Position of iBSC in Network

When TC is internal, the position of ZXG10 iBSC (V6.20) in the

network is shown in Figure 1.

When TC is external, the position of iBSC in the network is shown in Figure 2.

 ZXG10 iBSC (V6.20) is a part of GERAN (the GSM/EDGE Radio Access Network). GERAN includes one or multiple BSSs, and one BSS consists of one BSC and one or multiple BTSs. BSC is connected with BTS via Abis interface, and BSC-BSC, BSC-RNC are connected with each other via Iur-g interface. If TC is internal, GERAN is connected with GSM/UMTS Core Network via A/Gb/Iu interface. GERAN has two working modes: A/Gb mode and Iu mode and can work in these two modes at the same time. In this case, the 2G MS uses A/Gb working mode, the working mode used by the MS supporting Iu mode depends on GERAN and MS together.

3GPP Standard Development Status

3GPP standard versions include R99, R4, R5, R6 and R7. R99 version was frozen formally in Mar, 2000, and refreshes once every three months. Current commercial version of R99 is based on the version of June, 2001, for in later version, the number of CR is decreasing rapidly and there are no larger modifications and non-compatible upgrade.

R4 version was frozen in Mar, 2001. It passed in Mar, 2002 and is stable currently. R5 version was frozen in June, 2002 and is stable currently. Most R5 versions that providers support are the version of June, 2004. R6 version was frozen in June, 2005 and may be stable in a year. At present, R7/LTE has started up and its functional features are still in initial phase.

R99 and R4 versions are put into commercial use maturely. R6 version protocols are in developing status.

WCDMA Technical Standards Development Trends

WCDMA was originated by standardization organizations and manufacturers in European countries and Japan. WCDMA inherits the high standardization and openness of GSM, and its standardization progresses smoothly. WCDMA is the third generation mobile communication standard developed by 3GPP, with the GSM MAP as its core and UTRAN (UMTS Terrestrial Radio Access Network) as its wireless interface. Using the chip rate of 3.84 Mbps, it provides data transmission rate up to 14.4 Mbps within 5 MHz bandwidth.

The WCDMA technology has the following characteristics:

1. Supporting both asynchronous and synchronous BTSs, for easy and flexible networking 
2. Using QPSK modulation mode (the HSDPA services also use the 16QAM modulation mode) 
3. Using pilot assisted coherent demodulation 
4. Accommodating transmission of multiple rates, and implementing multi-rate and multimedia services by changing the spread spectrum ratio and using multi-mode concurrent transmission 
5. Rapid and efficient power control of uplink/downlink greatly reduces multiple access interference of the system, but increases the system capacity while reducing the transmission power. 
6. The core network is evolving based on the GSM/GPRS network, and maintains compatibility with the GSM/GPRS network. 
7. Supporting soft handover and softer handover, with three handover modes, inter-sector soft handover, inter-cell soft handover, and inter-carrier hard handover

Overview Technology of WCDMA in 2012

The 3rd Generation Mobile Communication System (3G) is put on agenda when the 2nd generation (2G) digital mobile communication market is booming. The 2G mobile communication system has the following disadvantages: limited frequency spectrum resources, low frequency spectrum utilization, and weak support for mobile multimedia services (providing only speech and low-speed data services). Also, thanks to incompatibility between 2G systems, the 2G mobile communication system has a low system capacity, hardly meeting the demand for high-speed bandwidth services and impossible for the system to implement global roaming. Therefore, the 3G communication technology is a natural result in the advancement of the 2G mobile communication.

As the Internet data services become increasingly popular nowadays, the 3G communication technology opens the door to a brand new mobile communication world. It brings more fun to the people. In addition to clearer voice services, it allows users to conduct multimedia communications with their personal mobile terminals, for example, Internet browsing, multimedia database access, real-time stock quotes query, videophone, mobile e-commerce, interactive games, wireless personal audio player, video transmission, knowledge acquisition, and entertainments. What more unique are location related services, which allow users to know about their surroundings at anytime anywhere, for example, block map, locations of hotels and super markets, and weather forecast.

The 3G mobile phone is bound to become a good assistant to people’s life and work. The 3G mobile communication aims at meeting the future demand for mobile user capacity and providing mobile data and multimedia communication services. Initially, mobile communication technologies were developed separately, as various countries and technical organizations continued to develop their own technologies. Thus, the USA has Basic Technology of WCDMA 2 Confidential and Proprietary Information of ZTE CORPORATION AMPS, D-AMPS, IS-136, and IS-95, Japan has PHS, PDC, and the EU has GSM. On one hand, this situation helped to meet the needs of the users at the early stage of mobile communication and expand the mobile communication market. On another hand, it created barriers between the regions, and made it necessary to unify the mobile communication systems globally. Under such a context, ITU launched the standardization of the 3G mobile communication system in 1985.

The 3G mobile communication system, IMT-2000, is the general term for the next generation communication system proposed by ITU in 1985, when it was actually referred to as Future Public Land Mobile Telecommunications System (FPLMTS). In 1996, it was officially renamed to IMT-2000. In addition, the 3G mobile communication technology extends the integrated bandwidth network service as far as it can to the mobile environment, transmitting multimedia information including high quality images at rates up to 10 Mbps.

Compared with the existing 2G system, the 3G system has the following characteristics as summarized below:

1. Support for multimedia services, especially Internet services 
2. Easy transition and evolution 
3. High frequency spectrum utilization 

Currently, the three typical 3G mobile communication technology standards in the world are CDMA2000, WCDMA and TD-SCDMA. CDMA2000 and WCDMA work in the FDD mode, while TD-SCDMA works in the TDD mode, where the uplink and downlink of the system work in different timeslots of the same frequency.

The 3G mobile communication is designed to provide diversified and high-quality multimedia services. To achieve these purposes, the wireless transmission technology must meet the following requirements:

1. High-speed transmission to support multimedia services 

• Indoor environment: >2 Mbps
• Outdoor walking environment: 384 Mbps 
• Outdoor vehicle moving: 144 kbps 

1. Allocation of transmission rates according to needs 
2. Accommodation to asymmetrical needs on the uplink and downlink 

In the concept evaluation of the 3G mobile communication specification proposals, the WCDMA technology is adopted as one of the mainstream 3G technologies thanks to its own technical advantages.

System Background of ZXG10 iBSC (V6.20)

GSM, as the second generation mobile cell communication system, voice service as primary one, has been extensively applied. But with the development of mobile communication technology and diversity of service, demands on mobile data service is increasing.

Demands on data service is more urgent than before, along with the demands increased for GSM
equipment, including IP Gb interface, Iu interface merge, mass capacity data interface, and merge with 3G service. To meet above demands, ZTE developed ZXG10 iBSC (V6.20) independently.