Title Frequency Management and Channel Assignment Duplex (Telecommunications) Cellular Network Data Transmission Telecommunications Engineering 253.1 KB 22
```                            Frequency Management and Channel Assignment
12.1 Introduction
12.2.1 Frequency management chart
12.2.2 Grouping into subsets
12.3 Set-up channels
12.3.1 Access channels
12.3.2 Paging channels
12.4 Traffic and channel assignment
12.4.1 Fixed channel assignment
12.4.2 Dynamic channel assignment
12.4.3 Channel sharing scheme
12.4.4 Channel-borrowing scheme
12.5 Channel assignment algorithms
12.6 Simulation process and results
Method of implementation
Reuse distance
12.6.1 Blocking
Average blocking
Handoff blocking
12.7 Summary
Example problem 12.1
Solution
Example problem 12.2
Solution
Example problem 12.3
Solution
Review questions
Open book questions
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##### Document Text Contents
Page 11

o Determine the state of the vehicle in the cell (idle, off-hook, on-hook, and
handoff).

Method of implementation

There are many different ways of implementing FBCA. In a general

sense, FBCA can also be applied while accounting for the forcible

borrowing of the channels within a fixed-channel set to reduce the

chance of co-channel assignment in a reuse cell pattern.

Reuse distance

The FBCA algorithm is based on assigning a channel dynamically but

obeying the rule of reuse distance. The distance between the two cells is

reuse distance, which is the minimum distance at which no co-channel

interference would occur. If all the channels in the neighbouring cells

cannot be borrowed because of interference problems, the FBCA stops.

12.6.1 Blocking

Two types of blocking are possible in FBCA algorithm:

1. Average blocking: It happens mostly in non-uniform traffic.
2. Handoff blocking: It happens mostly in uniform traffic.

Average blocking

Two average blocking cases illustrating this simulation are shown

in Figure 12.3. In a uniform traffic condition (Fig. 12.3(a)), the 3 per cent

blocking of both BCA and FBCA will result in a load increase of 28 per

cent, compared to 3 per cent blocking of FCA. There is no difference

between BCA and FBCA when a uniform traffic condition exists. In a

non-uniform traffic distribution (Fig. 12.3(b)), the load increase in BCA

drops to 23 per cent and that of FBCA increases to 33 per cent, as at an

average blocking of 3 per cent. The load increase can be utilized in

another way by reducing the number of channels. The percent increase

in load is same as the percent reduction in the number of channels.

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