What is Difference between MIB and SIB?

MIB and SIM are two types of System Information (SI) that is broadcasted in the serving are of particular cell. SI is carried by the logical channel BCCH, which in turn is carried by either of the transport channels BCH or DL-SCH.

Master information Block (MIB): is a static part of SI and contain information like number of antennas, system bandwidth,PHICH configuration, transmitted power and scheduling information on how the SIBs are scheduled together with other data on DL-SCH. MIB is transmitted on the BBCH–> PBCH with periodicity of every 40 ms.

System Information Block (SIB): is a dynamic part of SI. It carry relevant information for the UE, which helps UE to access a cell, perform cell re-selection, information related to INTRA-frequency, INTER-frequency and INTER-RAT cell selections. It is mapped on DL-SCH –>PDSCH with periodicity of every 80 ms, 160ms or 320ms for SIB1,SIB2 and SIB3 respectively.

How many types of SIBs are available in LTE?

There are 13 types of SIBs for LTE.

 What does SIB1/SIB2/ … /SIB13 do?

Each SIB carry information related to specific tasks.

SIB-1 Carries Cell access related parameters like cell ID, MCC, MNC, TAC, scheduling of other SIBs
SIB-2 Carries Common and shared channel configuration, RACH related configuration are present; RRC, uplink power control, preamble power ramping, uplink Cyclic Prefix Length, sub-frame hopping, uplink EARFCN
SIB-3 Parameters required for intra-frequency, inter-frequency and I-RAT cell re-selections
SIB-4 Information regarding INTRA-frequency neighboring cells (E-UTRA)  carries serving cell and neighbor cell frequencies required for cell reselection as well handover
SIB-5 Information regarding INTER-frequency neighboring cells (E-UTRA); carries E-UTRA LTE frequencies, other neighbor cell frequencies from other RATs.
SIB-6 Information for re-selection to INTER-RAT (UTRAN cells)
SIB-7 Information for re-selection to INTER-RAT (GERAN cells)
SIB-8 Information for re-selection to INTER-RAT (CDMA2000)
SIB-9 Information related to Home eNodeB  (FEMTOCELL)
SIB-10 ETWS (Earthquake and Tsunami Warning System) information (Primary notification)
SIB-11 ETWS (Earthquake and Tsunami Warning System) information (Secondary notification)
SIB-12 Commercial Mobile Alert Service (CMAS) information.
SIB-13 Contains the information required to acquire the MBMS control information associated with one or more MBSFN areas.

Explore below link to know more about earch and every SIB,

On which channels SIBs are transmitted?

Which SIBs are essential?

In LTE, for a UE to access the eNB, at the most minimum 2 SIBs are required (SIB1 and SIB2). Information regarding SIB2-SIB13 are carried in SI messages and are included in schedulingInfoList which is part of SIB1.

Why we need SIB19?
SIB 19 is needed when UE is coming back from 3G to 4G. LTE priority should be set high in 3G. SIB19 carries the absolute priority of the serving UMTS cell, the absolute priorities of the LTE frequencies, and the cell reselection thresholds.

HO , Redirection, Cell Selection and Re-Selection

What is difference between HO , Redirection, Cell Selection and Re-Selection?

Handover (HO): UE moves from one eNB to target eNB while keeping its connected state. LTE Services will be uninterrupted.

In handover procedure, target cell would be prepared and UE will latch on target cell based on the configuration sent by source enodeb to UE.

Redirection: UE changes its state from connected to Idle mode during Redirection. LTE Service will be interrupted. Meaning the Source ENB shall release the connection of the UE and will ask the UE to redirect itself onto the target ENB by indicating the carrier frequency or the cell id in the RRC connection release message. For example, During CS Fallback, the UE is redirected from LTE RRC_CONNECTED mode to (2G/3G) idle mode).

 Cell Selection: It allows a UE to search and camp on a suitable cell. Cell selection occurs during Initial cell selection (when UE switches ON),  Stored information cell selection (uses stored cell info to identify appropriate cell),  and Cell selection when leaving RRC connected mode (When UE move from RRC CONNECTED to RRC IDLE mode)

 Cell Reselection: Its Idle mode procedure and happens from idle mode to idle mode. Reselection can occue on cell within same RAT (Intra-RAT) or different RAT(Inter-RAT).

Is a NULL value same as zero or a blank space? If not then what is the difference?

  1. Null is an absence of a value. An empty string is a value, but is just empty. Null is special to a database.
  2. Null has no bounds, it can be used for string, integer, date, etc. fields in a database.
  3. NULL isn’t allocated any memory, the string with NUll value is just a pointer which is pointing to nowhere in memory. however, Empty IS allocated to a memory location, although the value stored in the memory is "".

What is data integrity in database

data integrity” refers to the accuracy and consistency of data stored in a database, data warehouse, data mart or other construct. The term –Data Integrity – can be used to describe a state, a process or a function – and is often used as a proxy for “data quality”.

What is a constraint?

SQL constraints are used to specify rules for the data in a table.

If there is any violation between the constraint and the data action, the action is aborted by the constraint.

Constraints can be specified when the table is created (inside the CREATE TABLE statement) or after the table is created (inside the ALTER TABLE statement).

What is sub query? And what are the types of sub query?

A subquery is a SELECT statement within another statement.

  • A subquery may occur in :
    • – A SELECT clause
    • – A FROM clause
    • – A WHERE clause
  • The subquery can be nested inside a SELECT, INSERT, UPDATE, or DELETE statement or inside another subquery.
  • A subquery is usually added within the WHERE Clause of another SQL SELECT statement.
  • You can use the comparison operators, such as >, <, or =. The comparison operator can also be a multiple-row operator, such as IN, ANY, or ALL.
  • A subquery is also called an inner query or inner select, while the statement containing a subquery is also called an outer query or outer select.
  • The inner query executes first before its parent query so that the results of an inner query can be passed to the outer query.

Types of Subquery

  • Single row subquery : Returns zero or one row.
  • Multiple row subquery : Returns one or more rows.
  • Multiple column subqueries : Returns one or more columns.
  • Correlated subqueries : Reference one or more columns in the outer SQL statement. The subquery is known as a correlated subquery because the subquery is related to the outer SQL statement.
  • Nested subqueries : Subqueries are placed within another subquery.

What is a query?

A query is an inquiry into the database using the SELECT statement. A query is used to extract data from the database in a readable format according to the user’s request.

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