CN102143102A - Preamble design-based cooperative diversity orthogonal frequency division multiplexing (OFDM) timing and frequency offset estimation method - Google Patents

Preamble design-based cooperative diversity orthogonal frequency division multiplexing (OFDM) timing and frequency offset estimation method Download PDF

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CN102143102A
CN102143102A CN 201110122846 CN201110122846A CN102143102A CN 102143102 A CN102143102 A CN 102143102A CN 201110122846 CN201110122846 CN 201110122846 CN 201110122846 A CN201110122846 A CN 201110122846A CN 102143102 A CN102143102 A CN 102143102A
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relay
destination
number
offset
frequency
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丁海洋
刘刚
葛建华
郭漪
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西安电子科技大学
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Abstract

The invention discloses a preamble design-based cooperative diversity orthogonal frequency division multiplexing (OFDM) timing and frequency offset estimation method in the field of wireless communication, which aims to mainly solve the problems of low accuracy, high complexity and low transmission efficiency of timing and frequency offset estimation from relays to a destination in a conventional cooperative diversity OFDM system. The method is implemented by the following steps of: (1) designing training sequences of each relay; (2) simultaneously transmitting the training sequences to the destination by using each relay; (3) estimating rough timing offset between the relays and the destination; (4) estimating fine timing offset between each relay and the destination; (5) calculating estimation values of the timing offset between each relay and the destination; (6) estimating decimal frequency offset between each relay and the destination; (7) estimating integral frequency offset between each relay and the destination; and (8) calculating the estimation values of the frequency offset between each relay and the destination. By the method, the timing and frequency offset estimation performance can be improved, the operational complexity can be reduced and the transmission efficiency can be improved.

Description

基于导频设计的协作分集OFDM定时和频率偏移估计方法 Offset estimation method based on the pilot design cooperative diversity OFDM timing and frequency

技术领域 FIELD

[0001] 本发明属于通信技术领域,涉及一种无线通信系统中的定时和频率偏移估计方法,尤其是一种协作分集OFDM系统中由中继到目的端的定时和频率偏移估计方法,用于目的端解调接收信号。 [0001] The present invention belongs to the field of communication technology, relates to a wireless communication timing and frequency offset estimation method in a system, in particular a cooperative diversity OFDM system estimation method by the relay destination to the timing and frequency offset, with demodulated received signal at the destination.

背景技术 Background technique

[0002] 在无线通信网络中,时间、频率和空间上的分集可以减小信道衰落对接收信号的影响.协作分集技术通过使网络中各单天线用户共享彼此天线,形成虚拟的多天线阵列来实现发射或接收分集,是一种虚拟多输入多输出MIMO技术,它最初是由Laneman和Womell 提出的.正交频分复用OFDM技术能够抵抗无线信道的频率选择性衰落,与MIMO相结合可以有效地提高传输速率和传输质量。 [0002] In a wireless communication network, the diversity in time, frequency and spatial effect of the channel fading of the received signal can be reduced. Cooperative diversity by allowing the network each single-antenna user antenna sharing with each other, forming a virtual multi-antenna array achieve transmit or receive diversity, is a virtual multiple input multiple output (MIMO) technology, which was originally proposed by Laneman and Womell. orthogonal frequency division multiplexing (OFDM) techniques capable of resisting frequency selective fading radio channel, MIMO can be combined with effectively increase the transmission rate and transmission quality. 因此,基于OFDM的协作分集技术有可能成为下一代无线通信网中重要的网络组成构架。 Accordingly, based on cooperative diversity OFDM may become important in a network of the next generation wireless communication network architecture. 然而,OFDM系统对定时偏移、频率偏移等同步误差非常敏感,非理想的同步会严重影响OFDM系统的性能,因此同步技术是协作分集OFDM系统中的关键技术之一。 However, OFDM systems are very sensitive to synchronization error timing offset, frequency offset, non-ideal synchronous OFDM system can seriously affect the performance, and therefore synchronization is a key technology cooperative diversity in an OFDM system.

[0003] 针对这一问题,有些研究者提出了采用抵抗时延的传输技术以避开定时偏移估计,虽然这些方法非常新颖,但是它对数据的传输以及用户之间的协作强加了很多条件, 从而限制了它的应用。 [0003] To solve this problem, some researchers have proposed transmission technology to avoid resistance to delay the timing offset estimation, although these methods are very innovative, but the cooperation between transmission of its data and users impose a number of conditions , thus limiting its application. 2008 年Andreas Ibing 在“5th IEEE International Symposium on Wireless Communication Systems”(第5 届IEEE 无线通信系统国际会议)(2008 ¥ )发^:白勺“MMSE channel estimation and time synchronization tracking for cooperative MIM0-0FDM with propagation delay differences"(《存在传输时延差环境下协作分集MIM0-0FDM系统中的匪SE信道估计及定时同步跟踪》)考虑了定时偏移估计,但没有涉及频率偏移估计问题;2009年Yusi Cheng等在“Proceedings of the2009 IEEE 70th Vehicular Technology Conference,,(第7O 届IEEE VTC 国际会议)(2OO9 年) 发^:白勺“Preamble design and synchronization algorithm for cooperative relay systems.”(《协作分集系统中的训练序列设计及同步算法研究》)同时考虑了定时和频率偏移估计,但是其定时和频率偏移估计精度不高,同时由于其训练序列长度接近三个OFDM 符号,传输效率较低,而且在定时偏移估计特别 In 2008 Andreas Ibing in the "5th IEEE International Symposium on Wireless Communication Systems" (5th IEEE International Conference on Wireless Communication System) (2008 ¥) ^ hair: white spoon "MMSE channel estimation and time synchronization tracking for cooperative MIM0-0FDM with propagation delay differences "(" SE bandit present cooperative diversity channel set MIM0-0FDM system estimation and timing synchronization tracking "lower transmission delay difference environment) considering timing offset estimation, but does not involve a frequency offset estimation; 2009 Yusi Cheng etc. in the "Proceedings of the2009 IEEE 70th Vehicular Technology Conference ,, (first 7O th IEEE VTC international Conference) (2OO9 years) made ^: white spoon". Preamble design and synchronization algorithm for cooperative relay systems "(" cooperative diversity system training and synchronization sequence design algorithm ") taking into consideration the timing and frequency offset estimation, but the timing and frequency offset estimation accuracy is not high, and because of its training sequence length closest three OFDM symbols, transmission efficiency is low, and in special timing offsets estimator 粗定时偏移估计中,各个中继都需要做不同间隔的滑动相关,复杂度较高。因此如何提高估计精度和传输效率、降低算法复杂度是协作分集OFDM系统同步研究中的重要问题。 The crude timing offset estimation, each repeater needs to do a sliding correlator different intervals, high complexity. Therefore, how to improve the estimation accuracy and transmission efficiency, reduce the complexity of the algorithm is an important problem Synchronization of OFDM systems cooperating set points.

发明内容 SUMMARY

[0004] 本发明的目的在于克服上述已有技术的缺点,提出一种基于导频设计的协作分集OFDM定时和频率偏移估计方法,以提高估计精度和传输效率,降低同步过程的复杂度。 [0004] The object of the present invention is to overcome the above disadvantages of the prior art, designed to provide a pilot-based cooperative diversity OFDM timing and frequency offset estimation method to improve the estimation accuracy and transmission efficiency, reduce the complexity of the synchronization process.

[0005] 为实现上述目的,本发明基于导频设计的协作分集OFDM定时偏移估计方法,包括以下步骤: [0005] To achieve the above object, the present invention is based on the pilot offset estimation method designed cooperative diversity OFDM timing comprising the steps of:

[0006] (1)设计第i个中继的时域训练序列Pi由两个相同的训练符号Ci构成,即Pi =[Ci Ci],Ci = [Ci,0, Cia, Λ,Ci,N_J对应的频域训练符号为 [0006] (1) designed to relay the i-th time domain training sequence Pi is composed of two identical training symbols Ci, i.e., Pi = [Ci Ci], Ci = [Ci, 0, Cia, Λ, Ci, N_J corresponding frequency domain training symbols

Figure CN102143102AD00061

[0008] 其中,N为正交频分复用OFDM子载波数,Zia, Zij2, A,ZijK是取值为+1或_1的伪随机序列,K为伪随机序列的长度,且K彡N/m, m为中继个数; [0008] where, N is the orthogonal frequency division multiplexing, OFDM, the number of subcarriers, Zia, Zij2, A, ZijK a value of +1 or pseudorandom sequence _1, K is the length of the pseudo-random sequence, and a K San N / m, m is the number of the relay;

[0009] (2)每个中继节点同时向目的端发送训练序列Pi,i = 1,2,. . . .,m ; [0009] (2) simultaneously transmitting each relay node to the destination end of the training sequence Pi, i = 1,2 ,., m...;

Figure CN102143102AD00062

[όσιο] (3)目的端对接收信号巾^Σ^^'^ΣΑω·尸办H')+"⑷中长度为 [Όσιο] (3) the destination of the received signal towel ^ Σ ^^ '^ ΣΑω · Office dead H') + "length of ⑷

Figure CN102143102AD00063

Ν/2-1、间隔为3N/2的两个数据块进行移动共轭对称相关,以计算中继和目的端之间的粗定时偏移之: Ν / 2-1, to move two spacing blocks 3N / 2 conjugate symmetry correlation between the relay and the destination to calculate a coarse timing offset of end:

Figure CN102143102AD00064

[0012] 其中,q为移动共轭相关起始位置,U为从q算起的数据序号,i为中继序号,Li为中继i和目的端之间信道响应的路径总数,1为路径序号,hi(l)为第1条路径的复增益,< 为第1条路径用采样周期归一化的路径时延,fi为中继i和目的端之间用子载波间隔归一化的频率偏移,Si为中继i和目的端之间用采样周期归一化的定时偏移,n (S)是均值为0,方差为N0的加性高斯白噪声,e = 2. 71828182……为自然常数,j为虚数单位,j2 = _1, π = 3. 1415926……为圆周率,s = 1,2,……表示接收信号的序号; [0012] where, q is related to the starting position of the mobile conjugate, U q counting from the data number, the serial number i of the relay, Li is the total number of paths i and a channel between the relay destination of the response, the path 1 number, hi (l) is the complex gain of the 1st path, <Article 1 by sampling cycle path normalized skew, i Fi between the relay and the destination sub-carrier spacing normalized frequency offset, Si of a normalized timing offset between the relay and the destination by i sampling periods, n (S) is zero mean and variance N0 is the additive white Gaussian noise, e = 2. 71828182 ... ... is a natural constant, j is the imaginary unit, j2 = _1, π = 3. 1415926 ...... is pi, s = 1,2, ...... represents a sequence number of the received signal;

[0013] (4)目的端进一步对接收信号r(s)与训练符号Ci进行分段移动相关,计算各中继与目的端之间的细定时偏移良/ : [0013] (4) further destination of the received signal r (s) and segmented training symbols Ci moved correlation calculation between the fine and the relay destination good timing offset /:

Figure CN102143102AD00065

[0015] 其中,H为分段数,V为每段数据点数,且H · V < N,n为段号,ν为段内数据序号, d为分段移动相关起始位置偏移量,Ω为分段移动相关的移动范围; [0015] where, H is the number of segments, V data points for each segment and the H · V <N, n is the segment number, the data segment number v, d is related to a movement start position of the segment offset, Ω is related to a movement of the segment moving range;

[0016] (5)将各中继与目的端之间的细定时偏移和粗定时偏移之相加得到各中继与目的端之间的定时偏移估计A =Sc+S1J ^ i = 1,2,. . .,m。 Adding [0016] (5) between the fine and the relay destination timing offset and the timing offset to obtain crude timing offset between the relay and the destination estimated A = Sc + S1J ^ i = 1,2 ,..., m.

[0017] 为实现上述目的,本发明基于导频设计的协作分集OFDM频率偏移估计方法,包括以下步骤: [0017] To achieve the above object, the present invention is based on the pilot offset estimation method designed cooperative diversity OFDM frequency, comprising the steps of:

[0018] 1)设计第i个中继的时域训练序列Pi由两个相同的训练符号Ci构成,即Pi = [Ci CiJjCi = [Ci,0, Cia, Λ,Ci,N_J对应的频域训练符号为 [0018] 1) Design of the i-th time domain training sequence relay Pi is composed of two identical training symbols Ci, i.e., Pi = [Ci CiJjCi = [Ci, 0, Cia, Λ, Ci, N_J corresponding frequency domain training symbol

Figure CN102143102AD00066

[0020] 其中,N为正交频分复用OFDM子载波数,Zia, Zij2, A,ZijK是取值为+1或_1的伪随机序列,K为伪随机序列的长度,且K彡N/m, m为中继个数; [0020] where, N is the orthogonal frequency division multiplexing, OFDM, the number of subcarriers, Zia, Zij2, A, ZijK a value of +1 or pseudorandom sequence _1, K is the length of the pseudo-random sequence, and a K San N / m, m is the number of the relay;

[0021] 2)每个中继节点同时向目的端发送训练序列Pi,i = 1,2,. . . .,m ; [0021] 2) each relay node to the destination simultaneously transmit the training sequence Pi, i = 1,2 ,., m...;

[0022] 3)目的端对接收信号r⑷= 1^^^1^)^0-6-0 + "⑷中长度为N/2-1、间隔为3N/2的两个数据块进行移动共轭对称相关,以计算中继和目的端之间的粗定时偏移之: [0022] 3) the destination of the received signal r⑷ = 1 ^^^ 1 ^) ^ 0-6-0 + "⑷ of length N / 2-1, at intervals of two blocks 3N / 2 is moved co symmetry-related yoke, between the relay and the destination to calculate a coarse timing offset of end:

[0024] 其中,q为移动共轭相关起始位置,U为从q算起的数据序号,i为中继序号,Li为中继i和目的端之间信道响应的路径总数,1为路径序号,hi(l)为第1条路径的复增益,< 为第1条路径用采样周期归一化的路径时延,fi为中继i和目的端之间用子载波间隔归一化的频率偏移,Si为中继i和目的端之间用采样周期归一化的定时偏移,n (S)是均值为0,方差为N0的加性高斯白噪声,e = 2. 71828182……为自然常数,j为虚数单位,j2 = _1, π = 3. 1415926……为圆周率,s = 1,2,……表示接收信号的序号; [0024] where, q is related to the starting position of the mobile conjugate, U q counting from the data number, the serial number i of the relay, Li is the total number of paths i and a channel between the relay destination of the response, the path 1 number, hi (l) is the complex gain of the 1st path, <Article 1 by sampling cycle path normalized skew, i Fi between the relay and the destination sub-carrier spacing normalized frequency offset, Si of a normalized timing offset between the relay and the destination by i sampling periods, n (S) is zero mean and variance N0 is the additive white Gaussian noise, e = 2. 71828182 ... ... is a natural constant, j is the imaginary unit, j2 = _1, π = 3. 1415926 ...... is pi, s = 1,2, ...... represents a sequence number of the received signal;

[0025] 4)目的端进一步对接收信号r(s)与训练符号Ci进行分段移动相关,计算各中继与目的端之间的细定时偏移: [0025] 4) further destination received signal r (s) associated with the mobile segmented training symbols Ci, fine calculation between the relay and the destination end timing offset:

[0027] 其中,H为分段数,V为每段数据点数,且H · V < N,n为段号,ν为段内数据序号, d为分段移动相关起始位置偏移量,Ω为分段移动相关的移动范围; [0027] where, H is the number of segments, V data points for each segment and the H · V <N, n is the segment number, the data segment number v, d is related to a movement start position of the segment offset, Ω is related to a movement of the segment moving range;

[0028] 5)将各中继与目的端之间的细定时偏移总,/和粗定时偏移之相加得到各中继与目的端之间的定时偏移估计A =Sc+Slf, i = 1,2,... ,m; [0028] 5) Total fine timing offset between the relay and the destination, and / adding coarse timing offset of each repeater obtained A = Sc + Slf estimate timing offset between the destination end, i = 1,2, ..., m;

[0029] 6)在步骤5)的基础上,目的端利用接收信号在频域对应子载波上的相位差,计算各中继与目的端之间的小数倍频率偏移又,; [0029] 6) on the basis of the step 5), based on the destination using the received signal phase difference in the frequency domain corresponding to subcarriers, calculate the relay and the small multiple of the frequency offset between the destination and,;

[0030] 7)目的端对接收信号r (s)在频域分别与&,i = 1,2,. . .,m进行分段相关,计算各中继与目的端之间的整数倍频率偏移}、c ; [0030] 7) the destination of the received signal r (s) in the frequency domain, respectively &, i = 1,2 ,..., M segmented correlation, calculating an integer multiple of the frequency between the relay and the destination end offset}, c;

[0031] 8)将各中继与目的端之间的小数倍频率偏移和整数倍频率偏移义,相加得到各 [0031] 8) a small multiple of the frequency between the relay and the destination offset and integer frequency offset sense, obtained by adding each of the

中继与目的端之间的频率偏移估计-.1 =又ε +又,,i = 1,2,. . .,m。 A frequency offset between the relay and the destination and the estimated -.1 = ε + and ,, i = 1,2 ,..., M.

[0032] 本发明具有如下优点: [0032] The present invention has the following advantages:

[0033] 1.由于本发明中各中继训练序列只需要两个OFDM符号,因而提高了系统传输效率; [0033] 1. Since the present invention, the relay training sequence requires only two OFDM symbols, thus increasing the transmission efficiency of the system;

[0034] 2.由于本发明中目的端只需要一个粗定时偏移估计器,因而降低了估计复杂度; [0034] 2. Since the object of the present invention requires only a rough end timing offsets estimator, thus reducing the complexity of the estimation;

[0035] 3.由于本发明中训练序列具有时域共轭对称性,且在目的端采用长度为N/2-1、 间隔为3N/2的两个数据块共轭对称相关,完成粗定时偏移估计,因而使得粗定时偏移估计函数曲线具有类似理想冲激函数的形状,估计精度更高; [0035] 3. Since the present invention has a time domain training sequence conjugate symmetry, and the use of length N / 2-1 at the destination, the interval of two data blocks 3N / 2 conjugate symmetry-related, the timing of completion of the crude offset estimation, so that the coarse timing offset estimation function curve having a shape similar to the desired impulse functions, higher precision estimation;

[0036] 4.由于本发明通过分段移动相关进行细定时偏移估计,因而进一步提高了定时偏移估计精度,从而具有更好的定时偏移估计性能; [0036] 4. As the present invention is finely moved by the segment relative timing offset estimation, which further enhances the accuracy of timing offset estimation, timing offset so as to have a better estimation performance;

[0037] 5.由于本发明设计的训练序列良好的时频域特性,因而能够同时估计出各中继与目的端之间的定时和频率偏移,并且估计性能良好。 [0037] 5. Since when the training sequence of the present invention, good design characteristics of the frequency domain, it is possible to simultaneously estimate the timing and frequency offsets between the relay and the destination, and the estimated good performance.

[0026] =argmax^^r(£c+J + («-l)-// + v)-c*(„_1>ff+ Id e Ω附图说明 [0026] = argmax ^^ r (£ c + J + ( «-l) - // + v) -c * (" _ 1> ff + Id e Ω BRIEF DESCRIPTION

[0038] 图1是现有协作分集的系统模型; [0038] FIG. 1 is a system model of the conventional cooperative diversity;

[0039] 图2是本发明基于导频设计的协作分集OFDM定时偏移估计流程图; [0039] The present invention is based on FIG. 2 is a cooperative diversity OFDM pilot design timing offset estimation flowchart;

[0040] 图3是本发明基于导频设计的协作分集OFDM频率偏移估计流程图; [0040] FIG. 3 is a collaboration of the present invention is based on pilot design diversity flowchart OFDM frequency offset estimation;

[0041] 图4是本发明设计的各中继训练序列频域结构示意图; [0041] FIG. 4 is a schematic view of the domain structure of the relay of the present invention, the training sequence design frequency;

[0042] 图5是图4中第i个中继训练符号Zi的时域结构示意图; [0042] FIG. 5 is a schematic diagram of a time domain structure of FIG. 4 i-th training symbols Zi of the relay;

[0043] 图6是本发明基于导频设计的协作分集OFDM频率偏移估计仿真结果图。 [0043] FIG. 6 is a simulation result of the present invention, FIG offset estimation based on pilot design cooperative diversity OFDM frequency.

具体实施方式 detailed description

[0044] 下面参照附图对本发明作进一步描述。 [0044] Referring to the drawings the present invention will be further described.

[0045] 图1为协作分集OFDM系统模型,协作过程分为两个阶段:第一阶段是源节点S向中继Rl,. . .,Rm广播信息;第二阶段是中继Rl,. . .,Rm向目的端D发送信号。 [0045] FIG. 1 is a cooperative diversity OFDM system model, a collaborative process divided into two stages: The first stage is the source node S to the relay Rl ,., Rm broadcast information; second stage is a relay Rl ,.... ., Rm sends a signal to the destination D. 相对应,把协作分集的定时和频率偏移估计分为两部分:一部分是源S和中继Rl,. . .,Rm之间的定时和频率偏移估计,另一部分是中继R1,...,Rm和目的端D之间的定时和频率偏移估计。 Correspondingly, the timing and frequency offset estimation cooperative diversity is divided into two parts: a part of the source S and the relay Rl ,., timing and frequency offset estimation between Rm and the other part is a relay R1 ,. .., timing and frequency Rm between the offset estimation and the destination D. 本发明适用于由中继Rl,. . .,Rm到目的端D的定时和频率偏移估计。 The present invention is applicable to the relay Rl ,..., Rm to the destination D timing and frequency offset estimation.

[0046] 参照图2,本发明基于导频设计的协作分集OFDM由中继Rl,. . .,Rm到目的端D的定时偏移估计步骤如下: . [0046] Referring to Figure 2, a timing offset estimation step is based on the design of pilot OFDM cooperative diversity by the relay Rl ,., Rm destination D to the invention is as follows:

[0047] 步骤1 :设计各中继训练序列。 [0047] Step 1: Design of the relay training sequence.

[0048] 设计第i个中继的时域训练序列Pi由两个相同的训练符号Ci构成,即Pi = [Ci CiJjCi = [Ci,0, Cia, Λ,Ci,N_J对应的频域训练符号为: [0048] Design of the i-th time domain training sequence relay Pi is composed of two identical training symbols Ci, i.e., Pi = [Ci CiJjCi = [Ci, 0, Cia, Λ, Ci, N_J corresponding frequency domain training symbols for:

[0049] Z,=[9,h0,Zu,及2,八,^^,企30]i = 1,2,....,m [0049] Z, = [9, h0, Zu, and 2, eight, ^^, half 30] i = 1,2, ...., m

(ζ-1)·Κ NiK (Ζ-1) · Κ NiK

[0050] 如图4所示,其中,N为正交频分复用OFDM子载波数,Zia, Zi,2, Λ,是取值为+1或-1的伪随机序列,K为伪随机序列的长度,且K < N/m, m为中继个数。 [0050] 4, wherein, N is the number of orthogonal frequency-division multiplexing subcarriers OFDM, Zia, Zi, 2, Λ, is the value of pseudo-random sequence of +1 or -1, K pseudorandom length of the sequence, and K <N / m, m is the number of the relay.

[0051] 由于k取值为实数,根据离散付里叶逆变换IFFT的性质易知 [0051] Since the value of k is a real number, in accordance with an inverse discrete Fourier transform is easy to know the nature of the IFFT

[0052] [0052]

Figure CN102143102AD00081

[0053] 即时域训练符号Ci具有共轭对称性,其结构如图5所示,图5中Ai部分的数据与Bi部分的数据具有共轭对称的性质。 [0053] Ci having time domain training symbols conjugate symmetry, the structure shown in Figure 5, the data Ai and Bi portion of the portion of FIG. 5 having the conjugate symmetry properties.

[0054] 步骤2 :每个中继节点同时向目的端发送训练序列Pi,i = 1,2,. . . . m。 [0054] Step 2: Each relay node sends to the destination while the training sequence Pi, i = 1,2 ,. m....

[0055] 步骤3 :估计中继与目的端之间的粗定时偏移。 [0055] Step 3: The crude estimate timing offset between the relay and the destination.

[0056] 目的端利用训练序列Pi,i = 1,2, ....m的时域共轭对称性,对接收信号 [0056] destination training sequence Pi, i = 1,2, .... m of the time domain conjugate symmetry, the received signal

Figure CN102143102AD00082

进行移动共轭对称相关,以估计中继和目的端 Conjugate symmetry-related move, to estimate the relay and the destination end

之间的粗定时偏移。 Coarse timing offset between. 式中,S = l,2,……表示接收信号的序号,m为中继个数,i为中继序号,e = 2. 71828182……为自然常数,j为虚数单位,j2 = -1,ji = 3. 1415926……为圆周率,&为中继i和目的端之间用子载波间隔归一化的频率偏移,N为正交频分复用OFDM子载波数山为中继i和目的端之间信道响应的路径总数,1为路径序号,Iii⑴为第1条路径的复增益,<为用采样周期归一化的路径时延,ε i为中继i和目的端之间用采样周期归一化的定时偏移,Π (s)是均值为0,方差为Ntl的加性高斯白噪声。 In the formula, S = l, 2, ...... represents a sequence number of the received signal, m is the number of repeaters, i is the relay number, e = 2. 71828182 ...... is a natural constant, j is the imaginary unit, j2 = -1 , ji = 3. 1415926 ...... is pi, & i between the relay and the destination normalized frequency offset of subcarrier spacing, N is the orthogonal frequency-division multiplexing OFDM subcarriers relay mountain i and the total number of paths between the destination of the channel response, the path number 1, Iii⑴ is a complex gain of the 1st path, <path is normalized by the sampling period delay, i [epsilon] i between the relay and the destination end normalized timing offset of the sampling period, Π (s) is the mean of 0 and variance of additive white gaussian noise of Ntl.

[0057] 3a)定义中继和目的端之间的粗定时偏移估计函数 Coarse timing offset between [0057] 3a) defines the relay and the destination estimation function

[0058] 由于本发明设计的各中继训练序列前后两个训练符号完全相同且均具有共轭对称性,为了保证粗定时偏移估计函数的单峰性,本发明选择长度为N/2-1、间隔为3N/2的两个数据块进行共轭相关,因此中继和目的端之间的粗定时偏移估计函数定义为: [0058] Since the relay before and after the training sequence of the present invention, two training symbols identical design and both have a conjugate symmetry, in order to ensure that coarse unimodal function of the timing offset estimation, the present invention is to select the length of N / 2- 1, a data interval of two blocks 3N / 2 conjugated related, thus defining a coarse timing offset estimation function between the relay and the destination of:

Λί/2-l 2 Λί / 2-l 2

^r(q + u)-r(q + 2N-u) ^ R (q + u) -r (q + 2N-u)

[0059] r(q) = ^--^—— [0059] r (q) = ^ - ^ -

^N/2-1 V ^ N / 2-1 V

Σ I咖+Μ)|2 Σ I coffee + Μ) | 2

V u=\ J V u = \ J

[0060] 其中,q为移动共轭相关起始位置,U为从q算起的信号序号,r (q+u)为接收到的第q+u个信号,r (q+2N-u)为接收到的第q+2N_u个信号。 [0060] where, q is related to the starting position of the mobile conjugate, U q is the sequence number from counting signal, r (q + u) of the received signal q + u, r (q + 2N-u) for the received signals of q + 2N_u.

[0061] 3b)估计中继和目的端之间的粗定时偏移 [0061] 3b) the crude estimate timing offset between the relay and the destination end

[0062] 当粗定时偏移估计函数Γ (q)取到最大值时所对应的q,即为中继和目的端之间的粗定时偏移估计,因此中继和目的端之间的粗定时偏移估计为: [0062] When the coarse timing offset estimation function Γ (q) takes a maximum value corresponding to q, that is, the coarse timing offset between the relay and the destination is estimated, so the crude between the relay and the destination timing offsets estimator is:

[0063]之= argmax(r ⑷)。 [0063] The = argmax (r ⑷).

[0064] 步骤4 :估计各中继与目的端之间的细定时偏移。 [0064] Step 4: fine estimation between the relay and the destination timing offset.

[0065] 4a)定义各中继和目的端之间的细定时偏移估计函数 Fine between the relay and the destination [0065] 4a) defined timing offset estimation function

[0066] 由于频率偏移引起的接收信号的相位旋转会严重影响细定时偏移估计性能,为了消除这一影响,采用分段相关来完成细定时偏移估计,定义第i个中继与目的端之间的细定时偏移估计函数为: [0066] Since the phase rotation of the received signal is seriously affected due to frequency offset fine timing offset estimation performance, in order to eliminate this effect, related to the segment using the fine timing offset estimation is completed, the definition of the i-th relay and the object fine timing offset between the ends of the estimation function is:

HV HV

[0067] Φ,(ά) = TjTj^sc+d + (nl)·H+ V)·c*(n_l>H+vde Ω [0067] Φ, (ά) = TjTj ^ sc + d + (nl) · H + V) · c * (n_l> H + vde Ω

η=\ ν=1 η = \ ν = 1

[0068] 其中,H为分段数,V为每段数据点数,且H · V < N,n为段号,ν为段内数据序号, d为分段移动相关起始位置偏移量,Ω为分段移动相关的移动范围。 [0068] where, H is the number of segments, V data points for each segment and the H · V <N, n is the segment number, the data segment number v, d is related to a movement start position of the segment offset, Ω is related to a movement of the moving range segment.

[0069] 4b)估计各中继和目的端之间的细定时偏移 [0069] 4b) between the estimated fine and destination relay timing offset

[0070] 当细定时偏移估计函数Oi(Cl)取到最大值时所对应的d,即为第i个中继和目的端之间的细定时偏移估计,因此第i个中继和目的端之间的细定时偏移估计为: [0070] When the fine timing offset estimation function Oi (Cl) corresponding to the maximum to get d, is the i-th fine timing offset estimation between the relay and the destination, and thus the i-th relay fine timing offset between the destination estimated as:

[0071] Kf = ar§ max(φ; (d))。 [0071] Kf = ar§ max (φ; (d)).

[0072] 步骤5 :计算各中继与目的端之间的定时偏移估计值。 [0072] Step 5: calculation of timing offset estimation value between the relay and the destination.

[0073] 将各中继与目的端之间的细定时偏移总,/和粗定时偏移之相加,得到各中继与目的端之间的定时偏移估计A =Kf, i = 1,2,. . .,m。 [0073] The total fine timing offset between the relay and the destination, / and addition of coarse timing offset, the timing offset between the relay and the destination estimated A = Kf, i = 1 , 2 ,..., m.

[0074] 参照图3,本发明基于导频设计的协作分集OFDM由中继Rl,. . .,Rm到目的端D的频率偏移估计方法的具体步骤如下: . [0074] Step particular reference to FIG. 3, the present invention is based on cooperative diversity OFDM pilot design by the relay Rl ,., Rm destination D to the frequency offset estimation method is as follows:

[0075] 步骤1 :设计各中继训练序列。 [0075] Step 1: Design of the relay training sequence.

[0076] 设计第i个中继的时域训练序列Pi由两个相同的训练符号Ci构成,即Pi = [Ci CiJjCi = [Ci,0, Cia, Λ,Ci,N_J对应的频域训练符号为: [0076] Design of the i-th time domain training sequence relay Pi is composed of two identical training symbols Ci, i.e., Pi = [Ci CiJjCi = [Ci, 0, Cia, Λ, Ci, N_J corresponding frequency domain training symbols for:

[0077] Z,=[9,h0,Zu 名'2,八,^^,企30]i = 1,2,. .,m [0077] Z, = [9, h0, Zu name '2, eight, ^^, half 30] i = 1,2 ,.., M

(ζ-1)·Κ NiK[0078] 如图4所示,其中,N为正交频分复用OFDM子载波数,Zia, Zi,2, Λ,是取值为+1或-1的伪随机序列,K为伪随机序列的长度,且K < N/m, m为中继个数。 (Ζ-1) · Κ NiK [0078] 4, wherein, N is the number of orthogonal frequency-division multiplexing subcarriers OFDM, Zia, Zi, 2, Λ, a value of +1 or -1 pseudo-random sequence, K is the length of the pseudo-random sequence, and K <N / m, m is the number of the relay.

[0079] 由于k取值为实数,根据离散付里叶逆变换IFFT的性质易知 [0079] Since the value of k is a real number, in accordance with an inverse discrete Fourier transform is easy to know the nature of the IFFT

[0080] cix=c*N_xx = I, Λ, Ν/2 [0080] cix = c * N_xx = I, Λ, Ν / 2

[0081] 即时域训练符号Ci具有共轭对称性,其结构如图5所示,图5中Ai部分的数据与Bi部分的数据具有共轭对称的性质。 [0081] Ci having time domain training symbols conjugate symmetry, the structure shown in Figure 5, the data Ai and Bi portion of the portion of FIG. 5 having the conjugate symmetry properties.

[0082] 步骤2 :每个中继节点同时向目的端发送训练序列Pi,i = 1,2,. . . . m。 [0082] Step 2: Each relay node sends to the destination while the training sequence Pi, i = 1,2 ,. m....

[0083] 步骤3 :估计中继与目的端之间的粗定时偏移。 [0083] Step 3: The crude estimate timing offset between the relay and the destination.

[0084] 目的端利用训练序列Pi,i = 1,2, ....m的时域共轭对称性,对接收信号 [0084] The object of the training sequence end Pi, i = 1,2, .... m of the time domain conjugate symmetry, the received signal

Φ)=· ΣΑω·/^-呙-⑷进行移动共轭对称相关,以估计中继和目的端 Φ) = · ΣΑω · / ^ - Guo -⑷ conjugate symmetry-related move, to estimate the relay and the destination end

之间的粗定时偏移。 Coarse timing offset between. 式中,s = l,2,……表示接收信号的序号,m为中继个数,i为中继序号,e = 2. 71828182……为自然常数,j为虚数单位,j2 = -1,ji = 3. 1415926……为圆周率,&为中继i和目的端之间用子载波间隔归一化的频率偏移,N为正交频分复用OFDM子载波数山为中继i和目的端之间信道响应的路径总数,1为路径序号,Iii⑴为第1条路径的复增益,<为用采样周期归一化的路径时延,ε i为中继i和目的端之间用采样周期归一化的定时偏移,n (s)是均值为0,方差为Ntl的加性高斯白噪声。 Where, s = l, 2, ...... represents a sequence number of the received signal, m is the number of repeaters, i is the relay number, e = 2. 71828182 ...... is a natural constant, j is the imaginary unit, j2 = -1 , ji = 3. 1415926 ...... is pi, & i between the relay and the destination normalized frequency offset of subcarrier spacing, N is the orthogonal frequency-division multiplexing OFDM subcarriers relay mountain i and the total number of paths between the destination of the channel response, the path number 1, Iii⑴ is a complex gain of the 1st path, <path is normalized by the sampling period delay, i [epsilon] i between the relay and the destination end normalized timing offset of the sampling period, n (s) is the mean of 0 and variance of additive white gaussian noise of Ntl.

[0085] 3a)定义中继和目的端之间的粗定时偏移估计函数 Coarse timing offset between [0085] 3a) defines the relay and the destination estimation function

[0086] 由于本发明设计的各中继训练序列前后两个训练符号完全相同且均具有共轭对称性,为了保证粗定时偏移估计函数的单峰性,本发明选择长度为N/2-1、间隔为3N/2的两个数据块进行共轭相关,因此中继和目的端之间的粗定时偏移估计函数定义为: [0086] Since the relay before and after the training sequence of the present invention, two training symbols identical design and both have a conjugate symmetry, in order to ensure that coarse unimodal function of the timing offset estimation, the present invention is to select the length of N / 2- 1, a data interval of two blocks 3N / 2 conjugated related, thus defining a coarse timing offset estimation function between the relay and the destination of:

[0088] 其中,q为移动共轭相关起始位置,U为从q算起的信号序号,r (q+u)为接收到的第q+u个信号,r (q+2N-u)为接收到的第q+2N_u个信号。 [0088] where, q is related to the starting position of the mobile conjugate, U q is the sequence number from counting signal, r (q + u) of the received signal q + u, r (q + 2N-u) for the received signals of q + 2N_u.

[0089] 3b)估计中继和目的端之间的粗定时偏移 [0089] 3b) the crude estimate timing offset between the relay and the destination end

[0090] 当粗定时偏移估计函数Γ (q)取到最大值时所对应的q,即为中继和目的端之间的粗定时偏移估计,因此中继和目的端之间的粗定时偏移估计为: [0090] When the coarse timing offset estimation function Γ (q) takes a maximum value corresponding to q, that is, the coarse timing offset between the relay and the destination is estimated, so the crude between the relay and the destination timing offsets estimator is:

[0091]之= argmax(r&))。 [0091] The = argmax (r &)).

[0092] 步骤4 :估计各中继与目的端之间的细定时偏移。 [0092] Step 4: fine estimation between the relay and the destination timing offset.

[0093] 4a)定义各中继和目的端之间的细定时偏移估计函数 Fine between the relay and the destination [0093] 4a) defined timing offset estimation function

[0094] 由于频率偏移引起的接收信号的相位旋转会严重影响细定时偏移估计性能,为了消除这一影响,采用分段相关来完成细定时偏移估计,定义第i个中继与目的端之间的细定时偏移估计函数为: [0094] Since the phase rotation of the received signal is seriously affected due to frequency offset fine timing offset estimation performance, in order to eliminate this effect, related to the segment using the fine timing offset estimation is completed, the definition of the i-th relay and the object fine timing offset between the ends of the estimation function is:

[0087] Γ(妁= [0087] Γ (matchmaker =

[0095] Φ, = Σ Σ r + ^ + - ! [0095] Φ, = Σ Σ r + ^ + -! ) ' ^ + ν) ' cIin-VyH+vde Ω[0096] 其中,H为分段数,V为每段数据点数,且H · V < N,η为段号,ν为段内数据序号, d为分段移动相关起始位置偏移量,Ω为分段移动相关的移动范围。 ) '^ + Ν)' cIin-VyH + vde Ω [0096] where, H is the number of segments, V data points for each segment and the H · V <N, η is the segment number, the data segment number v, d is related to a movement start position of the segment offset, Ω motion range segments related to a movement.

[0097] 4b)估计各中继和目的端之间的细定时偏移 [0097] 4b) between the estimated fine and destination relay timing offset

[0098] 当细定时偏移估计函数Oi(Cl)取到最大值时所对应的d,即为第i个中继和目的端之间的细定时偏移估计,因此第i个中继和目的端之间的细定时偏移估计为: [0098] When the fine timing offset estimation function Oi (Cl) corresponding to the maximum to get d, is the i-th fine timing offset estimation between the relay and the destination, and thus the i-th relay fine timing offset between the destination estimated as:

[0099] [0099]

Figure CN102143102AD00111

[0100] 步骤5 :计算各中继与目的端之间的定时偏移估计值。 [0100] Step 5: calculation of timing offset estimation value between the relay and the destination.

[0101] 将各中继与目的端之间的细定时偏移总,/和粗定时偏移之相加,得到各中继与目的端之间的定时偏移估计A =Kf, i = 1,2,. . .,m。 [0101] The total fine timing offset between the relay and the destination, / and addition of coarse timing offset, the timing offset between the relay and the destination estimated A = Kf, i = 1 , 2 ,..., m.

[0102] 步骤6 :估计各中继与目的端之间的小数倍频率偏移。 [0102] Step 6: estimating a small multiple of the frequency between the relay and the destination offset.

[0103] 目的端利用接收信号在频域对应子载波上的相位差,估计各中继与目的端之间的小数倍频率偏移又,: [0103] the destination using the received signal phase difference in the frequency domain corresponding to subcarriers, a small multiple of the frequency estimates between the relay and the destination offset and,:

[0104] [0104]

[0105] 其中©(i)为第i个中继训练符号的频域子载波集合,a为子载波序号,Z (·)为求角度函数,R1(B)为接收到的第一个训练符号在第a个子载波上的数据,R2 (a)为接收到的第二个训练符号在第a个子载波上的数据。 [0105] © frequency domain wherein (i) is the i th training symbol relay set of subcarriers, a is the subcarrier index, Z (·) is a function of the angle demand, R1 (B) of the received first training a symbol data on the first subcarrier, R2 (a) data received at the second training symbol of a subcarrier.

[0106] 由于Z ( ·)以2 π为周期,因此小数倍频率偏移估计的范围为(-0. 5,+0. 5),为了提高小数倍频率偏移估计精度,可取多个小数倍频率偏移估计结果的平均值。 [0106] Since Z (·) in cycle 2 π, so a small multiple of the frequency offset estimation range (-0. 5 + 0. 5), in order to improve the accuracy of a small multiple of the frequency offset estimation, preferably a multi- a small multiple of the frequency offset estimation results averaged.

[0107] 步骤7 :估计各中继与目的端之间的整数倍频率偏移。 [0107] Step 7: estimates an integer multiple of the frequency between the relay and the destination offset.

[0108] 7a)定义各中继和目的端之间的整数倍频率偏移估计函数 An integer multiple of the frequency between the [0108] 7a) defines the relay and the destination offset estimation function

[0109] 由于定时偏移引起的接收信号的相位旋转会严重影响整数倍频率偏移估计性能, 为了消除这一影响,采用分段相关来完成整数倍频率偏移估计,定义第i个中继与目的端之间的整数倍频率偏移估计函数为: [0109] Since a serious impact due to the timing offset of the received signal phase rotation of an integral multiple of the frequency offset estimation performance, in order to eliminate this effect, the use of an integer multiple of the segment associated to complete the frequency offset estimation, the i-th relay defined integer multiple of a frequency offset estimation between the destination function:

[0110] [0110]

Figure CN102143102AD00112

[0111] 其中,i为中继序号,队为分段移动相关起始位置,G为分段数,W为每段数据点数, 且G .WSK-Ny g为段号,w为段内数据序号,b为分段移动相关起始位置偏移量,Ψ为整数倍频率偏移估计范围,R1G-D · K+Ne+(gl) · ff+w+b)为接收到的第一个训练符号在第(i-1) -K+Ne+(gl) · W+w+b个子载波上的数据。 [0111] where, i is the relay number, team-related initial position to move the segment, G is the number of segments, W data points for each segment, and G .WSK-Ny g of segment number, w is the data segment number, b is related to a movement start position of the segment offset, Ψ offset estimation range is an integer multiple of the frequency, R1G-D · K + Ne + (gl) · ff + w + b) is the first training received symbol of the (i-1) -K + Ne · W w b data on subcarriers + + + (gl).

[0112] 7b)估计各中继和目的端之间的整数倍频率偏移 [0112] 7b) estimates an integer multiple of the frequency between the relay and the destination offset

[0113] 当整数倍频率偏移估计函数Ti (b)取到最大值时所对应的b,即为第i个中继和目的端之间的整数倍频率偏移估计,因此第i个中继和目的端之间的整数倍频率偏移估计为: [0113] When an integer multiple of the frequency offset estimation function Ti (b) corresponding to the maximum time taken to, b, is the i-th integral multiple of the frequency between the relay and the destination offset estimation, and therefore in the i-th an integer multiple of the frequency between the relay and the destination offset estimation is:

[0114] [0114]

Figure CN102143102AD00113

[0115] 步骤8 :计算各中继与目的端之间的频率偏移估计值。 [0115] Step 8: calculating frequency between the relay and the destination offset estimated value.

[0116] 将各中继与目的端之间的小数倍频率偏移t和整数倍频率偏移^相加,得到各中继与目的端之间的频率偏移估计•丄=Z1^flj,! = 1,2,..., m。 [0116] The small multiple of the frequency between the relay and the destination offset t ^ and integer frequency offset is added to obtain a frequency offset between the relay and the destination estimated • Shang = Z1 ^ flj ,! = 1,2, ..., m.

[0117] 本发明的效果可以通过以下实验进一步说明。 [0117] The effect of the present invention can be further illustrated by the following experiment.

[0118] 一.实验环境 [01] I. experimental environment

[0119] 本实验针对具体实施方式所述的定时和频率偏移估计方法进行了计算机仿真,这里以文献1,即2009 年Yusi Cheng 等在“Proceedings of the 2009 IEEE 70th Vehicular Technology Conference”(第70 届IEEE VTC 国际会议)(2009 年)发表的"Preamble design and synchronization algorithm for cooperative relay systems. ” ( 〈〈ttl、作分集系统中的训练序列设计及同步算法研究》)中的定时和频率偏移估计方法作为参考。 [0119] The present experiment offset estimation method for the timing and frequency of the specific embodiments of the computer simulation, where the literature 1, 2009, Yusi Cheng et al "Proceedings of the 2009 IEEE 70th Vehicular Technology Conference" (70th session of the international Conference on IEEE VTC) (2009) published "Preamble design and synchronization algorithm for cooperative relay systems." (<< ttl, research training sequence set design systems and algorithms for synchronization points ") in the timing and frequency offsets estimation method as a reference.

[0120] 仿真参数设置如下:协作分集OFDM系统采用2个中继,它们到达目的端的时间延迟分别为0μ s和5μ s,用子载波间隔归一化的频率偏移分别为2. 7和1. 1,OFDM带宽为2. 048MHz,包含2048个子载波,系统循环前缀长度为128,本发明伪随机序列采用长度为1023的Gold序列,细定时偏移估计中分段数H = 6,每段数据点数V = 20,整数倍频率偏移估计中分段数G = 40,每段数据点数W = 4,文献1方案选取参数=5114¾, =513, Δ =4。 [0120] The simulation parameters are as follows: cooperative diversity OFDM system using two repeaters, they reached the destination and a time delay and 0μ s 5μ s, respectively, with a subcarrier spacing normalized frequency offset, respectively 2.7 and 1 . 1, OFDM bandwidth 2. 048MHz, comprising 2048 subcarriers, cyclic prefix length for the system 128, the present invention uses a pseudo-random sequence of Gold sequences of length 1023, a fine timing offset estimation division number H = 6, each segment data points V = 20, an integral multiple of the number of segments in the frequency offset estimation G = 40, each piece of data points W = 4, the program selection parameter Document 1 = 5114¾, = 513, Δ = 4. 信道采用多径衰落模型,路径数为7,路径时延在0〜30 μ s等间隔分布,功率时延分布服从指数衰减,均方根时延扩展为7 μ S。 Using the multipath fading channel model, the path number 7, the path in a delay profile 0~30 μ s intervals, the power delay profile exponential decay, rms delay spread is 7 μ S.

[0121] 二.实验内容与结果 [0121] II. Experimental results with the content

[0122] 实验一:定时偏移估计性能的仿真 [0122] Experiment 1: Simulation timing offset estimation performance

[0123] 本实验在多径信道环境下,对具体实施方式所述的定时偏移估计方法进行了计算机仿真,其结果如表1和表2所示。 [0123] This experiment in multipath channel environment, the timing offset estimation method of the specific embodiments of computer simulation, and the results shown in Table 1 and Table 2. 其中表1是采用文献1定时偏移估计方法时,两个中继与目的端间定时偏移估计误差,表2是采用本发明定时偏移估计方法时,两个中继与目的端间定时偏移估计误差。 Table 1 is employed wherein the timing offset estimation method of Document 1, between two relay and the destination end timing offset estimation error, Table 2 is the use of timing offset estimation method of the present invention, between the relay and the destination end timing of two offset estimation error.

[0124] 由表1和表2可以看出,从3dB到lldB,本发明定时偏移估计方法的估计误差平均值和均方误差均为0,显然小于文献1方案,因而具有更好的定时偏移估计性能。 [0124] As can be seen from Table 2 and Table 1, from 3dB to LLDB, the present invention is the timing offset estimation method and the estimation error of the mean square error are both 0, 1 is obviously less than Document embodiment, and thus has better timing offset estimation performance.

[0125] 表1文献1定时偏移估计性能 [0125] Table 1 Document 1 timing offset estimation performance

[0126] [0126]

信噪比(dB) 第1个中继与目的端间定时偏移估计误差 第2个中继与目的端间定时偏移估计误差 均值 均方误差 均值 均方误差1 4.94 6.04X101 -2.53 3.04X1013 4.63 5.73X101 -2.46 2.95X1015 4.55 5.65X101 -2.23 2.68X1017 4.36 5.46X101 -2.14 2.57X1019 4.23 5.33X101 -1.96 2.35X10111 4.09 5.19X101 -1.69 2.03X101 SNR (dB) of a timing offset between the relay and the destination estimation error between the second relay and the destination error of the mean timing offset estimation mean square error of the mean square error are 1 4.94 6.04X101 -2.53 3.04X1013 4.63 5.73X101 -2.46 2.95X1015 4.55 5.65X101 -2.23 2.68X1017 4.36 5.46X101 -2.14 2.57X1019 4.23 5.33X101 -1.96 2.35X10111 4.09 5.19X101 -1.69 2.03X101

[0127] 表2本发明定时偏移估计性能[0128] [0127] Table 2 timing offset estimation performance of the present invention [0128]

Figure CN102143102AD00131

[0129] 实验二:频率偏移估计性能的仿真 [0129] Experiment II: frequency offset estimation performance simulation

[0130] 本实验在多径信道环境下,对具体实施方式所述的频率偏移估计方法进行了计算机仿真,其结果如图6所示。 [0130] This experiment in multipath channel environment, offset estimation method of computer simulation of the frequency of specific embodiments, the results shown in Figure 6. 其中图6(a)是第1个中继与目的端间频率偏移估计均方误差曲线,图6(b)是第2个中继与目的端间频率偏移估计均方误差曲线。 Wherein FIG. 6 (a) is the first one between the relay and the destination frequency offset estimation mean square error curve of FIG. 6 (b) is between the second relay and the destination frequency offset estimation mean square error curve.

[0131] 由图6显然看出,本发明频率偏移估计的均方误差小于文献1频率偏移估计的均方误差,因而具有更好的频率偏移估计性能。 [0131] As apparent from FIG. 6, the frequency offset estimation according to the present invention, the mean square error less than 1 Document frequency offset estimation mean square error, hence having a better frequency offset estimation performance.

Claims (4)

  1. 1. 一种基于导频设计的协作分集OFDM定时偏移估计方法,包括以下步骤: (1)设计第i个中继的时域训练序列P^两个相同的训练符号(^构成,即Pi= [Ci Ci], Ci = [Ci,0, cia, Λ,Ci,N_J对应的频域训练符号为: Zi =[^0,ZiuZl2A ,Zik^3O]丄 丄9 乙?····? Ill其中,N为正交频分复用OFDM子载波数,Zia, Zi,2, A5Zi,κ是取值为+1或_1的伪随机序列,K为伪随机序列的长度,且K彡N/m, m为中继个数;(2)每个中继节点同时向目的端发送训练序列Pi,i = l,2,....,m。⑶目的端对接收信号r⑷=^el2mfl 'N · TMf) · Pt(s - ^ ~τ') + “⑷中长度为Ν/2-1、间隔为3Ν/2的两个数据块进行移动共轭对称相关,以计算中继和目的端之间的粗定时偏移之:其中,q为移动共轭相关起始位置,U为从q算起的数据序号,i为中继序号,Li为中继i和目的端之间信道响应的路径总数,1为路径序号,hi(l)为第1条路径的复增益,< A design based on the pilot offset cooperative diversity OFDM method of timing estimation, comprising the steps of: (1) Design of the i-th relay time domain training sequence P ^ two identical training symbols (^ configuration, i.e., Pi = [Ci Ci], Ci = [Ci, 0, cia, Λ, Ci, N_J corresponding frequency domain training symbols as: Zi = [^ 0, ZiuZl2A, Zik ^ 3O] Shang Shang 9 ···· b?? Ill where, N is the orthogonal frequency division multiplexing, OFDM, the number of subcarriers, Zia, Zi, 2, A5Zi, κ is a value of +1 or pseudorandom sequence _1, K is the length of the pseudo-random sequence, and a K San N / m, m is the number of repeaters; (2) simultaneously transmitting each relay node to the destination training sequence Pi, i = l, 2, ...., m.⑶ the destination of the received signal r⑷ = ^ el2mfl 'N · TMf) · Pt (s - ^ ~ τ') + "⑷ length of Ν / 2-1, to move two spacing blocks 3Ν / 2 conjugate symmetry-related, and to calculate the relay coarse timing offsets between the destination: wherein, q is related to the starting position moves conjugate, U q counting from the data number, i is a relay number, Li is a channel between the relay and the destination i the total number of channel response, the path number 1, hi (l) is the complex gain of the 1st path, < 第1条路径用采样周期归一化的路径时延,fi为中继i和目的端之间用子载波间隔归一化的频率偏移,ε i为中继i和目的端之间用采样周期归一化的定时偏移,η (s)是均值为0, 方差为N0的加性高斯白噪声,e = 2. 71828182……为自然常数,j为虚数单位,j2 = _1,π =3. 1415926……为圆周率,s = 1,2,……表示接收信号的序号;(4)目的端进一步对接收信号Hs)与训练符号Ci进行分段移动相关,计算各中继与目的端之间的细定时偏移其中,H为分段数,V为每段数据点数,且H · V < N,η为段号,ν为段内数据序号,d为分段移动相关起始位置的序号,Ω为分段移动相关的移动范围;(5)将各中继与目的端之间的细定时偏移总,/和粗定时偏移之相加得到各中继与目的端之间的定时偏移估计A =Kf, i = 1,2,. . .,m。 The 1st path skew normalized with the sampling period, fi i between the relay and the destination offset subcarriers normalized frequency intervals, ε i i between the relay and the destination sampling a timing offset period normalized, η (s) is zero mean and variance N0 is the additive white Gaussian noise, e = 2. 71828182 ...... is a natural constant, j is the imaginary unit, j2 = _1, π = ...... pi is 3.1415926, s = 1,2, ...... represents a sequence number of the received signal; (4) further receives the destination signal Hs) and segmented training symbols Ci movement relative, calculate the relay and the destination end wherein the timing offset between the fine, H is the number of segments, V data points for each segment and the H · V <N, η is the segment number, the data segment number v, d is related to the segment start position the number, [Omega] is related to a movement of the segment movement range; (5) between the fine and the destination relay total timing offset, / and addition of coarse timing offset obtained between the relay and the destination end timing offset estimation a = Kf, i = 1,2 ,..., m.
  2. 2. 一种基于导频设计的协作分集OFDM频率偏移估计方法,包括以下步骤: 1)设计第i个中继的时域训练序列Pi由两个相同的训练符号Ci构成,即Pi= [Ci Ci], Ci = [Ci,0, cia, Λ,Ci,N_J对应的频域训练符号为Zi Z11,Z12A ,ZlK,^3O]丄 丄9 乙? A design based on the pilot offset cooperative diversity OFDM frequency estimation method, comprising the steps of: a) Design of the i-th time domain training sequence relay Pi is composed of two identical training symbols Ci, i.e., Pi = [ Ci Ci], Ci = [Ci, 0, cia, Λ, Ci, N_J corresponding frequency domain training symbols Zi Z11, Z12A, ZlK, ^ 3O] Shang Shang acetate 9? ····? ????? Ill其中,N为正交频分复用OFDM子载波数,Zia, Zi,2, A5Zi,κ是取值为+1或_1的伪随机序列,K为伪随机序列的长度,且K彡N/m, m为中继个数;2)每个中继节点同时向目的端发送训练序列Pi,i = l,2,....,m;sl f = argmax^ γ^τ{εε+ά + {η-\)·Η + ν)·cl (n_V).H+v \ de Ω3)目的端对接收信号r⑷=Y/娜'N · Yhl (/) · Pl(s - S1 -T11) + ;7⑷中长度为N/2-1、间隔为3N/2的两个数据块进行移动共轭对称相关,以计算中继和目的端之间的粗定时偏移之:其中,q为移动共轭相关起始位置,U为从q算起的数据序号,i为中继序号,Li为中继i和目的端之间信道响应的路径总数,1为路径序号,hi(l)为第1条路径的复增益,<为第1条路径用采样周期归一化的路径时延,fi为中继i和目的端之间用子载波间隔归一化的频率偏移,ε i为中继i和目的端之间用采样周期归一化的定时偏移,η (s)是均值为0,方差为N0的 Ill where, N is the orthogonal frequency division multiplexing, OFDM, the number of subcarriers, Zia, Zi, 2, A5Zi, κ is a value of +1 or pseudorandom sequence _1, K is the length of the pseudo-random sequence, and a K San N / m, m is the number of the relay; 2) while each relay node transmits a training sequence Pi, i = l to the destination, 2, ...., m; sl f = argmax ^ γ ^ τ {εε + ά + {η - \) · Η + ν) · cl (n_V) .H + v \ de Ω3) the destination of the received signal r⑷ = Y / Na 'N · Yhl (/) · Pl (s - S1 - T11) +; 7⑷ of length N / 2-1, to move two spacing blocks 3N / 2 conjugate symmetry correlation, to calculate a coarse timing offsets between the relay and the destination end: wherein, q conjugate the relevant mobile start position, U q counting from the data number, the serial number i of the relay, Li is the total number of paths i and a channel between the relay destination of the response, the path number 1, hi (l) is a complex gain of the 1st path, <paths for the article 1 sampling period normalized path delay, Fi normalized frequency offset between i and the destination relay sub-carrier spacing, i [epsilon] i between the relay and the destination normalized timing offset of a sampling period, η (s) is the mean of 0 and variance of N0 性高斯白噪声,e = 2. 71828182……为自然常数,j为虚数单位,j2 = -l, ^ = 3. 1415926……为圆周率,s = 1,2,……表示接收信号的序号;4)目的端进一步对接收信号Hs)与训练符号Ci进行分段移动相关,计算各中继与目的端之间的细定时偏移其中,H为分段数,V为每段数据点数,且H · V < N,η为段号,ν为段内数据序号,d为分段移动相关起始位置偏移量,Ω为分段移动相关的移动范围;5)将各中继与目的端之间的细定时偏移和粗定时偏移之相加得到各中继与目的端之间的定时偏移估计A =Kf, i = 1,2,... ,m;6)在步骤幻的基础上,目的端利用接收信号在频域对应子载波上的相位差,计算各中继与目的端之间的小数倍频率偏移又,;7)目的端对接收信号Hs)在频域分别与&,i = l,2,...,m进行分段相关,计算各中继与目的端之间的整数倍频率偏移}、c ;8)将各中继与目的端 White Gaussian noise, e = 2. 71828182 ...... is a natural constant, j is the imaginary unit, j2 = -l, ^ = 3. 1415926 ...... is pi, s = 1,2, ...... represents a sequence number of the received signal; 4) further receives the destination signal Hs) and segmented training symbols Ci movement correlation, between the fine calculated for each timing offset relay and the destination where, H is the number of segments, V data points for each segment, and H · V <N, η is the segment number, ν within the data segment number, d is related to a movement start position of the segment offset, Ω is the movement of the moving range of the associated segment; 5) of each relay and the destination end fine timing offset between the timing offset and the addition of the crude obtained timing offset between the relay and the destination estimated a = Kf, i = 1,2, ..., m; 6) at step magic based on the destination using the received signal phase difference in the frequency domain corresponding to subcarriers, calculate a small multiple of the frequency offset between the relay and the destination end and,; 7) the destination of the received signal Hs) at a frequency domain respectively &, i = l, 2, ..., m segmented correlation, calculating an integral multiple of a frequency between the relay and the destination offset}, c; 8) each of the relay and the destination end 间的小数倍频率偏移和整数倍频率偏移加得到各中继与目的端之间的频率偏移估计:HKf'i = 1,2,...,m。 Small multiple of the frequency offset between the frequency offset and obtained by adding an integer multiple of a frequency offset between the relay and the destination estimated: HKf'i = 1,2, ..., m.
  3. 3.根据权利要求2所述的方法,其中步骤6)所述的计算各中继与目的端之间的小数倍频率偏移^·,按如下公式计算:其中Θ (i)为第i个中继训练符号的频域子载波集合,a为子载波序号,Z ( ·)为求角度函数,R1(B)为接收到的第一个训练符号在第a个子载波上的数据,R2(a)为接收到的第二个训练符号在第a个子载波上的数据;小数倍频率偏移估计值取多个小数倍频率偏移估计结果的平均值。 3. The method according to claim 2, a small multiple of the frequency between the relay and the destination, wherein said calculating step 6) offset * ^, calculated as follows: where [Theta] (i) is the i frequency domain subcarrier set relay training symbol, a is the subcarrier index, Z (·) is a function of the angle demand, R1 (B) for the received data in the first training symbol on a first sub-carrier, R2 of (a) the received data symbols in the second training on a first subcarrier; small multiple of the average value of frequency offset estimation value takes a plurality of small multiple of the frequency offset estimation result.
  4. 4.根据权利要求2所述的方法,其中步骤7)所述的计算各中继与目的端之间的整数倍sl f = argmax^ Υ^τ{εε+ά + {η-\)·Η + ν)·cl (n_V).H+v \ de Ω频率偏移^^,按如下公式计算:(GW ΊL=呵^l^iRM-^'K + N^ig-^-W + w + b)·Z^ be Ψ[w=l J其中,i为中继序号,队为分段移动相关起始位置,G为分段数,W为每段数据点数,且GK K-Ne, g为段号,w为段内数据序号,b为分段移动相关起始位置偏移量,Ψ为整数倍频率偏移估计范围,R1(GI) · K+Ne+(gl) · ff+w+b)为接收到的第一个训练符号在第(i-1) · K+Ne+(gl) · ff+w+b个子载波上的数据。 4. The method according to claim 2, integral multiple sl f between the relay and the destination, wherein said calculating step 7) = argmax ^ Υ ^ τ {εε + ά + {η - \) · Η + ν) · cl (n_V) .H + v \ de Ω ^^ frequency offset, is calculated as follows: (GW ΊL = ha ^ l ^ iRM - ^ 'K + N ^ ig - ^ - W + w + b) · Z ^ be Ψ [w = l J where, i is the relay number, team-related initial position to move the segment, G is the number of segments, W data points for each segment, and GK K-Ne, g number of segments, w is the number of data segments, b is the starting position of the segment movement relative offset, Ψ offset estimation range is an integer multiple of the frequency, R1 (GI) · K + Ne + (gl) · ff + w + b) ff w data received at the first training symbol (i-1) · K + Ne + (gl) · + + b on the subcarriers.
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