信号处理
信號處理
신호처리
SIGNAL PROCESSING
2014年
7期
749-765
,共17页
数字电视地面广播%相位噪声%判决反馈%公共相位误差%子载波间干扰
數字電視地麵廣播%相位譟聲%判決反饋%公共相位誤差%子載波間榦擾
수자전시지면엄파%상위조성%판결반궤%공공상위오차%자재파간간우
digital terrestrial television broadcasting (DTTB)%phase noise%decision feedback%common phase error (CPE)%inter carrier interference (ICI)
相位噪声会破坏 OFDM(Orthogonal Frequency Division Multiplex)符号内频域子载波的正交性,产生公共相位误差(CPE,Common Phase Error)和子载波间干扰(ICI,Inter-Carrier Interference),对系统性能造成严重影响。针对数字电视地面广播传输标准演进方案(DTMB-A)的相位噪声问题,本文提出了一种两步结合的相位噪声估计和消除算法。首先,利用相邻两帧的帧头符号中所包含的 PN(Pseudo Noise)序列,对帧体符号内的公共相位误差进行粗估计;随后,对帧体数据子载波进行标记,选取合适的子载波集合用于估计公共相位误差和子载波间干扰的精确结果。由此获得相位噪声频域估计结果后,通过快速傅立叶变换(FFT,Fast Fourier Transform)得到时域估计结果并进行消除。和现有基于判决反馈的相位噪声估计算法对比,本文所提算法的创新性在于采用了粗估计和精确估计结合的方法,同时利用子载波标记的方法有效降低了由于错误判决导致的误码扩散。仿真结果表明在现有算法已经不能正常工作的情况下,本文所提算法还可以有效的抑制相位噪声对系统性能的影响。
相位譟聲會破壞 OFDM(Orthogonal Frequency Division Multiplex)符號內頻域子載波的正交性,產生公共相位誤差(CPE,Common Phase Error)和子載波間榦擾(ICI,Inter-Carrier Interference),對繫統性能造成嚴重影響。針對數字電視地麵廣播傳輸標準縯進方案(DTMB-A)的相位譟聲問題,本文提齣瞭一種兩步結閤的相位譟聲估計和消除算法。首先,利用相鄰兩幀的幀頭符號中所包含的 PN(Pseudo Noise)序列,對幀體符號內的公共相位誤差進行粗估計;隨後,對幀體數據子載波進行標記,選取閤適的子載波集閤用于估計公共相位誤差和子載波間榦擾的精確結果。由此穫得相位譟聲頻域估計結果後,通過快速傅立葉變換(FFT,Fast Fourier Transform)得到時域估計結果併進行消除。和現有基于判決反饋的相位譟聲估計算法對比,本文所提算法的創新性在于採用瞭粗估計和精確估計結閤的方法,同時利用子載波標記的方法有效降低瞭由于錯誤判決導緻的誤碼擴散。倣真結果錶明在現有算法已經不能正常工作的情況下,本文所提算法還可以有效的抑製相位譟聲對繫統性能的影響。
상위조성회파배 OFDM(Orthogonal Frequency Division Multiplex)부호내빈역자재파적정교성,산생공공상위오차(CPE,Common Phase Error)화자재파간간우(ICI,Inter-Carrier Interference),대계통성능조성엄중영향。침대수자전시지면엄파전수표준연진방안(DTMB-A)적상위조성문제,본문제출료일충량보결합적상위조성고계화소제산법。수선,이용상린량정적정두부호중소포함적 PN(Pseudo Noise)서렬,대정체부호내적공공상위오차진행조고계;수후,대정체수거자재파진행표기,선취합괄적자재파집합용우고계공공상위오차화자재파간간우적정학결과。유차획득상위조성빈역고계결과후,통과쾌속부립협변환(FFT,Fast Fourier Transform)득도시역고계결과병진행소제。화현유기우판결반궤적상위조성고계산법대비,본문소제산법적창신성재우채용료조고계화정학고계결합적방법,동시이용자재파표기적방법유효강저료유우착오판결도치적오마확산。방진결과표명재현유산법이경불능정상공작적정황하,본문소제산법환가이유효적억제상위조성대계통성능적영향。
Phase noise destroys the orthogonality among subcarriers within one OFDM (Orthogonal Frequency Division Multiplex)block and causes common phase error (CPE)and inter-carrier interference (ICI),which significantly degrades the performance of OFDMsystem.To deal with the problem of phase noise in DTMB-A system,a two-step phase noise esti-mation method is proposed in this paper.Firstly,the rough estimation of CPE in frame body symbol is obtained by PN (Pseudo Noise)sequence in the frame header symbol;Secondly,the accurate estimation of CPE and ICI is obtained by marking the data subcarriers in frame body symbol and choosing the suitable subcarriers subset for decision feedback.The time domain estimation of phase noise is obtained by applying Fast Fourier Transform to the frequency domain estimation of phase noise,and then phase noise is corrected in time domain.Compared with the existing phase noise correction method, the innovation of proposed method is the combination of two-step estimations and the mitigation of error propagation problem cause by incorrect decision.Simulation results show that the proposed method can correct the phase noise effectively,even when the existing method fails.