WO2012171292A1

WO2012171292A1 - Method, apparatus and device for switching between uplink mimo modes

Info

Publication number: WO2012171292A1
Application number: PCT/CN2011/081207
Authority: WO
Inventors: 郭军平; 李静
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-06-14
Filing date: 2011-10-24
Publication date: 2012-12-20
Also published as: CN102832980A; CN102832980B

Abstract

Disclosed are a method, an apparatus and a device for switching between uplink MIMO modes. The method comprises: upon obtaining that a transmitting manner used by a current transmission system is an MIMO manner, a base station determining a space correlation coefficient of two streams of uplink MIMO, and obtaining a received signal strength indication of each stream in a non-MIMO mode and a packet error ratio of each stream; selecting a smaller one of the received signal strength indications and a larger one of the packet error ratios of the two streams, and determining a corresponding uplink MIMO switching mode according to the space correlation coefficient of the two streams, and the selected received signal strength indication and packet error ratio. In the present invention, by comparing a space correlation coefficient, a selected smaller one of received signal strength indications and larger one of packet error ratios of two stream with a corresponding threshold value, an uplink MIMO switching mode is determined, and the uplink MIMO mode is switched, so better transmission performance is obtained.

Description

Method, device and device for switching between uplink MIMO modes

The present invention relates to the field of wireless communication technologies, and in particular, to a method, device, and device for switching between uplink multiple input multiple output (MIMO) modes. Background technique

MIMO technology is a key technology of the physical layer in Orthogonal Frequency Division Multiple Access (OFDMA) technology. MIMO technology refers to a technology in which a signal is spatially encoded and transmitted through multiple antennas in a wireless communication system, and then received by a plurality of antennas at the receiving end after being received by the wireless channel, and then the original signal is recovered by wireless space decoding. .

The MIMO technology application includes multiple implementations in the wireless communication system. Taking the WiMax system as an example, the implementation includes: multiple diversity technologies such as a transmit diversity mode, a spatial multiplexing mode, and a beamforming mode. For the receiving end, it is mainly multi-antenna receive diversity, which is limited by the number of antennas and capabilities of the terminal. Uplink MIMO mainly studies transmit diversity and spatial multiplexing. Various multi-antenna implementations are directed to different wireless channel environments. For example, when the spatial correlation between two streams of MIMO of a wireless channel is low, the system adopts spatial multiplexing to obtain better spectrum utilization and ensure transmission. Performance; When the spatial correlation between the two streams of MIMO is high, the system adopts the transmit diversity method to obtain better transmission performance. Thus the communication system can adaptively switch between different multi-antenna techniques depending on the conditions of the current channel.

There are many handover schemes for the downlink MIMO system, but it is limited by the capabilities of the terminal, and there is no perfect solution for the handover of the uplink MIMO system. Summary of the invention

In view of this, the present invention provides an uplink MIMO inter-mode handover method, apparatus, and device, and provides a handover method for an uplink MIMO system to obtain better transmission performance.

The present invention provides an uplink MIMO mode switching method, and the method includes the following steps:

When the transmission mode adopted by the current transmission system is MIMO, the base station performs channel estimation on the received signal to determine a spatial correlation coefficient of the two uplink MIMO streams;

Estimating the received signal strength indication of each current in non-MIMO mode;

Determining the packet error rate of each stream according to the number of current error packets per stream obtained by the check and the current number of packets of each stream obtained in the upper layer message;

The smaller value of the received signal strength indication of the two streams and the larger value of the packet error rate are selected, and the uplink MIMO switching mode is determined according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the packet error rate.

In the above solution, the method further includes: the base station notifying the terminal of the determined uplink MIMO mode after the handover.

In the foregoing solution, the determining a spatial correlation coefficient of two streams of the uplink MIMO includes: performing channel estimation on the received signal, determining an estimated channel impulse response value on each of the transmitting antennas and each receiving antenna, and obtaining a pilot. a channel impulse response matrix; performing an autocorrelation operation on the channel impulse response matrix of the pilot to obtain an autocorrelation matrix of the pilot; performing eigenvalue decomposition on the autocorrelation matrix of the pilot to obtain two uplink MIMO The spatial correlation coefficient of the stream.

In the foregoing solution, the determining, according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the error packet rate, determining an uplink MIMO switching mode, including:

Comparing the selected packet error rate with a set error packet rate threshold;

When the selected packet error rate is less than the set error packet rate threshold, according to the current uplink MIMO mode, and the comparison result between the spatial correlation coefficient of the two streams and the set correlation coefficient threshold, Determining the MIMO mode after switching;

When the selected packet error rate is greater than the set error packet rate threshold, the comparison result according to the current uplink MIMO mode, the spatial correlation coefficient of the two streams, and the set correlation coefficient threshold, and the selected received signal strength The result of the comparison with the set intensity indication threshold is indicated, and the MIMO mode after the switching is determined.

In the above solution, when the selected packet error rate is less than the set error packet rate threshold, determining the switched MIMO mode includes:

When determining that the current uplink MIMO mode is the MIMO-A mode, comparing the spatial correlation coefficient of the two streams with the set correlation coefficient threshold; when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold When the MIMO mode after the handover is determined to be the MIMO-B mode, when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, the MIMO-A mode is maintained;

When determining that the current uplink MIMO mode is the spatial multiplexing mode, comparing the spatial correlation coefficient of the two streams with the set correlation coefficient threshold; when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold When the set correlation coefficient threshold is increased, the MIMO-A mode is not switched, or the pair is not split. When the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, the MIMO is not switched. — A mode, or not split.

In the above solution, when the selected packet error rate is greater than a set error packet rate threshold, determining the switched MIMO mode includes:

When it is determined that the current uplink MIMO mode is the MIMO-A mode, the MIMO-A mode is maintained, and the terminal is notified to increase the transmit power;

When determining that the current uplink MIMO mode is the MIMO-B mode, comparing the spatial correlation coefficient of the two streams with the set correlation coefficient threshold; when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold When the MIMO mode after the handover is determined to be the MIMO-B mode, when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, the selected The received signal strength indication is compared with the set intensity indication threshold, and when the selected received signal strength indication is greater than the set intensity indication threshold, the correlation threshold is decreased, and the switched

The MIMO mode is MIMO-A mode. When the selected received signal strength indication is less than the set strength indication threshold, the terminal is notified to increase the transmission power and maintain the current MIMO mode.

In the above solution, when the selected packet error rate is greater than a set error packet rate threshold, determining the MIMO mode after the handover includes:

When it is determined that the current uplink MIMO mode is a cooperative MIMO mode, the spatial correlation coefficients of the two streams are compared with the set correlation coefficient threshold;

When the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, the terminal is notified to disassemble; when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, the selected received signal strength indication is to be selected. Comparing with the set intensity indication threshold, when the selected received signal strength indication is greater than the set intensity indication threshold, decreasing the correlation threshold, and determining to notify the terminal to disassemble, when the selected received signal strength indication is less than the setting The strength indicates a threshold, and the terminal is notified to increase the transmission power without disassembling.

The present invention further provides an uplink MIMO inter-mode switching apparatus, where the apparatus includes: a first determining module, configured to perform channel estimation on a received signal when determining that a transmission mode adopted by a current transmission system is a MIMO mode, and determining an uplink The spatial correlation coefficient of the two streams of MIMO;

An estimation module, configured to estimate a received signal strength indicator of each current in the non-MIMO mode;

a second determining module, configured to determine, according to the number of current error packets of each stream obtained by the check, and the current number of data packets of each stream obtained in the upper layer message, determining a packet error rate of each stream; For selecting a smaller value of the received signal strength indication of the two streams and a larger value of the packet error rate, determining uplink MIMO according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the error packet rate Switch mode. In the above solution, the device further includes:

The notification module is configured to notify the terminal of the determined uplink MIMO mode after the handover.

In the above solution, the first determining module is configured to perform channel estimation on the received signal, determine an estimated channel impulse response value on each of the transmitting antennas and each of the receiving antennas, and obtain a channel impulse response matrix of the pilot; Performing an autocorrelation operation on the channel impulse response matrix of the pilot to obtain an autocorrelation matrix of the pilot; performing eigenvalue decomposition on the autocorrelation matrix of the pilot to obtain spatial correlation coefficients of two streams of the uplink MIMO.

In the above solution, the comparison determining module is configured to compare the selected packet error rate with a set error packet rate threshold; when the selected packet error rate is less than a set error packet rate threshold, Determining a switched MIMO mode according to a current uplink MIMO mode, and a comparison result between a spatial correlation coefficient of the two streams and a set correlation coefficient threshold; when the selected packet error rate is greater than a set error packet rate threshold And determining, according to the current uplink MIMO mode, a comparison result between the spatial correlation coefficient of the two streams and the set correlation coefficient threshold, and a comparison result between the selected received signal strength indication and the set intensity indication threshold. MIMO mode.

In the above solution, the comparison determining module is configured to: when the selected error packet rate is less than the set error packet rate threshold, determine that the current uplink MIMO mode is the MIMO-A mode, and then spatially correlate the two streams The coefficient of the coefficient is compared with the set correlation coefficient threshold. When the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, the MIMO mode after the switching is determined to be the MIMO-B mode, when the space of the two streams When the correlation coefficient is greater than the set correlation coefficient threshold, the MIMO-A mode is maintained; when the current uplink MIMO mode is determined to be the spatial multiplexing mode, the spatial correlation coefficients of the two streams are compared with the set correlation coefficient threshold. And when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, increasing the set correlation coefficient threshold, not switching to the MIMO-A mode, or not splitting, when the two streams are When the spatial correlation coefficient is less than the set correlation coefficient threshold, it does not switch to the MIMO-A mode, or does not split.

In the above solution, the comparison determining module is configured to: when the selected packet error rate is greater than When determining the current packet error rate threshold, determining that the current uplink MIMO mode is MIMO-A mode, maintaining the MIMO-A mode, and notifying the terminal to increase the transmit power; determining that the current uplink MIMO mode is the MIMO-B mode, then the two streams are The spatial correlation coefficient is compared with the set correlation coefficient threshold. When the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, it is determined that the switched MIMO mode is MIMO-B mode, when two streams When the spatial correlation coefficient is less than the set correlation coefficient threshold, the selected received signal strength indication is compared with the set intensity indication threshold, and when the selected received signal strength indication is greater than the set intensity indication threshold, the reduction is performed. The correlation threshold is determined, and the switched MIMO mode is determined to be a MIMO-A mode. When the selected received signal strength indication is less than the set strength indication threshold, the terminal is notified to increase the transmit power and maintain the current MIMO mode.

In the above solution, the comparison determining module is configured to: when the selected packet error rate is greater than a set error packet rate threshold, determine that the current uplink MIMO mode is a cooperative MIMO mode, and then spatially correlate the two streams. The coefficient is compared with the set correlation coefficient threshold; when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, the terminal is notified to disassemble, when the spatial correlation coefficient of the two streams is less than the set correlation The threshold value of the selected coefficient is compared with the set intensity indication threshold. When the selected received signal strength indication is greater than the set intensity indication threshold, the correlation threshold is decreased, and the notification terminal is determined to be disassembled. For example, when the selected received signal strength indication is less than the set strength indication threshold, the terminal is notified to increase the transmit power without disassembling.

The present invention provides a base station, and the base station includes the above-described uplink MIMO inter-mode switching device.

The present invention provides a method, a device and a device for switching between uplink MIMO modes. When the transmission mode adopted by the current transmission system is MIMO, the base station performs channel estimation on the received signal to determine the spatial correlation between the two uplink MIMO streams. Coefficient; and obtain the received signal strength indication of each stream in non-MIMO mode and the packet error rate of each stream; select two streams The smaller value of the received signal strength indicator and the larger value of the packet error rate determine the uplink MIMO switching mode according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the packet error rate. In the present invention, the corresponding uplink MIMO switching mode is determined by comparing the spatial correlation coefficient of the two streams, the smaller value of the selected received signal strength indication, and the larger value of the error packet rate with the set corresponding threshold. Thus, mode switching of uplink MIMO is achieved, and thus, better transmission performance is obtained. DRAWINGS

The drawings are intended to provide a further understanding of the invention, and are intended to be a part of the invention. In the drawing:

1 is a schematic diagram of a process of switching between uplink MIMO modes according to the present invention; FIG. 2A is a schematic diagram of operation of two terminals of a single antenna in an uplink cooperative MIMO mode; FIG. 2B is a terminal uplink MIMO-A, MIMO with dual antennas. – a schematic diagram of the operation of the B mode;

FIG. 3 is a schematic diagram of a handover process of an uplink MIMO mode when the selected packet error rate is less than a set error packet rate threshold according to the present invention;

4 is a schematic diagram of a detailed process of switching between uplink MIMO modes with a packet error rate greater than a set error packet rate threshold provided by the present invention;

FIG. 5 is a schematic structural diagram of an apparatus for switching between uplink MIMO modes according to the present invention. detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments in order to make the present invention. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

1 is a schematic flowchart of a method for switching between uplink MIMO modes according to the present invention. The switching process includes the following steps:

S101: When obtaining the MIMO mode used by the current transmission system, the base station performs channel estimation on the received signal to determine a spatial correlation coefficient of the two uplink MIMO streams.

The base station obtains the transmission mode adopted by the current transmission system by directly reading the message of the Mac To Phy.

S102: The base station estimates a received signal strength indication of each current stream in the non-MIMO mode.

S103: The base station determines a packet error rate of each stream according to the number of current error data packets of each stream obtained by the check, and according to the current data packet number of each stream acquired in the upper layer message.

S104: Select a smaller value of the received signal strength indication of the two streams, and a larger value of the packet error rate, and determine an uplink MIMO handover according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the error packet rate. mode.

Here, after the base station determines the uplink MIMO handover mode, the determined handover uplink MIMO mode is also notified to the terminal.

The method for switching between uplink MIMO modes provided by the present invention is mainly for switching between MIMO modes of two streams of uplink MIMO, and can be applied to the switching process of the MIMO mode when the two terminals of the single terminal and the two antennas adopt the MIMO mode. .

FIG. 2A is a schematic diagram of the operation of the uplink cooperative MIMO mode of the two terminals of the single antenna, and FIG. 2B is a schematic diagram of the operation of the uplink MIMO-A and MIMO-B modes of the terminal having the dual antenna. In FIG. 2A, two users respectively use a single antenna terminal, and after the data of two users are encoded, the corresponding two terminals transmit user data to the base station in an uplink cooperative mode. In Figure 2B, the user uses a dual-antenna terminal, and the terminal encodes the user data, and the obtained encoded data is transmitted to the base station through MIMO-A mode or MIMO-B mode through space-time coding.

At present, the multi-antenna transmission technology adopted by the Wimax system mainly has the following types: 1. Inter-working multiplexing: The terminal adopts the BLAST structure, and the space-time coding matrix is

Using the transmit antenna to simultaneously transmit different signals to obtain doubled downlink traffic; 2. Uplink MIMO B and cooperative MIMO; 3, The work terminal adopts Alamouti-STC (Space Time Coding)

^S l —

A =

In the scheme, the space-time coding matrix is ^-S l , and the repeated signals are transmitted by the antenna to obtain the diversity gain. In addition, collaboration can also be combined with the uplink Α Α or ΜΙΜΟ Β 。. Different multi-antenna technology applications have different scenarios, and adaptive switching of multi-antenna technology can improve system performance.

In the present invention, the handover process of the MIMO mode needs to be determined according to the spatial correlation coefficient of the two streams of the uplink MIMO. Specifically, determining the spatial correlation of the two streams of the uplink MIMO is performing channel estimation on the received signal, and determining each transmit antenna. And estimating a channel impulse response on each receiving antenna to obtain a channel impulse response matrix of the pilot;

Performing an autocorrelation operation on the channel impulse response matrix of the pilot to obtain an autocorrelation matrix of the pilot;

Performing eigenvalue decomposition on the autocorrelation matrix of the pilot to obtain spatial correlation coefficients of two streams of uplink MIMO.

Specifically, when determining the spatial correlation coefficient of the two streams: first, channel estimation is performed on the received signal, and different channel estimation methods may be used. When performing channel estimation, each transmitting antenna and each receiving antenna need to be acquired. Channel impulse response estimate. The channel impulse response estimates obtained by the transmitting antenna and the receiving antenna are written in a matrix form to obtain a channel impulse response matrix of the pilot.

Performing an autocorrelation operation on the channel impulse response matrix of the obtained pilot to obtain a channel autocorrelation matrix of the pilot, and performing eigenvalue solving on the channel autocorrelation matrix, then the spatial correlation coefficient of the two streams is The result of solving the condition number of the channel autocorrelation matrix.

For example, the eigenvalue is defined as a solution satisfying the linear equation det(A - lI) = (), and the eigenvalues obtained by the solution are sorted, and the condition number cond ( A ) is defined as cond (A) = . When the channel is When the channel is uncorrelated, the autocorrelation matrix is a unit matrix, and the eigenvalues of the matrix are equal, and the obtained condition number is 1. When the channel is completely correlated, the autocorrelation matrix is an all-one matrix, and the matrix has only one non-zero feature. Value, then the condition number is ∞.

When obtaining the Received Signal Strength Indication (RSSI) of each stream, estimating the RSSI that is possible when each stream is not performing MIMO, and the RSSI indicates the degree of fading of the channel of the stream, where the RSSI may Obtained by the modular accumulation of the received signal.

When obtaining the packet error rate of each stream, the current number of error packets obtained according to the Cyclic Redundancy Check (CRC) and the current number of packets available in the upper layer information are used to obtain the current error of each stream. Package rate.

After the spatial correlation coefficient of the two streams is determined, and the received signal strength indication and the error packet rate are selected, the process of determining the corresponding MIMO switching mode according to the foregoing three parameters may include: selecting the selected packet The rate is compared with the set error rate threshold; when the selected packet error rate is less than the set error rate threshold, the current uplink MIMO mode and the spatial correlation coefficient of the two streams are related to the setting. The comparison result of the coefficient of the coefficient determines the MIMO mode after the switching; when the selected packet error rate is greater than the set error rate threshold, according to the current uplink MIMO mode, the spatial correlation coefficient of the two streams, and the set The result of the comparison of the correlation coefficient threshold and the comparison result of the selected received signal strength indication with the set intensity indication threshold determine the MIMO mode after the switching.

For convenience of explanation, the following is a description of the difference between the error packet rate and the set error packet rate threshold.

When the selected packet error rate is less than the set error packet rate threshold, determining the switched MIMO mode includes: when determining that the current uplink MIMO mode is the MIMO-A mode, setting the spatial correlation coefficient of the two streams The correlation coefficient threshold is compared; when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, it is determined that the switched MIMO mode is MIMO-B mode, when the spatial correlation coefficients of the two streams are greater than When setting the correlation coefficient threshold, keep MIMO-A mode;

When determining that the current uplink MIMO mode is the spatial multiplexing mode, comparing the spatial correlation coefficient of the two streams with the set correlation coefficient threshold; when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold When the set correlation coefficient threshold is increased, the MIMO-A mode is not switched, or the pair is not split. When the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, the MIMO is not switched. — A mode, or not split.

FIG. 3 is a process of switching the uplink MIMO mode when the selected packet error rate is less than the set error rate threshold, and the process includes the following steps:

S301: When obtaining the MIMO mode used by the current transmission system, the base station performs channel estimation on the received signal to determine a spatial correlation coefficient of the two uplink MIMO streams.

S302: Estimate the received signal strength indication of each current in the non-MIMO mode.

S303: Determine, according to the number of current error packets of each stream obtained by the check, and the current packet number of each stream obtained in the upper layer message, determine a packet error rate of each stream.

S304: Select a smaller value of the received signal strength indication of the two streams, and a larger value of the packet error rate.

S305: Compare the selected packet error rate with the set error packet rate threshold, and when the packet error rate is less than the set error packet rate threshold, and the terminal currently adopts the MIMO-A mode, proceed to step S306. When the terminal currently adopts the spatial multiplexing mode, step S309 is performed.

S306: Determine whether the spatial correlation coefficient of the two streams is greater than a set correlation coefficient threshold. When the determination result is yes, proceed to step S307; otherwise, proceed to step S308.

S307: It is determined that the terminal does not need to perform the MIMO mode switching. Therefore, the base station feeds back to the terminal the notification information that does not switch to the MIMO-B mode.

According to the channel correlation coefficient, the two stream spatial correlation coefficients are compared with the predetermined correlation coefficient threshold. If the correlation coefficients of the two streams are large, the spatial correlation between the two streams is strong, which is not suitable. MIMO mode for spatial multiplexing; conversely, if the correlation coefficients of the two streams are small, the current two streams are less correlated, which is suitable for spatial complexion. The MIMO mode used.

S308: The base station determines that the terminal needs to switch to the MIMO-B mode, and sends a notification message to the terminal to switch to the MIMO-B mode.

S309: Determine whether the spatial correlation coefficient of the two streams is greater than a set correlation coefficient threshold. When the determination result is yes, proceed to step S310; otherwise, proceed to step S311.

S310: The base station increases the set correlation coefficient threshold, determines that the terminal does not need to switch to the MIMO-A mode or does not perform the disassembly, and feeds back to the terminal not to switch to the MIMO-A mode or not to disassemble the notification information. .

S311: The base station determines that the terminal does not need to switch to the MIMO-A mode or does not perform the disassembly, and feeds back, to the terminal, the notification information that does not switch to the MIMO-A mode or does not perform the disassembly.

In the present invention, when the selected packet error rate is greater than the set error packet rate threshold and the current uplink MIMO mode is determined to be the MIMO-A mode or the MIMO-B mode, the process of determining the switched MIMO mode includes: When the current uplink MIMO mode is determined to be the MIMO-A mode, the MIMO-A mode is maintained, and the terminal is notified to increase the transmit power. When determining that the current uplink MIMO mode is the MIMO-B mode, the spatial correlation coefficients and settings of the two streams are set. The correlation coefficient threshold is compared; when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, it is determined that the switched MIMO mode is MIMO-B mode, when the spatial correlation coefficient of the two streams is less than When the correlation coefficient threshold is determined, the selected received signal strength indication is compared with the set intensity indication threshold, and when the selected received signal strength indication is greater than the set intensity indication threshold, the correlation threshold is decreased, and the determination is determined. The switched MIMO mode is MIMO-A mode, when the selected received signal strength indication is less than the set strength indication threshold, the notification End of the transmission power increase, and maintaining the current MIMO mode.

In addition, in the present invention, when determining that the current uplink MIMO mode is the cooperative MIMO mode, and the selected packet error rate is greater than the set error packet rate threshold, the process of determining the post-switching MIMO mode may include: The spatial correlation coefficient is compared with the set correlation coefficient threshold; When the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, the terminal is notified to disassemble, and when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, the selected received signal strength indication is to be selected. Comparing with the set intensity indication threshold, when the selected received signal strength indication is greater than the set intensity indication threshold, decreasing the correlation threshold, and determining to notify the terminal to disassemble, when the selected received signal strength indication is less than the setting The strength indicates a threshold, and the terminal is notified to increase the transmission power without disassembling.

4 is a schematic diagram of a detailed process of switching between uplink multiple input multiple output MIMO modes with a packet error rate greater than a set error packet rate threshold, and the handover process includes the following steps:

S401: The base station determines a transmission mode used by the current transmission system in the uplink. When it is determined that the current uplink adopts the MIMO mode, the process proceeds to step S402. Otherwise, the MIMO mode switch is not performed.

The base station obtains the transmission mode adopted by the current transmission system, which is obtained by directly reading the Mac To Phy message.

S402: Perform channel estimation on the received signal to determine a spatial correlation coefficient of the two uplink MIMO streams.

S403: Estimate the received signal strength indication of each current in the non-MIMO mode.

S404: Determine, according to the number of current error packets of each stream obtained by the check, and the current packet number of each stream obtained in the upper layer message, determine a packet error rate of each stream.

S405: Select a smaller value of the received signal strength indication of the two streams, and a larger value of the packet error rate. S406: Comparing the selected packet error rate with the set error packet rate threshold, and when the packet error rate is greater than the set error packet rate threshold, and the terminal currently adopts the MIMO-A mode, step S407 is performed. When the terminal currently adopts the MIMO-B mode, step S408 is performed, and when the terminal currently adopts the cooperative MIMO mode, step S413 is performed.

S407: The base station determines that the terminal needs to increase the transmit power, and does not need to switch to MIMO-B, that is, maintain the current MIMO-A mode, and notify the terminal to increase the transmit power, and keep the current MIMO-A mode.

S408: Determine whether the spatial correlation coefficient of the two streams is greater than a set correlation coefficient threshold. When the determination result is yes, proceed to step S409; otherwise, proceed to step S410.

S409: The base station determines that the terminal needs to switch to the MIMO-A mode, and sends a notification message to the terminal to switch to the MIMO A mode.

S410: Determine whether the currently selected RSSI is greater than the set RSSI threshold. When the determination result is yes, proceed to step S411; otherwise, proceed to step S412.

Comparing the selected RSSI with the predetermined RSSI threshold. If the selected RSSI is large, the fading degree of the channel through which the stream passes is small, and the terminal does not need to increase the transmission power or the modulation and coding reduction step. Otherwise, the terminal needs to increase the transmission. Power or modulation coding reduced order processing.

S411: Increase the set correlation coefficient threshold, and determine that the terminal needs to switch to the MIMO-A mode. Therefore, at this time, the base station sends the terminal to the terminal to switch to the MIMO-A mode notification information.

S412: Determine that the terminal needs to increase the transmit power, and does not need to switch to MIMO-B, that is, maintain the current MIMO-A mode. Therefore, the base station notifies the terminal to increase the transmit power and maintain the current MIMO-A mode.

S413: Determine whether the spatial correlation coefficient of the two streams is greater than a set correlation coefficient threshold. When the determination result is yes, proceed to step S414; otherwise, proceed to step S415.

S414: The base station determines that the terminal is disconnected, does not perform the cooperative MIMO mode, and sends the terminal with the notification information of the split and non-cooperative MIMO mode.

S415: Determine whether the currently selected RSSI is greater than the set RSSI threshold. When the determination result is yes, proceed to step S416; otherwise, proceed to step S417.

S416: The base station increases the set correlation coefficient threshold, determines that the terminal is disconnected, does not perform the cooperative MIMO-A mode, and sends the terminal information to the terminal to disassemble and not perform the cooperative MIMO mode. S417: The base station determines that the terminal needs to increase the transmit power, and does not need to disassemble, notify the terminal to increase the transmit power, and maintain the current cooperative MIMO-A mode.

FIG. 5 is a schematic structural diagram of an apparatus for switching between uplink MIMO modes according to the present disclosure. The apparatus includes: a first determining module 51, configured to: when acquiring a transmission mode adopted by the current transmission system into a MIMO mode, receiving a signal Performing channel estimation to determine a spatial correlation coefficient of two streams of the uplink MIMO; an estimation module 52, configured to estimate a received signal strength indication of each current in the non-MIMO mode; and a second determining module 53 configured to obtain, according to the verification, The current error packet number of each stream, and the current data packet number of each stream obtained in the upper layer message, determining the packet error rate of each stream; the comparison determining module 54 is configured to select the received signals of the two streams. The smaller value of the strength indication and the larger value of the packet error rate determine the uplink MIMO switching mode according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the packet error rate.

The apparatus further includes: a notification module 55, configured to notify the terminal of the determined switched uplink MIMO mode.

The first determining module 51 may be configured to perform channel estimation on the received signal, determine an estimated channel impulse response value on each of the transmitting antennas and each of the receiving antennas, and obtain a channel impulse response matrix of the pilot; The channel impulse response matrix performs an autocorrelation operation to obtain an autocorrelation matrix of the pilot; performing eigenvalue decomposition on the autocorrelation matrix of the pilot to obtain spatial correlation coefficients of the two streams of the uplink MIMO.

The comparison determining module 54 is configured to compare the selected packet error rate with the set error packet rate threshold; when the selected packet error rate is less than the set error packet rate threshold, according to the current uplink MIMO mode And comparing the spatial correlation coefficient of the two streams with the set correlation coefficient threshold to determine the switched MIMO mode; when the selected packet error rate is greater than the set error rate threshold, according to the current uplink The MIMO mode, the comparison result of the spatial correlation coefficient between the two streams and the set correlation coefficient threshold, and the comparison result between the selected received signal strength indication and the set intensity indication threshold determine the MIMO mode after the switching. The comparison determining module 54 is configured to: when the selected packet error rate is less than the set error packet rate threshold, determine that the current uplink MIMO mode is the MIMO-A mode, and set the spatial correlation coefficient and the setting of the two streams. The correlation coefficient threshold is compared. When the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, it is determined that the switched MIMO mode is MIMO-B mode, and the spatial correlation coefficient of the two streams is greater than When the correlation coefficient threshold is determined, the MIMO_A mode is maintained; when the current uplink MIMO mode is determined to be the spatial multiplexing mode, the spatial correlation coefficients of the two streams are compared with the set correlation coefficient threshold, when the two streams are When the spatial correlation coefficient is greater than the set correlation coefficient threshold, the set correlation coefficient threshold is increased, and the MIMO-A mode is not switched, or the pair is not split, when the spatial correlation coefficients of the two streams are smaller than When the correlation coefficient threshold is set, it does not switch to MIMO-A mode, or does not split.

The comparison determining module 54 may be configured to determine that the current uplink MIMO mode is MIMO when determining that the current uplink MIMO mode is MIMO_A mode or MIMO-B mode and the selected packet error rate is greater than a set error packet rate threshold. In the A mode, the MIMO-A mode is maintained, and the terminal is notified to increase the transmit power. When the current uplink MIMO mode is determined to be the MIMO-B mode, the spatial correlation coefficients of the two streams are compared with the set correlation coefficient threshold. When the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, determining that the switched MIMO mode is a MIMO-B mode, when the spatial correlation coefficients of the two streams are less than a set correlation coefficient threshold, And comparing the selected received signal strength indication with the set strength indication threshold, decreasing the correlation threshold when the selected received signal strength indication is greater than the set strength indication threshold, and determining that the switched MIMO mode is MIMO— In the mode A, when the selected received signal strength indication is less than the set strength indication threshold, the terminal is notified to increase the transmission power, and Holding current MIMO mode.

The comparison determining module 54 is configured to: when determining that the current uplink MIMO mode is a cooperative MIMO mode and the selected packet error rate is greater than a set error packet rate threshold, correlating the spatial correlation coefficients of the two streams with the setting The coefficient of the coefficient is compared, when the spatial correlation coefficient of the two streams is large When the set correlation coefficient threshold is set, the terminal is notified to be disassembled, and when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, the selected received signal strength indication is compared with the set intensity indication threshold. And when the selected received signal strength indication is greater than the set strength indication threshold, the correlation threshold is decreased, and the notification terminal is determined to be disassembled, and when the selected received signal strength indication is less than the set strength indication threshold, the terminal is notified to increase the transmission. Power, not split.

Specifically, the above device may be located in a base station.

The present invention provides a method, a device and a device for switching between uplink MIMO modes. In this method, when the transmission mode adopted by the current transmission system is MIMO, the base station performs channel estimation on the received signal to determine two uplink MIMO. The spatial correlation coefficient of the stream; and obtaining the received signal strength indication of each stream in the non-MIMO mode and the packet error rate of each stream; selecting the smaller value of the received signal strength indication of the two streams, and the packet error rate The larger value determines the uplink MIMO switching mode after the handover according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the packet error rate. In the present invention, the uplink MIMO switching after the handover is determined by comparing the spatial correlation coefficient of the two streams, the smaller value of the selected received signal strength indication, and the larger value of the error packet rate with the set corresponding threshold. Mode, thus achieving mode switching of uplink MIMO, and thus obtaining better transmission performance.

The above description shows and describes a preferred embodiment of the present invention, but as described above, it should be understood that the present invention is not limited to the forms disclosed herein, and should not be construed as Other combinations, modifications, and environments are possible and can be modified by the teachings or related art or knowledge within the scope of the inventive concept described herein. All changes and modifications made by those skilled in the art are intended to be within the scope of the appended claims.

Claims

Claim

An uplink multi-input multiple-output MIMO inter-mode switching method, the method comprising:

2. The method according to claim 1, wherein the method further comprises: the base station notifying the terminal of the determined switched uplink MIMO mode.

The method according to claim 1, wherein the determining a spatial correlation coefficient of the two uplink MIMO streams includes:

Performing channel estimation on the received signal, determining channel impulse response estimation values on each of the transmitting antennas and each receiving antenna, obtaining a channel impulse response matrix of the pilot; performing autocorrelation on the channel impulse response matrix of the pilot Computing, obtaining an autocorrelation matrix of the pilot; performing eigenvalue decomposition on the autocorrelation matrix of the pilot to obtain spatial correlation coefficients of the two streams of the uplink MIMO.

The method according to claim 1, wherein the determining the uplink MIMO switching mode according to the spatial correlation coefficient of the two streams, the selected received signal strength indicator, and the error packet rate includes:

The method according to claim 4, wherein, when the selected packet error rate is less than a set error packet rate threshold, determining the switched MIMO mode comprises:

The method according to claim 4, wherein, when the selected packet error rate is greater than a set error packet rate threshold, determining the switched MIMO mode comprises:

An apparatus for switching between uplink MIMO modes, wherein the apparatus includes: a first determining module, configured to perform channel estimation on a received signal when obtaining a transmission mode adopted by a current transmission system to be a MIMO mode, The spatial correlation coefficient of two streams of uplink MIMO;

a second determining module, configured to determine, according to the number of current error packets of each stream obtained by the check, and the current number of data packets of each stream obtained in the upper layer message, determining a packet error rate of each stream; For selecting a smaller value of the received signal strength indication of the two streams and a larger value of the packet error rate, determining uplink MIMO according to the spatial correlation coefficient of the two streams, the selected received signal strength indication, and the error packet rate Switch mode.

The device according to claim 8, wherein the device further comprises: a notification module, configured to notify the terminal of the determined switched uplink MIMO mode.

The device according to claim 8, wherein the first determining module is configured to perform channel estimation on the received signal, and determine an estimated channel impulse response value on each of the transmitting antennas and each of the receiving antennas. Obtaining a channel impulse response matrix of the pilot; performing an autocorrelation operation on the channel impulse response matrix of the pilot to obtain an autocorrelation matrix of the pilot; performing eigenvalue decomposition on the autocorrelation matrix of the pilot to obtain an uplink The spatial correlation coefficient of the two streams of MIMO.

The device according to claim 8, wherein the comparison determining module is configured to compare the selected packet error rate with a set error packet rate threshold; when the packet error rate is selected When the value is less than the set error rate threshold, the MIMO mode after the handover is determined according to the current uplink MIMO mode and the comparison result between the spatial correlation coefficient of the two streams and the set correlation coefficient threshold; When the packet rate is greater than the set error rate threshold, the comparison result between the current uplink MIMO mode, the spatial correlation coefficient of the two streams, and the set correlation coefficient threshold, and the selected received signal strength indication and the set strength The comparison result indicating the threshold determines the MIMO mode after the handover.

The device according to claim 11, wherein the comparison determining module is configured to determine that the current uplink MIMO mode is MIMO-A when the selected packet error rate is less than a set error packet rate threshold. The mode compares the spatial correlation coefficient of the two streams with the set correlation coefficient threshold, and determines that the switched MIMO mode is MIMO when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold. – B mode, when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, the MIMO-A mode is maintained; when the current uplink MIMO mode is determined to be the spatial multiplexing mode, the spatial correlation coefficients of the two streams are determined Comparing with the set correlation coefficient threshold, when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, increasing the set correlation coefficient threshold, and not switching to the MIMO-A mode, Or not split, when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, do not switch to MIMO-A mode, or not split.

The apparatus according to claim 11, wherein the comparison determining module is configured to determine that the current uplink MIMO mode is MIMO-A when the selected packet error rate is greater than a set error packet rate threshold. In the mode, the MIMO-A mode is maintained, and the terminal is notified to increase the transmit power. When the current uplink MIMO mode is determined to be the MIMO-B mode, the spatial correlation coefficients of the two streams are compared with the set correlation coefficient threshold. When the spatial correlation coefficient of the stream is greater than the set correlation coefficient threshold, it is determined that the switched MIMO mode is the MIMO-B mode, and when the spatial correlation coefficient of the two streams is less than the set correlation coefficient threshold, the selection is selected. The received signal strength indication is compared with the set strength indication threshold. When the selected received signal strength indication is greater than the set strength indication threshold, the correlation threshold is decreased, and the switched MIMO mode is determined to be MIMO-A mode. And when the selected received signal strength indication is less than the set strength indication threshold, notifying the terminal to increase the transmit power, and maintaining the current MIMO mode.

The device according to claim 11, wherein the comparison determining module is configured to determine that the current uplink MIMO mode is a cooperative MIMO mode when the selected packet error rate is greater than a set error packet rate threshold. And comparing the spatial correlation coefficient of the two streams with the set correlation coefficient threshold; when the spatial correlation coefficient of the two streams is greater than the set correlation coefficient threshold, the terminal is notified to disassemble, when the two streams When the spatial correlation coefficient is less than the set correlation coefficient threshold, the selected received signal strength indication is compared with the set intensity indication threshold, and when the selected received signal strength indication is greater than the set intensity indication threshold, the reduction is performed. The correlation threshold is determined, and the notification terminal is disassembled. When the selected received signal strength indication is less than the set strength indication threshold, the terminal is notified to increase the transmission power without disassembling.

A base station, characterized in that the base station comprises the apparatus according to any one of claims 8 to 14.