Algorithm for selecting the BTS to be optimized for MCDR Reduction. Reduction of MCDR (Mobile Call Defect Ratio) is one of the prioritized tasks on Network Quality. One of the approachs to decrease MCDR is to change physical and soft parameters of BTSs. Since human, time and other kinds of resources are limited, the process of selecting of BTSs to be optimized is important. Which BTS should be optimized first in order to achieve maximum select on the reduction of overall/total MCDR?

1. Algorithm for selecting the BTS to be optimized for
MCDR Reduction
Rahmatjon Hakimov
http://oftob.com, http://oftob.ru
rahmatjon at gmail.com
June 24, 2015
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 1 / 11

2. Overview
1 Problem statement
2 Definitions
3 Statements
4 Algorithm for selecting the BTS to be optimized
5 Example of SQL-script for Cell Weight calculation
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 2 / 11

3. Problem statement
Reduction of MCDR (Mobile Call Defect Ratio) is one of the
prioritized tasks on Network Quality.
One of the approachs to decrease MCDR is to change physical and
soft parameters of BTSs.
Since human, time and other kinds of resources are limited, the
process of selecting of BTSs to be optimized is important.
Which BTS should be optimized first in order to achieve maximum
effect on the reduction of overall/total MCDR?
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 3 / 11

4. Definitions
# of defective calls = (# of failed calls) + (# of dropped calls)
MCDR = total # of defective calls
total # of call attempts
DPMO - Defects Per Million Opportunities
MCDR DPMO = total # of defective calls
total # of call attempts ∗ 1000000 or
MCDR DPMO = MCDR ∗ 1000000
BTS MCDR = # of defective calls in BTS
# of call attempts in BTS
BTS MCDR = BTS MCDR ∗ 1000000
BTS MCDR Weight =
= MCDR −
(# of defective calls) - (# of defective calls in BTS)
(# of call attempts) − (# of call attempts in BTS)
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 4 / 11

5. Statements
Let:
wj be BTS #j MCDR Weight
mj be number of defective calls in BTS #j
nj be total number of calls in BTS #j
m be total number of defective calls in the network
n be total number of calls in the network.
Statement 1
BTS #j MCDR Weight is equal to 0, if and only if, its MCDR is equal to
Total MCDR:
wj = 0 ⇐⇒
mj
nj
=
m
n
.
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 5 / 11

6. Statements (cont.)
Statement 2
BTS #j MCDR Weight is greater than 0, if and only if, its MCDR is
greater than Total MCDR:
wj > 0 ⇐⇒
mj
nj
>
m
n
.
Statement 3
BTS #j MCDR Weight is less than 0, if and only if, its MCDR is less than
Total MCDR:
wj < 0 ⇐⇒
mj
nj
<
m
n
.
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 6 / 11

7. Statements (cont.)
Statement 4
Assume w1 > wj ∀j = 2, ..., k. Then
m − m1
n − n1
<
m − mj
n − nj
∀j = 2, ..., k.
Statement 5
If the number of defective calls in the BTS #j becomes equal to
m
(r)
j =
m(rnj − nj ) + mj (n − rnj )
r(n − nj )
,
then its weight in the total MCDR decreases r times.
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 7 / 11

8. Statements (cont.)
Assume that BTS #j was chosen for optimization and during the
optimization:
A0) number of call attempts in this and all another BTSs does not change;
B0) number of defective calls in another BTSs does not change.
Statement 6
If number of defective calls in BTS #j is decreased from mj to
m∗
j =
(m−mj )nj
n−nj
, then:
1. Total MCDR decreases from m
n to
m−mj
n−nj
, i.e. minus wj .
2. BTS #j MCDR Weight becomes equal to 0.
Corollary
If BTS with the highest weight in total MCDR is chosen for optimization
and assumptions A0 and B0 are met, then the reduction of this BTS’s
MCDR Weight to 0 gives the maximum effect on Total MCDR reduction.
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 8 / 11

9. Algorithm for selecting the BTS to be optimized
1 Calculate the Total MCDR.
2 Calculate MCDR Weight of each BTS.
3 Find BTS #j with the highest MCDR Weight wj .
4 Decrease number of defective calls in BTS #j (from mj to m∗
j ).
5 Recalculate the Total MCDR.
6 Go to step 2, if it is necessary.
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10. SQL-script for Cell Weight calculation
Example (Code for Oracle 10g)
/* Formatted on 03-July-2014 15:45:40 (QP5 v5.160) */
SELECT t1.dt, t1.cell,
t1.call_attempts, t1.failed_calls, t1.dropped_calls,
(t1.dropped_calls + t1.failed_calls) / t1.call_attempts
* 1000000 mcdr_dpmo,
((t2.dropped_calls + t2.failed_calls) / t2.call_attempts
- ( t2.dropped_calls - t1.dropped_calls
+ t2.failed_calls - t1.failed_calls)
/ (t2.call_attempts - t1.call_attempts))
* 1000000 weight_dpmo
FROM report.mv_mcdr_3g_detail t1, report.mv_mcdr_3g t2
WHERE t1.dt = t2.dt AND t1.call_attempts > 0
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11. Thank you!
Rahmatjon Hakimov (http://oftob.com) Algorithm for MCDR Reduction June 24, 2015 11 / 11