1 Comment

1. 

   AYESHA MUMTAZ on February 8, 2019 at 5:13 pm

   Q 1: Briefly note on BCH code and its working.  BCH … Discoverer: Bose, Chaudhuri and Hocquenghem.  Multiple error correcting codes  Generalization of Hamming Code.  Flexibility in choice of parameters: Block length, code rate
    For positive pair of integers m and t, a (n, k) BCH code has parameters:
   Block length: n = 2m – 1
   Number of check bits: n – k = 2t + 1
    Correct combinations of t or fewer errors  The generator polynomial can be constructed from the factors of (X
   2m-1 +1)
   Q 2: Write down the classes of A/Gb mode of GPRS.  Class A: MS can operate simultaneous packet switched and circuit switched services.  Class B: MS can operate either one at one time – Most common for handsets today.  Class C: MS can operate only packet switched services – e.g. Expansion cards for laptops. Q 3: How MULTIMEDIA further divides in UMATS types?
   Service classes in UMTS
    In 3G network, ME will be able to establish multiple connections simultaneously.  Network allows efficient cooperation between application with diverse quality of service
   requirements.  The quality can be defined by two main parameters
   Guaranteed and max bit rate possible (kbps)
   Permissible delay (ms)
   Based on the QoS criteria, multimedia services has been further classified
    Conversational: The most delay sensitive, e.g. applications video telephony, VoIP
    Streaming: Flow which is steady and continuous, it is server to user  Interactive: Web browsing is an example. A user may request timetables of buses, trains or
   flight schedule
    Background: Short messages, file transfer, ema
   http://www.vuassassins.com
    Works in circuit switch mode.  Speed increased by allowing single user to use consecutive time slots in GSM standard
    Relaxes error control coding algorithms specified in GSM increasing data rate from 9.600 to
   14.400 Kbps  By using 4 slots, raw data rate of up to 57.6 kbps to individual user.  Ideal for dedicated streaming or real-time interactive web sessions
   Q 5: Write brief note on EDGE.  EDGE2.75G More advanced upgrade to 2G that requires addition of new hardware and
   software
    Developed as a path to become eventual 3G high speed data access  New modulation 8-PSK in addition to GSM standard GMSK.  Allows nine different formats known as Multiple modulation and Coding Scheme (MCS)  Each MCS state may either use GMSK (low rate) or 8-PSK (high rate).  A family of MCS for each GSM slot and users can adaptively determine best MCS setting
    User start first with max error protection and max data rate until the link has unacceptable
   outage or delay
    By combining different channels (multi-carrier trans), EDGE provides upto several megabits
   per second data throughput. Q 6: Issues regarding handoff in interSystem.
   If a mobile moves from one cellular system to a different system controlled by a different MSC
   Issues to be addressed
   1. A local call becomes a long-distance call (roaming)
   2. Compatibility between two MSC must be determined
   3. Different systems have different policies and methods for managing handoff requests
   Q 7: Write about QoS profile in GPRS bearer
   QoS Profile for GPRS Bearers
   4 parameters:
   1. Service precedence: 3 classes
   http://www.vuassassins.com
   2. Reliability parameter: 3 classes
   3. Delay parameters: 4 classes
   4. Throughput parameter: Maximum and mean bit rates
   QoS profile is included in Packet Data Protocol (PDP) context
   Negotiation managed through PDP procedures (activation, modification and deactivation)
   Q 8: Describe about Call routing in GSM network with Detailed diagram
   Frequent path breaks due to mobility
   High cost and time of deployment Quick and cost-effective deployment
   http://www.vuassassins.com