CN108737056B

CN108737056B - TA (timing advance) determination method under carrier aggregation of LTE-A (Long term evolution-advanced) system

Info

Publication number: CN108737056B
Application number: CN201810385609.3A
Authority: CN
Inventors: 俞锦
Original assignee: Wuhan Hongxin Technology Development Co Ltd
Current assignee: Wuhan Hongxin Technology Development Co Ltd
Priority date: 2018-04-26
Filing date: 2018-04-26
Publication date: 2021-02-19
Anticipated expiration: 2038-04-26
Also published as: CN108737056A

Abstract

The invention provides a TA (timing advance) determination method under carrier aggregation of an LTE-A (Long term evolution-advanced) system, which is characterized by comprising the following steps of: under carrier aggregation, aiming at a coverage scene, according to carrier configuration corresponding to UE, each configuration carrier measures a TA value of the UE, each configuration carrier reports the TA of the UE to a main carrier, and the main carrier processes a plurality of TA values measured by each carrier according to resource use conditions of the UE. The invention can determine a more proper TA value according to the resource occupation condition of the UE in the carrier aggregation scene so as to improve the uplink transmission reliability of the UE.

Description

TA (timing advance) determination method under carrier aggregation of LTE-A (Long term evolution-advanced) system

Technical Field

The invention relates to the technical field of wireless communication, in particular to a TA (timing advance) determining method under carrier aggregation of an LTE-A (Long term evolution-advanced) system.

Background

In the LTE system, the eNodeB may obtain the TA by timing testing the DMRS or SRS transmitted by the UE. TA is a parameter used to characterize the timing offset at which the eNodeB receives data transmitted by the UE. The closed loop process for keeping uplink synchronization between the UE and the eNodeB is as follows: the eNodeB obtains TA according to the measurement, and then sends a TA adjusting command to the UE through the PDSCH, and the UE adjusts according to the received TA so as to keep the uplink synchronization of the UE and the eNodeB.

In the LTE-a system, the principle of uplink synchronization between the UE and the eNodeB is the same, and if each UE only occupies the resource of one cell, i.e. the resource on one carrier, the TA determination method may be the same as that in LTE. However, under carrier aggregation, one UE may occupy resources of multiple carriers, and the protocol provides that each UE has only one corresponding TA. Therefore, in the same coverage scene, the eNodeB sends the TA corresponding to the main carrier to the UE, and the UE performs uplink synchronization with all carriers according to the TA of one carrier without problems. However, in different coverage scenarios, TA values that need to be adopted for synchronization between the UE and different carriers should be different, and if only one TA corresponding to one carrier keeps synchronization between the UE and all carriers, there is a problem.

The existing invention mainly focuses on a scheme of how to issue multiple TAs to the UE, and is more prone to modifying the protocol, and there is no solution to the problem under the R10 protocol architecture.

The related keywords are as follows:

disclosure of Invention

The technical problem to be solved by the invention is that, under carrier aggregation, an eNodeB can measure TA values of a plurality of carriers, but only can issue 1 TA adjustment amount to UE, and how to determine the TA adjustment command issued to the UE so as to ensure the uplink transmission performance of the UE on each carrier.

The technical scheme adopted by the invention is a TA (timing advance) determining method under carrier aggregation of an LTE-A (Long term evolution-advanced) system, under the carrier aggregation, aiming at a coverage scene, according to carrier configuration corresponding to UE (user equipment), each configured carrier measures a TA (timing advance) value of the UE, each configured carrier reports the TA of the UE to a main carrier, and the main carrier processes a plurality of TA values measured by each carrier according to the resource use condition of the UE.

And setting the counters of the continuous unoccupied resources of each carrier UE as T1, T2, … and TN, wherein N is the number of carriers configured by the UE, and when a certain counter meets the condition, reserving the TA value corresponding to the carrier as a useful TA value.

And if no counter satisfies the condition, determining that the TA value of the UE is finally the corresponding TA measured by the primary carrier.

Moreover, a certain counter satisfies the condition that it is smaller than the preset threshold value Tth.

And after the main carrier schedules the UE in each TTI, counting resource occupation situations of the UE on all carriers, setting a counter Tj +1 if the UE does not occupy uplink or downlink resources on a carrier CCj, and setting Tj to 0 if the UE occupies uplink or downlink resources on the carrier CCj, where j is 1,2, …, N.

Furthermore, the useful TA value is compromised by taking the average.

The invention provides a solution, under carrier aggregation, aiming at a coverage scene, according to carrier configuration corresponding to UE, each configuration carrier measures a TA value of the UE, each configuration carrier reports the TA of the UE to a main carrier, and the main carrier processes a plurality of TA values measured by each carrier according to the resource use condition of the UE to obtain a TA adjustment value most suitable for the UE and sends the TA adjustment value to the UE so as to ensure that the uplink transmission performance is improved.

The key innovation points of the invention are as follows:

1. the TA corresponding to the UE measured by each carrier wave is reported to the main carrier wave uniformly and is processed by the main carrier wave in a centralized way;

2. according to the resource occupation condition of the UE, removing useless TA values, so that the determined TA values are more suitable for the UE;

3. and finally determining the TA adjustment quantity transmitted to the UE by carrying out compromise on a plurality of useful TA values, so that the uplink transmission reliability of the UE on a plurality of carriers can be ensured.

Drawings

FIG. 1 is a schematic flow chart of an embodiment of the present invention.

Detailed Description

The technical scheme of the invention is explained by combining the drawings and the embodiment.

The invention provides that TA measurement is carried out on a plurality of carriers configured for UE, the TA value corresponding to each carrier is reported to a main carrier, and the main carrier processes the plurality of measured TA values according to the resource use condition of the UE to obtain the TA adjusting value most suitable for the UE and sends the TA adjusting value to the UE.

In the embodiment of the invention, under carrier aggregation, aiming at a coverage scene, each configuration carrier measures the TA value of UE according to the carrier configuration corresponding to the UE, each configuration carrier reports the TA of the UE to a main carrier, and the main carrier processes a plurality of TA values measured by each carrier according to the resource use condition of the UE.

The embodiment is realized by adopting the following flow:

step one, determining a main carrier: setting carrier sets configured by each camping UE to be CC1, CC2, …, CCn (default CC1 is a primary carrier, and the others are secondary carriers), a TA value corresponding to each carrier is TA1, TA2, …, TAn, and a continuous unoccupied resource counter of each carrier UE is T1, T2, …, TN, where N is the number of carriers configured by the UE, TA values TA1, TA2, … corresponding to each carrier, and an initial value of TAn is TAinit, which is a preset parameter, and may be 0 in specific implementation; the initial values of the continuous unoccupied resource counters T1, T2, … and TN are all set to be 0, the corresponding threshold value is Tth, and the suggested value range is 0 to 1282.

Step two, after the main carrier schedules the UE in each TTI, counting resource occupation conditions of the UE on all carriers, if the UE does not occupy uplink resources or downlink resources on the carrier CCj, setting a counter Tj to be Tj +1, and if the UE occupies the uplink resources or the downlink resources on the carrier CCj, setting Tj to be 0, wherein j is 1,2, …, N;

in the standards of 3GPP LTE and LTE-a, it is generally assumed that 1TTI is 1ms and is a basic unit of time under the control of radio resource management (scheduling, etc.).

And step three, each auxiliary carrier CCi measures the TAi according to the DMRS or SRS corresponding to the UE, when the corresponding TAi is measured, the corresponding TAi value is reported to the main carrier, the main carrier updates the TAi according to the received result, wherein i is an integer from 2 to n, and meanwhile, the main carrier CC1 measures the corresponding TA1, and then the TA1 is updated.

In specific implementation, the step two and the step three can be two independent steps without strict prepositive relation.

Step four, the main carrier processes a plurality of measured TA values according to the resource use condition of the UE to obtain a TA adjusting value which is most suitable for the UE and sends the TA adjusting value to the UE, the method comprises the following substeps,

A) let n be an integer with an initial value of 1,

B) according to a counter Tn corresponding to the UE, if Tn < Tth, putting TAN into a set U, n + +, otherwise, directly n + +;

C) if N > N, entering the step D), otherwise, returning to the step B);

D) and if the set U is empty, determining that the TA value of the UE is finally TA1, and if the set U is not empty, determining that the TA value of the UE is finally averaged for all TA values in the set U. The value taking is equivalent to performing compromise on the calculated TA values on all the carriers, and the value taken out is more suitable for all the carriers corresponding to the set U than directly selecting a certain Ta value.

E) And D) generating a corresponding TA adjusting command according to the TA determined by the D), and issuing the TA adjusting command to the UE through the main carrier.

The invention removes the useless TA value, and if the counter corresponding to a certain carrier reaches the threshold, the UE does not occupy the resource corresponding to the carrier for a long time through the continuous unoccupied resource counter corresponding to each carrier, so that the TA value corresponding to the carrier can be removed.

For example, in a scenario where carriers do not cover, the number of carriers configured by 1 UE is 3, where the largest coverage area is the primary carrier, and the other two small-coverage areas are the secondary carriers.

TA measurement is carried out on 3 carriers configured for the UE, TA values corresponding to the carriers are reported to a main carrier, the main carrier processes the measured TA values according to the resource use condition of the UE, and the TA adjustment value most suitable for the UE is obtained and sent to the UE.

The method comprises the following specific steps:

the method comprises the following steps: the primary carrier determines a carrier set CC1, CC2, CC3(CC1 is the primary carrier) configured for each resident UE, TA values TA1, TA2, TA3 corresponding to each carrier, and continuous unoccupied resource counters T1, T2, and T3 corresponding to each carrier, where a TA initial value corresponding to each carrier is TAinit, a continuous unoccupied resource counter initial value is 0, and a threshold value is Tth;

step two: after the main carrier wave schedules the UE in each TTI, counting the resource occupation conditions of the UE on all carrier waves, if the UE does not occupy uplink resources or downlink resources on the carrier waves CCj, setting a counter Tj to be Tj +1, and if the UE occupies the uplink resources or the downlink resources on the carrier waves CCj, setting the counter Tj to be 0, wherein j is 1 to 3;

step three: the auxiliary carrier CCi measures the TAi according to the DMRS or SRS corresponding to the UE, when the corresponding TAi is measured, the corresponding TAi value is reported to the main carrier, the main carrier updates the TAi according to the received result, wherein i is an integer from 2 to 3, the main carrier CC1 updates the TA1 when the corresponding TA1 is measured, and the step four is entered;

note that: the second step and the third step are two independent steps without strict prepositive relation.

N is an integer having an initial value of 1

Step four: a counter Tn corresponding to the UE, if Tn < Tth, putting TAN into a set U, n + +, otherwise, entering the step five if n >3, otherwise, repeating the step four;

step five: and if the set U is empty, determining that the TA value of the UE is TA1, and if the set U is not empty, averaging the TA values of the UE for all the TA values in the set U.

Step six: and determining a corresponding TA adjusting command according to the TA, and issuing the TA adjusting command to the UE through the main carrier.

In specific implementation, the technical scheme of the invention can realize automatic operation by adopting a computer software flow.

The foregoing is a more detailed description of the present invention that is presented in conjunction with specific embodiments, and the practice of the invention is not to be considered limited to those descriptions. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.

Claims

1. A TA determination method under LTE-A system carrier aggregation is characterized in that: under carrier aggregation, aiming at a coverage scene, according to carrier configuration corresponding to UE, each configuration carrier measures a TA value of the UE, each configuration carrier reports the TA of the UE to a main carrier, and the main carrier processes a plurality of TA values measured by each carrier according to the resource use condition of the UE, wherein the method comprises the steps of removing useless TA values according to the resource occupation condition of the UE, carrying out compromise on the residual useful TA values, obtaining a TA adjustment value most suitable for the UE and issuing the TA adjustment value to the UE, and realizing the purpose of ensuring the improvement of uplink transmission performance;

removing useless TA values by a continuous unoccupied resource counter corresponding to each carrier, and if the counter corresponding to a certain carrier reaches a threshold, indicating that the UE does not occupy the resource corresponding to the carrier for a long time, removing the TA values corresponding to the carriers;

the useful TA value is subjected to compromise, namely, an average value is taken;

the implementation process comprises the following steps of,

step one, determining a main carrier: setting carrier sets configured by each resident UE as CC1, CC2, …, CCN and CC1 as main carriers and the other carriers as auxiliary carriers; the TA value corresponding to each carrier is TA1, TA2, … and TAN, and the continuous unoccupied resource counter of each carrier UE is T1, T2, … and TN, wherein N is the carrier number configured by the UE; the TA values TA1, TA2 and TA … corresponding to each carrier are all set to TAinit as initial values, and the TAinit is a preset parameter; setting the initial values of the continuous unoccupied resource counters T1, T2, … and TN to be 0, and setting the corresponding threshold value to Tth;

step three, each auxiliary carrier CCi measures the TAi according to the DMRS or SRS corresponding to the UE, when the corresponding TAi is measured, the corresponding TAi value is reported to the main carrier, the main carrier updates the TAi according to the received result, wherein i is an integer from 2 to n, and meanwhile, the main carrier CC1 measures the corresponding TA1, and then the TA1 is updated;

A) let n be an integer with an initial value of 1;

C) if N > N, entering the step D), otherwise, returning to the step B);

D) if the set U is empty, the TA value of the UE is finally determined to be TA1, and if the set U is not empty, the TA value of the UE is finally determined to be the average value of all TA values in the set U;

2. The method for determining TA in carrier aggregation in LTE-A system according to claim 1, wherein: the preset threshold value Tth ranges from 0 to 1282.