Digital GSM Repeater Architecture

Hi,

We are trying to design a Digital GSM Repeater operating at 900/1800 MHz bands. It would mainly comprise of a “Digital Down Converter” and “Digital Up Converter”. Please suggest, what kind of receiver and transmitter architecture is preferred between a Homodyne and Heterodyne architecture?

Thanks in advance.
Ashwani

While ago because cost due to low volume of repeaters and basestations was not very important, Heterodyne was preferred instead Homodyne because performances were better.
But the new RFIC technologies allow now Homodyne to reach almost the same performances as Heterodyne, with much less cost.

Thanks for your reply.

As you said homodyne architecture reaches almost the same performances as Heterodyne, with much less cost as compared to heterodyne architecture.

Please let us know, would a homodyne architecture based design meet the ETSI GSM repeater specifications?

References of any GSM Digital repeater solution or products using homodyne architecture would be appreciated.

regards
Ashwani

I don’t know if is available any chipset transceiver for GSM repeater using Homodyne architecture, but I know that ADI makes one for WCDMA. Search or ask the main manufacturers if they have, or intend to make something like this in the near future: Infineon, NXP, Skyworks, Renesas, Freescale, TI, ADI, etc.

We are considering using of a Quadrature Demodulator for our Digital GSM repeater product assuming Homodyne Architecture. The choice of a Quadrature Demodulator (ZIF Rx) could reduce the BOM cost dramatically.

Does using a Quadrature demodulator reduce ADC sampling rate by half in case of GSM (GMSK modulation)? Eg. given in attach file.

rds.
Ashwani[/img]

Hi,

In Digital GSM900/1800 receiver having single IF stage (70 MHz), typically what are the antialias and image reject filters have been used?

References of any antialias and image filters part number for GSM 900/1800 would be appreciated.


Regards
Ashwani