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Qualcomm Firmware Engineer Interview Questions

12 Interview Reviews

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  1.  

    Modem Firmware Engineer Interview

    Anonymous Interview Candidate
    Anonymous Interview Candidate
    Application Details

    I applied online. The process took 4 weeksinterviewed at Qualcomm in December 2013.

    Interview Details

    First had a phone interview where I was invited to an onsite interview. There were 5 interviews in person with a lunch. Mostly asking about coding and brain teaser problem solving. There was also an interview with HR about desired salary. Didn't hear back from HR for over 2 weeks and had to contact them myself.

    Interview Questions
    • Everything about coding: structs, definitions, bit-wize, optimization   Answer Question
    No Offer
    Difficult Interview
  2. 16 people found this helpful  

    Modem Firmware Test Engineer Interview

    Anonymous Interview Candidate in San Diego, CA
    Anonymous Interview Candidate in San Diego, CA
    Application Details

    I applied online. The process took 2+ monthsinterviewed at Qualcomm in February 2013.

    Interview Details

    Telephonic Interview: Initially you will get an email from concerned Staffing team regarding the telephonic interview. Depending on your availability you can schedule an interview within the next week.

    Onsite: If you did good job on your telephonic call, you will be intimated about the onsite interview within the next 2 weeks. Again, if you get selected for onsite, the scheduling process will be the same as Telephonic.

    Interview Questions
    • Most questions would be based on your resume. They will concetrate what you did and not what they did :). So, please know in & out about your resume. Also, Please do not stuff your resume just for the sake of getting an interview call. Even if it did, it may be an issue if you did not answer their question on that topic. It is better to put stuff on which you are confident. For me, most of my telephonic interview had questions from Wireless Communications, Digital Communications, Random Signal Theory(Not in depth, for ex: How is a wireless channel distributed? why is it distributed like that? How does it's auto-correlation looks like? what are the other models available?

      Suggestions: Be good in Wireless Communications: Multipath, Coherence time, coherence bandwidth, time diversity, receiver diversity, doppler spread, WSS-US model, Rayleigh Fading, Rician Fading, Diversity schemes, Equalizers, OFDM, and the projects related to it. Digital Communication: Modulation schemes, BER, Basic Communication block diagram, etc.

      Last, but not least, in all these interviews there is no one-on-one answer. So, knowing the definitions related to this topics will not help. Try to related and study.

      A simple question, I would like to quote here, to say, how will their expectation be like. For

      Ex: Compare OFDM and CDMA. Hint you have is: With Shannon's channel thm, try to explain this. So, the interviewer is expecting you to apply a concept to two different technologies.

      Ex: Next question: How OFDM mitigates ISI? How CDMA mititgates ISI. (You must give an in-depth idea)

      Ex: Match Filters. How CDMA uses it. (Please go through match filter in-depth. This idea is used in CDMA Rake Reception. Please know, how it is getting used there. Also, Match filtering, is a kind of process that you can use for Channel estimation.

      Knowing the call processing procedure for any technology will also help. Please ,be sure with atleast one technology in depth.

      Last Suggestion: When the interviewer asks a question on a topic that you know well, start answering him that question with depth, so that your further questions will be based on it. So, this is like driving interviewer to an area that you are familiar. Else, it will be like he is trying to ask you different questions to know what you know.

      Best!
        Answer Question
    Accepted Offer
    Difficult Interview
  3.  

    DSP Firmware Engineer Interview

    Anonymous Interview Candidate
    Anonymous Interview Candidate
    Application Details

    I applied online. The process took 5 daysinterviewed at Qualcomm in March 2013.

    Interview Details

    I had a phone interview . I was expecting a detailed questionnaire on my projects but the interviewer started out with questions on C and then went on to ask questions related to DSP and Communications theory. The interviewer was good and was very patient in asking each question and listening to my answers.

    Interview Questions
    • Most difficult part for me were questions on C which i did not prepare at all. There were questions related to embedded systems and questions on Cache memory.   Answer Question
    No Offer
    Average Interview
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  5.  

    Modem Firmware Engineer Interview

    Anonymous Interview Candidate
    Anonymous Interview Candidate
    Application Details

    I applied online. The process took 4+ weeksinterviewed at Qualcomm in February 2013.

    Interview Details

    Applied online and got an email for phone interview invitation the next day. Phone interview was scheduled through email. Got response for phone interview after 3 days and an onsite interview was scheduled roughly 2 weeks from phone interview. Got final response 2 weeks after the onsite interview.

    Interview Questions
    • Write a assembly program for 32 bit multiplication.
      Others are expect. A C program and basic question in signal processing and communications.
        Answer Question
    Accepted Offer
    Average Interview
  6.  

    DSP Firmware Engineer Interview

    Anonymous Interview Candidate in Santa Clara, CA
    Anonymous Interview Candidate in Santa Clara, CA
    Application Details

    I applied online. The process took 4+ weeksinterviewed at Qualcomm in January 2013.

    Interview Details

    Applied on their career website. First was the phone interview where they asked about my projects and some basic questions. Called onsite at Santa Clara where i had 6 interviews.

    Interview Questions
    • questions were pretty simple like create a linked list of n nodes, some puzzles   Answer Question
    No Offer
    Neutral Experience
    Average Interview
  7.  

    Firmware Engineer Interview

    Anonymous Interview Candidate in San Diego, CA
    Anonymous Interview Candidate in San Diego, CA
    Application Details

    I applied through a staffing agency. The process took a weekinterviewed at Qualcomm in October 2011.

    Interview Details

    Phone Interview -
    Was asked computer architecture questions about bit handling and manipulation,
    About previous experience,
    And about school projects.

    Interviewer walked me through one of the puzzle questions, which I thought was unusual, but kind.
    Interviewer also described the position in exact detail, to avoid confusion.
    Felt fairly confident after the interview, as I answered every question.

    Interview Questions
    Accepted Offer
    Neutral Experience
    Average Interview
  8. 19 people found this helpful  

    Firmware Engineer Interview

    Anonymous Interview Candidate in San Diego, CA
    Anonymous Interview Candidate in San Diego, CA
    Application Details

    I applied online. The process took 4 weeksinterviewed at Qualcomm in February 2011.

    Interview Details

    Overall Qualcomm is very organized. And Very professional

    Interview Process:
    Applied Online
    After about two weeks HR e-mail me to set-up phone interview. Then I had a phone interview on same day.

    During Phone interview key question I asked is "do you have any concerns about me?" He told me he wants some body committed to position at least two years. Also He told me he will set me up for onsite interview.

    After another week HR e-mail me for on site interview.
    On site is with 1 HR and 5 Engineers on same department

    HR Will ask you how much money you made in previous job. Why you want to quit the job (I was currently employed), why you want to work @ Qualcomm, your future goals...

    Then the fun starts with the five engineers.

    Each interview takes about an hour. Lunch is also an interview.

    Each interviewer is very professional; however they will test you until you break to see how you handle. Based on my experience they're not testing to see if you know everything, it's more of testing your personality, and how your problem solving skills.

    My advice is making sure you know every word you on your resume. If you don't know the answer or don’t understand the questions, ask them questions. They were in our seat long time ago. They know what we going thru. Don’t give vague response that doesn’t really answer the question. They’re looking for short answers with the correct keywords. Not an essay answers.
    Before ending the interview make sure they can tell what are your strong points and weak points.
    Don't feel bad if you lose confidence after interview. That's normal for Qualcomm interviews. It’s like the last day of finals. You will be burned out by end of day.

    Good thing is 90% of questions will be based on what you put on your resume, while 10% will be problem solving skills.

    After onsite interview in two weeks HR called me saying “Congratulation and they will contact people I put as reference” That mean pretty much you got the job. Unless your reference don’t give good recommendation
    Then about week later HR will wants a copy of your degree. That’s it. After that you get an offer?.
    They don’t really have much room to negotiate. Initial offer is very competitive and attractive.

    One of the things I did is I wrote thank you letter after phone interview and onsite interview. I only knew HR e-mail. So I wrote to the e-mail to HR but I addressed everyone. You should do that too. I am not sure if it helps, but it certainly doesn’t hurt.

    Interview Questions
    • Programming Related:

      * what is the keyword volatile, static, const do?
      * where do static data reside in memory?
      * What are some ways to pass data into a function? and what the advantage and disadvantages?

      O/S Related
      * What makes an OS real time?
      * Difference between Semaphore, Mutex, and spin locks?
      * What is priority inversion, and what are methods to avoid it?
      * If processor has a FP unit, is it ok to use FP inside kerenel? why/why not?
      * What is is the difference between Non-blocking vs blocking calls? What are the benefits of each?
      * How would you execute a non-blocking call in kernel?

      Debuggin Related:

      * What is stack trace?
      * What data get pushed into a stack when jumping into a function call?
      * Give some example you would use a scope to trouble shoot software problem? What line would you use to trigger the scope?

      I/O Interface Related:

      * Explain UART communication protocol?
      * What signals are connected to DB9 connector, and how are they beeing used?
      * What are some ways UART could have communication error?
      * Explain I2C Communication protocol. How the Start, Stop condition generated? How do you select which device to communicate when all the devices tight to gether?
      * Explain SPI Communications.
        Answer Question
    • Programms to Write:

      * Find what's wrong with this function?

      void copydata(uint8_t *datato, uint8_t *datafrom, int size)
      {
      uint8_t *CurrentAddress = datafrom;
      uint8_t *StopAddress = datafrom + size;

      for(;CurrentAddress <= StopAddress;CurrentAddress++)
      *CurrentAddress = *datafrom++;

      }

      * Write algorithm to find missing element in array. For example

      int array[5] = {1, 2, 0, 3, 4};

      this array should contain # from 1 to 5. # 5 is missing.

      * find a element in array size of n using binary search method.

      * Write a small program that add element into linked list at beginning of the list, and back of the list?

      * Swap the bit order in a byte (example bit 7 would goto bit 0, bit 0 would goto bit 1)

      * Write a small test program that would test the read/write memory? What good value to write if you want to test if there two data lines tight together?
        Answer Question
    • Puzzles 1:

      You have rope that take 60 min to burn. Speed of burning is not uniform. Example: it doesn't take 30 min to burn half

      Using two ropes, how would you get 45 min?

      Answer:

      First Rope. Burn both ends at same time
      Second Rope: Burn only one side.

      when First rope is totally burn, it's been 30 min, now burn the rest of second rope both ends. Which should take additional 15 min.

      30 + 15 = 45 min.

      Puzzle 2:

      There is a guy in a boat holding a rope that's tight to a Top of pole in the shore. He keep pulling the rope until he reach the shore. What is the speed relationship between amount of rope he pulls, vs horizonal speed? Which speed is higher?

      Answer:

      Horizonal speed is faster than the amount of rope he pulls. (Horizonal distance he travel is higher than amount of rope he pulls, by triangle theory where sum of two sides must be greater than 3rd side)

      Puzzle 3:

      in Analog Clock, It's exacly 3:00 Clock. What time would the Hour hand, and Min hand would overlap each other?
        View Answers (3)
    • This is from my friend who had a kernel development position interview. This is only phone interview.
      This is just from a phone interview:
      How did you port uCOSII to the product?

      How did you verify the worst case time delay?

      What are the key features that you are looking for the RTOS?
      (I mentioned the size, semaphore, event flags, and priority inheritance)

      What are cache write back and write through? give examples in what situation you use which?

      What are the major difference for the MCU and processors you are using?

      What are the top considerations you pick those processors or MCU?

      What are the programming model difference among those processors?

      What is volatile? examples of using it.

      A programming question:
      int32 multiplication( int16 a, int16 b)
      a "*" operator inside the func only takes 8 bit operands. what's the implementation?
      (I was a little bit stuck on the sign bit)

      What's the difference between DSP and MCU?
      (I guess he was looking for the Harvard architecture, I didn't get that until he mentioned that)

      What is the difference between desktop programming and embedded programming?
        Answer Question
    • This is for DSP Position phone interview
      Today I got phone interviewed for the DSP team. The scheduled time was 30 min, it went to about 50min, mostly because I talked too much, which is not very good thing.

      The first half an hour, he asked me a lot of questions on my resume

      1. How did you port rtos?
      2. what was the precise timing control?
      3. How did you improve FFT?
      ...

      In the second part he was focused on comm and dsp concepts,

      how to implement a FIR
      how to implement a filter with FFT?
      if PLL has statibily issue, where to look?
      Cell phone power control down to the radio power and already in the min power, how to reduce the interference to others?
      In signal space, the modulated signal got closer and closer, how to get better demodulation?
        Answer Question
    Negotiation Details
    I did not negotiate.
    Accepted Offer
    Positive Experience
    Difficult Interview
  9.  

    DSP Firmware Engineer Interview

    Anonymous Interview Candidate in San Diego, CA
    Anonymous Interview Candidate in San Diego, CA
    Application Details

    I applied through an employee referral. The process took a dayinterviewed at Qualcomm in April 2010.

    Interview Details

    I was referred by an employee and got email from the HR to set up the phone interview. After about 45 min I got the on site interview recommendation. During the phone interview I was asked a lot questions about what I was doing and and some theory algorithm associated with them. For example: How to do the channel estimation? How to implement the power control algorithm. all the technique related questions are based on the interviewer's working experience. I don't have on site interview scheduled yet. But my experience is you have to really know what your were doing and make the interviewer believes that you really did the work as you claimed.

    Interview Questions
    No Offer
    Positive Experience
    Average Interview
  10. 3 people found this helpful  

    DSP Firmware Engineer Interview

    Anonymous Interview Candidate in Santa Clara, CA
    Anonymous Interview Candidate in Santa Clara, CA
    Application Details

    The process took 4+ weeksinterviewed at Qualcomm in March 2010.

    Interview Details

    Passed Phone interview. Asked questions about DSP assembly. How do you perform a modulo without using the modulo operator? Asked about macm and how it handles 32bit multiplication.

    Next step was an onsite interview. About 6 hours. Asked questions about wireless theory, space-time block codes, OFDM, MIMO and fourier analysis. Had to write a C function that reversed bits given two indices in an int. More C questions about multi-threading, some questions about hardware and assembly languages.

    Interview Questions
    • Write a c functions that takes two bit indices and an int, and reverses the bits in the int between the two indices.   View Answers (4)
    • Describe why OFDM works as well as it does. Describe QAM modulation and the effects of channel offsets   Answer Question
    No Offer
    Positive Experience
    Difficult Interview
  11. 4 people found this helpful  

    DSP Firmware Engineer Wireless Modem Interview

    Anonymous Interview Candidate in Santa Clara, CA
    Anonymous Interview Candidate in Santa Clara, CA
    Application Details

    I applied online. The process took 6 weeksinterviewed at Qualcomm in January 2010.

    Interview Details

    The interview started by asking me about the graduate research that i was doing currently. Then it went on to my previous work experience. Then technical qtns for OFDM, Wideband channels etc. They asked me simple C qtns. One algorithm qtn & one puzzle type qtn. The interviewer was very professional & disciplined.
    It was very good experience. Have received a call for onsite interview.

    Interview Questions
    • Given 2 32 bit numbers, how do u multiply them using 8bit multipliers?   View Answer
    • Given 25 red balls & 25 blue balls. Arrange them in 2 bowls such that when a ball is picked randomly from one of bowls, the probability of picking red ball is maximum??   View Answer
    • qtns abt OFDM, qtns abt cyclic prefix, qtns abt wideband channel, qtns abt block convolution: overlap save   View Answer
    No Offer
    Positive Experience
    Average Interview

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