CN1983850B - A Power Control Method for Combined Service in Mobile Communication System - Google Patents

Abstract

The invention is concerned with the power controlling method for the combination operation in the mobile communication system, including: confirms the signal-to-interference-ratio (SIR) target value of the current each transmission channel; selects the maximum value from the target value as the current power controlling target value; gets power controlling bit and processes the emission power control according to the target value. The invention is: each maximum of the is the current signal-to-interference-ratio (SIR) target value, in order that the transmission channel signal-to-interference-ratio (SIR) target value with the worst transmission quality convergences to process the power controlling signal-to-interference-ratio (SIR) target value, ensures the transmission quality of the transmission channel and also other transmission channel, saves the emission power.

Description

A Power Control Method for Combined Service in Mobile Communication System

technical field

The invention relates to a power control method of a mobile communication system, in particular to a power control method of combined services in the mobile communication system.

Background technique

The power control of the mobile communication system can be divided into uplink power control for controlling the transmit power of the terminal and downlink power control for controlling the transmit power of the base station. At the same time, according to whether the terminal and the base station participate in power control at the same time, it can be divided into open-loop power control and closed-loop power control.

In the uplink power control of closed-loop power control, the radio network controller calculates the block error rate according to the decoding result of the terminal received signal sent by the base station, and calculates a signal-to-interference ratio target value according to the target value of the block error rate, and the base station Comparing the SIR target value of the radio network controller with the SIR measurement value of the received terminal signal, a power control bit for adjusting the transmission power of the terminal is obtained, and the terminal adjusts the transmission power according to the power control bit.

In the downlink power control of closed-loop power control, the terminal calculates the downlink receiving block error rate and SIR measurement value, and calculates a SIR target value according to the block error rate target value, and the terminal compares the SIR target value with the SIR measurement value. value, thereby obtaining the power control bit, and the base station adjusts the transmission power according to the power control bit.

Closed-loop power control can be divided into inner-loop power control and outer-loop power control. In the outer loop power control of a single service, if the measured value of the block error rate is higher than the target value of the block error rate, the target value of the signal-to-interference ratio will be increased, and if the measured value of the block error rate is lower than the target value of the block error rate, the target value of the signal-to-interference ratio will be reduced. value. By setting the adjustment amount of the signal-to-interference ratio target value to be proportional to the difference between the measured value of the block error rate and the target value of the block error rate, the actual block error rate can be made to reach the set target value.

For the combined service requested by the multi-service user terminal, there are two solutions for controlling the power of the outer loop in the prior art.

One of the schemes is to firstly select a transmission channel of a main service to perform outer-loop power control, while the communication quality of other transmission channels is satisfied through rate matching. That is, the rate matching factor of each transmission channel is set, and the rate matching factor determines the power allocation ratio of each bit among the transmission channels, so that when the reception quality of one transmission channel meets the requirements, the reception quality of other transmission channels also approximately meets the requirements . Using the above method, the block error rate of the transmission channel of the main service converges to the target value due to the effect of the outer loop power control, and the channel reception quality of other transmission channels is controlled by the reception quality of the main service. However, under a given receiving quality, the block error rate of the transmission channel is not completely determined, and will be restricted by various factors such as the channel model, which is why it is necessary to introduce closed-loop and outer-loop power control. Therefore, with the above method, the block error rate of the non-main business transmission channel shows a certain randomness, which may be higher than the target value or lower than the target value, and the required bit error rate cannot be guaranteed.

Another solution is that the SIR target value of the outer loop power control at the current moment is the sum of the SIR target value at the previous moment and the maximum value of the SIR target value adjustments in all transmission channels. The target value adjustment amount is a negative value when the SIR target value is reduced, and it is a positive value when the SIR target value is increased. The SIR target value adjustment amount is related to the measured value of the block error rate and the target value of the block error rate The difference is directly proportional.

In this control method, the current SIR target value will decrease only when all transmission channels require a lower SIR target value, and as long as any transmission channel requires an increase SIR target value, the current SIR target value will be reduced. The signal-to-interference ratio target value will increase.

Using this method to adjust the SIR target value, the result is that when any transmission channel in all transmission channels requires an increase in the SIR target value, the SIR target value will increase, so that no increase is required for other For the transmission channel with the SIR target value, there will be a phenomenon that the SIR target value is required to be reduced, but the SIR target value is actually increased, which will lead to the actual value of the block error rate of the other transmission channels mentioned above. The transmit power is wasted if it is lower than the set block error rate target value. In addition, the transmission channel corresponding to the maximum value of the SIR adjustment used to calculate the current SIR target value does not necessarily correspond to the SIR target value at the previous moment. Therefore, the currently calculated SIR value cannot be guaranteed. The target value of the interference ratio can satisfy a certain transmission channel. The more serious consequence is that the transmission quality of a certain transmission channel is the worst, so the SIR adjustment amount is the largest, and the SIR target value of the outer loop power control at the previous moment is higher than the SIR of this transmission channel The target value, which leads to the SIR target value for the outer loop power control at the current moment is higher than the SIR target value actually required by all transmission channels, which also causes a waste of transmit power.

Contents of the invention

Aiming at the shortcomings of the prior art, the present invention provides a power control method for combined services in a mobile communication system, which can reasonably control the transmission power, thereby saving the transmission power.

The power control method of combined service in the mobile communication system of the present invention, its step comprises:

Step 1: Determine the current SIR target value of each transmission channel, wherein, if it is not the initial power control, the SIR target value of each transmission channel at the current moment is equal to the SIR target value and the SIR target value at the previous moment respectively. The sum of adjustments compared to the target value;

Step 2, selecting a maximum value from the SIR target values of the above-mentioned transmission channels, and using the maximum value as the SIR target value of the current power control;

Step 3: Power control bits are obtained according to the SIR target value of the current power control, and transmit power control is performed.

In the above step 1, when controlling for the first time, the initial value of the SIR target value of each transmission channel is preset.

The above step 2 may further include, comparing the difference between the SIR target value of the current power control and the SIR target value adjustment base value with the SIR target value of any current transmission channel, and taking the maximum value of the two is the SIR target value of the corresponding transmission channel after updating.

In the above step 3, during the uplink power control, the terminal adjusts the transmission power according to the power control bit issued by the base station.

In the above step 3, during the downlink power control, the base station adjusts the transmission power according to the power control bit sent by the terminal.

Compared with the prior art, in the present invention, the maximum value of the SIR target value of each transmission channel is used as the current SIR target value, so that the SIR target value of the transmission channel with the worst current transmission quality converges to the current SIR target value. The signal-to-interference ratio target value for power control ensures the transmission quality of this transmission channel, while the transmission quality of other transmission channels is also guaranteed, and transmit power is saved. At the same time, by updating the target value of the signal-to-interference ratio, it is also ensured that there will be no transmission channel with a continuous high block error rate, thereby ensuring the transmission quality.

Description of drawings

FIG. 1 is a flow chart of a method for power control of a combined service in a mobile communication system according to the present invention.

Detailed ways

In the power control method for combined services in the mobile communication system of the present invention, the maximum value of the SIR target value of each transmission channel is used as the current SIR target value, so that the signal of the transmission channel with the worst current transmission quality The target value of the interference ratio converges to the target value of the signal-to-interference ratio currently under power control, ensuring the transmission quality of each transmission channel and saving transmission power.

The power control method of the combined service in the mobile communication system of the present invention will be further described below with reference to the accompanying drawings.

As shown in Figure 1, the power control method of combined service in the mobile communication system of the present invention comprises the following steps:

Step 101, determine the SIR target value of each transmission channel.

In this step, the SIR target value of each transmission channel at the current moment is equal to the sum of the respective SIR target value at the previous moment and the adjustment amount of the SIR target value. The adjustment base value of the signal-to-interference ratio target value is set according to the distribution requirements of the block error rate. Proportional to the difference between the rate target values. When the SIR target value of any transmission channel at the current moment is higher than the SIR target value of the transmission channel at the previous moment, the adjustment value of the SIR target value is a positive value; When the signal-to-interference ratio target value is lower than the signal-to-interference ratio target value of the transmission channel at the previous moment, the adjustment amount of the signal-to-interference ratio target value is a negative value. The SIR target value of any transmission channel at the current moment can be expressed by the following formula:

SIRtrch(n, i)=SIRtrch(n-1,i)+ΔSIRtrch(n,i).

Among them, SIRtrch(n, i) represents the SIR target value of any transmission channel at the current moment, SIRtrch(n-1, i) represents the SIR target value of the corresponding transmission channel at the moment before the current moment, ΔSIRtrch (n, i) represents the adjustment amount of the SIR target value of the corresponding transmission channel relative to the current SIR target value at the previous moment of the current moment. The above formula shows the situation when the transmission power is not controlled for the first time. When the transmission power is controlled for the first time, the initial value of the SIR target value can be preset. For example, the SIR target value of the corresponding transmission channel is set to The signal-to-interference ratio under normal conditions is slightly higher than the target value.

In step 102, a maximum value is selected from the SIR target values of the transmission channels, and the maximum value is used as the SIR target value of the current power control.

In this step, the SIR target values of the above-mentioned transmission channels are compared, and the largest SIR target value among them is selected as the SIR target value for current power control.

After determining the SIR target value required by the current power control according to the SIR target value of each transmission channel, the following situation may occur, that is, the block error rate of a transmission channel (assumed to be transmission channel A) converges to the target value, and another transmission channel (assumed to be transmission channel B) may have a very low block error rate, then the SIR target value corresponding to the transmission channel B is also very low, which will be much lower than the SIR in the current power control target value. In this way, when the environment of the transmission channel changes, more block errors may occur on the transmission channel B. Since the current SIR target value of transmission channel B is far lower than the SIR target value in the current power control, the SIR in the current power control can only be affected if the target value of the transmission channel is raised several times The target value, so, in this case, the transmission channel B still has a high continuous block error. In order to solve this problem, it is necessary to update the respective SIR target values after calculating the current SIR target values of each transmission channel, and use the updated SIR target values as their respective SIR target values, as follows The SIR target value required for power control is calculated with the updated SIR target value of each transmission channel at a moment.

The method for updating the SIR target value of each current transmission channel is: the difference between the SIR target value of the current power control and the SIR target value adjustment base value is compared with the SIR target value of any current transmission channel. Comparison, take the maximum value of the two as the SIR target value of the corresponding transmission channel after the update. The SIR target value adjustment base value is set according to the requirements of the block error rate distribution, and this value determines the continuous error rate. the number of blocks.

For the SIR target value of any transmission channel after the above update, the formula can be expressed as:

SIR'trch(n, i)=max(SIRtrch(n,i), SIRcctrch(n)-SIRthreshold).

In the formula, SIR`trch(n, i) is the SIR target value of any transmission channel after updating, SIRtrch(n, i) is the current SIR target value of any transmission channel, and SIRcctrch(n) is the current SIR target value for power control, SIRthreshold adjusts the base value for the SIR target value.

In step 103, a power control bit is obtained according to the SIR target value of the current power control, and transmit power control is performed.

For uplink power control, the base station compares the current signal-to-interference ratio target value determined above with the current signal-to-interference ratio measurement value to obtain the power control bit, and sends the power control bit to the terminal, and the terminal controls the Bits adjust transmit power.

For downlink power control, the terminal compares the SIR target value determined above with the current SIR measurement value to obtain the power control bit, and sends the power control bit to the base station, and the base station adjusts the transmission according to the received power control bit. power.

It can be seen from the above that, in the power control method of the present invention, the SIR target value in the current power control can be determined, and the SIR target value is required by the inner loop power control. In the inner loop power control, the power control bit is obtained by comparing the SIR target value with the SIR measurement value, and finally the power transmitter adjusts the transmission power according to the power control bit.

The application of the present invention overcomes that in the existing power control method, the simple sum of the SIR target value at the previous moment and the maximum value of the SIR target value adjustment value of each transmission channel is the SIR target value at the current moment, As a result, the target signal-to-interference ratio at the current moment is not the target value of the signal-to-interference ratio required by any transmission channel, and causes the disadvantage of wasting transmit power.

In the present invention, the maximum value of the SIR target value of each transmission channel is taken as the SIR target value for power control at the current moment, which satisfies the transmission quality of the transmission channel with the highest block error rate among all transmission channels, and makes other The transmission channel does not have an excessively high block error rate, thereby ensuring the transmission quality of all transmission channels.

If the transmission quality of a certain transmission channel is relatively good, then the calculated SIR target value of the transmission channel will also be lower than the corresponding SIR target values of other transmission channels with poor transmission quality. Therefore, in the present invention, the SIR target value for power control is the maximum value of the SIR target values in all transmission channels, and the SIR target value corresponds to the transmission channel with the worst transmission quality. When the transmission quality of the transmission channel with the worst transmission quality is guaranteed, the transmission quality of other transmission channels is also guaranteed. And, because the signal-to-interference ratio target value selected as the current power control in the present invention is the signal-to-interference ratio target value corresponding to the transmission channel with the worst transmission quality among all transmission channels, therefore, the selected signal-to-interference ratio target value is also guaranteed The value is reasonable, and the power control is performed based on the signal-to-interference ratio target value, which saves transmission power better than the power control method in the prior art.

Although the embodiment of the present invention has been disclosed as above, it is not limited to the use listed in the specification and implementation, it can be applied to various fields suitable for the present invention, and it can be easily understood by those skilled in the art Therefore, the invention is not limited to the specific details and examples shown and described herein without departing from the general concept defined by the claims and their equivalents.

Claims (6)

1. the Poewr control method of composite service in the mobile communication system is characterized in that step comprises:

Step 1, determine the signal interference ratio desired value that each transmission channel is current, wherein, if not first power control, described each transmission channel equals the signal interference ratio desired value of each comfortable previous moment and the adjustment amount sum of signal interference ratio desired value in the signal interference ratio desired value of current time;

Step 2 is selected maximum from the signal interference ratio desired value of above-mentioned each transmission channel, with the signal interference ratio desired value of this maximum as current power control; The difference that the signal interference ratio desired value and the signal interference ratio desired value of current power control are adjusted base value is compared with the signal interference ratio desired value of current any one transmission channel, get that maximum is the signal interference ratio desired value of corresponding transmission channel after upgrading among the two;

Step 3, the signal interference ratio desired value of controlling according to above-mentioned current power draws power control bit, carries out transmitting power control.

2. Poewr control method as claimed in claim 1 is characterized in that, in the described step 1, when first power was controlled, the initial value of the signal interference ratio desired value of each transmission channel set in advance.

3. Poewr control method as claimed in claim 2 is characterized in that, described signal interference ratio desired value is adjusted base value and is provided with according to the Block Error Rate distributed needs.

4. Poewr control method as claimed in claim 1 is characterized in that the adjustment amount of described signal interference ratio desired value calculates according to the Block Error Rate of this transmission channel.

5. Poewr control method as claimed in claim 1 is characterized in that, in the described step 3, when uplink power control, terminal is regulated transmitting power according to the power control bit that the base station issues.

6. Poewr control method as claimed in claim 1 is characterized in that, in the described step 3, when descending power was controlled, the power control bit that send according to terminal the base station was regulated transmitting power.

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