3G/UMTS Complete Mobile Originated Circuit Switched Call Setup

1. System Information (BCCH) The UE reads the System Information that is broadcast on BCCH. The information is not read continuously. It is only read if the information changes 2. RRC: RRC Connection Request (CCCH) The Mobile user decides to initiate a voice call. The first message the UE will send on CCCH is RRC Connection Request. This will contain among other things, Initial UE Identity and Establishment Cause 3. NBAP: Radio Link Setup Request The SRNC sends this message to Node B. It will pass the Cell Id, TFS, TFCS, frequency, UL Scrambling code, etc to Node B. 4. NBAP: Radio Link Setup Response Node B allocates the resources and starts PHY Reception. While transmitting the response it includes the Transport layer addressing information that includes the Binding Identity of the AAL2 for Iub data transport bearer 5. ALCAP: Establish REQ The AAL2 binding identity (Iub Data Transport Bearer Id) is passed to ALCAP protocol in Node B. The Iub Data Transport bearer is now bounf to DCH. 6. ALCAP: Establish CNF Establish confirm from ALCAP in Node B 7: DCH-FP: Downlink Synchronisation The Node B and SRNC establishes synchronisation for the Iub Data Transport bearer by means of exchange of the appropriate DCH Frame Protocol frames. 8: DCH-FP: Uplink Synchronisation Once the UL synchronisation is acheived, Node B starts DL transmission. 9: RRC: RRC Connection Setup (CCCH) RRC Connection Setup message is sent on CCCH with the parameters required to establish DCH. Also the state indicator will be set to DCH for the voice (or CS) call. 10: NBAP: Radio Link Restore Indication Once the UE establishes Radio Link, Node B will send RL Restore indication to the SRNC. 11: RRC: RRC Connection Setup Complete (DCCH) RRC Connection Setup complete will be sent on DCCH. Integrity and Ciphering related paarmeters and UE capability information will be sent back to SRNC 12: RRC: Initial Direct Transfer [CM Service Request] First NAS message is now sent by the UE. It indicates that a UE orginated Voice call is required. The UE identity (TMSI) will also be passed in this message 13: RANAP: Initial UE Message [CM Service Request] The NAS message will be forwarded to appropriate CN Domain (CS Domain in this case). Along with the CM service request, it will also include LAI and SAI. 14: RANAP: Direct Transfer [Authentication Request] MSC/VLR needs to perform authentication to make sure that the UE is genuine. For this reason it will challenge the UE with a Authentication token and RAND (random number) 15: RRC: Downlink Direct Transfer [Authentication Request] SRNC transfers the NAS message to the UE 16: RRC: Uplink Direct Transfer [Authentication Response] UE computes the response (RES) and sends it back in the NAS message 17: RANAP: Direct Transfer [Authentication Response] SRNC relays the response to the MSC/VLR. The MSC/VLR will compare the response RES with the expected response XRES. If they are the same then the procedure will continue. 18: RANAP: Security Mode Command MSC/VLR sends the Security Mode Command to start Ciphering and Integrity Protection. Ciphering is optional while Integrity Protection is mandatory. The Algorithms, etc are known to the MSC/VLR and the UE and only the ones that are common between them are used. 19: RRC: Security Mode Command RRC Forwards the Security Mode command received from MSC/VLR to the UE. 20: RRC: Security Mode Complete The UE configures the Ciphering and Integity Protection and responds back to the network. The response message is Integrity Protected for further safety. Ciphering is started at Ciphering activation time. Since this is a Circuit switched call, the Ciphering will be started in MAC. In case of AM and UM bearers it is started in RLC. 21: RANAP: Security Mode COmplete The network forwards the Security Mode Complete message to MSC/VLR. 22: RANAP: Direct Transfer [TMSI Reallocation Command] The network may decide to re-allocate the TMSI to the UE. It sends a DT message which includes the NAS TMSI Reallocation Command. 23: RRC: DL Direct Transfer [TMSI Reallocation Command] The RNC relays the DT message to the UE. 24: RRC: UL Direct TRansfer [TMSI Reallocation Complete] The UE takes the new TMSI and responds with the Complete message 25: RANAP: Direct Transfer [TMSI Reallocation Complete] The RNC relays the message to the CN domain 26: RRC: UL Direct TRansfer [Setup] The UE now sends the 'Setup' message in UL Direct Transfer message. This will include all the required parameters for setting up the voice call. It will include the number that UE wishes to be contacted and the bearer capability 27: RANAP: Direct TRansfer [Setup] The network relays the message to the MSC/VLR 28: RANAP: Direct TRansfer [Call Proceeding] The MSC/VLR sends Call Proceeding to the UE indicating that it is now starting with the RAB establishment procedure. 29: RRC: DL Direct TRansfer [Call Proceeding] The network relays it to the UE. 30: RANAP: RAB Assignment Request The CN initiates establishment of the Radio Access Bearer using the RAB Assignment Request message. This message includes the QoS of the call being established, the Transport Address, Iu Transport association, etc. 31: ALCAP: Establish REQ SRNC initiates the set-up of Iu Data Transport bearer using ALCAP protocol. The request contains the AAL2 Binding Identity to Bind the Iu Data Transport Bearer to the RAB. (Note that this is not done in case of PS RAB) 32: ALCAP: Establish CNF The CN responds with the ALCAP Establish CNF 33: NBAP: Radio Link Reconfiguration Prepare SRNC requests Node B to prepare establishment of DCH to carry the RAB. It passes the TFS, TFCS and Power Control Informnation in the message. 34: NBAP: Radio Link Reconfiguration Ready Node B allocates the resources and responds with the Ready message. It sends back the AAL2 address and the AAL2 binding Id for the Iub data transport bearer. 35: ALCAP: Establish REQ SRNC initiates setup of Iub Data Transport Bearer using ALCAP protocol. The request contains the AAL2 Binding Identity to bind the Iub Data Transport Bearer to DCH. 36: ALCAP: Establish CNF The Node B responds with the Establish Confirm. 37: DCH-FP: Downlink Synchronisation The Node B and SRNC establish synchronism for the Iub Data Transport Bearer by means of exchange of the appropriate DCH frame protocol frames. SRNC sends the DL Synchronisation frames. 38: DCH-FP: Uplink Synchronisation The Node B responds with the UE Synchronisation frames. 39: NBAP: Radio Link Reconfiguration Complete Finally the SRNC instructs the Node B of the CFN at which the new configuration will come into effect. 40: RRC: Radio Bearer Setup SRNC sends the RB Setup message to add the new DCH's. The message will be received using the old configuration. 41: RRC: Radio Bearer Setup Reponse After the activation time the UE will respond with complete message using the new configuration. 42: RANAP: RAB Assignment Reponse The SRNC responds with the response to the MSC/VLR. 43: ISUP: Initial Address Message MSC/VLR sends the Initial Address Message to the PSTN. The message tells the PSTN to reserve an idle trunk circuit from originating switch to the destination switch. 44: ISUP: Address Complete Message The ACM message is sent to indicate that the remote end of the trunk circuit has been reserved. 45: RANAP: Direct Transfer [Alert] The Alert message is sent to the SRNC. This message contains the ACM received from the PSTN. 46: RRC: Direct Transfer [Alert] The Alert message is forwarded to the UE. The Alert message will inditiate the ringing tone on the handset. 47: ISUP: Answer Message When the person that is being called picks up his phone, an Answer message is sent to the MSC/VLR. 48: RANAP: Direct Transfer [Connect] The MSC/VLR sends the Connect message to the SRNC via Direct Transfer message. The Connect message indictaes that the End User has answered the call. 49: RRC: DL Direct Transfer [Connect] The SRNC forwards the Connect message to the UE. 50: RRC: UL Direct Transfer [Connect Acknowledge] The UE confirms the reception of the Connect message using the Connect Acknowledge and sending it via Direct Transfer 51: RANAP: Direct Transfer [Connect Acknowledge] The Network forwards the Connect Acknowledge to the MSC/VLR. The call has now been successfully established.

Introduction to UMTS...layman called 3G....

Standing for "Universal Mobile Telecommunications System", UMTS represents an evolution in terms of capacity, data speeds and new service capabilities from second generation mobile networks.

Today, more than 60 3G/UMTS networks using WCDMA technology are operating commercially in 25 countries, supported by a choice of over 100 terminal designs from Asian, European and US manufacturers. Japanese operator NTT DoCoMo launched the world's first commercial WCDMA network in 2001.

A key member of the global family of third generation (3G) mobile technologies identified by the ITU, 3G/UMTS offers mobile operators significant capacity and broadband capabilities to support greater numbers of voice and data customers - especially in urban centres - plus higher data rates at lower incremental cost than 2G. Making use of radio spectrum in bands identified by the ITU for Third Generation IMT-2000 mobile services and subsequently licensed to operators, 3G/UMTS employs a 5 MHz channel carrier width to deliver significantly higher data rates and increased capacity compared with second generation networks. This 5 MHz channel carrier provides optimum use of radio resources, especially for operators who have been granted large, contiguous blocks of spectrum - typically ranging from 2x10 MHz up to 2x20 MHz - to reduce the cost of deploying 3G networks.

Crucially, 3G/UMTS has been specified as an integrated solution for mobile voice and data with wide area coverage. Universally standardised via the Third Generation Partnership Project (www.3gpp.org) and using globally harmonised spectrum in paired and unpaired bands, 3G/UMTS in its initial phase offers theoretical bit rates of up to 384 kbps in high mobility situations, rising as high as 2 Mbps in stationary/nomadic user environments. Symmetry between uplink and downlink data rates when using paired (FDD) spectrum also means that 3G/UMTS is ideally suited for applications such as real-time video telephony - in contrast with other technologies such as ADSL where there is a pronounced asymmetry between uplink and downlink throughput rates.

Specified and implemented as an end-to-end mobile system, 3G/UMTS also features the additional benefits of automatic international roaming plus integral security and billing functions, allowing operators to migrate from 2G to 3G while retaining many of their existing back-office systems. Offering increased capacity and speed at lower incremental cost compared with second generation mobile systems, 3G/UMTS gives operators the flexibility to introduce new multimedia services to business users and consumers while providing an enhanced user experience. This in turn provides the opportunity for operators to build on the brand-based relationships they already enjoy with their customers - and drive new revenue opportunities by encouraging additional traffic, stimulating new usage patterns and strengthening customer loyalty.

Ongoing technical work within 3GPP will see further increases in throughput speeds of the WCDMA Radio Access Network (RAN). High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA) technologies are already standardised and are undergoing network trials with operators in the Far East and North America. Promising theoretical downlink speeds as high as 14.4 Mbps (and respectively 5.8 Mbps uplink), these technologies will play an instrumental role in positioning 3G/UMTS as a key enabler for true 'mobile broadband'. Offering data transmission speeds of the same order of magnitude as today's Ethernet-based networks that are a ubiquitous feature of the fixed-line environment, 3G/UMTS will offer enterprise customers and consumers all the benefits of broadband connectivity whilst on the move.

3G - Mobile Evolution

Third Generation mobile in the shape of UMTS (Universal Mobile Telecommunications System) with WCDMA (Wideband Code Division Multiple Access) as radio access technology is already a reality.

With the first European networks already live and an increasing number of commercial launches anticipated during 2003, UMTS/WCDMA offers business users and consumers an evolution of their current mobile experience to add video and other exciting new services.

Approaching 120 licenses have already been awarded to operators worldwide, specifying WCDMA radio access technology that builds on GSM to provide a clear evolutionary path for more than 80% of the world's wireless market.

In terms of initial capital expenditure as well as ongoing operational costs, WCDMA technology offers new and existing operators alike a more economical platform to cope with projected growth in demand for voice and data services.

For customers already enjoying voice and data services via 2G and 2.5G, UMTS/WCDMA delivers even more of what they like doing already... faster, more efficiently and with new possibilities. For many of the 1.2 billion customers of second generation networks, UMTS is Third Generation mobile.

What are the implications of this continued growth in mobile subscriptions, the changing mix of voice and data revenues and the proliferation of new mobile terminal devices?

To address some of these questions, this section provides an overview of the market, technology, regulatory and service issues faced by network operators and manufacturers as well as the developers of mobile applications as they prepare their own 3G customer offerings.

In particular, it considers the benefits to industry and end users of a roadmap to and evolution of UMTS/WCDMA as part of the ITU/IMT-2000 standard.

What is femtocell ? is this Beneficial for us ?

In telecommunications, a femtocell is a small cellular base station, typically designed for use in a home or small business. It connects to the service provider’s network via broadband (such as DSL or cable); current designs typically support 2 to 4 active mobile phones in a residential setting, and 8 to 16 active mobile phones in enterprise settings. A femtocell allows service providers to extend service coverage indoors, especially where access would otherwise be limited or unavailable. Although much attention is focused on WCDMA, the concept is applicable to all standards, including GSM, CDMA2000, TD-SCDMA, WiMAX and LTE solutions.

For a mobile operator, the attractions of a femtocell are improvements to both coverage and capacity, especially indoors. Consumers benefit from improved coverage and potentially better voice quality and battery life. Depending on the carrier they may also be offered more attractive tariffs e.g. discounted calls from home.

Femtocells are an alternative way to deliver the benefits of fixed-mobile convergence (FMC). The distinction is that most FMC architectures require a new (dual-mode) handset which works with existing unlicensed spectrum home/enterprise wireless access points, while a femtocell-based deployment will work with existing handsets but requires installation of a new access point that uses licensed spectrum.

Many operators have launched femtocell service including Vodafone, AT&T, Sprint Nextel, Verizon and Mobile TeleSystems.

In 3GPP terminology, a Home NodeB (HNB) is a 3G femtocell. A Home eNodeB (HeNB) is an LTE femtocell.

Benefits for users /Usecase

The main benefits for an end-user are the following:

• "5 bar" coverage when there is no existing signal or poor coverage
• Higher mobile data capacity, which is important if the end-user makes use of mobile data on their mobile phone (may not be relevant to a large number of subscribers who instead use WiFi where femtocell is located)
• Depending on the pricing policy of the MNO, special tariffs at home can be applied for calls placed under femtocell coverage
• For enterprise users, having femtos instead of DECT phones enables them to have a single phone, so a single contact list etc