CN101895899B - Method and system for controlling uplink power - Google Patents

Abstract

The invention relates to the field of wireless communication, and discloses an uplink and downlink power control method and system, so that the interference of indoor communication to outdoor can be reduced. In the present invention, the downlink interference control threshold corresponding to the indoor cell is calculated according to the downlink signal sampling data of the adjacent cell; the uplink interference control threshold corresponding to the indoor cell is calculated according to the uplink signal sampling data of the indoor cell; The terminal in the indoor cell makes a judgment on the downlink and/or downlink transmission power. If the downlink transmission power of the terminal on the network side after power control is determined to be greater than the downlink interference control threshold according to the power control judgment result, power adjustment is not performed according to the judgment result. , and adjust the downlink transmit power of the terminal to the downlink interference control threshold. If it is determined according to the power control decision result that the uplink transmission power of the terminal after power control will be greater than the uplink interference control threshold, then the uplink transmission power of the terminal is adjusted to the uplink interference control threshold.

Description

Uplink power control method and system

technical field

The invention relates to the field of wireless communication, in particular to power control technology.

Background technique

Code Division Multiple Access (CDMA for short) communication system occupies a pivotal position in mobile communication, especially in the third generation of mobile communication (The Third Generation, referred to as "3G"), the three relatively mature standards All belong to the category of CDMA. In a CDMA system, because all users share the same frequency, the mutual interference problem is prominent, so power control is very critical. Whether it is uplink or downlink, it is very necessary to keep the transmit power at the minimum power level that can meet the communication quality requirements, because too small power will cause users to be dissatisfied with the communication quality, and too much power will reduce the operational efficiency of the communication system .

There are generally two power control methods in the prior art: open-loop power control and closed-loop power control.

Among them, the open-loop power control is mainly used to determine the initial transmission power of the user, or to adjust the transmission power when the code power of the user's received signal changes suddenly. The actual interference of the system and the effect of power control are determined by the closed-loop power control, which includes outer-loop power control and inner-loop power control.

The power control mechanism stipulated by 3GPP is shown in Figure 1, including outer loop power control and inner loop power control. The goal of "outer loop power control" is to timely adjust the target Signal to Interference Ratio ("SIR") value according to business needs, so that various services can have less error when the target SIR is reached. Block Error Rate (Block Error Rate, referred to as "BLER") to ensure service quality. The goal of "inner loop power control" is to adjust the power in time according to the adjusted target SIR value, so that the signal-to-noise ratio is basically constant.

Inner loop power control includes uplink power control and downlink power control. For uplink power control, the base station detects the SIR of the uplink between the base station and the terminal, and obtains the SIR measurement value. The value is used for power control, and the inner loop power control command TPC_CMD is sent to the terminal, TPC_CMD=f{C1, C2, C3, . . . , Cm}. Among them, C1, C2, C3, .. represent power control commands corresponding to a wireless connection between the terminal and the base station, and the final power control command is a function of commands received by each link. The mechanism of each power control command is:

When the measured SIR is smaller than the target SIR, an inner loop control command is sent to instruct the terminal to increase the uplink transmission power by one step, that is, when the SIR _{measurement is} <SIR _target , Ci=+1.

When the measured SIR is greater than the target SIR, an inner loop control command is sent to instruct the terminal to reduce the uplink transmission power by one step, that is, when the SIR _measurement >SIR _target , Ci=-1.

For downlink power control, the terminal measures the SIR of the downlink and reports the SIR measurement value. The base station performs power control according to the target SIR from the RNC and the SIR measurement value reported by the terminal, and instructs the base station to increase or decrease the downlink transmit power. The principle of specific judgment and indication is similar to that of uplink power control.

The effect that power control can achieve is: under various service conditions, the uplink SIR detected by the base station and the downlink SIR reported by the terminal converge to the corresponding target SIR.

The change of transmit power during the above power control process is shown in FIG. 2 . Among them, Pmax represents the maximum power allowed by the cell, Pmin represents the minimum power allowed by the cell, P1c represents the transmission power convergence value of the terminal at the edge of the cell, P2c represents the transmission power convergence value of the terminal close to the base station, and T'c represents the terminal close to the base station The power convergence time of T"c represents the power convergence time of the terminal at the edge of the cell.

It can be seen that the final transmission power of the terminal at the edge of the cell and the terminal near the base station can be controlled within the allowable power range of the cell. In Figure 2, the allowable power range of the cell = Pmax-Pmin, and this value does not change with the location of the terminal , is pre-determined by parameters.

The inventors of the present invention found that although the existing power control algorithm can be applied to the general network conditions of 3G, in some special scenarios, such as buildings with indoor coverage systems installed, there is a problem of excessive interference between indoor cells and outdoor cells ,As shown in Figure 3.

Specifically, due to the inevitable weakening of power in the transmission process, there is a large difference in the power convergence value between different terminals. The terminal at the edge of the cell or in an area with poor coverage, after power control, converges to the transmission The power is usually high, as shown in P1c in Figure 2; terminals located in the base station coverage center or areas with better coverage conditions usually converge to a lower transmit power after power control, as shown in P2c in Figure 2. Since both P1c and P2c are within the allowed power range of the cell, they are not limited in power control. However, for the indoor cells of small base stations, distributed antenna systems or wireless access points (AccessPoint, "AP") set inside the building, the edge part of the cell is adjacent to the outdoor cell, and in this part of the adjacent area In this case, if the transmit power of the terminal is too high, it will cause interference to the outdoor cell, especially in the case of tall buildings, the interference to the outdoor network will be greater, which may cause the contraction of the outdoor service cell, as shown in Figure 3.

Next, based on the actual Wideband Code Division Multiple Access (WCDMA) network test experience, select an outdoor scene to test the interference impact of indoor coverage signal leakage on outdoor signal coverage. In this test, the indoor distribution system is installed in the machine room on the 8th floor.

The test cases include testing outdoor cells under the conditions of constant indoor pilot power, increasing 3dB, decreasing 3dB, etc., and obtaining statistical results of test data on the outdoor road. Analysis shows:

1. The pilot power of the indoor cell changes by 3dB, the Ec (the received energy per chip) of the outdoor cell changes by 1.2 to 1.7dB, and the Ec/Io (the ratio of the received energy to the noise power spectral density per chip) changes by 0.3 to 0.5 dB. That is to say, when the pilot frequency power of the indoor cell increases by 3dB, the Ec of the outdoor cell will decrease by 1.2 to 1.7dB, and the Ec/Io will decrease by 0.3 to 0.5dB.

2. When changing (increasing and decreasing) the pilot power of the indoor coverage cell by 3dB, the soft handover ratio changes significantly, with an average change of 89.2% in the indoor environment and 45% in the outdoor environment. It can be seen that the increase of pilot power in indoor cells will lead to a large increase in soft handover between indoor cells and outdoor cells, occupying a large amount of cell resources, and in the process of soft handover, it is easy to cause call drop and other phenomena that affect user performance.

3. At a distance of 5 meters outdoors, the average value of the pilot power Ec of the outdoor cell is 5dB higher than the leaked output pilot power of the indoor, and the controllable soft handover ratio is about 30%. It can be seen that the indoor cell has a larger impact on the outdoor cell.

4. The indoor cell pilot power is 10dB higher than the outdoor pilot penetrating into the cell, and the soft handover ratio can be controlled at about 30%.

From this test case, it can be seen that the taller and denser the building where the indoor distribution system is installed, the greater the indoor interference to the outdoor will be.

Contents of the invention

The main technical problem to be solved by the embodiments of the present invention is to provide an uplink and downlink power control method and system, so that the interference of indoor communication to outdoor can be reduced.

In order to solve the above technical problems, an embodiment of the present invention provides a downlink power control method, including the following steps:

Calculate the downlink interference control threshold corresponding to the indoor cell according to the downlink signal sampling data of the adjacent cells of the indoor cell;

According to the power control related measurement value, the downlink transmission power of the terminal in the indoor cell is determined. If the downlink transmission power of the terminal on the network side after the power control is determined to be greater than the downlink interference control threshold according to the power control decision result, then the The downlink transmit power of the terminal is adjusted to the downlink interference control threshold.

Embodiments of the present invention also provide an uplink power control method, including the following steps:

Calculate the uplink interference control threshold corresponding to the indoor cell according to the uplink signal sampling data of the indoor cell;

Receive the actual uplink transmission power of the terminal reported by the terminal in the indoor cell;

According to the power control related measurement value, the power control judgment of the uplink transmission power of the terminal in the indoor cell is carried out. The uplink transmit power is adjusted to the uplink interference control threshold.

Embodiments of the present invention also provide a downlink power control system, including:

A calculation unit, configured to calculate the downlink interference control threshold corresponding to the indoor cell according to the downlink signal sampling data of the adjacent cells of the indoor cell;

The power control unit is used to perform power control judgment and power adjustment on the downlink transmission power of the terminal in the indoor cell according to the power control related measurement value;

The judging unit is used to judge whether the downlink transmission power of the terminal on the network side after power control will be greater than the downlink interference control threshold according to the power control judgment result of the power control unit, and if so, instruct the power control unit to transmit downlink to the terminal The power is adjusted to the downlink interference control threshold.

Embodiments of the present invention also provide an uplink power control system, including:

A calculation unit, configured to calculate the uplink interference control threshold corresponding to the indoor cell according to the uplink signal sampling data of the indoor cell;

a power receiving unit, configured to receive the actual uplink transmission power of the terminal reported by the terminal in the cell;

A power control unit, configured to perform power control judgment and power adjustment on uplink transmission power of terminals in the cell according to power control related measurement values;

The judging unit is used to judge whether the actual uplink transmission power of the terminal after the power control will be greater than the uplink interference control threshold according to the judgment result of the power control unit and the actual uplink transmission power of the terminal received by the power receiving unit, and if it is greater, indicate the power control The unit adjusts the actual uplink transmission power of the terminal to the uplink interference control threshold.

Compared with the prior art, the embodiment of the present invention has the main effect that in the case that there are outdoor neighboring cells around the indoor cell, the downlink power received by the terminal in the indoor cell and the uplink transmit power of the terminal can be controlled at one In a more suitable range, reduce the interference of indoor communication to outdoor. In addition, since the calculated uplink and downlink interference control thresholds are independently aimed at an indoor cell, the thresholds corresponding to each indoor cell may be different according to the specific environment, so that the power control can be fully integrated with the environment, so as to improve the effect of power control to the best.

Description of drawings

FIG. 1 is a schematic diagram of power control in the prior art;

FIG. 2 is a schematic diagram of signal changes under power control in the prior art;

FIG. 3 is a schematic diagram of interference from indoor cell signals to outdoor cell signals according to the prior art;

FIG. 4 is a schematic diagram of the principle of a downlink power control method according to a first embodiment of the present invention;

FIG. 5 is a flowchart of a downlink power control method according to a first embodiment of the present invention;

6 is a schematic diagram of the relationship between indoor and outdoor attenuation and distance changes in the downlink power control method according to the first embodiment of the present invention;

FIG. 7 is a schematic diagram of the principle of an uplink power control method according to a second embodiment of the present invention;

FIG. 8 is a flowchart of an uplink power control method according to a second embodiment of the present invention;

FIG. 9 is a structural diagram of a downlink power control system according to a third embodiment of the present invention;

Fig. 10 is a structural diagram of an uplink power control system according to a fourth embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solution and advantages of the present invention clearer, the following will further describe the implementation of the present invention in detail in conjunction with the accompanying drawings.

The first embodiment of the present invention relates to a downlink power control method, which is suitable for power control of indoor cells. This embodiment mainly includes three parts, as shown in FIG. 4 : 1. The detection terminal performs data sampling on the downlink signal of the adjacent cell in the indoor cell, and sends the sampled data to the base station of the indoor cell. 2. The base station calculates the downlink interference control threshold corresponding to the cell according to the downlink signal sampling data of the adjacent cells of the indoor cell; 3. The terminal in the indoor cell performs a power control judgment on the downlink transmission power. If the power control judgment result After determining that the downlink transmission power of the base station to the terminal will be greater than the downlink interference control threshold after the power control, the downlink transmission power of the terminal is adjusted to the downlink interference control threshold.

Therefore, when there are outdoor cells around the indoor cell, the downlink power received by the terminal in the indoor cell is controlled within a more appropriate range, reducing the interference of indoor communication to outdoor. The base station of the above-mentioned indoor cell may also be a distributed antenna system control device, a small base station, a repeater, or an AP. The above-mentioned power control judgment includes but is not limited to the existing open-loop power control judgment, closed-loop power control judgment, Judgment of the power of the inner ring and judgment of the power of the outer ring.

In this embodiment, the first and second parts are collectively referred to as the training downlink interference control threshold. The training of the downlink interference control threshold is usually performed before the system starts to provide normal services, for example, it can be performed during debugging after the base station is powered on and activated. In addition, a switch can be set for this part in the RNC to control the function of this part. When necessary, turn on the switch to start the training of the downlink interference control threshold. If the switch is not turned on, the downlink interference control threshold training function will not work. effect.

The first part - data sampling will be described first below. In this part, the detection terminal performs data sampling on the downlink signal of the adjacent cell in the indoor cell, and sends the sampled data to the base station of the indoor cell. Specifically, the detection terminal may perform data sampling near a window, a door, or other locations that are greatly interfered by outdoor cells. The sampled data includes the received signal code power (P _RSCP ) of the neighboring cell, and may also include the Ec/Io of the current cell and the neighboring cell.

Assuming that the indoor cell has n adjacent cells, the data sampled by the detection terminal is:

The indoor cell: (P _RSCP ) _local , (Ec/Io) _local ,

Adjacent cell 1: (P _RSCP ) ₁ , (Ec/Io) ₁

Neighboring cell 2: (P _RSCP ) ₂ , (Ec/Io) ₂

...

Adjacent cell n: (P _RSCP ) _n , (Ec/Io) _n

The detection terminal sends the sampling data to the base station of the indoor cell. It should be noted that in this step, the amount of sampled data can be selected according to the actual situation, as much as possible can be sampled, and it can also be appropriately reduced.

After obtaining the sampling data, enter the second part—the base station calculates the downlink interference control threshold according to the sampling data reported by the detection terminal. Specifically, the base station first calculates the average received signal code power according to the received signal code power of each adjacent cell, that is, ${\left(P_{\mathrm{RSCP}}\right)}_{\mathrm{AVG}}=\frac{1}{\mathrm{no}}\{\left(\mathrm{Prscp}\right)1+\left(\mathrm{Prscp}\right)2+...+\left(\mathrm{Prscp}\right)\mathrm{no}\};$ Next, the average received signal code power is added to the offset value to obtain the downlink interference control threshold P _{Thr — DL} corresponding to the cell. The offset value here is usually in the range of 5dB to 6dB. Assuming that 6dB is used in this embodiment, then P _{Thr_DL} =(P _RSCP ) _AVG +6dB.

This formula has two meanings. When the average received signal code power is greater than the received signal code power of the indoor cell, that is, (P _RSCP ) _AVG > (P _RSCP ) _local , the above formula is equivalent to P _{Thr_DL} = (P _RSCP ) _local + |(P _RSCP ) _local -(P _RSCP ) _AVG |+6dB, that is to say, first make up for the received signal code power of the cell, and then add 6dB when it reaches the average received signal code power, so that the base station is The transmit power of the indoor terminal is 6dB higher than the average received signal code power of the outdoor cell. At this time, the indoor interference to the outdoor is relatively small. When the average received signal code power is lower than the received signal code power of the local cell, that is, when (P _RSCP ) _AVG <(P _RSCP ) _local , P _{Thr_DL} = (P _RSCP ) _AVG +6dB, that is to say, directly connect the base station to the local indoor cell The downlink transmission power of the terminal is controlled within the range of the average received signal code power of the outdoor cell plus 6dB, so that the indoor interference to the outdoor is small.

Since the calculated downlink interference control threshold is independent for an indoor cell, the threshold corresponding to each indoor cell may be different according to the specific environment, so that the power control can be fully integrated with the environment, so as to improve the power control effect to the best.

After the downlink interference control threshold is calculated, enter the third part——perform downlink power control on the terminals residing in the indoor cell according to the threshold, as shown in FIG. 5 .

In step 510, according to the existing technology, according to the power control-related measurement values (such as SIR, received power of the terminal, etc.), the terminal residing in the indoor cell is judged on the power control of the downlink transmission power, including the existing open-loop , closed-loop power control, inner-loop power, and outer-loop power judgment.

In step 520, judge the current power control decision result, if the current power control decision result is to increase the downlink transmission power of the base station to the terminal, and the up-regulated downlink transmission power is greater than the downlink interference control threshold, then enter step 530 ; Conversely, if the current power control decision result is to lower the downlink transmit power of the base station to the terminal, or the power control decision result is to increase the downlink transmit power of the base station to the terminal, but the adjusted downlink transmit power is less than or equal to the downlink interference control threshold, go to step 540.

In step 530, the base station adjusts the downlink transmission power of the terminal to the downlink interference control threshold.

In step 540, the downlink transmission power of the base station to the terminal is adjusted according to the power control decision result.

Since the downlink interference control threshold is the average received signal code power plus 6dB, the downlink transmission power of the base station to the indoor cell terminal can only be greater than the average received downlink transmission power (ie, the average received signal code power) of the terminal in the outdoor cell According to the simulation results, it can be known that in this case, the indoor terminal can complete the communication, and the interference to the outdoor cell will be within a range of 1 meter from the indoor, so as to minimize the interference of the indoor cell communication to the outdoor cell.

Specifically, the following situations are included:

1. When the communicating terminal is located in an area close to the outdoors (such as windows, doors, balconies, etc.) within the coverage of the indoor cell, and the outdoor signal is good (that is, there are also terminals communicating in the outdoor cell), the base station will The downlink transmission power of indoor terminals is 6dB higher than the average downlink transmission power received by outdoor terminals. At this time, it can be guaranteed that for indoor terminals, the indoor cell is the dominant cell and will not affect their communication, and the difference of 6dB can Make sure that the signal leaking from indoor to outdoor is a weak interference signal and will not affect outdoor cells.

2. When the communicating terminal is in an indoor cell coverage area close to the outdoor area, and the outdoor signal is very weak, the maximum downlink transmission power of the base station to the indoor terminal is 6dB higher than the average downlink power received by the outdoor terminal. While ensuring the performance of users in indoor cells, the signal leakage to the outdoors is limited. According to the simulation, the influence of interference can be controlled within 1 meter from the indoor cells, and the service range of outdoor cells will not be significantly reduced.

3. When the communicating terminal is in the good coverage area of the indoor cell, its downlink transmission power is naturally small, and the indoor cell can directly control it according to the existing power control algorithm (that is, the result of the power control decision), and will not It causes interference to the outdoor network.

It can be seen that this implementation manner can ensure that the interference of indoor communication to outdoor cells is minimized in various scenarios.

It should be noted that the above-mentioned 6dB is just a specific example. In specific applications, since different scenarios allow different ranges of interference from indoor cells to outdoors, this 6dB can also be adjusted, for example, it can be adjusted to 5dB or 7dB etc.

The effect of this embodiment will be verified by using two examples below.

Example 1: In the case that there are communication signals in the outdoor network, calculate the interference of indoor communication on the outdoor network, that is, estimate the interference signal leaked out of the downlink.

According to the power control algorithm in this embodiment, the downlink signal leaked from the indoor cell minus the wall penetration loss and the loss in the propagation law of indoor and outdoor signals is the leaked interference signal. The law of wave propagation of indoor and outdoor signals, that is, the relationship between indoor and outdoor attenuation and distance, is shown in Figure 6. The specific values in Figure 6 correspond to Table 1.

R(m) L(dB, outdoor) L (dB, indoor) 0.1 -34.21602904 -7 1 -44.21602904 -37 2 -47.226329 -46.03089987 3 -48.98724159 -51.31363764 4 -50.23662895 -55.06179974 5 -51.20572908 -57.96910013 6 -51.99754154 -60.34453751 7 -52.66700944 -62.3529412 8 -53.24692891 -64.09269961 9 -53.75845413 -65.62727528 10 -54.21602904 -67

Table 1

The interference signal generated by indoor cell leakage can be described by the following formula:

Downlink interference signal = P _{Thr_DL} -L _penetration - L _space = P _{Thr_DL} -10-L _space , where P _{Thr_DL} is the maximum downlink transmission power of the base station to the indoor terminal, that is, the downlink interference control threshold; 10dB is the general wall penetration Penetration loss; L space is the loss of the signal in the law of indoor and outdoor wave propagation.

Next, according to the above formula, the interference of the communication in the indoor cell to the outdoor cell at a distance of 1 meter (m) from the indoor cell is calculated. Assuming that the communication terminal in the indoor cell is 2m away from the indoor antenna (in the boundary area connected to the outdoor), it can be seen from Table 1 that the attenuation in the law of wave propagation reaches 44.2dB when the outdoor is 1m away from the outer wall, and the indoor distance is 44.2dB. At 2m away from the indoor antenna, the attenuation in the wave propagation law reaches 46dB, and the wall loss is 10dB. The downlink interference control threshold of the indoor cell calculated according to this embodiment is generally 15dBm, and the antenna radiation efficiency is removed. The interference signal of the outdoor cell at a distance of 1m from the indoor cell=15dB-29dB (antenna radiation efficiency)-46dB (indoor attenuation)-44.2dB (outdoor attenuation)-10dB (wall loss)=-114.2dB, it can be seen that, Using this embodiment, when there are communication signals in the outdoor network, the indoor cell communication signal has less impact on the outdoor network.

Scenario 2: When there is no signal in the outdoor network, calculate the interference of indoor communication on the outdoor network, that is, estimate the interference signal leaked out of the downlink.

The above formula is also used to calculate the interference of the communication pair in the indoor cell at a distance of 1 meter from the indoor cell to the outdoor cell: downlink interference signal = P _{Thr_DL} - L _penetration - L _space . Among them, P _{Thr_DL} is the maximum transmission power of the base station to the indoor terminal, which is equal to the downlink interference control threshold in this embodiment, P _{Thr_DL} = (P _RSCP ) _AVG +6dB; the wall loss is also 10dB; According to Table 1, the loss in the outdoor wave propagation law is 44.2dB; assuming that the terminal communicating in the indoor cell is 2 meters away from the indoor antenna (in the boundary area connected with the outdoor), according to Table 1, the indoor wave propagation law is 44.2dB. The loss is 46dB. Thus you can get:

Downlink interference signal = (P _RSCP ) _AVG +6dB-46dB (indoor attenuation) -44.2dB (outdoor attenuation) -10dB (wall loss) = (P _RSCP ) _AVG -94.2dB.

Since there is no signal coverage outdoors at this time, the average received signal code power of the adjacent cell is 0, that is, (P _RSCP ) _AVG =0.

It can be seen that at 1M outdoors, the leakage output interference signal is -94.2dBm. Since the interference signal is small, there is no signal coverage outdoors, and the impact on the outdoors can be ignored. It can be seen that in this embodiment, the interference to the outdoor cell can be controlled within a range of 1 meter away from the indoor cell.

Since the attenuation is different, while the indoor base station interferes with the outdoor cell, the outdoor base station also interferes with the indoor cell. However, in general, the distance between the outdoor base station and the indoor cell is greater than 10 meters. Ensure that the indoor cell is the dominant cell, so the impact can be ignored.

The second embodiment of the present invention relates to an uplink power control method. As shown in FIG. 7 , in this embodiment, it also includes three parts: data sampling, calculation of uplink interference control threshold, and uplink power control based on the calculated threshold.

In this embodiment, the first and second parts are collectively referred to as the training uplink interference control threshold. The training of the uplink interference control threshold is usually performed before the system starts to provide normal services, for example, it can be performed during debugging after the base station is powered on and activated. A switch can be set for this part in the RNC to control the functions of this part. When necessary, turn on the switch to start the training of the uplink interference control threshold. If the switch is not turned on, the uplink interference control threshold training function will not work.

The first part - data sampling will be described first below. In this part, the detection terminal samples the uplink signal data in the indoor cell, and sends the sampled data to the base station of the indoor cell. Specifically, the detection terminal may perform data sampling near a window, a door, or other locations that are greatly interfered by outdoor cells. The sampled data includes detecting the actual uplink transmit power of the terminal at different locations in the indoor cell.

Assume that the detection terminal has sampled n actual uplink transmission power values at m positions respectively:

P _{TX_UE(1,1)} ,P _{TX_UE(1,2)} ......P _{TX_UE(1,n)}

P _{TX_UE(2, 1)} , P _{TX_UE(2, 2)} ... P _{TX_UE(2, n))}

...

P _{TX_UE(m, 1)} , P _{TX_UE(m, 2)} ......P _{TX_UE(m, n)}

The detection terminal sends the sampling data to the base station of the indoor cell.

After obtaining the sampling data, enter the second part—the base station calculates the uplink interference control threshold according to the received sampling data. Specifically, the base station calculates the average uplink transmit power of the terminal based on at least two actual uplink transmit powers in at least two locations reported by the detected terminal, and uses the average uplink transmit power as the uplink interference control threshold corresponding to the cell, that is $P_{\mathrm{Thr}\_\mathrm{UL}}={\stackrel{\&OverBar;}{P}}_{\mathrm{TX}\_\mathrm{UE}}=\frac{1}{m\&times;N}\underset{1}{\overset{m}{\mathrm{\&Sigma;}}}\underset{1}{\overset{N}{\mathrm{\&Sigma;}}}\left(P_{\mathrm{TX}\_\mathrm{UE}}(m,\mathrm{no})\right).$ That is to say, the maximum uplink transmit power of an indoor terminal is the indoor average uplink transmit power. Since a terminal in an indoor cell uses the average uplink transmit power, it can maintain normal communication with the base station, and the interference to the outdoor cell is small at this time. While ensuring the normal communication of the terminal in the indoor cell, the interference of the indoor cell to the outdoor cell is negligible.

In addition, since the calculated uplink interference control threshold is independently for an indoor cell, the threshold corresponding to each indoor cell may be different according to the specific environment, so that the power control can be fully integrated with the environment, so as to maximize the effect of power control. good.

After the uplink interference control threshold is calculated, enter the third part——perform uplink power control on the terminals residing in the indoor cell according to the threshold, as shown in FIG. 8 .

In step 810, according to the existing technology, according to the power control-related measurement values (such as SIR, received power of the terminal, etc.), the terminal residing in the indoor cell is judged on the power control of the uplink transmit power, including the existing open-loop , closed-loop power control, inner-loop power, and outer-loop power judgment.

In step 820, judge the current power control decision result, if the current power control decision result is to increase the uplink transmission power of the terminal, and the uplink transmission power after the increase is greater than the uplink interference control threshold, then enter step 830; otherwise , if the current power control decision result is to lower the uplink transmission power of the terminal, or if the power control decision result is to increase the uplink transmission power of the terminal, but the uplink transmission power after the adjustment is less than or equal to the uplink interference control threshold, then enter the step 840.

In step 830, the terminal is instructed to adjust its uplink transmission power to the uplink interference control threshold. Therefore, in the case that there are outdoor cells around the indoor cell, the communication power of the terminal in the indoor cell can be controlled within a more appropriate range, and the interference of indoor communication to the outdoors can be reduced. Moreover, since the terminal in the indoor cell can maintain normal communication with the base station using the average uplink transmission power, the interference to the outdoor cell is reduced without affecting the communication of the terminal in the cell.

In step 840, the terminal is instructed to adjust its uplink transmit power according to the power control decision result.

An example is used below to verify the effect of this embodiment.

The indoor uplink signal leakage to the outdoor is caused by the actual uplink transmission power of the terminal, that is, the uplink transmission signal of the terminal in the indoor cell minus the coupling loss is the leaked uplink interference signal. According to the power control algorithm of this embodiment, the maximum transmission signal of the terminal is P _{Thr_UL} , and according to experience, P _{Thr_UL} is usually equal to 7dB, and in general, the location coupling loss from the outdoor cell to the indoor coverage system is 133dB, so the estimation of the uplink interference signal as follows:

Uplink interference signal = 7dB-133dB = -126dBm;

It can be seen that, using the present embodiment to perform uplink power control, the uplink communication signal of the indoor cell has little impact on the outdoor network, which can be ignored.

The third embodiment of the present invention relates to a downlink power control system, as shown in FIG. 9 , including: a calculation unit, configured to calculate the downlink interference control threshold corresponding to the indoor cell according to the downlink signal sampling data of the adjacent cell of the indoor cell The power control unit is used to perform power control judgment and power adjustment of the downlink transmission power of the terminal in the indoor cell; the judgment unit is used to judge the network side after power control according to the power control judgment result of the power control unit. Whether the downlink transmission power of the terminal will be greater than the downlink interference control threshold, if so, instruct the power control unit to adjust the downlink transmission power of the terminal to the downlink interference control threshold. Therefore, the downlink power received by the terminal in the indoor cell is controlled within a more suitable range, and the interference of indoor communication to outdoor is reduced. In addition, since the calculated downlink interference control threshold is independently for an indoor cell, the threshold corresponding to each indoor cell may be different according to the specific environment, so that the power control can be fully integrated with the environment, so as to maximize the effect of power control. good.

The judging unit is also used to, according to the power control judgment result of the power control unit, when it is determined that the downlink transmission power of the terminal on the network side after power control will be less than or equal to the downlink interference control threshold, instruct the power control unit to The power control decision result adjusts the downlink transmission power of the terminal on the network side.

Wherein, the sampled data is obtained by sampling at the position where the indoor cell overlaps with the adjacent cell (that is, the position in the indoor cell that is greatly affected by the outdoor neighbor cell), and the sampled data includes at least the received signal code of the adjacent cell Power, the calculation unit includes the following subunits:

The averaging subunit is used to calculate the average received signal code power according to at least one received signal code power of at least one adjacent cell; the interference control threshold calculation subunit is used to add a bias value to the average received signal code power to obtain The downlink interference control threshold corresponding to the indoor cell. The offset value ranges from 5dB to 6dB. Since the downlink power transmitted by the base station to the terminal in the indoor cell can exceed the offset value of the average received signal code power outdoors, even if the signal of the adjacent outdoor cell is strong, the interference to the indoor cell is relatively large, and the user is in the indoor cell. In areas with serious interference, it can also ensure that indoor communication can be carried out normally; in addition, no matter whether the outdoor signal is strong or not, the downlink power transmitted by the base station to users in indoor cells can only exceed the offset value at most when the user communicates in the indoor cell. (such as 5dB or 6dB), so that the downlink power received by the terminal in the indoor cell can be controlled within a more suitable range, so that the interference from indoor communication to the outdoor is within a range closer to the indoor (such as 1 meter), Minimize the interference of indoor cell communication to outdoor cells.

The fourth embodiment of the present invention relates to an uplink power control system, as shown in FIG. 10 , including: a calculation unit, configured to calculate the uplink interference control threshold corresponding to the indoor cell according to the uplink signal sampling data of the indoor cell; a power receiving unit , used to receive the actual uplink transmit power of the terminal reported by the terminal in the indoor cell; the power control unit is used to perform power control judgment and power adjustment of the uplink transmit power of the terminal in the indoor cell; the judgment unit is used to judge according to Based on the judgment result of the power control unit and the actual uplink transmission power of the terminal received by the power receiving unit, it is judged whether the actual uplink transmission power of the terminal after power control will be greater than the uplink interference control threshold, and if it is greater, it will instruct the power control unit to The actual uplink transmit power of the terminal is adjusted to the uplink interference control threshold. Therefore, when there are outdoor neighbor cells around the indoor cell, the uplink transmit power of the terminal in the indoor cell can be controlled within a more appropriate range, reducing the interference of indoor communication to outdoor. In addition, since the calculated uplink interference control threshold is independently for an indoor cell, the threshold corresponding to each indoor cell may be different according to the specific environment, so that the power control can be fully integrated with the environment, so as to maximize the effect of power control. good.

The sampled data is obtained by sampling at the position where the indoor cell overlaps with the adjacent cell (that is, the position in the indoor cell that is greatly affected by the outdoor neighbor cell), and the sampled data includes at least two At least two actual uplink transmission powers in two different locations, the calculation unit calculates the uplink interference control threshold by: calculating the average uplink transmission power of the terminal according to the at least two actual uplink transmission powers in the at least two locations, the indoor The uplink interference control threshold corresponding to the cell is equal to the average uplink transmit power. Since the terminals in the indoor cell can maintain normal communication with the base station using the average uplink transmission power, and at this time, the interference to the outdoor cell is small, so that while ensuring the normal communication of the indoor cell terminal, the indoor cell interferes with the outdoor cell can be ignored.

To sum up, in the embodiment of the present invention, the downlink interference control threshold corresponding to the indoor cell is calculated according to the downlink signal sampling data of the adjacent cells of the indoor cell; If it is determined according to the power control decision result that the downlink transmit power of the terminal on the network side will be greater than the downlink interference control threshold, the downlink transmit power of the terminal will not be adjusted according to the decision result, but the downlink transmit power of the terminal will be adjusted to The downlink interference control threshold. Therefore, when there are outdoor neighboring cells around the indoor cell, the downlink power received by the terminal in the indoor cell can be controlled within a more appropriate range, reducing the interference of indoor communication to outdoors. In addition, since the calculated downlink interference control threshold is independently for an indoor cell, the threshold corresponding to each indoor cell may be different according to the specific environment, so that the power control can be fully integrated with the environment, so as to maximize the effect of power control. good.

According to the uplink signal sampling data of the indoor cell, calculate the uplink interference control threshold corresponding to the indoor cell; the terminal in the indoor cell reports its actual uplink transmit power, and after making the power control decision on the uplink transmit power of the terminal in the indoor cell, if According to the power control judgment result, it is determined that the actual uplink transmission power of the terminal will be greater than the uplink interference control threshold after power control, and then the actual uplink transmission power of the terminal is adjusted to the uplink interference control threshold without performing power adjustment according to the judgment result. Therefore, when there are outdoor neighbor cells around the indoor cell, the uplink transmit power of the terminal in the indoor cell can be controlled within a more appropriate range, reducing the interference of indoor communication to outdoor. In addition, since the calculated uplink interference control threshold is independently for an indoor cell, the threshold corresponding to each indoor cell may be different according to the specific environment, so that the power control can be fully integrated with the environment, so as to maximize the effect of power control. good.

The signal data sampling can be performed in the indoor cell where the outdoor signal interference is strong, so as to ensure the calculated uplink and/or downlink interference control threshold, which can be applied to both the terminal in the good signal area of the indoor cell and the terminal in the signal interference area. terminal in the area.

The downlink interference control threshold is equal to: the average received signal code power of at least one received signal code power of each adjacent cell plus an offset value, the offset value can be obtained based on experience or anti-true results, and can be 6dB. Since the downlink power transmitted by the base station to the terminal in the indoor cell can exceed the offset value of the average received signal code power outdoors, even if the signal of the adjacent outdoor cell is strong, the interference to the indoor cell is relatively large, and the user is in the indoor cell. In areas with serious interference, it can also ensure that indoor communication can be carried out normally; in addition, no matter whether the outdoor signal is strong or not, the downlink power transmitted by the base station to users in indoor cells can only exceed the offset value at most when the user communicates in the indoor cell. (such as 5dB or 6dB), so that the downlink power received by the terminal in the indoor cell can be controlled within a more suitable range. According to experience or simulation, it can be determined that the interference from indoor communication to outdoor is closer to the indoor ( For example, within a range of 1 meter), the interference of indoor cell communication to outdoor cells is minimized.

The uplink interference control threshold is equal to the average uplink transmit power of each sampling location, that is, the maximum uplink transmit power of an indoor terminal is the indoor average uplink transmit power, because the terminal in an indoor cell can maintain normal communication with the base station using the average uplink transmit power, and this The interference to the outdoor cell is small, so that while ensuring the normal communication of the terminal in the indoor cell, the impact of the indoor cell on the outdoor cell can be ignored.

Although the present invention has been illustrated and described with reference to certain preferred embodiments thereof, those skilled in the art will recognize that various changes in form and details may be made therein without departing from the present invention. The spirit and scope of the invention.

Claims (5)

1. an ascending power control method is characterized in that, may further comprise the steps:

Upward signal sampled data according to indoor cell; Calculate the corresponding uplink interference control thresholding of this indoor cell; Said sampled data comprises locational at least two the actual uplink transmitting powers of at least two of said indoor cell; Said calculating uplink interference control thresholding specifically comprises; The base station is controlled thresholding with said average uplink transmission power as the corresponding uplink interference in said sub-district according to the average uplink transmission power of said at least two locational at least two actual uplink transmitting power computing terminals;

Receive the actual uplink transmitting power at this terminal of terminal to report in the said indoor cell;

The terminal in the said indoor cell is carried out the power control judgement of uplink transmission power according to the power control correlation measure; If the actual uplink transmitting power of confirming said terminal after the power control according to the power control court verdict is then adjusted to this uplink interference control thresholding with the actual uplink transmitting power at this terminal greater than said uplink interference control thresholding.

2. ascending power control method according to claim 1; It is characterized in that; If confirm that according to said power control court verdict the actual uplink transmitting power at said terminal is less than or equal to said uplink interference control thresholding after the power control, then according to the uplink transmission power at this this terminal of power control court verdict adjustment.

3. ascending power control method according to claim 1 is characterized in that, said sampled data in said indoor cell, overlaps with neighbor cell or the position adjacent up-sampling obtains;

It is one of following that said position comprises at least: in the preset range of indoor cell doorway, in the indoor cell window preset range.

4. a uplink power control system is characterized in that, comprising:

Computing unit; Be used for upward signal sampled data according to indoor cell; Calculate the corresponding uplink interference control thresholding of this indoor cell; Said sampled data comprises locational at least two the actual uplink transmitting powers of at least two of said indoor cell; The mode that said computing unit calculates uplink interference control thresholding is: according to said at least two locational at least two actual uplink transmitting powers, and the average uplink transmission power of computing terminal, the corresponding uplink interference control thresholding of said indoor cell equals this average uplink transmission power;

The power receiving element is used to receive the actual uplink transmitting power at this terminal of terminal to report in the said indoor cell;

The power control unit is used for according to the power control correlation measure terminal in the said indoor cell being carried out the power control judgement and the power adjustment of uplink transmission power;

Judging unit; The actual uplink transmitting power at the said terminal that is used for receiving according to the court verdict and the said power receiving element of said power control unit; Whether the actual uplink transmitting power of judging said terminal after the power control greater than said uplink interference control thresholding, if greater than would indicate said power control unit that the actual uplink transmitting power at this terminal is adjusted to this uplink interference control thresholding.

5. uplink power control according to claim 4 system is characterized in that, said sampled data in said indoor cell, overlaps with neighbor cell or the position adjacent up-sampling obtains.

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