## OFDM with Trailing Zeros versus OFDM with Cyclic Prefix: Links, Comparisons and Application to the HiperLAN/2 System (2000)

Venue: | In Proceedings of the Int. Conf. on Communications |

Citations: | 6 - 0 self |

### BibTeX

@INPROCEEDINGS{Courville00ofdmwith,

author = {Marc De Courville and Pierre Duhamel and Georgios Giannakis},

title = {OFDM with Trailing Zeros versus OFDM with Cyclic Prefix: Links, Comparisons and Application to the HiperLAN/2 System},

booktitle = {In Proceedings of the Int. Conf. on Communications},

year = {2000},

pages = {1049--1053}

}

### OpenURL

### Abstract

This paper proposes a simple equalizer for a recent multicarrier block transmission scheme which pads zeros (as opposed to a cyclic prefix) in each transmitted block. In the absence of high-power amplifier induced nonlinear effects, it is shown that the resulting scheme is simply the dual of the classical Cyclic Prefix OFDM transceiver. Comparison between the two systems that takes into account nonlinear distortions introduced by the clipper is also performed in the practical context of the wireless broadband 5GHz HiperLAN/2 system. Both the classical pilot-based as well as novel (semi-) blind subspace algorithms are applied for channel estimation. The advantage of subspace methods in lowering the variation of channel tracking is corroborated with simulations which verify practically accurate channel estimates along the bursts. 1.

### Citations

143 | Redundant filter bank precoders and equalizers Part II: Blind Channel Estimation, Synchronization, and direct equalization
- Scaglione, Giannakis, et al.
- 1999
(Show Context)
Citation Context ...re removed by dividing each subchannel output with a simple gain equal to the channel transfer function value at the corresponding subcarrier. Instead of inserting the CP, it was proposed recently in =-=[2]-=- to pad Trailing Zeroes (TZ) (a null signal) at the end of each IFFT modulated block. This new modulation, so termed TZ-OFDM, introduces the same amount of redundancy as CP-OFDM and thus results in th... |

42 |
CD3-OFDM: A novel demodulation scheme for fixed and mobile receivers
- Mignone, Morello
- 1996
(Show Context)
Citation Context ...nel estimate using: �s1¡�¢ Hi 1sri 0¡�¤ si 1¡¨� ri 1¡ © si for � 0 � i N 0¡¨� (3) ¥ 2 This method is the classical pilot-based estimation algorithm usually adopted by coherent modulation OFDM schemes =-=[8]-=-. Because only the entries m ¢ 12� 26� 40� 54 contain known (pilot) symbols in subsequent blocks ssk¡ k� 2, one can track adaptively the channel transfer function using a running average (over say B ¢... |

39 | Orthogonal transmultiplexers in communication: A review
- Akansu, Duhamel, et al.
- 1998
(Show Context)
Citation Context ...e frequency domain, classical multicarrier systems insert at the transmitter, after IFFT modulation, a time-domain redundant Cyclic Prefix (CP) of length larger than the FIR channel memory (see e.g., =-=[1]-=-). At the receiver end, CP is discarded to avoid interblock interference and each truncated block is FFT processed – an operation converting the frequency-selective channel output into parallel flat-f... |

38 |
Multirate digital signal processing
- Crochiere, Rabiner
- 1983
(Show Context)
Citation Context ...re ¢�¥ ˜h §¨§¨§ H0 HN 1© £ T FNh, where Hk denotes the channel’s trans¢ fer function on the kth subcarrier. This CP-OFDM property derives from the fast convolution algorithm based on the OLS approach =-=[6]-=- which enables a very simple equalization. The left part of Figure 4 presents the TZ precoder as proposed in [2] where the CP insertion is replaced by the transmission of Dstrailing zeroes at the tail... |

37 | On channel estimation in OFDM systems
- Beek, Edfors, et al.
- 1995
(Show Context)
Citation Context ...al pilot based method. This refinement consists in taking into account in the estimation process that channel in the frequency domain actually corresponds in the time domain to a FIR � N� of length 4 =-=[10]-=-. The channel estimation Mean Square Error (MSE) is only relevant on the U useful carriers since only these subbands will be equalized and is defined ¢ 1 as: ∑u��� � MSE U Hs�sH u¡�� 2 where � u¡ � is... |

26 |
A subspace based blind and semi-blind channel identification method for OFDM systems
- Muquet, Courville, et al.
- 1999
(Show Context)
Citation Context ...lored to the practical context of the HiperLAN/2 (HL2) standard. Additional comparisons are performed between two semi-blind subspace-based channel estimators developed for the CP and TZ precoders of =-=[4]-=- and [5], and both are also compared with the convenional pilot-based approach. To comply with the HL2 standard, some modifications of these algorithms are derived herein in order to account for the p... |

21 |
Redundant filterbank precoders and equalizers
- Scaglione, Giannakis, et al.
- 1999
(Show Context)
Citation Context ... the practical context of the HiperLAN/2 (HL2) standard. Additional comparisons are performed between two semi-blind subspace-based channel estimators developed for the CP and TZ precoders of [4] and =-=[5]-=-, and both are also compared with the convenional pilot-based approach. To comply with the HL2 standard, some modifications of these algorithms are derived herein in order to account for the presence ... |

13 |
Semi-blind second order identification of convolutive channels
- Gorokhov, Loubaton
- 1997
(Show Context)
Citation Context ...rion, whose solution is given by �sh ¡ £ Q ¢ pil 1 FpilH � Hpil where Qpil ∑ ¢ D £ 1 � � � � H 0 ¤ i i� i FpilH Fpil , is very close to the semiblind criterion already proposed for another context in =-=[9]-=-. The difference in our case is that the training symbols cannot provide alone a channel estimation. As illustrated in the simulations, the resulting semi-blind algorithm combining all the previous de... |

5 |
Reducing the Peak to Average Power Ratio of OFDM
- Nee, Wild
- 1998
(Show Context)
Citation Context ...he same global transfer function and are expected to perform similarly. Because HPA-NL have to be taken into account in practice, we consider the Peak to Average Power Ratio (PAPR) as figure of merit =-=[3]-=-, and compare TZ-OFDM-OLA with CP-OFDM both analytically and with realistic simulations tailored to the practical context of the HiperLAN/2 (HL2) standard. Additional comparisons are performed between... |

2 |
Giannakis, “Modulo pre-equalization of nonlinear communication channels
- Kambanellas, B
- 1999
(Show Context)
Citation Context ...ortions [3] which destroy orthogonality between the carriers and deteriorate the OFDM system performance by introducing intercarrier interference. Thus, even if correction methods have been developed =-=[7]-=-, it is shown below that, for a given clipping ratio (number of clipped symbols divided by the total number of transmitted symbols), the mean transmitted power by TZ-OFDM is smaller compared to CP-OFD... |

1 |
Complexity constrained channel estimation for OFDM based transmission over fast fading channels
- Speth, Meyr
- 1999
(Show Context)
Citation Context ...es corresponding to the U useful carriers. Moreover, in order to better quantify the impact of the channel estimation on the system overall performance, we use the following “effective SNR” criterion =-=[11]-=- defined as: SNReff ¢ � 10 log10 � 10£ SNR� 10 ¤ 10 MSE� 10� (9) This criterion can indeed be interpreted as the comprehensive SNR observed at the receiver by the Viterbi decoder. In fact, the Viterbi... |