CSI, channel State !!!!!!!!!!plz Help

Hi, What is the physical meaning of saying that "the CSI is known at Receiver or at transimitter" .I know that CSI is a channel state ,but when I counterd channel capacity calculation I found there are some differences between the CSI at receiver capacity and CSI known at transmitter and receiver , I couldn't I understand or imagine the meaning of these differences between them.

electronicman said:

Hi, What is the physical meaning of saying that "the CSI is known at Receiver or at transimitter" .I know that CSI is a channel state ,but when I counterd channel capacity calculation I found there are some differences between the CSI at receiver capacity and CSI known at transmitter and receiver , I couldn't I understand or imagine the meaning of these differences between them.

Click to expand...

Hi,

Channel State Information (CSI) has different meanings according to different situations. I discuss here CSI according to the description from a recent and to me very good book "MIMO Wireless Communications" by E. Biglieri et al. For comlete description of CSIT, CSIR, CDIT and CDIR please read chapter 2 of this book.

On page 27, authors define CSI as "instantaneous channel gains". According to my understanding and which i use in my research as well, CSI means two things, instantaneous channel gains or more accurately it shud be channel distribution. If transmitter (BS) knows the distribution of the channel then most of the information required to get ergodic (Shannon) capacity can be extratced from this distribution. I guess you know the meaning of CSIT, CSIR, CDIT and CDIR where T is for Transmittter and R is for Receiver and I is for Information and D is for Distribution. Usually receiver knows its channel state perfect (almost) but its hard to get that information at BS, where many factors involve. like delay in feedback, quantization error etc.

For further discussion on this topic please read chapter 2 of above mentioned book.

Regards.

Hope this will help you, if so press helped me !!

MAK