Frequency Reuse Factor | Co-Channel Interference & Signal To Interference Ratio
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- เผยแพร่เมื่อ 26 ธ.ค. 2020
- Frequency Reuse Factor | Co-Channel Interference & Signal To Interference Ratio explain about cellular concept like what is co-channel interference in cellular system. Next you will learn about signal to interference ratio calculation and in the end I have explain about worst case scenario with omnidirectional antenna.
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#wirelesscommunication #cochannelinterference #signaltointerferenceratio
At 7:23 is the signal power value is equal to 1?
S / I = 1/6(q)y. Are you asking about this equation (numerator is 1) or something else?
@@ecit Numerator should be Signal power ..but here it is written as 1..is signal power is equal to 1 sir?
@@gireeshkumarkancharla4176 No, Signal Power will not become 1. It was my mistake while recording this lecture. Signal power will depend upon S = R ^ -gamma and Interference will depend upon I = D ^ - gamma. So, for S/I ratio (with D/R) numerator will become 1.
Thus, Signal power will depend upon the amount interference.
@@ecit Sir at 6:26..Numerator is 1or S?
@@gireeshkumarkancharla4176 nice observation, in second equation (below) , it will be 1 instead of S.
Reason I already told you in previous comment.
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Informative and easy to understand, good explanation 👍
Thanks 😊
This is good sir but we moredegails lectures and numerical for our exam ... thank you sir
Thank you for your feedback! Go through wireless playlist on my channel.
Thank You sir, very nice explaination ✌🏻
Thanks for your valuable feedback
Thank you sir for good explanation ..,👍
Thank you 😊
you are a very good teacher
Thank You! 😊
sir can you please continue this series we need this type of content masterpiece in wireless communication
Thanks for your feedback. Can you tell me the chapter names ?
pathloss models , diversity ,two ray model, delay spread ,doppler spread
@@ecit
@@umeshsinha6388 ok, I will upload this video by next month.
good videos .simply explained
Thank You!
Thank you sir
You are welcome, keep learning!
Thanks
Welcome!
Sir what is the value of gamma
Gamma is path loss exponent, sometime also mention as 'n'.
Range of Gamma is 2 to 5.
For free space Gamma value is 2,
Gamma is varying as environmental conditions are changing, example free space, rural areas, urban areas etc.
how ,we take the value of S is equal to 1?
Please read pinned message
Suppose that microwave antennas (eg frequency 18 GHz) are placed horizontally at some distance and that one is slightly shifted horizontally (or vertically) so that its maximum radiation is not in the horizontal axis. If both antennas have the same transmission power, the same gain, the same polarization, the same losses of waveguides and connection points, will the signal strength at the reception of both antennas be the same and why? If not, why not?
This is called as mechanical tilt in telecom, although all the electrical properties of both antenna is same however if you change angle or orientation of antenna then its covering area will also change thats why you will different signal strength special at the edge of main lobe.
Thank you for your reply. The assumption here is that the orientation of only one antenna is changed. Which of the antennas, the one whose orientation does not change (maximum radiation in the horizontal axis towards the second antenna) or the one whose orientation is slightly changed (no maximum radiation in the horizontal axis towards the second antenna) will have a stronger reception signal and why. Is it possible to show this by calculation?
@@ivanrados2443 It is possible by calculation however I don't have that calculation now.
Thank you for your reply. Does anyone know the answer to this question: Which of the antennas, the one whose orientation does not change (maximum radiation in the horizontal axis towards the second antenna) or the one whose orientation is slightly changed (no maximum radiation in the horizontal axis towards the second antenna) will have a stronger reception signal and why.
Sir one doubt sir why for worst caseof co channel interferance why we are taking edge of hexagon cell sir
Are you talking about sector? Co-channel interference occurs between cells or sector having same frequency. And it is worst if two co-cells are near to each other.
@@ecit no sir in 4:21 you have taken worst case of co channel interferance at the edge of hexagon cell sir
@@gadamchettyrahul2154 ok if user is at center of the cell then distance from all co cells will be equal and there will be no interference or very less interference. But if user is at cell boundary then as you can see in the image there are two co cells which are close to user and that can cause more interference. Watch full video carefully, in the end we made calculation for closest cell too
what means negative Carrier to Interference (C / I ratio)
C/I ratio is carrier or signal power to Interference or Noise power, and it is in log.
C/I = 20 log (Cp/Ip)
= 20 ( log (Cp) - log (Ip) )
So, when Interference is greater than carrier power, C/I will goes negative.
@@ecit Thank you for the quick response. I will be free to ask one more question: why is the C/I for co-channel interference positive and for adjacent-channel interference negative (I saw this in the Ericsson documentation). Let the radio equipment manufacturer set C/I=20 dB for 3 dB increase of BER limit, if a specific calculation gives C/I=16 dB, does this mean that it is not good and that it is necessary to take appropriate actions (the question is which one? ) to obtain C/I>20 dB. The same is true for negative C/I.
@@ivanrados2443 well if C/I is below the required threshold, which can be 16dB, then you may take following actions.
1. Increase carrier power in such a way that it will not create interference to other cell.
2. You may adjust the antenna angle
3. During the design phase, you can use cell sector and cell splitting concept. (This are theoretical suggestions)
I don't have enough practical knowledge to provide you exact answer.
@@ecit Thank you for your reply
why is C/I positive with co-channel interference and C/I negative with adjacent channel interference (Ericsson documentation)