CN101488786B - A method for controlling uplink power in a time division synchronous code division multiple access system - Google Patents

Abstract

The invention discloses an uplink power control method of a time-division synchronous CDMA access system, when the uplink of the time-division synchronous CDMA access system is transmitted discontinuously, for any one coding combined transmission channel positioned in an uplink discontinuous transmitting state, if the base station judges that the uplink signal in the uplink frame is not activated, so that a counter in no activated state adds 1, if the base station judges that the numerical value of the counter in no activated state is equal to the special burst generating period, so that the base station generates and distributes the power control command word for raising the uplink power to complete the uplink power control of the time-division synchronous CDMA access system when the uplink is transmitted discontinuously. According to the invention, even the uplink can not detect the SBs, the base station still can generate an appropriate power control command word to enable the terminal to improve the power and overcome the deterioration of wireless channels during the uplink is transmitted discontinuously.

Description

A method for controlling uplink power in a time division synchronous code division multiple access system

technical field

The present invention relates to the field of wireless communication, and more specifically relates to an uplink power control method during uplink discontinuous transmission of a Time Division-Synchronous Code Division Multiple Access (TD-SCDMA) system.

Background technique

The closed-loop power control technology is the basic technology in the TD-SCDMA system. In the closed-loop power control mechanism, the user equipment/base station periodically adjusts the transmission power according to the power control command carried by the feedback link from the base station/user equipment. Taking uplink power control as an example, after receiving the signal from the user equipment, the base station determines whether to increase or decrease the transmission power of the user equipment according to the SIR measurement value of the uplink signal, and generates a corresponding power control command. The base station transmits the power control command to the user equipment through the downlink feedback channel, and the user equipment adjusts the uplink transmission power after receiving the power control command.

For the TD-SCDMA system, if the base station or the high layer of the user equipment does not provide data to the coded combined transport channel (CCTrCH) within the transmission time interval (TTI), the base station and the user equipment can use the coded combined transport channel (CCTrCH) as a unit to implement Discontinuous Transmission (DTX). When discontinuous transmission (DTX) acts on a certain CCTrCH, the CCTrCH stops regular data transmission and changes to transmit special bursts (SBs, Special Bursts) at a certain period. The uplink SB transmission period is called SBGP (special burst generation period), the downlink SB transmission period is called SBSP (special burst scheduling period), see Figure 1. The implementation of discontinuous transmission has a positive effect on reducing air interface interference and saving equipment energy consumption. When the upper layer re-provides data to the Coded Combination Transport Channel (CCTrCH) in a certain TTI, the terminal immediately exits the uplink discontinuous transmission state in this TTI, and resumes the transmission of uplink data.

When uplink discontinuous transmission is implemented, the terminal periodically transmits uplink SBs to maintain the link, and the base station can generate an appropriate power control command word to perform uplink closed-loop power control according to the received SBs. Under normal circumstances, when uplink discontinuous transmission occurs, the base station and the terminal rely on the uplink SBs to maintain the closed-loop power control process in the above manner.

After the uplink discontinuous transmission occurs, the base station may not be able to detect the uplink SBs under certain wireless channel deterioration conditions, such as when the wireless channel is suddenly blocked and the path loss suddenly changes. question. After the uplink discontinuous transmission occurs, when the base station cannot detect the uplink SBs, the base station cannot generate a suitable power control command word through the measurement of the uplink signal according to the conventional method. If the channel deterioration condition continues, the base station cannot effectively use the closed-loop Power control is used to increase uplink power, so that the base station continues to detect uplink SBs. Therefore, after the uplink discontinuous transmission occurs, the base station needs to distinguish between the two situations of "the terminal does not transmit a signal" and "the terminal transmits a signal but the base station cannot detect it" in a certain way, so that even if the uplink cannot detect SBs, the base station still Appropriate power control command words can be generated to enable the terminal to increase power to overcome the deterioration of the wireless channel during uplink discontinuous transmission.

Contents of the invention

The technical problem to be solved by the present invention is to provide an uplink power control method of a time division synchronous code division multiple access system, so that even when the uplink cannot detect SBs, the base station can still generate a suitable power control command word to make the terminal increase the power To overcome the deterioration of the wireless channel during uplink discontinuous transmission.

In order to solve the above problems, the present invention provides an uplink power control method of a time division synchronous code division multiple access system. State coded combined transport channel,

If the base station judges that the uplink signal in the received uplink frame is not active, it will add 1 to the "inactive state" counter, and if the base station judges that the value of the "inactive state" counter is equal to the special burst generation period, the base station will raise The power control command word of the uplink power is sent out to complete the uplink power control of the time division synchronous code division multiple access system during uplink discontinuous transmission.

Further, the above method may further include, before the base station judges whether the uplink signal in the received uplink frame is activated, further includes the step of,

a1. The base station generates an uplink power control command word according to the received activated uplink special burst, and clears the "inactive state" counter;

a2. The base station receives and detects the uplink signal energy of each frame after the activated uplink special burst.

Further, the above method may further include, in the step a2, receiving and detecting the uplink signal energy of each frame after the activated uplink special burst, including: respectively receiving and detecting the uplink signal energy of each subframe in the frame detection.

Further, the above method may further include, for the frame structure of the time division synchronous code division multiple access system, one frame includes two subframes.

Further, the above method may further include that the base station determines whether the uplink signal in the uplink frame is active, including: when the energy of the uplink signal in each subframe of the frame is greater than the threshold T_active, indicating that the uplink signal in the uplink frame is active , where the threshold T_active is obtained through simulation according to the wireless environment.

Further, the above method may further include, if the base station judges that the uplink signal in the received uplink frame has been activated, then execute the step a1.

Further, the above method may further include, if the value of the "inactive state" counter is less than the special burst generation period, then performing the step a2.

Further, the above method may further include, after the base station generates and delivers the power control command word for increasing the uplink power, clearing the "inactive state" counter, and performing the step a2.

Compared with the prior art, the application of the present invention judges the situation that the terminal transmits SBs but the base station does not detect it by counting the uplink inactive state. When this situation occurs, the base station generates a power control to increase the uplink power The command word is issued and the closed-loop process of uplink power control is still maintained. When the SBs cannot be detected in the uplink, the base station can still generate an appropriate power control command word to make the terminal increase the power to overcome the deterioration of the wireless channel during the uplink discontinuous transmission.

Description of drawings

Figure 1 is a schematic diagram of the timing sequence of the uplink discontinuous state of the TD-SCDMA system;

Fig. 2 is a flow chart of the uplink power control method during the uplink discontinuous transmission of the TD-SCDMA system of the present invention.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.

The main concept of the present invention is that when discontinuous uplink transmission in TD-SCDMA system, for any coded combined transport channel (CCTrCH) in the uplink discontinuous transmission state,

If the base station judges that the uplink signal in the received uplink frame (frame) is not active, it will add 1 to the "inactive state" counter N_inactive. The power control command word of the link power is sent out to complete the uplink power control for the uplink discontinuous transmission of the TD-SCDMA system.

The uplink power control method when the TD-SCDMA system uplink discontinuous transmission of the present invention, for any code combination transport channel (CCTrCH) in the uplink discontinuous transmission state, as shown in Figure 2, specifically comprises the following steps:

Step 110, the base station generates an uplink power control command word according to the received activated uplink SBs, and clears the "inactive state" counter N_inactive;

Step 120, the base station receives and detects the uplink signal energy of each frame (frame) after the activated uplink SBs (special burst, Special Bursts);

Receive and detect the uplink signal energy of each frame (frame) after the activated uplink SBs", including: receiving and detecting the uplink signal of each subframe (subframe, 5ms) in the frame (frame, 10ms). For In the frame structure of TD-SCDMA, one frame (frame) includes two subframes (subframe).

Step 130, the base station judges whether the uplink signal in the uplink frame (frame) is activated, if so, execute step 110; otherwise, execute step 140;

"Judging whether the uplink signal in the uplink frame (frame) is active" includes: when the energy of the uplink signal in each subframe (subframe) of the frame (frame) is greater than the threshold T_active, it means that the uplink signal in the uplink frame is active, The threshold T_active is obtained through simulation according to the wireless environment.

Step 140, add 1 to the "inactive state" counter N_inactive;

Step 150, judge whether the value of "inactive state" counter N_inactive is equal to SBGP, if so, execute step 160; otherwise, (representing that N_inactive is less than SBGP), execute step 120;

The SBGP is the uplink SB transmission period, called SBGP (special burst generation period, special burst generation period), and the unit is frame (frame).

Step 160, generate and issue a power control command word for increasing the uplink power, clear the "inactive state" counter N_inactive, and execute step 120.

The above process continues during the uplink discontinuous transmission.

To sum up, by counting the uplink inactive state, it is judged that the terminal transmits SBs but the base station does not detect it. When this situation occurs, the base station generates and issues a power control command word to increase the uplink power. The closed-loop process of uplink power control is still maintained, and the reliability of uplink power control during discontinuous uplink transmission is enhanced.

The above is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any person familiar with the technology can easily think of changes or replacements within the technical scope disclosed in the present invention. , should be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the protection scope of the claims.

Claims (7)

1. An uplink power control method of a time division synchronous code division multiple access system, when the uplink discontinuous transmission of the time division synchronous code division multiple access system, for any code combination transmission channel in the uplink discontinuous transmission state, It is characterized in that, If the base station judges that the uplink signal in the received uplink frame is not active, then add 1 to the "inactive state" counter, and if the base station judges that the uplink signal in the received uplink frame is active, then clear the "inactive state" counter; If the base station judges that the value of the "inactive state" counter is equal to the special burst generation period, the base station generates a power control command word for raising the uplink power and sends it out to complete the TDSCDMA access system Uplink power control during uplink discontinuous transmission; wherein, the base station judges whether the uplink signal in the uplink frame is activated, including: when the uplink signal energy of each subframe of the frame is greater than the threshold T_active, indicating that the uplink signal in the uplink frame The uplink signal is activated, wherein the threshold T_active is obtained through simulation according to the wireless environment. 2. The method of claim 1, wherein Before the base station judges whether the uplink signal in the received uplink frame is activated, it also includes the step of, a1. The base station generates an uplink power control command word according to the received activated uplink special burst, and clears the "inactive state" counter; a2. The base station receives and detects the uplink signal energy of each frame after the activated uplink special burst. 3. The method of claim 2, wherein In the step a2, receiving and detecting the uplink signal energy of each frame after the activated uplink special burst includes: respectively receiving and detecting the uplink signal of each subframe in the frame. 4. The method of claim 3, wherein, For the frame structure of the TDSCDMA system, one frame includes two subframes. 5. The method of claim 4, wherein, If the base station judges that the uplink signal in the received uplink frame is activated, the step a1 is executed. 6. The method of claim 5, wherein, If the value of the "inactive state" counter is less than the special burst generation period, then step a2 is performed. 7. The method of claim 6, wherein, After the base station generates and delivers the power control command word for increasing the uplink power, the "inactive state" counter is cleared, and the step a2 is performed.

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