A communication system (Markov chain)

Win_odd Dhamnekar

Junior Member
Joined
Aug 14, 2018
Messages
207
A Communications System) Consider a communications system that transmits the digits 0 and 1. Each digit transmitted must pass through several stages, at each of which there is a probability p that the digit entered will be unchanged when it leaves. Letting [imath]X_n[/imath] denote the digit entering the nth stage, then [imath]\{X_n, n = 0,1 , . . .\}[/imath] is a two-state Markov chain having transition probability matrix[math]P=\begin{Vmatrix} p & 1-p \\ 1-p & p \end{Vmatrix}[/math]
Now, how to show by mathematical indiction, that [math]P^{(n)} = \begin{Vmatrix} \frac12 + \frac12 (2p-1)^n & \frac12 -\frac12(2p-1)^n \\ \frac12 - \frac12 (2p-1)^n & \frac12 + \frac12(2p-1)^n \end {Vmatrix}[/math]
How to answer this question?
 
A Communications System) Consider a communications system that transmits the digits 0 and 1. Each digit transmitted must pass through several stages, at each of which there is a probability p that the digit entered will be unchanged when it leaves. Letting [imath]X_n[/imath] denote the digit entering the nth stage, then [imath]\{X_n, n = 0,1 , . . .\}[/imath] is a two-state Markov chain having transition probability matrix[math]P=\begin{Vmatrix} p & 1-p \\ 1-p & p \end{Vmatrix}[/math]
Now, how to show by mathematical indiction, that [math]P^{(n)} = \begin{Vmatrix} \frac12 + \frac12 (2p-1)^n & \frac12 -\frac12(2p-1)^n \\ \frac12 - \frac12 (2p-1)^n & \frac12 + \frac12(2p-1)^n \end {Vmatrix}[/math]
How to answer this question?
It is really disheartening that after 150 posts (in about 4 years}, we have to still remind you:

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:


Please share your work/thoughts about this problem
 
A Communications System) Consider a communications system that transmits the digits 0 and 1. Each digit transmitted must pass through several stages, at each of which there is a probability p that the digit entered will be unchanged when it leaves. Letting [imath]X_n[/imath] denote the digit entering the nth stage, then [imath]\{X_n, n = 0,1 , . . .\}[/imath] is a two-state Markov chain having transition probability matrix[math]P=\begin{Vmatrix} p & 1-p \\ 1-p & p \end{Vmatrix}[/math]
Now, how to show by mathematical indiction, that [math]P^{(n)} = \begin{Vmatrix} \frac12 + \frac12 (2p-1)^n & \frac12 -\frac12(2p-1)^n \\ \frac12 - \frac12 (2p-1)^n & \frac12 + \frac12(2p-1)^n \end {Vmatrix}[/math]
How to answer this question?
First of all, [imath]n[/imath] should exclude 0, i.e. [imath]n \in \{1,2,...\}[/imath]

Test the base case [imath](n=1)[/imath]. Is it true?
If the base is true, then assume [imath]n=k[/imath] is true and show that for [imath]n = k+1[/imath]:

[imath]P^{k+1}=P^k\times P^1 = \begin{Vmatrix} \frac12 + \frac12 (2p-1)^{k+1} & \frac12 -\frac12(2p-1)^{k+1} \\ \frac12 - \frac12 (2p-1)^{k+1} & \frac12 + \frac12(2p-1)^{k+1} \end {Vmatrix}[/imath]
 
It is really disheartening that after 150 posts (in about 4 years}, we have to still remind you:

Please show us what you have tried and exactly where you are stuck.

Please follow the rules of posting in this forum, as enunciated at:


Please share your work/thoughts about this problem
Sorry for ignoring to follow the rules of posting.

[math]P^{(2)} = \begin{Vmatrix} 2p^2 -2p +1 & -(2p^2-2p)\\- (2p^2-2p) & 2p^2 -2p +1 \end{Vmatrix} = \begin{Vmatrix} \frac12 + \frac12(2p-1)^2 & \frac12 - \frac12(2p-1)^2 \\ \frac12 - \frac12(2p-1)^2 & \frac12 + \frac12(2p-1)^2 \end{Vmatrix}[/math]
Hence,
[math]P^{(n)} =\begin{Vmatrix} \frac12 + \frac12 (2p-1)^n & \frac12 -\frac12(2p-1)^n \\ \frac12 -\frac12(2p-1)^n & \frac12 +\frac12(2p-1)^n \end{Vmatrix}[/math]
I solved this problem myself. Thanks to advise me to try to answer this question myself. It was easy to answer this question.
 
Sorry for ignoring to follow the rules of posting.

[math]P^{(2)} = \begin{Vmatrix} 2p^2 -2p +1 & -(2p^2-2p)\\- (2p^2-2p) & 2p^2 -2p +1 \end{Vmatrix} = \begin{Vmatrix} \frac12 + \frac12(2p-1)^2 & \frac12 - \frac12(2p-1)^2 \\ \frac12 - \frac12(2p-1)^2 & \frac12 + \frac12(2p-1)^2 \end{Vmatrix}[/math]
Hence,
[math]P^{(n)} =\begin{Vmatrix} \frac12 + \frac12 (2p-1)^n & \frac12 -\frac12(2p-1)^n \\ \frac12 -\frac12(2p-1)^n & \frac12 +\frac12(2p-1)^n \end{Vmatrix}[/math]
I solved this problem myself. Thanks to advise me to try to answer this question myself. It was easy to answer this question.
You've only shown that it's true for n=2, not for all n. That's where induction proof comes in.
If I were to ask you is it true for n = 100? Are you going to multiply the matrix 100 times?
Refer to post #3.
 
Top