CN102026351A

CN102026351A - Method and device for controlling power of downlink closed loop in long-term evolution system

Info

Publication number: CN102026351A
Application number: CN2010106196597A
Authority: CN
Inventors: 倪立华; 牛纲
Original assignee: Datang Mobile Communications Equipment Co Ltd
Current assignee: Datang Mobile Communications Equipment Co Ltd
Priority date: 2010-12-31
Filing date: 2010-12-31
Publication date: 2011-04-20

Abstract

The embodiment of the invention discloses a method and a device for controlling power of a downlink closed loop in a long-term evolution system and relates to the technical field of wireless communication for increasing the efficiency of controlling the power of a downlink channel. In the invention, a base station confirms a data transmission code rate of the downlink channel according to the downlink channel quality information fed back by a terminal, a power adjusting mode corresponding to the data transmission code rate is confirmed according to a preset relationship between a code ratio scope and the power adjusting mode, and a signal emitting power of the downlink channel is adjusted according to the power adjusting mode. In the invention, the base station is not required to send a power downlink power control parameter to the terminal UE and can adjust the signal emitting power of the downlink channel when the statistic data transmission code ratio of the downlink channel is in the preset code ratio scope, without waiting for the downlink control parameters at two sides of the base station and the UE being effective, therefore greatly increasing the efficiency of controlling the power of the downlink channel.

Description

Downlink closed-loop power control method and device in long-term evolution system

Technical Field

The present invention relates to the field of wireless communication technologies, and in particular, to a method and an apparatus for controlling downlink closed loop power in a long term evolution system.

Background

In a Long Term Evolution (LTE) system, a single cell needs to occupy a large amount of spectrum resources and is limited by the spectrum resources, co-frequency networking is imperative, the importance of reducing co-frequency interference is particularly prominent, and the inter-cell interference can be effectively reduced by using downlink closed-loop power control. Meanwhile, the throughput of the system can be effectively improved by reasonably adjusting the power of signals transmitted to each terminal in the cell.

When a base station in an LTE system transmits a signal through a Physical Downlink Shared Channel (PDSCH), the power used for transmitting service data on a Resource Element (RE) is determined in the following manner:

firstly, the base station determines the value of the semi-static power control parameter in the following table 1;

TABLE 1

Wherein, P _ A is configured through the high layer RRC signaling of the base station.

For each UE, the ratio of PDSCH to EPRE of a cell-specific Reference Signal (RS) remains equal among all REs within an OFDM symbol containing the RS, and is held at ρ_BDenotes ρ_B＝E_B/E_CRSIn which E_BTransmitting power of RE used for bearing service data in OFDM bearing pilot signals on PDSCH;

for each UE, the ratio of PDSCH to EPRE of a cell-specific RS remains equal among all REs within an OFDM symbol that does not contain a cell-specific RS, and is held at ρ_ADenotes ρ_A＝E_A/E_CR_SIn which E_AIs the transmission power of REs for carrying traffic data within OFDM not carrying pilot signals on PDSCH.

Then, when carrying out PDSCH transmission by using a transmission diversity precoding mode of 4 cell-specific antenna ports, the base station calculates rho according to the following formula_AThe value of (c):

ρ_A＝δ_power-offset+P_A+10log₁₀(2)[dB]；

in other transmission modes, the base station calculates ρ according to the following formula_AThe value of (c):

ρ_A＝δ_power-offset+P_A[dB]。

then, the base station searches the following table 2 according to the determined parameter P _ B value and the antenna port number P value to obtain rho_B/ρ_AA value of (d);

TABLE 2

Then, the base station bases on ρ_AAnd ρ_B/ρ_AIs calculated to obtain rho_BA value of (d);

finally, the base station bases on ρ_A、E_CRSAnd the formula rho_A＝E_A/E_CRSCalculating to obtain E_AObtaining the transmitting power of RE used for bearing service data in OFDM which does not bear pilot signals on PDSCH; according to rho_B、E_CRSAnd the formula rho_B＝E_B/E_CRSCalculating to obtain E_BThe value of (2) is obtained, namely the transmitting power of the RE used for bearing the service data in the OFDM bearing the pilot signal on the PDSCH.

Meanwhile, the base station needs to broadcast the P value to the UE and E value through a broadcast channel (PBCH)_CRSThe value and P _ B value are sent to the terminal through SIB, the P _ A value is sent to UE through RRC signaling, and the UE determines E according to the following mode same as the base station after obtaining the parameters_AAnd E_BThe value of (c):

firstly, when the UE uses the transmit diversity precoding mode of 4 cell-specific antenna ports to perform PDSCH transmission, rho is calculated according to the following formula_AThe value of (c):

ρ_A＝δ_power-offset+P_A+10log₁₀(2)[dB]；

in other transmission modes, ρ is calculated as follows_AThe value of (c):

ρ_A＝δ_power-offset+P_A[dB]。

then, the UE checks the table 2 to obtain rho according to the received parameter P _ B value and the number P value of the antenna ports_B/ρ_AA value of (d);

then, the UE depends on ρ_AAnd ρ_B/ρ_AIs calculated to obtain rho_BA value of (d);

finally, the UE depends on ρ_A、E_CRSAnd the formula rho_A＝E_A/E_CRSCalculating to obtain E_AObtaining the transmitting power of RE used for bearing service data in OFDM which does not bear pilot signals on PDSCH; according to rho_B、ECRSAnd the formula rho_B＝E_B/E_CRSCalculating to obtain E_BThe value of (2) is obtained, namely the transmitting power of the RE used for bearing the service data in the OFDM bearing the pilot signal on the PDSCH. UE according to obtained E_AAnd E_BThe value of (d) is used for demodulation of the PDSCH.

If the base station needs to adjust the transmission power of the PDSCH, the adjustment can be achieved by adjusting the value of P _ a, and the adjusted value of P _ a is sent to the UE through RRC signaling.

In the process of implementing the invention, the inventor finds that the following technical problems exist in the prior art:

firstly, a downlink power control parameter P _ A is transmitted through an RRC signaling, has large delay and cannot respond to channel fading in time;

secondly, a closed-loop power control mode is adopted, parameters on two sides of a base station and UE need to take effect simultaneously, and the requirement on signaling processing time delay is high;

third, the prior art can only adjust the transmission power of the PDSCH by adjusting the value of P _ a, and is limited by the protocol, and the adjustment range of the value of P _ a is limited, so that the optimal power control effect cannot be achieved.

Disclosure of Invention

The embodiment of the invention provides a downlink closed loop power control method and a downlink closed loop power control device in a long-term evolution system, which are used for improving the efficiency of performing power control on a downlink channel.

A downlink closed loop power control method in a long term evolution system comprises the following steps:

the base station determines the data transmission code rate of a downlink channel according to the downlink channel quality information fed back by the terminal;

the base station determines a power adjustment mode corresponding to the data transmission code rate according to the corresponding relation between a preset code rate value range and the power adjustment mode;

and the base station adjusts the signal transmitting power of the downlink channel according to the power adjusting mode.

A downlink closed loop power control device in a long term evolution system, the device comprising:

a code rate statistic unit, configured to determine a data transmission code rate of a downlink channel according to downlink channel quality information fed back by a terminal;

a power adjustment mode determining unit, configured to determine a power adjustment mode corresponding to the data transmission code rate according to a correspondence between a preset code rate value range and the power adjustment mode;

and the power adjusting unit is used for adjusting the signal transmitting power of the downlink channel according to the power adjusting mode.

In the invention, a base station determines the data transmission code rate of a downlink channel according to the downlink channel quality information fed back by a terminal; determining a power adjustment mode corresponding to the data transmission code rate according to the corresponding relation between a preset code rate value range and the power adjustment mode; and adjusting the signal transmitting power of the downlink channel according to the power adjusting mode. Therefore, in the invention, the base station does not need to transmit the power downlink power control parameters to the UE, the base station adjusts the signal transmitting power of the downlink channel when the data transmission code rate of the statistical downlink channel is in the preset code rate value range, and the power adjustment is not needed to be carried out after the downlink power control parameters on the two sides of the base station and the UE are effective, thereby greatly improving the efficiency of carrying out the power control on the downlink channel.

Drawings

FIG. 1 is a schematic flow chart of a method provided by an embodiment of the present invention;

FIG. 2A is a diagram illustrating an SNR-to-code rate mapping relationship curve according to an embodiment of the present invention;

fig. 2B is a schematic diagram illustrating PDSCH power control in an embodiment of the present invention;

fig. 3 is a schematic structural diagram of an apparatus according to an embodiment of the present invention.

Detailed Description

In order to improve the efficiency of performing power control on a downlink channel, an embodiment of the present invention provides a downlink closed-loop power control method in a long term evolution system.

Referring to fig. 1, a method for controlling downlink closed loop power in a long term evolution system according to an embodiment of the present invention specifically includes the following steps:

step 10: the base station determines the data transmission code rate of a downlink channel according to the downlink channel quality information fed back by the terminal;

step 11: the base station determines a power adjustment mode corresponding to the data transmission code rate according to the corresponding relation between a preset code rate value range and the power adjustment mode;

step 12: and the base station adjusts the signal transmitting power of the downlink channel according to the power adjusting mode.

The specific implementation of step 10 may be as follows:

and respectively determining the data transmission code rates of the downlink channels by the base station according to the downlink channel quality information continuously fed back by the terminal for N times to obtain N data transmission code rates, wherein N is an integer not less than 1. Correspondingly, in step 11, when the base station determines that the N data transmission code rates are all within the preset code rate value range, the base station determines the power adjustment mode corresponding to the code rate value range according to the corresponding relationship. The specific implementation can be as follows:

when the N data transmission code rates are all larger than a preset high code rate threshold value Th_downThen, determining the power adjustment mode according to the corresponding relation as follows: adjusting the signal transmitting power of the downlink channel down by a first step size value delta_down(ii) a Or,

when the N data transmission code rates are all smaller than a preset low code rate threshold value Th_upThen, determining the power adjustment mode according to the corresponding relation as follows: adjusting the signal transmitting power of the downlink channel by a second step value delta_up，low(ii) a Or,

all the N data transmission code rates are at a low code rate threshold value Th_upAnd a high bit rate threshold value Th_downAnd when the power is adjusted, determining a power adjustment mode according to the corresponding relation as follows: adjusting the signal transmitting power of the downlink channel by a third step value delta_up，high。

The signal transmitting power of the downlink channel is adjusted downwards by a first step size value delta_downThe specific implementation can adopt the following two modes:

first, according to formula lgx ═ 20 ═ Δ_downDetermining a multiple x of adjusting the amplitude of the dedicated pilot frequency and the dedicated data transmitted by the downlink channel: the amplitude of the special pilot frequency and special data transmitted by the downlink channel is adjusted down by x times;

the method can be applied to the case that the downlink channel adopts the transmission mode 7 or 8 in the long term evolution system.

Second, according to formula lgx ═ 20 ═ Δ_downEnsure thatAnd adjusting the multiple x of the amplitude of the special data transmitted by the downlink channel: and the amplitude of the special data transmitted by the downlink channel is adjusted down by x times.

The method can be applied to the condition that the downlink channel uses the common pilot frequency to carry out channel estimation and the modulation mode is Quadrature Phase Shift Keying (QPSK).

The signal transmitting power of the downlink channel is adjusted up by the second step value delta_up，lowThe specific implementation can adopt the following two modes:

first, according to formula lgx ═ 20 ═ Δ_up，lowDetermining and adjusting the multiple x of the amplitude of the special pilot frequency and the special data transmitted by the downlink channel, and adjusting the amplitude of the special pilot frequency and the special data transmitted by the downlink channel by x times;

Second, according to formula lgx ═ 20 ═ Δ_up，lowAnd determining and adjusting the multiple x of the amplitude of the special data transmitted by the downlink channel, and adjusting the amplitude of the special data transmitted by the downlink channel by x.

The signal transmitting power of the downlink channel is adjusted up to a third step length value delta_up，highThe specific implementation can adopt the following two modes:

first, according to formula lgx ═ 20 ═ Δ_up，highDetermining a multiple x for adjusting the amplitude of the dedicated pilot frequency and the dedicated data transmitted by the downlink channel; the amplitude of the special pilot frequency and special data transmitted by the downlink channel is adjusted up by x times;

Second, according to formula lgx ═ 20 ═ Δ_up，highDetermining a multiple x for adjusting the amplitude of the dedicated data transmitted by the downlink channel; and the amplitude of the special data transmitted by the downlink channel is adjusted up by x times;

In the method, the Th_downMay be a value of not less than 0.8 and not more than 1, preferably, Th_downIs 1. Of course, Th_downBut can also be any other of greater than 0, not greater than 1, and greater than Th_upThe numerical value of (c).

The Th_upMay be a value of not less than 0.02 and not more than 0.1, preferably, Th_upIs 0.05. Of course, Th_upBut can be any other of more than 0, not more than 1, and less than Th_downThe numerical value of (c).

Preferably, said Δ_downCan be 1dB, of course, Δ_downAny other value not less than 0 is also possible.

Preferably, said Δ_up，lowIs taken to be 1dB, of course, Delta_up，lowBut also can be any other value not less than 0 and greater than delta_up，highThe numerical value of (c).

Preferably, said Δ_up，highIs 0.5dB, of course, Delta_up，highBut also can be any other value not less than 0 and less than delta_up，lowThe numerical value of (c).

Preferably, the value of N is 4. Of course, N may be any other integer not less than 1.

In the present invention, the downlink channel is a Physical Downlink Shared Channel (PDSCH) or a Physical Downlink Control Channel (PDCCH), and may be a downlink channel in any other LTE system.

The implementation manner of step 10 may also adopt other manners besides determining the data transmission code rate of the downlink channel according to the downlink channel quality information fed back by the terminal for N consecutive times, for example, determining the data transmission code rate of the downlink channel according to the downlink channel quality information fed back by the terminal for the last time at a preset sampling time point, and the like. Any way of determining the data transmission code rate of the downlink channel according to the downlink channel quality information fed back by the terminal is within the protection scope of the invention.

The corresponding relationship between the code rate value range and the power adjustment mode in step 11 is not limited to the above listed modes, for example, the signal transmission power of the downlink channel may be adjusted downward by a value when the statistical data transmission code rate is greater than a threshold, and the signal transmission power of the downlink channel may be adjusted upward by a value when the statistical data transmission code rate is less than the threshold, and so on. The corresponding relation between the code rate value range in any form and the power adjustment mode, and other modes are all in the protection range of the invention.

The present invention is described in detail below:

in the transmission mode 7 in the LTE system, a PORT (PORT)5 beamforming transmission mode is used, and in this transmission mode, the UE uses the dedicated pilot as a reference signal for channel estimation, so as long as the magnitudes of the PDSCH and the UE dedicated pilot are consistent, the UE can use dynamic power configuration parameters to adjust power without following the RRC-configured P _ a and P _ B parameters, so as to achieve the effect of taking throughput and interference into account.

The scheme for PDSCH dynamic power control using PORT5 is as follows:

before the scheme is implemented, the following parameters in the following table 3 need to be preset:

TABLE 3

The scheme comprises the following steps:

step 1: the base station respectively counts the code rate of data transmission of the PDSCH according to CQI or other downlink channel quality feedback information fed back by the UE for N times continuously to obtain N data transmission code rates, and preferably selects a sliding window counting method, but is not limited to the method;

step 2: if the N data transmission code rates are all larger than or equal to the predefined threshold value Th_downThe corresponding average symbol SNR is the SNR in FIG. 2A_downThen, it means that the UE is located in the area 3 in fig. 2B, the throughput improvement efficiency (i.e. the throughput improvement amount that can be brought by increasing the unit power) is not high, and the power is adjusted downward by one step Δ_down(dB)；

And step 3: if N data transmission code rates are all lower than a predefined threshold value Th_upThe corresponding average symbol SNR is the SNR in FIG. 2A_upThen it means that the UE is located in region 1 in fig. 2B, throughput improvement is not efficient, but considering that the UE may need to guarantee a minimum data rate, power is adjusted up by one step Δ_up，low(dB), the configuration of the step length needs to consider both the throughput improvement efficiency and the service configuration condition in the current subframe; if the number of the UE configured in the subframe is large and the proportion of the resource occupied by the UE is small, the setting step length is large; if the number of the UE configured in the subframe is small and the proportion of the resource occupied by the UE is large, the setting step length is small;

and 4, step 4: if N data transmission code rates are all between the predefined threshold (Th)_up，Th_down) In between, it means that the UE is located in the area 2 in fig. 2B, and the throughput improvement efficiency is relatively high; the power is taken into account for the up-regulation by one step delta_up，high(dB)。

In the above steps 2 to 4, the power of the PDSCH can be adjusted by increasing or decreasing the amplitude of the dedicated pilot and the dedicated data relative to the cell common pilot.

And (3) analyzing a scheme:

dividing the cell into three parts according to the distance between the UE and the base station, as shown in FIG. 2B; the scheme is based on the idea of properly reducing the transmitting power of the UE in the central area (namely area 3) of the cell, improving the power of peripheral UE and further improving the data rate of the peripheral UE, and the transmission power of the UE in the area 2 is improved more importantly from the aspect of improving the throughput and efficiency; limited power resources are used to a place where the throughput of the system can be improved, and for an area 1 where the throughput improvement efficiency is not high but the minimum data rate of the UE may need to be ensured, the power can be improved or reduced appropriately according to the situation; therefore, the resource efficiency of the system can be improved, and the interference among cells can be reduced;

the scheme parameters are considered as follows:

code rate threshold Th_downAnd Th_upThe first inflection point (SNR) can be determined according to the SNR-code rate mapping relation curve shown in fig. 2A obtained by simulation, specifically, the inflection point of the curve is determined, and the first inflection point (SNR is obtained)_up) The corresponding code rate is determined as Th_upThe first inflection point (i.e., SNR)_down) The corresponding code rate is determined as Th_down。

If it is desired that certain UEs within a cell can reach peak rate, the power down step size Δ for these UEs_downCan be set to 0, otherwise the power down step Δ is adjusted_downIs not 0;

this method is also suitable for single stream transmission of PORT7 or PORT8 in transmission mode 8.

When the common pilot frequency is used for channel estimation and the modulation mode is QPSK, the QPSK demodulation is only related to the quadrant where the constellation point is located and is not related to the relative position in the quadrant, so the power control method introduced by the invention is also suitable for PDSCH transmission which uses the common pilot frequency for channel estimation and has the QPSK modulation mode, and the power adjustment method adjusts the PDSCH power in a mode of increasing or decreasing the amplitude of the special data relative to the common pilot frequency of the cell.

Referring to fig. 3, an embodiment of the present invention further provides a downlink closed-loop power control apparatus in a long term evolution system, where the apparatus includes:

a code rate statistics unit 30, configured to determine a data transmission code rate of a downlink channel according to downlink channel quality information fed back by a terminal;

a power adjustment mode determining unit 31, configured to determine a power adjustment mode corresponding to the data transmission code rate according to a correspondence between a preset code rate value range and the power adjustment mode;

a power adjusting unit 32, configured to adjust the signal transmitting power of the downlink channel according to the power adjusting manner.

The code rate statistic unit 30 is configured to:

respectively determining data transmission code rates of a downlink channel according to downlink channel quality information fed back by a terminal for N times continuously to obtain N data transmission code rates, wherein N is an integer not less than 1;

the power adjustment mode determining unit 31 is configured to:

and when the N data transmission code rates are determined to be in a preset code rate value range, determining a power adjustment mode corresponding to the code rate value range according to the corresponding relation.

The power adjustment mode determining unit 31 is configured to:

The power adjustment unit 32 is configured to:

when the downlink channel adopts transmission mode 7 or 8 in the long term evolution system, Δ is obtained according to formula lgx ═ 20_downDetermining a multiple x of adjusting the amplitude of the dedicated pilot frequency and the dedicated data transmitted by the downlink channel: the amplitude of the special pilot frequency and special data transmitted by the downlink channel is adjusted down by x times; or,

when the downlink channel uses the common pilot for channel estimation and the modulation method is QPSK, Δ is obtained according to the formula lgx × 20 ═ Δ_downDetermining a multiple x for adjusting the amplitude of the dedicated data transmitted by the downlink channel: and the amplitude of the special data transmitted by the downlink channel is adjusted down by x times.

The power adjustment unit 32 is configured to:

when the downlink channel adopts transmission mode 7 or 8 in the long term evolution system, Δ is obtained according to formula lgx ═ 20_up，lowDetermining and adjusting the multiple x of the amplitude of the special pilot frequency and the special data transmitted by the downlink channel, and adjusting the amplitude of the special pilot frequency and the special data transmitted by the downlink channel by x times; or,

when the downlink channel uses the common pilot for channel estimation and the modulation scheme is QPSK, Δ is obtained according to the formula lgx ═ 20_up，lowAnd determining and adjusting the multiple x of the amplitude of the special data transmitted by the downlink channel, and adjusting the amplitude of the special data transmitted by the downlink channel by x.

The power adjustment unit 32 is configured to:

when the downlink channel adopts transmission mode 7 or 8 in the long term evolution system, Δ is obtained according to formula lgx ═ 20_up，highDetermining a multiple x for adjusting the amplitude of the dedicated pilot frequency and the dedicated data transmitted by the downlink channel; the amplitude of the special pilot frequency and special data transmitted by the downlink channel is adjusted up by x times; or,

when the downlink channel uses the common pilot for channel estimation and the modulation scheme is QPSK, Δ is obtained according to the formula lgx ═ 20_up，highDetermining a multiple x for adjusting the amplitude of the dedicated data transmitted by the downlink channel; and the amplitude of the special data transmitted by the downlink channel is adjusted up by x times.

The Th_downNot less than 0.8, and not more than 1. The Th_upNot less than 0.02, and not more than 0.1. Said Δ_downIs 1 dB. Said Δ_up，lowIs 1 dB. Said Δ_up，highIs 0.5 dB. And N is 4. The downlink channel is a PDSCH or a PDCCH.

The downlink closed-loop power control device in the long term evolution system provided by the embodiment of the invention can be network side equipment such as a base station and the like which can communicate with the UE.

In conclusion, the beneficial effects of the invention include:

in the scheme provided by the embodiment of the invention, a base station determines the data transmission code rate of a downlink channel according to the downlink channel quality information fed back by a terminal; determining a power adjustment mode corresponding to the data transmission code rate according to the corresponding relation between a preset code rate value range and the power adjustment mode; and adjusting the signal transmitting power of the downlink channel according to the power adjusting mode.

Therefore, in the invention, the base station does not need to transmit the power downlink power control parameters to the UE, the base station adjusts the signal transmitting power of the downlink channel when the data transmission code rate of the statistical downlink channel is in the preset code rate value range, and the power adjustment is not needed to be carried out after the downlink power control parameters on the two sides of the base station and the UE are effective, thereby greatly improving the efficiency of carrying out the power control on the downlink channel. Meanwhile, the base station can adjust the power of the downlink channel according to a preset power adjustment mode, the adjustment range is not limited by a protocol, and the effect of power control can be improved.

Compared with the existing mode of transmitting power control parameters through RRC signaling, the power control method has the advantages of smaller time delay and stronger adaptability to channel fading.

The rapid downlink closed-loop power control method can fully utilize the cell power, improve the system resource efficiency, control the maximum power of the UE at the edge of the cell and reduce the interference among cells with the same frequency.

The present invention is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. A downlink closed loop power control method in a long term evolution system is characterized in that the method comprises the following steps:

2. The method of claim 1, wherein the determining, by the base station, the data transmission code rate of the downlink channel according to the downlink channel quality information fed back by the terminal comprises:

the base station respectively determines data transmission code rates of a downlink channel according to the downlink channel quality information fed back by the terminal for N times continuously to obtain N data transmission code rates, wherein N is an integer not less than 1;

the base station determines the power adjustment mode corresponding to the data transmission code rate according to the corresponding relation between the preset code rate value range and the power adjustment mode, and the method comprises the following steps:

3. The method of claim 2, wherein when it is determined that the N data transmission code rates are all within a preset code rate value range, determining, according to the correspondence, a power adjustment manner corresponding to the code rate value range includes:

4. The method of claim 3, wherein the signal transmission power of the downlink channel is adjusted downward by a first step size Δ_downThe method comprises the following steps:

5. The method of claim 3, wherein the signal transmission power of the downlink channel is adjusted up by a second step value Δ_up，lowThe method comprises the following steps:

6. The method of claim 3, wherein the signal transmission power of the downlink channel is adjusted up by a third step value Δ_up，highThe method comprises the following steps:

7. The method of any of claims 3-6, wherein Th is_downNot less than 0.8 and not more than 1; or,

the Th_upNot less than 0.02 and not more than 0.1; or,

said Δ_downThe value of (a) is 1 dB; or,

said Δ_up，lowThe value of (a) is 1 dB; or,

said Δ_up，highThe value of (a) is 0.5 dB; or,

the N is 4; or,

the downlink channel is a Physical Downlink Shared Channel (PDSCH) or a Physical Downlink Control Channel (PDCCH).

8. A downlink closed loop power control device in a long term evolution system, the device comprising:

9. The apparatus of claim 8, wherein the code rate statistics unit is to:

the power adjustment mode determining unit is configured to:

10. The apparatus of claim 9, wherein the power adjustment manner determining unit is configured to:

11. The apparatus of claim 10, wherein the power adjustment unit is to:

employing a long-term evolution on said downlink channelWhen the transmission mode 7 or 8 enters the system, the value is Δ according to the formula lgx × 20_downDetermining a multiple x of adjusting the amplitude of the dedicated pilot frequency and the dedicated data transmitted by the downlink channel: the amplitude of the special pilot frequency and special data transmitted by the downlink channel is adjusted down by x times; or,

12. The apparatus of claim 10, wherein the power adjustment unit is to:

13. The apparatus of claim 10, wherein the power adjustment unit is to: the signal transmitting power of the downlink channel is adjusted up by a third step value delta in the following way_up，high：

When the downlink channel adopts transmission mode 7 or 8 in the long term evolution system, Δ is obtained according to formula lgx ═ 20_up，highDetermining a multiple x for adjusting the amplitude of the dedicated pilot frequency and the dedicated data transmitted by the downlink channel; and the amplitude of the special pilot frequency and special data transmitted by the downlink channel is adjusted up by x times(ii) a Or,