Interview Questions.

Question 1. What Is Wimax Technology?

Answer :

WiMAX Technology is an IP primarily based, wireless broadband access technology that gives overall performance much like 802.11/Wi-Fi networks with the insurance and QOS (nice of service) of cell networks. WiMAX is also an acronym which means "Worldwide Interoperability for Microwave Access (WiMAX).

Question 2. How Wimax Works?

Answer :

WiMax combines the advantages of preferred Wi-Fi and a huge insurance of cellular network. It takes a fine a part of wi-fi networks, the fast pace and broadband internet enjoy. WiMax is a WAN technology, provider providers will deploy a wimax network that permits access over lengthy distance. Coverage for a geographical location is split into a series of overlapping regions referred to as cells. Each cell provides insurance for users inside that on the spot location. When you journey from one cell to some other, the wi-fi connection is passed off from one cell to another.

 

Networking Interview Questions
Question three. What Is Base Station In Wimax System?

Answer :

The crucial radio transmitter/receiver mounted via provider provider to broadcasts WiMax signals. These transmitters are generally set up on towers or tall homes. Cellular networks are based totally on the concept of cells (a logical division of geographical vicinity), each such cell is allotted a frequency and is served by using a base station. 
Base station consists of a receiver, transmitter and a manage unit. Adjacent base stations use distinctive frequencies to keep away from move-communicate.

 

Question four. What Is Wimax Network Entry Procedure?

Answer :

The system facilitates wimax subscriber camp on to wimax compliant base station. Following are the summarized steps for network access. Please be aware that this manner is as according to IEEE 802.Sixteen-2004 OFDM PHY and MAC layer specifications. This version of wimax is likewise referred as fixed wimax because of non-mobility of subscriber stations. The method for mobile version of wimax i.E. Cellular wimax is much like this however there are few changes to MAPs/channel descriptors and header format in addition to addition in MAC messages.

Networking Tutorial
Question five. Define Raging Procedure In Wimax System?

Answer :

In wimax gadget, ranging system is initiated by means of SS(Subscriber Station) to set up connection with BS(Base Station). This ranging technique are of many types mainly available for synchronization and maintenance of RF link. After Ranging is finished Base station waits for SBC REQ message transmitted with the aid of the Wimax SS. Using SBC REQ message SS informs BS of its simple abilities. Unlike ranging request(RNG REQ) there may be no committed slot for bandwidth request and SBC REQ. Bandwidth request may be transmitted any in which inside the uplink subframe except the reserved ranging slot.

Android Interview Questions
Question 6. What Does Wimax Support For Encryption?

Answer :

WiMAX helps the following for encryption:

Advanced encryption popular
Triple statistics encryption general
 

Question 7. Which Modulation Schemes Are Supported By Wimax?

Answer :

The following modulation schemes are supported via WiMAX:
? Binary segment shift keying modulation
? Quadrature segment shift keying modulation
? Quadrature amplitude modulation

 

Android Tutorial OBIEE Interview Questions
Question 8. What Frequencies Are Used By Wimax Networks?

Answer :

Standards does no longer outline any uniform global licensed spectrum for WiMax, however the WiMax discussion board has posted 3 licensed spectrum profiles 2.Three GHz, 2.Five GHz and three.5 GHz, as a way to pressure standardization and reduce fee. Also plans for use of analog TV spectrum (seven hundred MHz) look ahead to the complete deployment of digital TV.

 

Question nine. Please Specify Wimax Is Secure Or Not?

Answer :

Yes, WiMax is a widespread based design, and WiMax standards are nicely defined to provide plenty better and bendy protection than wireless networks. 
? WiMax safety stack helps two encryption standards one is famous DES3 (Data Encryption Standard) and other is AES (Advanced Encryption Standard). 
? Additionally it requires devoted safety processor for base station.
? It also defines minimum encryption necessities for the site visitors and for cease to stop authentication.

Mac OS X Deployment Interview Questions
Question 10. Why Do We Need Wimax Technology?

Answer :

We need WiMAX technology for high speed broadband like net get admission to on the move. We have broadband connections that offer high pace networks, however are connected to LAN systems i.E. No longer transportable. Wi-fi offers access to such systems however restricted to a far shorter distance. 
Then we've cellular networks which offer internet get right of entry to however their pace is restricted and they're exceedingly costly. To overcome these troubles we need WiMax or comparable technology.

OBIEE Tutorial
Question 11. What Are The Limitations Of Wimax?

Answer :

WiMax cannot provide maximum overall performance over 50 kilometers. As the gap increases, bit errors charge for that reason lowering performance. Reducing distance to much less than 1km permits a tool to function at higher bit charge. A person in the direction of base station gets better speed at round 30 mbps.
Also as an available bandwidth is shared between no of users, performance relies upon on number of active customers connecting to that base station. So this desires a use of Quality of Service (QOS) mechanism to provide a minimum assured throughput.

 

GSM Interview Questions
Question 12. What Is The Difference Between Cid And Sfid In Wimax System?

Answer :

A carrier flow in wimax is partially characterised by the subsequent attributes:
? A 32-bit Service Flow ID (SFID) is assigned to all present provider flows. The SFID serves as the important identifier for the Service Flow and has an associated path.
? A 16-bit Connection ID (CID) is associated with each energetic SFID (connection active).
? A set of QoS parameters specifying the required sources. The major useful resource is bandwidth, however the specification may also include latency necessities.
? A set of QoS parameters defining the extent of carrier being furnished.

Networking Interview Questions
Question thirteen. What Is A Wimax Gateway?

Answer :

It is a stand by myself indoor tool that is mounted at a good reception place. It acts as a wireless access point for other devices such as domestic pc, VOIP handset and so forth. WiMax operators normally offer this gateway device or subscriber unit which communicates with base station and gives wi-fi access within domestic or workplace for tool like computer, Smartphone.

GSM Tutorial
Question 14. Define Be Class In Wimax Qos?

Answer :

In this class, BW is granted to mobile subscriber if and simplest there could be left over bandwidth from different QoS training. This QoS magnificence guarantess neither put off nor throughput. It allows minimal reserved site visitors price and maximum sustained site visitors fee.

 

Question 15. Define Ertps Class In Wimax Qos?

Answer :

This QoS kind is developed to support VOIP together with silence suppression. There will be no visitors transmission during silence time. QoS parameters are equal as UGS kind. Check table-1 for utility of this type. ErtPS is much like UGS wherein base station assigns MST on lively mode and no BW is allotted for the duration of silent time period. Here BS need to ballot  cellular subscriber to understand whether silent duration has been ended or it's miles persevering with.

Wireless Interview Questions
Question sixteen. Define Rtps Class In Wimax Qos?

Answer :

It is used for VBR real time visitors as an instance MPEG video. Unlike UGS in which in constant allocation is made through BS, right here BS frequently polls MS to find out allocation need. Hence bandwidth is allotted on need foundation and is adaptive in nature. For this wimax QoS kind Min. Reserved site visitors rate and MST need to be cited one by one. For UGS and ertPS Min. Reserved visitors rate and MST are both identical. QoS parameters are same as UGS.

IMS/DB Tutorial
Question 17. Define Ugs Class In Wimax Qos?

Answer :

This Wimax QoS class offers constant bandwidth allocation on periodic basis. Once the connectivity is installed, no greater requests are wished. For utility of this type. QoS parameters for this kind are MST, tolerated jitter and max. Latency.

LAN Interview Questions
Question 18. What Are The Wimax Qos Classes?

Answer :

Following are the WiMAX QoS training:
? UGS
? rtPS
? ertPS
? nrtPS
? BE

Android Interview Questions
Question 19. What Is The Difference Between Wimax And Lte?

Answer :

Both WiMAX and LTE are used for supplying broadband wi-fi internet offerings.
WiMAX is the absolutely new wellknown developed for providing high facts fee net offerings. WiMAX is designed for most effective statistics packages. As it is totally new era with none legacy guide,it is very high-priced and calls for service company to put in all the equipments.
LTE follow mobile standards including HSPA,WCDMA,GSM and so on however it is designed especially for statistics applications. It is likewise referred as all IP information network. Voice over LTE is likewise viable the use of legacy fall backs and the usage of VOIP protocols. Due to predecessors present equipments may be make use of and for this reason it's far less steeply-priced and calls for minimal preliminary investment.

 

SIP Tutorial
Question 20. Give An Example Of Wimax Tlv Format?

Answer :

EXAMPLE:
FEC code kind for downlink burst
150(0x96), 0x01(msb:0),0x01(QPSK 1/2) 
? Here first byte is kind.
? As value is less than 127 period field in second byte is one byte with msb set to zero and its final 7 bytes shows that size of price subject is one(1).
? The value field is mentioned as 0x01 representing as QPSK half of modulation-code fee.
If the size of 'cost' field is more than 127 bytes(>127) then 
? Size of length area will be one byte extra than what is definitely used to say length of 'price' discipline in bytes. 
? MSB of first byte of 'length' discipline is about to at least one 
? The ultimate 7 bits of first byte of 'period' discipline shows extra bytes of 'period' area 
? The bytes apart from first byte of 'duration subject' is used to mention size of the 'value discipline'.

Network Administrator Interview Questions
Question 21. What Are The Rules Apply For Wimax Tlv Encoding Format?

Answer :

Following guidelines follow for this. Size of price discipline depends on period field unique.
If the real length of 'cost' subject is less than or same to 127 bytes(length<=127) then 
? Size of 'duration' area may be 1 byte 
? MSB of 'period' discipline is about to 0 
? The relaxation of seven bits of length subject suggests real size of 'value' discipline in wide variety of bytes.

Question 22. What Is Wimax Tlv Encoding Format?

Answer :

In wimax TLV codecs are used for parameters in each mac management messages as properly configuration report. TLV stands for Type, duration and price. Size of kind field could be usually 1 byte. Size of period subject is both 1 byte or more than 1 byte.

Question 23. Do You Know What Is Wimax Fch/dlfp?

Answer :

The modulation-code charge of wimax FCH or DLFP is constant to BPSK-half. It has overall length of approximately 88 bits as mentioned under.
WiMAX FCH/DLFP:  BS ID(4 bits), Frame No.(four bits), CCC(four bits), Reserved(4 bits), 
Rate ID(four bits), Preamble(1bit), Length(eleven bits), DIUC(4bits), Preamble(1bit), Length(eleven bits),
DIUC(4bits), Preamble(1bit), Length(11 bits), DIUC(4bits), Preamble(1bit), Length(11 bits),
HCS(8 bits)

4G Interview Questions
Question 24. What Are The Basics Of Fch Or Dlfp In Wimax System?

Answer :

As we realize wimax frame includes downlink subsubframe and uplink subframe. Downlink Subframe includes preamble(2 OFDM symbols), header, downlink bursts(1, 2, 3 or four). After downlink subframe, uplink subframe starts with a few hole used for TTG and rivalry slots. The transmissions from BS to SSs is referred as downlink and transmissions from SSs to BS is referred as uplink subframe. Header cited above is known ad FCH (Frame Control Header) or DLFP (Downlink Frame Prefix). On this web page we are able to see header used in constant wimax as consistent with OFDM specifications for 256 factor FFT.

OBIEE Interview Questions
Question 25. What Are Basics Of Fch Or Dlfp In Wimax System?

Answer :

As we understand wimax frame includes downlink subsubframe and uplink subframe. Downlink Subframe consists of preamble(2 OFDM symbols), header, downlink bursts(1, 2, 3 or four). After downlink subframe, uplink subframe starts with some gap used for TTG and competition slots. The transmissions from BS to SSs is referred as downlink and transmissions from SSs to BS is referred as uplink subframe. Header referred to above is known advert FCH (Frame Control Header) or DLFP (Downlink Frame Prefix). On this web page we are able to see header used in constant wimax as consistent with OFDM specs for 256 factor FFT.

Question 26. What Is The Difference Between Siso And Mimo Techniques In Wimax?

Answer :

These are strategies based on range of antennas used at the transmitter and the receiver. SISO has been in use for the reason that invention of wireless system. MIMO concept has been recently brought to the wireless system. There are extraordinary MIMO algorithms which has been developed for two primary motives to growth insurance and to growth the data rates.
SISO means Single Input Single Output at the same time as MIMO way Multiple Input Multiple Output.
In SISO machine simplest one antenna is used at transmitter and one antenna is used at Receiver while in MIMO case multiple antennas are used. Figure depicts 2x2 MIMO case.
MIMO system achieves higher Bit Error fee evaluate to SISO counterpart on the equal SNR. This is performed using approach referred to as STBC (Space Time Block Coding). With STBC coverage can be better.
MIMO system can provide higher records price because of transmission of more than one records symbols simultaneously the use of multiple antennas, this method is referred to as as Spatial Multiplexing (SM). With SM statistics rate may be greater.
MIMO with SM and beamforming may be hired to obtain enhancement to each the insurance and records charge requirement in a wireless device.
SISO is utilized in radio, satellite, GSM and CDMA systems whilst MIMO is utilized in subsequent era wi-fi technologies which includes mobile wimax -16e, WLAN-11n.11ac,11ad, 3GPP LTE and so on.

IMS/DB Interview Questions
Question 27. What Is The Difference Between Micro Controller And Microprocessor In Wimax?

Answer :

                    Microcontroller typically operates at frequencies in MHz variety whilst contemporary Microprocessor operates in GHz frequency range. This clock is provided the usage of oscillator. Microcontroller and microprocessor each have their personal applications. Hence each cannot be used for each different's purposeful areas besides for few exceptions (very low size code/statistics application).
                    In addition to microprocessor (CPU) functionality microcontroller can have timers, counters, RAM, ROM and Input/Output ports. Most of the microprocessors have Op-codes for moving data from the external reminiscence to the CPU; Microcontrollers may have one or . Microprocessors have one/ types of bit managing commands while Micro controllers have many. Microprocessor is used for trendy purpose packages even as microcontroller is program precise and designed for precise application in attention.

Mac OS X Deployment Interview Questions
Question 28. What Is Bw Req Header In Wimax?

Answer :

BW REQ Header requests check with the mechanism that SSs use to indicate to the BS that they want uplink BW allocation. Because the uplink burst profile can alternate dynamically, all requests for BW will be made in phrases of the quantity of bytes needed to deliver the MAC Header and payload however now not the PHY overhead. BW REQ message may be transmitted all through any uplink allocation, except during any preliminary ranging c program languageperiod. BW is usually requested on a CID foundation and BW is allocated on an SS basis.

Question 29. What Is The Difference Between Fdm And Tdm In Wimax?

Answer :

? TDM is hired in PCM transmission to attain T1 on the charge of one.544Mbps. 
? FDM is employed in satellite,Radio,HF and different wireless technologies. 
? Both TDM and FDM is hired in GSM mobile era.

3G Interview Questions
Question 30. What Is Fdm And Tdm In Wimax?

Answer :

FDM is the fast shape of frequency division multiplexing and TDM is the short shape of time department multiplexing.

 

Question 31. What Are The Advantages Of Ofdm In Wimax?

Answer :

? Frequency selective fading might be capable of affect few of the subchannels/subcarriers and no longer entire band.
? OFDM overcomes impact of ISI occuring by and large in multipath channel surroundings.

Question 32. What Is The Difference Between Sc-fdma And Ofdm Modulation Techniques In Wimax?

Answer :

? SC-FDMA way Single Carrier Frequency Division Multiple Access and OFDM approach Orthogonal Frequency Division Multiplexing.
? SC-FDMA gadget generally may have low PAPR examine to OFDM machine.
? SC-FDMA machine is much less touchy to frequency offset examine to OFDM system.
? SC-FDMA is broadly used in LTE subscriber terminals in the transmit route and its version OFDMA is used in the eNodeB downlink(or acquire direction of LTE subscribers).
? OFDM is used in many broadband technology including wimax-16d/16e, WLAN-11a/11n/11ac.
?OFDM is referred as multicarrier modulation.
? It makes use of more than one rf service signals at exclusive frequencies which sends a number of the bits on each of the assigned channels. This seems to be much like FDM but inside the case of OFDM, overall subcarriers are divided into subchannels and these subchannels are mapped to 1 unmarried records/visitors supply.

Transport Layer Security Interview Questions
Question 33. What Is The Advantage And Disadvantage Of Using Qam Modulation Over Qpsk?

Answer :

QAM entails both amplitude and segment version to map the digital records over the subcarriers. QPSK entails only phase variant while amplitude remains constant. 16QAM for instance maps four bits of statistics on one single provider and QPSK maps 2 bits of statistics on one single carrier. Hence 16QAM help growth information charge over QPSK but receiver turns into complex so one can retrieve the modulated symbols if it's far exceeded through the noisy channel surroundings.

GSM Interview Questions
Question 34. What Is Rng Req In Wimax?

Answer :

RNG REQ is transmitted through SS to BS. After appearing Synchronization (Time, Freq, Channel) RNG REQ Frame is decoded to bits at BS. Type subject simply after GMH will describe message type that's '0x04' for RNG REQ, which tells BS what want to be performed after receiving the message.

Question 35. What Will Be Analysed With Rng Rsp Decoded By Ss In Wimax?

Answer :

RNG RSP decoded by SS will analyze following:
? 'Timing Adjust' area (signed 32 bit) and could pressure PHY to advance body Transmission accordingly.
? 'Power stage Adjust' field (signed eight-bit, 0.25dB) and will drive RF attenuators at RF layer as a consequence.
? 'Offset Frequency Adjust' area (signed 32 bit, Hz gadgets) and could pressure RF synthesizer/Ref. OCXO therefore.
? Ranging Status (if repute is 're variety') will imply whether SS want to do retransmit RNG REQ or (if popularity is 'Success') begin BW REQ transmission for figuring out slot for SBC REQ.

Question 36. What Is The Unit Of Resource Allocation In Mobile Wimax I.E Ofdma System?

Answer :

The unit of resource allocation in cellular wimax (OFDMA) is slot. The slot definition varies based on zone type. There are one-of-a-kind zones supported inside the cellular wimax frame. The most not unusual used area kinds are PUSC, FUSC and AMC. In the uplink PUSC and AMC are used.
In downlink PUSC, slot is 1 sub-channel X 2 symbols 
In Uplink PUSC, slot is 1 sub-channel X 3 symbols
In downlink FUSC, slot is 1 sub-channel X 1 image
AMC is two symbols X 3 sub-channels.

Wireless Interview Questions
Question 37. What Are The Wimax Ranging Procedures?

Answer :

There are numerous wimax ranging approaches as mentioned below.
? Initial Ranging
? Periodic Ranging
? Contention Ranging
? Non-Contention Ranging

 

Question 38. What Is Non-competition Raging Procedure In Wimax?

Answer :

Non-contention raging is regulated by means of the BS to permit the SS to finish device get admission to in advance when dedicated channel is provided and polled preliminary ranging.

Question 39. What Is Contention Raging Procedure In Wimax?

Answer :

Contention raging manner is required via the SS to get entry to the system for the primary time and no committed connection resources assigned to the SS.

Question forty. What Is Periodic Raging Procedure In Wimax?

Answer :

Periodic raging is to hold uplink conversation with the BS and to alter transmission parameters.

LAN Interview Questions
Question forty one. What Is Initial Raging Procedure In Wimax?

Answer :

Initial raging acquires accurate transmission parameters (Power adjustment, timing offset estimation and synchronization) to communicate with the BS.

Question forty two. What Is The Difference Between Wimax System And Lte System?

Answer :

WiMAX and LTE both are used for imparting broadband net get right of entry to offerings. Voice services are also planned to provide over wimax and LTE networks the use of Voice over IP protocols. WiMAX stands for World Wide Interoperability for Microwave Access and LTE stands for Long Term Evolution. WiMAX fall back to non-cell technology consisting of WLAN. LTE fall lower back to cell technology including GSM, UMTS etc. In wimax both uplink and downlink use symmetric modulation schemes together with OFDM or OFDMA. In LTE downlink uses OFDMA and uplink uses SC-FDMA.

Network Administrator Interview Questions
Question forty three. What Is The Difference Between Tdd And Fdd In Wimax?

Answer :

Both TDD and FDD are duplexing topologies used in particular to share the not unusual imperative assets. In TDD, frequency is shared amongst subscribers time slot sensible. In FDD, one pair of frequency is assigned for one connection one for downlink and one for uplink and subsequently transmission will happen concurrently in both the guidelines.

Question 44. How Is The Data Rate Calculated In Fixed Wimax Based On Ofdm Physical Layer?

Answer :

Data rate is the charge at which information is transmitted over the air and is measured in Mbps.
Raw records price = Nsc * bm * Cr /Ts;
Where Nsc is the variety of facts subcarriers(here 192 for OFDM),
bm is coded bits in keeping with sub-providers
Cr is ratio of input bits to output coded bits
Ts is the symbol duration 
For BPSK half of, Maximum information charge could be (192*1*half)/(eleven.Eight microsec) = eight.Thirteen Mbps.
For 64QAM 3/four, Maximum information rate might be (192 * 6 * three/four)/(11.8) =seventy three.2 Mbps.

Question 45. Explain Wimax Frame Structure And Various Mac Fields Such As Dlmap, Dcd, Ulmap And Ucd And Their Significance?

Answer :

In order to apprehend wimax body shape interviewee need to understand and give an explanation for body structure of both OFDM and OFDMA physical layers. Basic OFDM wimax frame consists of preamble part, header component (FCH) and downlink bursts (1 to 4). Preamble is used for synchronization reason. FCH is always BPSK1/2 and carry modulation-code fee records of consecutive downlink bursts in addition to their lengths in quantity of symbols. Downlink burst no.1 convey DLMAP, DCD, ULMAP, UCD. DLMAP and ULMAP specify the position of downlink bursts and uplink bursts in the whole wimax frame. DCD and UCD specify downlink channel descriptor and uplink channel descriptor which in flip map to modulation-code price for the bursts i.E DIUC and UIUC.