Program Of Taiyuan PS Domain On The Second Phase About China Mobile TD-SCDMA Network

With the third important recombing of Chinese telecom operators and the licenses for third generation (3G) mobile networks being awarded to three telecom operators, 3G has truly come into our life. China Mobile got a license to deploy 3G networks based on TD-SCDMA, a home-grown 3G standard. TD system can provide not only traditional voice and data service, but also characteristic services of 3G, such as enhanced data card, Multimedia Ring Back Tone , mobile TV, video phone service. Along with the more need of data service, more requests of PS domain core network are brought forward.Taiyuan is one of the cities of China Mobile TD-SCDMA network of the second phase. In accordance with the integration of development goals of CMCC's 2G/3G mobile core network, the overall demand for GPRS and TD PS domain services business by the end of year 2009 in whole Shanxi province will be taken into account. We carried out the planning and construction programming of Shanxi Province core network PS domain.I was one of the designer of Taiyuan city PS domain on the second phase of China Mobile TD-SCDMA network (Including TD Node-B, RNC, core network CS domain, core network PS domain). I have taken part in the program of project all the way. TD-SCDMA core network PS domain is a relatively new field for communication design. I understood step by step TD-SCDMA core network PS domain theory, key technology, system features through collecting a lot of relevant information. I summarized TD-SCDMA core network planning features by comparing the characteristics of GPRS network planning, to guide the task to undertake TD core network planning practices. On top of it, we gained a certain research methods on the PS domain program, summed up a set of effective methods, and improved my skills through the process.The program and construction project of PS domain system is a very complex and systematic work. It includes that: development forecast of users, traffic forecast, construction principles, compared and choice of project. The development forecast of users bases on the history data and the new characteristic of TD operation. The result is the attached numbers and activated PDP numbers of PS domain in programming period. Traffic forecast bases on the development forecast of users. Refering to the user's business model, we estimate all kinds of traffic, such as interface of Gb, Iu-PS, Gn, Gi. We can estimate the incremental traffic of core network by the actual state of GPRS. The construction principles are often provided by telecom company, but we also should take the features of our own network. At last we can make the choice of network programming based on the above methods, also based on the selection for the producer and price of the equipment.This study based mainly on existing technical knowledge and planning methods to solve the new problems of communication project. Because the 3G core network in China has just started, there may be less information to refer. We have to study the experience in other network planning. With 3GPP R4 version for network PS domain core network planning can refer to GPRS core network.We must first develop or understand its construction principles for core network planning. We know that China Mobile using 3GPP R4 version in the 3G core network. The R5 version of the IMS network has just begun construction of small-scale trial network. There are two modes for R4 PS core network construction: fusion method and the separate construction method. Fusion method means that 2G and 3G packet core network construction confluently. We need to upgrade the software and hardware of existing GPRS network in the SGSN, GGSN equipment, to support the Iu-PS interfaces, so the users can access 3G system. Separate construction mode refers to construct new PS of R4 network alone. Construct new SGSN, GGSN and other equipment independently, 2G/3G customer service is provided respectively by 2G and 3G networks. The two modes have their advantages and disadvantages. From the development trend of telecommunication technology, the development of the core network of GPRS and PS in 3G is exactly the same, and the standard is fully integrated, so, the merging scheme in the view of technology has no problem. From TD-SCDMA II, China Mobile Group has unified the construction ideas, asking that CS and PS of core network in each province should use the way of updating the existing 2G equipments, in principle, it's not allowed to add new equipment privated of TD-SCDMA in core network. Some elements of the existing 2G network should upgraded, so as to achieve the amalgamation of 2G and TD core network.The two most important network elements of core network PS domain are SGSN and GGSN. The key indicators for measuring the capacity and capability of SGSN and GGSN equipment are the attached numbers and the PDP activation numbers of users. We meet for the network planning of the short-term or long-term, we need to know these two data predicted in the future, not the history status, therefore, the development forecast of users should be necessary. For users in the development of prediction, we often use a simple average growth rate forecast, the average growth rate by historical data to measure. In fact, the method is very rough. You should use a more scientific approach to mathematical modeling to predict.For the data predictions based on time sequence, such as user development predictions in communication engineering, the predictions of a service's using average and so on, having a certain amount of historical time point statistical data, we can use the trend extrapolation algorithm to predict. In real time sequence, the distribution of each time point development level is fluctuating, Using mathematical formulas, according to each time point development level, drawing a smooth trend line to make the sum of squares between actual value and estimation value (theoretical value) in trend line smallest. The trend line can be a straight line or a curve line. Generally, we can draw the scatter diagram of time sequence in rectangular chart to observe the graphical features. We can also calculate some relevant index according to the experience to make probably sure the diagram of time sequence. Such kinds of trend extrapolation algorithm of time sequence have three common forms: linear fitting equation, conic (parabola) fitting equation and exponential curve fitting equation. To verify the accuracy of the prediction models, we need to undertake necessary tests. Normally, we use the method of variance analysis to compare the coefficient of determination (R2). The more R2 approaching to 1, the best the curve fitting degree, then, we can get the best fitting curve.In this paper, using historical data of 19 months's measured average peak number of subscribers and PDP activated subscribers, through comparison and analysis of math methods, and finally, we choosed exponential curve fitting equation and predicted the subscriber data before the deadline ( by the end of 2009). On this basis, combining with the user model, SGSN, GGSN, DNS and CG device configuration in Taiyuan were calculated and analysed. Finally, the conclusion of this project is: constructe of 3 sets SGSN, 4 sets of GGSN, 2 sets of CG, 1 set of DNS, and cut over and adjust the exsiting equipment.As the designer of the project, I'm responsible for studying the construction scheme, and providing the optimization scheme for the construction unit to achieve the targets of the minimum cost and the best network performance. In the mean while, the planning scheme and process in PS construction of TD project can provide examples and reference for subsequent engineering of China mobile and for the similar network of mobile telecom carriers, and accumulate experience for the development of TD-SCDMA core network .