User identification card (UIM) and air activation Technology (OTA) in CDMA Systems)

From: China Mobile Communication Forum

I. CDMANetwork

China Unicom announced the large-scale development of CDMA networks and explicitly proposed the implementation of SIM card functions similar to the GSM system in the CDMA system. This action immediately aroused strong repercussions at home and abroad. In China, many people argue over the advantages and disadvantages of the SIM card (called uimcard in CDMA systems) and the air activation Technology (OTA) in CDMA systems.

We know that mobile devices (terminal devices) are directly oriented to end users. The performance, price, style, and even color requirements for mobile devices vary widely. If a carrier directly sets up a sales outlet to sell a mobile station, it needs to invest a lot of money in advertising, the establishment of a sales outlet, and maintenance, and bear the market risks of the Mobile Station. In today's increasingly clear social division of labor, operators want to focus on selling mobile communication services and hand over the sales of mobile terminals to equipment manufacturers or sellers. The user identification card (UIM) and air activation Technology (OTA) in CDMA systems are technologies generated to achieve this purpose.

 

IIUser identification card (UIM)

In the original design of the CDMA system, user identification information is directly stored in mobile terminals, and there is no functional entity that can be separated from mobile terminals to store user information. Although some operators and manufacturers hope to have a SIM card similar to the SIM card in the GSM system in the CDMA system to achieve device card separation, this idea has not become the mainstream idea. It was not until China Unicom declared that it wanted to implement SIM card functions on CDMA mobile phones that it had greatly accelerated the process of implementing uimcard in CDMA systems. The UIM card standardization work is carried out by PP2 (Third Generation Partner Program 2. At present, this work has been completed.

According to the uimcard standard, the uimcard of the CDMA system will adopt the same physical structure, electrical performance and logical interface as the GSM system. Based on the SIM card, according to the requirements of the CDMA system, add related parameters and commands to implement the functions of the CDMA system. In other words, a UIM card can be understood as a function extension of the SIM card for the CDMA system. Figure 1 describes the file structure of a UIM card supporting multiple systems. Through this figure, we can clearly understand the relationship between the UIM card of the CDMA system and the SIM card of the GSM system.

The information storage structure of the entire multi-mode uimcard is very similar to the file storage structure of the computer. In Figure 1, the preceding two directory files are related to the usage of the GSM system, including pcs1900. The following information is required by the CDMA system. This Protocol is further expanded to support other cellular technologies in North America, such as D-AMPS, as shown on the left of the lower layer. In other words, both SIM card and UIM card are based on the IC card technology. Different cellular systems store information related to their own systems in the IC card.

The information stored in the UIM card in the CDMA system can be divided into three types:

First, the user identification information and authentication information, mainly imsi number and CDMA system proprietary authentication information, including a-key, SSD-A and SSD-B.

The second type is business information. business-related information in the CDMA system is stored in HLR. There are not many such information in the UIM card, mainly including short message status and other information.

The third category is information related to the work of the mobile station, including the preferred system and frequency band, the ID of the attribution area (SID, NID group) and other parameters. In addition to the above information to ensure the normal operation of the system, you can also store your own information, such as the phone number book, in the UIM card.

In this way, the CDMA system can release the sales of mobile stations like the GSM system, so that users can freely choose different types of mobile stations. The operator operates in the same way as the GSM Operator, and only needs to set up a sales outlet to sell uimcards.

 

3.Air activation technology OTA

Air activation is one of the original designs of CDMA systems. From a technical point of view, air activation is an Air Code Writing Technology. This technology uses an air interface to input the information required for normal operation of the mobile station to the mobile platform. From a service perspective, the air activation technology is a means of selling telecommunication services. The operator using this technology allows users to use their own computers to access the network. After purchasing a mobile device, the user can call the mobile device to access the center of the operator and inform the service personnel of the service type. After confirming the user's needs, the service personnel, use OTA technology to write necessary information to the mobile station through an air interface. Then, you can use the newly added services normally. Figure 2 is a simplified OTA execution process.

The basic process for a new user to activate the service using OTA is as follows:

1. A new user first calls a special number (for example, * fc XX) using the phone he purchased ). FC indicates the specific service number, which is Ota. XX indicates the System Selection code. You can use it to select an operator.

2. The mobile station analyzes the number and executes OTA according to the requirements of the FC user. The mobile station re-searches the CDMA channel based on XX, registers in the network of the selected operator, and initiates a call.

3. msc sends the call to the Customer Service Center.

4. The service personnel respond to the call and understand the user's business needs and payment methods.

5. After confirming the user information, the system starts to automatically input data to the mobile station. This process may include understanding mobile station capabilities, starting encryption to ensure the security of subsequent data transmission, transmitting user identification information, initializing authentication information, and related roaming information and other data.

6. After the above data is successfully transmitted, the user can end the call and reactivate the mobile device. Mobile communication, home of Communication Engineers, communication talents, job recruitment, network optimization, communication engineering, travel and accommodation, and blacklist of communication enterprises.

 

Four OTAAnd UIM

OTA technology writes information to the mobile station through the air interface, which is necessary to ensure the operation of cellular information. The information is basically the same as the information stored in the UIM card. Of course, the information stored by the user (such as the phone number and code book) cannot be input to the mobile station through Ota, which is also a disadvantage of Ota, because the user had to re-enter his phone number book when changing the phone number.

In general, both the user identification card (UIM) and the air activation Technology (OTA) can achieve the separation of telecommunications services and telecommunications terminals. With the support of these two technologies, users can purchase mobile phones from any mobile terminal vendor. Therefore, users can freely choose features, prices, and appearances of mobile phones based on their interests; manufacturers can directly sell products to users without going through the intermediary of operators. operators can also reduce the costs and risks of mobile phone sales. This is undoubtedly beneficial to all parties.

In addition, because the two technologies have different implementation methods, they are suitable for different social backgrounds.

China Mobile and China Unicom have already adopted the GSM technology. Although operators still need to invest in establishing a certain number of sales outlets to sell uimcards, operators have already established these network points when operating the GSM network, so this is not a new investment.

Although OTA technology allows operators to establish as few sales outlets as possible, its implementation is based on an efficient customer service center. This is one of the biggest differences between operators in China and those in the United States. Our operators are still weak in the Construction of customer service centers. In addition, because users connect to the Customer Service Center by phone, they can only use credit cards as the payment option, and the credit card penetration rate is not high in China. At the same time, the UIM card also has other additional functions, such as storing the phone number book or short message. It is especially convenient to change the mobile phone and can borrow others' mobile phones. These features are quite impressive and conform to the user's habits in China.

Therefore, we can say that uimcards are more suitable for China's national conditions, while OTA technology is more suitable for American operators.