Cellular Mobile Network Basic.pptx

Where do mobile phone fits in Electromagnetic Spectrum

According to ITU Radio Regulation and NFAP*,

BTRC is the Government body for providing Telecom License and Spectrum

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824 – 849 (UL) , 869 – 894 (DL) MHz - E-GSM 890 – 915 (UL) , 935 – 960 (DL) MHz - GSM 900 1710 – 1785 (UL) , 1805 – 1880 (DL) MHz - GSM 1800 1920 -1980 (UL) , 2110-2170 (DL) MHz - UMTS (3G) 2500 – 2690 MHz (UL & DL) – 4G

*Bangladesh National Frequency Allocation Plan, BTRC

Where we Stand in terms of Spectrum?

Frequency Allocation (MHz) of Different Operator Teletalk

GP

5.2

10

7.4

Robi

Banglalink

10

19.6

9

5

15.6

Operator

Total (MHz)

Teletalk

25.2

4.6

0.18

Banglalink

30.6

32.4

1.06

Robi

36.4

44.2

1.21

GP

37

65.9

1.78

10

17.4

10

10

SUBSCRIBER Per MHz (IN MILLIONS)

SUBSCRIBER* (IN MILLIONS)

*Subscriber Data is from BTRC Publication, January 2018

GSM 900

GSM 1800

UMTS 2100

Key Points  In Terms of Spectrum, BL stands in 3rd Position but most importantly BL stands in 1st position when considering “Subscriber Per MHz” (Ignore Teletalk)  BL got Tech Neutrality License and now it’s possible to provide services to any spectrum like 4G in 1800/900 Band, 3G in 900/1800 Band etc.

How the Spectrum is used in the Network? Spectrum according to ITU and NFAP Downlink Range (MHz) GSM 900 890 to 915 935 to 960 GSM 1800 1710 to 1785 1805 1880 Band

Uplink Range (MHz)

Total GSM Channel Max ARFCN BW BW Number (MHz) (KHz) 25 200 125 75 200 375

Banglalink Band

Total BW (MHz)

900 1800 (2G)

5 10

1800 (4G)

5.6

GSM Channel GSM Max BW ARFCN Usable Channel (KHz) Number 200 25 24 200 50 49 5 MHz is using for LTE (Re farming also possible)

Spectrum according to ITU and NFAP

Spectrum according to ITU and NFAP

Downlink 3G Channel Total BW Number Range BW (MHz) of Carrier (MHz) (MHz) 2100 1920 -1980 2110-2170 60 5MHz 12

Banglalink got “Tech Neutrality” License so can deploy LTE in any purchased Band

Banglalink

Banglalink

Band

Uplink Range (MHz)

Band

Total BW (MHz)

2100

10

3G Channel Number of BW Usable Bandwidth Carrier (MHz) 5 MHz 2 3.45 MHz in each carrier

Same Frequency is used everywhere, Subscriber is identified by codes

Frequency reuse

2G

3G

Tx BW 1.25 MHz 2.5 MHz 5 MHz 10 MHz 15 MHz 20 MHz

Banglalink use 1800 band for deploying LTE and the transmission bandwidth is varies between 5 and 10 MHz

Same Frequency is used everywhere, Subscriber is identified by codes

4G

Benefits of advanced Technology

4G    

3G 2G

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IP Based Mobility Very High Speed Data VoIP All Packet Switching 3G 2G 2G 171 kbps 384 kbps 2 Mbps

High Quality Voice High Speed Data All Packet Switching

1G        

Digital Signal Advanced Mobility Voice, Data, SMS, MMS Circuit & Packet Switching

Analog Signal Basic Mobility Voice only Circuit Switching

1. 2. 3. 4.

Single Carrier (5MHz) Dual Carrier (10 MHz) LTE 5MHz with 2X2 MIMO LTE 10MHZ with 2X2 MIMO

3G 14 Mbps

4G 3G 3 1 21 Mbps 50 Mbps 4 42 Mbps2 100 Mbps

Coverage/Signal Strength Antenna Height and Tilting

Coverage  Coverage of a BTS depends on following points    

Antenna Height and Tilting BTS output power (20/40 Watt) and sensitivity MS output power (2 Watt) and sensitivity Spectrum and Technology used

Coverage of Different Bands

Signal Strength Measurements 2100

1800

900

Coverage Shrinks during high load

High Load

Low Load

2G (Rx Level), dBm -65 3G (RSCP), dBm -75 4G (RSRP), dBm -80

-71 -85 -90

-81 -95 -102

-95 -101 -110

No Network

Bad Outdoor

Technology (Cell Breathing effect in 3G)

-105 -105 -120

Coverage/Signal Strength Cont. Coverage Prediction  Banglalink use “Planet” tool for coverage prediction of different technologies  Planet Tool use Clutter Type, BTS & MS Sensitivity, BTS and MS Output Power, Antenna Height, Tilt, Azimuth, Technology, Services etc. for producing coverage prediction

2G

Outdoor Coverage (-95 dBm)

3G

Outdoor Coverage (-101 dBm)

4G

Outdoor Coverage (-110 dBm)

Quality of the Signal Quality Subscriber always rate a Network based on “Quality” of the Network. Network Quality is mainly depends on Signal Quality. If Signal Quality is poor then customer will experience poor voice and Data Performance and in some cases Call Dropped and Data Disconnections Quality of the signal is depends on below points    

Internal & External Interference Distance of the User from the Base Station (Signal Strength of the Serving BTS) Very High Load (Many User is using receiving service from the same BTS) Spectrum and Technology used (GSM 1800 Band’s Quality is good, 2G Quality < 3G Quality < 4G Quality)

Internal & External Interference

Distance of the User from Base Station

Quality Definition in 2G, 3G & 4G 0

0

0

1

-3 dB

-3 dB

2

-6dB

-6dB

-10dB

-9dB

5

-15dB

-12dB

6

-20dB

-13dB

Good Internal Interference from Adjacent BTS

3 Good Quality Service

External Interference from TV/Radio broadcasting tower

Poor Quality Medium Quality Service Service

4 Fair

Very High Load Poor

7 RxQual 2G

In very high load situation customer experience will be poor than normal load BTS

Ec/No 3G

RSRQ 4G

Capacity Capacity Every Network Nodes and Links has a certain capacity for Services. Reaching the maximum capacity results network failure, Service interruption, Blocked call, low internet speed etc. Based on utilization, upgradation have to be done. A “Threshold” (which is lower than maximum capacity) is set and if a network entity reach the “Threshold” then network planning team upgrade it. This “Threshold” is different for different Nodes/Links Core  Hardware  Software Version  Processing Power  Simultaneous User  PDP

BTS/NodeB/eNodeB  Hardware  Software Version  Power  Processing Power Transport Hub  Bandwidth  Port Capacity Optical  Bandwidth  Port Capacity

Maximum Capacity

100%

Internet GMSC

Node B

70% Threshold

Internet

Transport

RNC

GGSN

Node B

Air  Channels No.  Carrier No.  Total BW

Microwave  Bandwidth  Port Capacity

Interface  Bandwidth  Port Capacity RNC/BSC  Hardware  Software Version  Processing Power  Simultaneous User

Interface  Bandwidth  Port Capacity  IIG Capacity

0%

Terminology & Frequently Asked Questions Drop Call

Blocked Call

Low Throughput

Dropped call occurred when the Network “Signal strength” , “Quality” decreases or the network have any “Operational Issue” then the Network is unable to communicate to the UE. In this scenario the network releases the call.

Blocked call occurred when “Network has limited/No Capacity” or has any “Operational problem”. In this scenario the network blocks the call to maintain the Quality of the existing call.

Customer will experience low Throughput when Network has “limited/No Capacity”, “Poor Signal Strength and Quality” or has any “Operational problem”.

Mobile is in cell Edge

Signal strength and Quality is very poor

Network Blocked the Call due to High Load

Signal strength is good but Quality is very poor Network Blocked the Call due to operational issue like HW fault. In this case lots of call will be blocked Good Signal Strength and Quality but has operational issue like. HW fault. In this case lots of call will be dropped

Throughput is varied with the coverage and Quality. Cell edge customer will receive low where as the closer users will receive higher throughput

Voice Call Flow Mobile Terminating call Flow 1.

The incoming call is passed from the fixed network to the gateway MSC (GMSC) 2. Then, based on the IMSI numbers of the called party, its HLR is determined 3. The HLR checks for the existence of the called number. Then the relevant VLR is requested to provide a mobile station roaming number (MSRN) 4. This is transmitted back to the GMSC 5. Then the connection is switched through to the responsible MSC 6. Now the VLR is queried for the location range and reachability status of the mobile subscriber 7. If the MS is marked reachable, a radio call is enabled 8. and executed in all radio zones assigned to the VLR 9. When the mobile subscriber telephone responds to the page request from the current radio cell 10. all necessary security procedures are executed 11. If this is successful, the VLR indicates to the MSC 12. that the call can be completed

Voice Call Cont. Mobile Originating call Flow 1. 2. 3.

4. 5. 6.

The MS uses RACH to ask for a signaling channel The BSC/TRC allocates a signaling channel, using AGCH The MS sends a call set-up request via SDCCH to the MSC/VLR. Over SDCCH all signaling preceding a call takes place. This includes: • Marking the MS as “active” in the VLR • The authentication procedure • Start ciphering equipment identification • Sending the B-subscriber’s number to the network • Checking if the subscriber has the service “Barring of outgoing calls” activated The MSC/VLR instructs the BSC/TRC to allocate an idle TCH. The RBS and MS are told to tune to the TCH The MSC/VLR forwards the B–number to an exchange in the PSTN, which establishes a connection to the subscriber. If the B-subscriber answers, the connection is established

VoIP

Two Method for VoIP: Method 1:

VoIP Gateway serves to establish direct connection between GSM network and VoIP. Sim-card is put into GSM Gateway in order to register it with the GSM network, at the same time the gateway is connected with VoIP. Accordingly the communication (traffic / calls / SMS) can be converted in and out between GSM and VoIP channels. Method 2: Use mobile Application that use Packet Data for Voice Communication like WhatsApp, Viber, Skype

Roaming Roaming Process 

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The “Mobile User A” has an international roaming service with their “Home Operator” and is automatically connected to “Visited Operator A” while roaming. “Mobile User A” is automatically granted access to “Visited Operator A’s” network when arriving in the visited country by an exchange of a data between “Home Operator” and “Visited Operator A”, where “Visited Operator A” confirms Mobile User A is a roaming customer with “Home Operator” There should be roaming agreement between “Visited Operator A” and “Home Operator” specifies how this data is to be provided to the visited operator. “Mobile User A” pays a retail price to “Home Operator” for the roaming service and does not pay “Visited Operator A” “Mobile User B” is not also roaming, they will not incur any extra charges to receive a call from, or to make calls to “Mobile User A”. “Visited Operator A” sends transferred account procedure (TAP) files to a clearing house which forwards them to the “Home Operator”. TAP files are used for billing of calls while roaming. “Home Operator” can then pay “Visited Operator A” the wholesale charges as per call volumes in the TAP file and rates in the wholesale roaming agreement. “Visited Operator A” pays an “International carrier” for carrying the call and handing over the call to “Home Operator”. “International Carrier” pays “Home Operator” a termination rate for terminating the call in the home country

Brief description of BL Roaming Service International roaming service since inception has focused more on inbound roamers Since 2013 Banglalink is principally responsible for Retail Roaming – Outbound In addition Banglalink as a local OpCo provides full operational and strategy implementation support to VEON in achieving Wholesale Roaming KPIs Customers who use international roaming provides much higher revenue than non-roamers, In today’s competitive business scenario, acquiring potentially high revenue customers is very important and retaining them and keeping them satisfied is a must Banglalink recently launched Outbound Roaming for our prepaid subscribers Banglalink’s IR coverage currently stand at: GSM Roaming: 455 Operators in 165 Countries GPRS Roaming: 350 Operators in 121 Countries CAMEL Roaming: 108 Operators in 44 Countries

Current total Outbound roamers 3415 and average inbound roamers per day 30k – 35k

Radio, Health & Environment “Mobile Phone” and “BTS” radiates Electromagnetic Energy and often EMF is used to indicate the presence of electromagnetic radiation. ITU (International Telecommunication Union) has “EMF” Guideline and Standardization of “Human exposure guidelines”

The EMF guide and details can be reach through ITU website. Every mobile operator operate their services within the standardization parameter set by WHO & IEEE. Below is some important FAQ..  What are the effects of RF EMF?  Heating of tissues that leads to an increase in the body temperature This is known as the thermal effect. Although the body has its effective ways of regulating its temperature, nevertheless, if the RF exposures are too high, the body may no longer be able to cope.  What are the EMF levels around base stations?  Recent surveys have shown that RF exposures from BS range from 0.002% to 2% of the levels of international exposure guidelines, depending on a variety of factors such as the proximity to the antenna and the surrounding environment  Is it safe to live near a base station or locate base stations near schools or hospitals?  Yes. It is safe to live near a mobile phone base station as they operate at low power, produce low EMF exposure levels in public areas and are specifically designed for the environment they are located in.  "Studies to date provide no indication that environmental exposure to RF fields, such as from base stations, increases the risk of cancer or any other disease.“  Do more base stations reduce EMF?  Yes. As a matter of fact, by increasing the number of base stations and locating them near where people use mobile phones actually reduces EMF levels. This is because the mobile phones only need to transmit over a short distance to the nearest base station using less power, and the network is also operating more efficiently only needing to communicate with nearby users.  Are there restricted areas in front of base station antennas?  Yes. Base station antennas typically have an area directly in front of the antenna where the radio frequency field level will exceed the human exposure limits recommended by ICNIRP. These restricted areas are typically not accessible to the public as the base station antennas are mounted well clear of public areas.  Mobile network operators need to ensure that restricted areas around base stations are incorporated into the site design.

How we work?

Teams:

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Planning Strategy & Standardization BSS Planning Transport Planning Core Planning Radio Planning & Optimization Acquisition NI SOC NSS Operations Field Operations

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SA&E