Radio Cell Planning

Solution:

4 TRX = 8*4 = 32 channels

32-3 = 29 TCH

From Erlang B = 21.04 Er

21.04/25 mE = 950 Subscriber

Frequency Hopping

Frequency Hopping

Frequency Hopping

Frequency Hopping

Frequency Hopping

• Cyclic frequency hopping (HSN = 0) [HSN : Hopping Sequence Number]
• frequency changed in a consecutive order
• E.g. hopping over 4 frequencies:
• Cyclic sequence defined in GSM specification: goes from lowest ARFCN to the highest, and over again, in that channel group
• Random frequency hopping (HSN = 1 to 63)
• stored in a look-up table in MS & BTS = 63 defined
• e.g. hopping over 4 frequency:

Frequency Hopping

• MAIO (Mobile Allocation Index Offset)
• The MAIO Management feature provides increased control over frequency hopping to minimize channel interference within a site.
• The cells within the site needs to be synchronized!
• This is beneficial in a network with tight re-use of frequencies, such as 1/1 & 1/3.