soft decisions: what decision function to use?
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From: gct on 6 Jul 2010 14:16 When generating soft decisions from symbols, what's the best decision function to use? Is some linear approximation of a sigmoid suitable? What effect does the decision function have on the performance of the system?
From: Clay on 6 Jul 2010 14:25 On Jul 6, 2:16 pm, "gct" <smcallis(a)n_o_s_p_a_m.gmail.com> wrote: > When generating soft decisions from symbols, what's the best decision > function to use? Is some linear approximation of a sigmoid suitable? What > effect does the decision function have on the performance of the system? I think you need to be more specific in your question. I'm not sure if "sigmoid" here refers to the lower part of one's colon or to a general class of mathematical functions or to a specific sigmoid function such as the logistic.
From: gct on 6 Jul 2010 14:32 >On Jul 6, 2:16=A0pm, "gct" <smcallis(a)n_o_s_p_a_m.gmail.com> wrote: >> When generating soft decisions from symbols, what's the best decision >> function to use? =A0Is some linear approximation of a sigmoid suitable? = >=A0What >> effect does the decision function have on the performance of the system? > >I think you need to be more specific in your question. I'm not sure if >"sigmoid" here refers to the lower part of one's colon or to a general >class of mathematical functions or to a specific sigmoid function such >as the logistic. > I was referring to something of the general form 1/(1+e^-t)
From: Vladimir Vassilevsky on 6 Jul 2010 14:34 gct wrote: > When generating soft decisions from symbols, what's the best decision > function to use? By definition, soft decision = likelihood of this symbol. The particular likelihood function depends on the signal and the channel. > Is some linear approximation of a sigmoid suitable? It depends. > What effect does the decision function have on the performance of the system? Yes, it does. Vladimir Vassilevsky DSP and Mixed Signal Design Consultant http://www.abvolt.com
From: gct on 6 Jul 2010 16:07
>By definition, soft decision = likelihood of this symbol. The particular >likelihood function depends on the signal and the channel. > >Vladimir Vassilevsky >DSP and Mixed Signal Design Consultant >http://www.abvolt.com > How about a simple BPSK signal over an AGWN channel? |