CN106571891A - Fountain multiple access method - Google Patents

本发明公开了一种喷泉多址接入方法，该方法中发送端喷泉译码器为增量译码器，用度分布相同，生成矩阵不同的喷泉码来区分多用户；每个用户用相同的交织器对编码序列比特交织后调制发送出去；接收端先对接收信号解调和解交织，然后对解交织后的数据采用喷泉多用户迭代检测方法进行译码。本发明喷泉多址接入方法，不管用户数有多少、多址干扰多严重、信道条件多恶劣，总可以通过增加开销完成正确译码，因此具有很强的自适应能力。此外，用户间发送信号不用同步，可以异步发送。

The invention discloses a fountain multiple access method. In the method, the fountain decoder at the sending end is an incremental decoder, which uses fountain codes with the same degree distribution and different generation matrices to distinguish multiple users; each user uses the same The interleaver interleaves the coded sequence bits and then modulates and sends them out; the receiving end first demodulates and deinterleaves the received signal, and then decodes the deinterleaved data by using the fountain multi-user iterative detection method. No matter how many users there are, how serious the multiple access interference is, and how bad the channel conditions are, the fountain multiple access method of the present invention can always complete correct decoding by increasing overhead, so it has strong self-adaptive ability. In addition, the signals sent between users do not need to be synchronized, but can be sent asynchronously.

一种喷泉多址接入方法A Fountain Multiple Access Method

技术领域technical field

本发明涉及一种多址接入方法，具体涉及一种基于喷泉码的多址接入方法，属于无线通信技术领域。The invention relates to a multiple access method, in particular to a fountain code-based multiple access method, and belongs to the technical field of wireless communication.

背景技术Background technique

传统的码分多址(CDMA)系统主要通过相互正交的扩频序列来区分不同的用户，由于实际使用的扩频码很难做到严格正交和严格同步，导致了多址干扰(MAI)的产生，严重影响了接受性能与系统容量。且扩频码专门设计，所以不能满足用户量爆发式增长的需求。近来，非正交多址技术因其支持用户数量大而被广泛研究。常见的非正交多址包括功率多址、稀疏码多址、滤波器多址、图样分割多址、多用户共享多址、喷泉多址等。The traditional code division multiple access (CDMA) system mainly distinguishes different users through mutually orthogonal spreading sequences. Since the actually used spreading codes are difficult to achieve strict orthogonality and strict synchronization, resulting in multiple access interference (MAI ) has seriously affected the acceptance performance and system capacity. Moreover, the spreading code is specially designed, so it cannot meet the demand for explosive growth of the number of users. Recently, non-orthogonal multiple access technology has been extensively studied because of its support for a large number of users. Common non-orthogonal multiple access includes power multiple access, sparse code multiple access, filter multiple access, pattern division multiple access, multi-user shared multiple access, fountain multiple access, etc.

数字喷泉码是针对大规模网络数据分发和可靠传输而提出的一种新的纠删编码方法。与传统的纠删码不同，数字喷泉码可以按照某种概率分布独立地产生任意数量的码字，具有码率不受限或无码率(rateless)特性。接收者不必关心具体的编码分组及分组的顺序，只要接收到足够多的编码分组，就能实现正确的译码。目前研究喷泉码常用的码型为LT码和Raptor码。2002年Luby提出了第一种实用的数字喷泉码--LT码，并设计了实用的度分布(鲁棒孤波分布)，能够在任意删除信道中逼近信道容量，但其译码复杂度是非线性的。2006年Shokrollahi等人将高效的预编码与LT码级联，提出了性能更好的Raptor码，具有线性编译码复杂度。Digital fountain code is a new erasure coding method proposed for large-scale network data distribution and reliable transmission. Different from traditional erasure codes, digital fountain codes can independently generate any number of codewords according to a certain probability distribution, and have the characteristics of unlimited code rate or no code rate (rateless). The receiver does not need to care about the specific coded packets and the order of the packets, as long as enough coded packets are received, correct decoding can be achieved. At present, the code types commonly used in the study of fountain codes are LT codes and Raptor codes. In 2002, Luby proposed the first practical digital fountain code - LT code, and designed a practical degree distribution (robust solitary wave distribution), which can approach the channel capacity in any erasure channel, but its decoding complexity is very high. linear. In 2006, Shokrollahi et al. concatenated efficient precoding with LT codes, and proposed Raptor codes with better performance, which have linear encoding and decoding complexity.

LT(Luby Transform)码是第一种具有实用意义的数字喷泉码。这类码的主要参数是输出度分布，即对应不同度数{1,2,…,d_max}的不同概率值{1,2,…,d_max}。常用生成函数的形式来表达假设原始数据包长度为K，LT码的编码方案为：(1)在输出度分布Ω(x)中随机选取一个度数i；(2)再从K个原始数据包符号中均匀随机选取出i个不同的符号，将这i个符号进行异或得到一个编码符号；(3)重复上面的操作，即可完成LT编码。LT (Luby Transform) code is the first digital fountain code with practical significance. The main parameter of this type of code is the output degree distribution, that is, different probability values {1,2,...,d _{max } corresponding to different degrees {1,2,...,d max }} . Commonly expressed in the form of generating functions Assuming that the length of the original data packet is K, the encoding scheme of the LT code is: (1) randomly select a degree i from the output degree distribution Ω(x); (2) uniformly randomly select i from the K original data packet symbols different symbols, XOR the i symbols to obtain a coding symbol; (3) repeat the above operation to complete the LT coding.

Raptor码采用级联编码的形式，将高效的线性分组码作为外码，LT码作为内码。记线性分组码(n,k)为(n,k)，LT码的度分布为Ω(x)，则Raptor码可以记为(k,C,Ω(x))。线性分组码C称为Raptor码的预编码，一般采用高码率的汉明码或者LDPC码等。预编码将k个原始信息符号编码成长度为n的码字，作为中间编码符号，再进行LT编码。Raptor码的编码方案为：(1)预编码：对输入矢量x＝(x₁,x₂,…,x_k)进行线性分组码编码，得到长度为n的码字z＝(z₁,z₂,…,z_n)；(2)LT编码：将z＝(z₁,z₂,…,z_n)作为LT码的输入符号，采用度分布函数Ω(x)，按上述算法进行LT编码，得到输出编码符号y₁,y₂,…,y_j,…。The Raptor code adopts the form of concatenated coding, and the efficient linear block code is used as the outer code, and the LT code is used as the inner code. Denote the linear block code (n,k) as (n,k), and the degree distribution of the LT code as Ω(x), then the Raptor code can be denoted as (k,C,Ω(x)). The linear block code C is called the precoding of the Raptor code, and generally uses a high code rate Hamming code or LDPC code. Precoding encodes k original information symbols into codewords of length n, which are used as intermediate coded symbols, and then LT coded. The coding scheme of the Raptor code is: (1) Precoding: Carry out linear block code coding on the input vector x=(x ₁ ,x ₂ ,…,x _k ), and obtain a code word z=(z ₁ ,z ₂ ,…,z _n ); (2) LT coding: take z=(z ₁ ,z ₂ ,…,z _n ) as the input symbol of the LT code, adopt the degree distribution function Ω(x), and perform LT according to the above algorithm Encoding to obtain the output encoding symbols y ₁ , y ₂ ,…,y _j ,….

在无线信道中，由于噪声的干扰，需要采用可靠的软判决译码，常用的为BP译码。系统喷泉码常用的传输方式为增量传输，增量传输步骤为：a.开销为0时，发送端直接发送n个比特数据，若接收端能正确接收，则向发射端发送正确接收反馈信号，发射端结束或发送下一帧数据；若不能正确接收，接收端像发射端反馈接收失败信号；b.发射端接收到失败反馈信号后，发送一段长度为nΔε的编码增量作为校验信息，接收端在接收到这一段校验信息之后将增量与上一次接收到的数据合并成长度为n+nΔε编码信号，对这一接收信号计算似然比，并利用该似然比译码，若正确译码，则发送正确译码反馈信号，发射端结束或发送下一帧数据；若不能正确译码，则反馈接收失败信号；c.发射端端接收到失败反馈信号后继续如步骤二所述过程发送长度为nΔε的校验信息。以此类推，直到发送接收端正确译码为止，若此时发送次数为m，则总开销为mnΔε。即若发送数据长度为n个比特，每次编码增量开销为Δε，则每次编码增量长度为nΔε。当发送端发送m次编码增量后接收端正确译码，此时系统总开销为mnΔε，编码总长度为n(1+mΔε)。In wireless channels, due to the interference of noise, reliable soft-decision decoding is required, and BP decoding is commonly used. The commonly used transmission method of the system fountain code is incremental transmission, and the incremental transmission steps are: a. When the overhead is 0, the sending end directly sends n bits of data, and if the receiving end can receive it correctly, it sends a correct reception feedback signal to the sending end , the transmitting end ends or sends the next frame of data; if it cannot be received correctly, the receiving end will feed back the receiving failure signal like the transmitting end; b. After receiving the failure feedback signal, the transmitting end will send a code increment with a length of nΔε as the verification information , after receiving this piece of verification information, the receiving end combines the increment and the last received data into a coded signal with a length of n+nΔε, calculates the likelihood ratio for this received signal, and uses the likelihood ratio to decode , if it is correctly decoded, then send a correct decoding feedback signal, and the transmitter ends or sends the next frame of data; if it cannot be decoded correctly, it will feed back a reception failure signal; c. After the transmitter receives the failure feedback signal, continue as in the steps 2. The process sends check information with a length of nΔε. By analogy, until the sending and receiving end decodes correctly, if the number of times of sending is m at this time, the total overhead is mnΔε. That is, if the length of the transmitted data is n bits, and the overhead of each encoding increment is Δε, then the length of each encoding increment is nΔε. When the sender sends m code increments and the receiver decodes correctly, the total system overhead is mnΔε, and the total code length is n(1+mΔε).

发明内容Contents of the invention

本发明所要解决的技术问题是：提供一种喷泉多址接入方法，利用不同的喷泉码区分不同的用户，支持更多的用户传输数据，具有良好的系统误码率性能和吞吐率性能。The technical problem to be solved by the present invention is to provide a fountain multiple access method, which uses different fountain codes to distinguish different users, supports more users to transmit data, and has good system bit error rate performance and throughput performance.

本发明为解决上述技术问题采用以下技术方案：The present invention adopts the following technical solutions for solving the problems of the technologies described above:

一种喷泉多址接入方法，包括如下步骤：A fountain multiple access method, comprising the steps of:

步骤1，发送端对每个用户的发送数据采用喷泉码进行编码，获得编码序列；Step 1. The sending end encodes the data sent by each user with the fountain code to obtain the coding sequence;

步骤2，将每个用户的编码序列通过相同的交织器进行比特交织，对交织后的数据调制并发送出去；Step 2, performing bit interleaving on the coded sequence of each user through the same interleaver, modulating and sending the interleaved data;

步骤3，接收端接收多个用户叠加的数据信息，并对接收数据解调解交织；Step 3, the receiving end receives the data information superimposed by multiple users, and demodulates and interleaves the received data;

步骤4，在等概率设定下，根据接收数据计算每个用户的初始似然比，并将初始似然比送入BP译码器进行译码，得到各用户的输出似然比；Step 4, under the setting of equal probability, calculate the initial likelihood ratio of each user according to the received data, and send the initial likelihood ratio to the BP decoder for decoding to obtain the output likelihood ratio of each user;

步骤5，利用初始似然比和输出似然比计算每个用户的外信息，根据外信息估计每个用户发送数据的先验概率，将任意一个用户的先验概率送入剩余其他用户的BP译码器，得到剩余其他用户更新后的初始似然比；Step 5: Use the initial likelihood ratio and the output likelihood ratio to calculate the extrinsic information of each user, estimate the prior probability of each user's data transmission according to the extrinsic information, and send the prior probability of any user to the BP of the remaining other users The decoder obtains the updated initial likelihood ratios of other users;

步骤6，返回步骤4进行循环迭代，直至数据正确接收或达到预设的迭代次数；当达到预设的迭代次数且数据没有正确接收时，则向发送端发送反馈信号，重新进入步骤1。Step 6, return to step 4 for loop iterations until the data is received correctly or the preset number of iterations is reached; when the preset number of iterations is reached and the data is not received correctly, send a feedback signal to the sending end and re-enter step 1.

作为本发明的一种优选方案，步骤3所述多个用户叠加的数据信息表达式为：As a preferred solution of the present invention, the expression of the data information superimposed by multiple users described in step 3 is:

其中，y为接收端接收到的信号，h_i为第i个用户的信道冲击响应，p_i为第i个用户的信号发射功率，x_i为第i个用户的发送信号，i＝1,2,…,M，M为用户总数，n₀为高斯白噪声。Among them, y is the signal received by the receiving end, h _i is the channel impulse response of the i-th user, p _i is the signal transmission power of the i-th user, x _i is the transmission signal of the i-th user, i=1, 2,...,M, M is the total number of users, n ₀ is Gaussian white noise.

作为本发明的一种优选方案，步骤4所述初始似然比计算公式为：As a preferred solution of the present invention, the initial likelihood ratio calculation formula described in step 4 is:

其中，为第i个用户每个调制符号中第j个比特的初始似然比，p表示概率，为第i个用户接收符号中第j个比特信息，y为接收端接收到的信号，χ¹,χ²,…,χ^i-1,χⁱ⁺¹,…,χ^M表示除第i个用户外剩余其他每个用户所有星座点的集合，分别为第i个用户星座点中第j个比特为0、1的所有星座点的集合，h_i为第i个用户的信道冲击响应，p_i为第i个用户的信号发射功率，s_i为第i个用户的星座点信息，i＝1,2,…,M，M为用户总数，δ²为噪声功率。in, is the initial likelihood ratio of the j-th bit in each modulation symbol of the i-th user, p represents the probability, is the j-th bit information in the symbol received by the i-th user, y is the signal received by the receiving end, χ ¹ , χ ² ,...,χ ^i-1 , χ ⁱ⁺¹ ,..., χ ^M represent the i-th The set of all constellation points of each other user outside the user, are the set of all constellation points whose j-th bit is 0 and 1 in the i-th user constellation point respectively, h _i is the channel impulse response of the i-th user, p _i is the signal transmission power of the i-th user, s _i is the constellation point information of the i-th user, i=1,2,...,M, M is the total number of users, and δ ² is the noise power.

作为本发明的一种优选方案，步骤5所述先验概率的估计公式为：As a preferred solution of the present invention, the estimation formula of the prior probability described in step 5 is:

其中，p表示概率，x_i为第i个用户的发送信号， 为第i个用户每个调制符号中第j个比特的初始似然比，为第i个用户每个调制符号中第j个比特的输出似然比。Among them, p represents the probability, x _i is the transmission signal of the i-th user, is the initial likelihood ratio of the j-th bit in each modulation symbol of the i-th user, is the output likelihood ratio of the j-th bit in each modulation symbol of the i-th user.

作为本发明的一种优选方案，步骤5所述更新后的初始似然比计算公式为：As a preferred solution of the present invention, the updated initial likelihood ratio calculation formula described in step 5 is:

其中，为第i个用户每个调制符号中第j个比特更新后的初始似然比，p表示概率，为第i个用户接收符号中第j个比特信息，y为接收端接收到的信号，χ¹,χ²,…,χ^i-1,χⁱ⁺¹,…,χ^M表示除第i个用户外剩余其他每个用户所有星座点的集合，分别为第i个用户星座点中第j个比特为0、1的所有星座点的集合，h_i为第i个用户的信道冲击响应，p_i为第i个用户的信号发射功率，s_i为第i个用户的星座点信息，i＝1,2,…,M，M为用户总数，δ²为噪声功率，p(s_n)为第n个用户接收到星座点s_n的概率，s_n为第n个用户的星座点信息。in, is the updated initial likelihood ratio of the j-th bit in each modulation symbol of the i-th user, p represents the probability, is the j-th bit information in the symbol received by the i-th user, y is the signal received by the receiving end, χ ¹ , χ ² ,...,χ ^i-1 , χ ⁱ⁺¹ ,..., χ ^M represent the i-th The set of all constellation points of each other user outside the user, are the set of all constellation points whose j-th bit is 0 and 1 in the i-th user constellation point respectively, h _i is the channel impulse response of the i-th user, p _i is the signal transmission power of the i-th user, s _i is the constellation point information of the i-th user, i=1,2,...,M, M is the total number of users, δ ² is the noise power, p(s _n ) is the probability that the n-th user receives the constellation point s _n , s _n is the constellation point information of the nth user.

本发明采用以上技术方案与现有技术相比，具有以下技术效果：Compared with the prior art, the present invention adopts the above technical scheme and has the following technical effects:

1、本发明喷泉多址接入方法，通过不同的生成矩阵产生不同的喷泉码(相同的度分布函数)用以区分多用户，因为产生生成矩阵的种子数量有无数种，所以喷泉多址能同时区分大量的用户。1. The fountain multiple access method of the present invention generates different fountain codes (same degree distribution function) through different generation matrices to distinguish multiple users, because the number of seeds that generate the generation matrix has countless kinds, so the fountain multiple access can Differentiate a large number of users at the same time.

2、本发明喷泉多址接入方法，由于喷泉码的传输特点，不管多址干扰多严重，信道条件多恶劣，都可以增加开销(码长)完成正确译码，因此具有很强的自适应能力。2. The fountain multiple access method of the present invention, due to the transmission characteristics of the fountain code, no matter how serious the multiple access interference is and how bad the channel condition is, it can increase the overhead (code length) to complete the correct decoding, so it has strong self-adaptation ability.

3、本发明喷泉多址接入方法，喷泉多址接收信号时不需要用户间同步，不同的用户可以异步发送信号，但用户本身的同步仍然需要。3. In the fountain multiple access method of the present invention, the fountain does not require synchronization between users when multiple access signals are received, and different users can send signals asynchronously, but the synchronization of the users themselves is still required.

附图说明Description of drawings

图1是本发明喷泉多址接入方法的整体架构图。Fig. 1 is an overall architecture diagram of the fountain multiple access method of the present invention.

图2是本发明实施例两用户时吞吐率仿真图。Fig. 2 is a simulation diagram of throughput rate when there are two users according to the embodiment of the present invention.

图3是本发明实施例两用户时误码率仿真图。Fig. 3 is a simulation diagram of bit error rate when there are two users according to the embodiment of the present invention.

具体实施方式detailed description

下面详细描述本发明的实施方式，所述实施方式的示例在附图中示出。下面通过参考附图描述的实施方式是示例性的，仅用于解释本发明，而不能解释为对本发明的限制。Embodiments of the invention are described in detail below, examples of which are illustrated in the accompanying drawings. The embodiments described below by referring to the figures are exemplary only for explaining the present invention and should not be construed as limiting the present invention.

如图1所示，本发明喷泉多址接入方法，包括如下步骤：As shown in Figure 1, the fountain multiple access method of the present invention comprises the following steps:

步骤1，发送端对每个用户的发送数据采用喷泉码进行编码，获得编码序列；不同用户的喷泉码的度分布相同，产生喷泉码生成矩阵的种子不同，用不同的生成矩阵区分多用户。Step 1. The sending end encodes the data sent by each user with a fountain code to obtain a coding sequence; the degree distribution of the fountain codes of different users is the same, and the seeds for generating the fountain code generation matrix are different, and different generation matrices are used to distinguish multiple users.

步骤2，将每个用户的编码序列通过相同的交织器进行比特交织，对交织后的数据调制并发送出去；每个用户的交织器相同，即交织器的映射规则相同。In step 2, the coded sequence of each user is bit-interleaved through the same interleaver, and the interleaved data is modulated and sent out; the interleaver of each user is the same, that is, the mapping rule of the interleaver is the same.

步骤3，接收端接收多个用户叠加的数据信息，并对接收数据解调解交织。Step 3: The receiving end receives data information superimposed by multiple users, and demodulates and interleaves the received data.

步骤4，在等概率设定下，根据接收数据计算每个用户的初始似然比，并将初始似然比送入BP译码器进行译码，得到各用户的输出似然比。Step 4. Under the setting of equal probability, calculate the initial likelihood ratio of each user according to the received data, and send the initial likelihood ratio to the BP decoder for decoding to obtain the output likelihood ratio of each user.

步骤5，利用初始似然比和输出似然比计算每个用户的外信息，根据外信息估计每个用户发送数据的先验概率，将任意一个用户的先验概率送入剩余其他用户的BP译码器，得到剩余其他用户更新后的初始似然比。Step 5: Use the initial likelihood ratio and the output likelihood ratio to calculate the extrinsic information of each user, estimate the prior probability of each user's data transmission according to the extrinsic information, and send the prior probability of any user to the BP of the remaining other users The decoder obtains the updated initial likelihood ratios of the rest of the users.

在步骤4、5中，每个用户似然比更新基本公式为：In steps 4 and 5, the basic formula for updating the likelihood ratio of each user is:

上式中，p(s_n)表示第n个用户接收到星座点s_n的概率，p(x_t)为星座点s_n中第t个比特信息的先验概率，k为星座点中比特位数。当调制的阶数为m时，星座点中比特位数k＝2^m。In the above formula, p(s _n ) represents the probability that the nth user receives the constellation point s _n , p(x _t ) is the prior probability of the tth bit information in the constellation point s _n , and k is the number of bits in the constellation point. When the modulation order is m, the number of bits in the constellation point k=2 ^m .

计算第一次迭代的初始似然比时，接收端不知道任何先验信息，所以假设发射端发送0和1的概率是相等的，即计算似然比时，上式中相等。When calculating the initial likelihood ratio of the first iteration, the receiving end does not know any prior information, so it is assumed that the probability of sending 0 and 1 at the transmitting end is equal, that is, when calculating the likelihood ratio, the above formula equal.

步骤6，返回步骤4进行循环迭代，直至数据正确接收或达到预设的迭代次数；当达到预设的迭代次数且数据没有正确接收时，则向发送端发送反馈信号，重新进入步骤1。Step 6, return to step 4 for loop iterations until the data is received correctly or the preset number of iterations is reached; when the preset number of iterations is reached and the data is not received correctly, send a feedback signal to the sending end and re-enter step 1.

以两用户BPSK调制(比特0映射为1，比特1映射为-1)为例，两用户时接收信号可表示为：Taking two-user BPSK modulation (bit 0 is mapped to 1, bit 1 is mapped to -1) as an example, the received signal for two users can be expressed as:

y＝h₁p₁x₁+h₂p₂x₂+n₀ y=h ₁ p ₁ x ₁ +h ₂ p ₂ x ₂ +n ₀

其中，h₁是用户1的信道冲击响应，p₁是用户1的发射功率，x₁是用户1的发送信号，h₂为用户2的信道冲击响应，p₂是用户2的发射功率，x₂是用户2的发送信号，n₀是高斯白噪声。具体过程如下：where h ₁ is the channel impulse response of user 1, p ₁ is the transmit power of user 1, x ₁ is the transmitted signal of user 1, h ₂ is the channel impulse response of user 2, p ₂ is the transmit power of user 2, x ₂ is the transmitted signal of user 2, and n ₀ is Gaussian white noise. The specific process is as follows:

本文仿真采用系统LT码，码长为1000，度分布为d＝[1 2 3 4 5 8 14 30 33200]，Ω＝[0.006 0.492 0.0339 0.2403 0.006 0.095 0.049 0.018 0.0356 0.033]，d表示度数，Ω表示度数对应的概率。两用户发送端分别产生一串二进制源数据，用上述度分布对源数据编码获得编码序列，并将编码序列送入BPSK调制器调制。调制后的编码序列在各自的交织器中打乱顺序，两个交织器的映射规则是随机和独立的。The simulation in this paper adopts the system LT code, the code length is 1000, the degree distribution is d=[1 2 3 4 5 8 14 30 33200], Ω=[0.006 0.492 0.0339 0.2403 0.006 0.095 0.049 0.018 0.0356 0.033], d represents the degree, Ω represents Probability corresponding to degrees. The sending ends of the two users respectively generate a series of binary source data, use the above-mentioned degree distribution to encode the source data to obtain a coded sequence, and send the coded sequence to the BPSK modulator for modulation. The modulated code sequences are scrambled in their respective interleavers, and the mapping rules of the two interleavers are random and independent.

接收端对接收到的叠加信号计算初始似然比为：The receiving end calculates the initial likelihood ratio for the received superimposed signal as:

BP译码后得到两用户输出似然比分别为llr₁、llr₂，此时可以计算出外信息vllr₁、vllr₂，则先验概率为：After BP decoding, the output likelihood ratios of the two users are llr _{1 and llr 2 respectively. At this time, the extrinsic information vllr 1 and vllr 2 can be} calculated, and the prior probability is:

由此，可以获得更新后初始似然比为：Thus, the updated initial likelihood ratio can be obtained as:

将更新后的两用户的初始似然比送入译码器重新译码，直到译出或达到最大迭代次数。The updated initial likelihood ratios of the two users are sent to the decoder for re-decoding until it is decoded or reaches the maximum number of iterations.

归一化后两用户的功率为0.5和0.5，迭代次数为20次。如图2所示，可以看出本发明两用户时的吞吐率性能。如图3所示，可以看出本发明两用户时的误码率性能。After normalization, the powers of the two users are 0.5 and 0.5, and the number of iterations is 20. As shown in FIG. 2 , it can be seen that the throughput rate performance of the present invention when there are two users. As shown in FIG. 3 , it can be seen that the bit error rate performance of the present invention when there are two users.

以上实施例仅为说明本发明的技术思想，不能以此限定本发明的保护范围，凡是按照本发明提出的技术思想，在技术方案基础上所做的任何改动，均落入本发明保护范围之内。The above embodiments are only to illustrate the technical ideas of the present invention, and cannot limit the protection scope of the present invention with this. All technical ideas proposed according to the present invention, any changes made on the basis of technical solutions, all fall within the protection scope of the present invention. Inside.