Decision Process : Get System Load: Find Channel Numbers

Step 9 : Find Channel Numbers When you determine the number of channels needed, it is important to specify the capacity for growth. The best way to understand this is to follow the example. Assume: 2% blocking For each technology, use the Erlang-B tables to find: Omni AMPS 24 traffic channels give us enough for this site (16.63 Erlangs) TDMA 24/3 = 8 traffic channels (24 timeslots for traffic) GSM 24/8 = 3 traffic channels (24 timeslots for traffic) CDMA at least 2 carriers (7.4 Erlangs/carrier) Sectorized   AMPS Alpha: 13 channels give us enough for this sector (7.4 Erlangs)   Beta: 9 channels give us enough for this sector (4.3 Erlangs)   Gamma: 11 channels give us enough for this sector (5.8 Erlangs) TDMA Alpha: 13/3 = 5 traffic channels (13 timeslots for traffic)   Beta: 9/3 = 3 traffic channels (9 timeslots for traffic)   Gamma: 11/3 = 4 traffic channels (11 timeslots for traffic) GSM Alpha: 13/8 = 2 traffic channels (13 timeslots for traffic)   Beta: 9/8 = 2 traffic channels (9 timeslots for traffic)   Gamma: 11/8 = 2 traffic channels (11 timeslots for traffic) CDMA Alpha: 1 carrier (7.4 Erlangs/carrier)   Beta: 1 carrier (7.4 Erlangs/carrier)   Gamma: 1 carrier (7.4 Erlangs/carrier) Decision: Is the number of channels/cell required less than the cell capacity? At this point, reference your frequency plan to decide which route to take. It is important to keep in mind the customer's expectations regarding capacity for growth. In this example, these numbers are a bit high for an omni site, but may be workable. If our frequency plan and interference requirements can provide 24 channels, yet still meet our C/I requirements within the system, then this site can be set up as an omni site. Otherwise, a sectorized site is more appropriate. Continue with Step 10: Estimate Interference Levels.

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Design, Format, Edit, Graphics, etc is the work of Gary Wagoner along with an 11 member development team.