WO2011003291A1

WO2011003291A1 - Antenna selection method for mobile terminal and system

Info

Publication number: WO2011003291A1
Application number: PCT/CN2010/071777
Authority: WO
Inventors: 支周; 于辉; 魏巍; 郭阳; 卢忱
Original assignee: 中兴通讯股份有限公司
Priority date: 2009-07-08
Filing date: 2010-04-14
Publication date: 2011-01-13
Also published as: CN101944940A

Abstract

An antenna selection method for mobile terminal and a system are used for solving the technical problem of antenna selection in the LTE-A protocol edition. Taking power saving and cost of the terminal into account, the method of the present invention divides 4 antennae into groups, and orders the antennae according to results of their channel quality estimations, accordingly selects one group of two antennae with the best channel quality estimation to transmit. The present invention can use the antenna selection signaling of the LTE-A release 8 protocol edition, modify the system little, and the overhead of signaling is little. The present invention can also support a flexible antenna grouping mode by adding downlink control information (DCI), thereby enhances the sensitivity to channel quality and the transmission performance.

Description

Antenna selection method and system for mobile terminal

The present invention relates to the field of mobile communications, and in particular, to an antenna selection method and apparatus for a mobile terminal. Background technique

The Long Term Evolution (LTE) system is an important program for third-generation partner organizations. Orthogonal Frequency Division Multiplexing (OFDM) is one of the core technologies in the fourth generation of mobile communication, which is essentially a multi-carrier modulation communication technology. MIMO (Multi-Input Multi-Output) technology can increase system capacity, improve transmission performance, and integrate well with other physical layer technologies, thus becoming a key technology for B3G and 4G mobile communication systems. However, when the channel correlation is strong, the diversity gain and multiplexing gain caused by the multipath channel are greatly reduced, resulting in a significant degradation of the performance of the MIMO system.

In the MIMO system, the system throughput gain is also brought about, the hardware and signal processing complexity is increased, the transceiver size is increased, and more RF circuits, frequency down converters, beam converters, etc. are required.

The selection of the transmitting antenna is to judge the channel state information, and the antenna selection technique selects an antenna with a better channel state (acceptable) to transmit the corresponding service signal, and the antenna with other channel state is not good (cannot be accepted) is turned off or only Used to send pilots without sending traffic signals. In the worst case, at least one antenna can be guaranteed to work normally to keep the link of the communication system unblocked. Especially for power sensitive devices such as terminals, antenna selection has more important significance. The RF circuit is an important part of the cost of the mobile terminal/User Equipment (UE). Through the antenna selection technology, the number of amplifiers can be reduced, and the cost of the UE can be reduced. Low power consumption and reduced complexity. The UE transmits a reference measurement signal on the uplink antenna, and the reference measurement signal transmitted by the LTE uplink includes a Demodulation Reference Signal (DM RS) and a Sounding Refrence Signal (SRS), and arranges the SRS in a suitable position. On the uplink, the eNodeB learns the uplink channel information according to the uplink pilot, and then determines and notifies the UE to select the corresponding antenna with good channel quality.

In the LTE release8 protocol version, the UE has two transmit antennas, one PA (power amplifier), and the PA is alternately transmitted through two antennas. This has the advantage of avoiding long-term fading of the signal, and selecting spatial channels of different qualities, increasing the uplink transmit gain, and saving the manufacturing cost of the UE and improving the power-saving performance of the terminal. The antenna selection execution process is: the UE transmits the uplink SRS, and alternately transmits on the two antennas according to the specification, and the eNodeB estimates the uplink channel quality of the two antennas according to the received SRS signal, and then the eNodeB is implicitly (through 36.212 8605.3. 3.2 CRC attachment ) informs the UE to select a good antenna to transmit.

In the current LTE-Adcance (LTE-A) protocol version, the uplink supports up to 4 antennas. This may configure 4 PAs or 2 PAs in the terminal, 4 antennas for reception when receiving, and 4 PAs for transmission when transmitting. Or 2 PAs are sent, but the antenna selection is not clearly defined in the existing LTE-A protocol version. Summary of the invention

In view of this, the main object of the present invention is to provide an antenna selection method and apparatus for a mobile terminal, which are used to solve the technical problem of how the user equipment performs antenna selection in the LTE-A system.

In order to achieve the above object, the technical solution of the present invention is achieved as follows:

An antenna selection method for a mobile terminal, comprising: The enhanced base station eNodeB estimates the uplink channel quality of each antenna according to the reported uplink reference measurement signal, determines the antenna packet with the best uplink channel quality, and notifies the UE of the decision result;

The UE selects the corresponding antenna packet for transmission according to the decision of the eNodeB.

Further, the antenna group is a fixed packet, and the eNodeB estimates the uplink channel quality of each antenna group in units of fixed antenna packets, and determines that the antenna packet with the best uplink channel quality is notified to the UE.

Further, the antenna packet includes two fixed antenna packets, and the uplink reference measurement signals of the two antenna packets are reported to the eNodeB in two consecutive subframes respectively; the eNodeB estimates the uplink channel quality of each antenna packet separately, After the uplink channel quality estimation of the second antenna group is completed, the uplink channel quality evaluation results of the two antenna groups are compared, and the antenna packet with the best uplink channel quality is selected and notified to the UE.

Further, the antenna packet includes two fixed antenna packets, and the uplink reference measurement signals of the two antenna packets are respectively reported to the eNodeB on different time slots of the same subframe; the eNodeB receives two antenna packets in the same subframe. After the uplink reference measurement signal, the uplink channel quality of each antenna group is estimated, and the uplink channel quality evaluation results of the two antenna groups are compared, and the antenna packet with the best uplink channel quality is selected and notified to the UE.

Further, the antenna group is a non-fixed packet, and the system indicates different combinations of antenna packets by adding new downlink control information; after receiving the uplink reference measurement signal reported by each antenna packet, the eNodeB separately uplinks each antenna The channel quality is estimated, and then the uplink channel quality of each antenna is sorted, and the antenna with the best uplink channel quality is selected to form a new antenna packet, and the determined new antenna packet is notified to the mobile by the added downlink control information. terminal.

Further, the antenna packet includes two non-fixed antenna packets, and the uplink reference measurement signals of the two antenna packets are respectively in two consecutive subframes or respectively in the same subframe. The time slot is reported to the eNodeB.

The present invention further provides a mobile terminal antenna selection system based on the above method, and the technical solution of the present invention is implemented as follows:

A mobile terminal antenna selection system includes:

a grouping unit, located at the UE end, for initial grouping the uplink antennas;

a measurement reporting unit, located at the UE, configured to map an uplink reference measurement signal into each subframe in units of antenna packets;

Selecting a transmitting unit, located at the UE end, for selecting a corresponding antenna to transmit according to the antenna group determined by the grouping unit or the channel notifying unit;

The uplink channel quality estimation unit is located at the eNodeB, and is configured to estimate an uplink channel quality of each antenna according to the uplink reference measurement signal reported by the measurement reporting unit, and determine an antenna packet with the best uplink channel quality;

The channel notification unit, located at the eNodeB, is configured to notify the UE of the antenna packet with the best uplink channel quality determined by the eNodeB.

Further, the antenna group is a fixed packet, and the uplink channel quality estimation unit estimates an uplink channel quality of each antenna group in units of fixed antenna packets, and determines an uplink channel quality of the eNodeB by using a channel notification unit. The antenna group is notified to the UE.

Further, the UE includes two fixed antenna packets, and the measurement reporting unit maps the uplink reference measurement signals on two consecutive subframes or on different time slots of the same subframe through two antenna groups to the eNodeB.

Further, the antenna grouping is a non-fixed packet, and the system indicates different combinations of antenna packets by adding new downlink control information; the uplink channel quality estimating unit separately estimates the uplink channel quality of each antenna, and then for each antenna. The uplink channel quality is sorted, and the antenna with the best uplink channel quality is selected to form a new antenna packet, and the channel notification unit notifies the UE of the new antenna packet by the added downlink control information. Further, the UE includes two non-fixed antenna packets, and the measurement reporting unit reports the uplink reference measurement signal to the eNodeB through two antenna packets on two consecutive subframes or different time slots of the same subframe.

The present invention also proposes a mobile terminal antenna selection method in a scenario in which channel reciprocity is available in a time division duplex system, and the technical solution of the present invention is implemented as follows:

A method for selecting an antenna of a mobile terminal includes the steps of:

The eNodeB sends a downlink reference measurement signal to the UE, and the UE receives the downlink reference measurement signal; the UE estimates the downlink channel quality according to the downlink reference measurement signal, and infers the uplink channel quality based on the channel reciprocity;

The UE selects an antenna packet with better uplink channel quality for transmission based on the inferred uplink channel quality autonomous decision.

Based on the foregoing method for selecting a mobile terminal antenna in a scenario in which channel reciprocity is available in a time division duplex system, the present invention further provides a mobile terminal antenna selection system, including:

a downlink reference measurement signal sending module, located at the eNodeB end, configured to send a downlink reference measurement signal to the UE;

An uplink channel quality inference module, located at the UE end, is configured to estimate a downlink channel quality according to the downlink reference measurement signal, and infer an uplink channel quality;

The decision module is located at the UE end for selecting an antenna packet having a better uplink channel quality according to the inferred uplink channel quality autonomous decision.

The present invention considers the power saving of the terminal and the cost problem, and groups the four antennas or sorts the channel quality estimation results thereof, thereby selecting one set or two antennas with the best channel quality estimation for transmission, and the present invention can In the LTE-A system, the antenna selection signaling in the LTE release 8 is extended, and the modification to the system is small, and the signaling overhead is small. In addition, the present invention can also support flexible antenna grouping by increasing DCI, thereby improving sensitivity to channel quality and enhancing transmission performance. At the same time, the invention can also avoid long-term fading, obtain diversity gain, and reduce cost. DRAWINGS

FIG. 1 is a schematic diagram of a method for assisting a UE to perform antenna selection by using an eNodeB according to the present invention; FIG. 2 is an antenna selection process for reusing LTE release 8 antenna selection signaling indication in an FDD mode;

Figure 4 shows the flow of the antenna selection by the terminal by adding a new DCI in the FDD mode;

5 is a schematic diagram of an uplink reference measurement signal for transmitting each antenna group in different time slots in the same subframe on four antennas according to the present invention;

6 is a schematic diagram of antenna selection by using channel reciprocity in the TDD mode of the present invention; FIG. 7 is a flowchart of autonomous antenna selection based on channel reciprocity in the TDD mode of the present invention; FIG. 8 is a channel that cannot be utilized in the TDD mode of the present invention; A flowchart for indicating the antenna selection by the terminal through the newly added DCI during reciprocity;

FIG. 9 is a logic structural diagram of a mobile terminal antenna selection system according to the present invention. BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be further described in detail below with reference to the accompanying drawings.

For the FDD (Frequency Division Duplex) system, the schematic diagram of the antenna selection method that needs to be implemented by the eNodeB is shown in Figure 1. The main process is: The UE sends a measurement signal to the eNodeB, and the eNodeB estimates the uplink channel quality according to the uplink reference measurement signal, and the decision is made. The UE is then notified of the result, and the UE transmits the channel with better channel quality according to the decision result.

The following implementation has four transmit antennas at the transmitting end, and two PAs are taken as an example. However, in the case that the UE has more transmit antennas, the idea of antenna grouping can still be considered, thereby saving control signaling overhead. Example 1:

In this embodiment, the UE is in the FDD mode. The embodiment uses the LTE release8 antenna selection signaling to instruct the terminal to select the antenna group with the corresponding channel quality for combined transmission. As shown in FIG. 2, the specific steps are as follows:

Step 201: Perform grouping on uplink transmit antennas of the UE.

Grouping the antennas may be based on certain set principles, for example, based on antenna correlation, capacity, and the like. In this embodiment, the antenna correlation principle is adopted, and the uplink antennas of the UE are grouped, and two antennas with less correlation are selected as a group, and two groups are used. The packets in this embodiment are fixed packets, and each subframe is in each subframe. The two antennas of a group are always transmitted and received as a whole.

Step 202: Send an uplink reference measurement signal to the eNodeB in units of antenna groups in each subframe according to the antenna grouping.

The uplink reference measurement signals may be transmitted on a group of antennas in each subframe or the uplink reference measurement signals of the respective antenna groups may be separately transmitted in different time slots in each subframe. Various modes are described below with reference to the accompanying drawings:

As shown in FIG. 3, T1, Τ2, Τ3, Τ4, Τ5 respectively represent one subframe, and Txl, Tx2, Τχ3, Τχ4 respectively represent four transmitting antennas, and the UE includes two sets of radio frequency units, and at the same time, two antennas can be allowed to be transmitted. In this embodiment, four antennas are grouped into (Txl, Tx3), (Τχ2, Τχ4), and the radio unit can be switched between two sets of transmitting antennas (Txl, Tx3) (Τχ2, Τχ4) by switching. As shown in FIG. 3, in the T1 subframe, the uplink reference measurement signal and data are transmitted on (Tx1, Tx3), and in the Τ2 subframe, one time slot is switched to (Τχ2, Τχ4) to transmit the uplink reference measurement signal. The eNodeB compares the uplink channel quality estimation results of the two antenna groups in the T2 subframe, and then selects a group of antenna groups with better uplink channel quality estimation results to notify the UE, and the eNodeB delays to use the newly selected antenna in the next subframe. Combined launch. The method is characterized in that a fixed antenna grouping is used, since an uplink reference measurement signal is sent by selecting a group of antennas in each time slot. No. The LTE Release 8 control signaling can be used to directly notify the UE of the selected antenna group, which has less modification to the existing system and less occupied channel resources.

Step 203: The eNodeB estimates channel quality of the two groups of antennas according to the latest uplink reference measurement signals of the two groups of antennas, and determines, according to the estimation result, which antenna group has better channel quality.

Step 204: The eNodeB uses the LTE release8 mode to notify the UE to select an antenna group with a corresponding good channel quality to transmit in the next subframe according to the judgment result.

Step 205: After receiving the notification of the eNodeB received by the UE, select the corresponding antenna group to transmit according to the instruction of the eNodeB.

Optionally, if the control signaling allows, there are enough control bits, and the non-stationary packet mode may be adopted. In each subframe, the uplink reference measurement signals of the two antennas are reported each time according to the initial packet, and the eNodeB performs channel quality estimation. And selecting two antennas with good channel quality from the four antennas to form a group, and notifying the corresponding antenna group to the UE by using control signaling, and the UE transmitting the uplink reference measurement signal on the newly determined antenna group of the eNodeB in the next subframe, In the next sub-frame, the other two antennas transmit the uplink reference measurement signal, and so on, and the loop is executed.

Example 2:

In this embodiment, in the FDD mode, the antenna selection is implemented by adding new downlink control information (Downlink Control Information, DCI), that is, adding six states of antenna selection indication information. As shown in FIG. 4, the specific process is as follows:

Step 401: Perform grouping on uplink transmit antennas of the UE.

In this embodiment, the non-stationary grouping mode is adopted, and the antenna selection instruction information of the six states is added to indicate which two antennas are specifically selected for transmission. Test signal

Step 403: The eNodeB estimates, according to the received uplink reference measurement signal, in each subframe. Uplink channel quality; sorting four antennas according to the estimation result;

Step 404: The eNodeB comprehensively determines, according to the sorting result, which two antennas have higher quality of the transmitting antenna, and notifies the UE by using the antenna selection indication information;

Step 405: The UE selects a corresponding transmit antenna according to the antenna selection indication information.

In this embodiment, the selection determining process of the antenna in each subframe is as shown in FIG. 5, T1, Τ2, Τ3, Τ4, Τ5 respectively represent one subframe, and Txl, Τχ2, Τχ3, Τχ4 respectively represent four transmitting antennas. The UE includes two sets of radio frequency units, and at the same time, two antennas can be allowed to transmit. In the initial case, (Txl, Tx3) is taken as a group, and (Τχ2, Τχ4) is taken as a group, in each subframe, the UE The respective uplink reference measurement signals are respectively transmitted on the four antennas of the two sets of antennas in units of antenna groups, and it is assumed that in the Τ2 subframe, the eNodeB estimates the uplink channel quality of each antenna according to the received uplink reference measurement signal, and according to The estimation result sorts the four antennas, and the result of the ranking is that the uplink channel quality of Tx2 and Τχ3 is the best, and the eNodeB notifies the UE by the antenna selection indication information. Since the notification process requires a certain delay, the UE is in the T4 subframe, according to The indication of the antenna selection indication information selects a new antenna group (Tx2, Τχ3) for uplink reference measurement signal and data transmission, And in the different time slots of the same subframe, the uplink reference measurement signals of the other two antennas are transmitted on the other two antennas, and so on, and executed cyclically.

The feature of this method is that the antenna selection is better in real-time, but the occupied channel resources are more than in the case of fixed packets.

Optionally, the embodiment may also adopt a fixed grouping manner, and the eNodeB performs uplink channel quality evaluation based on the antenna group, and selects a group of antennas with better quality to notify the UE, and if the fixed grouping is used, the new DCI may not be added. The control antenna of the LTE Release 8 can be directly used to notify the UE of the selected antenna group, which has less modification to the existing system and less occupied channel resources.

For the TDD (Time Division Duplex) system, in the scenario in which the channel reciprocity can be utilized, a schematic diagram of implementing the antenna selection method is shown in FIG. 6. The UE estimates the downlink channel quality according to the received downlink reference symbols, according to the TDD channel reciprocity. Characteristic, infer the channel quality of the uplink transmit antenna The situation, and based on certain criteria, capacity, antenna correlation, etc., make a final decision. Such a process can be completed on the UE side without the need for eNodeB assistance.

Implementation 3:

The TDD mode UE is based on the reciprocity autonomous antenna selection process, as shown in FIG. 7: Step 701: The eNodeB sends a downlink reference measurement signal to the UE, and the UE receives the downlink reference measurement signal.

Step 702: The UE estimates the downlink channel quality by using a channel reciprocity characteristic of the TDD system, and infers the uplink channel quality.

Step 703: The UE autonomously decides to select an antenna packet with better uplink channel quality for transmission.

For the TDD system, if the UE cannot use the channel reciprocity in some scenarios (such as the Doppler shift environment), the uplink channel measurement can be implemented in a similar manner to FDD. One option is to consider the uplink four antennas as two antenna packets. For such antenna selection, the antenna signaling mode of the LTE release 8 can be reused, so that no change is required for the LTE release 8 downlink signaling. Another option is that the eNodeB estimates the channel quality of the four transmit antennas, and selects the best of the two channels. The UE is signaled to the UE. This method requires new DCI format support, which supports more freedom. Uplink antenna selection mode.

Implementation 4:

This embodiment is a flow for performing antenna selection in a scenario in which channel reciprocity cannot be utilized in the TDD mode. In this embodiment, a new DCI format is added, that is, antenna selection indication information of 6 states is added to notify the UE which two The antenna channel quality is the best. The specific antenna selection is shown in flowchart 8. The steps are as follows:

Step 801: Packet the uplink transmit antenna of the UE.

Step 802: Send an uplink reference measurement signal on two antennas in each subframe.

Step 803: Send an uplink reference on two unused antennas on two slots of the next subframe. Measuring signal

Step 804: The eNodeB estimates an uplink channel according to the received uplink reference measurement signal, and sorts the four antenna transmission qualities according to the measured uplink channel result.

Step 805: The eNodeB comprehensively determines, according to the judgment result, which two antennas have higher quality of the transmitting antenna, and notifies the UE to select two antennas of the four antennas as the next subframe transmitting antenna by using the antenna selection indication information;

Step 806: The UE receives the eNodeB notification, and selects a corresponding transmit antenna according to the eNodeB decision. 9 is a schematic diagram of a logical structure of a mobile terminal antenna selection system according to the present invention, including a UE end and an enhanced base station, where the UE includes: a packet unit, a measurement reporting unit, and a selective transmitting unit; and the enhanced base station includes an uplink channel quality estimating unit and a channel notification. unit.

The grouping unit is configured to perform initial grouping on the uplink antenna; the measurement reporting unit is configured to map the uplink reference measurement signal into each subframe in units of antenna packets; and select the transmitting unit to select the antenna group determined according to the grouping unit or the channel notification unit The corresponding antenna is used for transmitting; the uplink channel quality estimating unit is configured to estimate the uplink channel quality of each antenna according to the uplink reference measurement signal reported by the measurement reporting unit, and determine an antenna packet with the best uplink channel quality; the channel notification unit is used for Notifying the UE of the best antenna packet of the uplink channel quality decided by the eNodeB.

The above is only the preferred embodiment of the present invention and is not intended to limit the scope of the present invention.

Claims

Claim

A method for selecting an antenna of a mobile terminal, comprising:

The mobile terminal (UE) reports the uplink reference measurement signal in units of antenna packets in each subframe;

The enhanced base station (eNodeB) estimates the uplink channel quality of each antenna according to the reported uplink reference measurement signal, determines the antenna packet with the best uplink channel quality, and notifies the decision result to the UE;

2. The method according to claim 1, wherein the antenna group is a fixed packet, and the eNodeB estimates an uplink channel quality of each antenna group in units of fixed antenna packets, and determines an uplink to be determined. The antenna group with the best channel quality is notified to the UE.

3. The method of claim 2, wherein

The UE includes two antenna packets, and the uplink reference measurement signals of the two antenna packets are reported to the eNodeB in two consecutive subframes;

The eNodeB separately estimates the uplink channel quality of each antenna group, and after completing the uplink channel quality estimation of the second antenna group, compares the uplink channel quality evaluation results of the two antenna groups, and selects the best uplink channel quality. The antenna packet is notified to the UE.

4. The method of claim 2, wherein

The UE includes two antenna packets, and the uplink reference measurement signals of the two antenna packets are reported to the eNodeB in different time slots of the same subframe;

After receiving the uplink reference measurement signals of the two antenna groups in the same subframe, the eNodeB estimates the uplink channel quality of each antenna group, compares the uplink channel quality evaluation results of the two antenna groups, and selects the uplink channel quality. The best antenna packet is notified to the UE.

5. The method according to claim 1, wherein the antenna group is a non-fixed packet, and the system indicates different combinations of antenna packets by adding new downlink control information (DCI); After receiving the uplink reference measurement signals reported by the antenna groups, the eNodeB separately estimates the uplink channel quality of each antenna, and then sorts the uplink channel quality of each antenna, and selects the antenna with the best uplink channel quality to form a new antenna. The antenna grouping notifies the mobile terminal of the determined new antenna packet by the added downlink control information.

6. The method of claim 5, wherein

The UE includes two antenna packets, and the uplink reference measurement signals of the two antenna packets are reported to the eNodeB in two consecutive subframes.

7. The method of claim 5, wherein

The UE includes two antenna packets, and the uplink reference measurement signals of the two antenna packets are reported to the eNodeB in different time slots of the same subframe, respectively.

8. A mobile terminal antenna selection system, comprising:

Selecting a transmitting unit, located at the UE end, for selecting a corresponding antenna to transmit according to the antenna group determined by the channel notification unit;

The system according to claim 8, wherein the antenna group is a fixed packet, and the uplink channel quality estimating unit estimates an uplink channel quality of each antenna group in units of fixed antenna packets, and passes The channel notification unit notifies the UE of the antenna packet with the best uplink channel quality determined by the eNodeB.

10. The system according to claim 9, wherein the UE includes two antenna packets, and the measurement reporting unit maps the uplink reference measurement signals to two consecutive subframes or the same On different time slots of the subframe, the eNodeB is grouped by two antennas.

11. The system according to claim 8, wherein the antenna group is a non-fixed packet, and the system indicates different combinations of antenna packets by adding new downlink control information; the uplink channel quality estimating unit separately for each antenna The uplink channel quality is estimated, and then the uplink channel quality of each antenna is sorted, and the antenna with the best uplink channel quality is selected to form a new antenna packet, and the channel notification unit notifies the new antenna packet by adding the downlink control information. Give the UE.

12. The system according to claim 11, wherein the UE comprises two antenna groups, and the measurement reporting unit respectively sets the uplink reference measurement signal in two consecutive subframes or the same

A mobile terminal antenna selection method, characterized in that the method is applicable to a scenario in which channel reciprocity is available in a time division duplex system, including:

A mobile terminal antenna selection system, wherein the system is applicable to a scenario in which channel reciprocity is available in a time division duplex system, including: