Cellular Systems Cellular Concepts The cellular concept was a ...

EE5401 Cellular Mobile Communications
EE5401 Cellular Mobile Communications
• Divide the total number of channels into two groups,
one of which is used for fixed allocation to the cells,
while the other is kept as a central poor to be shared
by all users.
• Mix the advantages the FCA and DCA, available
schemes are scheduled and predictive.
Channels need to be assigned to users to accommodate
- new calls
- handovers
With the objective of increasing capacity and
minimizing probability of a blocked call.
System Expansion Techniques
As demand for wireless services increases, the number
of channels assigned to a cell eventually becomes
insufficient to support the required number of users.
More channels must therefore be made available per
unit area.
• This can be accomplished by dividing each initial cell
area into a number of smaller cells, a technique
known as cell-splitting.
• It can also be accomplished by having more channels
per cell, i.e. by having a smaller reuse factor.
However, to have a smaller reuse factor, the cochannel
interference must be reduced. This can be
done by using antenna sectorization.
Cell splitting
• Cell splitting increases the number of BSs in order to
increase capacity. There will be a corresponding
reduction in antenna height and transmitter power.
• Cell splitting accommodates a modular growth
capability. This in turn leads to capacity increase
Institute for Infocomm Research 73 National University of Singapore
Institute for Infocomm Research 74 National University of Singapore