The word 'U' in 3G technology

The demand for higher data rates and security has led to many important changes in the popular GSM wireless standard. 3G network was born, entailing many technical problems such as USIM, USAT .

Technology experts tend to name the new application as an extension of the original term. This is the cause of many confusion, because if only looking, many will place GSM on par with UMTS, SIM with USIM, SAT with USAT and ICC with UICC.

The word 'U' appears in the new terminology which stands for Universal (global, popular). However, in these cases, U is understood as 'the ability to control more than one system ', not necessarily applications that cover the whole world.

UMTS - global mobile telecommunications system

The most talked about 3G technology in recent years is Universal Mobile Telecommunications System (UMTS), developed directly from GSM, but fiercely competitive with its own " grandfather ". " Universal " in UMTS means beyond European borders. The technology has a transmission speed of about 1,920 Kb / sec, supporting customers to download music, videos and group conferences . However, some recent survey results in Japan show the need to use video calls (video calls ) not really as high as expected.

As known, CDMA ( Code division multiple access ) technology is fiercely competing with TDMA (Time Division Multiple Access) in GSM network. However, UMTS, the "successor" of GSM, has separated from TDMA and uses W-CDMA, TD-SCDMA or TD-CDMA technology.

USIM and UICC

Universal Subscriber Identity Module (USIM) is an application of UMTS technology, operating on UICC smart cards in 3G phones. It contains user data, credentials and provides storage to save messages.

Universal Integrated Circuit Card (UICC) contains SIM in GSM phones and contains USIM in UMTS network. This smart card, usually several hundred KB in size, ensures the integration and security of personal information. Each UICC can include multiple applications, allowing access to both networks, saving contacts and running other applications.

Vodafone New Zealand UICC 25 x 15 mm card. UICC cards include CPU, ROM, RAM, EEPROM ( Electrically Erasable Programmable Read Only Memory - programmable and delete memory) and I / O circuits ( Input / output - I / O system). The first versions were 85 x 54 mm, but then dropped to only 25 x 15 mm.

USAT and USAT-I

USAT ( USIM Application Toolkit ) can be understood in two different meanings. In the first way, it is a natural transformation from the SAT in the GSM network when joining the ' U world '. USIM has the role of carrying out interoperability between the phone and the network, while basically, the USAT uses the phone to transmit commands or information between the user and the network.

However, this technology will have a completely different meaning if it is called USAT-I ( USAT Interpreter ). It is also an application of UICC, similar to USIM and USAT. The difference is that USIM in smart card memory is a single, fixed application and all of its operations are pre-defined by the 3G standard. USAT, also located in this memory, allows network operators to implement new services without having to follow the standard.

In contrast, USAT-I does not shape the mode of operation of an application, but a byte decoder. It handles any encoded program and passes through it like Java. Java tags allow loading and managing applets (small application programs that perform a specific task), while USAT-I supports loading and operating ' USATlet '. However, the applet is a permanent part of the smart card, while "USATlet" is only temporarily transmitted via a smart card and will be removed after the task is completed.

The forerunner of 3G is 2G phone system, like GSM, CDMA, PDC, PHS . GSM is then upgraded to GPRS, also known as 2.5G generation. GPRS supports 140.8 Kb / sec speed, although the common rate is only 56 Kb / sec. E-GPRS, or EDGE, is a significant step up from GPRS with data transmission capacity of 180 Kb / s and is classified into 2.75G system.

In 2006, the Japanese UMTS network will upgrade to HSDPA ( High Speed ​​Downlink Packet Access - Accessing data packets that connect signals from satellites to high-speed earth stations), considered as 3.5G networks, with speed. 14.4 Mbps. High-Speed ​​Uplink Packet Access - High-Speed ​​Uplink Packet Access - Access to data packets connecting signals from ground stations to high-speed satellites is also in progress.

Hai Nguyen