Telecom Knowledge

Here we will discuss 2G/3G/4G/VoLTE & 5G/VoNR and IMS Initialย Knowledgeย of Testing Field.

๐Ÿ“we will discuss test case short definition and execution process.
๐Ÿ“Go through Short Question and Answer’s.ย 

  • These Knowledgeable Data we have Categorized in 3 types,ย 
    iBasic level (Question start with Green color, for example Q-1, Q-2, Q-3……)
    ii– Middle level (Question start with Yelllow color, for exampleย Q-1,ย Q-2,ย Q-3……)
    iiiAdvance level (Question start with Red color, for exampleย Q-1,ย Q-2,ย Q-3……)

๐Ÿ“: Short brief on Cellular Technology Evolution: From 1G to 5G ๐Ÿ“ถ
๐Ÿ“ฑ 1G (First Generation) ๐Ÿ“ž
Technology: Analog
Era: 1980s
Features: Basic voice calls ๐Ÿ—ฃ๏ธ
Example: Remember those brick-sized phones? They could only make and receive calls, but they paved the way for the future ๐Ÿงฑ๐Ÿ“ž

๐Ÿ“ฑ 2G (Second Generation)๐Ÿข 
Technology: GSM, CDMA
Era: Early 1990s
Features: Digital voice calls ๐Ÿ“ž, SMS text messaging ๐Ÿ’ฌ, and basic data services ๐Ÿ“ถ
Example: You could send a text message or make a voice call, but web browsing was slow and limited.

๐Ÿ“ฑ 3G (Third Generation) ๐ŸฆŠ
Technology: UMTS, HSPA
Era: Early 2000s
Features: Faster data speeds ๐Ÿš€, mobile internet ๐ŸŒ, video calling ๐Ÿ“น, and multimedia streaming ๐ŸŽต๐ŸŽฌExample: You could browse the web, check emails, and watch YouTube videos with improved speed and quality ๐Ÿ„โ€โ™‚๏ธ๐Ÿ“ฑ.

๐Ÿ“ฑ 4G (Fourth Generation) ๐Ÿฆ…
Technology: LTE, WiMAX
Era: Late 2000s
Features: High-speed mobile internet ๐ŸŒ๐Ÿ’จ, HD video streaming ๐ŸŽฌ, online gaming ๐ŸŽฎ, and improved voice quality (VoLTE) ๐Ÿ“ž
Example: You could stream Netflix movies or play online games with minimal buffering and latency โšก๐Ÿ“ฑ

๐Ÿ“ฑ 5G (Fifth Generation) ๐Ÿš€
Technology: 5G NR
Era: 2019
Features: Ultra-fast data speeds ๐ŸŒ๐ŸŽ๏ธ, lower latency โšก, massive IoT connectivity ๐ŸŒ, enhanced network capacity, and support for advanced applications like AR/VR ๐Ÿ•ถ๏ธ
Example: You could download large files in seconds, enjoy lag-free gaming, or experience immersive virtual reality ๐ŸŽข๐Ÿ“ฑ

๐Ÿ“Q-01: What is a role of Test Engineer in Telecom Testing Field…?
Ans: Test Engineer responsibility is execute test case and sort out the Issue to maintain Quality standard of product/modem/device.
๐Ÿ“Q-02: What is MNO’s….? (Mobile Network Operator)
Ans: Mobile Network Operator (MNO) is also known as wireless services provider, wireless carrier, Cellular Company or mobile network Carrier which provide wireless communication service that Own control all elements it’s Sell, billing, Customer care and deliver their best services to an end user.
As in Saudi Arabia have total 3 Operator.  i-STC, ii-Zain and  iii-Mobily
๐Ÿ“Q-03: What is MVNO’s….? (Mobile Virtual Network Operator)
Ans: “Mobile Virtual Network Operator (MVNO) is a communication services provider that does not use its own infrastructure to provide connectivity, but leases out infrastructure from other Network operator to offer a more competitive connectivity plan to an end user.”
As in Saudi Arabia have total 5 virtual Operator.  i-Salam(Zain) ii-Jawwy(STC)  iii-Frendy(STC) iv-Virgin(STC), and v-Lebara(Mobily)
For Detail study about Virtual Operator please visit below page..
๐Ÿ“Q-04: Explain all band (2G/3G/4G/5G) which Supported by MNO’s in your Country,
Ans: All Band information for Saudi Arabia is mentioned below.
                  NR/SNR Band——————LTE Band——————WCDMA Band——————GSM Band
n78 (3500 MHz)————–B1 (2100 MHz)——-B1 (2100 MHz)—————900 MHz
B3 (1800 MHz)
B28 (700 MHz)
Zain:      n78 (3500 MHz)————–B1 (2100 MHz)——-B1 (2100 MHz)—————900 MHz
B3 (1800 MHz)
B20 (800 MHz)
Mobily:  n78 (3500 MHz)————-B1 (2100 MHz)——- B1 (2100 MHz)—————900 MHz
B3 (1800 MHz)
B28 (700 MHz)
๐Ÿ“Q-05: What is RSRP, SINR, MCS, IBlER, PCI & SC, etcโ€ฆ.? 
Ans: These all are necessary RF parameter which UE getting from nearest serving Site/Station.
โœณ๏ธRSRP: (Reference Singal Received Power) It show the signal Strength of serving Site, 
Excelent RSRP Range is is -45 to -80db, and good is -80db to -90db and midd is -90 to 100 and below than -100db is bad.
โœณ๏ธSINR : (Signal interference to noise ratio) It measuring Signal Quality.
Excelent is Greater than 20db, and good si 13 to 20db, middle is 0 to 13, below o is Bad/Edge.
โœณ๏ธMCS: (Modulation Coding Scheme) mcs index is a number that indicate/measure the quality and max data rate of wifi connection between Station and User. 
โœณ๏ธiBler: (initial Block Error Rate) It show the block Data Ratio, which initially transmitted. and iBler ration should be around 10%.
โœณ๏ธPCI & SC: (Physical Cell ID) It show the physical identity of each Sertor/Cell. for 4G and 5G Used PCI. and in 3G used PSC (Physical Scrumbling Code).
๐Ÿ“Q-06: What is Sanity Testing…?
Ans: Sanity testing is a kind of Software Testing performed after receiving a software build, with minor changes in code, or functionality, to ascertain that the bugs have been fixed and no further Critical/blocker issues are introduced due to these changes.
In sanity Testing we are performing these important test Case with provided build to insure there’s no bug. As “Call, Data, SMS/MMS and IMS” function or other test case if requested.
๐Ÿ“Q-07: What is IMS…? (IP Multimedia Subsystem)
Ans: IMS stands for IP Multimedia Subsystem,  IMS is a standards-based architectural framework for delivering multimedia communications services such as voice, video and text messaging over IP networks.
>>IMS test case which we are performing as Volte/Vilte, Vowifi,Viwifi etc.
๐Ÿ“Q-08What is SRVCC..? How to perform..? (Single Radio Voice Call continuity)
๐Ÿ“Q-09What is CSFBโ€ฆ? (Circuit Switch Fall Back)
๐Ÿ“Q-10: What is VOLTE..? (Voice over LTE)

Ans: “VoLTE stands for Voice over LTE, VoLTE allows you to make and receive voice calls using the 4G network”
>>With volte makes your voice call more clear with high Quality. And during Volte call we can use Data on 4G network.
๐Ÿ“Q-11: What is Cell Reselectionโ€ฆ? 

Ans: “Cell Reselection happens only when the UE (or Mobile Phone) is in Idle MODE, and the UE needs to go a more appropriate cell”. 
“Itโ€™s a โ€˜wayโ€™ that UE uses to change the cell it is camped on, reselecting a โ€˜betterโ€™ cell”
For this UE follow’s this process: 
When the UE is turned ON, it makes a Cell Detection/Search, than a Cell Selection and finally completes de Registration, and stays in IDLE Mode.
๐Ÿ“Q-12What is IRAT Handoverโ€ฆ? 
Ans: “IRAT HO happens when the UE is in CONNECTED mode, mean The UE change its cell and goes to another cell; but in this case the UE has an active call (connection).”
In other way: it is the handover that happens among different RAT (Radio Access Technologies). So, IRAT HO stands for Inter Radio Access Technologies Handover. RAT can be either GSM, UMTS, LTE or any other wireless technology that is used by the UE.
๐Ÿ“Q-13: what is Redirection…….?
Ans: “Redirection mean when RRC connection completely released, and again re-Connect/latch on other or same frequency/technology it’s call redirection”. (in re-direction Service will Interrupted)
๐Ÿ“Q-14: What is handover…..? 
Ans: “Handover is also a connected mode procedure, when NW ask to UE latch from current serving cell to better prepare/target cell and network initiate handover” (During Handover service will not Interrupted).
๐Ÿ“Q-15: Handover types…..? 
Ans: we will discuss some handover types which usually happened during testing. 
๐Ÿ“žSimple handover and complex handover, 
>>In a “simple handover”, UE both cells are linked to the same switch (MSC).
>>while in a “complex handover”, UE both cells are connected to different switches.
๐Ÿ“žSoft handover and Hard handover. 
Soft Handover” mean UE first camp to the new Radio link and make a RRC connection then break existing Radio link. (This can also be simplified as make before break)
>>And “hard handover” mean UE first break existing Radio link Connection, and then make new Connection. (This can also be simplified as break before make)
๐Ÿ“žInter-eNB/Site handover and Intra-eNB/Site handover,
>>Inter-ENB handover” When a UE move from one sector to another neighbor eNB/Site sector this handover is call Inter-eNB handover.

>>”Intra-eNB handover” 
When a UE moves from one sector to another sector that is managed by the same eNB/Site, it’s called an Intra-eNB handover.
Note: For Other all types of Detail handover Process/Procedure, please visit below page.

๐Ÿ“Q-16What is CA (Carrier aggregation)โ€ฆ?
Ans: CA is a Feature used in LTE-Advanced  and 5G that allows mobile operator to combine two or more Carrier into single data channel to increase the capacity of the network and data rate.
๐Ÿ“Q-17If you are getting low TP what is the reason..?
Ans: There’s some possible reasion which can affect to TP (throughput).
1: Latency is High (mean ping value is too high)
2: Junction of serving site at same place, or front of particular site
3: Heavey Blockage
4: Trouble shooting of 2 or morethan 2 site at same time.
5: External Interference from Other Band or Network
6: Due to lot of user we can face effect on Throughput.
๐Ÿ“Q-18During FT if Call drop, what will be the possible reasonโ€ฆ.?

Ans: If Call drop there will be some reason, 
1: Handover Failure (or handover not define properely from RF Side)
2: Poor Coverage mean RSRP is very bad -105db to -120db.
3: If there is Heavy Blockage, (Building Blockage or Blockage infront of antena/sector)
4: Trouble shooting of different site in one place.
5: MOS (mean Opinion Score, which measure Call quality) is very bad like 1 or 2
๐Ÿ“Q-19What SS (Supplimentary Services)โ€ฆ? 

Ans: Supplimentary Services is UE Call Function which we need to test during Sanity testing, 
1: Call Forwarding 
2: Call waiting 
3: Call Barring
4: Voice mail call

๐Ÿ“Q-20: When you Receive new Device/Equipment/Tool/DUT/Auxilary then what will do, explain all steps from start to end..?

Ans: when Received new device for testing follow these steps.
1: First Take NV backup data and save in PC
2: Remove existing Xiaomi/Nokia/Huawei/Vivo and gmail account if logged-in.
3: Flash with required version, and complete first boot up process. It should normal
4: Now perform a Sanity Test (like Call, Data, SMS/MMS and SS)
5: Now do a Stress tesing, and try to Crash modem. (Stress testing mean Download heave data, upload data, Toogle APM on/off again and again, do these all steps quickly and same time.)
6: If above all things is Normal then move to Field test and start testing as per requirement.

๐Ÿ“Q-21: When you go to field which type of testing perfom..?
Ans: When Go to field need to perform these test, and follow test case Scanario.
1: Open google map check GPS getting correct location, lattitude and logitude is Correct.
2: Initiate a call and make Handover between Site to Site and Sector to Sector, mean intra and inter boht handover.
3: Make reselection 4G to 3G and 3G to 4G, perform IRAT dedicated mode.
4: Prform CSFB call and volte call test, Short call and long call as per requirement.
5: Perform SRVCC Test.
5: Make a call one by one with all RAT 2G/3G/4G and check Call noice is ok. Call handover is proper done.
6: Download huge file and then drive and observe when handover Done, Data should not drop or Stuck.
7: Check Vowifi Call and try to make handover Vowifi call to VOLTE call, and VOlte call to Vowifi ca