Hi, Anyone is aware of state search algorithms in MLSE (maximum likelihood sequence equalization) other than the Viterbi? Thanks

# New algorithms in MLSE?

Started by ●October 26, 2013

Reply by ●October 27, 20132013-10-27

On Sat, 26 Oct 2013 14:18:09 -0700 (PDT), Verictor <stehuang@gmail.com> wrote:>Hi, > >Anyone is aware of state search algorithms in MLSE (maximum likelihood sequence equalization) other than the Viterbi? > >ThanksSequential decoder? Can I ask why you think you need MLSE? Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com

Reply by ●October 29, 20132013-10-29

On Sunday, October 27, 2013 1:02:07 AM UTC-7, Eric Jacobsen wrote:> On Sat, 26 Oct 2013 14:18:09 -0700 (PDT), Verictor > > <stehuang@gmail.com> wrote: > > > > >Hi, > > > > > >Anyone is aware of state search algorithms in MLSE (maximum likelihood sequence equalization) other than the Viterbi? > > > > > >Thanks > > > > Sequential decoder? > > > > Can I ask why you think you need MLSE? > > > > > > Eric Jacobsen > > Anchor Hill Communications > > http://www.anchorhill.comFor some reason, my Group didn't get updated to see new posts. Sequential decoder is used on convolutional codes, as far as I know. Can it also be used on non-coded communication? In particular, combined equalization and maximum likelihood state estimate? I was referring to channel estimate along with incoming sequence detection. There may be ways to incorporate CIR estimate in the sequential decoder (or someone had done that already but I don't know). I was asking to see if someone knows new techniques to minimize the search. Why need MLSE? I think a sequence base, not symbol-by-symbol, approach is optimal as intuitively, we have more degree of information. Thanks

Reply by ●October 29, 20132013-10-29

On Tue, 29 Oct 2013 10:31:44 -0700 (PDT), Verictor <stehuang@gmail.com> wrote:>On Sunday, October 27, 2013 1:02:07 AM UTC-7, Eric Jacobsen wrote: >> On Sat, 26 Oct 2013 14:18:09 -0700 (PDT), Verictor >>=20 >> <stehuang@gmail.com> wrote: >>=20 >>=20 >>=20 >> >Hi, >>=20 >> > >>=20 >> >Anyone is aware of state search algorithms in MLSE (maximum likelihood s= >equence equalization) other than the Viterbi? >>=20 >> > >>=20 >> >Thanks >>=20 >>=20 >>=20 >> Sequential decoder? >>=20 >>=20 >>=20 >> Can I ask why you think you need MLSE? >>=20 >>=20 >>=20 >>=20 >>=20 >> Eric Jacobsen >>=20 >> Anchor Hill Communications >>=20 >> http://www.anchorhill.com > >For some reason, my Group didn't get updated to see new posts.=20 > >Sequential decoder is used on convolutional codes, as far as I know. Can it= > also be used on non-coded communication? In particular, combined equalizat= >ion and maximum likelihood state estimate?It's possible, but sequential decoding is used primarily when a long constraint length can be tolerated in favor of better performance. Modulation-based trellis patterns tend to be short, which favors the Viterbi algorithm.> I was referring to channel estim= >ate along with incoming sequence detection.Soft-input sequential decoders exist.> There may be ways to incorporat= >e CIR estimate in the sequential decoder (or someone had done that already = >but I don't know). I was asking to see if someone knows new techniques to m= >inimize the search.=20 > >Why need MLSE? I think a sequence base, not symbol-by-symbol, approach is o= >ptimal as intuitively, we have more degree of information.=20 > >ThanksEric Jacobsen Anchor Hill Communications http://www.anchorhill.com

Reply by ●October 30, 20132013-10-30

On Tuesday, October 29, 2013 2:33:13 PM UTC-4, Eric Jacobsen wrote:> On Tue, 29 Oct 2013 10:31:44 -0700 (PDT), Verictor > > <stehuang@gmail.com> wrote: > > > > >On Sunday, October 27, 2013 1:02:07 AM UTC-7, Eric Jacobsen wrote: > > >> On Sat, 26 Oct 2013 14:18:09 -0700 (PDT), Verictor > > >>=20 > > >> <stehuang@gmail.com> wrote: > > >>=20 > > >>=20 > > >>=20 > > >> >Hi, > > >>=20 > > >> > > > >>=20 > > >> >Anyone is aware of state search algorithms in MLSE (maximum likelihood s= > > >equence equalization) other than the Viterbi? > > >>=20 > > >> > > > >>=20 > > >> >Thanks > > >>=20 > > >>=20 > > >>=20 > > >> Sequential decoder? > > >>=20 > > >>=20 > > >>=20 > > >> Can I ask why you think you need MLSE? > > >>=20 > > >>=20 > > >>=20 > > >>=20 > > >>=20 > > >> Eric Jacobsen > > >>=20 > > >> Anchor Hill Communications > > >>=20 > > >> http://www.anchorhill.com > > > > > >For some reason, my Group didn't get updated to see new posts.=20 > > > > > >Sequential decoder is used on convolutional codes, as far as I know. Can it= > > > also be used on non-coded communication? In particular, combined equalizat= > > >ion and maximum likelihood state estimate? > > > > It's possible, but sequential decoding is used primarily when a long > > constraint length can be tolerated in favor of better performance. > > Modulation-based trellis patterns tend to be short, which favors the > > Viterbi algorithm. > > > > > I was referring to channel estim= > > >ate along with incoming sequence detection. > > > > Soft-input sequential decoders exist. >I've never actually implemented a SISO sequential decoders. Dosn't soft sequential decoder become more complex so that it loss its advantage of simpler implementation complexity? I think some texts say sequential decoder is usually hard decoder. There are second opinions on this?> > > > There may be ways to incorporat= > > >e CIR estimate in the sequential decoder (or someone had done that already = > > >but I don't know). I was asking to see if someone knows new techniques to m= > > >inimize the search.=20 > > > > > >Why need MLSE? I think a sequence base, not symbol-by-symbol, approach is o= > > >ptimal as intuitively, we have more degree of information.=20 > > > > > >Thanks > > > > > > > > Eric Jacobsen > > Anchor Hill Communications > > http://www.anchorhill.com

Reply by ●October 30, 20132013-10-30

On Tue, 29 Oct 2013 21:47:54 -0700 (PDT), Verictor <stehuang@gmail.com> wrote:>On Tuesday, October 29, 2013 2:33:13 PM UTC-4, Eric Jacobsen wrote: >> On Tue, 29 Oct 2013 10:31:44 -0700 (PDT), Verictor >>=20 >> <stehuang@gmail.com> wrote: >>=20 >>=20 >>=20 >> >On Sunday, October 27, 2013 1:02:07 AM UTC-7, Eric Jacobsen wrote: >>=20 >> >> On Sat, 26 Oct 2013 14:18:09 -0700 (PDT), Verictor >>=20 >> >>=3D20 >>=20 >> >> <stehuang@gmail.com> wrote: >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >> >Hi, >>=20 >> >>=3D20 >>=20 >> >> > >>=20 >> >>=3D20 >>=20 >> >> >Anyone is aware of state search algorithms in MLSE (maximum likelihoo= >d s=3D >>=20 >> >equence equalization) other than the Viterbi? >>=20 >> >>=3D20 >>=20 >> >> > >>=20 >> >>=3D20 >>=20 >> >> >Thanks >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >> Sequential decoder? >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >> Can I ask why you think you need MLSE? >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >>=3D20 >>=20 >> >> Eric Jacobsen >>=20 >> >>=3D20 >>=20 >> >> Anchor Hill Communications >>=20 >> >>=3D20 >>=20 >> >> http://www.anchorhill.com >>=20 >> > >>=20 >> >For some reason, my Group didn't get updated to see new posts.=3D20 >>=20 >> > >>=20 >> >Sequential decoder is used on convolutional codes, as far as I know. Can= > it=3D >>=20 >> > also be used on non-coded communication? In particular, combined equali= >zat=3D >>=20 >> >ion and maximum likelihood state estimate? >>=20 >>=20 >>=20 >> It's possible, but sequential decoding is used primarily when a long >>=20 >> constraint length can be tolerated in favor of better performance. >>=20 >> Modulation-based trellis patterns tend to be short, which favors the >>=20 >> Viterbi algorithm. >>=20 >>=20 >>=20 >> > I was referring to channel estim=3D >>=20 >> >ate along with incoming sequence detection. >>=20 >>=20 >>=20 >> Soft-input sequential decoders exist. >>=20 > >I've never actually implemented a SISO sequential decoders. Dosn't soft seq= >uential decoder become more complex so that it loss its advantage of simple= >r implementation complexity? I think some texts say sequential decoder is u= >sually hard decoder. There are second opinions on this?Soft-input sequential decoders have been around a long time and are generally of lower complexity than (or comparable complexity to, depending on constraint lengths) a typical soft-input Viterbi decoder. But I was mostly thinking of detection or decoding rather than an MLSE Equalizer (brain fart on my part, as you did say equalizer). A MAP decoder (aka APP decoder) is not an MLSE, but it can be used for equalization in the same manner as a Viterbi algorithm, or joint channel estimation and equalization. I doubt a sequential decoder would be desirable for channel estimation or equalization unless the channel delay spread covered a large number of symbols, i.e., the equalizer was hugely complex. So, probably not practical.>>=20 >>=20 >> > There may be ways to incorporat=3D >>=20 >> >e CIR estimate in the sequential decoder (or someone had done that alrea= >dy =3D >>=20 >> >but I don't know). I was asking to see if someone knows new techniques t= >o m=3D >>=20 >> >inimize the search.=3D20 >>=20 >> > >>=20 >> >Why need MLSE? I think a sequence base, not symbol-by-symbol, approach i= >s o=3D >>=20 >> >ptimal as intuitively, we have more degree of information.=3D20 >>=20 >> > >>=20 >> >Thanks >>=20 >>=20 >>=20 >>=20 >>=20 >>=20 >>=20 >> Eric Jacobsen >>=20 >> Anchor Hill Communications >>=20 >> http://www.anchorhill.com >Eric Jacobsen Anchor Hill Communications http://www.anchorhill.com

Reply by ●October 30, 20132013-10-30

On Tuesday, October 29, 2013 10:21:33 PM UTC-7, Eric Jacobsen wrote:> On Tue, 29 Oct 2013 21:47:54 -0700 (PDT), Verictor > > <stehuang@gmail.com> wrote: > > > > >On Tuesday, October 29, 2013 2:33:13 PM UTC-4, Eric Jacobsen wrote: > > >> On Tue, 29 Oct 2013 10:31:44 -0700 (PDT), Verictor > > >>=20 > > >> <stehuang@gmail.com> wrote: > > >>=20 > > >>=20 > > >>=20 > > >> >On Sunday, October 27, 2013 1:02:07 AM UTC-7, Eric Jacobsen wrote: > > >>=20 > > >> >> On Sat, 26 Oct 2013 14:18:09 -0700 (PDT), Verictor > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> <stehuang@gmail.com> wrote: > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> >Hi, > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> > > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> >Anyone is aware of state search algorithms in MLSE (maximum likelihoo= > > >d s=3D > > >>=20 > > >> >equence equalization) other than the Viterbi? > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> > > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> >Thanks > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> Sequential decoder? > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> Can I ask why you think you need MLSE? > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> Eric Jacobsen > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> Anchor Hill Communications > > >>=20 > > >> >>=3D20 > > >>=20 > > >> >> http://www.anchorhill.com > > >>=20 > > >> > > > >>=20 > > >> >For some reason, my Group didn't get updated to see new posts.=3D20 > > >>=20 > > >> > > > >>=20 > > >> >Sequential decoder is used on convolutional codes, as far as I know. Can= > > > it=3D > > >>=20 > > >> > also be used on non-coded communication? In particular, combined equali= > > >zat=3D > > >>=20 > > >> >ion and maximum likelihood state estimate? > > >>=20 > > >>=20 > > >>=20 > > >> It's possible, but sequential decoding is used primarily when a long > > >>=20 > > >> constraint length can be tolerated in favor of better performance. > > >>=20 > > >> Modulation-based trellis patterns tend to be short, which favors the > > >>=20 > > >> Viterbi algorithm. > > >>=20 > > >>=20 > > >>=20 > > >> > I was referring to channel estim=3D > > >>=20 > > >> >ate along with incoming sequence detection. > > >>=20 > > >>=20 > > >>=20 > > >> Soft-input sequential decoders exist. > > >>=20 > > > > > >I've never actually implemented a SISO sequential decoders. Dosn't soft seq= > > >uential decoder become more complex so that it loss its advantage of simple= > > >r implementation complexity? I think some texts say sequential decoder is u= > > >sually hard decoder. There are second opinions on this? > > > > Soft-input sequential decoders have been around a long time and are > > generally of lower complexity than (or comparable complexity to, > > depending on constraint lengths) a typical soft-input Viterbi decoder. > > > > > > But I was mostly thinking of detection or decoding rather than an MLSE > > Equalizer (brain fart on my part, as you did say equalizer). A MAP > > decoder (aka APP decoder) is not an MLSE, but it can be used for > > equalization in the same manner as a Viterbi algorithm, or joint > > channel estimation and equalization. > > > > I doubt a sequential decoder would be desirable for channel estimation > > or equalization unless the channel delay spread covered a large number > > of symbols, i.e., the equalizer was hugely complex. So, probably not > > practical. >That is a candid suggestion. When I asked, I was thinking other ways to do VA. Thanks anyway.> > >>=20 > > >>=20 > > >> > There may be ways to incorporat=3D > > >>=20 > > >> >e CIR estimate in the sequential decoder (or someone had done that alrea= > > >dy =3D > > >>=20 > > >> >but I don't know). I was asking to see if someone knows new techniques t= > > >o m=3D > > >>=20 > > >> >inimize the search.=3D20 > > >>=20 > > >> > > > >>=20 > > >> >Why need MLSE? I think a sequence base, not symbol-by-symbol, approach i= > > >s o=3D > > >>=20 > > >> >ptimal as intuitively, we have more degree of information.=3D20 > > >>=20 > > >> > > > >>=20 > > >> >Thanks > > >>=20 > > >>=20 > > >>=20 > > >>=20 > > >>=20 > > >>=20 > > >>=20 > > >> Eric Jacobsen > > >>=20 > > >> Anchor Hill Communications > > >>=20 > > >> http://www.anchorhill.com > > > > > > > Eric Jacobsen > > Anchor Hill Communications > > http://www.anchorhill.com