Research And Implementation Of CRBTS Based On CPH In CAMEL Phase 4 Of Mobile Intelligent Network

Current mobile communication system uses the CAMEL (CustomizedApplications for Mobile network Enhanced Logic) technology to implementall kinds of wireless intelligent services for the users. But with thedevelopment of 3rd Generation Mobile Communication Technology, thecurrent CAMEL system couldn't suffice the development. So the 3GPP (3rdGeneration Partnership Project) Organization designed the CAMEL4(CAMEL Phase4), the new generation of CAMEL technology. The maincharacteristic of CAMEL4 is Call Party Handling (CPH).Based on CPH, a series of User Interaction Service can be made, such asColor Ring-Back Tone (CBRT) service, Intelligent Network TelephoneConference and Booking & Playing Service. User Interaction Service is theservice that can provide choices of users referring to the requirement of themarketing on the basis of the mobile basic service. User Interaction Service isproduced quickly, conveniently, economically, flexibly and efficiently by theIntelligent Network. And the CRBT is the most popular services among theUser Interaction Service. What is CRBT? The answer is that Voice and Music Ring Back Tone,also known as "Color Ring Back Tone" allows a user to select a personal tune,song or clip. This is used to overwrite the traditional "boring" ring back tone,which is played when a caller tries to reach the mobile handset user. Users canselect their tone/clip from a large pool supplied by a content provider througha Web or IVR server. (Users pay approximately one dollar per month for thisservice). Some operators enable the users to add their announcement on top ofthe clip for an extra charge, but one that is still relatively inexpensive. The CRBT is an attractive incentive for mobile phone service providersnot only to seek a quick return on their capital expenditure, but also to attractnew customers, minimize churn, increase ARPU and increase market share.There are several wireless providers that are already supplying this service,like in Korea, Japan, Malaysia, China, Hong Kong and Israel. In many othercountries in Europe and in the US the CRBT service is going to be launchedby early 2004. In the Asia-Pacific region, CRBT technology is fast gainingground, especially in mature wireless markets such as South Korea, where theservice attracted over 6 million subscribers nine months since its launch inApril 2002. Mobile operators grappling for ways to generate new revenuesmay consider pioneering a CRBT service in their respective countries. With anattractive pricing model, users are likely to take on this service which could, inturn, enhance usage of WAP, Mobile Internet, SMS and even voice services.Currently, the solutions of CRBT are divided into two parts. One is basedon MSC, and the other one is based on intelligent network. The supportedtriggering modes of CRBT service include NPI of calling MSC, SS_CODE ofcalled MSC, and WIN ALERTING PATTERN.Calling MSC connects the tone server to which the caller is homedaccording to the caller's subscription information in the called HLR. Thecalling MSC is bridged to the called VMSC through the tone server thatintercepts the normal ring back tone sent by the VMSC and replaces the ringback tone with the user-defined ring back tone on the server. During theconversation, the tone server stays in the bridging state. When the callingMSCa cannot implement the service, the HLR instructs MSCa to route theservice to MSCb that can implement the service. MSCb initiates a route queryand connects the tone server to complete the subsequent functions.SS_CODE of called MSC connects the tone server to the caller who dialsa called party subscribed to the CRBT service, while sending alerting to caller.Then the tone server let the caller hear beautiful melodies while call waiting,Replacing boring "du du". If called party answers, GMSC/TMSC willdisconnect the link to the tone server. Then the calling party and called partycan communicate. During the conversation, the tone server doesn't stay in thebridging state.Using Intelligent Networking, it is possible to centralize such subscriberinformation on an external database away from the core switching platform,letting a CRBT service provider determine current subscribers. The WINALERTING PATTERN triggering flow is that: Firstly, register CRBTsubscriber's TCSI to trigger to RBT SCP in HLR. Secondly, when A call B,VMSCA will send SRI to HLR to get TCSI of B, and trigger to RBT SCP bysending IDP to RBT SCP. Thirdly, CRBT SCP will find that B is CRBTsubscriber, and will send SRI to HLR to get MSRN of B, and send CONNECTto MSC. The Called Party number of CONNECT message should be Prefix +B'MSRN. Foully, VMSCa will route the call the RBT system, RBT systemwill peel off the prefix and the true MSRN. First RBT system pages the calledparty, if the status is idle, RBT system will play RBT to calling party. Finally,if called party answers, CRBT system will stop playing CRBT. Then thecalling party and called party can communicate.Knowing as above, WIN ALERTING PATTERN is needed for every callaccessing the CRBT tone server. This is inefficient and can make the serviceunnecessarily expensive. When the connected SSP is able to support CAMELphase 4 Call Party Handling operations, it overcomes the need for trombonewhen implementing a CRBT service.This thesis mainly discusses the project and implementation of CRBTbase on CPH characteristic in Mobile Intelligent Network CAMEL phase 4.The following four aspects are discussed: the principle of CAMEL andCAMEL4, the solutions of CRBT based on MSC and CAMEL, the analysis ofCPH characteristic and the implementations of the new solutions of CRBTaccording to the development of CPH characteristic. Firstly, this thesisintroduces the principle of mobile communication, Intelligent Network,CAMEL and the new characteristics of CAMEL phase 4. Secondly itintroduces the solutions and system frame of CRBT. Thirdly it analyzes theCPH characteristic, the CAP operations (messages) of CPH and the messageflow of CPH operations. At last, it discusses the implementations of the newsolutions of CRBT according to the development of CPH characteristic insome kind of software switched MSC.The main works are:(1) By analyzing the protocol of CAMEL phase 4 and CPH, thedescriptions of CPH correlated character CAP operationSL,ICA, ML, DL and the handle flow are given.(2) Analyzing the current solution of CRBT, including NPI ofcalling MSC, SS_CODE of called MSC, and WINALERTING PATTERN based on CAMEL2. And There arequestions of wasting relay resource because of paging in IPin the solution of WIN ALERTING PATTERN based onCAMEL2 are mentioned.(3) Based on some kind of software switched MSC, the wholeframe of the CRBT solution in CPH is designed.(4) According to the module made by whole design, giving thedetailed implement of each module handling the CAPoperations, such as SL, ICA, ML and DL. Further more,analyzing the effort of each operation in the CRBT serviceflow. Last, the analysissitus picture is given.The technology realization CRBT using CAMEL phase 4 technologiesdiscussed in the thesis is under going, the project is meaningful to ourcountry's mobile communication technology reaching to the world's advancedlevel.