of bearer services. Notice it does not include voice services. Table 7.5 Traffic Data Example for 50 and 75% Population Coverage Active subscribers at 50% popula- 21000 80000 265000 70000 30800 tion coverage Active subscribers at 75% popula- 22000 110000 350000 110000 401000 tion coverage Busy hour traffic/subscriber UL Bearer UDD64 (kbit/s) 0.079 0.079 0.079 Bearer UDD144 (kbit/s) 0.060 0.060 0.060 Bearer UDD384 (kbit/s) 0.015 0.015 0.015 Bearer LCD64 (mErl) Bearer LCD144 (mErl) Busy hour traffic/subscriber DL Bearer UDD64 (kbit/s) 0.120 0.120 0.120 Bearer UDD144 (kbit/s) Bearer UDD384 (kbit/s) Bearer LCD64 (mErl) Bearer LCD144 (mErl) The traffic data, i.e. Unrestricted Delay Data (UDD) and Low delay Circuit Switch Data (LCD) for the different environments (Dense Urban (DU), Urban (U), Industrial (IND), Suburban (SU), Forest (FO), and Open (OP)), represent the possible traffic flow in the 3G network. We provide them here only as reference to make realistic projections. No- tice that the traffic in the DL is higher than in the UL due to the fact the users download The UMTS Network and Radio Access Technology more information than they upload. We can also see that a good part of the subscriber base remains in the open areas in this particular density distribution. Consolidating 3G BS areas will vary from region to region. Some regions have already strict regulations for the implementation of sites as well as high costs in dense areas. This means that site acquisition will exceed the minimum requirements. Thus, Table 7.5 shows the necessary margins projected for subscriber growth assuming that sites can be available within a short term. The turnaround to prepare sites to increase coverage and capacity may not necessarily match a rapid subscriber growth. If we apply 50% of the population coverage to the 1st case and 75% to the 2nd case, we then have about 750K UMTS subscribers for the initial phase and about 1000K for the latter. This means we dimension the 3G network initially with enough margin for growth towards 