TelecomStudy18

Mobility Management Entity (MME) – MME is a controller at each node on the LTE access network. At UE in idle state (idlemode), MME is responsible for tracking and paging procedure which includes retransmission therein. – MME is responsible for selecting SGW (Serving SAE Gateway) which will be used during initial attach EU and the EU time to do intra-LTE handover. – Used for bearer control, a different viewR99/4 whichis still controlled by the gateway Serving SAE Gateway (SGW) -Set the path and forwards the data in the form of packets of each user-As an anchor / liaison between the UE and the eNBat the time of the inter handover-As a liaison link between the 3GPP LTE technology with the technology (in this case the 2G and 3G) Gateway Packet Data Network (PDN GW) -Provides for the UE 's relationship to the network packet-Provide a link relationship between LTE technology with technology non 3GPP (WiMAX) and 3GPP2 (CDMA 20001X and EVDO)

NAS signalling; NAS signalling security; AS Security control; Inter CN node signalling for mobility between 3GPP access networks; Idle mode UE Reachability (including control and execution of paging retransmission); Tracking Area list management (for UE in idle and active mode); PDN GW and Serving GW selection; MME selection for handovers with MME change; SGSN selection for handovers to 2G or 3G 3GPP access networks; Roaming; Authentication; Bearer management functions including dedicated bearer establishment; Support for PWS (which includes ETWS and CMAS) message transmission.

In cellular networks, when a mobile moves from cell to cell and performs cell selection/reselection and handover, it has to measure the signal strength/quality of the neighbor cells. In LTE network, a UE measures two parameters on reference signal: RSRP (Reference Signal Received Power) and RSRQ (Reference Signal Received Quality). RSRP is a RSSI type of measurement. It measures the average received power over the resource elements that carry cell-specific reference signals within certain frequency bandwidth. RSRP is applicable in both RRC_idle and RRC_connected modes, while RSRQ is only applicable in RRC_connected mode. In the procedure of cell selection and cell reselection in idle mode, RSRP is used. RSRQ is a C/I type of measurement and it indicates the quality of the received reference signal. It is defined as (N*RSRP)/(E-UTRA Carrier RSSI), where N makes sure the nominator and denominator are measured over the same frequency bandwidth; The carrier RSSI (Rece

What are the possible causes for a Drop Call on a UMTS network?               Poor Coverage (DL / UL)  Pilot Pollution / Pilot Spillover  Missing Neighbor  SC Collisions  Delayed Handovers  No resource availability (Congestion) for Hand in  Loss of Synchronization  Fast Fading  Delayed IRAT Triggers  Hardware Issues  External Interference

What are the possible causes for an Access Failure in UMTS?       ·          Missing Neighbors ·          Poor Coverage ·          Pilot Pollution / Spillover ·          Poor Cell Reselection ·          Core Network Issues ·          Non – availability of resources. Admission Control denies ·          Hardware Issues Improper RACH Parameters External Interference

What are the processing gains for CS and PS services? CS12.2:     25dB PS-64:       18dB PS-128:     15dB PS-384:     10dB HSDPA:      2dB

Basic Parameters of WCDMA Frequency Band                                      :            2100 MHz 1920-1980MHz (UL) &2110-2170 MHz (DL) Duplex Space                                         :            190 MHz Channel bandwidth                                 :            5 MHz Coding Spacing                                       :            200 KHz (RASTER) UARFCN Range                                        :            10562-10838 (Total ARFCN – 276) Duplex mode                                          :            FDD and TDD Downlink RF channel structure                  :            Direct spread Chip rate& Chips                                     :            3.84 Mcps& It is pulse of spreading spectrum n                                                                           It’s in rectangular shape of +1 & -1 Frame length                                         :            10 ms (38400 chips) = 15Slots, & 1slot = 2650chips