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An OFDM Receiver with Frequency Domain Diversity Combined Impulsive Noise Canceller for Underwater Network.

Saotome R, Hai TM, Matsuda Y, Suzuki T, Wada T - ScientificWorldJournal (2015)

Bottom Line: The OFDM receiver utilizes 20-28 KHz ultrasonic channel and subcarrier spacing of 46.875 Hz (MODE3) and 93.750 Hz (MODE2) OFDM modulations.In addition, the paper shows Impulsive Noise distribution data measured at a fishing port in Okinawa and at a barge in Shizuoka prefectures and then proposed diversity OFDM transceivers architecture and experimental results are described.By the proposed Impulsive Noise Canceller, frame bit error rate has been decreased by 20-30%.

View Article: PubMed Central - PubMed

Affiliation: Department of Information Engineering, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan.

ABSTRACT
In order to explore marine natural resources using remote robotic sensor or to enable rapid information exchange between ROV (remotely operated vehicles), AUV (autonomous underwater vehicle), divers, and ships, ultrasonic underwater communication systems are used. However, if the communication system is applied to rich living creature marine environment such as shallow sea, it suffers from generated Impulsive Noise so-called Shrimp Noise, which is randomly generated in time domain and seriously degrades communication performance in underwater acoustic network. With the purpose of supporting high performance underwater communication, a robust digital communication method for Impulsive Noise environments is necessary. In this paper, we propose OFDM ultrasonic communication system with diversity receiver. The main feature of the receiver is a newly proposed Frequency Domain Diversity Combined Impulsive Noise Canceller. The OFDM receiver utilizes 20-28 KHz ultrasonic channel and subcarrier spacing of 46.875 Hz (MODE3) and 93.750 Hz (MODE2) OFDM modulations. In addition, the paper shows Impulsive Noise distribution data measured at a fishing port in Okinawa and at a barge in Shizuoka prefectures and then proposed diversity OFDM transceivers architecture and experimental results are described. By the proposed Impulsive Noise Canceller, frame bit error rate has been decreased by 20-30%.

No MeSH data available.


Time and Frequency Domain Impulsive Noise Canceller.
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Related In: Results  -  Collection


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fig7: Time and Frequency Domain Impulsive Noise Canceller.

Mentions: Because of the presence of Impulsive Noise so-called Shrimp Noise, time and frequency domain Impulsive Noise Cancelling (time-IMP and freq.-IMP) methods [4, 5] are employed and further combined with carrier diversity combiner. The block diagram of time-IMP (circle-A in Figure 6) is shown in Figure 7(a). It detects Impulsive Noise samples in time domain and then removes the Impulsive Noise samples according to (2)yn=rnif  rn2≤α·Pavg0otherwise.Here r(n) is nth time sample of received signal after preamplifier, Pavg is the average power of an OFDM symbol, and α is threshold parameter. Obviously, if the power of input signal r(n) exceeds the threshold of  α · Pavg, the signal is replaced by zero. This method is called “blanking” [10, 11]. In order to determine the threshold parameter  α, cut and try experimentation was applied and finally α = 20 is determined. The system performance is not so sensitive to the parameter.


An OFDM Receiver with Frequency Domain Diversity Combined Impulsive Noise Canceller for Underwater Network.

Saotome R, Hai TM, Matsuda Y, Suzuki T, Wada T - ScientificWorldJournal (2015)

Time and Frequency Domain Impulsive Noise Canceller.
© Copyright Policy - open-access
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4553320&req=5

fig7: Time and Frequency Domain Impulsive Noise Canceller.
Mentions: Because of the presence of Impulsive Noise so-called Shrimp Noise, time and frequency domain Impulsive Noise Cancelling (time-IMP and freq.-IMP) methods [4, 5] are employed and further combined with carrier diversity combiner. The block diagram of time-IMP (circle-A in Figure 6) is shown in Figure 7(a). It detects Impulsive Noise samples in time domain and then removes the Impulsive Noise samples according to (2)yn=rnif  rn2≤α·Pavg0otherwise.Here r(n) is nth time sample of received signal after preamplifier, Pavg is the average power of an OFDM symbol, and α is threshold parameter. Obviously, if the power of input signal r(n) exceeds the threshold of  α · Pavg, the signal is replaced by zero. This method is called “blanking” [10, 11]. In order to determine the threshold parameter  α, cut and try experimentation was applied and finally α = 20 is determined. The system performance is not so sensitive to the parameter.

Bottom Line: The OFDM receiver utilizes 20-28 KHz ultrasonic channel and subcarrier spacing of 46.875 Hz (MODE3) and 93.750 Hz (MODE2) OFDM modulations.In addition, the paper shows Impulsive Noise distribution data measured at a fishing port in Okinawa and at a barge in Shizuoka prefectures and then proposed diversity OFDM transceivers architecture and experimental results are described.By the proposed Impulsive Noise Canceller, frame bit error rate has been decreased by 20-30%.

View Article: PubMed Central - PubMed

Affiliation: Department of Information Engineering, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan.

ABSTRACT
In order to explore marine natural resources using remote robotic sensor or to enable rapid information exchange between ROV (remotely operated vehicles), AUV (autonomous underwater vehicle), divers, and ships, ultrasonic underwater communication systems are used. However, if the communication system is applied to rich living creature marine environment such as shallow sea, it suffers from generated Impulsive Noise so-called Shrimp Noise, which is randomly generated in time domain and seriously degrades communication performance in underwater acoustic network. With the purpose of supporting high performance underwater communication, a robust digital communication method for Impulsive Noise environments is necessary. In this paper, we propose OFDM ultrasonic communication system with diversity receiver. The main feature of the receiver is a newly proposed Frequency Domain Diversity Combined Impulsive Noise Canceller. The OFDM receiver utilizes 20-28 KHz ultrasonic channel and subcarrier spacing of 46.875 Hz (MODE3) and 93.750 Hz (MODE2) OFDM modulations. In addition, the paper shows Impulsive Noise distribution data measured at a fishing port in Okinawa and at a barge in Shizuoka prefectures and then proposed diversity OFDM transceivers architecture and experimental results are described. By the proposed Impulsive Noise Canceller, frame bit error rate has been decreased by 20-30%.

No MeSH data available.