what is the diffrence about RSRP-SINR-RSRQ-RSSI?

RSRP: - Reference signal receive power.RSRP (dBm) = RSSI (dBm) -10*log (12*N)

where RSSI = Received Signal Strength IndicatorN: number of RBs across the RSSI is measured and depends on the BW

Significance:RSRP is the most basic of the UE physical layer measurements and is the linear average power (in watts) of the downlink reference signals (RS) across the channel bandwidth for the Resource elements that carry cell specific Reference Signals.

Knowledge of absolute RSRP provides the UE with essential information about the strength of cells from which path loss can be calculated and used in the algorithms for determining the optimum power settings for operating the network. Reference signal receive power is used both in idle and connected statesRange: - -44 to -140 dBm

RSRP term is used for coverage same as RSCP in 3G

RSRQ: Reference signal receive quality

RSRQ = RSRP / (RSSI / N)

N is the number of resource blocks over which the RSSI is measured

RSSI is wide band power, including intra cell power, interference and noise.

Significance: -It provides the Indication of Signal Quality. Measuring RSRQ becomes particularly important near the cell edge when decisions need to be made, regardless of absolute RSRP, to perform a handover to the next cell. Reference signal receive quality is used only during connected states

Range: - -3 to -19.5 dB RSRQ term is used for Quality same as Ec/No in 3G. SINR: - Signal to Noise Ratio.SINR = S / I + N

S -- Average Received Signal PowerI -- Average Interference powerN -- Noise Power

Significance: Is a way to measure the Quality of LTE Wireless Connections. As the energy of signal fades with distance i.e. Path Loss due to environmental parameters (e.g. background noise, interfering strength of other simultaneous transmission)

what is the process when one UE power on and access to netwotk?

When a UE is powered on or recovers from lack ofCoverage, the UE first selects the last RPLMN and attempts to register on that PLMN. If the registrationOn the PLMN is successful, the UE shows the selected PLMN on the display, and now it can obtainService from an operator. If the last RPLMN is unavailable or the registration on the PLMN fails, anotherPLMN can be automatically or manually selected according to the priorities of PLMNs stored in theUSIM.

What is the difference about TCP and UDP?

TCP UDP

Acronym forTransmission Control ProtocolUser Datagram Protocol or Universal Datagram Protocol

ConnectionTCP is a connection-oriented protocol.UDP is a connectionless protocol.

FunctionAs a message makes its way across the internet from one computer to another. This is connection based.UDP is also a protocol used in message transport or transfer. This is not connection based which means that one program can send a load of packets to another and that would be the end of the relationship.

UsageTCP is suited for applications that require high reliability, and transmission time is relatively less critical.UDP is suitable for applications that need fast, efficient transmission, such as games. UDP's stateless nature is also useful for servers that answer small queries from huge numbers of clients.

Use by other protocolsHTTP, HTTPs, FTP, SMTP, TelnetDNS, DHCP, TFTP, SNMP, RIP, VOIP.

Ordering of data packetsTCP rearranges data packets in the order specified.UDP has no inherent order as all packets are independent of each other. If ordering is required, it has to be managed by the application layer.

Speed of transferThe speed for TCP is slower than UDP.UDP is faster because there is no error-checking for packets.

ReliabilityThere is absolute guarantee that the data transferred remains intact and arrives in the same order in which it was sent.There is no guarantee that the messages or packets sent would reach at all.

Header SizeTCP header size is 20 bytesUDP Header size is 8 bytes.

Common Header FieldsSource port, Destination port, Check SumSource port, Destination port, Check Sum

Streaming of dataData is read as a byte stream, no distinguishing indications are transmitted to signal message (segment) boundaries.Packets are sent individually and are checked for integrity only if they arrive. Packets have definite boundaries which are honored upon receipt, meaning a read operation at the receiver socket will yield an entire message as it was originally sent.

WeightTCP is heavy-weight. TCP requires three packets to set up a socket connection, before any user data can be sent. TCP handles reliability and congestion control.UDP is lightweight. There is no ordering of messages, any tracking connections, etc. It is a small transport layer designed on top of IP.

Data Flow ControlTCP does Flow Control. TCP requires three packets to set up a socket connection, before any user data can be sent. TCP handles reliability and congestion control.UDP does not have an option for flow control

Error CheckingTCP does error checkingUDP does error checking, but no recovery options.

Fields1. Sequence Number, 2. AcK number, 3. Data offset, 4. Reserved, 5. Control bit, 6. Window, 7. Urgent Pointer 8. Options, 9. Padding, 10. Check Sum, 11. Source port, 12. Destination port1. Length, 2. Source port, 3. Destination port, 4. Check Sum

AcknowledgementAcknowledgement segmentsNo Acknowledgment

HandshakeSYN, SYN-ACK, ACKNo handshake (connectionless protocol)

Checksumchecksumto detect errors

Do you know CSFB? The process of CSFB by L3 messages? What condition will make one ue redirection to 3G? What condition will make one ue reselection from 3G back to LTE?

What information included in Sib3-Sib6-Sib9 message? What is the use of this message?

SIB (System Information Block )System Information provides information to the UEs about various parameters of both the Access Stratum and Non Access Stratum. These are the parameters that are common for all the UEs in the same cell and are traditionally broadcasted in all the wireless technologies. UEs use this information for multiple purposes, mainly system access and other idle mode procedures like cell selection, reselection etc.

In LTE, main system information consists of the following:1.Master Information Block (MIB) : MIB gives information about the most important parameters like SFN, system bandwidth( In Terms of RBs) and HICH configuration. It is transmitted every 40 ms and the scheduling information is standardized.2. System Information Block1: SIB1 is scheduled every 80ms. SIB1 broadcasts cell access related parameters -cell identifier (plmn id, cell id), qrxlevmin, cell specific timers and the scheduling information for all other SIBs.3. System Information Block2: SIB2 provides information about common and shared channels-rach, prach, bcch, dlsch, ulsch etc. 4.System Information Block 3 to 8 provides information required for cell reselection.SI3 provides information on intra frequency cell reselection except neighbor cell information.SIB4 provides info on neighbor cell informations. SIB5 is for inter frequency cell reselection, SIB6 is for UTRAN, SIB7 for GERAN and SIB8 for CDMA related cell reselection.SIB9: Name of the home eNodeB

UE reads the system information during the initial attach process and whenever it is camped to a new cell, it reads the relevent sysinfos.If some System Information value is changed, the network pages the UE telling the UEs that system information is changed and UEs will read the system info during the next modification cycle. Modification cycle is a cell specific parameter that is signaled in the sib2.Whenever the UE receives a paging indicating sib modification, it will invalidate all the sysinfos and retrieve all the sysinfos again How to use FMA to analysis CHR logs?