Telephone interview for 30 minutes, followed by an onsite interview of about 5 rounds.

Questions:

• SRNS relocation procedure

• What are the ranges of uplink and downlink frequencies in GSM? Which is higher and which is lower? Reasons why the higher frequency is used?

• Why is QPSK used in CDMA? Why is GMSK used in GSM?

• Waveform of GMSK? Properties of GMSK? How to generate GMSK?

• DPCM and delta modulation differences

• Authentication procedures between MS, SGSN, and HLR

• OFDM basics - Why OFDM? Interleaving? Disadvantages and advantages of OFDM. PAPR reduction techniques

• Sampling theorem related questions - Nyquist rate

• Result of the convolution of two sine waves of different frequencies

• Quantization related questions

• Rayleigh and Ricean fading differences

• Maximum number of PDP contexts per subscriber

• Integration and cyphering keys usage

• Explain paging of MS

• Functions of RNC

• Fields in MS network capability part in GMM attach message

• Messages involved in the basic attach procedure

• Reversing a singly linked list using one temporary variable without recursion

• Easy way to multiply a number by 7

• Given x, program to count the number of set bits in all numbers up to x

• Count the number of set bits in a number

• Write a program for a binary search tree

• Write a program to sort numbers using selection sort

• Questions related to malloc and calloc

• How to delete a particular node in a singly linked list if the address of the node to be deleted is the only information known

• What is a memory leak?

• What is a dangling pointer?

• Difference between enum and constant

• Data type of enum

• Static and global variables related questions

• Difference between local static and global static variables

• What is deadlock? Causes? Ways to avoid it?

• Page replacement in memory

• Mutex and semaphore concepts

• Process Control Block related questions

• Scheduling a process

• Scheduling algorithms

• What is message passing and how to synchronize concurrently running processes?

• Cache memory/virtual memory related questions

• How to cut a random piece of cake into two equal halves

• Building with n floors. Find the floor of least height where a pane of glass breaks when dropped, in a minimum number of attempts

• Derive the formula to find the volume of a pyramid and cylinder

• What is probability? Sample size? Probability related mathematical questions

• Circuits related - Draw AND gate, OR gate, XOR gate

• 2's complement of a number

• BCD addition related

Authentication procedures between Ms sgsn and HLR.