2G band evacuation - Reduction

[eric4good]

Dear Experts

What is the best approach to prepare a high level design to reduce 2G spectrum, we currently operate 15Mhz in DCS1800 and want reduce it to 10 then 5 until complete evacuation.

What is the best high level calculation between available frequency numbers, TRX configuration, busy hour traffic etc.

Your valued inputs are appreciated

Thanks

[coach]

Hi,

You should first do an estimation of the overall TCH utilization of your network's (you can calculate the value with the current capacity and removing one or two TRX). Try to aim to remove as much capacity as possible while maintaining utilization below 60% on most sites.

Is there an underlying GSM900 network available, or the network is GSM DCS1800 only? If GSM900 is available, try to offload traffic to that band before everything else.

Regards,

[eric4good]

Thanks Coach, offloading is done to 3G, no other 2G band available, my question here is what is the maximum allowed cell TRX configuration for 5MHz, assuming this is my current target before final evacuation, and what can be done for hotspots with higher configurations

[coach]

With 5MHz you have 25 channels available. This is a very tight frequency reuse scenario, so using simulations to evaluate different scenarios is suggested.

The best solution would to use an AFP tool (Optimi, Schema, etc) to prepare an ad-hoc frequency plan using hybrid configuration (the same frequency can be used for BCCH or TCH). Schema does this pretty well. I'd suggest you to plan no more than two TRX per cell as a general rule (one hopping + one BCCH), and if you really must, allow some sites with 3 TRX (two hopping). In the cells with very low traffic, use only one TRX. Using an ad-hoc plan gives you some flexibility on this regard.

If no AFP tool is available, you would have to reserve some frequencies for BCCH (at least 13 I'd say), and use the remaining to build hopping lists (or no hopping at all). This would allow having 2 TRX per cell as well, but likely with higher interference than an ad-hoc plan.

Hope this helps,

Regards,