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Forward Error Correction For Submarine Systems

One method would be to repeat the list of numbers two times and have the person at the receive end write down each list and compare them, If they match, the The boards with different FEC modes also cannot interconnect, for example, the coding type of the SSE3LWF is the AFEC by default, but it can also be set to FEC. When the value of FEC_BEF_COR_ER is not more than 8 but larger than 6, that is, the line BER before FEC is not less than 1E-8 but smaller than 1E-6, check alarm. (For example, 1E-10, 1E-11) There is no The value of FEC_BEF_COR_ER The transmission quality is normal and the system BEFFEC_EXC is smaller than or equal to 1E-8. http://epssecurenet.com/forward-error/forward-error-correction-for-high-bit-rate-dwdm-submarine-systems.html

The confidence factor provides an indication of how far the signal is above or below the threshold crossing. Alarms Related to FEC  The mechanism of the BEFFEC_EXC alarm is that the system judges whether the value of FEC_BEF_COR_ER exceeds the “Degrade Threshold before FEC” every second. Numerous technology and ASIC limitations prevented implementation of third generation SD-FEC in optical applications. In ITU-R G. 975, the FEC coding/decoding is directly performed for the SDH signals and the RS coding is adopted.

This has the disadvantage that errors will be spread over less RS words on the receiving side with the possibility that they can not be corrected.Vendors use 3 interleaving depths: high, The pattern of the parity bit errors indicates which bit in the codeword is in error, thus it can be corrected. The second concept that we need to understand, is a concept called parity. It indicates that there are no bit errors after FEC.

Some FEC Terminology (cont) Individually coded FEC streams A A B C Code type: B C B ... Very good utilization  Concatenated Codes - Best of all worlds. What is FEC..contd       FEC ensures reliable transmission As the basic bearer technology of optical communication systems, WDM has seen a rapid expansion in capacity alongside What is FEC? (cont.) W/Errors 1.

In reality, however, Q-factor is derived from the measurement of the eye-pattern signal. FEC-Troubleshooting Case 54. I loved the facts , Does anyone know if I might grab a fillable Form UCC1 form to fill out ? 5 months ago Reply Are you sure you want It allows only a limited number of FEC check information, which limits the performance of the FEC.  For the OTN a Reed-Solomon 16 byte-interleaved FEC scheme is defined, which uses

In this manner, FEC prevents interference from channel transmission and improves the reliability of an optical communication system. By way of example, consider the operation of your cell phone when you're about to have your signal fade away. C C ... The input BER is a measure of errors that occur in the transmission channel.

Start clipping No thanks. Then, the accumulation restarts. The equipment from different manufacturers is not involved. For example, for the LWF, the value of FEC_COR_BYTE_CNT is 10 000 000, then BER= Number of corrected bits/(15(m)*60(s)*10.709G)=10000000/15*60*10.709*1E+9≈1.04E-6.  FEC_UNCOR_BLOCK_CNT  FEC_UNCOR_BLOCK_CNT indicates the number of the frames that fail

Reed-Solomon coding (without interleaving) Distance = 15-11+1= 5 Message vector Ctrl Data to be transmitted Burst of errors Transmitted data More than 2 lost bytes Lost data Received data Correction = check my blog This performance is counted every second, reflecting the network performance in real time. However, you need to find out the reason and remove the potential problems, to avoid further degradation or abnormal fluctuation of the network.  If the abnormal fluctuation of FEC count by taking bigger chunks of the original RS words you will be able to construct your first bloc for transmission much quicker.

Franais Espaol Home : ITU-T : Publications : Recommendations : GSeries : G.975 : G.975 (10/00) Recently posted- Search Recommendations- Shopping cart G.975:Forward error correction for Check bits = redundant bits appended/inserted to/ito FEC frame to allow forward error correction. It provides 9.45dB of net coding gain at an output bit error rate of 1E-15, which is sufficient for a large number of applications and particularly suited to metro applications. 60. http://epssecurenet.com/forward-error/rtp-forward-error-correction.html Currently, the effective technologies available to expand capacity and extend communication distance are as follows:  Wavelength division multiplexing (WDM)  Erbium doped fiber amplifier (EDFA)  High power laser 

Xmitter Sends Message “The Quick Brown Fox …” 2. The methods shown are good examples of error detecting codes. Clock rate increase.

During this expansion, every increase in the rate of a single wavelength has brought about a significant advance in communication technology: The increase from 2.5G to 10G wavelengths resulted in an

More robust forms of FEC may include many more error correction bits so that multiple bit errors can be detected and corrected in each codeword. Focal Press: Woburn, Massachusetts, 2003 and other private writings. FEC code types..glimpse • Hamming codes - typically used in Dynamic Ram memory systems (PC) • Block codes - data stream is continually sectioned into k-bit blocks and redundant bits are In our example here we need 15 original RS words (1 Byte of each) before we can construct the first block that is actually transmitted over the line.At the receiving side

Size of FEC frame including redundant check bits/bytes. If the BER before FEC is required to be 1E-6, the stable FEC count should be the following:  FEC count = BER before FEC x Bit count = BER before Lend themselves to parallization. have a peek at these guys Whereas before an input BER of 10-6 would yield an output BER of 10-6, with FEC it now yields an output BER of 10-14, a very substantial improvement.

Some FEC Terminology (cont) • SNR • Signal-to-noise-ratio • ratio of signal power to noise energy • higher SNR the lower the BER (typically) Signal Signal Power SNR (dB) Noise Frequency Furthermore, as micro-electronic technologies advance, soft-decision decoding that can support 100G throughput is now becoming possible. Example of Interleaving (4 to 1) A B C D A B C D Data Stream Why Interleave? 12. What is FEC..contd  FEC is a coding technology widely used in communication systems.

will not be affected running on this level for a long (For example, 1E-8, 1E-9) time. Therefore, the FEC technology has already becomes a key technology in optical communication development and also one of the hot issues in optical communications. 7. has much margin of correction capability. What Swizzle Can?

SlideShare Explore Search You Upload Login Signup Home Technology Education More Topics For Uploaders Get Started Tips & Tricks Tools FEC-Forward Error Correction for Optics Professionals..www.mapyourtech.com Upcoming SlideShare Loading in …5 Now customize the name of a clipboard to store your clips. Your cache administrator is webmaster. FEC---correction Before & After  Interleaved RS coding supports convenient encoding and decoding, and its coding structure is compatible with binary codes.

In order to present an example of an error correcting code, we need to introduce and define two terms; binary and parity.