KR20150082147A - Method and apparatus for settting transmission power of downlink channel - Google Patents

Abstract

Disclosed are a method and an apparatus for setting a transmission power in a downlink channel of a communications system. A method for setting a transmission power of a downlink by a wireless terminal in an OFDM system comprises the processes of: obtaining a signaling parameter from a base station; and determining a first ratio of traffic data to a pilot (T2P) for first OFDM symbols, and a second ratio of traffic data to a pilot (T2P) for second OFDM symbols, wherein a ratio between the first ratio and the second ratio is determined to be 1, 4/5, 3/5, and 2/5, when the signaling parameter is 0, 1, 2, and 3 for one cell specific antenna port respectively, and is determined to be 5/6, 1, 3/4, and 1/2, when the signaling parameter is 0, 1, 2, and 3 for two or four cell specific antenna port respectively.

Description

[0001] METHOD AND APPARATUS FOR SETTING TRANSMISSION POWER OF DOWNLINK CHANNEL [0002]

The present invention relates to a method and apparatus for setting transmission power of a downlink channel of a communication system.

A Radio Access Network (RAN) 1 # 51 conference enables efficient power and bandwidth utilization at the e-Node B (i.e., base station) for all orthogonal frequency division multiplexing (OFDM) symbols, In order to minimize the signaling or prediction effort for the data-to-reference signal (RS) ratio, we have agreed the following:

For each user equipment (UE), the Physical Downlink Shared Channel (PDSCH) -to-RS EPRE ratios between the resource elements (REs) in all OFDM symbols including the RS are the same, .

For each UE, the PDSCH-to-RS EPRE ratios between REs in all OFDM symbols that do not include RS are the same and are denoted as P_B.

For each UE, P_A and P_B are potentially different due to different PDSCH EPREs.

The ratio of P_A to P_B is known in the UE. This ratio can be obtained from the signaled RS boosting value or from other signaling needed to obtain this ratio.

Note that the power available from each antenna port for subcarriers other than reference signals, such as data subcarriers, varies from one OFDM symbol to another. Maintaining the same power level across the antennas in these subcarriers results in inefficient use of power, since the power level is limited to the minimum power level available from a given antenna port, although other ports may have available extra power do. Likewise, keeping the power level the same across OFDM symbols in these subcarriers is also a problem because the power level is limited to the minimum power level available in one OFDM symbol, although other OFDM symbols may have extra power available Resulting in inefficient use of power. In order to keep the power level the same across the symbols, it may be another solution to puncture some data subcarriers in OFDM symbols including pilot signals. However, this scheme causes a waste of subcarrier resources and degrades system performance and capacity.

It is therefore an object of the present invention to provide an improved method and circuit for efficiently utilizing power during wireless data communication between a plurality of transmit antennas.

It is still another object of the present invention to provide a method and a circuit for transmitting power setting information in a physical downlink shared channel (PDSCH).

According to an aspect of the present invention, there is provided a method of setting downlink transmission power by a wireless terminal in an Orthogonal Frequency Division Multiplexing (OFDM) system, the method comprising: acquiring a signaling parameter from a base station; (T2P) for the first OFDM symbols and a second ratio of the traffic data to the pilot (T2P) for the second OFDM symbols, based on the number of cell specific antenna ports Wherein the ratio of the first ratio to the second ratio is such that for one cell specific antenna port the ratio of the signaling parameters is 0, 1, 2, 3 1, 2, and 3, respectively, for two or four cell-specific antenna ports, respectively, and are determined to be 1, 4/5, 3/5, 1, 3/4, 1/2.

According to another aspect of the present invention, there is provided an apparatus in a wireless terminal for setting downlink transmission power in an OFDM system, the apparatus comprising: an antenna unit for receiving signaling parameters from a base station; Based on the number, a ratio between a first ratio of traffic data to pilot for the first OFDM symbols and a second ratio of traffic data to pilot for the second OFDM symbols is determined Wherein the ratio of the first ratio to the second ratio is set to 1, 4/5, 3 < RTI ID = 0.0 > / 5, 2/5, and when the signaling parameters are 0, 1, 2, and 3 for 2 or 4 cell specific antenna ports, it is 5/6, 1, 3/4, 1/2 .

According to another aspect of the present invention, there is provided a method for setting downlink transmission power by a base station in an OFDM system, the method comprising: transmitting signaling parameters to wireless terminals in a cell; And transmitting traffic data using a first ratio of the pilot and a second ratio of the traffic data to the pilot for the second OFDM symbols, 2 ratio is determined based on the signaling parameter and the number of cell-specific antenna ports provided in the base station, and the ratio of the first ratio to the second ratio is determined based on the cell- 4/5, 3/5 and 2/5 when the signaling parameters are 0, 1, 2 and 3, respectively, and for the 2 or 4 cell specific antenna ports, the signaling parameters are 0, 1, 2, 3 people Respectively, are determined as 5/6, 1, 3/4, and 1/2, respectively.

According to another aspect of the present invention, there is provided an apparatus in a base station for setting downlink transmission power in an OFDM system, the apparatus comprising: an antenna unit for transmitting signaling parameters to wireless terminals in a cell; And a transmitter for transmitting traffic data using either a first ratio of the pilot and a second ratio of the traffic data to the pilot for the second OFDM symbols, 2 ratio is determined based on the signaling parameter and the number of cell-specific antenna ports provided in the base station, and the ratio of the first ratio to the second ratio is determined based on the cell- 4/5, 3/5 and 2/5 when the signaling parameters are 0, 1, 2 and 3, respectively, and for the 2 or 4 cell specific antenna ports, the signaling parameters are 0,1, 2, and 3, respectively, are determined as 5/6, 1, 3/4, and 1/2.

Figure 1 schematically illustrates an Orthogonal Frequency Division Multiplexing (OFDM) transceiver chain suitable for implementing the principles of the present invention.
2 is a cross- MIMO < / RTI > suitable for implementing the principles of the present invention (Multiple Input Multiple Output) transceiver chain.
Figure 3 schematically illustrates an example of a reference signal transmission over six subcarriers in one subframe through four transmit antennas 4Tx suitable for implementing the principles of the present invention.
Figure 4 schematically shows an example of a reference signal transmission over six subcarriers in one subframe through two transmit antennas 2Tx suitable for implementing the principles of the present invention.
Figure 5 schematically shows an example of a reference signal transmission over six subcarriers in one subframe through one transmit antenna (1Tx) suitable for implementing the principles of the invention.
FIG. 6 schematically shows an example of mapping of downlink reference signals in OFDM symbols 1 and 2 for four transmit antennas.
FIG. 7 schematically illustrates a wireless system including a base station (eNodeB) and a user terminal in accordance with an embodiment of the present invention.
FIG. 8 is a flowchart illustrating a process of transmitting downlink power setting information in a base station (BS) according to an embodiment of the present invention.
9 schematically shows a flow chart illustrating a process of calculating power setting information in a unit of a user terminal as an embodiment constructed in accordance with the principles of the present invention.

Methods and apparatus for improving performance in a communication system and reducing the overhead of channel quality indication feedback are proposed.

BRIEF DESCRIPTION OF THE DRAWINGS Aspects, features, and advantages of the present invention will become apparent from the following detailed description, by way of illustration of many specific embodiments and implementations, including the best mode contemplated for carrying out the invention. The present invention is also capable of other and various embodiments and several details thereof may be modified in various obvious aspects without departing from the spirit and scope of the invention. Accordingly, the drawings and description are to be regarded as illustrative in nature and not as restrictive. The invention is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings.

Figure 1 shows an Orthogonal Frequency Division Multiplexing (OFDM) transceiver chain. Control signals or data 111 are modulated by a modulator 112 and converted from serial to parallel by a serial to parallel (S / P) converter 113, in a transmitter chain 110 of a communication system using OFDM technology. do. An inverse fast Fourier transform (IFFT) unit 114 is used to transmit the signal in the frequency domain to the time domain. A cyclic prefix (CP) or a zero prefix (ZP) is added to each OFDM symbol by the CP inserter 116 to avoid or mitigate the influence due to multipath fading. Thus, the signal is transmitted by a transmitter (Tx) front end processor 117 and at least one antenna (not shown), or a fixed wire or cable. The signal is transmitted through the air from one or more antennas driven by the transmitter front end processor 117, to undergo multipath fading and arrive at the receiver. It should be noted that the multipath fading channel shown in FIG. 1 represents a transmission medium (e.g., the atmosphere), and the multipath fading channel is not a component connected to a receiver or a transmitter. In the receiver chain 120, the signal received by the receiver (Rx) pre-processing section 121 is processed by the CP de-selecting section 122 on the assumption that perfect time and frequency synchronization have been achieved. A Fast Fourier Transform (FFT) unit 124 transmits the received signal from the time domain to the frequency domain for subsequent processing.

The total bandwidth of the OFDM system is divided into narrowband frequency units called subcarriers. The number of subcarriers is equal to the FFT / IFFT size N used in the system. In general, since some subcarriers at the edge of the frequency spectrum are reserved as guard subcarriers, the number of subcarriers used for data is less than N. [ In general, no information is transmitted on the protected subcarriers.

The basic structure of a multi-carrier signal in the time domain generally consists of time frames, time slots and OFDM symbols. One frame is composed of a large number of time slots, whereas each time slot is composed of a large number of OFDM symbols. The OFDM time domain waveform is generated by applying an IFFT to the frequency domain OFDM signals. To form an OFDM symbol, a copy of the last part of the time waveform known as the CP is inserted at the beginning of the waveform. Through the cyclic prefix extension, the samples required to perform the FFT at the receiver can be obtained anywhere over the entire length of the symbol. This provides multipath immunity as well as resistance to symbol time synchronization errors.

Multiple input multiple output (MIMO) schemes use multiple transmit antennas and multiple receive antennas to improve the capacity and reliability of a wireless communication channel. The MIMO system guarantees a linear increase in capacity with K, where K denotes the minimum number of transmit antennas M and receive antennas N, i.e. K = min (M, N). A simple example of a 4 X 4 MIMO system is shown in FIG. In this example, four different data streams are transmitted separately from the four transmit antennas. The transmitted signals are received at four receive antennas. Any type of spatial signal processing to recover the four data streams is performed on the received signals. One example of spatial signal processing is Vertical Bell Laboratories Layered Space-Time (V-BLAST), which uses continuous interference cancellation to recover transmitted data streams. Other variations of MIMO schemes include schemes that perform spatial-temporal coding across transmit antennas (e.g., D-BLAST (Diagonal Bell Laboratories Layered Space-Time)) and beams such as SDMA There are foaming schemes.

A downlink reference signal mapping for four transmit antennas in the 3GPP LT3GPP LTE (3 ^rd Generation Partnership Project Long Term Evolution) system is shown in FIG. And R _P denotes a resource element used for transmission of the reference signal at the antenna port p. It can be noted that the density at antenna ports 2 and 3 is one-half the density at antenna ports 0 and 1. This causes the channel estimates for antenna ports 2 and 3 to be weaker than the channel estimates for antenna ports 0 and 1.

Similarly, FIG. 4 schematically shows a downlink reference signal mapping for two transmit antennas in a 3GPP LTE system, and FIG. 5 schematically shows a downlink reference signal mapping for one transmit antenna in a 3GPP LTE system. Respectively.

An example of a reference signal transmission from each of the four antenna ports over six subcarriers in the first three OFDM symbols is shown in FIG. The power available from each antenna port for subcarriers other than the reference signals, for example data subcarriers, varies from one OFDM symbol to another. Maintaining the same power level across the antennas in these subcarriers results in inefficient use of power, since the power level is limited to the minimum power level available from a given antenna port, although other ports may have available extra power do. Likewise, keeping the power level the same across OFDM symbols in these subcarriers is also a problem because the power level is limited to the minimum power level available in one OFDM symbol, although other OFDM symbols may have extra power available Resulting in inefficient use of power. In order to keep the power level the same across the symbols, it may be another solution to puncture some data subcarriers in OFDM symbols including pilot signals. However, this scheme causes a waste of subcarrier resources and degrades system performance and capacity.

Methods for calculating the traffic-to-pilot ratio (T2P ) in all OFDM symbols for 1, 2, and 4 e-NodeB transmit antenna cases (1, 2, 4Tx) .

In a first embodiment in accordance with the principles of the present invention, a method for calculating the P_A / P_B ratio from an RS boosting value represented by an RS overhead as a percentage of the total power in an RS OFDM symbol is presented. In addition, we use the P_A / P_B ratio obtained from the proposed method to estimate the T2Ps of all OFDM symbols over different transmit antennas for 1, 2 or 4 transmit antennas (1, 2 or 4Tx) can do.

The total available data power in a non-RS OFDM symbol is E _B and the total available data power in an RS OFDM symbol is E _A = (1-η _RS ) E _B where η _RS is the RS OFDM symbol ≪ / RTI > for the k-th user (i.e., UE), (P _{B, K} N _{B, K)} as, and the number of pairs of the sub-carrier allocation in the EPRE power and non -RS OFDM symbols (P _{A, K} N _{A, K} ) Pair is called the number of subcarriers allocated in the EPRE power and RS OFDM symbols.

이며, 여기서 매 6개의 부반송파들 중 2개는 RS OFDM 심볼들에서 RS를 위해 예비된다(도 1 및 2 참조). 또한, 2개의 데이터 EPRE들 간의 비는 하기 <수학식 1>과 같이 제안된다.(1) For two Tx (2 eNode-B transmit antennas) and 4 Tx cases, due to the RS structure in LTE,

Where two of every six subcarriers are reserved for RS in RS OFDM symbols (see FIGS. 1 and 2). Also, the ratio between the two data EPREs is proposed as Equation (1) below.

인, 즉 최대 전력이 비-RS OFDM 심볼들에서 이용되는 비-RS OFDM 심볼들에 대한 전력 제어 정책을 가정하면, 하기 <수학식 2>를 증명하기가 쉽다. Where k = 1, ...., K and K is the total number of scheduled UEs. Note that the above ratio allows maximum power to be used simultaneously in both RS and non-RS OFDM symbols. To understand this,

Assuming a power control policy for non-RS OFDM symbols, i.e., where the maximum power is used in non-RS OFDM symbols, it is easy to prove Equation (2) below.

Equation (2) represents full utilization of power in RS OFDM symbols.

이며, 여기서 매 6개의 부반송파들 중 1개는 RS OFDM 심볼들에서 RS를 위해 예비된다(도 3 참조). 또한, 2개의 데이터 EPRE들 간의 비는 하기 <수학식 3>과 같이 제안된다.(2) One Tx case. Due to RS structure in LTE

Where one of every six subcarriers is reserved for RS in RS OFDM symbols (see FIG. 3). Further, the ratio between the two data EPREs is proposed as Equation (3).

Now, the above proposal is summarized into tables representing T2Ps in different antennas and different OFDM symbols. 'i' is an OFDM symbol index, i = 1, ..., 14, and t is a transmit antenna index.

는 일반 CP 상황에서 RS를 포함하는 OFDM 심볼들의 집합인 반면,

는 1Tx인 일반 CP 상황에서 RS를 포함하지 않는 OFDM 심볼들의 집합이다.Table 1 below shows all OFDM symbols in one subframe and T2Ps in all antennas for the case of 1Tx. here,

Is a set of OFDM symbols including RS in a normal CP situation,

Is a set of OFDM symbols that do not include RS in a normal CP situation of 1Tx.

는 일반 CP 상황에서 RS를 포함하는 OFDM 심볼들의 집합인 반면,

는 2Tx인 일반 CP 상황에서 RS를 포함하지 않는 OFDM 심볼들의 집합이다.Table 2 below shows all OFDM symbols in one subframe and T2Ps in all antennas for the 2Tx case. here,

Is a set of OFDM symbols including RS in a normal CP situation,

Is a set of OFDM symbols that do not include RS in a normal CP situation of 2Tx.

는 일반 CP 상황에서 RS를 포함하는 OFDM 심볼들의 집합인 반면,

는 4Tx인 일반 CP 상황에서 RS를 포함하지 않는 OFDM 심볼들의 집합이다.Table 3 below shows all OFDM symbols in one subframe and T2Ps in all antennas for the 4Tx case. here,

Is a set of OFDM symbols including RS in a normal CP situation,

Is a set of OFDM symbols that do not include RS in a normal CP situation of 4Tx.

를 알 필요가 있다. 실제로, T2P는 실제 전력보다 더 자주 이용되므로, k번째 UE는 P_A,K/ P_B,K를 얻기 위해 P_B,K/P_RS와 오버헤드 비

를 알 필요가 있다. 여기서,P_RS는 부반송파 당 RS 전력이다.k-th UE is P _{B, K} and the RS overhead to obtain P _{A, K}

. In fact, since T2P is used more often than real power, the k-th UE needs P _{B, K} / P _RS and overhead ratio to obtain P _{A, K} / P _B,

. Where P _RS is the RS power per subcarrier.

It is important to note that this ratio allows full utilization of power in both RS and non-RS OFDM symbols, but does not always require full power to be used. In fact, simply subtracting one of the K UEs is an example in which the eNB power is not fully utilized.

Example in -2 Tx

=1/3이면,

이다. 이는, RS 오버헤드를 위해 이용되는 총 전력과 총 대역폭의 퍼센트가 동일한 경우이다. 이 경우를, 종종 "비 부스팅된(non-boosted) RS"라고 한다.

= 1/3,

to be. This is the case when the total power used for RS overhead is equal to the percentage of total bandwidth. This case is often referred to as a "non-boosted RS &quot;.

2 . Alternatives to calculate T2Ps in 2,4 Tx cases

In the case of 4Tx, it is noteworthy that, in the case of RS OFDM symbols, it is not possible to transmit all the antennas at full power if T2P is set according to Table 3. [ This is due to the fact that, for a given OFDM symbol, only 1/2 of the antennas will transmit the RS and no other RSs are transmitted. If the T2P needs to be the same across all antennas in the RS OFDM symbol, it is proposed as a solution of Table 4 below.

In a second embodiment in accordance with the principles of the present invention, we have obtained Table 4 below as one possible 4Tx solution by varying the T2P values across both antennas and OFDM symbols.

In a third embodiment according to the principles of the present invention, 4Tx antennas share RS power overhead in RS OFDM symbols. This can be accomplished by schemes such as using virtual antennas to share power between different physical antennas. In this case, the virtual antenna is basically a fixed precoding vector applied to existing physical antennas, so that it is possible to potentially utilize the power on all the physical antennas. As a result, the T2P over the antennas and the OFDM symbols are shown in Table 5.

3. Signaling of parameters associated with DL PDSCH power setting

레벨을 나타내기 위해 몇 개의 비트들(예를 들어, 3 비트)을 이용할 수 있다는 것을 알았다. 또한, 상기에 나타난 표들(<표 1> 내지 <표 5>) 중 하나에 따라,

레벨과 모든 안테나들에 걸친 모든 T2P들을 계산하는 방법 모두를 나타내는 eNodeB 시그널링을 R_ovhd로 나타내었다.Also, the e-NodeB

It has been found that several bits (e.g., 3 bits) can be used to indicate the level. Further, according to one of the tables (Table 1 to Table 5) shown above,

The eNodeB signaling, which represents both the level and the method of calculating all T2Ps across all antennas, is denoted R_ovhd.

레벨 및 T2P들의 계산 방법에 맵핑하는 일 방법이 하기 <표 6>에 도시되어 있다. 3비트 R_ovhd의 일예가 이 예에 나타나 있으며, 4Tx 경우가 가정된다. 이 예에서, 상기 <표 3>에 명시된 방법들이 모든 R_ovhd 엔트리들에 대해 이용된다는 것을 알았다. R_ovhd에 이용되는 비트들의 수는 이 예에서 이용된 3 비트 이외의 개수가 될 수 있다.In the fourth embodiment according to the principle of the present invention, R_ovhd

Level and methods of calculating the T2Ps are shown in Table 6 below. An example of 3 bits R_ovhd is shown in this example, assuming 4Tx case. In this example, it has been found that the methods specified in Table 3 above are used for all R_ovhd entries. The number of bits used for R_ovhd may be a number other than three bits used in this example.

Table 2 < tb > < TABLE > Id = Table 4 Columns = 2 < tb > < TABLE & &Lt; tb &gt; &lt; TABLE &gt;

For example, a 3-bit R-ovhd design for the case of a 2Tx eNodeB transmit antenna is shown in Table 7 below, where all R_ovhd entries will use the T2P calculation method specified in Table 2 above.

레벨 및 T2P들의 계산 방법에 맵핑하는 다른 방법이 하기 <표 8>에 도시되어 있다. 3비트 R_ovhd의 일예가 이 예에 나타나 있으며, 4Tx 경우가 일 예로 가정된다. 이 예에서, 서로 다른 엔트리들에 대해 서로 다른 방법들이 이용될 수 있다는 것을 알았다. 즉, 첫 번째 5개의 엔트리들은 <표 3>에 명시된 T2P 계산 방법을 이용하는 반면, 마지막 3개의 엔트리들은 <표 5>에 명시된 T2P 계산 방법을 이용한다.In the fifth embodiment according to the principle of the present invention, R_ovhd

Level and methods of calculating T2Ps are shown in Table 8 below. An example of 3 bits R_ovhd is shown in this example, and a case of 4Tx is assumed as an example. In this example, we have seen that different methods can be used for different entries. That is, the first five entries use the T2P calculation method specified in Table 3, while the last three entries use the T2P calculation method specified in Table 5.

의 UE 특정 시그널링에 부가될 수 있으며(그러한

신호가 eNB로부터 전송되는 경우), 여기서 UE 특정 시그널링은 RRC 시그널링을 통해 반정적(semi-static)이거나 PDCCH (Physical Downlink Control Channel) 시그널링을 통해 동적일 수도 있다. In a sixth embodiment according to the principle of the present invention, it is proposed to include the RS overhead signal R_ovhd in a cell specific broadcast message or a UE specific radio resource control (RRC) message. Note that the cell specific broadcast message may be included in a primary BCH (broadcast channel) message or a dynamic BCH message (also known as SU). This means that for the k &lt;

May be added to the UE specific signaling of &lt; RTI ID = 0.0 &gt;

Signal is transmitted from the eNB), where UE specific signaling may be semi-static via RRC signaling or may be dynamic through PDCCH (Physical Downlink Control Channel) signaling.

레벨과, 모든 안테나들 및 모든 OFDM 심볼들에 걸친 T2P들의 계산 방법을 얻는다. 그리고 나서, UE는 얻은

와 P_B,K/P_RS를 이용하여, R_ovhd 값으로부터 디코딩된 T2P들을 계산하는 방법에 따라 서로 다른 안테나들 및 OFDM 심볼들에 걸친 모든 다른 T2P들을 계산한다.After receiving R_ovhd, the UE refers to the mapping table of R_ovhd (examples of these tables are shown in Table 6 through Table 8)

Level, and a calculation method of T2Ps over all antennas and all OFDM symbols. Then, the UE obtains

And all other T2Ps spanning different antennas and OFDM symbols according to the method of calculating T2Ps decoded from the R_ovhd value using P _{B, K} / P _RS .

그리고 상기 복수 개의 T2P 계산 방법들 중 선택된 계산 방법을 사용자 단말(220)로 할당한다. 안테나부(216)는 상기 맵핑 방식에 따라 상기 할당된 RS 오버헤드 비

와 상기 할당된 T2P 계산 방법 모두에 대응되는 오버헤드 신호와, 사용자 특정 T2P P_B,K/P_RS를 사용자 단말(220)로 전송한다. 유사하게, 도 7에 도시된 바와 같이, 사용자 단말(220)은 메모리부(224), 전력 설정부(226), 그리고 적어도 하나의 안테나를 포함하는 안테나부(222)로 구성된다. 안테나부(222)는 기지국(210)으로부터 오버헤드 신호 및 사용자 특정 T2P를 수신한다. 메모리부는 <표 1> 내지 <표 5>에 주어진 바와 같은 T2P를 계산하기 위한 복수 개의 방법들을 저장하고, <표 6> 내지 <표 8>에 주어진 바와 같은 복수 개의 오버헤드 신호들과, 복수 개의 RS 오버헤드 비들 및 복수 개의 T2P 계산 방법들 간의 맵핑 방식을 저장한다. 전력 설정부(226)는 수신된 RS 오버헤드 신호와 메모리부에 저장된 맵핑 방식에 의존하여 RS 오버헤드 비와 T2P 계산 방법을 결정하고, 수신된 T2P

와 RS 오버헤드 비 및 T2P 계산 방법에 의존하여 서로 다른 전송 안테나들 및 서로 다른 OFDM 심볼들에 걸친 T2P들을 계산한다.FIG. 7 schematically illustrates a wireless system including a base station (eNodeB) and a user terminal, according to an embodiment of the present invention. 7, the base station 210 includes a memory unit 212, a power setting unit 214, and an antenna unit 216 including at least one antenna. The memory unit 212 stores a plurality of methods for calculating T2Ps as given in Tables 1 to 5 and outputs a plurality of overhead signals as given in Tables 6 to 8, And a mapping scheme between a plurality of RS overhead ratios and a plurality of T2P calculation methods. The power setting unit 214 sets the user specific T2P P _{B, K} / P _RS , RS overhead ratio

And assigns the selected calculation method among the plurality of T2P calculation methods to the user terminal 220. [ The antenna unit 216 transmits the allocated RS overhead ratio

And an overhead signal corresponding to both the allocated T2P calculation method and the user-specific T2P P _{B and K} / P _RS to the user terminal 220. 7, the user terminal 220 includes a memory unit 224, a power setting unit 226, and an antenna unit 222 including at least one antenna. The antenna unit 222 receives the overhead signal and the user-specific T2P from the base station 210. The memory unit stores a plurality of methods for calculating the T2P as given in Tables 1 to 5 and includes a plurality of overhead signals as given in Tables 6 to 8, RS overhead ratio and a plurality of T2P calculation methods. The power setting unit 226 determines the RS overhead ratio and the T2P calculation method depending on the received RS overhead signal and the mapping method stored in the memory unit,

And the RS overhead ratio and the T2P calculation method to calculate T2Ps over different transmit antennas and different OFDM symbols.

및 복수 개의 T2P 계산 방법들 간의 맵핑 방식이 BS에서 설정되고 저장된다 (단계 312). 특정 OFDM 심볼들에 대한 사용자 특정 T2P

, RS 오버헤드 비

및 상기 복수 개의 T2P 계산 방법들 중 선택된 하나의 계산 방법이 사용자 단말의 유닛에 할당된다 (단계 314). 상기 맵핑 방식에 따라, 상기 할당된 RS 오버헤드 비

와 상기 할당된 T2P 계산 방법 모두에 대응되는 오버헤드 신호 R_ovhd가 결정된다 (단계 316). 사용자 특정 T2P

와 상기 오버헤드 신호 R_ovhd가 사용자 단말로 전송된다 (단계 318).FIG. 8 schematically shows a process of transmitting downlink power setting information in a base station (BS) according to an embodiment of the present invention. First, a plurality of methods for calculating T2Ps are set and stored in the BS (step 310). Then, a plurality of overhead signals R_ovhd, a plurality of RS overhead bids

And a mapping scheme between a plurality of T2P calculation methods are set and stored in the BS (step 312). A user-specific T2P for particular OFDM symbols

, RS overhead ratio

And a selected one of the plurality of T2P calculation methods is assigned to a unit of the user terminal (step 314). According to the mapping scheme, the allocated RS overhead ratio

And the overhead signal R_ovhd corresponding to both the assigned T2P calculation method are determined (step 316). User specific T2P

And the overhead signal R_ovhd are transmitted to the user terminal (step 318).

및 복수 개의 T2P 계산 방법들 간의 맵핑 방식이 UE에서 설정되고 저장된다 (단계 412). UE는 RS 오버헤드 신호와 특정 T2P

를 수신한다 (단계 414). UE는 상기 맵핑 방식에 의존하여 RS 오버헤드 비와 T2P들의 계산 방법 모두를 결정한다 (단계 416). UE는 수신된 T2P

와 결정된 RS 오버헤드 비 및 T2P 계산 방식에 의존하여 서로 다른 전송 안테나들 및 서로 다른 OFDM 심볼들에 걸친 T2P들을 계산한다 (단계 418).9 is a flowchart illustrating a process of calculating power setting information in a unit of a user terminal according to an embodiment of the present invention. First, a plurality of methods for calculating T2Ps are set and stored in the UE (step 410). Then, a plurality of overhead signals R_ovhd, a plurality of RS overhead bids

And a mapping scheme between a plurality of T2P calculation methods are set and stored in the UE (step 412). The UE transmits an RS overhead signal and a specific T2P

(Step 414). The UE determines both the RS overhead ratio and the calculation method of the T2Ps depending on the mapping scheme (step 416). The UE transmits the received T2P

(Step 418) T2Ps over different transmit antennas and different OFDM symbols, depending on the determined RS overhead ratio and the T2P computation scheme.

비 또는 UE 특정

비를 전송할 것을 제안한다. 이는 k번째 UE에 대한

의 UE 특정 시그널링에 추가되며, 이 UE 특정 시그널링은 RRC 시그널링을 통해 반정적이거나 PDCCH 시그널링을 통해 역동적일 수 있다. 이 경우, UE 측에서는, 모든 T2P들이 eNB로부터의 시그널링으로부터 직접 결정된다.In the seventh embodiment according to the principle of the present invention, for the k &lt; th &gt; UE,

Ratio or UE specific

It is proposed to transmit the rain. This means that for the k &lt;

UE specific signaling, which may be semi-static through RRC signaling or dynamic through PDCCH signaling. In this case, on the UE side, all T2Ps are determined directly from the signaling from the eNB.

In an eighth embodiment according to the principle of the present invention, the eNodeB determines a downlink transmission EPRE (Energy Per Resource Element).

The UE can assume that the downlink reference symbol EPRE is constant over the downlink system bandwidth and constant over all subframes until other RS power information is received.

가 P_A와 동일하다고 가정하며, 여기서 P_A는 3 비트를 이용하여 [3, 2, 1, 0, -1, -2, -3, -6]의 범위에서 상위 계층들에 의해 dB로 시그널링된 UE 특정 반정적 파라미터이다. For each UE, the PDSCH to RS EPRE ratios between PDSCH REs in all OFDM symbols not including RS are the same

Is assumed to be the same as the P _A, where P _A is signaled in dB by higher layers in the range of using the three bits [3, 2, 1, 0, -1, -2, -3, -6] UE specific anti-static parameters.

로 나타낸다. 셀 특정 비

는 상위 계층들에 의해 시그널링된 셀 특정 파라미터

와 구성된 eNodeB 셀 특정 안테나 포트들의 개수에 따라 하기 <표 9>와 같이 주어진다.For each UE, the PDSCH to RS EPRE ratio between PDSCH REs in all OFDM symbols including RS is the same

Respectively. Cell specific ratio

Lt; RTI ID = 0.0 &gt; cell-specific &lt; / RTI &

And the number of eNodeB cell-specific antenna ports configured as shown in Table 9 below.

For 16QAM or 64QAM PMCH, the UE can assume that the PMCH-to-RS EPRE ratio is 0 dB.

Note that in the above Table 9, the concept in <TS 36.213 version 8.3.0> is used. Table 10 summarizes the differences from the notation used in the original DOI, <Chairmen's note 2007, Jeju Island> and <TS 36.213 version 8.3.0>.

이고, 2개 또는 4개의 안테나의 경우

이다. 즉, 하나의 안테나의 경우

이고, 2개 또는 4개의 안테나의 경우

이다. 이제

가 1/6, 1/3, 3/6, 4/6라고 가정하면,하기 <표 11>로 요약되는

에 대한 해당 값들을 얻을 수 있다.Now, let us consider the above <Table 1> to <Table 3>. In Table 1 to Table 3, the second column is T2P for OFDM symbols including RS, and in the case of one antenna

, And for two or four antennas

to be. That is, in the case of one antenna

, And for two or four antennas

to be. now

Are 1/6, 1/3, 3/6, and 4/6,

Can be obtained.

= 1/6의 물리적 값을 시그널링하는 대신에, eNB는 간단히 P_B=0의 값을 UE에 시그널링할 수 있다. 이 경우, 이 신호 P_B=0 를 받는 즉시, UE는 <표 11>을 읽어 1Tx 경우

이고 2Tx 또는 4Tx 경우

라는 것을 알게 될 것이다.In Table 9 and Table 11, note that P _B is a parameter signaled from the eNB (base station) to the user terminal (UE). E.g,

= Instead of signaling a physical value of 1/6, the eNB can simply signal a value of P _B = 0 to the UE. In this case, upon receiving this signal P _B = 0, the UE reads <Table 11>

And 2Tx or 4Tx

You will know that.

이 명백히 <표 9>에는 나타나 있지 않지만, <표 9>의 각 행에 있는 모든 값들의 쌍들이 두 식, 즉 1Tx의 경우

(<표 1>의 왼쪽 열) 및 2/4Tx의 경우

(<표 2> 및 <표 3>의 왼쪽 열)의 관계에 따른다는 것을 알 수 있다. 특히, 이 2개 값들의 비들은, <표 9>의 각 행의

값들에서 알 수 있듯이, 항상

를 만족한다.Table 9 is compared with Table 1 to Table 3,

Is not explicitly shown in Table 9, but all pairs of values in each row of Table 9 are of two formulas: 1Tx

(Left column of Table 1) and 2 / 4Tx

(Left column of Table 2 and Table 3). In particular, the ratios of these two values are shown in Table 9,

As can be seen from the values,

.

The functions required to implement the present invention may be implemented in hardware, software, firmware or microcontrollers, microprocessors, digital signal processors, combinations thereof using programmable logic arrays, or any other suitable type of hardware, software, and / It can be implemented in whole or in part.

While the invention has been shown and described with respect to preferred embodiments thereof, it will be apparent to those skilled in the art that modifications and variations may be made without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (18)

A method for setting downlink transmission power by a wireless terminal in an OFDM (Orthogonal Frequency Division Multiplexing) system,
Obtaining a signaling parameter from a base station;
Based on the signaling parameters and the number of cell specific antenna ports provided in the base station, a first ratio of traffic data to pilot (T2P) for the first OFDM symbols and traffic data for the second OFDM symbols And a second ratio of the large pilot (T2P), the method comprising:
Wherein the ratio of the first ratio to the second ratio,
4/5, 3/5, and 2/5, respectively, when the signaling parameters are 0, 1, 2, and 3 for one cell-specific antenna port,
1, 3/4, 1/2 when the signaling parameters are 0, 1, 2, 3 for 2 or 4 cell specific antenna ports, respectively. The method according to claim 1,
The wireless terminal assumes that the Energy per Resource Element (EPRE) of the downlink reference symbol is constant over the downlink system bandwidth and all subframes until another reference signal (RS) power information is received Wherein the transmission power setting method comprises the steps of: The method according to claim 1,
Wherein the first ratio or the second ratio is the same for traffic data resource elements (REs) for each OFDM symbol. The method according to claim 1,
And the second ratio is obtained from the base station via an upper layer based on a UE-specific parameter. The method according to claim 1,
Wherein the first ratio is a ratio of a PDSCH EPRE and a cell specific RS EPRE among PDSCH REs of the first OFDM symbols including RS,
Wherein the second ratio is a ratio of a PDSCH EPRE and a cell specific RS EPRE of the PDSCH REs of the second OFDM symbols that do not include RSs. An apparatus in a wireless terminal for setting downlink transmission power in an OFDM system,
An antenna unit for receiving signaling parameters from the base station,
Based on the signaling parameters and the number of cell specific antenna ports provided at the base station, a first ratio of traffic data to pilot for the first OFDM symbols and a first ratio of traffic data to pilot for the second OFDM symbols And a power setting unit for determining a ratio between the first and second ratios,
Wherein the ratio of the first ratio to the second ratio,
4/5, 3/5, and 2/5, respectively, when the signaling parameters are 0, 1, 2, and 3 for one cell-specific antenna port,
1, 3/4, 1/2 when the signaling parameters are 0, 1, 2, 3 for 2 or 4 cell specific antenna ports, respectively. The method according to claim 6,
The power setting unit assumes that the energy per resource element (EPRE) of the downlink reference symbol is constant over the downlink system bandwidth and all subframes until another reference signal (RS) power information is received Lt; / RTI &gt; The method according to claim 6,
Wherein the first ratio or the second ratio is the same for traffic data resource elements (REs) for each OFDM symbol. The method according to claim 6,
Wherein the second ratio is obtained from the base station via an upper layer based on a UE-specific parameter. The method according to claim 6,
Wherein the first ratio is a ratio of a PDSCH EPRE and a cell specific RS EPRE among PDSCH REs of the first OFDM symbols including RS,
Wherein the second ratio is a beam of a PDSCH EPRE and a cell specific RS EPRE among the PDSCH REs of the second OFDM symbols not including the RS. A method for setting downlink transmission power by a base station in an OFDM system,
Transmitting a signaling parameter to wireless terminals in a cell,
The process of transmitting traffic data using either the first ratio of the traffic data to the first OFDM symbols and the second ratio of the traffic data to the second OFDM symbols is used. &Lt; / RTI &
Wherein a ratio between the first ratio and the second ratio is determined based on the signaling parameter and the number of cell specific antenna ports provided in the base station,
Wherein the ratio of the first ratio to the second ratio,
4/5, 3/5, and 2/5, respectively, when the signaling parameters are 0, 1, 2, and 3 for one cell-specific antenna port,
1, 3/4, 1/2 when the signaling parameters are 0, 1, 2, 3 for 2 or 4 cell specific antenna ports, respectively. 12. The method of claim 11,
Wherein the first ratio or the second ratio is the same for traffic data resource elements (REs) for each OFDM symbol. 12. The method of claim 11,
And transmitting a terminal-specific parameter used for determining the second ratio to each terminal in the cell through an upper layer. 12. The method of claim 11,
Wherein the first ratio is a ratio of a PDSCH EPRE and a cell specific RS EPRE among PDSCH REs of the first OFDM symbols including RS,
Wherein the second ratio is a ratio of a PDSCH EPRE and a cell specific RS EPRE of the PDSCH REs of the second OFDM symbols that do not include RSs. An apparatus in a base station for setting downlink transmission power in an OFDM system,
An antenna unit for transmitting signaling parameters to wireless terminals in the cell,
A transmitter that transmits traffic data using either a first ratio of traffic data to first OFDM symbols to a pilot and a second ratio of traffic data to pilot to second OFDM symbols, &Lt; / RTI &
Wherein a ratio between the first ratio and the second ratio is determined based on the signaling parameter and the number of cell specific antenna ports provided in the base station,
Wherein the ratio of the first ratio to the second ratio,
4/5, 3/5, and 2/5, respectively, when the signaling parameters are 0, 1, 2, and 3 for one cell-specific antenna port,
1, 3/4, 1/2 when the signaling parameters are 0, 1, 2, 3 for 2 or 4 cell specific antenna ports, respectively. 16. The method of claim 15,
Wherein the first ratio or the second ratio is the same for traffic data resource elements (REs) for each OFDM symbol. 16. The apparatus as claimed in claim 15, wherein the antenna unit transmits a terminal specific parameter used for determining the second ratio to each wireless terminal in the cell by an upper layer. 16. The method of claim 15,
Wherein the first ratio is a ratio of a PDSCH EPRE and a cell specific RS EPRE among PDSCH REs of the first OFDM symbols including RS,
Wherein the second ratio is a beam of a PDSCH EPRE and a cell specific RS EPRE among the PDSCH REs of the second OFDM symbols not including RS.

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