OFDM Carrier Synchronization Based on Time-Domain Channel Estimates

Zhou, Hao; Malipatil, Amaresh; Huang, Yih-Fang

doi:10.1109/twc.2008.060765

Cited by 19 publications

(4 citation statements)

References 19 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In (23), the first arrival path component of the signal produces a circular shift of z/2+m with respect to the original sequence. Since the CP length is greater than the channel length, the correlation results for different path components can be sharply peaked by correlating the frequency domain sequence of the received preamble with the original sequence by a reverse circular shift of length CP.…”

Section: E Signal First Arrival Path Detectionmentioning

confidence: 99%

“…Large deviations in timing-frequency estimation can lead to dramatic degradation of the system performance. Therefore, researchers have continuously explored and improved timing offset estimation methods [13][14][15][16][17][18][19][20][21] and carrier frequency offset (CFO) estimation methods [15,16,[22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

“…Carrier frequency offset estimation methods are used to compensate for frequency errors due to channel Doppler expansion and sampling errors between receiver transmitters. The presence of offset affects the orthogonality between subcarriers leading to Inter-Carrier Interference (ICI), which is usually estimated in the time domain [22][23][24] and the frequency domain [25,26]. As the time domain method, Morelli achieved CFO estimation by having J identical parts of the preamble, but the estimation range is small [22].…”

Section: Introductionmentioning

confidence: 99%

“…As the time domain method, Morelli achieved CFO estimation by having J identical parts of the preamble, but the estimation range is small [22]. Hao combined time domain channel estimation and ML methods for CFO estimation, but this method requires knowledge of the frequency response of the channel and has poor real-time performance [23]. Gui proposed a 3-stage CFO estimator by inserting PN sequences between OFDM symbols to achieve better estimation, but the extra redundancy makes the transmission efficiency of the system low [24].…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

A Robust Time-Frequency Synchronization Method for Underwater Acoustic OFDM Communication Systems

Yang,

Wang,

Peng

et al. 2024

IEEE Access

View full text Add to dashboard Cite

The strong multipath and long delay extensions can lead to large errors in the timing offset estimation and carrier frequency offset estimation of the Orthogonal Frequency Division Multiplexing (OFDM) underwater communication system, resulting in significant performance degradation. Therefore, this paper proposes a robust time-frequency synchronization method for OFDM systems. First, a new preamble based on Constant Amplitude Zero Autocorrelation (CAZAC) sequence is designed, and a new signal timing offset estimation method is developed based on the time domain characteristics of the preamble. Secondly, a two-stage frequency offset estimation (CFO) method is designed in the time domain followed by the frequency domain, which achieves a wide range of high-accuracy frequency offset estimation. Finally, an adaptive threshold signal first-arrival path detection method is proposed to achieve reliable detection of the position of the signal first-arrival path under complex multipath channels. The simulation, pool, and lake experiment results are provided to verify the reliability and effectiveness of this method. Compared with the traditional methods, the proposed method can more accurately obtain the signal timing position and estimate the CFO in complex multipath channels, and at the same time greatly expand the estimation range of the CFO.INDEX TERMS Carrier frequency offset, time synchronization, OFDM, underwater acoustic communications.

show abstract

Section: E Signal First Arrival Path Detectionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A Robust Time-Frequency Synchronization Method for Underwater Acoustic OFDM Communication Systems

Yang,

Wang,

Peng

et al. 2024

IEEE Access

View full text Add to dashboard Cite

show abstract

References

2012

Cognitive Radio Communications and Networking

View full text Add to dashboard Cite

Joint carrier frequency offset and channel estimation for OFDM systems with two receive antennas

Al-Bayati

Smadi

Saraereh

et al. 2015

Int J Communication

View full text Add to dashboard Cite

Carrier frequency offset (CFO) in OFDM systems results in loss of channel orthogonality and hence degrades the system's performance. In this paper, we propose a new method for joint CFO/channel estimation for OFDM systems with two receive antennas. Our method avoids the complexity of full search methods in one or two dimensions. Using one training OFDM symbol and utilizing the knowledge of the structure of the inter-channel interference that results from CFO, we develop a two-stage estimation procedure. The first stage derives an initial CFO/channel estimate based on a one shot minimization step. The second stage refines this joint estimate by conducting a small CFO search in the vicinity of the initial estimate. This procedure provides CFO estimates over a full range of ÀN/2-N/2, (N: number of subcarriers), as well as the channel estimates. Computer simulations show an excellent performance that is very close to the Cramer-Rao lower bound and superior to some existing methods. The effect of antenna correlation on performance is also investigated through computer simulations, showing small performance degradation even at medium correlation coefficients (0.3-0.6).

show abstract

OFDM Carrier Synchronization Based on Time-Domain Channel Estimates

Cited by 19 publications

References 19 publications

A Robust Time-Frequency Synchronization Method for Underwater Acoustic OFDM Communication Systems

A Robust Time-Frequency Synchronization Method for Underwater Acoustic OFDM Communication Systems

References

Joint carrier frequency offset and channel estimation for OFDM systems with two receive antennas

Contact Info

Product

Resources

About