Patent Description:
In current system, uplink channel is detected relying on sounding symbol. eNB can acquire uplink channel information by the way that terminal equipment sends sounding symbol at the last symbol of SRS subframe, so as to schedule and measure resource transmitted through uplink, including measurement of RI (Rank Indication)/PMI (Precoding Matrix Indicator)/CQI (Channel Quality Indication), etc. SRS in LTE (Long Term Evolution) system is sent periodically, that is, terminal equipment will send sounding symbol continuously based on certain periodicity till entering the state of no data transmission. Parameters of periodic SRS are all configured through high-layer, including CS (Cycle Shift), bandwidth, frequency hopping parameter, periodicity, subframe sending position, etc. of SRS.

Owing to long scheduling periodicity and low scheduling efficiency, periodic SRS often occupies much more physical resources. Especially in LTE-A (Long Term Evolution Advanced) system, UE (User Apparatus) often requires sending SRS of multiple antennas at the same time, thus resulting in more resource consumption. To improve SRS resource utilization rate and reduce consumption of SRS resource, aperiodic SRS transmission is introduced in LTE-A system. Differing from periodic SRS, aperiodic SRS is dynamically activated by eNB. Once activating aperiodic SRS, terminal equipment will only send one-off sounding symbol, but not the periodic sounding symbol. eNB can acquire the required channel information more flexibly upon aperiodic sounding and it can reduce consumption of physical resource of SRS if closing or reducing transmission of periodic SRS when conditions permit.

Both periodic SRS and aperiodic SRS are transmitted above dedicated SRS subframe of cell, so it is necessary to solve the problem on how to schedule aperiodic SRS resource to provide adequate physical resource and ensure there is no resource conflict occurring to periodic SRS. Meanwhile, terminal equipment can transmit SRS in a more flexible mode after receiving parameter configuration and activation signalling of eNB. In present technologies, dedicated DCI format (Downlink Control Indicator format) for SRS is introduced in PDCCH (Physical Downlink Control Channel) to configure parameter of aperiodic SRS and share the same length with other uplink formats (such as format0) for multiplexing, thus realizing dynamic resource configuration. Both frequency-domain configuration and time-domain subframe configuration of aperiodic SRS are included in DCI format. Terminal equipment can conduct aperiodic SRS transmission in time frequency resource that controls signalling indicator after receiving control signalling sent by eNB. Another solution is to activate aperiodic SRS only with <NUM> bit signalling in UL grant or DL grant, and transmission parameters of both time-domain and frequency-domain are indicated through high-layer signalling.

In the above meeting, proposals of Aperiodic SRS Transmission in LTE-A are also provided by CATT, Potevio, referring to "R1-<NUM>-A Aperiodic SRS Transmission in LTE-A".

Also in the above meeting, proposals of aperiodic dynamic SRS are provided by Qualcomm Incorporated, referring to "R1-<NUM> Further details on aperiodic dynamic SRS".

During implementation of the embodiments of the present invention, the applicant finds that the following problems exist in the available technology at least:
Configuration of aperiodic SRS by introducing dedicated DCI format of SRS in present technology will greatly increase resource consumption of PDCCH, even waste PDCCH resource to certain extent due to less configuration bit. There will be great resource consumption if many users are activated, thus making PDCCH unaffordable.

The embodiments of the present invention provide a method for transmitting an aperiodic SRS (Sounding Reference Symbol), a terminal equipment and an evolved Node B, as defined in the accompanying claims.

Compared with available technology, the embodiments of the present invention have the following advantages: the present invention can reduce signalling overhead relying on high-layer semi-static configuration of time-domain resources of the aperiodic SRS. On one hand, a flexible aperiodic SRS time-domain transmission is allowed for the terminal equipment which can send the aperiodic SRS in multiple subframes and which is featured by low sounding delay and great sounding bandwidth. On the other hand, a flexible timing mode is also permitted for a terminal equipment which brings little restriction to scheduling.

In an LTE-A system, a periodic SRS (Sounding Reference Symbol) requires occupying much more physical resources due to introduction of multiple antenna transmission. To improve SRS resource utilization rate and reduce consumption of SRS resource, an aperiodic SRS transmission is introduced in the LTE-A system to activate one-off sounding through dynamic scheduling.

It is necessary to solve a problem of how to conduct time-domain resource scheduling of an aperiodic SRS and send the aperiodic SRS by a terminal equipment after receiving signalling from an eNB in a right way.

The embodiments of the present invention provide a transmission method for an aperiodic SRS. The eNB configures time-domain parameters of the aperiodic SRS through high-layer signalling or PDCCH signalling, and a terminal equipment conducts SRS transmission based on the configuration, which can reasonably and effectively schedule and transmit time-domain resources of the aperiodic SRS.

To solve the problem existing in current technology, embodiments of the present invention provide a transmission method for the aperiodic SRS in consideration of compatible LTE system.

The embodiments of the present invention provide a transmission method for the aperiodic SRS, including: the eNB informing a terminal equipment of parameter configuration of the aperiodic SRS through high-layer signalling or PDCCH signalling, and the terminal equipment conducting flexible aperiodic SRS transmission based on the parameter configuration.

Implementation of a UE side and an eNB side as well as cooperation of both will be described. However, it does not mean the two must be implemented in cooperation. In fact, when the UE and the eNB are implemented separately, the problems existing in the UE and eNB sides are solved. Application of the two in combination will acquire better technical effects.

As shown in <FIG>, a flow diagram of transmission method for an aperiodic SRS is provided in embodiments of the present invention, and the method comprises the following steps S101 and S102.

Step <NUM>: a terminal equipment receives time-domain configuration parameters of an aperiodic SRS sent by an eNB through high-layer signalling or PDCCH signalling.

Herein, configuration parameters of aperiodic SRS specifically comprise:.

In this condition, it is required to preset a specific time-domain resource configuration periodicity for both the terminal equipment and the eNB. Based on this, the time-domain resource configuration periodicity used by the terminal equipment can be informed according to default indication information or other parameter values that can represent the hidden indication information.

Condition II, dominant indication information, viz. the configuration information clearly indicating a value of the time-domain resource configuration periodicity used by the terminal equipment.

Such indication information requires occupying corresponding resource spaces. Thus, it can be predetermined that the terminal equipment acquires corresponding indication information in the corresponding resource spaces.

Condition III, configuration information associated with subframe configuration information.

A clear correspondence exists in such associated information so as to facilitate the terminal equipment to acquire corresponding configuration information.

(<NUM>) Subframe configuration information of the aperiodic SRS, which can be divided into the following specifically.

Condition I, continuous indicator, viz. clearly pointing out starting information and length information of subframe resources used by the terminal equipment.

The terminal equipment can clearly acquire which subframe resources are ones configured for itself through this indication.

Condition II, discrete indicator, viz. the information indicating whether one or more subframes are used by the terminal equipment for transmitting the aperiodic SRS.

Thus, it can indicate whether one or more subframes are the subframe sources configured for the terminal equipment in designated resource through clear indication information.

Condition III, configuration information associated with configuration information of time-domain resource configuration periodicity.

Step <NUM>: when the terminal equipment receives aperiodic SRS activation signalling sent by the eNB, the terminal equipment selects corresponding time-domain resources to send the aperiodic SRS to the eNB in accordance with the time-domain configuration parameters of the aperiodic SRS.

Transmission strategy can be divided into the following during implementation:.

The abovementioned flow is one transmission method for aperiodic SRS provided by the embodiments of the invention at a terminal equipment side. Accordingly, the embodiments of the invention also provide an implementation flow at an eNB side.

As shown in <FIG>, a flow diagram of transmission method for aperiodic SRS at the eNB side is provided in embodiments of the present invention, and the method comprises the following steps.

Step <NUM>: the eNB sends time-domain configuration parameters of the aperiodic SRS to the terminal equipment through high-layer signalling or PDCCH signalling.

Herein, please refer to the description in Step <NUM> for time-domain configuration parameters of the aperiodic SRS, and it will not be described repeately.

Step <NUM>: in case that the eNB sends aperiodic SRS activation signalling to the terminal equipment, the eNB will receive the aperiodic SRS sent by terminal equipment through time-domain resources selected according to the time-domain configuration parameters of the aperiodic SRS.

Corresponding to the two transmission strategies in the Step <NUM>, specific flow of the step is as follows:.

It can be seen from the embodiments that compared with present technology, embodiments of the present invention at least have the following advantages.

The application of the technical solution of the embodiments of the present invention can reduce signalling overhead through high-level semi-static configuration of time-domain resources of the aperiodic SRS. On one hand, flexible aperiodic SRS time-domain transmission is allowed for the terminal equipment which can send the aperiodic SRS in multiple subframes, which is featured by low sounding delay and great sounding bandwidth. On the other hand, a flexible timing mode is also permitted for the terminal equipment which brings little restriction to scheduling.

The technical solution provided by the embodiments of the present invention will be explained in combination with specific implementation scene.

An implementation flow at the terminal equipment side shall be taken as the example for easy description as below, so is at the eNB side.

As shown in <FIG>, a flow diagram of transmission method for aperiodic SRS under specific application scene is provided by embodiments of the present invention, and the method comprises the following steps:
Step <NUM>, a terminal equipment receives high-layer signalling or PDCCH signalling indicators sent by an eNB to acquire time-domain configuration parameters of aperiodic SRS, which at least comprises:.

For example, both the terminal equipment and the eNB are set to take <NUM> as time-domain resource configuration periodicity of the aperiodic SRS.

Mode II, dominant indication mode, independently indicating the configuration periodicity of time-domain resource for transmitting aperiodic SAR with several bits.

For example, configuration periodicity of time-domain resource used for transmitting aperiodic SRS is indicated by indication information carried in <NUM> bit in high-layer signalling or PDCCH signalling to be <NUM> or <NUM>.

Mode III, indication mode similar to that of periodic SRS to indicate jointly with subframe configuration.

Explanation through two specific embodiments is made as below:.

Embodiment I: every user is allowed to configure only one aperiodic SRS subframe and two different time-domain periodicitys. Refer to Table <NUM> for specific configuration indication:.

Embodiment II: every user is allowed to configure two aperiodic SRS subframes and a time-domain periodicitys. Refer to Table <NUM> for specific configuration indication:.

(<NUM>) Subframe configuration information of aperiodic SRS, which can be divided into three indication modes:
Mode I, continuous indication mode, independently indicating initial position index and continuous length (viz. the continuous subframe number) of subframe resource.

For example, indicate <NUM> possible initial subframes position with <NUM> bits in high-layer signalling or PDCCH signalling, then indicate <NUM>-<NUM> possible continuous subframes number with <NUM> bits.

Mode II, discrete indication mode, indicating whether each subframe can be used for transmitting aperiodic SRS of user in bitmap mode;.

For example, indicate whether the <NUM> subframes can be used for transmitting aperiodic SRS of the user respectively with <NUM> bits in high-layer signalling or PDCCH signalling. If the subframe is used for transmitting aperiodic SRS, the corresponding bit is <NUM>, otherwise, it is <NUM>.

For example, <NUM> represents that the <NUM>st, <NUM>th and <NUM>th subframes can be used for transmitting aperiodic SRS.

Mode III, the indication mode similar to that of periodic SRS for indicating jointly with configuration periodicity of time-domain resource.

Specific embodiments are similar to those in the Table <NUM> and Table <NUM>, and will not be described hereby.

Step <NUM>, terminal equipment sends aperiodic SRS in corresponding time-domain resources when receiving aperiodic SRS activation signalling sent by eNB.

It can be treated in the following two modes in specific application scene:.

It shall be further noted that technical solution provided by embodiments of the present invention is extensively applied. It can be used for uplink transmission with any antenna quantity and array (such as linear array, polarization array) in any duplexing system (TDD (Time Division Duplex) or FDD (Frequency Division Duplex) system), and in any sending mode (such as SU-MIMO (Single Users-MIMO), MIMO (Multiple Input Multiple Output), MU-MIMO (MultipleUsers-MIMO), CoMP (Coordinated multi-point transmission/reception), etc..

Based on the same inventive concept, embodiments of the present invention also provide a terminal equipment and an eNB. Since the principle of these apparatuss to solve problem is similar to the transmission method for aperiodic SRS (Sounding Reference Symbol), these sets of apparatus shall be implemented with reference to the implementation of the method, which will not be described again hereby.

The embodiments of the present invention also provide a terminal equipment, structural diagram of which is shown in <FIG>, further including:
Reception module <NUM>, which is used to receive time-domain configuration parameters of aperiodic SRS sent by eNB through high-layer signalling or PDCCH signalling, as well as aperiodic SRS activation signalling sent by the eNB.

Specifically, the time-domain configuration parameter of the aperiodic SRS received by the reception module <NUM> includes configuration information of time-domain resource configuration periodicity and subframe configuration information of aperiodic SRS.

Herein, configuration information of the time-domain resource configuration periodicity of aperiodic SRS refers to:.

The subframe configuration information of the aperiodic SRS refers to:.

Sending module <NUM>, which is used to select corresponding time-domain resources and send aperiodic SRS to the eNB in accordance with the time-domain configuration parameters of aperiodic SRS received by the reception module <NUM> when the reception module <NUM> receives aperiodic SRS activation signalling sent by the eNB. The module will be treated in following two conditions under specific application scene:.

Accordingly, embodiments of the present invention also provide an eNB, whose the structural diagram is shown in <FIG>, including:
Sending module <NUM>, which is used to send time-domain configuration parameters of the aperiodic SRS to the terminal equipment through high-layer signalling or PDCCH signalling, and send aperiodic SRS activation signalling to terminal equipment.

Herein, the time-domain configuration parameters of aperiodic SRS are similar to the aforementioned one, and it will not be described repeatedly.

Reception module <NUM>, which is used to receive the aperiodic SRS sent by the terminal equipment through time-domain resources selected in accordance with the time-domain configuration parameters of the aperiodic SRS after sending module <NUM> sends the aperiodic SRS activation signalling to the terminal equipment.

Corresponding to invention mode of the terminal equipment, receiving mode for this module is divided into the following conditions:.

Through the description of implementation mode aforethe, technician of the field can clearly understand that embodiments of the present invention can be realized through hardware or software and necessary universal hardware platform. Accordingly, technical solution in embodiments of the present invention can be embodied in form of software product which can be stored in a non-volatile memory medium (CD-ROM, USB flash disc, Mobile HD, etc.), including several instructions to enable one computer apparatus (personal computer, server or network apparatus, etc.) to implement the method mentioned in all implementation scenes in embodiments of the present invention.

Technician of the field can understand that attached figure is just a schematic diagram of preferred implementation scene; module or flow in the attached figure is not necessary to implement embodiments of the present invention.

Technician of the field can understand that modules in device in implementation scene can be distributed in devices of implementation scene according to its description, and also can be distributed in one or many devices that are different from the implementation scene. Modules in the implementation scene can be combined as one module, or further dismantled into several sub-modules.

Claim 1:
A method for transmitting aperiodic Sounding Reference Symbol, SRS, comprising:
receiving (S101), by a terminal equipment, time-domain configuration parameters of the aperiodic SRS sent by an Evolved Node B, eNB, through high-layer signalling or Physical Downlink Control Channel, PDCCH, signalling;
characterized in that,
the method further comprises:
receiving aperiodic SRS activation signaling sent by the eNB after the eNB sends the time-domain configuration parameters;
directly sending, in accordance with the time-domain configuration parameters of the aperiodic SRS, the aperiodic SRS in all configuration subframes within one time-domain resource configuration periodicity after a number of subframes subsequent to receiving aperiodic SRS activation signaling, wherein the all configuration subframes within one time-domain resource configuration periodicity are determined according to the time-domain configuration parameters.