All-IP Based CDMA2000 1xEV-DO Mobile Communication System

ZTE’s CDMA2000 1xEV-DO mobile communication system adopts advanced CDMA2000 1xEV-DO technology that is optimized for high rate wireless data services. The system features:

• full compatibility and smooth upgrade,
• large capacity and high integration,
• all-IP based architecture,
• wide coverage,
• reliable network,
• flexible networking.
  

Deployment of ZTE’s CDMA2000 1xEV-DO system on the basis of the CDMA2000 1X network is an effective means for operators to provide better data services and create new revenue-generating opportunities.

CDMA2000 1xEV-DO is an advanced technology optimized for high rate wireless data services that are characterized by burstness, high speed, asymmetric uplink and downlink data rate, and insensitiveness to time delay.  It has the following advantages:
    (1) Data Optimization
    CDMA2000 1xEV-DO, a data-optimized version of CDMA2000, delivers a forward peak data rate of up to 2.4576 Mb/s within a 1.25 MHz carrier, providing higher spectral efficiency than GPRS, CDMA2000 1x and WCDMA.

    (2) Backward Compatibility
    It is compatible with CDMA2000 1X by employing the same Packet Control Function (PCF) and Packet Data Serving Node (PDSN).

    (3) Mature Technology
    It is a field-proven technology capable of providing a variety of standard interfaces. It has been put into commercial applications in countries like Korea and Japan.

1 ZTE´s CDMA2000 1xEV-DO Solution

1.1 Network Architecture
ZTE´s CDMA2000 1xEV-DO mobile communication system features full compatibility, large capacity, high integration and a full range of products. It is integrated with CDMA2000 1X in system design, allowing mixed insertion of channel cards in the same base station. In practice, carriers of CDMA2000 1X and CDMA2000 1xEV-DO can be flexibly configured to meet specific requirements. Shown in Figure 1 is its network structure.
ZTE’s CDMA2000 1xEV-DO system comprises the Mobile Station (MS), Base Transceiver Station (BTS), Base Station Controller (BSC), Packet Control Function (PCF), Packet Data Switching Node (PDSN) and AAA. It employs IP-based network architecture with which the ANSI 41 core network is no longer needed. The equipment´s interfaces include the air interface, A8/A9 interface, A10/A11 interface and A12/A13 interface. The
A8/A9 and A10/A11 interfaces have the same features as those of the CDMA2000 1X. The A12/A13 are new interfaces. Connecting the Access Network (AN) and AN AAA for transfer of only signaling, the A12 interface fulfills AN-level authentication, and at the same time, the AN AAA sends back the Mobile Node Identifier (MNID) needed by the Access Terminal (AT) at A8/A9 and A10/A11 interfaces. Also serving as a signaling interface, the A13 fulfills AT related information exchange during handoff between different ANs.

1.2 System Features
    (1) Full Compatibility and Smooth Upgrade 
    ZTE’s CDMA2000 1xEV-DO system achieves perfect cross-carrier channel sharing inside the BTS, and its external interfaces are independent of the standards. The system supports mixed insertion of channel cards of different standards in the same BTS, thus ensuring full compatibility and smooth migration of CDMA2000 1X to 1xEV-DO and 1xEV-DV. ZTE’s solution for smooth migration among the CDMA2000 family is illustrated in Figure 2. The system makes full use of the existing network resources to protect the operator’s initial investment. And the superior system design provides a gradual fallback mechanism in the process of upgrade to guarantee the network security. 

    (2) Large Capacity and High Integration
    ZTE’s CDMA2000 1xEV-DO Base Station Subsystem (BSS) can support a maximum of 2 500 000 voice subscribers (0.02 Erl/sub) and above 6 Gb/s data services. Since network processors and the latest Digital Signal Processing (DSP) and CPU technologies are widely used, the system integration is increased significantly. A single BSC shelf can serve as a BSC office, and dual shelves support over 60 000 subscribers. A BSC rack supports more than 100 000 subscribers. The centralized BTS architecture can effectively reduce the operator’s O&M cost. A single macro-BTS digital shelf provides up to 24 carrier-sectors capacity, enabling channel sharing of the Cell Site Modem (CSM) within the 24 carrier-sectors. A single RF shelf is able to support a maximum capacity of 8 carriers 3 sectors or 4 carriers 6 sectors.

    (3) All-IP Based Architecture
    ZTE is one of the earliest manufacturers to adopt all-IP architecture in the 3G networks. Inside ZTE’s CDMA2000 BTS and BSC, modules communicate with each other by IP. For interconnection between network elements of CDMA2000, both IP and ATM transfer are supported. But the IP transfer has proved more efficient and is strongly recommended. With all advantages offered by all-IP technology, all-IP CDMA2000 equipment can be smoothly converged into future communication networks.

    (4) Wide Coverage
    ZTE’s "Super BTS", as shown in Figure 3, is made up of one master baseband unit and four slave baseband units. It can provide up to 120 carrier-sectors within a single site. A remote Radio Frequency Subsystem (RFS) in it can cover the same area that once took a dozen of conventional BTSs. As the remote RFS can be installed outdoors, only one BTS room is necessary in the coverage area, which will greatly reduce the operator’s cost. Additionally, its powerful baseband processing part can be located in the same place as the BSC for easy maintenance and cost savings.

    (5) Reliable Network
    ZTE’s CDMA2000 1xEV-DO system adopts RF and Abis ring networking technologies, as shown in Figure 4. Either the macro-BTS or the micro-BTS can be connected to multiple indoor/outdoor remote RF units. Topology of the base-band and RF units can be star, chain, or even ring with higher reliability. A single RF ring supports up to 24 remote RF modules. Abis interface between the BSC and the BTS supports star, tree, and ring connections. As both the Abis and the baseband RF support ring networking, a more reliable network can be ensured.

    (6) Flexible Networking
    The system provides a series of BTS products such as macro, micro and compact BTS, ultra-far coverage BTS and remote RF extended module. The frequencies supported can be 450 MHz, 800 MHz, 1.9 GHz, 2.1 GHz and so on. ZTE can deliver a total CDMA2000 1xEV-DO solution.

• It can meet the operators’ various requirements: high-level or low-level configuration, large capacity but small coverage (for urban areas), small capacity but wide coverage (for suburban areas), etc.
• It has a series of products that are complementary to each other, and effectively combined to optimize network quality and improve performances.
• Its BTS series has general-purpose modules, which is convenient for the operator’s future maintenance.
• The system adopts building block structure to satisfy the operator’s need for capacity expansion at any time.
• It can converge with the WLAN system to improve the network quality.

2 Market Applications and  Future Prospects
ZTE is the first company in China to develop a successful CDMA2000 1xEV-DO mobile communications system. On June 10, 2002, ZTE launched it at the Hong Kong 3G Summit and demonstrated wireless data services with rates of up to 2.4 Mb/s. At present, the system can meet the requirements for large-scale commercial application.
According to the actual application situations and service incomes of worldwide CDMA network operators, the current business is still dominated by the voice service. However, mobile data services have great growth potential  in the future. As the penetration of mobile phones increases, it is a tendency for the operator to have a decreased ARPU (Average Revenue Per User). Therefore, all operators are devoted to launching a variety of value-added services for the decrease of ARPU value. With the growing demands for high-speed wireless data services, the CDMA2000 1X network can no longer meet the demands in certain hotspot. The deployment of the CDMA2000 1xEV-DO network is an effective means for operators to provide better data services and create more revenues. The market demands offer a promising prospect for CDMA2000 1xEV-DO applications. CDMA2000 1xEV-DO systems have currently been put into mature commercial applications in countries such as Korea, Japan and America.
ZTE’s CDMA2000 1X system has a wide range of commercial applications around the world. Following the CDMA2000 1X, ZTE rolls out its CDMA2000 1x EV-DO, an all-IP based 3G system featuring superior performances and technical advantages. ZTE is able to deliver a tailored total solution to the CDMA2000 1xEV-DO system, helping operators deploy reliable and elaborate 3G networks, and improve their market competitiveness. ZTE’s CDMA2000 1xEV-DO system is bound to enjoy a promising market prospect.

Manuscript received: 2004-06-30