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      UWB多徑信道調(diào)制方式的誤碼率分析

      2015-11-02 10:45:06楊英杰王曉峰曲朝陽(yáng)張文龍
      關(guān)鍵詞:誤碼率接收機(jī)信噪比

      楊英杰, 王曉峰, 曲朝陽(yáng), 張文龍

      (東北電力大學(xué)信息工程學(xué)院,吉林 132012)

      UWB多徑信道調(diào)制方式的誤碼率分析

      楊英杰, 王曉峰*, 曲朝陽(yáng), 張文龍

      (東北電力大學(xué)信息工程學(xué)院,吉林 132012)

      為了研究Ultra-Wideband(UWB)系統(tǒng)中可分辨多徑分量和不可分辨多徑分量攜帶信號(hào)的誤碼率問(wèn)題,利用Radio Activated Key Entry(RAKE)接收機(jī)的分集技術(shù),在信號(hào)發(fā)射端分別采用 Binary Phase Shift Keying (BPSK)和Pulse Position Modulation(PPM)調(diào)制方式,從這2種調(diào)制方式的解析式入手,推導(dǎo)出BPSK與PPM在可分辨和不可分辨多徑分量下誤碼率表達(dá)式,并針對(duì)在相同叉指數(shù)和信噪比下,分別對(duì)這2種多徑分量信號(hào)在不同調(diào)制方式下的誤碼率進(jìn)行仿真分析.仿真結(jié)果表明,在相同調(diào)制方式下,可分辨多徑的抗誤碼率性能要優(yōu)于不可分辨多徑的情況.而且,采用BPSK調(diào)制無(wú)論是可分辨多徑還是不可分辨多徑,在抗誤碼率性能上,均優(yōu)于PPM調(diào)制方式.

      叉指數(shù); 信噪比; RAKE接收機(jī); 二進(jìn)制相移鏈控(BPSK); 脈位調(diào)制(PPM)

      在Ultra-Wideband(UWB)系統(tǒng)中,多徑接收信號(hào)可分為2種,即可分辨信號(hào)和不可分辨信號(hào)[1].在接收過(guò)程中,由于多徑信號(hào)各分量之間相互獨(dú)立[2-3],如果一部分多徑分量處于深衰落,接收機(jī)則選擇另一部分淺衰落或未衰落的多徑分量進(jìn)行判決[4-5],則使“不可分辨”變?yōu)椤翱煞直妗?,這正是Radio Activated Key Entry (RAKE)接收機(jī)采用“分集接收”的基本思想[6-8].在實(shí)際中,如果出現(xiàn)部分多徑分量處于深衰落,則造成接收誤碼率的大幅上升,此時(shí),如能在發(fā)射端通過(guò)合理地選擇調(diào)制方式,在一定程度上控制多徑信號(hào)的衰落,進(jìn)而減小接收端的誤碼率.為此,可從2種信號(hào)的誤碼率分析入手,估計(jì)出2種信號(hào)對(duì)接收端的影響,然后再據(jù)此確定出最終的調(diào)制方式.

      類(lèi)似于數(shù)字系統(tǒng)中的脈沖調(diào)制,跳時(shí)擴(kuò)頻脈位調(diào)制(TH-PPM)與跳時(shí)擴(kuò)頻二相鍵控調(diào)制(TH-BPSK)在UWB系統(tǒng)的發(fā)射端是較為典型的調(diào)制方式[9],在一定程度上抑制了多徑信號(hào)的衰落,減小了多徑信號(hào)在接收端的誤碼率, 并且文獻(xiàn)[9]中利用歐式距離的方法估計(jì)了TH-PPM與TH-BPSK這2種調(diào)制方式的性能比較, TH-BPSK抑制衰落效果比TH-PPM高3 dB.由于這2種調(diào)制方式較為復(fù)雜,增大了在接收端對(duì)多徑信號(hào)誤碼率分析的難度, 所以基于TH-BPSK和TH-PPM調(diào)制方式,本文由2種調(diào)制的解析式, 推導(dǎo)出BPSK和PPM在可分辨多徑和不可分辨多徑情況下的誤碼率表達(dá)式,通過(guò)仿真,在發(fā)射端采用這2種調(diào)制方式, 對(duì)比分析可分辨多徑信號(hào)和不可分辨多徑信號(hào)在接收端的誤碼率情況,并在相同調(diào)制方式下, 比較可分辯多徑信號(hào)和不可分辨多徑信號(hào)的誤碼率.

      1 BPSK與PPM調(diào)制

      1.1BPSK調(diào)制誤碼率的推導(dǎo)

      對(duì)于傳統(tǒng)的RAKE接收機(jī)來(lái)說(shuō),在發(fā)射端可以采用BPSK調(diào)制或PPM調(diào)制的傳輸方式.理想的RAKE接收機(jī)等效于L階分集系統(tǒng)中的最大比合并器[10],所以,由分集系統(tǒng)的二進(jìn)制信號(hào)差錯(cuò)概率可得,當(dāng)發(fā)送BPSK調(diào)制信號(hào)時(shí),設(shè)發(fā)送符號(hào)的波形為w(t),符號(hào)長(zhǎng)度為T(mén),信道系數(shù)為al,脈沖形狀p(t),下面給出BPSK的發(fā)射信號(hào)s(t)、信道模型h(t)和接收信號(hào)r(t)的表達(dá)式[11]:

      ∵r(t)=s(t)·h(t),

      (1)

      其中,Lp為多徑數(shù)目,w為頻率選擇性信道的帶寬,m表示m個(gè)比特符號(hào),bm為第m個(gè)消息位,l為多徑信道分辯率系數(shù),多徑信道分辨率為Δ=1/w.

      在UWB系統(tǒng)中通常采用“時(shí)限脈沖”[12],所以取脈沖寬度Tp為UWB RAKE接收機(jī)多徑分辨率,為了達(dá)到最優(yōu)接收機(jī)的性能,令Δ=Tp,其能量捕獲效率η=1.

      假設(shè)BPSK調(diào)制的RAKE接收使用的模板為:

      (2)

      定義模板和發(fā)送脈沖的歸一化函數(shù)R()為:

      R()k)w′(t-l)dt.

      (3)

      假設(shè)L階的RAKE合并系數(shù)為βk,k=0,1,2,…,L-1,所對(duì)應(yīng)的第k個(gè)路徑的延時(shí)為k=ikTp.第m個(gè)比特符號(hào)的RAKE輸出為:

      (4)

      進(jìn)一步將式(1)代入式(4)中得到輸出與發(fā)射脈沖相關(guān)函數(shù)、信道關(guān)系.令Eb=R(0),式(4)可以寫(xiě)成

      (5)

      (6)

      (7)

      當(dāng)路徑不可分辨時(shí),BPSK調(diào)制的RAKE接收機(jī)誤碼率為:

      (8)

      當(dāng)取接收機(jī)多徑分辨率Tp為信道多徑分辨率Δ的整數(shù)倍,令Δ=Tp,有:

      y(mT)=

      (9)

      (10)

      其中,SNR=2Eb/N0為比特符號(hào)的信噪比.

      1.2PPM調(diào)制誤碼率的推導(dǎo)

      同樣,當(dāng)信號(hào)發(fā)射端為PPM調(diào)制時(shí),PPM發(fā)射信號(hào)s(t)、信道模型h(t)和接收信號(hào)r(t)的表達(dá)式[14]:

      ∵r(t)=s(t)·h(t),

      (11)

      其中,Ts是脈沖平均重復(fù)周期,cm是調(diào)時(shí)序列,Tc為碼片時(shí)間.

      所使用的模板波形為:

      mTs

      (12)

      定義模板和發(fā)送脈沖的歸一化函數(shù)R()為:

      R()

      (13)

      與BPSK相似,第m個(gè)比特符號(hào)的RAKE輸出為:

      (14)

      方差為:

      (15)

      當(dāng)路徑不可分辨時(shí),PPM調(diào)制的RAKE接收機(jī)誤碼率為:

      (16)

      與BPSK類(lèi)似,可分辨多徑下的誤碼率為:

      (17)

      2 誤碼率性能對(duì)比方法

      2.1可分辨多徑和不分辨見(jiàn)多徑PPM調(diào)制方式性能對(duì)比

      通過(guò)SIMULINK6.5仿真,得到2種多徑信號(hào)的性能比較,仿真條件:分別采用BPSK和PPM調(diào)制方式,總共發(fā)送100次,每次發(fā)送512 bits訓(xùn)練序列和10 000 bits數(shù)據(jù)序列,發(fā)送的波形為高斯五階脈沖,表達(dá)式為:

      (18)

      圖1、圖2分別表示在UWB可分辨多徑和不可分辨多徑信號(hào)環(huán)境下, PPM調(diào)制的RAKE接收機(jī)的性能,表1表示在相同信噪比和叉指數(shù)條件下,可分辨多徑和不可分辨多徑誤碼率的對(duì)比,結(jié)果表明,采用PPM調(diào)制,前者小于后者.

      2.2可多分辨徑和不可分辨多徑BPSK調(diào)制方式性能對(duì)比

      基于BPSK的可分辨多徑和不可分辨多徑信號(hào)調(diào)制的誤碼率性能由圖3、4所示.在相同信噪比和叉指數(shù)情況下,可分辨多徑和不可分辨多徑信號(hào)的誤碼率對(duì)比如表2所示,結(jié)果表明,采用BPSK調(diào)制,前者小于后者.

      3 結(jié)果與分析

      由4個(gè)誤碼率仿真圖(圖1~4)和表1和表2可知,當(dāng)采用PPM調(diào)制方式,信噪比SNR=20 dB,叉指數(shù)arm=8,可分辨多徑信號(hào)的誤碼率是2×10-7,不可分辨多徑信號(hào)的誤碼率是1×10-5,可分辨多徑信號(hào)的誤碼率小于不可分辨多徑信號(hào)的誤碼率,并且隨信噪比增大和叉指數(shù)的增加,可分辨多徑信號(hào)的誤碼率仍小于不可分辨多徑信號(hào)的誤碼率. 當(dāng)采用BPSK調(diào)制方式,信噪比SNR=20 dB,叉指數(shù)arm=8,可分辨多徑信號(hào)的誤碼率是3×10-7,不可分辨多徑信號(hào)的誤碼率是2×10-6,結(jié)論和PPM調(diào)制相同.對(duì)于同種多徑信號(hào)來(lái)說(shuō),從表1、表2中看出,在相同信噪比和叉指數(shù)的情況下,采用BPSK調(diào)制的信號(hào)誤碼率小于采用PPM調(diào)制的信號(hào)誤碼率.

      圖1 可分辨多徑PPM調(diào)制的性能

      Figure 1Performance of the resolvable multipath PPM modulation

      圖2 不可分辨多徑PPM調(diào)制的性能

      Figure 2Performance of the indiscernibility multipath PPM modulation

      表1PPM調(diào)制2種多徑的誤碼率對(duì)比

      Table 1Comparison of two multipath error rates of PPM modulation

      SNR/dBarm可分辨多徑誤碼率不可分辨多徑誤碼率2082×10-71×10-525123×10-122×10-8

      圖3 可分辨多徑BPSK調(diào)制的性能

      Figure 3Performance of the resolvable multipath BPSK modulation

      圖4 不可分辨多徑BPSK調(diào)制的性能

      Figure 4Performance of indiscernibility multipath BPSK modulation

      表2BPSK調(diào)制2種多徑的誤碼率對(duì)比

      Table 2Comparison of two multipath error rates of BPSK modulation

      SNR/dBarm可分辨多徑誤碼率不可分辨多徑誤碼率2083×10-72×10-625124×10-133×10-12

      無(wú)論采用哪種調(diào)制方式,就多徑信號(hào)本身而言,可分辨多徑信號(hào)和不可分辨多徑信號(hào)的誤碼率均受到信噪比的影響,但是,當(dāng)可分辨多徑信號(hào)的信號(hào)分辨率Tp為多徑信道分辨率Δ的整數(shù)倍時(shí),第m個(gè)比特符號(hào)的RAKE輸出則受到歸一化項(xiàng)系數(shù)ρ的影響,當(dāng)ρ=0,表示多徑信號(hào)之間無(wú)混疊,此時(shí),多徑信號(hào)的誤碼率最小,而不可分辨多徑信號(hào)不受歸一項(xiàng)帶來(lái)的加性影響,可使可分辨多徑信號(hào)的誤碼率小于不可分辨多徑信號(hào)的誤碼率.從調(diào)制方式上看,BPSK和PPM都受到UWB RAKE接收機(jī)多徑分辨率Tp的影響, 對(duì)于PPM調(diào)制模式,多徑信號(hào)的誤碼率還受到調(diào)時(shí)序列cm和碼片時(shí)間Tc的影響,但由于多徑信號(hào)占空比很小,調(diào)制時(shí)所需碼片時(shí)間和調(diào)時(shí)序列短[15],導(dǎo)致多徑信號(hào)的誤碼率增大.

      4 結(jié)論

      針對(duì)UWB系統(tǒng)中的可分辨多徑信號(hào)和不可分辨多徑信號(hào)誤碼率問(wèn)題,在信號(hào)發(fā)射端采用BPSK和PPM調(diào)制方式,從2種調(diào)制方式的解析式入手,推導(dǎo)出BPSK和PPM調(diào)制在可分辨多徑和不可分辨多徑情況下的誤碼率表達(dá)式,得出可行性的結(jié)論.仿真結(jié)果表明:在相同SNR和arm數(shù)的條件下,對(duì)于BPSK和PPM調(diào)制,在可分辨多徑條件下的誤碼率比不可分辨多徑的小,并且,在相同多徑信號(hào)條件下,BPSK調(diào)制的誤碼率比PPM調(diào)制的小.

      [1]王石記,沙學(xué)軍.UWB信道不同擴(kuò)展帶寬下RAKE接收性能分析[J].哈爾濱工業(yè)大學(xué)學(xué)報(bào),2008,40(2):255-258.

      Wang S J,Sha X J. Performance analysis of RAKE reception with different spreading bandwidth in UWB channels[J].Journal of Harbin Institute of Techology, 2008,40(2):255-258.

      [2]Luo Yan-Jia. Indoor positioning using UWB-IR signals in the presence of dense multipath with path overlapping[J]. IEEE Transactions on Wireless Communications,2012,11(10):3734-3743.

      [3]扈羅全,朱洪波.超寬帶室內(nèi)多徑信道隨機(jī)分析模型[J].電波科學(xué)學(xué)報(bào),2006,21(4):482-487.

      Hu L Q,Zhu H B. Stochastic calculus model for UWB indoor multipath channel[J].Chinese Journal of Radio Science,2006,21(4):482-487.

      [4]李東武,裴昌幸,何先燈,等.協(xié)作通信中一種高性能空時(shí)二維RAKE接收算法[J].天津大學(xué)學(xué)報(bào):自然科學(xué)與工程技術(shù)版,2014,47(9):778-784.

      Li D W,Pei C Q,He X D,et al. A Space-Time two dimensional rake receiving algorithm in asynchronous cooperative communications system with high performance[J].Journal of Tianjin University: Science and Technology,2014,47(9):778-784.

      [5]王杰令,劉祖軍,楊宏,等.頻率選擇性衰落信道中的RAKE合并接收方案[J].電子科技大學(xué)學(xué)報(bào),2010,39(5):662-665.

      Wang J L,Liu Z J,Yang H,et al.RAKE combining receiver in frequency selective fading channels[J]. Journal of University of Electronic Science and Thechology,2010,39(5):662-665.

      [6]Jin D P,Xiao Z Y,Zhang J Y, et al. Periodical-pilot-assisted tracking loop with RAKE combining for high rate DS-UWB receivers[C]∥2010 IEEE International Conference on Communicatins,ICC2010.Cape Town,South Africa, 2010:1-6.

      [7]肖竹,李仁發(fā),易克初. UWB多徑信道下RAKE接收和均衡的作用分析[J]. 湖南大學(xué)學(xué)報(bào):自然科學(xué)版,2013,40(4):94-99.

      Xiao Z, Li R F, Yi K C. Analysis on RAKE receiver and equalization under ultra-wideband multipath channel[J].Journal of Hunan University:Natural Sciences, 2013,40(4):94-99.

      [8]張會(huì)清,王普,高學(xué)金,等.分集接收抗多徑衰落性能及在隧道模型中仿真[J].電波科學(xué)學(xué)報(bào),2010,25(4):793-797.

      Zhang H Q,Wang P,Gao X J,et al. Ability of diversity reception technique to resist multipath decline and simulating with a tunnel model[J].Chinese Journal of Radio Science,2010,25(4):793-797.

      [9]Shaheen E M. Non-Gaussian MAI modeling to the performance of TH-BPSK/PPM UWB communication systems[C]∥2012 8th International Wireless Communications and Mobile Computing Conference. Shanghai, China, 2012:16-920.

      [10]Bobby B. Comparison the performance of free-Space optical communication with OOK and BPSK modulation under atmospheric turbulence[J]. International Journal of Engineering Science and Technology,2011,3(5):4391-4399.

      [11]盛彬,尤肖虎.非理想最大比合并的誤碼率下界[J].東南大學(xué)學(xué)報(bào):英文版,2005,21(4):379-384.

      Shen B,You X H. Lower bound on BER performance for maximal ratio combining with weighting errors[J]. Journal of Southeast University:English Edition,2005,21(4):379-384.

      [12]Baltzis K B. The rake receiver principle: Past, present and future[J]. Recent Patents on Electrical Engineering,2012,5(1):55-71.

      [13]Doukeli A P, Lioumpas A S, Karagiannidis G K,et al. Increasing the efficiency of rake receivers for ultra-wideband applications[J]. Wireless Personal Communications,2012,62(3):715-728.

      [14]Güney N, Deli? H, Alagoz F. Achievable information rates of PPM impulse radio for UWB channels and rake reception[J].IEEE Transactions on Communications,2010,58(5):1524-1535.

      [15]Guney N,Delic H,Yang L Q,et al.A general model and SINR analysis of low duty-cycle UWB access through multipath with narrowband interference and rake reception[J].IEEE Transactions on Wireless Communications,2005,4(4):1818-1833.

      【中文責(zé)編:譚春林 英文責(zé)編:肖菁】

      UWB Multipath Channel Modulation Mode Analysis of the Bit Error Rate

      Yang Yingjie, Wang Xiaofeng*, Qu Zhaoyang, Zhang Wenlong

      (College of Information Engineering,Northeast Dianli University, Jilin 132012, China)

      In order to study the problem that Ultra-Wideband (UWB)system can distinguish the multipath components and indiscernibility more carrying signals, Rake receiver diversity technology is used. In the signal transmitter, Binary Phase Shift Keying (BPSK) and Pulse Position Modulation (PPM) modulation method are used respectively. From the analytic expression of these two kinds of modulation mode,elicit BPSK and PPM in the resolvable multipath and indiscernibility multipath error rate expression are induced. For the same fork index and signal-to-noise ratio,two kinds of multipath component signals under different modulation mode of simulation analysis are conducted. The simulation results show that,under the same modulation mode,distinguish the multipath error rate resistance is superior to the indiscernibility multipath situation. No matter in distinguish multipath or indiscernibility multipath, BPSK modulation is superior to PPM modulation method on resistance error rate.

      arm; SNR; RAKE receiver; binary phase shift keying (BPSK); pulse position modulation (PPM)

      2015-03-15《華南師范大學(xué)學(xué)報(bào)(自然科學(xué)版)》網(wǎng)址:http://journal.scnu.edu.cn/n

      國(guó)家自然科學(xué)基金項(xiàng)目(51277023)

      楊英杰,副教授, Email: yyj56042@163.com.

      TN929.5

      A

      1000-5463(2015)05-0023-05

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