WO2012109929A1

WO2012109929A1 - Lte time advance adjusting method and base station

Info

Publication number: WO2012109929A1
Application number: PCT/CN2011/082214
Authority: WO
Inventors: 余秋星; 陈琼
Original assignee: 中兴通讯股份有限公司
Priority date: 2011-02-17
Filing date: 2011-11-15
Publication date: 2012-08-23
Also published as: CN102647781A

Abstract

Disclosed are an LTE timing advance adjustment method and a base station. The average value of a plurality of currently newest time offset instantaneous values is used as an effective time offset value for a target UE, and issuing of a timing advance adjustment command to the target UE is confirmed, thus improving the accuracy of a time offset measurement, preventing timing advance adjustment inaccuracy resulting from inaccurate measurement due to noise and interference during the time offset measurement, or even the problem of uplink desynchronization, and in particular, increasing greatly the accuracy of timing advance adjustment under a condition of low signal-to-noise ratio. The plurality of time offset instantaneous values are selected flexibly, thus reducing greatly the complexity of implementing timing advance adjustment while ensuring accuracy. Reliability of timing advance adjustment under conditions of discontinuous scheduling and continuous scheduling are both solved and improved, thus improving greatly the accuracy and efficiency of timing advance adjustment, and ultimately increasing system throughput.

Description

LTE time advance adjustment method and base station

The present invention relates to the field of wireless communication technologies, and in particular, to an LTE time advance adjustment method and a base station. Background technique

In the LTE (Long Term Evolution) system, TA (Time Advance) is used to characterize the timing deviation of the data sent by the eNodeB (evolved NodeB) to the UE (User Equipment). The parameters. In order to maintain the uplink synchronization, the eNodeB instructs the UE to send a DMRS (DeModulation Reference Signal) or a SRS (Sounding Reference Signal) at a specified time. After the timing measurement, the eNodeB passes the physical downlink shared channel. The time advance adjustment command is sent to the UE for adjustment to maintain uplink synchronization between the UE and the eNodeB.

In LTE, the time advance adjustment command is expressed in multiples of 16 times Ts (lTs is the basic time unit of LTE) with respect to the current uplink timing, and is controlled by the MAC (Medium/Media Access Control) control unit. Come and send. The MAC control unit carries a 6-bit time advance adjustment command Γ to indicate the relative absolute adjustment amount N with respect to the current. The relative adjustment of _w , the range of values is Γ = 0,1, ...,63, then the new absolute adjustment is expressed as N _TA , _new = N + (T _A - 31)x l6 , and the unit is Ts.

In the prior art, the base station generally obtains a smoothed value according to the measured instantaneous value or based on the instantaneous value, and then notifies the UE to perform TA adjustment. In the prior art, when the uplink signal-to-noise ratio is relatively high, the problem is not large, but in the case of low SNR, the measured instantaneous value is easily affected by noise and interference, and even the measurement at the adjacent time is obtained. The result will fluctuate in a wide range, so the time advance adjustment based on the prior art will cause the base station to process the uplink received signal. The FFT (Fast Fourier Transformation) window contains information of adjacent symbols and introduces ISI (Inter Symbol Interference), which greatly deteriorates the performance of the uplink demodulation signal. System throughput has decreased. Summary of the invention

The main object of the present invention is to provide a time adjustment method and base station for LTE to improve the accuracy and efficiency of time advance adjustment.

The technical solution adopted by the present invention to solve the technical problem thereof is:

A time advance adjustment method for LTE, including:

The base station starts a TA timer;

The base station measures and records the time-offset instantaneous value of the target UE;

The base station saves the latest time-offset instantaneous value and uses the average value as the effective time-offset value. Before the TA timer expires, the base station sends a time advance adjustment command according to the valid time-offset period, and restarts the TA timer.

Preferably, the condition for starting the TA timer is: the UE completes the random access procedure, or the base station completes the delivery timing advance adjustment command.

Preferably, the base station measures and records the time-offset instantaneous value of the target UE, and specifically includes: calculating the time according to the channel response phase difference between adjacent or separated subcarriers of the uplink demodulation reference signal DMRS or the sounding reference signal SRS. The partial instantaneous value is obtained, or the time-offset instantaneous value is obtained according to the arrival time of the first path or the strongest path of the channel estimated by the DMRS or the SRS.

Preferably, the base station adjusts the command according to the effective time offset period before the timeout of the TA timer, which specifically includes:

Before the TA timer expires, according to the calculated valid time offset value 73⁄4 _# and the TA expected value _{3⁄4 rget} , a time advance adjustment command 4C is generated, wherein when the effective offset value _# minus the TA expected value 73⁄4 _{tarefrt is} greater than 8, then the time Adjust the command in advance to 32; when valid, the offset value is ∑4 minus When the TA expectation value 73⁄4 _{tagfrt is} less than -8, the time advance adjustment command 23⁄4C is 30; when the value is valid in other cases, the time advance adjustment command ∑4C is 31, or the time advance adjustment command is generated according to the formula:

A ― Τ Λ

TAC = round (-^ + 31

16

Where rowm (.) represents a rounding operation.

The invention also provides a base station, comprising:

a timer start unit, configured to start a TA timer;

a measurement recording unit, configured to measure and record a time-offset instantaneous value of the target UE;

The calculation processing unit is configured to save the latest time-offset instantaneous value and use the average value as the effective time offset value;

The adjustment command is sent to the pre-adjustment command according to the valid period offset period before the TA timer expires, and the TA timer is restarted.

Preferably, the timer starting unit is configured to: start a TA timer when the UE completes the random access procedure, or the base station completes the delivery timing advance adjustment command.

Preferably, the measurement recording unit is configured to: calculate the time-offset instantaneous value according to a channel response phase difference between adjacent or spaced subcarriers of the DMRS or the SRS, or estimate the first path of the channel according to the DMRS or the SRS Or the arrival time of the strongest path is the instantaneous value of the time offset.

Preferably, the adjustment command issuing unit is further configured to: before the TA timer expires, generate a time advance adjustment command TAC according to the calculated valid time offset value 73⁄4 _# and the TA expected value r4^ _t , where, when valid When the time offset value 73⁄4 _# minus the TA expectation value is greater than 8, the time advance adjustment command 73⁄4c is 32; when the effective offset value _# minus the expected value r4^ _{t is} less than -8, the time advance adjustment command 73⁄4c is 30; When the value is valid in other cases, the time advance adjustment command 4C is 31, or the time advance adjustment command is generated according to the formula:

TA _ff _ TA

TAC = round (-^ + 31

16 Where rowm (.) represents a rounding operation.

The technical solution of the present invention has the following beneficial effects: The LTE time adjustment method and the base station provided by the present invention use the current average value of multiple time-offset instantaneous values as the effective time-offset value of the target UE, and determine the target UE. The pre-adjustment command can be used to improve the accuracy of the time-biased measurement, avoiding the inaccurate adjustment of the time caused by the measurement inaccuracy caused by the noise and interference of the time-biased measurement, and even causing the problem of uplink out-of-step, especially The accuracy of time advance adjustment under low SNR is improved; flexible selection of multiple time-offset instantaneous values can greatly reduce the implementation complexity of time advance adjustment while ensuring accuracy; for discontinuous scheduling and continuous read scheduling The reliability of the time adjustment of the situation can be solved and improved, and the adjustment precision and efficiency of the time advancement are greatly improved, thereby ultimately improving the system throughput. DRAWINGS

FIG. 1 is a schematic flowchart of a method according to an embodiment of the present disclosure;

FIG. 1 is a schematic structural diagram of a base station according to an embodiment of the present invention.

The implementation, functional features and advantages of the objects of the present invention will be further described in conjunction with the embodiments herein. detailed description

The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment of the present invention provides a time advance adjustment method for LTE, where the steps of the method are implemented by a base station, as shown in FIG. 1, the method includes the following steps:

S110. The base station starts the TA timer. In other embodiments, the condition for starting the TA timer is: the UE completes the random access procedure, or the base station completes the delivery timing advance adjustment command. S120: The base station measures and records the time-offset instantaneous value of the target UE. In other embodiments, the S120 specifically includes:

Obtaining the time-offset instantaneous value according to a channel response phase difference between adjacent or spaced subcarriers of the DMRS or SRS, or estimating a first path or a strongest path of the channel according to DMRS or SRS (the strongest path is: power) The arrival time of the largest diameter is obtained as the time-biased instantaneous value.

S130. The base station saves the latest time-offset instantaneous value, and takes the average value as the effective time offset value; wherein, the selection of the time-shifted instantaneous value may be selected according to the signal-to-noise ratio or taken as a fixed value. If the signal-to-noise ratio is selected, the value is large when the signal-to-noise ratio is low, and the value is small when the signal-to-noise ratio is high.

S140: Before the TA timer expires, the base station sends a time advance adjustment command according to the valid time offset period, and restarts the TA timer. By repeating S120~S140, the adjustment process of the next time advance adjustment period can be performed.

In other embodiments, the S140 specifically includes:

Before the TA timer expires, based on the calculated effective time offset value 73⁄4 _# and TA expected value

_{3⁄4 rget} , generating a time advance adjustment command 4C, wherein, when the valid offset value _# minus the TA expectation value is greater than 8, the time advance adjustment command 73⁄4c is 32; when valid, the offset value is 73⁄4 _# minus

ΤΑ When the expected value is less than -8, the time advance adjustment command 73⁄4c is 30; when the deviation is valid in other cases, the time advance adjustment command 4C is 31, or the time advance adjustment command 73⁄4c is generated according to the formula, the formula is:

ΤΑ ^ - ΎΑ

TAC = round (-^ + 31

16

Where rowm (.) represents a rounding operation.

The time adjustment method of the LTE provided by the embodiment of the present invention uses the current average value of the plurality of time-offset instantaneous values as the effective time offset value of the target UE, and determines that the time advance adjustment command is sent to the target UE, which can improve the time offset measurement. Accuracy, avoiding inaccurate adjustment of time due to measurement inaccuracy caused by noise and interference in time-biased measurements, and even causing up-synchronization The problem, in particular, greatly improves the accuracy of time advance adjustment under low SNR; flexible selection of multiple time-offset instantaneous values can greatly reduce the implementation complexity of time advance adjustment while ensuring accuracy; The reliability of the time adjustment of scheduling and continuous read scheduling can be solved and improved, and the adjustment precision and efficiency of time advancement are greatly improved, thereby ultimately improving system throughput.

An embodiment of the present invention further provides a base station. As shown in FIG. 2, the base station includes:

The timer starting unit 210 is configured to start the TA timer. In other embodiments, the timer starting unit 210 is configured to complete the random access procedure in the UE, or the base station completes the scheduling advance adjustment command. Start the TA timer under the conditions.

The measurement recording unit 220 is configured to measure and record a time-offset instantaneous value of the target UE. In other embodiments, more specifically, the measurement recording unit 220 is configured to use between adjacent or separated subcarriers according to the DMRS or the SRS. The time-shift instantaneous value is obtained by calculating the channel response phase difference, or the time-offset instantaneous value is obtained according to the arrival time of the first path or the strongest path of the channel estimated by the DMRS or the SRS.

The calculation processing unit 230 is configured to save the latest time offset instantaneous value, and use the average value as the effective time offset value;

The adjustment command issuing unit 240 is configured to: before the TA timer expires, issue a time advance adjustment command according to the valid time offset period, and restart the TA timer.

In other embodiments, the adjustment command issuing unit 240 is further configured to generate a time advance adjustment command according to the calculated valid time offset value _# and the TA expected value r4^ _t before the TA timer expires. 4C , wherein, when the effective offset value _# minus the TA expected value 73⁄4 _{target is} greater than 8, the time advance adjustment command 4C is 32; when valid, the offset value 73⁄4 _# minus the TA expectation value ^ _{gfrt is} less than -8, then the time advance The adjustment command 4C is 30; when the value is other value when valid, the time advance adjustment command 4C is 31, or the time advance adjustment command TAC is generated according to the formula, and the formula is: Where rowm (.) represents a rounding operation.

The base station provided by the embodiment of the present invention uses the current average value of multiple time-offset instantaneous values as the effective time offset value of the target UE, and determines the time advance adjustment command to be delivered to the target UE, which can improve the accuracy of the time-offset measurement and avoid Due to the influence of noise and interference caused by time-biased measurement, the time advance adjustment caused by measurement inaccuracy is inaccurate, and even the problem of uplink out-of-step is caused, especially the accuracy of time advance adjustment under low SNR is greatly improved; Selecting multiple time-offset instantaneous values can greatly reduce the implementation complexity of time advance adjustment while ensuring accuracy; the reliability of time advance adjustment for discontinuous scheduling and continuous read scheduling can be solved and improved. The adjustment accuracy and efficiency of the time advancement are greatly improved, thereby ultimately improving the system throughput.

The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalents, and improvements made within the spirit and scope of the present invention should be included in the scope of the present invention. Inside.

Claims

Claim

A time advance adjustment method for LTE, characterized in that:

Base station startup time advancement TA timer;

The base station measures and records the time-offset instantaneous value of the target user equipment UE;

2. The method according to claim 1, wherein the condition for starting the TA timer is: the UE completes the random access procedure, or the base station completes the delivery timing advance adjustment command.

The method according to claim 1, wherein the base station measures and records the time-offset instantaneous value of the target UE, which specifically includes:

Calculating the time-offset instantaneous value according to a channel response phase difference between adjacent or separated subcarriers of the uplink demodulation reference signal DMRS or the sounding reference signal SRS, or

The time-offset instantaneous value is obtained by estimating the arrival time of the first path or the strongest path of the channel according to the DMRS or SRS.

The method according to claim 1, wherein the base station sends a time advance adjustment command according to the valid time offset period before the TA timer expires, which specifically includes:

_{3⁄4 rget} , generating a time advance adjustment command 4C, wherein, when valid, the offset value _# minus the TA expected value 73⁄4 _{targf!t is} greater than 8, the time advance adjustment command is 32; when valid, the offset value is 73⁄4 _# minus

When the TA expectation value 73⁄4 _{targf!t is} less than -8, the time advance adjustment command is 30; when the value is other value when valid, the time advance adjustment command 4C is 31, or the time advance adjustment command is generated according to the formula:

A ― Τ Λ

TAC = round (-^ + 31

16 Where rowm (.) represents a rounding operation.

5. A base station, comprising:

a timer start unit, configured to start a TA timer;

The base station according to claim 5, wherein the timer starting unit is configured to: start the TA timer when the UE completes the random access procedure, or the base station completes the delivery timing advance adjustment command.

The base station according to claim 5, wherein the measurement recording unit is configured to: calculate the time-offset instantaneous value according to a channel response phase difference between adjacent or spaced subcarriers of the DMRS or the SRS, or The time-offset instantaneous value is obtained according to the DMRS or SRS estimating the arrival time of the first path or the strongest path of the channel.

The base station according to claim 5, wherein the adjustment command issuing unit is further configured to: before the TA timer expires, generate a time advance adjustment according to the calculated valid time offset value _# and the TA expected value. The command 73⁄4C, wherein, when valid, the offset value 73⁄4 _# minus the TA expected value 73⁄4 _targ e _{t is} greater than 8, the time advance adjustment command is 32; when valid, the offset value 73⁄4 _# minus the TA expectation value 4 _{tagfrt is} less than -8, Then, the time advance adjustment command 4C is 30; when the value is valid in other cases, the time advance adjustment command is 31, or the time advance adjustment command 4C is generated according to the formula, the formula is:

ΤΑ ^ - ΎΑ

TAC = round (-^ + 31

16

Where rowm (.) represents a rounding operation.