WO2004045108A1

WO2004045108A1 - Method for implementing a function of closed loop transmitting diversity on the dedicated channel

Info

Publication number: WO2004045108A1
Application number: PCT/CN2003/000948
Authority: WO
Inventors: Gang Li; Hui Zhou; Hao Wang
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2002-11-11
Filing date: 2003-11-11
Publication date: 2004-05-27
Also published as: CN1278505C; CN1499756A; AU2003284799A1

Abstract

The present invention discloses a method for implementing a function of closed loop transmitting diversity on the dedicated channel, which comprises: decomposing the weighting factor of every antenna into a phase complex multiplication coefficient and a power offset term , obtaining the power offset value A&lowbar;dB by the conversion of power offset term, and said phase complex multiplication coefficient is the complex number of which both real part and imaginary part are ±1 or 0; phase-modulating the framing data by using the phase complex multiplication coefficient ; getting a power amplitude value by using said power offset value A&lowbar;dB, and then using the obtained power amplitude value, transmitting the phase-modulated framing data in step B via the corresponding antenna, thereby implementing the weighting function of closed loop weighting factor for downlink dedicated channel. According, this invention can simplify greatly the chip design, and satisfy preferably the accuracy requirement when occupying less the chip resource.

Description

Method for implementing dedicated channel closed-loop transmit diversity function

The present invention relates to the diversity transmission technology of a mobile communication system, and particularly to a method for implementing closed-loop transmission of a dedicated channel in a base station of a Wideband Code Division Multiple Access / Universal Mobile Telecommunication System (WCDMA UMTS). Diversity method. Background of the invention

The base station of a mobile communication system uses two types of transmit diversity to improve the performance of user data transmission, namely open-loop diversity and closed-loop diversity. When using closed-loop transmit diversity, the base station uses two antennas to transmit user information. The base station adjusts the antenna according to the feedback from the user equipment (UE, User Equipment), and the feedback bit (FBI, Feedback Information) of the UE is transmitted in the uplink dedicated physical control channel (DPCCH, Dedicated Physical Control Channel).

The closed-loop transmit diversity itself has two modes of operation. In mode 1, the feedback command of the UE controls the phase adjustment to maximize the power received by the UE, so the base station keeps the phase of antenna 1 unchanged, and adjusts the phase of antenna 2 according to the moving average of two consecutive feedback commands. Antenna 2 can use four different phase settings in this mode.

In mode 2, in addition to phase adjustment, there is also amplitude adjustment, but a four-bit feedback command is used. These four bits are located in four uplink DPCCH slots, one of which is an amplitude adjustment command and three are phase adjustment commands. In this way, there are eight different phases and two different amplitude combinations, and the base station's signal transmission has a total of 16 combinations.

Among them, closed-loop diversity is only applicable to dedicated channels and downlink shared channels (DSCH, Downlink Shared Channel) used with dedicated channels, and open-loop diversity can be used for both dedicated channels and common channels. The closed-loop diversity, closed-loop transmit diversity, and dedicated-channel closed-loop transmit diversity in this paper are the same concepts. The concepts of mode 1 and mode 2 have been described above. Among them, antenna 1 and antenna 2 can actually be called main antennas and diversity antennas. In the absence of diversity (open loop or closed loop), data is sent only through antenna 1, and there is no data on antenna 2. In the case of diversity, In addition to sending data from antenna 1, data is also sent from antenna 1.

In the downlink modulation of the dedicated channel of the WCDMA base station, the function of closed-loop transmit diversity needs to be implemented. The closed-loop transmit diversity function can be decomposed into three functions: weighting factor calculation, power / phase adjustment, and pilot pattern allocation. among them:

(1) The weighting factor calculation is based on the FBI information of the corresponding uplink dedicated physical channel (DPCH, Dedicated Physical Channel) sent by the demodulation frame, and the weighting factor of the current two antennas is calculated once per time slot. DPCH consists of DPCCH and Dedicated Physical Data Channel (DPDCH).

(2) The power / phase adjustment uses the calculated weighting factors, and each time slot performs a complex multiplication of the DPCH channel on the two antennas;

(3) PILOT pattern allocation means that in closed-loop diversity mode 1, the DPCH sends orthogonal pilot patterns on the two antennas, and in mode 2, the DPCH pilot patterns on the two antennas are the same.

Among them, the process of PILOT pattern allocation is relatively simple, but the work of calculating weighting factors and weighting the complex signals after spreading is more complicated. This is because the real and imaginary parts of the weighting factor are decimals in many cases, which makes it more difficult to perform complex multiplication.

The transmitter structure supporting DPCH closed-loop mode transmit diversity is shown in Figure 1. Among them, the channel coding, interleaving and spreading parts are all the same as the non-diversity mode. Multiplexed signal to spreading the two transmitting antennas, and the antenna-specific weighting factors _Wl and w ₂ weighting. In general, the weighting factor is a complex number, that is, \ ^ = + ^, and w ₂ correspond to the phase adjustment amount in the closed-loop mode 1 and the phase / amplitude adjustment amount in the closed-loop mode 2, respectively. The weighting factor is determined by the UE, and the D domain bit of the FBI field of the uplink DPCCH is used to notify the WCDMA base station. Closed-loop transmit diversity uses which of Mode 1 or Mode 2 is specified by higher layers. In mode 1, the weighted factors w ₂ are obtained by averaging the phases received in two time slots, and ^ is a constant. In mode 2, the phase information (FSM _ph ) is obtained from the FBI received in three time slots, and the power information (FSM _P. ) Is obtained from the FBI of one time slot, and the feedback notification information (FSM, Feedback) formed by the FBI is used. Signalling Message) to obtain the phase difference and the transmit power of the antenna, so as to calculate the weighting factor W ^ PW ₂ . There are some special cases for both modes, namely, frame tail adjustment, initialization and compression modes. The following are specific operations in each case.

(1) End of frame adjustment

At the end of each frame, for mode 1, when the FBI of time slot (Slot) 0 is received, it is not combined with the FBI of time slot 14 of the previous frame, but with time slot 13 of the previous frame; for mode 2. The last FSM of each frame has only three FSM _ph bits, and no FSM _P. Bit, power adjustment still uses the information from the previous FSM.

(2) Initialization of closed-loop diversity

After the uplink DPCH is established (at this time, the downlink DPCH has been established), the UE starts to send the FBI from SlotO, and the base station only receives the FBI of SlotO in mode 1. In mode 2, when the three-bit FSM _ph is not received, press Table 3 initializes the phase and does not receive a one-bit FSM _P. At that time, 0.5 is used as the transmitting power of the antenna.

(3) Compression mode recovery period of closed-loop diversity mode 2

If the FSM resumes sending at exactly 0, 4, 8, 12 in the uplink time slot, then initialization is performed; if the FSM resumes sending at other time slots, the first bit of the FSM _ph is always sent in the current incomplete FSM cycle, and The power of the two antennas is set to be equal; initialization is performed until a new FSM cycle arrives.

For mode 1, there is only phase information, so a 2-bit FSM is needed to calculate the weighting factor. Table 1 shows the relationship between the feedback instruction FBI and the i-th slot adjustment amount of the uplink radio frame. From Table 1, the phase adjustment amount can be obtained according to the FSM. FSMph 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14

0 0 π / 2 0 π / 2 0 π / 2 0 π / 2 0 π / 2 0 π / 2 0 π / 2 0

1 π-π / π -π / π-π / π-π / π-π / π -π / π 1 / π

2 2 2 2 2 2 2

Table 1

Then calculate the weighting factor of antenna 2 by the following formula (1),

Σcos (^) Σsin (^.)

w-, = '' ■ + j

( 1 )

^ t. ^ e {θ, π, π 12, -π 1 2] The weighting factor of antenna 1 is constant: ^w i ^{= 1 /}

For mode 2, it is determined by its FSM _P. , FSM _ph calculates the transmit power (power_antl, power_ant2) and phase difference (phase_diff) of the two antennas, respectively.

Table 2 shows the FSM _P of the closed-loop mode 2 signaling message. Correspondence with transmit power. Table 3 shows the correspondence between the FSM _ph subfield of the closed-loop mode 2 signaling message and the phase difference between the antennas.

FSM _{ph Phase} difference between two antennas (°)

000 180

001 -135

011 -90

010 -45

110 0

111 45

101 90

100 135 After obtaining the transmission power of the antenna power- antl, power_ant2 phase and phase- diff, a weighting factor W is calculated by the following equation ₍₂₎ ^ PW 2. power _ antl

w:

power _ antl exp (y phase― diff)

Writing (2) Equation (2) is a vector representation, _{Wl of the} top row indicates, represents the lower row w _2.

A common design method is to use a register to store the value after the integer squared according to the design accuracy requirements. The value includes the decimal part, and the register is used to indicate the number of decimal places. Since the weighting factor calculated by closed-loop transmit diversity needs to be multiplied with the coded data after spreading, such a design method becomes more complicated when performing complex multiplication. Not only is the amount of calculations extremely large, but it also consumes a lot of resources.

As can be seen from the calculation formula of the closed-loop diversity weighting factor, the general form of the complex weighting factor is Aexp (j phase_diff). According to the value of the phase difference, the weighting factor may be A,-A, Aj,-Aj, 2 ^{-1 2} A (1 + j), 2- ^{1 2} A (l -j), 2- ^1/2 A (-1 + j), ^2-1/2 A (-1-j). The values of A are 0.5 ^1/2 , 0.2 ^1/2, and 0.8 ^{1 2} . Multiplying these complex weighting factors and spread-spectrum data directly consumes a large amount of chip resources and is difficult to implement. Summary of the invention

In view of this, the main object of the present invention is to provide a method for implementing a dedicated channel closed-loop transmit diversity function, so as to reduce calculation complexity and reduce occupation of system resources.

The present invention provides a method for implementing a dedicated channel closed-loop transmit diversity function. The method separately calculates the weighting factors of the antenna 1 and the antenna 2 according to the feedback information of the mobile terminal, and further includes: A. The weighting factor of each antenna is decomposed into a phase complex multiplication coefficient and a power offset term, and the power offset term is converted to obtain a power offset A_dB. The phase complex multiplication coefficients are both real and imaginary parts ± 1 Or a plural of 0;

B. Use the phase complex multiplication coefficient to phase adjust the framing data;

C. Use the power offset A-dB to obtain a power amplitude value, and then use the obtained power amplitude value to transmit the framed data after the phase adjustment in step B on the corresponding antenna.

The power offset in step A can be obtained by taking the log of the power offset and multiplying by 20.

Obtaining the power amplitude value in step C may be obtained by subtracting the power offset A-dB from the power dB value calculated by the power control module, and then checking the power quantization table by using the difference between the two.

When the power offset terms in step A are 0.5 ^1/2 and 0.8 ^{1 2} , the power offsets A-dB are -3.01 dB and -0.97 dB, respectively.

Step A power offset is a power offset term and taken to give the product of 2 ^n, and then multiplied by the number of 20, wherein n is an integer;

Obtaining the corresponding power amplitude value in step C is to subtract the power offset A-dB from the power dB value calculated by the power control module, and use the difference between the two to check the power quantization table to obtain the corresponding power amplitude value. , And then right-shift the power amplitude value by n bits.

When the power offset term in step A is 0.2 ^1/2 , the power offset A-dB is -0.97dB, and n is 1.

The phase multiplication coefficient corresponding to the weighting factor of antenna 1 in step A is zero.

Step B can include:

Bl. Binary encode all possible values of the phase complex multiplication coefficient, and all possible values are determined based on all complex numbers with real and imaginary parts of ± 1 or 0, a total of eight types;

B2. Binary encoding the framing data and all possible values of the phase complex multiplication coefficient into Performing multiplication operations to get eight results;

B3. The real part of the eight results is sequentially input to a first multi-selector, and the imaginary part is sequentially input to a second multi-selector. The multi-selector is an eight-select one-selector.

B4. Use the phase multiplication coefficient obtained in step A as the selection signal of the first and second multi selectors, and use the data output by the first multi selector as the real part, and the data output by the second multi selector. Is the imaginary part, and the complex number of the combination of the real part and the imaginary part is taken as a result of the complex multiplication operation of the phase complex multiplication coefficient and the framing data to complete the phase adjustment of the framing data.

The invention adopts a new type of fixed-point optimization algorithm as the key technology of the closed-loop transmit diversity implementation scheme, and solves the problems existing in the prior art well. According to the characteristics of the closed-loop transmit diversity weighting factor, the weighting factor is decomposed into three parts: phase complex multiplication coefficient, power offset, and right shift number; correspondingly, the complex coefficient weighted multiplication is also decomposed into a multi-selector and power quantization. Table offset and shift operations are performed in three parts to achieve phase adjustment and power adjustment, and finally realize the weighting effect of the closed-loop diversity weighting factor on downlink dedicated channel data. This greatly simplifies the chip design and satisfies the accuracy requirements while occupying less chip resources. Compared with the prior art, the method of the present invention has the following advantages:

(1) In the prior art, a complex weighting factor is directly used as the calculation result of the closed-loop transmit diversity. Not only is the hardware implementation complicated, it occupies more resources, but it also affects the modulation power control of the WCDMA downlink dedicated channel. Optimized decomposition, which is not only simple to implement, but also convenient for power control of dedicated physical channels;

(2) Since the downlink shared channel adopts the weighting factor of closed-loop transmit diversity that accompanies the dedicated channel, the algorithm using the complex weighting factor of the closed-loop transmit diversity of the downlink dedicated channel also simplifies the implementation of the closed-loop transmit diversity function of the downlink shared channel, which is easy Realize the power control process of the downlink shared channel. Brief description of the drawings

FIG. 1 is a schematic diagram of a closed-loop transmit diversity function in the prior art;

FIG. 2 is a schematic diagram of the phase adjustment of the antenna 2 in the present invention. Mode of Carrying Out the Invention

The following describes the specific implementation method of the closed-loop transmit diversity in the present invention:

The complex weighting factors for both Mode 1 and Mode 2 can be factored into three parts:

(a) Phase complex multiplication factor: A complex number C with real and imaginary parts of ± 1 or 0;

(b) a power offset term: a 2- ^1/2 - A decimal between 2 ^1/2;

c) Right shift number: Determined by reduction factor l / 2 ⁿ .

These three parts adopt different implementation methods:

(1) When the real and imaginary parts are complex numbers of ± 1 or 0, and when the complex multiplication is performed with the data after framing, considering the speciality of the multiplier, the adder and the selector can be implemented, as shown in Figure 2;

(2) In order to avoid a wide multiplication operation, the implementation method of multiplying by a decimal A is as follows: Convert A into the decibel number A—dB (then -3.01dB <A— dB 3.01dB), check the power quantization in the power control module Before the table, subtract the offset A- dB from the power dB value. When WCDMA downlink physical channel modulation implements channel power weighting, it is necessary to look up the power quantization table to obtain the channel power amplitude value according to the channel power dB value. Therefore, the implementation of the above-mentioned decimal A can be completed together during the table lookup operation, and only takes up little Additional resources. And by extracting l / 2 ⁿ to make A between 0.5-1, so as to improve the calculation accuracy.

(3) The method of multiplying by l / 2 ⁿ is to right-shift n bits as needed at the end of the power control module. Of course, if the power offset term is not increased by 1/2 ⁿ times, the right shift number n does not exist.

The weighting factor decomposition of mode 1 is relatively simple. The weighting factor \ ^ of antenna 1 is a constant. After taking the logarithm, the power offset is -3.01dB. The weighting factor w _{2 of} antenna 2 is calculated by formula (1). There are four This value is determined by the value of the 2-bit FSM instruction. Day The weighting factor of line 2 can be decomposed into two parts: the right shift number and the phase multiplication factor. The decomposition of the weighting factors of antenna 1 and antenna 2 in the whole mode 1 is shown in Table 4. It can be seen from Table 4 that antenna 2 The weighting factor is nothing more than (l + j) / 2, (lj) / 2, (-l + j) / 2,-(l + j) / 2, because dividing by 2 is equivalent to the data stored in the register. Shift by one bit, so it can be decomposed into right shift number and phase complex coefficient.

Table 4

The calculation of the weighting factor for Mode 2 is based on the FSM instruction to look up Table 2 and Table 3 to obtain the transmission power and phase difference. The decomposition is more complicated, as shown in Table 5. The item of weighting coefficient in Table 5 is to look up Table 2 and Table 3 according to the FSM instruction, and calculate the weighting factor of Mode 2 by formula 2. It can be divided into two cases: antenna 1 and antenna 2.

The value of the weighting factor of antenna 1 is very simple, and it is the three decimal roots of 0.2, 0.5, or 0.8. Among them, 0.8 ^1/2 and 0.5 ^{1 2} take 201og operation to get -0.97dB, which is 20 χ log 0.8 ^{1 2} =-. 97 and 3.01dB, that is, 20><log0.5 ^1/2 = -3.01, and 0.2 ^{1 / 2} takes the logarithmic operation value too small, so multiply by 2 first, and then take the logarithmic operation to get -0.97dB, which is 20 x log (2 0.2 ^1/2 ) =-0.97, and its right shift number accordingly. Set to 1 to ensure the original value is restored. In addition to the fractional square root, the weighting factor of antenna 2 is also multiplied by the phase adjustment amount, so it can finally be decomposed into three parts: the phase multiplication coefficient, the right shift number, and the power offset.

The weighting factor for mode 2 is composed of a 3-bit FSM _ph and a 1-bit FSM _P. A total of 4 bits of FSM instructions are calculated, and mode 1 only requires 2 bits of FSM instructions. The correspondence between these FSM instructions and the parameters of antenna 1 and antenna 2 is also shown in Table 5. Table 5 shows the decomposition of the weighting factor for Mode 2.

table 5

It can be seen from Table 5 that in the case of the mode 2, the weighting factor _{W1 of the} antenna 1 can be decomposed into two parts: a power offset and a right shift number. The specific values of these two parts are related to the FSM instruction. The weighting factor w _{2 of the} antenna 2 can be decomposed into three parts: a power offset, a right shift number, and a phase complex multiplication factor. Their values are also determined by the value of the FSM. Regardless of mode 1 or mode 2, the weighting factor of antenna 2 will form a complex number C with real and imaginary parts of ± 1 or 0. When the complex number C is multiplied with the framed data, the framed data will be changed. Phase, so the complex number C can be called a phase complex multiplication coefficient. Assume that the framing data is represented by I + jQ, where I represents the real part and Q represents the imaginary part. Considering the various values of the phase complex multiplication coefficient, the result of the complex multiplication operation of the frame data and the phase complex multiplication coefficient is only 8 possibilities. For ease of implementation, the phase complex multiplication coefficient is encoded as a phase selection signal, and the phase selection signal starts from 0 and goes to 7 and is expressed in binary. Table 6 shows the correspondence table between the phase multiplication coefficients and the selection signals.

Table 6

According to the relationship between the phase selection signal and the complex multiplication operation result in Table 6, the phase adjustment circuits of the I and Q data can be conveniently implemented, as shown in FIG. As can be seen from the figure, the output I data after phase adjustment are I, -I, -Q, Q, I + Q,-(I + Q), QI, IQ, corresponding to the complex multiplication operation results in Table 6. The real part of the output Q after phase adjustment is Q, -Q, I, -1, QI, IQ, I + Q,-(I + Q) 'corresponds to the imaginary part of the complex multiplication result in Table 6. . Since the antenna 2 has a phase complex multiplication coefficient, only the antenna 2 needs to perform the phase adjustment operation.

In the present invention, after the weighting factors of Mode 1 and Mode 2 are decomposed, a decimal A bounded between 2 ^1/2 and 2 ^1/2 will be formed. The decimal A is converted into a value in dB by taking a logarithmic operation. A_dB, called the power offset, works with the right shift number n on the power control module in the downlink dedicated channel modulation. In the downlink dedicated channel modulation process, the encoded data passes through the physical After framing, spreading is performed according to the channelization code, and then multiplication is performed with the scrambling code to obtain the scrambled data. Finally, the power output by the power control module modulates and outputs the scrambled data. Therefore, power control is also an important functional point in downlink dedicated channel modulation. In the power control module, the inner loop power control, limited power growth, and power balancing are mainly implemented. The output of the power control will directly affect the scrambled data of the dedicated channel. Therefore, after the power control module calculates the specific power dB value of each domain of the dedicated channel, it needs to subtract the power offset A_dB of the closed-loop diversity, and then check the power quantization table to obtain the corresponding power amplitude value. The right shift number is used to shift the power amplitude value to achieve the weighting effect of the closed-loop diversity weighting factor on the downlink dedicated channel data.

In summary, according to the characteristics of the closed-loop transmit diversity weighting factor, the present invention decomposes the weighting factor into three parts: a phase complex multiplication coefficient C, a power offset A-dB, and a right shift number n; accordingly, the complex coefficient weighted multiplication It is also decomposed into three parts of multi-selector, power quantization table shift and shift operation, which greatly simplifies the chip design. This algorithm also satisfies the accuracy requirements while occupying less chip resources.

Table 7 is a power quantization table used in the present invention. In the method of the present invention, the power is obtained by looking up Table 7, which includes the power address value (that is, the power dB value mentioned above) and the corresponding value. In order to express the value intuitively, the power amplitude value is expressed in decimal here, but in actual operation, the power amplitude value expressed in binary is used. In specific use, the power amplitude value is multiplied with the data to be transmitted, and then transmitted through the antenna. The power amplitude value determines the energy of the transmitted data. As can be seen from Table 7, the larger the power address value, the smaller the power amplitude value, and vice versa. When there is no transmit diversity, only antenna 1 sends data. When there is transmit diversity, both antenna 1 and antenna 2 send data. Therefore, the power of both antennas is required to decrease. This refers to the power amplitude value, so that there is only one antenna at the same time. The power when transmitting is the same. The decrease of the power amplitude value requires the increase of the power address value, so in this sense, an offset must be added to the power address value. A-dB is a negative number, so subtracting this negative number can achieve the effect of "plus", that is, the effect of increasing the power address value and reducing the power amplitude value. Power power power power power power power power power power power power power address power value power value power value power value power value power value

1 7,607 46 2,083 91 570 136 156

2 7,392 47 2,024 92 554 137 152

3 7,182 48 1,967 93 539 138 147

4 6,978 49 1,911 94 523 139 143

5 6,780 50 1,857 95 508 140 139

6 6,588 51 1,804 96 494 141 135

7 6,401 52 1,753 97 480 142 131

8 6,219 53 1,703 98 466 143 128

9 6,043 54 1,655 99 453 144 124

10 5,871 55 1,608 100 440 145 121

11 5,705 56 1,562 101 428 146 117

12 5,543 57 1,518 102 416 147 114

13 5,386 58 1,475 103 404 148 111

14 5,233 59 1,433 104 392 149 107

15 5,084 60 1,392 105 381 150 104

16 4,940 61 1,353 106 370 151 101

17 4,800 62 1,314 107 360 152 99

18 4,664 63 1,277 108 350 153 96

19 4,531 64 1,241 109 340 154 93

20 4,403 65 1,206 110 330 155 90

21 4,278 66 1,171 111 321 156 88

22 4,157 67 1,138 112 312 157 85

23 4,039 68 1,106 113 303 158 83

24 3,924 69 1,075 114 294 159 81

25 3,813 70 1,044 115 286 160 78

26 3,705 71 1,014 116 278 161 76

27 3,599 72 986 117 270 162 74

28 3,497 73 958 118 262 163 72

29 3,398 74 931 119 255 164 70

30 3,302 75 904 120 248 165 68

31 3,208 76 878 121 241 166 66

32 3,117 77 854 122 234 167 64

33 3,029 78 829 123 227 168 62

34 2,943 79 806 124 221 169 60

35 2,859 80 783 125 214 170 59

36 2,778 81 761 126 208 171 57

37 2,699 82 739 127 202 172 55

38 2,623 83 718 128 197 173 54

39 2,548 84 698 129 191 174 52 40 2,476 85 678 130 186 175 51

41 2,406 86 659 131 180 176 49

42 2,337 87 640 132 175 177 48

43 2,271 88 622 133 170 178

44 2,207 89 604 134 165 179

45 2,144 90 587 135 161 180

Table 7

In the present invention, except for the uplink dedicated physical channel specifically indicated, the default dedicated channel refers to the downlink dedicated physical channel. The so-called uplink is from the UE to the base station, and the downlink is from the base station to the UE.

The uplink DPCH is divided into DPDCH and DPCCH. DPDCH transmits data and DPCCH transmits control information. The DPCCH has an FBI field, which is used to notify the base station to adjust the phase or amplitude. Each frame of the uplink dedicated physical channel is 10 ms long and is divided into 15 time slots, and the length of each time slot is T _sl . _t = 2560 chips, corresponding to one power control cycle.

The downlink DPCH is also divided into DPDCH and DPCCH. DPDCH transmits data and DPCCH transmits control information. DPCCH has three domains: TPC, TFCI and Pilot. Each 10ms frame of the downlink dedicated physical channel is divided into 15 time slots, each time slot is Tslot = 2560 chips, corresponding to a power control cycle.

Claims

Claim

1. A method for implementing a dedicated channel closed-loop transmit diversity function, wherein the feedback information of the mobile terminal is used to calculate the weighting factors of antenna 1 and antenna 2, respectively, and the method further includes the following steps:

A. The weighting factor of each antenna is decomposed into a phase complex multiplication coefficient and a power offset term, and the power offset term is converted to obtain a power offset A-dB. The phase complex multiplication coefficients are both real and imaginary parts. Complex numbers of 1 or 0;

2. The method according to claim 1, wherein the power offset amount in step A is obtained by multiplying a logarithm of the power offset term by 20.

3. The method according to claim 2, wherein the step of obtaining the power amplitude value in step C is to subtract the power offset value A-dB from the power dB value calculated by the power control module, and then use two The difference between the two is obtained by checking the power quantization table.

4. The method according to claim 2, wherein, when the power offset terms in step A are 0.5 ^{1 2} and 0.8 ^1/2 , the power offsets A-dB are -3.01 dB and- 0.97dB.

5. The method of claim 1, wherein said step A power offset is a power offset term and the product of 2 ^n, the logarithm multiplied by 20 and then, where n is an integer ; The corresponding power amplitude value obtained in step C is obtained by subtracting the power offset value calculated by the power control module from the power dB value into _ (18, using the difference between the two to check the power quantization table to obtain the corresponding power. Amplitude value, and then right-shift the power amplitude value by n bits.

6. The method according to claim 5, wherein the power in step A When the offset term is 0.2 ^1/2 , the power offset A-dB is -0.97dB, and n is 1.

7. The method according to claim 1, wherein the phase complex multiplication coefficient corresponding to the weighting factor of antenna 1 in step A is 0.

8. The method according to claim 1, wherein step B comprises:

Bl. Binary encode all possible values of the phase complex multiplication coefficient. All possible values are determined based on all complex numbers based on the actual value and the imaginary part is ± 1 or 0. There are eight types;

B2: Perform a multiplication operation on the binary encoding of the framing data and all possible values of the phase multiplication coefficient to obtain eight results;