IPC분류정보
국가/구분 |
United States(US) Patent
등록
|
국제특허분류(IPC7판) |
|
출원번호 |
US-0295310
(2006-11-30)
|
등록번호 |
US-8218978
(2012-07-10)
|
우선권정보 |
GB-0606745.8 (2006-04-04) |
국제출원번호 |
PCT/EP2006/069168
(2006-11-30)
|
§371/§102 date |
20090526
(20090526)
|
국제공개번호 |
WO2007/112790
(2007-10-11)
|
발명자
/ 주소 |
- Foggi, Tommaso
- Colavolpe, Giulio
- Forestieri, Enrico
- Prati, Giancarlo
|
출원인 / 주소 |
- Telefonaktiebolaget LM Ericsson (publ)
|
대리인 / 주소 |
Coats & Bennett, P.L.L.C.
|
인용정보 |
피인용 횟수 :
0 인용 특허 :
3 |
초록
▼
A method of and a receiver(20) for detection of a received signal in an optical fiber communication system using Viterbi algorithm methodology in which branch metrics are obtained using approximated expressions to calculate the branch metrics. Use of the expressions results in practically the same p
A method of and a receiver(20) for detection of a received signal in an optical fiber communication system using Viterbi algorithm methodology in which branch metrics are obtained using approximated expressions to calculate the branch metrics. Use of the expressions results in practically the same performance as a receiver based on exact metrics.
대표청구항
▼
1. A method of detecting a received signal in an optical fiber communication system using Viterbi algorithm methodology, the method comprising: amplifying the received signal by an optical amplifier;converting the received signal into an electrical signal by a photon detector;decoding the electrical
1. A method of detecting a received signal in an optical fiber communication system using Viterbi algorithm methodology, the method comprising: amplifying the received signal by an optical amplifier;converting the received signal into an electrical signal by a photon detector;decoding the electrical signal by a processor using a Viterbi algorithm comprising the following expression of Viterbi branch metrics: λ(ak,σk)≅2ZkSR(ak,σk)-SR(ak,σk)-N02(v-12)ln[SR(ak,σk)],wherein: σk is the state of the receiver at the kth bit interval;SR(ak, πk) is the substantially noise-free received sample at the kth bit interval;v is the number of degrees of freedom;ak is a possible value of the bit transmitted at the kth bit interval;Zk is the sample received at kth bit interval; andN0 is the power spectral density. 2. The method of claim 1 further comprising determining estimates of SR(ak,σk). 3. The method of claim 2 further comprising determining estimates of SR(ak,σk) for each pair (ak,σk). 4. The method of claim 1 further comprising obtaining samples at a rate of substantially one per bit interval. 5. The method of claim 1 further comprising determining values of SR(ak,σk) using a gradient algorithm as a cost function of the branch metrics. 6. The method of claim 1 further comprising determining values of SR(ak,σk) using mean square error methodology. 7. A method of detecting a signal received in an optical fiber communication system using the Viterbi algorithm, the method comprising: optically amplifying the received signal by an optical amplifier;converting the received signal into an electrical signal by a photon detector;decoding the electrical signal by a processor using a Viterbi algorithm comprising the following expression of Viterbi branch metrics: λ(ak,σk)≅∑i=01lnp(Zk,i|ak,σk);and obtaining multiple samples of the received signal per bit interval time; wherein: p(Zk,i|ak,σk) is the probability density function (PDF) of the received sample Zk,j;ak is the bit transmitted at the kth bit interval; andσk is the state of the receiver at the kth bit interval. 8. The method of claim 7 further comprising determining the probability density functions p(Zk,i|ak,σk) using the following expression: p(Zk,i|ak,σk)≅exp(-(Zk,i-SR,i)2N0)+(v-32)(Zk,i-1)4πN0SR,iv-1/2,wherein: N0 is the power spectral density; andSR,i(ak,σk) is the ith substantially noise-free received sample of the kth bit interval. 9. The method of claim 7 further comprising obtaining substantially two samples of the received signal per bit interval time. 10. The method of claim 8 further comprising determining values of SR(ak,σk) using a gradient algorithm as a cost function of the branch metrics. 11. The method of claim 8 further comprising determining values of SR,i(ak,σk) using mean square error methodology. 12. A receiver for an optical transmission system, the receiver comprising: an optical amplifier for amplifying a received optical signal;a photon detector for converting the received optical signal into an electrical signal; anda decoder configured to decode the received signal in an optical fiber communication system using a Viterbi algorithm methodology by:obtaining branch metrics using the following expression: λ(ak,σk)≅2ZkSR(ak,σk)-SR(ak,σk)-N02(v-12)ln[SR(ak,σk)],wherein: σk is the state of the receiver at the kth bit interval;SR(ak,σk) is the substantially noise-free received sample at the kth bit interval;v is the number of degrees of freedom;ak is a possible value of the bit transmitted at the kth bit interval;Zk is the sample received at kth bit interval; andN0 is the power spectral density. 13. A receiver for an optical transmission system, the receiver comprising: an optical amplifier for amplifying a received optical signal;a photon detector for converting the received optical signal into an electrical signal; anda decoder configured to detect a received signal in an optical fiber communication system using Viterbi algorithm methodology by:obtaining branch metrics using the expression: λ(ak,σk)≅∑i=01lnp(Zk,i|ak,σk);and obtaining multiple samples of the received signal per bit interval time; wherein: p(Zk,i|ak,σk) is the probability density function (PDF) of the received sample Zk,i;ak is the bit transmitted at the kh bit interval; andσk is the state of the receiver at the kth bit interval. 14. A non-transitory machine-readable medium comprising machine-readable instructions for decoding a received signal in an optical fiber communication system using Viterbi Algorithm by: determining a power spectral density (N0);computing a substantially noise-free received sample for each bit interval (SR(ak,σk)); anddecoding the received signal using a Maximum Likelihood Sequence Detection algorithm by using the following expression of Viterbi branch metrics: λ(ak,σk)≅2ZkSR(ak,σk)-SR(ak,σk)-N02(v-12)ln[SR(ak,σk)],wherein; σk is the state of the receiver at the kth bit interval;SR(ak,σk) is the substantially noise-free received sample at the kth bit interval;v is the number of degrees of freedom;ak is a possible value of the bit transmitted at the kth bit interval;Zk is the sample received at kth bit interval; andN0 is the power spectral density. 15. A non-transitory machine-readable medium comprising machine-readable, instructions for decoding a received signal in an optical fiber communication system using Viterbi algorithm methodology by: obtaining multiple samples of the received signal per bit interval time (Zk,i);calculating a probability density function p(Zk,i|ak,σk) for each of the multiple samples of the received signal; andobtaining branch metrics using the expression: λ(ak,σk)≅∑i=01lnp(Zk,i❘ak,σk);wherein:p(Zk,i|ak,σk) is the probability density function (PDF) of the received sample Zk,i;ak is the bit transmitted at the kth bit interval; andσk is the state of the receiver at the kth bit interval.
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