NQ&O Report

UMTS

UMTS1

UMTS1What is UMTS ?Universal Mobile Telecommunications System (UMTS)

UMTS is an upgrade from GSM

The standardization work for UMTS is carried out by Third Generation Partnership Project (3GPP)

UMTS22 Evolution of UMTSUMTS3

3 UMTS Architecture High LevelUMTS4Functional network elementsUser Equipment (UE)interfaces with user and radio interfaceRadio Access Network (RAN, UMTS Terrestrial RAN = UTRAN)handles all radio-related functionalityCore Networkswitches and routes calls and data connections to external networks

4 UMTS ArchitectureUMTS5USIMMENode BNode BRNCNode BNode BRNCMSC/VLRGMSCSGSNGGSNHLRUTRANCNUEExternal NetworksCuUuIuIubIur5 UMTS Architecture - DetailedUMTS6

6 UMTS Architecture - DetailedUMTS7

7 UMTS Architecture - DetailedUMTS8

8 UMTS Terrestrial Radio Access Network - UTRANUMTS9Two Distinct Elements :Base Stations (Node B)Radio Network Controllers (RNC)

Handles all Radio-Related Functionality

Soft HandoverRadio Resources Management Algorithms

Maximization of the commonalities of the PS and CS data handlingNode BNode BRNCNode BNode BRNCIubIurRNSRNS9 UMTS Core NetworkUMTS10CS Domain :Mobile Switching Centre (MSC) Switching CS transactions

Visitor Location Register (VLR)Holds a copy of the visiting users service profile, and the precise info of the UEs location

Gateway MSC (GMSC)The switch that connects to external networks

PS Domain :Serving GPRS Support Node (SGSN)Similar function as MSC/VLR

Gateway GPRS Support Node (GGSN)Similar function as GMSC

Home Location Register (HLR)Stores master copies of users service profilesStores UE location on the level of MSC/VLR/SGSN

MSC/VLRGMSCSGSNGGSNHLRExternal NetworksIu-csIu-ps10 UMTS - CS DomainUMTS11CS domain has the following elements:Mobile Switching Centre (MSC), including Visitor Location Register (VLR)Gateway MSC (GMSC)

11 UMTS - PS DomainUMTS12PS domain has the following elementsServing GPRS Support Node (SGSN)covers similar functions as MSC for packet data, including VLR type functionalityGateway GPRS Support Node (GGSN) connects PS core network to other networks, e.g. to the Internet

12 Common Databases - RegistersUMTS13In addition to the two domains, the network needs various registers for proper operationHome Location Register (HLR)Equipment Identity Register (EIR)contains the information related to the terminal equipment can be used to, e.g., prevent a specific terminal from accessing the network

13 Power ControlUMTS14Prevent Excessive Interference and Near-far Effect

Open-Loop Power ControlRough estimation of path loss from receiving signalInitial power setting, or when no feedback channel is exist

Fast Close-Loop Power ControlFeedback loop with 1.5kHz cycle to adjust uplink / downlink power to its minimumEven faster than the speed of Rayleigh fading for moderate mobile speeds

Outer Loop Power ControlAdjust the target SIR set point in base station according to the target BERCommanded by RNC

Fast Power ControlIf SIR < SIRTARGET, send power up command to MSOuter Loop Power ControlIf quality < target, increases SIRTARGET14 HandoversUMTS15Softer HandoverA MS is in the overlapping coverage of 2 sectors of a base stationConcurrent communication via 2 air interface channels2 channels are maximally combined with rake receiver

Soft HandoverA MS is in the overlapping coverage of 2 different base stationsConcurrent communication via 2 air interface channelsDownlink: Maximal combining with rake receiverUplink: Routed to RNC for selection combining, according to a frame reliability indicator by the base station

These handovers provides a Kind of Macro-diversity

NodeB1NodeB - XNodeB - YUEUERNC 1RNC 215 HSDPA Vs HSUPAUMTS16HSPA (High Speed Packet Access), commonly referred to as 3.5G, is an upgrade to WCDMA networks that allows for much higher data speeds for internet connectivity. HSDPA (High Speed Downlink Packet Access) is the one that improves the downlink of the data transmission while HSUPA (High Speed Uplink Packet Access) is the one that improves the uplink or transmission from the mobile device to the network.

16 HSDPAUMTS17High Speed Downlink Packet Access

Standardized in 3GPP Release 5

Improves System Capacity and User Data Rates in the Downlink Direction to 42Mbps in a 5MHz Channel

Adaptive Modulation and Coding (AMC)Replaces Fast Power Control :User farer from Base Station utilizes a coding and modulation that requires lower Bit Energy to Interference Ratio, leading to a lower throughputReplaces Variable Spreading Factor :Use of more robust coding and fast Hybrid Automatic Repeat Request (HARQ, retransmit occurs only between MS and BS)

HARQ provides Fast Retransmission with Soft Combining and Incremental Redundancy

Soft Combining : Identical RetransmissionsIncremental Redundancy : Retransmits Parity Bits only

Fast Scheduling Functionwhich is Controlled in the Base Station rather than by the RNC

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