01 Huawei WCDMA Radio Interface Physical Layer

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0HUAWEI TECHNOLOGIES CO., LTD. All rights reservedwww.huawei.comInternaI WCDMA Radio nterface Physical LayerSSUE 1.01HUAWEI TECHNOLOGIES CO., LTD. Page 1 All rights reservedThe physical layer offers data transport services to higher layers. The access to these services is through the use of transport channels via the MAC sub-layer. The physical layer is expected to perform the following functions in order to provide the data transport service, for example Modulation and spreading/demodulation and despreading, nner -loop power control etc.2HUAWEI TECHNOLOGIES CO., LTD. Page 2 All rights reservedReferences TS 25.104 UTRA (BS) FDD Radio Transmission and Reception TS 25.201 Physical layer-general description TS 25.211 Physical channels and mapping of transport channels onto physical channels (FDD) TS 25.212 Multiplexing and channel coding (FDD) TS 25.213 Spreading and modulation (FDD) TS 25.214 Physical layer procedures (FDD) TS 25.308 UTRA High Speed Downlink Packet Access(HSDPA); Overall description; Stage 2 TR 25.877 High Speed Downlink Packet Acces (HSDPA) -ub/ur Protocol Aspects TR 25.858 Physical layer aspects of UTRA High Speed Downlink Packet Access3HUAWEI TECHNOLOGIES CO., LTD. Page 3 All rights reserved Upon completion of this course, you will be able to:Outline radio interface protocol ArchitectureDescribe key technology of UMTS physical layer Describe UMTS physical layer procedures4HUAWEI TECHNOLOGIES CO., LTD. Page 4 All rights reservedChapter 1 PhysicaI Layer Overview Chapter 1 PhysicaI Layer OverviewChapter 2 PhysicaI Layer Key TechnoIogy Chapter 2 PhysicaI Layer Key TechnoIogy Chapter 3 PhysicaI Layer Processing Procedure Chapter 3 PhysicaI Layer Processing ProcedureChapter 4 PhysicaI Layer Procedures Chapter 4 PhysicaI Layer Procedures5HUAWEI TECHNOLOGIES CO., LTD. Page 5 All rights reservedUTRAN Protocol StructureRNSRNCRNSRNCCore NetworkNodeB NodeB NodeB NodeBu uurub ubub ubUTRAN:UMTS Terrestrial Radio Access Network.The UTRAN consists oI a set oI Radio Network Subsystems connected to the Core Network through the Iu interIace.A RNS consists oI a Radio Network Controller and one or more NodeBs. A NodeB is connected to the RNC through the Iub interIace.Inside the UTRAN, the RNCs oI the RNS can be interconnected together through the Iur. Iu(s) and Iur are logical interIaces. Iur can be conveyed over direct physical connection between RNCs or virtual networks using any suitable transport network.6HUAWEI TECHNOLOGIES CO., LTD. Page 6 All rights reservedRadio nterface Protocol StructureL3controlcontrolcontrolcontrolLogical ChannelsTransport ChannelsC-plane signaling U-plane informationPHYL2/MACL1RLCDC Nt GCL2/RLCMACRLCRLCRLCRLC RLCRLCRLCDupIication avoidanceUuS boundaryBMC L2/BMCcontrolPDCPPDCP L2/PDCPDC Nt GCRadio BearersRRCThe radio interIace (Uu) is layered into three protocol layers:the physical layer (L1)the data link layer (L2)the network layer (L3).The layer 1 supports all Iunctions required Ior the transmission oI bit streams on the physical medium. It is also in charge oI measurements Iunction consisting in indicating to higher layers, Ior example, Frame Error Rate (FER), Signal to Interference Ratio (SIR), interIerence power, transmit power, . It is basically composed oI a 'layer 1 management entity, a 'transport channel entity, and a 'physical channel entity.The layer 2 protocol is responsible Ior providing Iunctions such as mapping, ciphering, retransmission and segmentation. It is made oI Iour sublayers: MAC(Medium Access Control), RLC (Radio Link Control), PDCP (Packet Data Convergence Protocol) and BMC (Broadcast/Multicast Control). The layer 3 is split into 2 parts: the access stratum and the non access stratum. The access stratum part is made oI 'RRC (Radio Resource Control) entity and 'duplication avoidance entity. The non access stratum part is made oI CC, MMparts.Not shown on the Iigure are connections between RRC and all the other protocol layers (RLC, MAC, PDCP, BMC and L1), which provide local inter-layer control services.The protocol layers are located in the UE and the peer entities are in the node B or the RNC.7Many Iunctions are managed by the RRC layer. Here is the list oI the most important:Establishment, re-establishment, maintenance and release of an RRC connection between the UE and UTRAN: it includes an optional cell re-selection, an admission control, and a layer 2 signaling link establishment. When a RNC is in charge oI a speciIic connection towards a UE, it acts as the Serving RNC.Establishment, reconfiguration and release of Radio Bearers: a number oI Radio Bearers can be established Ior a UE at the same time. These bearers are conIigured depending on the requested QoS. The RNC is also in charge oI ensuring that the requested QoS can be met.Assignment, reconfiguration and release of radio resources for the RRC connection: it handles the assignment oI radio resources (e.g. codes, shared channels). RRC communicates with the UE to indicate new resources allocation when handovers are managed.Paging/Notification: it broadcasts paging inIormation Irom network to UEs.Broadcasting of information provided by the non-access stratum (Core Network) or access Stratum. This corresponds to 'system inIormation regularly repeated.UE measurement reporting and control of the reporting: RRC indicates what to measure, when and how to report.Outer loop power control: controls setting oI the target values.Control of ciphering: provides procedures Ior setting oI ciphering.The RRC layer is deIined in the 25.331 speciIication Irom 3GPP.The RLC`s main Iunction is the transIer oI data Irom either the user or the control plane over the Radio interIace. Two diIIerent transIer modes are used: transparent and non-transparent. In non-transparent mode, 2 sub-modes are used: acknowledged or unacknowledged.RLC provides services to upper layers: data transfer (transparent, acknowledged and unacknowledged modes),QoS setting: the retransmission protocol (Ior AM only) shall be conIigurable by layer 3 to provide diIIerent QoS,notification of unrecoverable errors: RLC notiIies the upper layers oI errors that cannot be resolved by RLC.The RLC Iunctions are:mapping between higher layer PDUs and logical channels,ciphering: prevents unauthorized acquisition oI data; perIormed in RLC layer Ior non-transparent RLC mode,segmentation/reassembly: this Iunction perIorms segmentation/reassembly oI variable-length higher layer PDUs into/Irom smaller RLC Payload Units. The RLC size is adjustable to the actual set oI transport Iormats (decided when service is established). Concatenation and padding may also be used,error correction: done by retransmission (acknowledged data transIer mode only),flow control: allows the RLC receiver to control the rate at which the peer RLC transmitting entity may send inIormation.8MAC services include: Data transfer: service providing unacknowledged transIer oI MAC SDUs between peer MAC entities.Reallocation of radio resources and MAC parameters: reconIiguration oI MAC Iunctions such as change oI identity oI UE. Requested by the RRC layer.Reporting of measurements: local measurements such as traIIic volume and quality indication are reported to the RRC layer.The Iunctions accomplished by the MAC sublayer are listed above. Here`s a quick explanation Ior some oI them:Priority handling between the data flows of one UE: since UMTS is multimedia, a user may activate several services at the same time, having possibly diIIerent proIiles (priority, QoS parameters...). Priority handling consists in setting the right transport Iormat Ior a high bit rate service and Ior a low bit rate service.Priority handling between UEs: use Ior eIIicient spectrum resources utilization Ior bursty transIers on common and shared channels.Ciphering: to prevent unauthorized acquisition oI data. PerIormed in the MAC layer Ior transparent RLC mode.Access Service Class (ACS) selection for RACH transmission: the RACH resources are divided between diIIerent ACSs in order to provide diIIerent priorities on a random access procedure.PDCPUMTS supports several network layer protocols providing protocol transparency Ior the users oI the service.Using these protocols (and new ones) shall be possible without any changes to UTRAN protocols. In order to perIorm this requirement, the PDCP layer has been introduced. Then, Iunctions related to transIer oI packets Irom higher layers shall be carried out in a transparent way by the UTRAN network entities.PDCP shall also be responsible Ior implementing diIIerent kinds oI optimization methods. The currently known methods are standardized IETF (Internet Engineering Task Force) header compression algorithms.Algorithm types and their parameters are negotiated by RRC and indicated to PDCP.Header compression and decompression are speciIic Ior each network layer protocol type.In order to know which compression method is used, an identiIier (PID: Packet IdentiIier) is inserted. Compression algorithms exist Ior TCP/IP, RTP/UDP/IP, .Another Iunction oI PDCP is to provide numbering oI PDUs. This is done iI lossless SRNS relocation is required.To accomplish this Iunction, each PDCP-SDUs (UL and DL) is buIIered and numbered. Numbering is done aIter header compression. SDUs are kept until inIormation oI successIul transmission oI PDCP-PDU has been received Irom RLC. PDCP sequence number ranges Irom 0 to 65,535. 9BMC (broadcast/multicast control protocol)The main Iunction oI BMC protocol are:Storage of cell broadcast message. the BMC in RNC stores the cell broadcast message received over the CBC-RNC interIace Ior scheduled transmission.Traffic volume monitoring and radio resource request for CBS. On the UTRAN side, the BMC calculates the required transmission rate Ior the cell broadcast service based on the messages received over the CBC-RNC interIace, and requests appropriate .CTCH/FACH resources Irom Irom RRCSchedu