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Thursday 10 June 2010

Relationship between frequency & capacity, in-building penetration & cell size


Interesting picture from a presentation by Prof Ed Candy Hutchison Whampoa Europe & 3 Group Europe in the LTE World Summit.
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10 comments:

  1. Anonymous10 June 2010 at 09:20

    I don't understand this, provided that you can have the same bandwidth, why should capacity change?

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  2. Zahid Ghadialy10 June 2010 at 10:16

    The higher the frequency, the lower the propagation of waves assuming constant power. This means smaller cell size.

    See also: http://3g4g.blogspot.com/2009/07/800-or-2600mhz-frequency-impact-on.html

    ReplyDelete
  3. Anonymous10 June 2010 at 10:24

    Oh yes, the coverage part is clear, my comment was about capacity ;-)

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  4. Zahid Ghadialy10 June 2010 at 10:34

    Doh! Of course the capacity will remain the same. The capacity part is not correct on the picture.

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  5. Anonymous10 June 2010 at 15:00

    Actually, when cell radius decreases, there will be more sites in the network which means more capacity.

    ReplyDelete
  6. Anonymous10 June 2010 at 15:52

    Yes, that's true, but then the comparison is not quite fair, we need a third axis then with the variable $$$ :-)

    Same bandwidth, Same money, Higher frecuency => less coverage, same capacity.

    ReplyDelete
  7. Sathees11 June 2010 at 06:09

    Hi, Thanks for the Picture !

    If we have 10 MHz bandwidth in 900Mhz and 10MHz in 2.3GHz, then capacity of 900MHz and 2.3GHz are the same? Please clarify

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  8. Zahid Ghadialy11 June 2010 at 11:57

    Yes, the cell capacity should remain the same but as someone rightly pointed out above, the radius of the cell will decrease and hence you will need more cells for the same area of coverage. This would in turn increase the network capacity.

    ReplyDelete
  9. Sathees14 June 2010 at 09:23

    Hi, Thanks.
    900 Mhz = 900000 cycles per second,
    2300Mhz = 2300000 cycles per second

    that means 2.3GHz can carry more data in given time than 900MHz. So according to this, 2.3GHz will get more data rate than lower band..isn't it?

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  10. Zahid Ghadialy14 June 2010 at 11:08

    Hi Sathees, The frequencies we are talking about is the Modulating frequency. The data remains the same regardless of the frequency. The modulation translates the data into the frequency to be transmitted and at the receiver side the demodulator receives the sata at the higher frequency and translates it back onto the lower frequency.

    An RF engineer should be able to better explain what I have said.

    ReplyDelete