OFDM系统中降低峰均功率比技术的研究
摘要
正交频分复用(OFDM)是一种特殊的多载波传输技术。它的基本思想是将所要传输的高速数据流通过串/并转换,变成多路并行的若干个子数据流,每个子数据流具有比发送端原始数据流低得多的传输速率,然后用这些子数据流去并行调制若干个相互正交的载波,最后再合并成一个OFDM符号进行传输。
OFDM技术的优点在于它可以提供更高的频谱效率、更强的抗符号间干扰能力和更好的抗多径衰落能力。但是,OFDM技术也有一些缺点,例如对频偏的敏感性、较高的峰均功率比等,这些问题限制了OFDM技术的发展和应用。
本文论述了移动通信的发展概况,OFDM系统的基本原理、发展概况、主要技术及优缺点,重点论述了OFDM系统中降低PAPR的方法。目前,国内外降低PAPR技术的方法主要包括信号畸变类方法、编码类方法和概率类方法。其中:信号畸变类方法直接在OFDM信号幅度峰值或其附近进行非线性操作来降低信号的PAPR值;编码类方法是通过限制可用于传输的信号码集来降低PAPR,其核心思想是运用一种特殊的前向纠错编码技术来剔除高PAPR的OFDM信号;概率类方法着眼于降低OFDM信号峰值出现的概率。
针对PTS全搜索算法计算复杂度过大,而传统的PTS迭代算法性能较差的缺点,本文提出了一种PTS改进算法,仿真结果表明,该算法很好地折衷了OFDM系统的PAPR性能和计算的复杂度。
针对传统的输入序列定标全搜索算法计算复杂度过大的缺点,本文提出了一种简化算法,该算法是通过施加终止门限并进行迭代计算实现的,仿真结果验证了该算法的有效性。
Orthogonal Frequency Division Modulation ( OFDM ) is a special multi-carrier technology which is to split high speed data flow into several sub-flow by using an A/D converter Every sub-flow has a much lower speed than the original data flow from the source. The sub-flows are used to modulate the orthogonal carriers and compose an OFDM symbol for transmission.
The advantages of OFDM technology are higher spectrum efficiency, anti-interference among symbols and anti-dissipation of multi-path. OFDM also has some disadvantages such as sensitive to the inaccurate frequency and average high-peak power ratio, which limit the development and application of OFDM.
This article discusses the development of mobile communications, OFDM system, the basic principles of development, and the main technical advantages and disadvantages, focusing on reducing PAPR in the OFDM system. At present, the main methods of reducing the PAPR include the types of signal distortion methods directly or near the peak rate for non-linear operations to reduce the PAPR, types of coding methods limiting the number of letters set to reduce the PAPR and types of methods of probability at home and abroad. Its core idea is to use a special kind of forward error correction coding technology to remove high PAPR of OFDM signal; probability category methods focus on ways to reduce OFDM signal peak probability.
As entire searching algorithm of PTS for computing is much too complex, and traditional iterative algorithm of PTS is so poor, this paper provided an improved PTS algorithm. The simulation results show that it is a good compromise between the performance and computing complexity of PAPR of OFDM system.
As the entire search algorithm of input sequence envelope scaling is too complex, this paper provided a simplified algorithm, which is realized through imposing the termination of the threshold and the iterative calculations, the simulation results show the effectiveness of the algorithm.
OFDM技术的优点在于它可以提供更高的频谱效率、更强的抗符号间干扰能力和更好的抗多径衰落能力。但是,OFDM技术也有一些缺点,例如对频偏的敏感性、较高的峰均功率比等,这些问题限制了OFDM技术的发展和应用。
本文论述了移动通信的发展概况,OFDM系统的基本原理、发展概况、主要技术及优缺点,重点论述了OFDM系统中降低PAPR的方法。目前,国内外降低PAPR技术的方法主要包括信号畸变类方法、编码类方法和概率类方法。其中:信号畸变类方法直接在OFDM信号幅度峰值或其附近进行非线性操作来降低信号的PAPR值;编码类方法是通过限制可用于传输的信号码集来降低PAPR,其核心思想是运用一种特殊的前向纠错编码技术来剔除高PAPR的OFDM信号;概率类方法着眼于降低OFDM信号峰值出现的概率。
针对PTS全搜索算法计算复杂度过大,而传统的PTS迭代算法性能较差的缺点,本文提出了一种PTS改进算法,仿真结果表明,该算法很好地折衷了OFDM系统的PAPR性能和计算的复杂度。
针对传统的输入序列定标全搜索算法计算复杂度过大的缺点,本文提出了一种简化算法,该算法是通过施加终止门限并进行迭代计算实现的,仿真结果验证了该算法的有效性。
Orthogonal Frequency Division Modulation ( OFDM ) is a special multi-carrier technology which is to split high speed data flow into several sub-flow by using an A/D converter Every sub-flow has a much lower speed than the original data flow from the source. The sub-flows are used to modulate the orthogonal carriers and compose an OFDM symbol for transmission.
The advantages of OFDM technology are higher spectrum efficiency, anti-interference among symbols and anti-dissipation of multi-path. OFDM also has some disadvantages such as sensitive to the inaccurate frequency and average high-peak power ratio, which limit the development and application of OFDM.
This article discusses the development of mobile communications, OFDM system, the basic principles of development, and the main technical advantages and disadvantages, focusing on reducing PAPR in the OFDM system. At present, the main methods of reducing the PAPR include the types of signal distortion methods directly or near the peak rate for non-linear operations to reduce the PAPR, types of coding methods limiting the number of letters set to reduce the PAPR and types of methods of probability at home and abroad. Its core idea is to use a special kind of forward error correction coding technology to remove high PAPR of OFDM signal; probability category methods focus on ways to reduce OFDM signal peak probability.
As entire searching algorithm of PTS for computing is much too complex, and traditional iterative algorithm of PTS is so poor, this paper provided an improved PTS algorithm. The simulation results show that it is a good compromise between the performance and computing complexity of PAPR of OFDM system.
As the entire search algorithm of input sequence envelope scaling is too complex, this paper provided a simplified algorithm, which is realized through imposing the termination of the threshold and the iterative calculations, the simulation results show the effectiveness of the algorithm.
引文
[1]王文博,郑侃,宽带无线通信OFDM技术,人民邮电出版社,2003
[2]汪裕民,OFDM的关键技术,机械工业出版社,2007
[3] Q. Bi, G.I. Zysman, H. Menkes, Wireless Mobile Communications at the Start of the 21’Century, IEEE Communications Magazine, Jan.2001:16-110.
[4] Hwang C S.“Peak Power Reduction Method for Multi-carrier Transmission”,Electronics Letter,2001,37(17):1075-1077
[5] Sathananthan K, Tellambura C. Coding to reduce both PAPR and PICR of an OFDM, signals. IEEE Communications Letters,2002,6(8):316-318
[6] S. H. Muller and J. B. Huber,“A comparison of Peak Power Reduction Schemes for OFDM”,GLOBECOM,IEEE,Vol.1,Nov.1997,pp.l-5
[7] C. Tellambura.Comment on Multicarrier transmission peak-to-average power reduction using simple block code. Electronics Letters,Aug.1998,34(17)
[8]尹长川等著,多载波宽带移动通信技术,北京邮电大学出版社,2004
[9] Franziskus Bauer, Arnaud Guéguen, Sylvie Mayrargue, et al.. Synthesis Report on worldwide research on 4G systems. European Commission IST-2001-32620 MATRICE Deliverable D1.4
[10] R. W. Bauml,R. Fischer,J. B. Huber. Reducing the peak-to-average power ratio of multi-carrier modulation by selected mapping. Electronics Letters, 1996, 32(22):2056-5057
[11] S. H. Muller and J. B. Huber. OFDM with reduced Peak-to-average power ratio by optimum combination of Partial transmit sequence. Electronics Letters, Feb. 1997,33(5):5
[12] S. G. Kang, J. Kim. A novel sub-block Partition scheme for partial transmit sequence OFDM. IEEE Trans. on Broadcasting,Step.1999,45(3):333-338
[13] P.Foomooljareon,W.A.C.Fernando,K.M.Ahmed.PAPR Reduction of OFDM Systems Using Input Sequence Envelop Scaling.IEEE Vehicular Technology Conference,2003,57(2):1243-1247
[14]曹达仲,数字移动通信及ISDN,天津大学出版社,1997
[15]张平,第四代移动通信系统的关键技术及分析,电信科学,2002, 18:30-34
[16]袁贵民,刘文霞等,移动通信,北京师范大学出版社,2007
[17]陈柏南,周跃峰,胡亮亮等,OFDM系统中峰均比降低算法研究.通信技术,2003,(7):29
[18]纪红,佟学俭等,OFDM:适合于未来移动通信系统的解决方案,无线电工程,2002,32 (7) : 17-20.
[19]侯春萍,沈保锁,现代通信原理,天津大学科技出版社,1999
[20] S. Ben Slimane , Peak-to-Average Power Ratio Reduction of OFDM Signals using Broadband Pulse Shaping,Vehicular Technology Conference,2002,Proceedings.VTC2002-Fall.2002 IEEE 56th,2002,2:889-893
[21] S. Ben Slimane, Peak-to-Average Power Ratio Reduction of OFDM Signals using Pulse Shaping, Global Telecommunication Conference,2000. CLOBECOM’00.IEEE,2000,3:1412-1416
[22] Hideki Ochiai.“On the distribution of the peak-to-average power ratio in OFDM signals”, IEEE Trans COM,2001,49(2):282-289
[23] Jayalath A D S, Tellambura C.“Adaptive PTS approach for reduction of peak-to-average power ratio of OFDM signal”, Electronic Lett.,2000, 36(14):1226-1228
[24] Sung-Eun Park, et al.“Tone Reservation method for PAPR Reduction scheme”, IEEE 802.16e-03/60,2003
[25] J.Tellado.“Peak to Average Power Reduction for Multicarrier Modulation”, Ph.D.dissertation, Stanford Univ.,2000
[26]魏克军,益晓新,一种采用压扩算法降低OFDM信号PAPR的新方法.电视技术,2003,(2):14-16
[27]佟学俭,罗涛,移动通信技术原理与应用,人民邮电出版社,2003
[28]陈怀琛,吴大正,高西全,MATLAB及在电子信息课程中的应用,电子工业出版社,2003
[29]冯佩珍,英汉现代通信技术缩略语词典,科学出版社,1999
[30]胡金海,英汉电信词汇缩略语词典,哈尔滨工程大学出版社,1999
[2]汪裕民,OFDM的关键技术,机械工业出版社,2007
[3] Q. Bi, G.I. Zysman, H. Menkes, Wireless Mobile Communications at the Start of the 21’Century, IEEE Communications Magazine, Jan.2001:16-110.
[4] Hwang C S.“Peak Power Reduction Method for Multi-carrier Transmission”,Electronics Letter,2001,37(17):1075-1077
[5] Sathananthan K, Tellambura C. Coding to reduce both PAPR and PICR of an OFDM, signals. IEEE Communications Letters,2002,6(8):316-318
[6] S. H. Muller and J. B. Huber,“A comparison of Peak Power Reduction Schemes for OFDM”,GLOBECOM,IEEE,Vol.1,Nov.1997,pp.l-5
[7] C. Tellambura.Comment on Multicarrier transmission peak-to-average power reduction using simple block code. Electronics Letters,Aug.1998,34(17)
[8]尹长川等著,多载波宽带移动通信技术,北京邮电大学出版社,2004
[9] Franziskus Bauer, Arnaud Guéguen, Sylvie Mayrargue, et al.. Synthesis Report on worldwide research on 4G systems. European Commission IST-2001-32620 MATRICE Deliverable D1.4
[10] R. W. Bauml,R. Fischer,J. B. Huber. Reducing the peak-to-average power ratio of multi-carrier modulation by selected mapping. Electronics Letters, 1996, 32(22):2056-5057
[11] S. H. Muller and J. B. Huber. OFDM with reduced Peak-to-average power ratio by optimum combination of Partial transmit sequence. Electronics Letters, Feb. 1997,33(5):5
[12] S. G. Kang, J. Kim. A novel sub-block Partition scheme for partial transmit sequence OFDM. IEEE Trans. on Broadcasting,Step.1999,45(3):333-338
[13] P.Foomooljareon,W.A.C.Fernando,K.M.Ahmed.PAPR Reduction of OFDM Systems Using Input Sequence Envelop Scaling.IEEE Vehicular Technology Conference,2003,57(2):1243-1247
[14]曹达仲,数字移动通信及ISDN,天津大学出版社,1997
[15]张平,第四代移动通信系统的关键技术及分析,电信科学,2002, 18:30-34
[16]袁贵民,刘文霞等,移动通信,北京师范大学出版社,2007
[17]陈柏南,周跃峰,胡亮亮等,OFDM系统中峰均比降低算法研究.通信技术,2003,(7):29
[18]纪红,佟学俭等,OFDM:适合于未来移动通信系统的解决方案,无线电工程,2002,32 (7) : 17-20.
[19]侯春萍,沈保锁,现代通信原理,天津大学科技出版社,1999
[20] S. Ben Slimane , Peak-to-Average Power Ratio Reduction of OFDM Signals using Broadband Pulse Shaping,Vehicular Technology Conference,2002,Proceedings.VTC2002-Fall.2002 IEEE 56th,2002,2:889-893
[21] S. Ben Slimane, Peak-to-Average Power Ratio Reduction of OFDM Signals using Pulse Shaping, Global Telecommunication Conference,2000. CLOBECOM’00.IEEE,2000,3:1412-1416
[22] Hideki Ochiai.“On the distribution of the peak-to-average power ratio in OFDM signals”, IEEE Trans COM,2001,49(2):282-289
[23] Jayalath A D S, Tellambura C.“Adaptive PTS approach for reduction of peak-to-average power ratio of OFDM signal”, Electronic Lett.,2000, 36(14):1226-1228
[24] Sung-Eun Park, et al.“Tone Reservation method for PAPR Reduction scheme”, IEEE 802.16e-03/60,2003
[25] J.Tellado.“Peak to Average Power Reduction for Multicarrier Modulation”, Ph.D.dissertation, Stanford Univ.,2000
[26]魏克军,益晓新,一种采用压扩算法降低OFDM信号PAPR的新方法.电视技术,2003,(2):14-16
[27]佟学俭,罗涛,移动通信技术原理与应用,人民邮电出版社,2003
[28]陈怀琛,吴大正,高西全,MATLAB及在电子信息课程中的应用,电子工业出版社,2003
[29]冯佩珍,英汉现代通信技术缩略语词典,科学出版社,1999
[30]胡金海,英汉电信词汇缩略语词典,哈尔滨工程大学出版社,1999