Inquiry: GSM WCDMA and LTE guard band in multiradio standard

[wsoong]

BACKGROUND
We are currently doing some study regarding spectrum re-farming. Our designed is to have GSM(900+1800)+WCDMA(900+2100)+LTE(1800).
In our project there are 2 frequency band required MSMM= Multi Standard Mixed Mode using RBS6000 which show below.

1. GSM (1800) +LTE (1800)
2. GSM (900) +WCDMA (900) .

QUESTION:
What is the channel spacing required to have both technology in the same band for below scenario?
1. GSM (1800) +LTE (1800) 0kHz or 300kHz ?
2. GSM (900) +WCDMA (900) 0kHz based ?

Regards.

[wsoong]

Hi,

Nobody have LTE experience with multi standard radio in this forum? Appreciates if some one can shed some light here. :(

Regards,