Continue to Site

Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Register Log in

GSM 900 Repeater design

Status
Not open for further replies.
Z

zac79x

Newbie level 3
Joined
Jan 15, 2007
Messages
4
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Activity points
1,312
First hello to all, it should be my first post here...
I'm "trying" to design a GSM 900 repeater with this scheme:
directive antenna --> LNA --> AMP+AGC --> PA --> omni antenna
directive antenna <-- AMP <-- AMP+AGC <-- omni antenna
The antennas are the same, i'm using diplexers on every side.
So the questions:
How much total gain for the upper side (and bottom side) amps, if i want a functioning repeater for a weak outside signal ?
What power outputs should i use on the PAs ?
Some papers or links to informations ?
 

Nobody ?? Any suggestions ?
 

Hi,

U question is to general!
u rest a lot of parameters

when u say weak signal how much do u mean


In general (i will put some parameters of my system) :
u will receive from BS to Repeater between -60dBm ÷ -90dBm.
Your PA suppose to be about 30dBm (again all numbers depend on distance and of course mobile channel parameters like do u transmit LOS etc...)
One of the most important parameters is DL total + UL total Gain suppose to be less then isolations of the both diplexers (from tx to rx) by factor of 12dB at least.

David

Added after 1 minutes:


In my system:

DL gain was Glna=60dB, G_PA=30dB
UL gain was Glna=45dB, G_PA=30dB

David
 

    Z

    zac79x

    Points: 2
    Helpful Answer Positive Rating
Sorry for the missing parameters, but it's a new field for me. Some data:
Uplink 890-915 MHz, Downlink 935-960MHz
I'm thinking about a class B or hybrid broadband repeater. The service antenna should be capable of a near field coverage of about 20m*20m. This should be a BDA for home or office use in GSM band only.
I have problems finding suitable SAW filters, so i'm not able to obtain high TX-RX isolation...
For the PA stage i'm trying to use RF2104, for the LNA the AVAGO'S ATF33143. Interstage amps use broadband MMIC or BJT transistors.
Admitting I receive -90dBm at the donor antenna, and I want a near field coverage of about 20m+20m, are -10dBm at the service antenna enough ?
 

Hi,

Please expain: I want a near field coverage of about 20m+20m.

David

Added after 6 minutes:

Hi,

About the saw filters
try to look for them at: EPCOS and Sawtec (triquint) (may be that i made a mistake with the names but they PRETTY SURE THEY WILL HAVE IT!)

David
 

    Z

    zac79x

    Points: 2
    Helpful Answer Positive Rating
I made a mistype, i meant 20m*20m field coverage near the service antenna (supposing an omnidirectanional antenna). The donor antenna has to placed with a sufficient distance from the service antenna.Your answers and suggestions are appreciated!
 

Okay,

If u need something else please let me know!

David
 

HI to ALL,
Can anyone tell me the Schematic of GSM Repeater.plz reply me at:sykh84@msn.com
 

Hi,

What is the numbers of carriers in GSM900 0.8 MHz band.
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Back
Top