Friday, July 29, 2011

Distance Calculator Tool for RF Engineers

Distance Calculator Tool for RF Engineers
Very Good tool You can Download.
Distance Calculator.
Its calculate distance between two latitude and longitude.



Tuesday, July 26, 2011

Brief describe the advantages and disadvantages of soft handover?

Advantages:
·         Overcome fading through macro diversity.
·         Reduced Node B power which in turn decreases interference and increases capacity.
·         Reduced UE power (up 4dB), decreasing interference and increasing battery life.
Disadvantages:
·         UE using several radio links requires more channelization codes, and more resources on the Iub and Iur interfaces.
More Dowload For You:

Monday, July 25, 2011

Why is there soft handover gain?

Soft handover gain comes from the following:
  • Macro diversity gain over slow fading.
  • Micro diversity gain over fast fading.
  • Downlink load sharing over multiple RF links.  By maintaining multiple links each link could transmit at a lower power, resulting in lower interference therefore a gain.
Just for you:

Download WCDMA IRAT Handover Document.


Thursday, July 7, 2011

Sometimes we say Ec/Io and sometimes we say Ec/No, are they different?

Io = own cell interference + surrounding cell interference + noise density
No = surrounding cell interference + noise density
That is, Io is the total received power density including CPICH of its own cell, No is the total received power density excluding CPICH of its own cell.  Technically Ec/Io should be the correct measurement but, due to equipment capability, Ec/No is actually measured.  In UMTS, Ec/No and Ec/Io are often used interchangeably.

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Wednesday, July 6, 2011

What is Ec/Io?

Ec/Io is the ratio of the energy per chip in CPICH to the total received power density (including CPICH itself).

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Downlaod Complete Document on UMTS Call Flow

Tuesday, July 5, 2011

Why is Eb/No requirement lower for PS than for CS?

PS has a better error correction capability and can utilize retransmission, therefore it can afford to a lower Eb/No.  CS is real-time and cannot tolerate delay so it needs a higher Eb/No to maintain a stronger RF link.

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Monday, July 4, 2011

What are the Eb/No targets in your design?

The Eb/No targets are dependent on the service:
  • On the uplink, typically CS is 5 to 6dB and PS is 3 to 4dB – PS is about 2dB lower.
  • On the downlink, typically CS has 6 to 7dB and PS is 5 to 6dB – PS is about 1dB lower.
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