CN102088759B

CN102088759B - Downlink power control system and method

Info

Publication number: CN102088759B
Application number: CN200910225577.1A
Authority: CN
Inventors: 姜静; 孙云锋; 张峻峰
Original assignee: ZTE Corp
Current assignee: ZTE Corp
Priority date: 2009-12-03
Filing date: 2009-12-03
Publication date: 2015-05-20
Anticipated expiration: 2029-12-03
Also published as: CN102088759A

Abstract

The invention provides a downlink power control system and a downlink power control method. The method comprises the following steps that: a base station sets average power of resource elements on an orthogonal frequency division multiplexing sign; and the base station informs a ratio of the power of each resource element of the orthogonal frequency division multiplexing sign which comprises a channel measurement pilot frequency to the power of each resource element of the orthogonal frequency division multiplexing sign which does not comprises the channel measurement pilot frequency to the terminal after the power control by using signaling. By the method, the quality of channel estimation of the channel measurement pilot frequency can be guaranteed by keeping the same sending power of the channel measurement pilot frequency and the public pilot frequency of long term evolution (LTE); furthermore, by the method, the average power of the resource data can be amplified to pass the signal quality of cell edge users; meanwhile, the execution method of downlink power control in the LTE standard is kept; and in the absence of extra signaling, the power control process is simply realized.

Description

A kind of system and method for downlink power control

Technical field

The present invention relates to wireless communication system, specifically, be particularly useful for the system and method for a kind of downlink power control under LTE-Advanced (LTE of evolution) system.

Background technology

Two kinds of pilot tones of LTE-Advanced have been defined: channel measurement pilot frequency (hereinafter referred to as CSI-RS) and demodulation pilot frequency (hereinafter referred to as DMRS) in 3GPP LTE56 meeting, wherein clear and definite channel measurement pilot frequency is cell-specific (cell-specific), distributes more sparse relative to demodulation pilot frequency on running time-frequency resource.And the foundation that channel measurement pilot frequency obtains as schedule information, by decision systems CQI (channel quality information), the value of PMI (precoding information) and RI (order), largely determine the performance of system, therefore need to carry out power amplification to channel measurement pilot frequency, to improve the channel estimation quality of channel measurement pilot frequency, reduce the interference of other cell datas to channel measurement pilot frequency.

Summary of the invention

The technical problem to be solved in the present invention is to provide a kind of system and method for downlink power control, can keep the quality of CSI-RS channel estimating.

In order to solve the problem, the invention provides a kind of method for controlling downlink power, comprise: base station sets resource element average power on OFDM symbol, the power ratio of each resource element of the power comprising each resource element of OFDM symbol of channel measurement pilot frequency after described this power of base station employing signaling terminal control afterwards and the OFDM symbol not comprising channel measurement pilot frequency.

Further, the transmitting power of each resource element of the data channel on the OFDM symbol at signaling channel measurement pilot frequency place is B, do not have the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency to be A, the power of each resource element of the OFDM symbol comprising channel measurement pilot frequency described in terminal and the power ratio of each resource element of OFDM symbol not comprising channel measurement pilot frequency are informed by feeding back the ratio of B/A in base station.

Further, described base station sets resource element average power on OFDM symbol in the following manner, if channel measurement pilot frequency place OFDM symbol comprises the resource element of N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is reduced to n-i by base station, and be evenly distributed to by described power n-i on the resource element of described N number of transmission data, and the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency is not had to remain unchanged;

Described B/A=(n-i)/n after setting.

Further, described base station sets resource element average power on OFDM symbol in the following manner, if channel measurement pilot frequency place symbol comprises the resource element of N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is enlarged into n+j by base station, and be evenly distributed to by described power n+j on the resource element of described N number of transmission data, and the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency is not had to remain unchanged;

Described B/A=(n+j)/n after setting.

Further, m kind power control mode is preset in base station, and be often kind of mode serial number, when adopt wherein a kind of mode time, base station adopts this power of signaling terminal to control the numbering of corresponding mode, and terminal knows the value of described B/A under the mode that this power controls and which according to described numbering.

Further, the value of described m is 4, the mode that described base station adopts 2 these power of bit signalling notification terminal to control.

The present invention also provides a kind of down power controlling system, comprises base station and terminal;

Described base station comprises power control module and notification module;

Described power control module, for setting resource element average power on OFDM symbol;

Described notification module, the power ratio of each resource element of the power comprising each resource element of OFDM symbol of channel measurement pilot frequency after controlling for adopting this power of terminal described in signaling and the OFDM symbol not comprising channel measurement pilot frequency.

Further, the transmitting power of each resource element of the data channel on the OFDM symbol at signaling channel measurement pilot frequency place is B, do not have the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency to be A, described notification module is by the power that comprises each resource element of OFDM symbol of channel measurement pilot frequency described in the ratio notification terminal of feedback B/A and the power ratio of each resource element of OFDM symbol not comprising channel measurement pilot frequency.

Further, on described power control module setting OFDM symbol, resource element average power refers to, if channel measurement pilot frequency place OFDM symbol comprises the resource element of N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is reduced to n-i by power control module, and be evenly distributed to by described power n-i on the resource element of described N number of transmission data, and the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency is not had to remain unchanged;

Described B/A=(n-i)/n after setting.

Further, on described power control module setting OFDM symbol, resource element average power refers to, if channel measurement pilot frequency place symbol comprises the resource element of N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is enlarged into n+j by power control module, and be evenly distributed to by described power n+j on the resource element of described N number of transmission data, and the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency is not had to remain unchanged;

Described B/A=(n+j)/n after setting.

Further, power control module presets m kind power control mode, and be often kind of mode serial number, when adopt wherein a kind of mode time, notification module adopts this power of signaling terminal to control the numbering of corresponding mode, and terminal knows the value of described B/A under the mode that this power controls and which according to described numbering.

Further, the value of described m is 4, the mode that described notification module adopts 2 these power of bit signalling notification terminal to control.

In sum, the invention provides a kind of system and method for downlink power control, by keeping the public guide frequency (CRS) of CSI-RS with LTE to adopt the same transmitted power, to realize the quality ensureing CSI-RS channel estimating.In addition, can also be amplified the average power of resource data by the present invention, have passed the signal quality of Cell Edge User.And the present invention maintains the manner of execution of downlink power control in LTE standard, without the need to extra signaling, power control process realizes simple.

Accompanying drawing explanation

Fig. 1 is present system structural representation;

Fig. 2 is the schematic diagram of downlink power control embodiment one of the present invention;

Fig. 3 is the schematic diagram of downlink power control embodiment two of the present invention;

Fig. 4 is the schematic diagram of downlink power control embodiment three of the present invention;

Fig. 5 a is the channel measurement pilot frequency schematic diagram of an antenna port in downlink power control embodiment four of the present invention;

Fig. 5 b is the channel measurement pilot frequency schematic diagram of two, four, eight antenna ports in downlink power control embodiment four of the present invention.

Embodiment

The present invention proposes a kind of system and method for downlink power control, can keep the quality of CSI-RS channel estimating.

The present embodiment provides a kind of system of downlink power control, and as shown in Figure 1, this system comprises base station and terminal;

Base station comprises power control module and notification module;

Power control module, for setting RE in OFDM symbol (resource element) average power;

Notification module, the power ratio of each RE of the power comprising each RE of OFDM symbol of CSI-RS after controlling for adopting this power of signaling terminal and the OFDM symbol not comprising CSI-RS.

If

And make the transmitting power of each RE of the data channel in the OFDM symbol at CSI-RS place be B, namely the average power sending the RE of CSI-RS is B, do not have the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS to be A, the average power namely sending the RE of data is A;

Therefore,

P_{B} = \frac{ρ_{B}}{ρ_{A}} = B / A;

In formula, EPRE (Energy per Resource Element) is the power of each RE, and cell-specific is that community is all, and the pilot tone of cell-specific comprises such as public guide frequency, channel measurement pilot frequency.P _bfor power control module carry out power control after the power comprising each RE of OFDM symbol of CSI-RS and the power ratio of each RE of OFDM symbol not comprising CSI-RS.

The power comprising each resource element of OFDM symbol of CSI-RS after the control of this power of notification module notification terminal and the power ratio of each RE of the OFDM symbol not comprising CSI-RS notify that power controls the value of rear B/A.

If channel measurement pilot frequency comprises the RE of N number of transmission data on the ofdm symbols, and the gross power of this N number of resource element is n;

In power control module setting OFDM symbol, RE average power refers to, the gross power of N number of resource element is reduced to n-i by power control module, and power n-i is evenly distributed on the resource element of N number of transmission data, and do not have the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS to remain unchanged, now B/A=(n-i)/n.

Power control module can be directly the power of the RE of each transmission data is reduced into original (n-i)/n, can also be destroy I the power sending the RE of data (gross power that this I RE is corresponding is i), and is evenly distributed on the RE of N number of transmission data by the power (i.e. n-i) of RE of remaining N-I transmission data.

In power control module setting OFDM symbol, RE average power refers to, the gross power of N number of resource element is enlarged into n+j by power control module, and power n+j is evenly distributed on the RE of N number of transmission data, and do not have the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS to remain unchanged, now B/A=(n+j)/n.

Power control module can be direct is original (n+j)/n by the power amplification of the RE of each transmission data, can also be destroy J the power of RE sending CSI-RS (gross power that this J RE is corresponding is j), and is assigned to by the power averaging of this J RE on the RE of N number of transmission data.

Power control module can preset m kind power control mode, and be often kind of mode serial number, when adopt wherein a kind of mode time, notification module adopts this power of signaling terminal to control the numbering of corresponding mode, and terminal knows the value of B/A under the mode that this power controls and which according to this numbering.

The present embodiment provides a kind of method for controlling downlink power, base station sets RE average power in OFDM symbol, the power ratio of each RE of the power comprising each resource element of OFDM symbol of CSI-RS after this power of the signaling of base station employing afterwards terminal controls and the OFDM symbol not comprising CSI-RS.

First UE (terminal) supposes that all pilot tone in community adopts constant transmitting power, until receive all pilot power information in community on whole downlink bandwidth and any subframe.The received power of each RE of descending pilot frequency is informed by high level.Down transmitting power is defined as the performance number of all pilot tones in all communities on bandwidth of operation.Therefore define

And

And the transmitting power making each RE of the data channel in the OFDM symbol at CSI-RS place is B, the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS is not had to be A;

Therefore,

P_{B} = \frac{ρ_{B}}{ρ_{A}} = B / A;

In formula, EPRE (Energy per Resource Element) is the power of each RE, and cell-specific is that community is all, and the pilot tone of cell-specific comprises such as public guide frequency, channel measurement pilot frequency.

Step 101: base station sets RE average power in OFDM symbol, and keep the power of CSI-RS consistent with the transmitting power of the CRS of LTE.

If CSI-RS comprises the RE of N number of transmission data on the ofdm symbols, and the gross power of this N number of RE is n; Base station can set RE average power in OFDM symbol in the following ways:

A () base station reduces the average power that CSI-RS sends the RE of data on the ofdm symbols, gross power by N number of RE is reduced to n-i, and power n-i is evenly distributed on the RE of N number of transmission data, and do not have the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS to remain unchanged, then B/A=(n-i)/n.

Particularly, base station can be directly the power of the RE of each transmission data is reduced into original (n-i)/n, can also be destroy I the power sending the RE of data (gross power that this I RE is corresponding is i), and is evenly distributed on the RE of N number of transmission data by the power (i.e. n-i) of RE of remaining N-I transmission data.

B the average power that CSI-RS sends the RE of data is on the ofdm symbols amplified in () base station, gross power by N number of RE is enlarged into n+j, and power n+j is evenly distributed on the RE of N number of transmission data, and do not have the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS to remain unchanged, then B/A=(n+j)/n.

Particularly, base station can be direct is original (n+j)/n by the power amplification of the RE of each transmission data, can also be destroy J the power of RE sending CSI-RS (gross power that this J RE is corresponding is j), and is assigned to by the power averaging of this J RE on the RE of N number of transmission data.

Step 102: the value of B/A after base station adopts this power of signaling UE to control;

Particularly, when base station notice UE power controls the value of rear B/A, it can be the value adopting signaling B/A, it can also be default m kind power control mode, and be often kind of mode serial number, when adopt wherein a kind of mode time, base station adopts this power of signaling UE to control the numbering of corresponding mode, and UE knows the value of B/A under the mode that this power controls and which according to numbering.

The present invention is further illustrated below by way of several application example

Application example one:

CSI-RS with CRS adopts the same power, and the power of CSI-RS remains unchanged, and can carry out power amplification to data channel or reduce.The ratio of the power method of data channel specifies as follows:

P _B	The RE quantity of destroying	Four antenna ports	Eight antenna ports
				0	0	1	1
1	1	3/4	3/4
				2	2	1/2	1/2
3	3	1/4	1/4

As shown in Figure 2, N=4 in this embodiment, then there are 8 CSI-RS, reduce the power of the RE sending data, and keep not having the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS constant, mode can be that (gross power of I RE is i), and divided equally by the power of remaining RE on this N number of RE, then the value of B/A is (n-i)/n for power by destroying I RE; As shown in table 1, if I=1, then the value of B/A is 3/4, if I=2, then the value of B/A is 1/2, if I=3, then the value of B/A is 1/4;

Afterwards, base station adopts signaling UE to carry out power and controls the rear change sending the RE power of data, particularly, the mode that several power controls is preset in base station, and be numbered for often kind of mode, when adopt wherein certain mode time, the numbering corresponding to mode of the power control directly adopting bit signalling notice UE to adopt; In the present embodiment, if adopt 4 kinds of modes altogether, mode 1 correspondence is not to the situation that the power of RE carries out mode or reduces, the value of the corresponding B/A of mode 2 is 3/4, its implementation can be, but not limited to be the power destroying 1 RE, and the value of the corresponding B/A of mode 3 is 1/2, and the value of the corresponding B/A of mode 4 is 1/4; Therefore, base station can adopt 2 these power of bit notification UE to control corresponding mode, mode 1 corresponding bit signaling 00, mode 2 corresponding bit signaling 01, mode 3 corresponding bit signaling 10, mode 4 corresponding bit signaling 11.

Application example two:

CSI-RS with CRS adopts the same power, can carry out power amplification to data channel or reduce.

Table 2: the power control mode of embodiment two

P _B

The RE quantity of destroying

Four CSI-RS antenna ports

Eight CSI-RS antenna ports

0	0	1	1
				1	2	3/4	3/4
2	3	5/8	5/8
				3	4	1/2	1/2

As shown in Figure 3, the present embodiment N=8, then there are 4 CSI-RS, reduce the power of the RE sending data, and keeping not having the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS constant, mode can be directly reduce the power of each RE, can also be that (gross power of I RE is i) for power by destroying I RE, divided equally by the power of remaining RE on this n RE, then the value of B/A is (n-i)/n; As shown in table 2, if I=2, then the value of B/A is 3/4, if I=3, then the value of B/A is 5/8, if I=4, then the value of B/A is 1/2;

Afterwards, base station adopts signaling UE to carry out the value of the rear B/A of power control, particularly, the mode that m kind power controls is preset in base station, and be numbered for often kind of mode, when adopt wherein certain mode time, the numbering corresponding to mode of the power control directly adopting bit signalling notice UE to adopt; In the present embodiment, if adopt 4 kinds of modes altogether, mode 1 correspondence is not to the situation that the power of RE carries out mode or reduces, namely the value of B/A is 1, the value of the corresponding B/A of mode 2 is 3/4, its implementation can be, but not limited to be the power destroying 2 RE, and the value of the corresponding B/A of mode 3 is 5/8, and the value of the corresponding B/A of mode 4 is 1/2; Therefore, base station can only adopt 2 these power of bit notification UE to control corresponding mode, mode 1 corresponding bit signaling 00, mode 2 corresponding bit signaling 01, mode 3 corresponding bit signaling 10, mode 4 corresponding bit signaling 11.

Application example three:

Table 3: the power control mode of embodiment three

P _B	The RE quantity of destroying	Four or eight CSI-RS antenna ports
			0	0	1
1	2	4/5

2	4	3/5
			3	6	2/5

As shown in Figure 4, N=10 in the present embodiment, then there are 2 CSI-RS, reduce the power of the RE sending data, and keeping not having the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS constant, mode can be directly reduce the power of each RE, can also be that (gross power of I RE is i) for the power of RE by destroying I transmission data, divided equally by the power of the RE of remaining transmission data on this n RE, then the value of B/A is (n-i)/n; As shown in table 3, if I=2, then the value of B/A is 4/5, if I=4, then the value of B/A is 3/5, if I=6, then the value of B/A is 2/5;

Afterwards, base station adopts signaling UE to carry out the value of the rear B/A of power control, particularly, the mode that m kind power controls is preset in base station, and be numbered for often kind of mode, when adopt wherein certain mode time, the numbering corresponding to mode of the power control directly adopting bit signalling notice UE to adopt; In the present embodiment, if adopt 4 kinds of modes altogether, mode 1 correspondence is not to the situation that the power of RE carries out mode or reduces, namely the value of B/A is 1, the value of the corresponding B/A of mode 2 is 4/5, its implementation can be, but not limited to be the power destroying 2 RE, and the value of the corresponding B/A of mode 3 is 3/5, and the value of the corresponding B/A of mode 4 is 2/5; Therefore, base station can only adopt 2 these power of bit notification UE to control corresponding mode, mode 1 corresponding bit signaling 00, mode 2 corresponding bit signaling 01, mode 3 corresponding bit signaling 10, mode 4 corresponding bit signaling 11.

Application example four:

Table 4: the power control mode of embodiment four

P _B	An antenna port	Two, four or eight antenna ports
			0	1	5/4
1	4/5	1
			2	3/5	3/4
3	2/5	1/2

When a channel measurement pilot frequency is antenna port, as shown in Figure 5 a, N=10, then there are 2 CSI-RS, reduce the power of the RE sending data, and keep not having the transmitting power of each RE of data channel in the OFDM symbol of CSI-RS constant, mode can be the power of the RE directly reducing each transmission data, can also be that (gross power of I RE is i) by destroying I the power of RE sending data, divided equally by the power of the RE of remaining transmission data on this n RE, then the value of B/A is (n-i)/n; As shown in table 4, if I=2, then the value of B/A is 4/5, if I=4, then the value of B/A is 3/5, if I=6, then the value of B/A is 2/5;

When channel measurement is two, four or eight antenna ports time, as shown in Figure 5 b, CSI-RS takies 4 RE in each OFDM symbol, when reduction CSI-RS transmitting power (is equivalent to the power destroying 2 CSI-RS RE, and the power averaging of this CSI-RS is assigned on each RE), the power now sending the RE of data becomes original 5/4, namely the value of B/A is 5/4, when data and CSI-RS constant power, power amplification coefficient power amplification ratio is 1, namely the value of B/A is 1, when destroying the power that 2 send the RE of data, and the power remaining 6 being sent the RE of data is divided equally on these 8 RE sending data, then the value of B/A is 3/4, when destroying the data RE that 4 send data, and the power of 4 RE of remaining transmission data is divided equally on these 8 RE sending data, then the value of B/A is 1/2.In the present embodiment, if adopt 4 kinds of modes altogether, the value of the corresponding B/A of mode 1 is 5/4, and mode 2 correspondence does not zoom in or out the average power of RE, and the value of the corresponding B/A of mode 3 is 3/4, and the value of the corresponding B/A of mode 4 is 1/2; Therefore, base station can only adopt 2 these power of bit notification UE to control corresponding mode, mode 1 corresponding bit signaling 00, mode 2 corresponding bit signaling 01, mode 3 corresponding bit signaling 10, mode 4 corresponding bit signaling 11.

Claims

1. a method for controlling downlink power, comprise: base station sets resource element average power on OFDM symbol, the power ratio of each resource element of the power comprising each resource element of OFDM symbol of channel measurement pilot frequency after described this power of base station employing signaling terminal control afterwards and the OFDM symbol not comprising channel measurement pilot frequency;

Wherein, the power comprising each resource element of OFDM symbol of channel measurement pilot frequency after the control of described this power of base station employing signaling terminal refers to the power ratio of each resource element of the OFDM symbol not comprising channel measurement pilot frequency:

The transmitting power of each resource element of the data channel on the OFDM symbol at signaling channel measurement pilot frequency place is B, do not have the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency to be A, the power of each resource element of the OFDM symbol comprising channel measurement pilot frequency described in terminal and the power ratio of each resource element of OFDM symbol not comprising channel measurement pilot frequency are informed by feeding back the ratio of B/A in base station;

Described base station sets resource element average power on OFDM symbol in the following manner: establish resource element channel measurement pilot frequency place OFDM symbol comprising N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is reduced to n-i by base station, and described power n-i is evenly distributed on the resource element of described N number of transmission data, and do not have the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency to remain unchanged, described B/A=(n-i)/n after setting, i is the decrease of the gross power of described N number of resource element.

2. the method for claim 1, is characterized in that:

Described base station sets resource element average power on OFDM symbol in the following manner, if channel measurement pilot frequency place symbol comprises the resource element of N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is enlarged into n ﹢ j by base station, and be evenly distributed on the resource element of described N number of transmission data by described power n ﹢ j, and the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency is not had to remain unchanged;

After setting, described B/A=(n ﹢ j)/n, j are the recruitment of the gross power of described N number of resource element.

3. the method described in claim 1 or 2, is characterized in that:

M kind power control mode is preset in base station, and be often kind of mode serial number, when adopt wherein a kind of mode time, base station adopts this power of signaling terminal to control the numbering of corresponding mode, and terminal knows the value of described B/A under the mode that this power controls and which according to described numbering.

4. method as claimed in claim 3, is characterized in that:

The value of described m is 4, the mode that described base station adopts 2 these power of bit signalling notification terminal to control.

5. a down power controlling system, comprises base station and terminal; It is characterized in that:

Described base station comprises power control module and notification module;

Described notification module, the power ratio of each resource element of the power comprising each resource element of OFDM symbol of channel measurement pilot frequency after controlling for adopting this power of terminal described in signaling and the OFDM symbol not comprising channel measurement pilot frequency;

Wherein, described notification module refers to for the power that comprises each resource element of OFDM symbol of channel measurement pilot frequency after adopting this power of terminal described in signaling the to control power ratio of each resource element with the OFDM symbol not comprising channel measurement pilot frequency:

The transmitting power of each resource element of the data channel on the OFDM symbol at signaling channel measurement pilot frequency place is B, do not have the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency to be A, described notification module is by the power that comprises each resource element of OFDM symbol of channel measurement pilot frequency described in the ratio notification terminal of feedback B/A and the power ratio of each resource element of OFDM symbol not comprising channel measurement pilot frequency;

On described power control module setting OFDM symbol, resource element average power refers to, if channel measurement pilot frequency place OFDM symbol comprises the resource element of N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is reduced to n-i by power control module, and be evenly distributed to by described power n-i on the resource element of described N number of transmission data, and the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency is not had to remain unchanged;

After setting, described B/A=(n-i)/n, i is the decrease of the gross power of described N number of resource element.

6. system as claimed in claim 5, is characterized in that:

On described power control module setting OFDM symbol, resource element average power refers to, if channel measurement pilot frequency place symbol comprises the resource element of N number of transmission data, and the gross power of described N number of resource element is n, the gross power of described N number of resource element is enlarged into n ﹢ j by power control module, and be evenly distributed on the resource element of described N number of transmission data by described power n ﹢ j, and the transmitting power of each resource element of data channel on the OFDM symbol of channel measurement pilot frequency is not had to remain unchanged;

7. the system as described in claim 5 or 6, is characterized in that:

Power control module presets m kind power control mode, and be often kind of mode serial number, when adopt wherein a kind of mode time, notification module adopts this power of signaling terminal to control the numbering of corresponding mode, and terminal knows the value of described B/A under the mode that this power controls and which according to described numbering.

8. system as claimed in claim 7, is characterized in that:

The value of described m is 4, the mode that described notification module adopts 2 these power of bit signalling notification terminal to control.