduced. In addition, since multiple RRUs simultaneously transmit downlink signals for the UE, the SINR of the received signal at the UE side is also greatly improved.

Wireless remote deployment can effectively reduce handovers and improve the SINR of signals received by the UE. However, the results obtained by conventional channel estimation algorithms are relatively unsatisfactory in wireless remote scenarios, resulting in poor downlink signal demodulation performance and low throughput rates.

Usually the UE has automatic time-frequency tracking capability. In the low speed scenario of conventional macro networks, the UE can maintain the desired tracking performance for the received signal and perform channel estimation accurately. However, in the wireless remote scenario of high-speed rail dedicated networks, the signals received by the UE are relatively complex. Assuming the UE is served by two RRUs at the same time, there are two main paths in the signal received by the UE. The power, relative delay, and Doppler shift of the two main paths vary over time, with the signs of the Doppler shifts being opposite. In this case, the results of conventional channel estimation are inaccurate and affect the downlink throughput of the terminal.

In the radio remote scenario of high-speed rail dedicated network, the signal received by the UE is obtained by superimposing the downlink signals from multiple RRUs, and the downlink arriving signals from the RRUs have different powers, relative delays, and It has a Doppler shift. For the characteristics of the downlink signal received by the UE in this scenario, in this embodiment of the invention, a channel estimation algorithm specifically applicable to this scenario is used for channel estimation to obtain the channel Improve the accuracy of the estimation, thereby improving the throughput of the UE.

FIG. 3 is a signal flow diagram according to Embodiment 1 of the present invention. The base station may send signaling information to the UE indicating that the UE is in a wireless remote scenario, and the UE may change its channel estimation algorithm after receiving the signaling information. Referring to FIG. 3, the method comprises the following steps.

Step 301: A base station establishes a connection to a UE.

A base station is a base station using wireless remote deployment. After the UE establishes a connection to the base station, the UE is in a wireless remote scenario. The process by which the base station establishes a connection to the UE includes, but is not limited to, a case in which a UE in idle state establishes a connection to the base station by cell selection and cell reselection, a UE in connected state is handed over. and the case where the UE establishes a connection to the base station by Radio Resource Control (RRC) reestablishment.

Step 302: The base station sends notification information to the UE indicating that the UE is in a wireless remote scenario.

The signaling information is used to instruct the UE to perform channel estimation by using channel estimation algorithms applicable to wireless remote scenarios. A channel estimation algorithm is used to perform channel estimation on the signal obtained after the downlink signals from multiple RRUs are superimposed.

In this embodiment of the present invention, the base station may add notification information to the RRC dedicated signaling and send the RRC dedicated signaling to the UE, or add notification information to the system message and send the system message to the UE. can be sent to

When the UE is in fast moving state, the channel estimation is likely to be inaccurate, so the base station may first determine whether the UE is in fast moving state. When determining that the UE is in fast moving state, the base station sends notification information to the UE indicating that the UE is in a wireless remote scenario; otherwise, the base station does not send notification information. When the moving speed of the UE exceeds a preset speed threshold, the UE may be considered to be in fast moving state. For example, the speed threshold may be set at 200 km/h. Determining whether the UE is in fast moving state is an optional step.

Step 303: The UE receives notification information. Here, the notification information indicates that the UE is in a wireless remote scenario.

Specifically, the UE receives RCC dedicated signaling and the first indicator bit in the RRC dedicated signaling is used to indicate that the UE is in a radio remote scenario. Alternatively, the UE receives a system message and a second indicator bit in the system message is used to indicate that the UE is in a wireless remote scenario.

Step 304: The UE performs channel estimation by using channel estimation algorithms applicable to wireless remote scenarios according to the signaling information.

A channel estimation algorithm is used to perform channel estimation on the signal obtained after the downlink signals from multiple RRUs are superimposed. Specifically, the delay and Doppler shift of the downlink signal from each RRU are determined, Wiener coefficients are determined according to the delay and Doppler shift, and channel estimation is performed by using the Wiener coefficients.

In this embodiment of the present invention, the base station sends notification information to the UE indicating that the UE is in a wireless remote scenario, so that the UE can change the adopted channel estimation algorithm after receiving the notification information. . During channel estimation, for the feature that the UE receives downlink signals transmitted to the UE by multiple RRUs in a radio remote scenario, for the signals obtained after multiple downlink signals are superimposed, the channel The estimation is performed to effectively improve the accuracy of channel estimation, thereby effectively improving the downlink data throughput of the UE.

FIG. 4 is a signal flow diagram according to Embodiment 2 of the present invention. The base station sends notification information to the UE indicating that the UE is in a radio remote scenario by using RRC dedicated signaling. Referring to FIG. 4, the method comprises the following steps.

Step 401: A base station establishes a connection to a UE.

Step 402: The UE sends indication information to the base station. Here, indication information is used to indicate that the UE supports channel estimation algorithms applicable to wireless remote scenarios.

Step 403: The base station determines whether the UE is in fast moving state.

When the determination result is that the UE is in fast moving state, step 404 is performed, otherwise no processing is performed.

The base station may first obtain the moving speed of the UE, and then determine whether the moving speed of the UE is greater than the speed threshold according to a preset speed threshold, and determine whether the moving speed of the UE is greater than the speed threshold. When it is greater than the threshold, the UE decides to be in fast moving state.

In this embodiment of the invention, alternatively, the base station may determine whether the UE is in fast moving state by using any one of the following schemes.

First method: UE reports mobility status to the base station. For example, when accessing a base station, a UE that supports mobility status reporting adds a message element (Information Element, IE) of the UE's mobility status to signaling sent to the base station, and the base station sends the signaling and the signaling may specifically be an RRC connection establishment complete message.

Second method: the base station obtains the number of handovers of the UE in a preset period, and assigns a speed range to the UE according to the number of handovers per unit time of the UE. For example, when the UE performs 5 or more handovers per minute, the speed range is defined as fast.

Third scheme: The base station determines the velocity range of the UE according to the Doppler shift of the received uplink signal of the UE. For example, a Doppler shift of 1000 Hz or greater indicates high speed.

Fourth mode: the base station may acquire the location information of the UE through positioning on the network side, and the velocity information of the UE according to the change of the UE's location, thereby allocating a velocity range to the UE. For example, the speed range is high when the UE speed reaches 200 km/h or higher.

Fifth method: the base station obtains the speed data information of the UE from the application layer with speed information.

Step 403 is an optional step. In this embodiment of the invention, step 403 may not be included, and step 404 is directly performed after step 402 is performed.

Step 404: The base station sends RRC dedicated signaling to the UE. Here, the first indicator bit in RRC dedicated signaling is used to indicate that the UE is in a radio remote scenario.

Specifically, whether the UE is in a wireless remote scenario or not may be indicated by using a boolean variable. For example, 0 represents that the UE is not in a wireless remote scenario and 1 represents that the UE is in a wireless remote scenario.

Step 405: The UE performs channel estimation by using a channel estimation algorithm applicable to wireless remote scenarios according to the indication of RRC dedicated signaling.

A channel estimation algorithm performs time-frequency tracking on the downlink signal from each of a plurality of RRUs to determine the delay and Doppler shift of the downlink signal from each RRU, and the Wiener It is used to determine the (Wiener) coefficients and perform channel estimation by using the Wiener coefficients.

After entering the radio remote scenario, the UE receives an indication in the RRC dedicated signaling to enable the channel estimation algorithms applicable to the above scenarios to improve the accuracy of the UE's channel estimation in the above scenarios. , thereby improving the downlink throughput of the UE and improving network performance.

FIG. 5 is a signal flow diagram according to Embodiment 3 of the present invention. The base station sends notification information to the UE indicating that the UE is in a wireless remote scenario by using system messages. Referring to FIG. 5, the method comprises the following steps.

Step 501: A base station establishes a connection to a UE.

Step 502: The UE determines whether the UE is in fast moving state.

In this embodiment of the invention, the UE may determine whether the UE is in fast moving state by using schemes including but not limited to the following schemes.

The first method: test the speed by using the Global Positioning System (GPS) of the UE. A speed of 300 km/h or higher is considered high speed.

Second method: use the number of handovers that occur per unit time. If the number of handovers is 5 or more per minute, the speed is considered fast.

Third scheme: Use the number of cell reselections that occur per unit time. If the number of cell reselections is 5 or more per minute, the speed is considered fast.

Fourth method: Perform judgment according to the duration of past cells. A rate is considered fast if the average duration over several previous cells is less than 10 seconds.

Step 503: Upon determining that the UE is in the fast moving state, the UE sends indication information indicating that the UE is in the fast moving state to the base station.

In addition, indication information may also be sent indicating that the UE supports channel estimation algorithms applicable to wireless remote scenarios.

Step 504: The base station sends a system message to the UE. Here, a second indicator bit in the system message is used to indicate that the UE is in a wireless remote scenario.

Step 505: The UE performs channel estimation by using a channel estimation algorithm applicable to wireless remote scenarios according to the indication of the system message.

A channel estimation algorithm determines delays and Doppler shifts of downlink signals from each of a plurality of RRUs and performs delay and frequency compensation on the downlink signals of each RRU according to the delays and Doppler shifts. and determining the Wiener coefficients of the compensated signal and performing channel estimation by using the Wiener coefficients.

After accessing the wireless remote scenario, the UE activates the channel estimation algorithm applicable to the above scenarios by reading the indication in the system message to improve the accuracy of the UE's channel estimation in the above scenarios, and This improves the downlink throughput of the UE and improves network performance.

Additionally, in a wireless remote scenario, the base station may alternatively implicitly indicate that the UE is in a wireless remote scenario. For example, the system message may carry indication information indicating that the cell is a wireless remote coverage cell. If the UE determines that it belongs to a wireless remote coverage cell, the UE activates channel estimation algorithms applicable to the wireless remote scenario.

A channel estimation algorithm applicable to a wireless remote scenario, used in this embodiment of the invention, is as follows by using an example where a UE is served simultaneously by two RRUs sharing the same cell ID: is succinctly explained.

The channel estimation algorithm has four main stages: delay estimation, Doppler estimation, delay and frequency compensation, and channel estimation. At each of these stages, an appropriate method needs to be selected for processing in a wireless remote scenario.

および

が取得され得る。 Stage 1: Perform delay estimation. An Inverse Fast Fourier Transform (IFFT) is performed on the signal to obtain the position of the first arriving path peak value of each main path, which gives the delay of the two main paths

and

can be obtained.

Step 2: Perform Doppler estimation. Doppler estimation is Doppler shift estimation. Doppler estimates used in conventional channel estimation algorithms are obtained based on calculations of signal phase excursions of neighboring pilot symbols. To obtain the Doppler shift, the signal phase difference of the pilot signal positions of neighboring Common Reference Signals (CRS) on the same subcarrier is divided by the time interval. However, in a wireless remote scenario, since there are downlink signals from multiple RRUs, the Doppler shift of each signal is different and the dominant signal changes over time as the power of each signal changes. As a result, the Doppler shift cannot be accurately estimated using conventional Doppler estimation methods. In this embodiment of the invention, a method for estimating the Doppler shift of multiple harmonics from noise is used, eg, a non-linear LS estimation method.

Signal shifts from multiple RRUs may be estimated by using methods such as the non-linear LS method or higher order Yule-Walker equations. An example in which a UE is simultaneously served by two RRUs is used herein and the Doppler shifts of the two paths are calculated by using the non-linear LS method.

である。 The time-domain cross-correlation function of the received signal is

is.

のように簡略化され得る。 The time domain cross-correlation function is

can be simplified as

：時間－周波数位置（ｘ，ｌ）と（ｋ，ｋ＋Δｋ）との間の相互相関関数、
Ｅ（）：期待値、

：時間－周波数位置（ｋ，ｘ）におけるＬＳチャネル推定、
ｎ：ノイズ、
ｐ＝０または１：０番目のＲＲＵ信号および１番目のＲＲＵ信号を表す、
Ｎ：使用されるサブキャリア数、

：ｐ番目のＲＲＵ信号のパワー、

：矩形波のＦＦＴ変換、すなわち、

：ｐ番目のＲＲＵ信号のドップラーシフト、
Ｆｄ，ｐ＝ｆｄ，ｐ／Δｆ、式中、Δｆはサブキャリア間隔、

：ｐ番目のＲＲＵ信号の遅延、および、

：時間単位。 The meaning of each parameter in the time domain cross-correlation function is as follows.

: the cross-correlation function between the time-frequency locations (x,l) and (k,k+Δk),
E(): expected value,

: LS channel estimation at time-frequency position (k, x),
n: noise;
p=0 or 1: represents the 0th RRU signal and the 1st RRU signal,
N: number of subcarriers used;

: the power of the p-th RRU signal,

: the FFT transform of the square wave, i.e.,

: Doppler shift of the p-th RRU signal,
Fd,p=fd,p/Δf, where Δf is the subcarrier spacing;

: the delay of the p-th RRU signal, and

:Time unit.

The expected value in the equation can be obtained by frequency domain averaging.

である。 When the difference between the powers of the two paths is large, for example when the difference is 5 dB or more,

is.

である。 When the difference between the powers of the two paths is small, for example when the difference is 5 dB or less,

is.

のように示される。 From the above, it can be seen that when two paths are close together, there are cross terms (the last two terms) in the equation that cannot be canceled. In the wireless remote scenario, the two routes are close only when the train is located halfway between the two RRUs. In this case, the Doppler shifts of the two paths change little over time, and the cross-term can be suppressed by time-domain averaging. This is

is shown as

のように表され得る。 Therefore, the average cross-correlation function is

can be expressed as

のように示される。 For simplicity, the formula is

is shown as

が取得され得る。 the following formula,

can be obtained.

Additionally, the Doppler shift of the two paths can be obtained by using the following equations.

である。 During the ceremony,

is.

where m represents the position of the OFDM symbol in each subframe, m1: #0 and #4, #7 and #11, m2: #0 and #7, #4 and #11, m3: #4 and #7, m4: #0 and #11.

Step 3: Perform delay and frequency compensation. Common methods may be used for delay compensation. For frequency compensation, in this embodiment of the invention, first the powers of the two paths need to be determined. If the difference in power of the two paths is large, for example 5 dB or more, frequency compensation is performed according to the stronger path. If the powers of the two paths are similar, the Doppler shift and delay estimation may be performed separately for the two paths. Wiener coefficients are calculated according to the estimated values. By adjusting the baseband center frequency of the UE's local oscillator to the center of the Doppler shift of the two paths, inter-carrier interference may be reduced.

Step 4: Perform channel estimation. In this embodiment of the invention, channel estimates at non-pilot positions may be obtained based on computation of channel estimates at pilot positions.

Specifically, the channel estimates at the non-pilot positions are obtained by multiplying the Wiener coefficient matrix with the channel estimates at the pilot positions.

式中、

は、非パイロット位置におけるチャネル推定を表し、

は、ウィーナー係数行列を表し、

は、パイロット位置におけるチャネル推定を表す。ここで、ウィーナー係数行列は、時間領域および周波数領域の相互相関関数に基づいて取得される。

During the ceremony,

represents the channel estimate at the non-pilot positions, and

is the Wiener coefficient matrix, and

represents the channel estimate at the pilot positions. Here, the Wiener coefficient matrix is obtained based on the cross-correlation function in time domain and frequency domain.

は、パイロットシンボルのチャネル推定であり、受信されたシーケンスをローカルシーケンスで除算することによって取得され得る。これは、従来の方法と同一である。ＷＭＭＳＥは、１次元線形フィルタリングを２回使用することによって取得され得る。すなわち、周波数に対してまずウィーナーフィルタリングが実行され、その後、時間領域に対してフィルタリングが実行される。周波数領域関連関数は次の通りである。

is the channel estimate of the pilot symbols and can be obtained by dividing the received sequence by the local sequence. This is the same as the conventional method. WMMSE can be obtained by using 1-dimensional linear filtering twice. That is, Wiener filtering is first performed on the frequency, and then filtering is performed on the time domain. The frequency domain related functions are as follows.

The time domain related functions are as follows.

のように表され得る。 Therefore, frequency filtering is

can be expressed as

のように表され得る。 Time domain filtering is

can be expressed as

Experiments show that the conventional channel estimation method is inaccurate and the UE throughput is low, and although the signal-to-noise ratio is greatly improved, there still exists a throughput bottleneck. However, in the channel estimation algorithm provided in this embodiment of the invention, the downlink throughput of the UE obtains a clear gain.

FIG. 6 is a structural diagram of a base station according to Embodiment 4 of the present invention. A base station is configured to perform the channel estimation method provided in the embodiments of the present invention. The base station has a processing unit 601 configured to control a transmitting unit 602 to establish a connection to the UE, and further configured to transmit notification information to the UE indicating that the UE is in a wireless remote scenario. a transmitting unit 602, wherein the signaling information is used to instruct the UE to perform channel estimation by using a channel estimation algorithm applicable to a wireless remote scenario, the channel estimation algorithm being applied to multiple RRUs; and a transmitting unit 602 used to perform channel estimation on the signal obtained after the downlink signal from is superimposed.

Optionally, performing channel estimation on the signal obtained after the downlink signals from multiple RRUs are superimposed, indicated by transmitting unit 602, is performed on the downlink signal from each of the multiple RRUs. determining a delay and Doppler shift; performing delay and frequency compensation on the downlink signal of each RRU according to the delay and Doppler shift; determining a Wiener coefficient of the compensated signal; and performing channel estimation by using.

Optionally, the transmitting unit 602 specifically transmits RRC dedicated signaling, wherein the first indicator bit in the RRC dedicated signaling is used to indicate that the UE is in a radio remote scenario. Send to the UE, or a system message, wherein a second indicator bit in the system message is configured to send a system message to the UE, which is used to indicate that the UE is in a wireless remote scenario .

Optionally, the processing unit 601 is further configured to determine that the UE is in fast moving state before the transmitting unit 602 sends to the UE notification information indicating that the UE is in a wireless remote scenario.

FIG. 7 is a structural diagram of a UE according to Embodiment 5 of the present invention. A UE is configured to perform the channel estimation method provided in the embodiments of the present invention. The UE is a receiving unit 701 configured to receive notification information, the notification information indicating that the UE is in a wireless remote scenario, and according to the notification information received by the receiving unit 701. , a processing unit 702 configured to perform channel estimation by using a channel estimation algorithm applicable to a wireless remote scenario, wherein the channel estimation algorithm is performed after the downlink signals from multiple RRUs are superimposed. and a processing unit 702, which is used to perform channel estimation on the acquired signals.

Optionally, the processing unit 702 specifically determines delays and Doppler shifts of downlink signals from each of a plurality of RRUs and delays and Doppler shifts for downlink signals of each RRU according to the delays and Doppler shifts. It is configured to perform frequency compensation, determine Wiener coefficients of the compensated signal, and perform channel estimation by using the Wiener coefficients.

Optionally, the receiving unit 701 specifically receives RRC dedicated signaling, wherein the first indicator bit in the RRC dedicated signaling is used to indicate that the UE is in a radio remote scenario. Receive or system message, wherein a second indicator bit in the system message is configured to receive a system message used to indicate that the UE is in a wireless remote scenario.

FIG. 8 is a structural diagram of a base station according to Embodiment 6 of the present invention. A base station is configured to perform the channel estimation method provided in the embodiments of the present invention. The base station comprises a communication interface 801, a memory 802 and a processor 803, the memory 802 being configured to store program instructions, and the processor 803 using the communication interface 801 according to the program instructions stored in the memory 802. and sending notification information to the UE indicating that the UE is in a wireless remote scenario by using the communication interface 801, wherein , the signaling information is used to instruct the UE to perform channel estimation by using a channel estimation algorithm applicable to the wireless remote scenario, the channel estimation algorithm superimposing downlink signals from multiple RRUs. and operations used to perform channel estimation on the signals obtained after they have been processed.

Optionally, the processor 803 performing operations to instruct the UE to perform channel estimation on signals obtained after the downlink signals from the multiple RRUs are superimposed, determining the delay and Doppler shift of the downlink signal of each RRU; performing delay and frequency compensation on the downlink signal of each RRU according to the delay and Doppler shift; and determining the Wiener coefficient of the compensated signal and performing channel estimation by using the Wiener coefficients.

Optionally, the processor 803 performing an operation of sending notification information to the UE indicating that the UE is in a wireless remote scenario, by using the communication interface 801, is dedicated to the RRC Signaling, the first indicator bit in the RRC dedicated signaling is used to indicate that the UE is in a radio remote scenario, sending RRC dedicated signaling to the UE, or using the communication interface 801 Thereby, a system message, wherein the second indicator bit in the system message comprises sending a system message to the UE, which is used to indicate that the UE is in a wireless remote scenario.

Optionally, the processor 803 is further, according to program instructions stored in the memory 802, prior to sending notification information to the UE indicating that the UE is in a wireless remote scenario by using the communication interface 801. It is configured to perform an operation to determine that it is in a fast moving state.

FIG. 9 is a structural diagram of a UE according to Embodiment 7 of the present invention. A UE is configured to perform the channel estimation method provided in the embodiments of the present invention. The UE comprises a communication interface 901, a memory 902 and a processor 903, the memory 902 being configured to store program instructions, the processor 903 using the communication interface 901 according to the program instructions stored in the memory 902. The signaling information indicates that the UE is in a wireless remote scenario by using a channel estimation algorithm applicable to the wireless remote scenario according to the operation and the signaling information. and an operation to perform channel estimation, wherein the channel estimation algorithm is used to perform channel estimation on a signal obtained after downlink signals from multiple RRUs are superimposed. configured to

Optionally, processor 903 performing an operation of performing channel estimation on a signal obtained after the downlink signals from the multiple RRUs are superimposed, the downlink signal from each of the multiple RRUs. determining a delay and Doppler shift; performing delay and frequency compensation on the downlink signal of each RRU according to the delay and Doppler shift; determining a Wiener coefficient of the compensated signal; and performing channel estimation by using.

Optionally, the processor 903 performing an operation of receiving notification information by using the communication interface 901, the notification information indicating that the UE is in a wireless remote scenario, receiving RRC dedicated signaling, wherein the first indicator bit in the RRC dedicated signaling is used to indicate that the UE is in a radio remote scenario, or receiving a system message, wherein a second indicator bit in the system message is used to indicate that the UE is in a wireless remote scenario, by using the communication interface 901; .

FIG. 10 is a structural diagram of a communication system according to Embodiment 8 of the present invention. A communication system is configured to perform the channel estimation method provided in the embodiments of the present invention. The system is a base station 1001 configured to establish a connection to a UE 1002 and send notification information to the UE 1002 indicating that the UE 1002 is in a wireless remote scenario, wherein the notification information is applicable to the wireless remote scenario. The channel estimation algorithm is used to instruct the UE 1002 to perform channel estimation by using a simple channel estimation algorithm, which performs channel estimation on signals obtained after downlink signals from multiple RRUs are superimposed. The base station 1001 used to perform the estimation, receiving signaling information from the base station 1001 indicating that the UE is in a wireless remote scenario, and according to the signaling information, the channel applicable to the wireless remote scenario. An estimation algorithm for performing channel estimation by using a channel estimation algorithm used to perform channel estimation on a signal obtained after downlink signals from multiple RRUs are superimposed. and a UE 1002 configured to:

Optionally, the UE 1002 specifically determines the delay and Doppler shift of the downlink signal from each of the plurality of RRUs and calculates the delay and frequency for the downlink signal of each RRU according to the delay and Doppler shift. It is configured to perform compensation, determine Wiener coefficients of the compensated signal, and perform channel estimation by using the Wiener coefficients.

Optionally, the base station 1001 specifically transmits RRC dedicated signaling, wherein the first indicator bit in the RRC dedicated signaling is used to indicate that the UE 1002 is in a radio remote scenario. Send to UE 1002, or a system message, wherein a second indicator bit in the system message is configured to send a system message to UE 1002, which is used to indicate that the UE is in a wireless remote scenario. .

Optionally, the base station 1001 is further configured to determine that the UE 1002 is in fast moving state before sending notification information to the UE 1002 indicating that the UE 1002 is in a wireless remote scenario.

Those skilled in the art will further recognize that the units and algorithm steps can be implemented by electronic hardware, computer software, or a combination thereof in combination with the examples described in the embodiments disclosed herein. I guess you are. To clearly illustrate the compatibility between hardware and software, the above generally described the configuration and steps of each example according to function. Whether a function is implemented in hardware or software depends on the particular application and design constraints of the technical solution. Skilled artisans may implement the described functionality for each particular application using different methods, but such implementations should not be viewed as exceeding the scope of the present invention.

Persons of ordinary skill in the art may understand that all or part of the steps in the above-described methods of the embodiments may be implemented by a program instructing a processor. The program may be stored on a computer-readable storage medium. Storage media include random access memory, read-only memory, flash memory, hard disk, solid state drive, magnetic tape, floppy (registered trademark) disk, optical disc (English : optical disc), or any combination thereof.

The above descriptions are only specific exemplary implementations of the present invention, and are not intended to limit the protection scope of the present invention. Any variation or replacement readily figured out by a person skilled in the art within the technical scope disclosed in the present invention should fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims (17)

A method of transmitting information,
transmitting radio resource control (RRC) dedicated signaling to a user equipment (UE) by a plurality of radio remote units (RRUs) of a base station, said RRC dedicated signaling being transmitted by two RRUs of said plurality of RRUs. is used to instruct the UE to perform channel estimation by using a channel estimation algorithm applicable to wireless remote scenarios in which the signs of the Doppler shifts of signals received by the UE from each of are opposite; The channel estimation algorithm is used to perform the channel estimation on signals obtained after the signals from the multiple RRUs are superimposed, wherein the multiple RRUs share the same cell identity. , stages and
transmitting the same signal to the UE by the multiple RRUs. 2. The method of claim 1, wherein the RRC dedicated signaling indicates that the UE is in the radio remote scenario. 3. The method of claim 2, wherein a first indicator bit in said RRC dedicated signaling indicates said UE is in said wireless remote scenario. A channel estimation method performed in a user equipment (UE), comprising:
receiving radio resource control (RRC) dedicated signaling, said RRC dedicated signaling being a Doppler shift of a signal received by said UE from each of two RRUs of a plurality of radio remote units (RRUs); is used for instructing the UE to perform channel estimation by using a channel estimation algorithm applicable to radio remote scenarios with opposite signs, the channel estimation algorithm comprising: used to perform said channel estimation on the signals obtained after being superimposed;
receiving the same signal transmitted from the plurality of RRUs sharing the same cell identity;
performing said channel estimation according to said RRC dedicated signaling. The step of performing channel estimation comprises:
determining delays and Doppler shifts of downlink signals from each of the plurality of RRUs;
performing delay and frequency compensation on the downlink signal of each RRU according to the delay and the Doppler shift;
5. The method of claim 4, comprising determining Wiener coefficients of a compensated signal and performing said channel estimation by using said Wiener coefficients. 6. A method according to claim 4 or 5, wherein said RRC dedicated signaling indicates said UE is in said radio remote scenario. 7. The method according to any one of claims 4-6, wherein a first indicator bit in said RRC dedicated signaling indicates that said UE is in said radio remote scenario. a base station,
A processing unit for controlling a plurality of radio remote units (RRUs) to transmit radio resource control (RRC) dedicated signaling to a user equipment (UE), wherein the RRC dedicated signaling is directed to two of the plurality of RRUs. for instructing the UE to perform channel estimation by using a channel estimation algorithm applicable to wireless remote scenarios where the signs of the Doppler shifts of the signals received by the UE from each of the RRUs are opposite. and the channel estimation algorithm comprises a processing unit used to perform the channel estimation on a signal obtained after the signals from the multiple RRUs are superimposed;
the plurality of RRUs are configured to transmit the same signal to the UE, and the plurality of RRUs share the same cell identity;
base station. 9. The base station of claim 8, wherein the RRC dedicated signaling indicates that the UE is in the radio remote scenario. 10. The base station of claim 9, wherein a first indicator bit in said RRC dedicated signaling indicates said UE is in said wireless remote scenario. A user equipment (UE),
A receiving unit configured to receive radio resource control (RRC) dedicated signaling, said RRC dedicated signaling being received by said UE from each of two RRUs of a plurality of radio remote units (RRUs). is used to instruct the UE to perform channel estimation by using a channel estimation algorithm applicable to wireless remote scenarios in which the sign of the Doppler shift of the signal is opposite, the channel estimation algorithm comprising: a receiving unit used to perform said channel estimation on signals obtained after signals from RRUs are superimposed;
a processing unit configured to perform said channel estimation according to said RRC dedicated signaling;
the receiving unit is further configured to receive the same signal transmitted from the plurality of RRUs sharing the same cell identity;
U.E. The processing unit determines delays and Doppler shifts of downlink signals from each of the plurality of RRUs and performs delay and frequency compensation on the downlink signals of each RRU according to the delays and the Doppler shifts. 12. The UE of claim 11, configured to perform the channel estimation by determining Wiener coefficients of a compensated signal and using the Wiener coefficients. 13. The UE according to claim 11 or 12, wherein said RRC dedicated signaling indicates said UE is in said radio remote scenario. 14. The UE according to any one of claims 11-13, wherein a first indicator bit in said RRC dedicated signaling indicates that said UE is in said radio remote scenario. A communication system,
comprising a base station and user equipment,
the base station in communication with the user equipment;
A system, wherein the base station performs the method according to any one of claims 1-3 and the user equipment performs the method according to any one of claims 4-7. A program that causes a computer to execute the method according to any one of claims 1 to 3. A program that causes a computer to execute the method according to any one of claims 4 to 7.

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