Comments on: BER for BPSK in ISI channel with Zero Forcing equalization

By: Krishna Sankar

Krishna Sankar — Mon, 28 Jun 2010 01:17:16 +0000

@vsk: In a MIMO ISI case, convolve each transmit stream with the channel seen from each transmit stream to receive antenna.
For eg, if
h11 – channel between transmit antenna 1 to receive antenna 1
h12 – channel between transmit antenna 2 to receive antenna 1
h21 – channel between transmit antenna 1 to receive antenna 2
h22 – channel between transmit antenna 2 to receive antenna 2

The received symbol on receive antenna 1
y1 = conv(h11,x1) + conv(h12,x2) + n1
y2 = conv(h21,x1) + conv(h22,x2) + n2
and x1, x2 are transmit symbols from antenna 1 and 2 respectively.

Do NOT sum all the impulse response and represent them as a single value.

By: vsk

vsk — Fri, 25 Jun 2010 21:16:23 +0000

Hi Mr.Krishna,
For a MIMO system, how do I model an ISI channel? Meaning do I sum the impulse responses for the various paths from antenna i to antenna j and denote it as a single co efficient in the H matrix as h(ji)?
And so how do I perform ZF-SIC for the same case?

By: Krishna Sankar

Krishna Sankar — Sun, 18 Apr 2010 09:16:39 +0000

@Ali: Try changing the creation of the Toeplitz matrix such that h3 comes in the diagonal term…

By: Krishna Sankar

Krishna Sankar — Sun, 18 Apr 2010 09:11:24 +0000

@Newbie: A channel whose taps do not vary with time is a time invariant channel

By: Ali

Ali — Thu, 15 Apr 2010 16:33:18 +0000

Hi i have a question regarding the ZF-equlization, what if the desired tap is at the last position?
h = [0.3 0.1 0.9]. I tried to change the code but i could not.

By: Newbie

Newbie — Wed, 14 Apr 2010 14:58:14 +0000

Hiii Mr.Krishna

Thank you for ur post, that is help me so much. That is time invariant channel???

By: Krishna Sankar

Krishna Sankar — Sat, 03 Apr 2010 23:50:28 +0000

@Ananthi: Thanks