TW201642692A - A wireless communication method for activating a secondary carrier - Google Patents

Abstract

A method of activating a secondary cell in a base station of an LTE communication system, wherein the secondary cell is an unlicensed carrier, the method comprising: performing, by the base station, a clear channel assessment on the secondary cell to determine whether the secondary cell is idle; transmitting, by the base station, a preamble signal on the secondary cell when the secondary cell is idle, wherein the preamble signal includes information indicating that the base station activates the secondary cell.

Description

Wireless communication method

The invention relates to the field of communication technologies, in particular to the field of wireless communication technologies.

In the field of wireless communication, in general, the traditional deployment method is that the system works in a licensed band, that is, the entire spectrum resource is reserved for the system. Typically, an LTE communication system works with a licensed band.

However, as wireless services continue to grow, so does the capacity and frequency requirements of wireless communication systems. In this case, the licensed band resources of the LTE system appear to be relatively insufficient. Therefore, one of the recent research hotspots in the LTE field is how to use resources in unlicensed bands to offload high-profile data services. This scheme is called LTE (LTE in Unlicensed Spectrum LTE-U) system.

For example, in a typical scenario, the LTE system uses the frequency band of the WiFi system. That is, the cell of the LTE system and the cell of the WiFi system coexist at least partially in geographical position. In this case, if the LTE system can use the frequency band of WiFi for certain high-load moments, the service is divided. Streaming, obviously, can greatly improve the performance of the system, thus effectively coping with high-load application scenarios.

Obviously, in the case where LTE and WiFi systems coexist, it is the most direct choice to use the licensed spectrum of the LTE system to assist the access of the unlicensed spectrum of the WiFi system. Therefore, regarding the authorized access (Licensed-Assisted Access for LAA) ) has become a hot spot in the field of mobile communications.

The LAA technology can be used to maximize the carrier aggregation and carrier spectrum aggregation (CAR) scheduling of the licensed spectrum and the unlicensed spectrum. However, in order to be compatible with the system of unlicensed spectrum, it is necessary to introduce some new mechanisms. One of the first problems is how to implement the pre-transmission interception (LBT) of the unlicensed spectrum in the LTE-LAA system.

For example, a certain unlicensed spectrum is aggregated as a secondary cell (Scell) of the LTE system and a certain authorized spectrum as a primary cell (Pcell). Then, before the Pcell attempts to start the Scell, the base station must determine that the Scell is not occupied by other systems. Therefore, the base station needs to perform Clear Channel Assessment (CCA) on the Scell to determine that the channel is idle, and then perform the operation of starting the Scell. However, when using the Load Load Equipment (LBT) mode, the Pcell will only attempt to start the Scell when there is a load to be sent. That is, when the base station performs CCA is uncertain, and at this time, Scell Whether it is idle or not, the base station cannot determine in advance. In this case, how does the base station notify Its user equipment (User Equipment referred to as UE), a certain Scell has been started / started to become a problem to be solved.

In the current discussion, there are two proposals for this issue. First, by letting the UE blindly decode the PDCHH or the Cell Reference Signal (CRS) on the Scell, if the PDCCH or the CRS can be successfully decoded, the base station has started the Scell, and the method does not need to introduce a new letter. However, it requires the UE to perform additional blind decoding operations on the Scell, which means great power consumption, and considering the use of the unlicensed spectrum is very sparse, such power consumption causes a great waste of UE standby time. Another method is to express the start of the Scell by sending indication signaling on the grant spectrum, ie, the Pcell. This has the advantage of saving power, however, it is required to introduce a new signaling interaction, and more importantly, because the UE does not know the base station. When the indication signaling is sent, the UE must buffer each sub-frame data on the Scell, so that after receiving the Pcell indication signaling, the data transmission on the Scell can be correctly processed. Obviously, the UE is The cache also creates a huge waste and is not an ideal solution.

Therefore, the object of the present invention is to find a new method for starting an Scell; this method needs to enable the base station to effectively notify the UE that a certain Scell has been activated in the case of the LAA, and to avoid causing the power to the UE as much as possible. And the waste of caching.

In order to solve the above problems in the prior art, the present invention proposes a new one. The method of starting Scell. By letting the base station add the information indicating the start when transmitting the preamble of the Scell, it is ensured that the UE can know that the Scell has been started in time and accurately.

Specifically, according to the first aspect of the present invention, a method for starting a secondary cell in a base station of an LTE communication system is proposed, wherein the secondary cell is an unlicensed spectrum, and the method includes: the base station is in the auxiliary Performing an idle channel evaluation on the cell to determine whether the secondary cell is idle; when the secondary cell is idle, the base station sends a preamble signal on the secondary cell, where the preamble signal includes the indication that the base station is activated. The information of the secondary cell.

Preferably, after the second step, the base station further sends a first message on the primary cell, where the first message is used to notify a first quantity of user equipment, and the base station Communicating with the first number of user equipments on the secondary cell, wherein the first number of user equipments are user equipments that are scheduled by the base station to communicate on the cell.

More preferably, after the foregoing step, the base station sends a second message on the primary cell, where the second message is used to notify the first number of user equipments, and the base station will not Communicating with the first number of user devices on the secondary cell.

Preferably, the information indicating that the base station starts the secondary cell comprises an orthogonal sequence related to a cell identifier of the base station.

More preferably, the orthogonal sequence related to the cell identifier of the base station includes a primary synchronization signal sequence and/or a secondary synchronization signal of the base station. sequence.

According to a second aspect of the present invention, a method for initiating a secondary cell in a user equipment of an LTE communication system is provided, wherein the secondary cell is an unlicensed spectrum, and the method includes: the user equipment receiving the base station a preamble signal sent by the secondary cell, where the preamble signal includes information indicating that the base station starts the secondary cell.

Preferably, after the step, the user equipment receives the first message sent by the base station on the primary cell, where the first message is used to notify the user equipment, and the base station will Communicating with the user equipment on the secondary cell.

More preferably, after the step, the user equipment receives the second message sent by the base station on the primary cell, where the second message is used to notify the user equipment, and the base station will No longer communicate with the user equipment on the secondary cell.

According to the third party of the present invention, a device for starting a secondary cell in a base station of an LTE communication system is proposed, wherein the secondary cell is an unlicensed spectrum, and the device includes: an evaluation module, where the base station is used Performing an idle channel evaluation on the secondary cell to determine whether the secondary cell is idle; a preamble sending module, configured to send a preamble signal on the secondary cell when the secondary cell is idle, where the The preamble signal includes information indicating that the base station starts the secondary cell.

Preferably, the method further includes: a first sending module, configured to send, by the base station, a first message on a primary cell, where the first message is used to notify a first quantity of user equipment, where the base station is to be The secondary cell and the first A quantity of user equipments communicate, wherein the first number of user equipments are user equipments that are scheduled by the base station to communicate on the cell.

More preferably, the second sending module is configured to send, by the base station, the second message on the primary cell, where the second message is used to notify the first quantity of user equipment, The base station will no longer communicate with the first number of user equipments on the secondary cell.

According to a fourth aspect of the present invention, a device for starting a secondary cell in a user equipment of an LTE communication system is provided, wherein the secondary cell is an unlicensed spectrum, and the method includes: a preamble receiving module, The user equipment receives the preamble signal sent by the base station on the secondary cell, where the preamble signal includes information indicating that the base station starts the secondary cell.

Preferably, the first receiving module is configured to receive, by the user equipment, the first message sent by the base station on the primary cell, where the first message is used to notify the user equipment, The base station will communicate with the user equipment on the secondary cell.

More preferably, the second receiving module is configured to receive, by the user equipment, a second message sent by the base station on the primary cell, where the second message is used to notify the user equipment, The base station will no longer communicate with the user equipment on the secondary cell.

In the present invention, by using the existing preamble signal to indicate the information to be activated, it is ensured that the UE can save power by eliminating the need for additional blind decoding operations; by transmitting the preamble signal before transmitting the data, it is ensured. The UE only starts to buffer the sub-frame on the Scell after determining that the Scell has been started, thereby saving the cache space; and in the preferred scheme, only the part of the UE to be scheduled can be notified, thereby reducing the waste of the overall performance of the system. The object of the invention is achieved.

30‧‧‧ Equipment

40‧‧‧ Equipment

3001‧‧‧Evaluation Module

3002‧‧‧Preamble Sending Module

4001‧‧‧Preceding Receiver Module

Other features, objects, and advantages of the invention will be apparent from the description of the accompanying drawings.

1 is a flow chart showing a method of starting an Scell in a base station of an LTE communication system according to the present invention; FIG. 2 is a flowchart showing a method of starting an Scell in a user equipment of an LTE communication system according to the present invention. FIG. 3 is a block diagram showing an apparatus for starting an Scell in a base station of an LTE communication system according to the present invention; FIG. 4 is a diagram showing a device for starting a Scell in a user equipment of an LTE communication system according to the present invention; Block diagram.

Wherein, the same or similar reference numerals indicate the same or similar step features or devices/modules.

In the detailed description of the preferred embodiments that follow, reference is made to the accompanying drawings that form a part of the invention. The accompanying drawings illustrate, by way of example, specific embodiments The exemplary embodiments are not intended to be exhaustive of all embodiments in accordance with the invention. Understandably, without deviating from this Other embodiments may be utilized, and structural or logical modifications may be made without departing from the scope of the invention. Therefore, the following detailed description is not to be construed as limiting the scope of the invention.

First, according to the application scenario of the present invention, there is an area covered by an LTE communication system, including at least one base station and the UE, and an authorization spectrum between the two, that is, Pcell. In addition, there are other unlicensed spectrums in the area, wherein the unlicensed spectrum can also be used by other LTE or WiFi communication systems.

Since the base station operates in the LBE mode, the base station performs CCA or ECCA (Extended CCA) operation on the unlicensed spectrum only when the base station considers it necessary to use the unlicensed spectrum as the Scell for transmission. At this moment, the unlicensed spectrum is idle. However, considering that the time taken for CCA/ECCA operation is extremely short (the shortest time is about 20 microseconds), it is much smaller than the time of one LTE sub-frame. Therefore, the CCA/ECCA operation of the base station may occur in a sub-frame of the Scell, which means that even if the base station confirms that the Scell is idle in the current sub-frame, the complete data transmission can only be sent in the next sub-box. . The current sub-frame is not yet finished, so the base station must occupy the rest of the current sub-frame in some way. Otherwise, if other systems perform the CCA/ECCA operation in the remaining time of the current sub-frame, the base station will also judge the Scell is idle and available, which is bound to cause conflicts in the next sub-frame. In order to solve the problem that the base station occupies the unlicensed spectrum in the current sub-frame, the industry has proposed a scheme: after confirming that the Scell is available, the base station sends the preamble signal in the remaining time of the current sub-frame, so that After other devices perform CCA/ECCA operations, they can be perceived that the carrier is occupied by a certain system. It is further proposed that the preamble signal can also be used for the receiving end to adjust the automatic gain control (AGC). For this purpose, the UE can blindly decode the preamble signal on the Scell.

Based on the foregoing solution, the present invention further provides that information about the Scell that the base station has started may be added to the preamble signal, so that when the UE blindly decodes the preamble signal, it can be known that the base station will start at the next sub-frame in the Scell. Data transfer is performed. Thereby, the UE can accurately know when to start buffering the data on the Scell without buffering each sub-frame material on the Scell. At the same time, the blind decoding operation is performed by the UE, and thus no new operation is introduced to cause power loss. The object of the invention is thus achieved.

Based on this, according to an embodiment of the present invention, a method for starting an Scell in a base station of an LTE communication system is proposed. Specifically, the base station first performs a CCA/ECCA operation on the Scell to determine whether the Scell is idle.

In the second step, if the result is that the Scell is idle, the base station sends a preamble signal through the Scell, where the preamble signal includes information indicating that the Scell is started.

Preferably, the indication may be performed using an orthogonal sequence related to the cell identifier (Cell ID) of the base station. Typically, the base station's Primary Synchronization Signal (PSS) sequence and/or secondary synchronization signal (Secondary Synchronization) may be used. Signal is referred to as SSS) sequence to indicate.

In addition, after the foregoing second step, the base station may also send a first message on the Pcell for notifying the UEs scheduled to be on the Scell, and the base station will communicate with them on the Scell. The advantage of this is that only a part of the UEs are scheduled to be sent to the Scell, so that all the UEs need not be cached on the Scell, and the Pcell can directly indicate which UE needs to cache the Scell data. Thereby saving the cache space of other UEs.

Further, when the base station is about to start the Scell, the base station may also send a second message on the Pcell for notifying the UEs scheduled to be on the Scell, and the base station will no longer communicate with them on the Scell. In this way, the UEs know that starting from the next sub-frame, it is no longer necessary to cache the data on the Scell, thereby releasing the buffer space.

1 is a flowchart of activating a Scell according to the foregoing embodiment, including: S11. The base station performs an idle channel evaluation on the secondary cell to determine whether the secondary cell is idle; S12. When the secondary cell is idle The base station sends a preamble signal on the secondary cell, where the preamble signal includes information indicating that the base station starts the secondary cell.

Correspondingly, according to another embodiment of the present invention, a method for starting an Scell in a UE of an LTE communication system is proposed. Specifically, the UE receives the preamble signal sent by the base station on the Scell, and the preamble signal includes information indicating that the base station starts the Scell.

Further, the UE receives the first message sent by the base station on the Pcell, where the first message is used to notify the UE, and the base station will communicate with the UE at the Scell.

Preferably, the UE may receive the second message sent by the base station on the Pcell, where the second message is used to notify the UE that the base station will no longer communicate with the UE in the Scell.

2 is a flowchart of activating a Scell according to the foregoing embodiment, including: S21. The user equipment receives a preamble signal sent by a base station on the secondary cell, where the preamble signal includes the base station The information of the secondary cell is started.

Hereinafter, the apparatus corresponding to the above method provided by the present invention will be described with reference to the accompanying drawings, and in view of the corresponding relationship between the unit/device features and the step features in the above method, it will be simplified.

FIG. 3 shows an apparatus 30 for starting an Scell in a base station of an LTE communication system according to the present invention, the apparatus comprising: an evaluation module 3001, configured to perform an idle channel evaluation on the secondary cell by the base station, Determining whether the secondary cell is idle or not; the preamble transmitting module 3002, configured to: when the secondary cell is idle, the base station sends a preamble signal on the secondary cell, where the preamble signal includes the indication that the base station starts Information of the secondary cell.

FIG. 4 shows a device 40 for starting an Scell in a UE of an LTE communication system according to the present invention, the device comprising: a preamble receiving module 4001, configured to receive a base station by the user equipment a preamble signal sent by the secondary cell, where the preamble signal includes information indicating that the base station starts the secondary cell.

The embodiments of the present invention have been described above, but the present invention is not limited to the specific systems, equipment, and specific protocols, and various modifications and changes can be made by those skilled in the art within the scope of the appended claims.

Other variations to the disclosed embodiments can be understood and effected by those of ordinary skill in the art. The word "comprising" does not exclude other elements and steps, and the word "a" does not exclude the plural. In the present invention, "first" and "second" refer only to names, and do not represent order relationships. In the practical application of the invention, a part may perform the functions of a plurality of technical features cited in the scope of the patent application. Any reference signs in the claims should not be construed as limiting the scope.

Claims (14)

A method for starting a secondary cell in a base station of an LTE communication system, wherein the secondary cell is an unlicensed spectrum, the method includes: a. the base station performs an idle channel assessment on the secondary cell to determine whether the secondary cell is idle; b When the secondary cell is idle, the base station sends a preamble signal on the secondary cell, where the preamble signal includes information indicating that the base station starts the secondary cell. The method of claim 1, wherein after the step b, the base station sends a first message on the primary cell, wherein the first message is used to notify the first number of users. The device, the base station, communicates with the first number of user equipments on the secondary cell, wherein the first number of user equipments are user equipments scheduled by the base station to communicate on the community. The method of claim 2, wherein after the step c, the d. the base station sends a second message on the primary cell, wherein the second message is used to notify the first quantity. The user equipment, the base station will no longer communicate with the first number of user equipments on the secondary cell. The method of claim 1, wherein the information indicating that the base station activates the secondary cell comprises an orthogonal sequence related to a cell identifier of the base station. According to the method of claim 4, wherein the The orthogonal sequence associated with the cell identity of the base station includes a primary synchronization signal sequence and/or a secondary synchronization signal sequence of the base station. A method for starting a secondary cell in a user equipment of an LTE communication system, wherein the secondary cell is an unlicensed spectrum, the method includes: A. the user equipment receives a preamble signal sent by the base station on the secondary cell, where The preamble signal includes information indicating that the base station starts the secondary cell. The method of claim 6, wherein after the step A, the user equipment receives the first message sent by the base station on the primary cell, wherein the first message is used for notification. The user equipment, the base station will communicate with the user equipment on the secondary cell. The method of claim 7, wherein after the step B, the user equipment receives the second message sent by the base station on the primary cell, wherein the second message is used for notification. The user equipment, the base station will no longer communicate with the user equipment on the secondary cell. A device for starting a secondary cell in a base station of an LTE communication system, wherein the secondary cell is an unlicensed spectrum, the device includes: an evaluation module, configured to perform idle channel estimation on the secondary cell, and determine the secondary cell If the secondary cell is idle, the base station sends a preamble signal on the secondary cell, where the preamble signal includes information indicating that the base station starts the secondary cell. The device of claim 9, further comprising: a first sending module, configured to send, by the base station, a first message on the primary cell, where the first message is used to notify the first number of user devices The base station will communicate with the first number of user equipments on the secondary cell, wherein the first number of user equipments are user equipments scheduled by the base station to communicate on the community. The device of claim 10, further comprising: a second sending module, configured to send, by the base station, a second message on the primary cell, where the second message is used to notify the first quantity of the use Device, the base station will no longer communicate with the first number of user equipments on the secondary cell. A device for activating a secondary cell in a user equipment of an LTE communication system, wherein the secondary cell is an unlicensed spectrum, the method comprising: a preamble receiving module, configured to receive, by the user equipment, a base station to send on the secondary cell a preamble signal, where the preamble signal includes information indicating that the base station starts the secondary cell. The device of claim 12, further comprising: a first receiving module, configured to receive, by the user equipment, a first message sent by the base station on the primary cell, where the first message is used to notify the The user equipment, the base station will communicate with the user equipment on the secondary cell. According to the equipment described in claim 13 of the patent application, The second receiving module is configured to receive, by the user equipment, a second message sent by the base station on the primary cell, where the second message is used to notify the user equipment, where the base station is no longer in the secondary cell Communicate with the user device.