For 900: BCCH: 21 for 3 sectors (7 for each sector). MA list: 18 freqs
For 1800: BCCH: 24 for 3 sector (8 for each). MA list: 24 freqs.
For average, we have nearly 4 trx/cell. The largest configuration per cell may reach 12 when have 1 900 and 8 trx for 1800 (we have 2 MA list for 1800)-concentric configuration.
Yes, you are right, planning is very easy. HSN can even be the same for nearby site without KPI affected (if the sites are not synchronize). Of course for safety we plan them different. But the prob is we don’t know what to do when we have TCH interference 😀