CN1146147C - Method for base station to guide mobile station to reduce prefix emitted power - Google Patents

Abstract

The present invention provides a method for a base station to transmit information by an acquisition indication channel to guide a mobile station to reduce prefix emitted power. The acquisition indication information is composed of an acquisition indicating (AI) part for indicating the mobile station to transmit information or continue to transmit a prefix and a power adjustment (PA) part which is connected to the acquisition indication (AI) part and used for indicating the mobile station to reduce prefix emitted power values. When acquisition indication which is transmitted by the base station and received by the mobile station is-1, the mobile station continues to demodulate the PA part to obtain an emitted power reduced value of the mobile station which transmits the next prefix.

Description

Translated fromChinese

一种由基站指示移动台减小前缀发射功率的方法A method for base station to instruct mobile station to reduce prefix transmission power

本发明涉及码分多址(CDMA)通信系统，说得更详细些，本发明涉及基站通过在捕获指示信道(acquisition indication channel，AICH)上发送的信息指示移动台减小前缀发射功率的方法。The present invention relates to a code division multiple access (CDMA) communication system. In more detail, the present invention relates to a method for a base station to instruct a mobile station to reduce the transmit power of a prefix through information sent on an acquisition indication channel (AICH).

在异步码分多址通信系统中，移动台首先通过小区搜索建立与小区的同步，然后在反向接入信道(reverse access channel，RACH)上发送前缀(preamble)，而基站在捕获指示信道上发送捕获指示(acquisition indication，AI)信息。其过程大致如下。In an asynchronous code division multiple access communication system, the mobile station first establishes synchronization with the cell through cell search, and then sends the preamble (preamble) on the reverse access channel (RACH), while the base station is on the acquisition indication channel Send acquisition indication (acquisition indication, AI) information. The process is roughly as follows.

移动台在小区的广播信道(broadcast channel，BCCH)上读取有关该小区的信息。所述信息包括：(1)该小区使用的前缀部分的扩频码/消息部分(message)的扰码；(2)可用的标记(signature)；(3)每种接入业务类别(access service category，ASC)的反向接入信道(RACH)的子信道组；(4)消息部分可用的扩频因子；(5)该小区中的上行链路的干扰电平；(6)主共用控制信道(common control principalchannel，CCPCH)；(7)捕获指示信道的传输定时；(8)前缀部分和消息部分的功率偏差ΔP_p-m；以及(9)功率偏移Δ₀(当没有收到捕获指示时的功率增加量)和ΔP₁(当收到捕获指示为-1时的功率减小量)。The mobile station reads information about the cell on a broadcast channel (broadcast channel, BCCH) of the cell. The information includes: (1) the spreading code of the prefix part used by the cell/scrambling code of the message part (message); (2) the available signature (signature); (3) each access service category (access service category, ASC) of the reverse access channel (RACH) subchannel group; (4) available spreading factor of the message part; (5) interference level of the uplink in the cell; (6) main sharing control channel (common control principal channel, CCPCH); (7) transmission timing of acquisition indication channel; (8) power deviation ΔP_pm of prefix part and message part; and (9) power deviation Δ₀ (when no acquisition indication is received power increase) and ΔP₁ (power decrease when an acquisition indication of -1 is received).

移动台在读取到小区信息后，首先从可用的扩频码中随机地选择一个前缀扩频码，并根据开环功率估计值将前缀的发射功率设置为P_RACH。移动台接着实行随机退避算法以从可用的ASC子信道组中选择一个RACH子信道，从而在选出的RACH子信道中得到在下两帧中的接入时隙(access slot，AS)。移动台再从可用的标记中随机地选择一个标记。移动台最后在得到的上行接入时隙，采用选出的标记，以设置的前缀发射功率发送前缀。After reading the cell information, the mobile station first randomly selects a prefix spreading code from the available spreading codes, and sets the transmit power of the prefix as P_RACH according to the estimated value of the open-loop power. The mobile station then performs a random backoff algorithm to select a RACH sub-channel from the available ASC sub-channel group, so as to obtain an access slot (AS) in the next two frames in the selected RACH sub-channel. The mobile station then randomly selects a token from the available tokens. Finally, in the obtained uplink access time slot, the mobile station uses the selected marker to transmit the prefix with the set prefix transmission power.

基站将在与上行接入时隙相对应的下行接入时隙通过AICH信道发送捕获指示。如果移动台在该下行接入时隙没有接收到捕获指示，则它将选择一个新的上行链路接入时隙，并把它的前缀发射功率增加ΔP₀；如果移动台在该下行接入时隙接收到的捕获指示为-1，则它将选择一个新的上行链路接入时隙，并把它的前缀发射功率减小ΔP₁；如果移动台在该下行接入时隙接收到的捕获指示为+1，则它将在发送完最后一个前缀的3或4个时隙之后发送消息。消息部分的发射功率相对于发送的最后一个前缀的功率要调整ΔP_p-m。The base station will send the acquisition indication through the AICH channel in the downlink access time slot corresponding to the uplink access time slot. If the mobile station does not receive an acquisition indication in the downlink access slot, it will select a new uplink access slot and increase its prefix transmission power by ΔP₀ ; if the mobile station in the downlink access slot If the acquisition indication received by the time slot is -1, it will select a new uplink access time slot and reduce its prefix transmit power by ΔP₁ ; if the mobile station receives If the capture indicator of the smack is +1, it will send the message 3 or 4 slots after the last prefix has been sent. The transmit power of the message part is adjusted by ΔP_pm relative to the power of the last prefix transmitted.

图1示出了第三代移动通信标准化组织(Third Generation Partnership Project，3GPP)规定的AICH帧的捕获指示信息的样式。两个AICH帧的长度为20ms，包含15个接入时隙，在每个时隙中包含有对一个移动台的捕获指示信息。捕获指示信息包括在前面的捕获指示部分(AI-part)和接在其后的空部分(empty-part)。前者长度为16个码元(4096个码片)，后者长度为4个码元(1024个码片)。Fig. 1 shows the style of the capture instruction information of the AICH frame stipulated by the third generation mobile communication standardization organization (Third Generation Partnership Project, 3GPP). The length of the two AICH frames is 20 ms, including 15 access time slots, and each time slot contains acquisition instruction information for a mobile station. The acquisition indication information includes an acquisition indication part (AI-part) preceding it and an empty part (empty-part) following it. The length of the former is 16 symbols (4096 chips), and the length of the latter is 4 symbols (1024 chips).

图2示出3GPP规定的捕获指示信息的产生方法。图中，W_i(i＝1，2，…，16)是16个正交的码字，AI_i(i＝1，2，…，16)是16个捕获指示，由开头16个码元构成AI部分，它是16个码字W_i(i＝1，2，…，16)乘以相应的捕获指示AI_i(i＝1，2，…，16)后对应的码元之和，而最后4个零码元构成空部分。FIG. 2 shows a method for generating acquisition indication information stipulated by 3GPP. In the figure, W_i (i=1, 2, ..., 16) are 16 orthogonal codewords, and AI_i (i = 1, 2, ..., 16) are 16 acquisition indications, consisting of the first 16 symbols Constitute the AI part, which is the sum of corresponding symbols after multiplying 16 codewords W_i (i=1, 2, ..., 16) by the corresponding acquisition indication AI_i (i = 1, 2, ..., 16), And the last 4 zero symbols constitute the empty part.

在现有技术中，移动台采用开环功率控制方式发送初始的前缀，即，移动台根据BCCH信道广播的BCCH发射功率估计出上行链路的路径损耗，它再根据BCCH信道上广播的上行链路的干扰电平确定上行前缀的发射功率。然而，当上行链路和下行链路的射频载波的频率相差较大时，这种开环功率估计的误差较大，从而使得移动台的初始的开环功率估计与基站要求接收的功率相差较大。这样，移动台接收到负的捕获指示后，要在新的上行时隙中重新发送前缀，其发射功率比前一次发送前缀的功率减小ΔP₁。当移动台的初始发射功率估计值过高，与基站要求接收的功率值相差较大时，一般移动台需多次减小前缀的发射功率才能达到目标值。换言之，移动台往往要在发送了数个前缀之后才能发送消息。这不仅降低了接入效率，浪费了系统资源，增加了对系统的干扰，还减小了系统的容量。In the prior art, the mobile station uses the open-loop power control method to send the initial prefix, that is, the mobile station estimates the uplink path loss according to the BCCH transmit power broadcast on the BCCH channel, and then it estimates the uplink path loss according to the uplink broadcast power on the BCCH channel. The interference level of the path determines the transmit power of the uplink prefix. However, when the frequencies of the uplink and downlink radio frequency carriers differ greatly, the error of this open-loop power estimation is large, so that the difference between the initial open-loop power estimation of the mobile station and the power required by the base station is relatively small. big. In this way, after the mobile station receives a negative acquisition indication, it needs to resend the preamble in a new uplink time slot, and its transmit power is reduced by ΔP₁ from the power of the previous sent preamble. When the estimated value of the initial transmission power of the mobile station is too high, which is quite different from the power value required by the base station, generally the mobile station needs to reduce the transmission power of the prefix several times to reach the target value. In other words, the mobile station often cannot send a message until several prefixes have been sent. This not only reduces access efficiency, wastes system resources, increases interference to the system, but also reduces system capacity.

本发明的目的在于克服现有技术中移动台需要多次减小发射功率才能达到目标值的缺点，从而在不增加系统资源的情况下，移动台不必多次发送前缀即可发送消息。The purpose of the present invention is to overcome the disadvantage in the prior art that the mobile station needs to reduce the transmission power multiple times to reach the target value, so that the mobile station can send messages without sending the prefix multiple times without increasing system resources.

本发明给出一种由基站通过AICH信道发送捕获信息指示移动台减小前缀发射功率的方法。采用本发明的方法，移动台首先根据接收到的小区信息设定前缀发射功率值，并且在反向接入信道上得到的上行接入时隙，采用选出的标记，以设定的功率值发送前缀；其次移动台在与上行接入时隙对应的下行接入时隙中接收基站经捕获指示信道发送的对于该移动台的捕获指示信息，最后移动台根据不同的情况作出不同的响应，其中，捕获指示信息由用于指示移动台发送消息或继续发送前缀的捕获指示部分和接于其后的用于指示移动台减小前缀发射功率值的功率调节(power adjustment，PA)部分构成。The invention provides a method for the base station to send capture information through the AICH channel to instruct the mobile station to reduce the transmission power of the prefix. Using the method of the present invention, the mobile station first sets the prefix transmission power value according to the received cell information, and the uplink access time slot obtained on the reverse access channel adopts the selected mark and uses the set power value Send the prefix; secondly, the mobile station receives the acquisition indication information for the mobile station sent by the base station through the acquisition indication channel in the downlink access time slot corresponding to the uplink access time slot, and finally the mobile station makes different responses according to different situations, Wherein, the acquisition indication information is composed of an acquisition indication part for instructing the mobile station to send a message or continue to send a prefix, followed by a power adjustment (power adjustment, PA) part for instructing the mobile station to reduce the transmission power value of the prefix.

下面，将结合附图详细介绍本发明的方法。在这些附图中：Next, the method of the present invention will be described in detail with reference to the accompanying drawings. In these drawings:

图1示出3GPP规定的捕获指示信息的样式；Fig. 1 shows the style of the acquisition indication information stipulated by 3GPP;

图2示出3GPP规定的捕获指示信息的产生方法；FIG. 2 shows a method for generating acquisition indication information specified by 3GPP;

图3是本发明提出的捕获指示信息的样式；Fig. 3 is the style of the capture instruction information proposed by the present invention;

图4是本发明提出的功率调节信号的第一种编码方法；Fig. 4 is the first coding method of the power adjustment signal proposed by the present invention;

图5是本发明提出的功率调节信号的第二种编码方法；Fig. 5 is the second coding method of the power adjustment signal proposed by the present invention;

图6是本发明的捕获指示信息的样式的实例；Fig. 6 is an example of the style of capture indication information of the present invention;

图7是本发明的功率调节信号的第一种编码方法的实例；以及Fig. 7 is the example of the first coding method of the power regulation signal of the present invention; And

图8是本发明的功率调节信号的第二种编码方法的实例。Fig. 8 is an example of the second encoding method of the power adjustment signal of the present invention.

现在参见图3，该图示出了本发明提出的捕获指示信息的样式。由图3可见，经AICH信道发送的捕获指示帧为两帧，长度为T(ms)，包含L个接入时隙。在每个接入时隙内的捕获指示信息包含捕获指示(AI)部分和功率调节(PA)部分。AI部分的长度为M₁个码片，包含N₁个码元。这里，N₁是移动台采用的标记的长度，它是2的整数次幂。AI部分的扩频因子为M₁/N₁。AI是N₁个正交的码字W_i(i＝1，2，…，N₁)乘以相应的捕获指示AI_i后对应的码元之和。PA部分的长度为M₂个码片，用于承载2比特的功率调节(PA)信息。当基站认为某个移动台的前缀发射功率过高时，就在对应的下行时隙先用AI部分的M₁个码片发送捕获指示-1，再用接于其后的PA部分的M₂个码片指示该移动台在发射随后的前缀时发射功率的减小值。下面列举两种方案及其相应的实例。Referring now to FIG. 3 , this figure shows the format of the capture indication information proposed by the present invention. It can be seen from FIG. 3 that the acquisition indication frame sent via the AICH channel is two frames, the length is T (ms), and includes L access slots. The acquisition indication information in each access slot contains an acquisition indication (AI) part and a power adjustment (PA) part. The AI part has a length of M₁ chips and contains N₁ symbols. Here,_N1 is the length of the mark used by the mobile station, which is an integer power of 2. The spreading factor of the AI part is M₁ /N₁ . AI is the sum of corresponding symbols after N₁ orthogonal codewords W_i (i=1, 2, ..., N₁ ) are multiplied by the corresponding acquisition indication AI_i . The length of the PA part is M₂ chips, and is used to carry 2-bit power adjustment (PA) information. When the base station thinks that the prefix transmission power of a certain mobile station is too high, it first uses the M₁ chips of the AI part to send the acquisition indication-1 in the corresponding downlink time slot, and then uses the subsequent M₂ chips of the PA part The chips indicate the reduction in transmit power for the mobile station when transmitting subsequent prefixes. Two schemes and their corresponding examples are listed below.

(方案1)(plan 1)

如图4所示，PA部分的M₂个码片包含2N₁个码元，每个码元的扩频因子SF＝M₂/2/N₁。这2N₁个码元是长度为N₁个码元的码字W_i(W_i1，W_i2，…，W_iN1)的两次重复。码字W_i与AI部分具有Ai_i＝-1的正交码字一致。这时，可以在这2N₁个码元上调制2比特的功率控制信息。即，如果AI部分的W_i(W_i1，W_i2，…，W_iN1)对应的捕获指示为-1，则在总长度为M₂个码片的两个码字W_iW_i是2比特的调制功率调节指示量b₀b₁，如果该量分别为00、01、10和11，则移动台将下一个前缀的发射功率分别减小ΔP₁、  2ΔP₁、3ΔP₁和4ΔP₁。对于移动台而言，如果解调其AI部分得到它相应的捕获指示为-1，则它还需继续解调后面的PA部分的M₂个码片，以获得PA信息。As shown in Fig. 4, the M₂ chips of the PA part include 2N₁ symbols, and the spreading factor of each symbol is SF=M₂ /2/N₁ . These 2N₁ symbols are two repetitions of a codeword W_i (W_i1 , W_i2 , . . . , W_iN1 ) of length N₁ symbols. The codeword W_i coincides with the orthogonal codeword with Ai_i =-1 for the AI part. At this time, 2-bit power control information can be modulated on these 2N₁ symbols. That is, if the acquisition indication corresponding to W_i (W_i1 , W_i2 ,...,W_iN1 ) of the AI part is -1, then the two codewords W_i W_i with a total length of M₂ chips are 2 bits The modulation power adjustment indication amount b₀ b_{1 of} , if the amount is 00, 01, 10 and 11 respectively, the mobile station will reduce the transmit power of the next prefix by ΔP₁ , 2ΔP₁ , 3ΔP₁ and 4ΔP₁ respectively. For the mobile station, if it demodulates its AI part and obtains its corresponding acquisition indication as -1, it needs to continue to demodulate the following M₂ chips of the PA part to obtain PA information.

(方案2)(Scenario 2)

如图5所示，PA部分的总长度为M₂个码片。用开头的M₂/2个码片调制第一个码元b₀，其扩频码采用长度为N₁个码片的标记的M₂/2/N₁次重复。用其后的M₂/2个码片调制第二个码元b₁，其扩频码采用长度为N₁个码片的标记的M₂/2/N₁次重复。这里，基站采用的标记与基站接收到的对应的移动台的标记相同。如果AI部分的W_i(W_i1，W_i2，…，W_iN1)对应的捕获指示为-1，则用总长度为M₂个码片调制功率调节指示量b₀b₁。如果该指示量分别为00、01、10和11，则移动台将在发送下一个前缀时把发射功率分别减小ΔP₁、2ΔP₁、3ΔP₁和4ΔP₁。对于移动台而言，如果解调其AI部分得到捕获指示为-1，则它还需继续解调后面的PA部分的M₂个码片，以获得PA信息。As shown in Figure 5, the total length of the PA part is M₂ chips. The first symbol b₀ is modulated with the first M₂ /2 chips, whose spreading code uses M₂ /2/N₁ repetitions of marks of length N₁ chips. The next M₂ /2 chips are used to modulate the second symbol b₁ , whose spreading code uses M₂ /2/N₁ repetitions of marks of length N₁ chips. Here, the signature adopted by the base station is the same as the signature of the corresponding mobile station received by the base station. If the acquisition indicator corresponding to W_i (W_i1 , W_i2 , ..., W_iN1 ) in the AI part is -1, then the power adjustment indicator b₀ b₁ is modulated with a total length of M₂ chips. If the indications are 00, 01, 10 and 11 respectively, the mobile station will reduce the transmission power by ΔP₁ , 2ΔP₁ , 3ΔP₁ and 4ΔP₁ when sending the next prefix. For the mobile station, if it demodulates its AI part and obtains an acquisition indication of -1, it needs to continue to demodulate the following M₂ chips of the PA part to obtain PA information.

下面给出本发明的实例。如图6所示，对于AICH帧、时隙等采取与3GPP规定相同的参数，即，AICH帧为两帧，共20ms，在两帧中共有15个接入时隙，每个接入时隙的AI部分为16个码元，共4096个码片，而PA部分为1024个码片。AI部分是16个正交的码字W_i(i＝1，2，…，16)乘以相应的捕获指示AI_i后对应码元的和，AI信号的扩频因子为256。当基站对某个移动台发送的标记返回的捕获指示为-1时，为了减少移动台重发前缀的次数，基站用接在AI信号后的PA信号的1024个码片来指示该移动台在随后发射前缀部分时将发射功率降低多少。下面分别叙述与上述的方案1和方案2对应的实例。Examples of the present invention are given below. As shown in Figure 6, the same parameters as those specified by 3GPP are adopted for the AICH frame and time slot, that is, the AICH frame is two frames, a total of 20 ms, and there are 15 access slots in the two frames, and each access slot The AI part is 16 code elements, a total of 4096 chips, while the PA part is 1024 chips. The AI part is the sum of corresponding symbols after multiplying 16 orthogonal codewords W_i (i=1, 2, ..., 16) by the corresponding acquisition indication AI_i , and the spreading factor of the AI signal is 256. When the base station returns an acquisition indication of -1 to the tag sent by a certain mobile station, in order to reduce the number of times the mobile station retransmits the prefix, the base station uses 1024 chips of the PA signal following the AI signal to indicate that the mobile station is How much to reduce the transmit power when the prefix portion is subsequently transmitted. Examples corresponding to theabove scheme 1 andscheme 2 are described below respectively.

(实例1)(Example 1)

如图7所示，PA信号的1024个码片对应32个码元，故其扩频因子为32。这32个码元是长度为16个码元的码字W_i(W_i1，W_i2，…，W_i16)两次重复。该码字与AI信号的具有Ai_i＝-1的正交码字相一致。这时，可在此32个码元上调制2比特的功率调节指示量b₀b₁。如果该指示量分别为00、01、10和11，则移动台将在发送下一个前缀时把发射功率分别减小ΔP₁、2ΔP₁、3ΔP₁和4ΔP₁。对于移动台而言，如果解调其AI部分的16个码元得到它相应的捕获指示为-1，则它还需继续解调接在其后面的PA部分的1024个码片，以获得功率调节信息。As shown in Figure 7, 1024 chips of the PA signal correspond to 32 symbols, so its spreading factor is 32. These 32 symbols are two repetitions of a codeword W_i (W_i1 , W_i2 , . . . , W_i16 ) of length 16 symbols. This codeword agrees with the orthogonal codeword of the AI signal with Ai_i =-1. At this time, the 2-bit power adjustment indicator b₀ b₁ can be modulated on the 32 symbols. If the indications are 00, 01, 10 and 11 respectively, the mobile station will reduce the transmission power by ΔP₁ , 2ΔP₁ , 3ΔP₁ and 4ΔP₁ when sending the next prefix. For the mobile station, if it demodulates the 16 symbols of its AI part and gets its corresponding acquisition indication as -1, it needs to continue to demodulate the 1024 chips of the PA part following it to obtain the power Regulatory information.

(实例2)(Example 2)

如图8所示，用PA部分的1024个码片调制2个码元b₀b₁，即，用前512个码片调制第一个码元b₀，用后512个码片调制第二个码元b₁。其扩频码采用长度为16个码片的标记的32次重复。这里，基站采用的标记与基站接收到的对应的移动台发送的标记相同。如果AI部分的W_i(i＝1，2，…，16)对应的捕获指示为-1，则在PA部分的1024个码片中，调制功率调节指示量b₀b₁。如果该指示量分别为00、01、10和11，则移动台将在发送下一个前缀时把发射功率分别减小ΔP₁、2ΔP₁、3ΔP₁和4ΔP₁。对于移动台而言，如果解调其AI部分的16个码元得到它相应的捕获指示为-1，则它还需继续解调接在其后面的PA部分的1024个码片，以获得功率调节信息。As shown in Figure 8, 2 symbols b₀ b₁ are modulated with 1024 chips of the PA part, that is, thefirst symbol b 0 is modulated with the first 512 chips, and the second symbol b₀ is modulated with the last 512 chips. symbol b₁ . Its spreading code employs 32 repetitions of marks with a length of 16 chips. Here, the signature used by the base station is the same as the signature received by the base station and sent by the corresponding mobile station. If the acquisition indicator corresponding to W_i (i=1, 2, ..., 16) in the AI part is -1, then in the 1024 chips of the PA part, the modulation power adjustment indicator b₀ b₁ is modulated. If the indications are 00, 01, 10 and 11 respectively, the mobile station will reduce the transmission power by ΔP₁ , 2ΔP₁ , 3ΔP₁ and 4ΔP₁ when sending the next prefix. For the mobile station, if it demodulates the 16 symbols of its AI part and gets its corresponding acquisition indication as -1, it needs to continue to demodulate the 1024 chips of the PA part following it to obtain the power Regulatory information.

Claims (6)

Translated fromChinese

1.一种用于调节移动台之前缀发射功率的方法，其特征在于，所述方法包括下述步骤：1. A method for adjusting the prefix transmission power of a mobile station, characterized in that the method comprises the following steps:移动台根据接收到的小区信息，设定一前缀发射功率；The mobile station sets a prefix transmit power according to the received cell information;所述移动台在反向接入信道上得到的上行接入时隙，以设定的前缀发射功率，发送前缀；The mobile station sends the prefix with the set prefix transmission power in the uplink access time slot obtained on the reverse access channel;所述移动台在与所述上行接入时隙对应的下行接入时隙中，通过捕获指示信道接收来自基站的捕获指示信息，其中所述捕获指示信息包括捕获指示部分和功率调节部分，所述捕获指示部分具有指示增加发射功率、减少发射功率和保持发射功率之一的信息，所述功率调节部分包含了关于发射功率减小值的信息；The mobile station receives acquisition indication information from the base station through an acquisition indication channel in the downlink access time slot corresponding to the uplink access time slot, wherein the acquisition indication information includes an acquisition indication part and a power adjustment part, the The acquisition instruction part has information indicating one of increasing transmission power, reducing transmission power and maintaining transmission power, and the power adjustment part contains information about a transmission power reduction value;如果捕获指示部分指示减小所述前缀发射功率，那么所述移动台根据所述功率调节部分所包含的关于发射功率减小值的信息，减小所述前缀发射功率；以及If the acquisition indication part indicates to reduce the prefix transmission power, the mobile station reduces the prefix transmission power according to the information about the transmission power reduction value contained in the power adjustment part; and所述移动台在下一个上行时隙，以所述经减小的发射功率，重新发送前缀。The mobile station retransmits the prefix with the reduced transmission power in the next uplink time slot.2.如权利要求1所述的方法，其特征在于，还包括以下步骤：2. The method of claim 1, further comprising the steps of:如果所述移动台没有接收到所述捕获指示信息，则把所述前缀发射功率增加ΔP₀；If the mobile station does not receive the acquisition indication information, increase the prefix transmit power by ΔP₀ ;所述移动台在下一个上行接入时隙，以增加的前缀发射功率，重新发送所述前缀。The mobile station resends the prefix with increased prefix transmission power in the next uplink access time slot.3.如权利要求1或2所述的方法，其特征在于，还包括以下步骤：3. The method according to claim 1 or 2, further comprising the steps of:如果所述捕获指示部分表示保持发射功率，那么所述移动台在数个上行接入时隙后，发送消息。If the acquisition indication part indicates to keep the transmission power, then the mobile station sends a message after several uplink access time slots.4.如权利要求1所述的方法，其特征在于，所述捕获指示部分总共为M₁个码片，包含N₁个码元，所述功率调节部分总共为M₂个码片，包含2N₁个码元，当所述捕获指示部分的正交码字W_i(W_i1，W_i2，…，W_iN1)对应的捕获指示为-1时，所述功率调节部分的2N₁个码元是对长度为N₁个码元的码字的两次重复调制了2比特的功率调节指示量b₀b₁而得到的，其中所述码字与所述捕获指示部分的正交码字W_i(W_i1，W_i2，…，W_iN1)一致的。4. The method according to claim 1, wherein the acquisition indication part is M₁ chips in total, including N₁ symbols, and the power adjustment part is M₂ chips in total, including 2N₁ symbol, when the acquisition indication corresponding to the orthogonal codeword W_i (W_i1 , W_i2 , ..., W_iN1 ) of the acquisition indication part is -1, the 2N₁ symbols of the power adjustment part It is obtained by modulating a 2-bit power adjustment indicator b₀ b₁ for two repetitions of a codeword with a length of N₁ symbols, wherein the codeword and the orthogonal codeword W of the acquisition indicator part_i (W_i1 , W_i2 , . . . , W_iN1 ) are consistent.5.如权利要求1所述的方法，其特征在于，所述捕获指示部分总共为M₁个码片，包含N₁个码元，所述功率调节部分总共为M₂个码片，当所述捕获指示部分的码字W_i(W_i1，W_i2，…，W_iN1)对应的所述捕获指示为-1时，在所述功率调节部分的所述M₂个码片中调制了2比特的功率调节指示量b₀b₁，其中在前M₂/2个码片中调制了第一个码元b₀，在后M₂/2个码片中调制了第二个码元b₁，扩频码都采用长度为N₁个码片的标记的M₂/2/N₁次重复，所述基站在这里采用的所述标记与所述基站接收到的移动台的标记相同。5. The method according to claim 1, wherein the acquisition indication part is M₁ chips in total, including N₁ symbols, and the power adjustment part is M₂ chips in total, when the When the acquisition indication corresponding to the codeword W_i (W_i1 , W_i2 ,...,W_iN1 ) of the acquisition indication part is_-1 , 2 Bit power adjustment indicator b₀ b₁ where the first symbol b₀ is modulated in the first M₂ /2 chips and the second symbol b is modulated in the last M₂ /2 chips_1. The spreading codes all use M₂ /2/N₁ repetitions of a mark with a length of N₁ chips, and the mark used by the base station here is the same as the mark of the mobile station received by the base station.6.如权利要求4或5所述的方法，其特征在于，当所述功率调节指示量b₀b₁分别为00、01、10和11时，则所述移动台把所述下一个前缀的发射功率分别减小ΔP₁、2ΔP₁、3ΔP₁和4ΔP₁。6. The method according to claim 4 or 5, wherein when the power adjustment indication b₀ b₁ is 00, 01, 10 and 11 respectively, the mobile station sets the next prefix The transmit power of ΔP₁ , 2ΔP₁ , 3ΔP₁ and 4ΔP₁ is reduced respectively.

Images