2. Understanding Cell site Infrastructure
A cell site is a cellular telephone site where antennas and electronic communications
equipment are placed, usually on a radio mast, tower or other high place, to create a cell (or
adjacent cells) in a cellular network. The elevated structure typically supports antennas, and
one or more sets of transmitter/receivers transceivers, digital signal processors.
A cell site is sometimes called a "cell tower", even if the cell site antennas are mounted on a
building rather than a tower. In GSM networks, the technically correct term is Base
Transceiver Station (BTS), and colloquial British English synonyms are "mobile phone mast"
or "base station". The term "base station site" might better reflect the increasing co-location
of multiple mobile operators, and therefore multiple base stations, at a single site. Depending
on an operator's technology, even a site hosting just a single mobile operator may house
multiple base stations, each to serve a different air interface technology (CDMA2000 or
GSM, for example).
Telecom Infrastructure
Basically a cell site consists of electronic (active) and non-electronic infrastructure.
•Electronic infrastructure includes base tower station, microwave radio equipment,
switches, antennas, transceivers for signal processing and transmission.
•Non-electronic infrastructure includes tower, shelter, air-conditioning equipment,
diesel electric generator, battery, electrical supply, technical premises and easements &
pylons that account for nearly 60 percent of network rollout costs
3. Module
1 Intro to SIMS
2
3
4
Routine Maintenance
Generator Maintenance
Fault Resolution & Other Terms
5. Site Integrated Maintenance
SIMS – Site integrated Maintenance Services
Passive
- Routine and
Non Routine
Active
- Link
Maintenance
SIMS
6. Intro to SIMs
Passive Maintenance comprises of:
• Routine Maintenance
• Non Routine Maintenance
7. Intro to SIMs
Routine Maintenance comprises of the following task:
DC Power maintenance
Diesel Delivery and Management
Security Services
Mechanical Maintenance which include Fence, Shelter and AC maintenance
Tower member maintenance
Janitorial Cleaning
Above are undertaken monthly expect tower and mechanical maintenance which are
quarterly
Non routine maintenance takes charge of sudden fault repairs(Minor/Major) such as
complete/partial overhauling(Knocked Engine), fan belt replacement, PHCN
Infrastructures and other services not captured in the SOW.
Necessary approval must be sought before implementation.
9. Routine Maintenance
Routine Maintenance includes activities that need to be carried out on a
regular basis on intervals as defined in the MTN Contract.
The regular maintenances are contractual obligations aiming at prolonging the life
expectancy of the MTN equipments/assets through preventive actions and early
detections of problematic issues.
Well planned and systematic execution of Routine Maintenance has also direct
impact on the quality of deliverables.
They allow reduction and better management of unexpected events. Thereby,
reduces the strain and stress imposed on the team and avoid the fire fighting
scenario.
TERMS
MTTR - Mean Time To Resolve( 2hrs)
MTBF - Mean Time Before Breakdown
NB MTBF> MTTR = Zero down time
10. Routine Maintenance
SLA FOR MTN ROUTINE MAINTENANCE
MAIN DELIVERABLES TASK WKLY
Every 2
WKS Mthly 1/4ly Yrly 250 Hrs 1000 Hrs 2400Hrs
Tower
Tower X X
Foundation X X
Obstruction Lighting X X
Earthing System X X
Locking Devices X
Vertical Alignment X
Mechanical
Fence X
Equipment Housing X
Air Conditioning Unit X
Site Security
Assessment X
Recommendation X
DC Maintenance
Rectifier X
Battery X
UPS X
Utility
PHCN Connection X
PHCN Status &
Quality X
PHCN Related
Problem X
Generator
Generator Running X X X
ATS X
AVR X
Diesel Level
Verification X
Janitor
Fumigation X
General site cleaning X
12. Generator Maintenance
Generators are serviced depending on the Run Hour, brand, capacity and model as
stated below:
ASSUMPTIONS
SITE WITH PHCN SITE WITHOUT PHCN
GEN TYPE : 1000RH GEN TYPE : 250RH GEN TYPE : 1000RH GEN TYPE : 250RH
MONTH
LY
SERVICI
NG
FREQ in
DAYS
MATERIALS
MONTH
LY
SERVICI
NG
FREQ
MATERIALS
Oil
Filter
Fuel
Filter
Engine
Oil
MONT
HLY
SERVIC
ING
FREQ
Oil
Filter -
1pc/Se
rv
Fuel
Filter
Engine
Oil
Oil
Filte
r
Fuel
Filte
r
Engine
Oil
MONT
HLY
SERVIC
ING
FREQ
Oil
Filter -
1pc/Ser
v
Fuel
Filter
Engine
Oil -
8ltrs/S
erv =
25ltrs
BEST CASE :
PHCN
AVAILABILTY -
12hrs. GEN -
12hrs 83
1 1 55ltrs
21 1 1
8 ltrs
42
1 1 55ltrs
10.4166
67
3 3 25 ltrs
AVE CASE :
PHCN
AVAILABILTY -
6hrs. GEN - 18hrs 56 14 2 2
WORST CASE :
PHCN
AVAILABILTY -
3hrs. GEN - 21hrs 48 12 3 3
HYBRID :
AVAILABILTY -
8hrs.
GEN - 16hrs 63 16 2 2
13. Other Services
Diesel Delivery – This is a function of generator age, load and site capacity as
volume and consumption are dependent on above variables
15kva BTS site without PHCN – 1850 ltrs
27kva Backbone site without PHCN – 2400ltrs
15kva BTS site with PHCN – 1100ltrs
After every diesel delivery , it is important to record the generator RH as this helps
to determine generator daily consumption.
Timely and accurate diesel delivery help reduce DOWNTIME to the minimal as
this(Diesel) represent the hub of MS.
15. Fault Resolution
All fault are expected to be cleared within the allowable time limit – 2hrs,
failure reduces SMC’s availability(98%) measured in percentage. Else penalty of
113,500/ hour starts counting.
Mobile gen must be deployed to rescue site during major fault that cannot be
resolved within 2hrs to avoid penalty charges.
Ref must provided by MTN NMC before site access
Battery back must be in top gear to avoid unnecessary down time
All alarm system must be wired and functional
All opened ticket must be closed via necessary feedback from field engr. to
MTN NMC/NOC.
16. Other Terms
Mean time between failures (MTBF) : is the predicted elapsed time between inherent
failures of a system during operation. MTBF can be calculated as the arithmetic mean
(average) time between failures of a system.
Mean Time To Repair (MTTR) : is the time needed to repair a failed hardware
module.
Availability: Availability of the module is the percentage of time when system is
operational. Availability of a hardware/software module can be obtained by the formula
given below. A = MTBF/ MTBF+ MTTR
Failures : Total period an equipment was unable to achieved its main objectives.
Remedy : Place where fault log are stored/ Kept for future reference
