WO2015117300A1

WO2015117300A1 - Air interface synchronization method and device, and base station

Info

Publication number: WO2015117300A1
Application number: PCT/CN2014/086096
Authority: WO
Inventors: 彭佛才; 戴博; 赵亚军; 毕峰; 夏树强; 韩翠红; 苟伟; 韩晓钢; 胡留军; 张峻峰
Original assignee: 中兴通讯股份有限公司
Priority date: 2014-02-10
Filing date: 2014-09-09
Publication date: 2015-08-13
Also published as: CN104837195A

Abstract

Provided are an air interface synchronization method and device, and a base station. The method comprises: configuring, by a base station, designated uplink and downlink proportions; receiving a physical downlink control channel or an enhanced physical downlink control channel which is transmitted by a source base station, wherein the physical downlink control channel or the enhanced physical downlink control channel is used for indicating an uplink and downlink proportion used after the source base station changes the uplink and downlink proportion; and receiving a reference signal from a subframe of the source base station, which is changed from an uplink subframe to a downlink subframe, and synchronizing with the source base station according to the reference signal.

Description

Air interface synchronization method and device, base station

The present invention relates to a method for synchronizing time (or/and frequency) between base stations in an advanced long-term evolution (hereinafter referred to as LTE-A) mobile communication system, and more particularly to a method and apparatus for air interface synchronization, and a base station. Background technique

According to the third generation mobile communication partner project (hereinafter referred to as 3GPP), the protocol TS36.21 l-b50 (Physical Channels and Modulation), Chapter 4 (Frame Structure), LTE-A (and LTE) contains two frame structures: a type 1 frame structure and a type 2 frame structure. The type 1 frame structure is a frequency division duplex (hereinafter referred to as FDD) frame structure, and the type 2 frame structure is a time division duplex (hereinafter referred to as TDD) frame structure. A system using an FDD frame structure is called an LTE-FDD system, and a system using a TDD frame structure is called a TDD-LTE system (or an LTE-TDD system). In LTE systems (including FDD and TDD), the length of a radio frame is 10 milliseconds. A radio frame is divided into 10 sub-frames, each sub-frame has a time length of one millisecond, and each sub-frame is marked as sub-frame 0, sub-frame 1, sub-frame 2 sub-frame 8, sub-frame in time sequence of sub-frame transmission. 9.

In a TDD-LTE system, some subframes are used to transmit signals to a base station, and a user equipment (hereinafter referred to as UE) receives a signal transmitted by a base station. Such a subframe is called a downlink subframe (labeled as D, or D subframe). . In the TDD-LTE system, some subframes are used to transmit signals to the UE and the base station receives signals transmitted by the UE. Such subframes are called uplink subframes (labeled as U, or U subframes). In the TDD-LTE system, there is also a subframe called a special subframe (labeled as S, or S subframe).

In the TDD-LTE system, the above three seed frames currently have a total of seven combinations (upstream and downlink ratio 0 to uplink and downlink ratio 6), as shown in Table 1 below. When the base station uses a certain uplink-downlink ratio, it will broadcast to the UE through the Type 1 System Information Block (hereinafter referred to as SIB1). It takes a long time (for example, hundreds of milliseconds) for the base station to change from one type of uplink and downlink ratio to another. Up and down with switch point subframe number

Ratio period 0 1 2 3 4 5 6 7 8 9

0 5 ms D s u u U D S U U U

1 5 ms D s u u D D S U U D

2 5 ms D s u D D D s u D D

3 10 ms D s u U U D D D D D

4 10 ms D s u U D D D D D D

5 10 ms D s u D D D D D D D

6 5 ms D s u U U D S U U D

In the LTE-FDD system, synchronization is not required between base stations. Of course, better system performance can be achieved after synchronization between base stations. In the TDD-LTE system, the base stations must be synchronized (whole network synchronization) to avoid uplink-to-downlink interference and downlink-to-uplink interference. In the process of synchronizing between base stations, a base station providing synchronization information (signal, channel) is referred to as a source base station or a source cell, and a base station receiving synchronization information is referred to as a target base station or a target cell. In order to enable synchronization between TDD-LTE base stations, satellite navigation systems (such as Beidou satellite navigation systems, Global Positioning System (GPS), etc.) or the Institute of Electrical and Electronics Engineers (IEEE) 1588V2 technology can be used.

In some cases, there may be no satellite signals (eg, indoors, basements, tunnels, etc.), so satellite navigation systems cannot be used for synchronization between base stations. In some cases, the interface between base stations (referred to as X2 interface) may not provide good transmission quality, or may not provide an interface between the base station and the core network with good transmission quality (referred to as S1 interface), so that IEEE1588V2 technology cannot be used. .

To overcome the above limitations, 3GPP proposes a network interception technology, as shown in Figure 1. In Section 6.4.2 of the 3GPP Technical Report TR36.922-b00, the report gives two methods of network interception: One solution is to configure the target cell to configure one of its own (some) downlinks. The frame is a broadcast multicast single frequency network subframe (hereinafter referred to as an MBSFN subframe) to listen to the synchronization information (signal, channel) of the source cell, so as to be synchronized with the source cell (the scheme is simply referred to as "MBSFN subframe scheme"); One solution is to use the guard interval of a special subframe.

In the MBSFN subframe scheme, the target cell needs to configure one of its own (some) downlink subframes as an MBSFN subframe. However, in the uplink and downlink ratio 0 of the TDD-LTE system, the MBSFN subframe cannot be configured, and the protocol specifies that the subframe 0, 1, 5, and 6 subframes of the TDD cannot be configured with the MBSFN subframe. Therefore, the MBSFN subframe scheme cannot be used in the uplink and downlink ratio 0 of the TDD-LTE system. in In the MBSFN subframe scheme, the MBSFN subframe increases the overhead of the target cell (it cannot serve its own UE on the MBSFN subframe).

According to Section 6.7 of the 3GPP protocol TS36.211-b50, in the MBSFN subframe, the base station needs to transmit a signal at the first one or two symbols. The base station will not be able to receive signals on the same frequency at the transmitted signal, otherwise it will receive its own signal. Signals transmitted by the base station may interfere with neighboring cells. According to recent 3GPP conference progress (eg, 3GPP RAN1#75 conference; see Draft-Minutes-Report-RAN1#75-v010.doc), 3GPP may introduce enhanced interference in future protocols (such as R12) Management and business adaptation (hereafter referred to as elMTA).

In the elMTA technology, the base station may tell a (or a group, a group may include all UEs) through a physical downlink control channel (hereinafter referred to as PDCCH) or an enhanced physical downlink control channel (hereinafter referred to as EPDCCH) to inform the UE of the current radio frame or Which of the uplink and downlink ratios of the next radio frame is. If the base station does not transmit the PDCCH/EPDCCH, the uplink and downlink ratio of the base station is determined by SIB1.

Systematic. For example, if the uplink-downlink ratio is 0 by SIB1, the uplink-downlink ratio given by the PDCCH/EPDCCH may be 1, but not 3. Suppose a certain base station is given an uplink-downlink ratio of 0 by SIB1, and the uplink-downlink ratio given by PDCCH/EPDCCH is 1, then subframe 4 and subframe 8 are changed from U subframe to D subframe.

Therefore, the TDD-LTE system cannot implement network snooping when the uplink-downlink ratio is 0. Some configuration operations may increase system overhead and increase interference of base station transmit signals to neighboring cells.

Summary of the invention

The embodiment of the invention provides a method and device for air interface synchronization, and a base station, so as to enable the TDD-LTE system to detect, reduce system overhead and reduce interference of a base station transmitting signal to a neighboring cell when the uplink-downlink ratio is 0. .

A method for air interface synchronization provided by an embodiment of the present invention includes:

The base station configures the specified uplink and downlink ratio; Receiving, by the base station, a physical downlink control channel or an enhanced physical downlink control channel, where the physical downlink control channel or the enhanced physical downlink control channel is used to indicate the uplink and downlink used by the source base station after converting the uplink and downlink ratios Ratio

The base station receives a reference signal from a subframe in which the source base station changes from an uplink subframe to a downlink subframe, and synchronizes with the source base station according to the reference signal.

Preferably, the foregoing method further has the following features: after receiving, by the base station, the physical downlink control channel or the enhanced physical downlink control channel, the base station further includes:

The base station acquires, according to the physical downlink control channel or the enhanced physical downlink control channel, subframe information that the source base station changes from an uplink subframe to a downlink subframe. Preferably, the foregoing method has the following features: the base station acquires the subframe information that the source base station changes from the uplink sub-frame to the downlink sub-frame, and includes:

The base station obtains subframe information that the source base station changes from the uplink subframe to the downlink subframe by using a blind check or an interface with the source base station.

Preferably, the above method further has the following features: the specified uplink and downlink ratio includes any one of the following:

Up and down ratios 0, 1, 3, 4, 6. In order to solve the above problem, the embodiment of the present invention further provides a method for air interface synchronization, including: configuring, by a base station, a specified uplink and downlink ratio;

a physical downlink control channel or an enhanced physical downlink control channel transmitted on the subframe, where the physical downlink control channel or the enhanced physical downlink control channel is used to indicate a dedicated random access preamble number used by the target cell;

The base station initiates a dedicated random access according to the dedicated random access preamble number, and synchronizes with the source base station according to the received random access response.

Up and down ratios are 0, 1, 3, 4, 6. In order to solve the above problem, the embodiment of the present invention further provides an apparatus for air interface synchronization, which is applied to a base station, where

The configuration module is configured to: configure the specified uplink and downlink ratio;

a receiving module, configured to: receive a physical downlink control channel or an enhanced physical downlink control channel, where the physical downlink control channel or the enhanced physical downlink control channel is used to indicate that the source base station changes the uplink and downlink ratios The upper and lower ratios used;

And a synchronization module, configured to: receive a reference signal from a subframe in which the source base station changes from an uplink subframe to a downlink subframe, and synchronize with the source base station according to the reference signal.

Preferably, the device further has the following features: The device further includes:

And an acquiring module, configured to: acquire, according to the physical downlink control channel or the enhanced physical downlink control channel, the subframe information that the source base station changes from an uplink subframe to a downlink subframe.

Preferably, the foregoing apparatus further has the following features: the acquiring module is configured to obtain, by using a blind detection or by using an interface with the source base station, the subframe that the source base station changes from an uplink subframe to a downlink subframe. informational.

Preferably, the above device also has the following features:

The receiving module is further configured to receive a physical downlink control channel or an enhanced physical downlink control channel that is transmitted by the source base station in a subframe that is changed from an uplink subframe to a downlink subframe after the uplink and downlink ratios are changed, and the physical downlink control channel is received. a channel or an enhanced physical downlink control channel is used to indicate a dedicated random access preamble number used by the target cell;

The synchronization module is further configured to initiate a dedicated random access according to the dedicated random access preamble number, and synchronize to the source cell according to the received random access response.

Preferably, the above device further has the following features: the specified uplink and downlink ratio includes any one of the following:

Up and down ratios 0, 1, 3, 4, 6.

The embodiment of the present invention further provides an apparatus for air interface synchronization, which is applied to a base station, and includes: a configuration module, configured to: configure a specified uplink and downlink ratio;

a receiving module, configured to: the receiving source base station changes in an uplink subframe after converting the uplink and downlink ratio a physical downlink control channel or an enhanced physical downlink control channel transmitted on a subframe of the downlink subframe, where the physical downlink control channel or the enhanced physical downlink control channel is used to indicate a dedicated random access preamble number used by the target cell;

And a synchronization module, configured to: initiate a dedicated random access according to the dedicated random access preamble number, and synchronize with the source base station according to the received random access response.

In order to solve the above problem, an embodiment of the present invention further provides a base station, including the foregoing air interface synchronization device.

In summary, the embodiments of the present invention provide a method and device for air interface synchronization, and a base station, which can enable the TDD-LTE system to implement network interception and reduce system overhead caused by certain configuration operations when the uplink and downlink ratio is 0. The interference of the base station transmit signal to the neighboring cell is reduced (or eliminated). BRIEF abstract

1 is a schematic diagram of network listening of a related art;

2 is a flowchart of a method for air interface synchronization according to an embodiment of the present invention;

Figure 3 is a schematic view of the first embodiment of the present invention;

4 is a schematic diagram of Embodiment 2 of the present invention;

Figure 5 is a schematic view of Embodiment 3 of the present invention;

Figure 6 is a schematic view of Embodiment 4 of the present invention;

Figure 7 is a schematic view of Embodiment 5 of the present invention;

Figure 8 is a schematic view of Embodiment 6 of the present invention;

Figure 9 is a schematic view of Embodiment 7 of the present invention;

FIG. 10 is a schematic diagram of an apparatus for air interface synchronization according to an embodiment of the present invention. Preferred embodiment of the invention

Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. It should be noted that, in the case of no conflict, the features in the embodiments and the embodiments in the present application may be arbitrarily combined with each other.

The technical problem to be solved by the embodiment of the present invention is to enable the TDD-LTE system to be matched in the uplink and downlink ratios of 0. It can realize network listening, reduce system overhead caused by certain configuration operations, and reduce (or eliminate) interference of base station transmit signals to neighboring cells. This technology can also be used by other uplink and downlink ratios of the TDD-LTE system, such as uplink and downlink ratios 1, 3, 4, and 6.

FIG. 2 is a flowchart of a method for air interface synchronization according to an embodiment of the present invention. As shown in FIG. 2, the following steps are included.

Step 11: Configure the target cell and the source cell to be the same or different uplink and downlink ratios.

Step 12: The source cell transmits a PDCCH/EPDCCH to indicate which uplink/down ratio is used by the current radio frame or the next radio frame.

In the foregoing step 12, after the source cell is converted into a new uplink-downlink ratio, the PDCCH/EPDCCH may also be transmitted on the subframe from the U subframe to the D subframe to indicate which dedicated random cell is used by the target cell. Access the preamble number to initiate dedicated random access.

Step 13: The target cell receives and decodes the PDCCH/EPDCCH.

Step 14: The target cell derives, according to the PDCCH/EPDCCH, which uplink/downlink ratio is used by the source cell in the current radio frame or the next radio frame, and learns that the source base station changes from the uplink subframe to the subframe information of the downlink subframe.

In this way, the target cell can know which U subframe has become a D subframe. For example, the ratio of (by SIB1) system broadcast is 0, but the ratio indicated by PDCCH/EPDCCH dynamically is 1, then subframes 5 and 9 become D subframes instead of U subframes. After the target cell knows that it is a D subframe, it can receive the reference signal/data on the subframe.

In the above step 14, the target cell further includes the dedicated random access initiated by the target cell according to the dedicated random access preamble number indicated by the PDCCH/EPDCCH.

Step 15: The source cell transmits a reference signal on one or more subframes on the radio frame that are changed from a U subframe to a D subframe.

In the above step 15, the subframe information for transmitting the reference signal can also be transmitted through an interface between the base stations.

Step 16: The target cell receives the reference signal from the subframe of the source cell or/and receives the random access response from the source cell in the subframe or other subframe.

Step 17: The target cell is based on the received reference signal or/and the random access response described above. Synchronize to the source cell.

Step 18: The process ends.

It can be seen that the method provided by the embodiment of the present invention can enable the TDD-LTE system to implement network sensing or network synchronization according to dedicated random access when the uplink-downlink ratio is 0 and other uplink-downlink ratios, and reduce some configuration operations. Possible system overhead, reducing (or eliminating) interference from base station transmit signals to neighboring cells.

Preferred embodiments of the technical solution of the present invention will be further described in detail below.

Embodiment 1

In this embodiment, the downlink ratio 0, the source d, and the region are changed by the PDCCH/EPDCCH to change the uplink-downlink ratio of 0 to the uplink-downlink ratio 1 (as shown in FIG. 3), and the source cell is in the subframe. The PDCCH/EPDCCH that modifies the uplink-downlink ratio is transmitted (that is, the modified current frame is valid), and the source cell transmits the reference signal in subframe 4 after the uplink-downlink ratio is changed to the uplink-downlink ratio 1 as an example. .

Step 101: Configure the target cell and the source cell to be the same or different uplink and downlink ratios. According to the above configuration, in the embodiment, both the target cell and the source cell are configured to have an uplink-downlink ratio of zero.

Step 102: The source cell transmits a PDCCH/EPDCCH to indicate which uplink/down ratio is used by the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 1 in the current radio frame.

Step 103: The target cell receives and decodes the foregoing PDCCH/EPDCCH.

Step 104: The target cell derives, according to the foregoing PDCCH/EPDCCH, which uplink/down ratio is used by the source cell in the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 1 in the current radio frame.

Step 105: The source cell transmits a reference signal on one or more subframes on the radio frame that are changed from a U subframe to a D subframe. According to the above assumption, in the present embodiment, the source cell transmits a reference signal on subframe 4 of the current radio frame.

Step 106: The target cell receives the reference signal from the foregoing subframe of the source cell. According to the above assumption, in the present embodiment, the target cell is a reference signal for receiving the source cell on the subframe 4 of the current radio frame. Step 107: The target cell synchronizes to the source cell according to the received reference signal.

Step 108: The process ends.

It can be seen that the proposed method in the embodiment of the present invention enables the TDD-LTE system to implement network snooping, reduce system overhead caused by certain configuration operations, and reduce (or eliminate) base station transmit signal pairs when the uplink-downlink ratio is 0. Interference from neighboring cells.

Embodiment 2:

In this embodiment, the downlink ratio 1, the source d, and the region are changed to the uplink-downlink ratio 2 (as shown in FIG. 4) by transmitting the PDCCH/EPDCCH, and the source cell is in the subframe 0. The PDCCH/EPDCCH that modifies the uplink-downlink ratio (that is, the current radio frame is modified after being modified), and the subframe 6 transmits the reference signal after the uplink/downlink ratio is changed to the uplink-downlink ratio 2 is taken as an example.

Step 201: Configure the target cell and the source cell to be the same or different uplink and downlink ratios. According to the above configuration, in the embodiment, both the target cell and the source cell are configured as an uplink-downlink ratio 1.

Step 202: The source cell transmits a PDCCH/EPDCCH to indicate which uplink/downlink ratio is used by the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 2 in the current radio frame.

Step 203: The target cell receives and decodes the foregoing PDCCH/EPDCCH.

Step 204: The target cell derives, according to the foregoing PDCCH/EPDCCH, which uplink/down ratio is used by the source cell in the current radio frame or the next radio frame. According to the above configuration, in the embodiment, the source cell uses the uplink-downlink ratio 2 in the current radio frame.

Step 205: The source cell transmits a reference signal on one or more subframes on the radio frame that are changed from a U subframe to a D subframe. According to the above assumption, in the present embodiment, the source cell transmits a reference signal on subframe 8 of the current radio frame.

Step 206: The target cell receives the reference signal from the foregoing subframe of the source cell. According to the above assumption, in the present embodiment, the target cell is a reference signal for receiving the source cell on the subframe 8 of the current radio frame.

Step 207: The target cell synchronizes to the source cell according to the received reference signal. Step 208: The process ends.

Embodiment 3:

In this embodiment, the downlink ratio 3, the source d, and the region are changed to the uplink-downlink ratio 4 by transmitting the PDCCH/EPDCCH (as shown in FIG. 5), and the source cell is in the subframe 5. The PDCCH/EPDCCH that modifies the uplink-downlink ratio is transmitted (that is, it is valid in the next radio frame after modification), and the source cell transmits the reference signal in subframe 4 after the uplink-downlink ratio is changed to the uplink-downlink ratio 4 as an example. Description.

Step 301: Configure the target cell and the source cell to be the same or different uplink and downlink ratios. According to the above configuration, in the embodiment, both the target cell and the source cell are configured as an uplink-downlink ratio 3.

Step 302: The source cell transmits a PDCCH/EPDCCH to indicate which uplink/down ratio is used by the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 4 in the next radio frame.

Step 303: The target cell receives and decodes the foregoing PDCCH/EPDCCH.

Step 304: The target cell derives, according to the foregoing PDCCH/EPDCCH, which uplink/down ratio is used by the source cell in the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 4 in the next radio frame.

Step 305: The source cell transmits a reference signal on one or more subframes on the radio frame that are changed from a U subframe to a D subframe. According to the above assumption, in the present embodiment, the source cell transmits a reference signal on the subframe 4 of the next radio frame.

Step 306: The target cell receives the reference signal from the foregoing subframe of the source cell. According to the above assumption, in the present embodiment, the target cell is a reference signal for receiving the source cell on the subframe 4 of the next radio frame.

Step 307: The target cell synchronizes to the source cell according to the received reference signal.

Step 308: The process ends. It can be seen that the method provided by the embodiment of the present invention enables the TDD-LTE system to implement network snooping, reduce system overhead caused by certain configuration operations, and reduce (or eliminate) base station transmit signal phase correlation when the uplink-downlink ratio is 3. Interference from neighboring cells.

Embodiment 4:

In this embodiment, the downlink ratio 3, the source d, and the region are changed to the uplink-downlink ratio 5 by transmitting the PDCCH/EPDCCH (as shown in FIG. 6), and the source cell is in the subframe 5. The PDCCH/EPDCCH that modifies the uplink-downlink ratio is transmitted (that is, it is valid in the next radio frame after modification), and the source cell transmits the reference signal in subframe 3 after the uplink-downlink ratio is changed to the uplink-downlink ratio 5 as an example. Description.

Step 401: Configure the target cell and the source cell to be the same or different uplink and downlink ratios. According to the above configuration, in the embodiment, both the target cell and the source cell are configured as an uplink-downlink ratio 3.

Step 402: The source cell transmits a PDCCH/EPDCCH to indicate which uplink/downlink ratio is used by the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 5 in the next radio frame.

Step 403: The target cell receives and decodes the foregoing PDCCH/EPDCCH.

Step 404: The target cell derives, according to the foregoing PDCCH/EPDCCH, which uplink/down ratio is used by the source cell in the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 5 in the next radio frame.

Step 405: The source cell transmits a reference signal on one or more subframes on the radio frame that are changed from a U subframe to a D subframe. According to the above assumption, in the present embodiment, the source cell transmits a reference signal on subframe 3 of the next radio frame.

Step 406: The target cell receives the reference signal from the foregoing subframe of the source cell. According to the above assumption, in the present embodiment, the target cell is a reference signal for receiving the source cell on the subframe 3 of the next radio frame.

Step 407: The target cell synchronizes to the source cell according to the received reference signal.

Step 408: The process ends.

It can be seen that the method provided by the embodiment of the present invention enables the TDD-LTE system to implement network snooping and reduce system overhead caused by certain configuration operations, and reduce (or eliminate) the uplink and downlink ratios of 3. The base station transmits interference of signals to neighboring cells.

Embodiment 5:

In this embodiment, the uplink-downlink ratio of the source cell is 1. The uplink-downlink ratio of the target cell is 0, and the source cell changes its uplink-downlink ratio to the uplink-downlink ratio 2 by transmitting the PDCCH/EPDCCH (as shown in FIG. 7). As shown in the figure, it is assumed that the source cell transmits a PDCCH/EPDCCH that modifies the uplink-downlink ratio in subframe 0 (that is, it is valid in the current radio frame after modification), and the source cell is changed to the uplink-downlink ratio 2 after the uplink and downlink ratio is adjusted. Frame 3 transmits a reference signal as an example to illustrate.

Step 501: Configure the target cell and the source cell to be the same or different uplink and downlink ratios. According to the above assumptions, in this embodiment, the target cell is configured to have an uplink-downlink ratio of 0, but the source cell is configured to be an uplink-downlink ratio 1 (different uplink-downlink ratio).

Step 502: The source cell transmits a PDCCH/EPDCCH to indicate which uplink/down ratio is used by the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 2 in the current radio frame.

Step 503: The target cell receives and decodes the foregoing PDCCH/EPDCCH.

Step 504: The target cell derives, according to the foregoing PDCCH/EPDCCH, which uplink/down ratio is used by the source cell in the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink and downlink ratio 2 in the current radio frame.

Step 505: The source cell transmits a reference signal on one or more subframes on the radio frame that are changed from a U subframe to a D subframe. According to the above assumption, in the present embodiment, the source cell transmits a reference signal on subframe 3 of the current radio frame.

Step 506: The target cell receives the reference signal from the foregoing subframe of the source cell. According to the above assumption, in the present embodiment, the target cell is a reference signal for receiving the source cell on the subframe 3 of the current radio frame.

Step 507: The target cell synchronizes to the source cell according to the received reference signal.

Step 508: The process ends.

It can be seen that the method provided by the embodiment of the present invention enables the TDD-LTE system to implement network snooping, reduce system overhead caused by certain configuration operations, and reduce (or eliminate) base station transmit signal phase correlation when the uplink-downlink ratio is 0. Interference from neighboring cells. Example 6:

In this embodiment, the downlink ratio 0, the source d, and the region are changed to the uplink-downlink ratio 1 (as shown in FIG. 8) by transmitting the PDCCH/EPDCCH, and the source cell is in the subframe 0. Transmitting the PDCCH/EPDCCH that modifies the uplink-downlink ratio (that is, the current radio frame is modified after the modification), and the subframe 4 after the source cell is changed to the uplink-downlink ratio 1 to transmit the target cell to the target cell with a dedicated random connection. The PDCCH/EPDCCH of the incoming preamble is described as an example.

Step 601: Configure the target cell and the source cell to be the same or different uplink and downlink ratios. According to the above configuration, in the embodiment, both the target cell and the source cell are configured to have an uplink-downlink ratio of zero.

Step 602: The source cell transmits a PDCCH/EPDCCH to indicate which uplink/down ratio is used by the current radio frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 1 in the current radio frame.

In the foregoing step 602, after the source cell is converted into a new uplink-downlink ratio, the PDCCH/EPDCCH may also be transmitted on the subframe that is changed from the U subframe to the D subframe to indicate which dedicated target cell is used. The preamble number is randomly accessed to initiate dedicated random access. Based on the previous assumptions, this embodiment has been assumed to be performed using this method.

Step 603: The target cell receives and decodes the foregoing PDCCH/EPDCCH.

Step 604: The target cell derives, according to the foregoing PDCCH/EPDCCH, which uplink/down ratio is used by the source cell in the current wireless frame or the next radio frame. According to the above assumption, in the present embodiment, the source cell uses the uplink-downlink ratio 1 in the current radio frame.

In the above step 604, the target cell further includes dedicated random access according to the PDCCH/EPDCCH. According to the foregoing assumptions, this embodiment has been assumed to be performed by this method.

Step 605: The source cell transmits a reference signal on one or more subframes on the radio frame that are changed from a U subframe to a D subframe. According to the above assumption, in the present embodiment, the source cell transmits a reference signal on subframe 4 of the current radio frame.

In the above step 605, the subframe information for transmitting the reference signal can also be transmitted through an interface between the base stations. In this embodiment, the target cell may know the "subframe information of the transmitted reference signal" by blindly detecting the PDCCH/EPDCCH, and may also know the "subframe information of the transmitted reference signal" through the interface between the base stations. As shown in FIG. 9, if the bit corresponding to a certain radio frame is ", the source cell will change the radio frame to a different ratio. In FIG. 8, it is equivalent to the radio frame Χ=0. Or Χ=512 (Figure 7 takes the period of 1024 radio frames as an example; if the "subframe information of the transmitted reference signal" takes 512 radio frames as the period, then Χ = 0; the radio frame number can be aligned to the LTE system System frame number (SFN)).

Step 606: The target cell receives the reference signal from the subframe of the source cell or/and receives the random access response from the source cell in the subframe or other subframe. According to the above assumption, in the present embodiment, the target cell receives the random access response from the source cell in the above subframe or other subframe.

Step 607: The target cell synchronizes to the source cell according to the received reference signal or/and the random access response. According to the above assumption, in the present embodiment, the target cell synchronizes to the source cell according to the random access response described above.

Step 608: The process ends.

It can be seen that the method provided by the embodiment of the present invention enables the TDD-LTE system to implement network snooping according to dedicated random access and reduce system overhead and reduction caused by certain configuration operations when the uplink and downlink ratio is 0. Eliminating the interference of the base station transmitting signals to neighboring cells.

FIG. 10 is a schematic diagram of an apparatus for air interface synchronization according to an embodiment of the present invention. As shown in FIG. 10, the apparatus in this embodiment may include:

Configure the module, set to configure the specified uplink and downlink ratio;

The receiving module is configured to receive a physical downlink control channel or an enhanced physical downlink control channel that is sent by the source base station, where the physical downlink control channel or the enhanced physical downlink control channel is used to indicate that the source base station uses the uplink and downlink ratios Up and down ratio;

And a synchronization module, configured to receive a reference signal from a subframe in which the source base station is changed from an uplink subframe to a downlink subframe, and synchronize to the source cell according to the reference signal.

In a preferred embodiment, the device may further include:

And an acquiring module, configured to acquire, according to the physical downlink control channel or the enhanced physical downlink control channel, the subframe information that the source base station changes from an uplink subframe to a downlink subframe.

In a preferred embodiment, the acquiring module is performed by blind detection or by using with the source base station. The inter-interface obtains the subframe information that the source base station changes from the uplink subframe to the downlink subframe. In a preferred embodiment, the receiving module may be further configured to receive a physical downlink control channel enhanced by the source base station in the transition, where the physical downlink control channel or the enhanced physical downlink control channel is used to indicate the dedicated use of the target cell. Random access to the leading number;

The synchronization module may be further configured to initiate a dedicated random access according to the dedicated random access preamble number, and synchronize to the source cell according to the received random access response.

The specified uplink and downlink ratio includes any one of the following:

Up and down ratios 0, 1, 3, 4, 6.

An embodiment of the present invention further provides a base station, including the foregoing air interface synchronization device.

One of ordinary skill in the art will appreciate that all or a portion of the above steps may be accomplished by a program instructing the associated hardware, such as a read-only memory, a magnetic disk, or an optical disk. Alternatively, all or part of the steps of the above embodiments may also be implemented using one or more integrated circuits. Correspondingly, each module/unit in the above embodiment may be implemented in the form of hardware or in the form of a software function module. The invention is not limited to any specific form of combination of hardware and software.

The above is only a preferred embodiment of the present invention, and of course, the present invention may be embodied in various other embodiments without departing from the spirit and scope of the invention. Corresponding changes and modifications are intended to be included within the scope of the appended claims.

Industrial applicability

The embodiment of the present invention can enable the TDD-LTE system to implement network listening, reduce system overhead caused by certain configuration operations, and reduce (or eliminate) interference of base station transmit signals to neighboring cells when the uplink and downlink ratio is zero.

Claims

claims

1. An air interface synchronization method, including:

The uplink and downlink ratio specified by the base station configuration;

The base station receives the physical downlink control channel or the enhanced physical downlink control channel transmitted by the source base station. The physical downlink control channel or the enhanced physical downlink control channel is used to instruct the source base station to use uplink and downlink after changing the uplink and downlink ratio. proportion;

The base station receives a reference signal from a subframe in which the source base station changes from an uplink subframe to a downlink subframe, and synchronizes with the source base station based on the reference signal.

2. The method of claim 1, wherein: after the base station receives the physical downlink control channel or the enhanced physical downlink control channel transmitted by the source base station, it further includes:

The base station obtains the subframe information of the source base station from the uplink subframe to the downlink subframe according to the physical downlink control channel or the enhanced physical downlink control channel.

3. The method of claim 2, wherein: the base station obtains the subframe information of the source base station changing from an uplink subframe to a downlink subframe, including:

The base station obtains subframe information when the source base station changes from an uplink subframe to a downlink subframe through blind detection or through an interface with the source base station.

4. The method according to any one of claims 1 to 3, wherein: the specified uplink and downlink ratio includes any of the following:

The uplink and downlink ratios are 0, 1, 3, 4, and 6.

5. An air interface synchronization method, including:

The uplink and downlink ratio specified by the base station configuration;

The physical downlink control channel or enhanced physical downlink control channel transmitted on the subframe is used to indicate the dedicated random access preamble number used by the target cell;

The base station initiates dedicated random access according to the dedicated random access preamble number, according to The received random access response is synchronized with the source base station.

6. The method of claim 5, wherein: the specified uplink and downlink ratio includes any of the following:

The uplink and downlink ratios are 0, 1, 3, 4, and 6.

7. An air interface synchronization device, applied to base stations, including:

Configuration module, its settings are: configure the specified uplink and downlink ratio;

The receiving module is configured to: receive a physical downlink control channel or an enhanced physical downlink control channel transmitted by the source base station. The physical downlink control channel or the enhanced physical downlink control channel is used to instruct the source base station to change the uplink and downlink configuration. The uplink and downlink ratio used; and

A synchronization module, which is configured to: receive a reference signal from a subframe in which the source base station changes from an uplink subframe to a downlink subframe, and synchronize with the source base station according to the reference signal.

8. The device of claim 7, further comprising:

and an acquisition module, which is configured to: acquire the subframe information of the source base station that changes from an uplink subframe to a downlink subframe according to the physical downlink control channel or the enhanced physical downlink control channel.

9. The device of claim 8, wherein:

The acquisition module is configured to: acquire subframe information in which the source base station changes from an uplink subframe to a downlink subframe through blind detection or through an interface with the source base station.

10. The device of claim 7, wherein:

The receiving module is further configured to: receive a physical downlink control channel or an enhanced physical downlink control channel transmitted by the source base station on a subframe that changes from an uplink subframe to a downlink subframe after the uplink and downlink ratio is changed, and the physical downlink control channel is The control channel or enhanced physical downlink control channel is used to indicate the dedicated random access preamble number used by the target cell;

The synchronization module is further configured to: initiate dedicated random access based on the dedicated random access preamble number, and synchronize with the source base station based on the received random access response.

11. The device according to any one of claims 7-10, wherein: the specified uplink and downlink ratio includes any of the following:

The uplink and downlink ratios are 0, 1, 3, 4, and 6.

12. An air interface synchronization device, applied to base stations, including:

The receiving module is configured to: receive the physical downlink control channel or the enhanced physical downlink control channel transmitted by the source base station on the subframe that changes from the uplink subframe to the downlink subframe after the uplink and downlink ratio is changed. The physical downlink control channel Or the enhanced physical downlink control channel is used to indicate a dedicated random access preamble number used by the target cell; and

A synchronization module, which is configured to: initiate dedicated random access according to the dedicated random access preamble number, and synchronize with the source base station according to the received random access response.

13. The device according to claim 12, wherein: the specified uplink and downlink ratio includes any of the following:

The uplink and downlink ratios are 0, 1, 3, 4, and 6.

14. A base station, including the device according to any one of claims 7-13.