ZTE´s WiMAX System and Technologies

WiMAX technologies contain IEEE 802.16-2004—the fixed broadband wireless access technology, and IEEE 802.16e—the mobile broadband wireless access technology.

    To meet users´ different requirements, ZTE´s WiMAX system can operate in various frequencies bands such as 2.3, 2.5, 3.3, 3.7, 5.0, and 5.8 GHz. It also supports 1.75, 2.75, 3.5, 5, 7 and 10 MHz channel bandwidth.
ZTE´s WiMAX system satisfies the need of fixed, portable and nomadic applications, and can be upgraded to support simple mobile and full mobile applications.

More information at:
http://wwwen.zte.com.cn:8080/English/03product/

WiMAX stands for Worldwide Interoperability for Microwave Access. It was put forward to promote the commercialization of the IEEE 802.16 standard. Nowadays WiMAX becomes a popular name of the IEEE 802.16 standard.

    The WiMAX wireless access technologies are the fixed broadband (IEEE 802.16-2004) and the mobile broadband (IEEE 802.16e) technologies. The system in compliance with the IEEE 802.16-2004 standard generally provides transmission distances ranging from 5 to 10 km, achieving a maximum distance of 50 km and a maximum rate of 75 Mb/s.The system can connect portable or fixed terminal users to the Internet, and also connect offices, homes and other environments to the wired backbone. Moreover, it can serve as Wireless Local Area Network (WLAN) hotspots and backhaul links of 2G and 3G base stations. Therefore， the system is considered as a wireless extension for the cable and Digital Subscriber Line (DSL).

    The system in compliance with IEEE 802.16e can provide broadband wireless access for roaming/mobile users. Roaming/mobile data services are deployed by operators through broadband wireless devices such as notebook PC, PDA and handsets. As the WiMAX technology is getting maturer, the WiMAX-based system will become the mainstream in the Broad Wireless Access (BWA) industry.

1 ZTE´s WiMAX System
In response to the explosive growth of WiMAX technologies, ZTE rolls out its new generation broadband wireless access system that fully supports the IEEE 802.16/WiMAX family of standards. The WiMAX system is designed for fixed, nomadic, mobile and roaming applications. It provides wireless data access for fixed and roaming users. It supports IP, VoIP, and E1 services, helping operators build a brand new service operation platform.

1.1 System Constitution
To meet users´ different requirements, ZTE´s WiMAX system can operate in various frequency bands such as
2.3 GHz, 2.5 GHz, 3.3 GHz, 3.7 GHz, 5.0 GHz, and 5.8 GHz, and support 1.75 MHz, 2.75 MHz, 3.5 MHz, 5 MHz, 7 MHz and 10 MHz channel bandwidth. It is made up of three parts: Base Station (BS), Subscriber Station (SS) and Network Management System (NMS), as shown in Figure 1.

1.2 System Features
ZTE´s WiMAX system has the following features:

• It adopts the IEEE 802.16 standard to ensure interoperability with other WiMAX systems or products.

• It provides the QoS policy based on service flows.

• It supports BS power control to meet the requirements of large-scaled networking, and supports the

    Automatic Transmit Power Control (ATPC) function of all terminals.

• It supports SNMP V2-based centralized NMS, telnet CLI NMS, and local RS232 NMS.

• The NMS provides complete management functions including configuration management, fault management, performance management, and security management.

• It provides remote software download and upgrade function.

• It supports authentication and authorization for terminals.

• The BS supports flexible configuration and meeting different requirements of operation.

• It supports a perfect transmission encryption mechanism to greatly improve system security.

• It adopts network architecture specified by the WiMAX organization, and complies with European Telecommunications Standards Institution (ETSI)，HiperMAN and Wireless Metropolitan Area Network (WMAN) standards.

• It enables seamless convergence with other wireline/wireless networks and the existing Authentication Authorization Accounting (AAA) platform.

• It provides high data throughput and large capacity, with one channel supporting a maximum of 512 CPEs.

• It adopts Orthogonal Frequency Division Multiplex (OFDM) modulation to improve anti-interference and wide coverage capability, and supports Non-Line-of-Sight (N-LoS) coverage ability, with the coverage radius ranging from 1 to 5 km.

• It supports adaptive modulation technology to automatically adjust the modulation mode based on the signal quality and to increase the distance of data transfer.

• The BS supports backhaul function.

• It provides four service types such as UGS, rtPS, nrtPS and BE, fully supporting data, voice, DDN dedicated line, and other service applications.

• It provides powerful upgrade capability, supporting upgrade to nomadic mode, and even to
  mobile/roaming mode.

• It offers a full range of product series, meeting operators´ requirements for different services and applications.
  

2 ZTE´s WiMAX Solutions
ZTE´s WiMAX system complies with the WiMAX specifications. The need of fixed, portable and nomadic applications is satisfied, and can be upgraded to support simple mobile and full mobile applications.

2.1 Fixed Application Solution
In addition to data, voice and video services, the fixed applications of the BWA system in the current market also involve Internet access, VoIP, VPN, and video monitoring. By virtue of integrated services access capability, ZTE´s WiMAX products can meet the demands for all these services, and deliver total service solutions.

    (1) Phone Bar (Long-distance IP Phone Supermarket)
    IP telephone supermarket refers to phone business halls set up in places with a large floating population such as shopping malls, scenic spots, railway/bus stations, schools, hospitals and crowded streets. Each business hall is equipped with several or dozens of telephones, and has a hot billing device and a printer that can immediately output call bills and control users´ call charge.

    The IP telephone supermarket provides users with quality service through clear and low-cost IP
long-distance voice.

    WiMAX products can deploy long-distance IP supermarket services in VoIP mode. The VoIP access solution adopts the Packet Switching (PS) based VoIP technology to complete a call. Firstly, the calling party´s analog voice signals are packed into IP packets for access to the IP network by using BWA technology. Then these IP packets are sent to the VoIP gateway at the network side, and converted back to analog voice, which is finally sent to the called party via PSTN. The VoIP access-networking diagram is shown in Figure 2.

    In order to deliver voice service, the IP pay phone business hall is equipped with an IP voice gateway to provide analog voice interface for access to the phone set. ZTE´s WiMAX system supports high priority for IP voice service to meet the delay requirement. The IP voice gateway converts analog voice signals into IP data packets for access to the SS via the 10/100 Mb/s Ethernet interface. Then the SS transmits them to the BS via the wireless mode. At the BS side, these IP data packets are converted back to analog voice signals via the voice trunk gateway. Finally, these voice signals are sent to the telephony switch via the E1 interface. In addition, a billing terminal is placed in the business hall to implement service management and real-time billing. It deals with incoming and outgoing call service via the IP voice gateway.

    This solution is characterized by simple network architecture, little change to the existing network, low investment cost, fast network construction and quick Return On Investment (ROI). Therefore, it plays an important role in protecting operators´ investments.

    (2) Video Monitoring
    With the rapid development in urban infrastructure construction, video monitoring system has found growing applications in fields such as environment protection, transportation, public security, electric power and oil industry. These applications can greatly alleviate shortages of management manpower and means. Moreover, the video monitoring system can record video in various preset modes, make a snap shot, and have the video played back or printed. It provides evidences in supervising polluting sources and controlling traffic flow, making possible the remote control over pollution and city traffic. The solution for video monitoring service is shown in Figure 3.

    This solution is applicable for video monitoring access to major polluting enterprises. It provide the access equipment of the video monitoring system, via which video monitoring signals are connected to the data MAN, and then transmitted to the environment monitoring center through the MAN transmission equipment. Connection in the above schematic diagram of video monitoring system is described in the followings:

• The video monitoring equipment collects image signals of the major polluting enterprises, and connects to the 3.5G subscriber station via the E1 interface.

• The 3.5G system allocates time slots of the radio channel to the remote station to meet the 1-2 Mb/s bandwidth requirement for video signal transfer. 

• The 3.5G subscriber station is connected to the BS via the air link.

• The BS is connected to the MAN transmission equipment via the E1 interface.

• Video monitoring signals are connected to the MAN via the 3.5G system.

• Video monitoring signals are transmitted through the MAN and then connected to the environment
  monitoring center.

• The system equipment at the environment monitoring center converts video monitoring signals back to image display of the major polluting enterprises.

2.2 Portable and Nomadic Application Solution
Portable and nomadic applications are divided into trusted and untrusted area as shown in Figure 4. In the trusted network solution, the enterprise builds its own WiMAX network to provide coverage. As a supplement to the existing network, the WiMAX network can help the enterprise deliver basic data services. The enterprise´s WiMAX users are not authenticated (bound on MAC address), or authenticated for its user name and password. The information security is guaranteed through various encryption modes. This solution can tell enterprise users from visiting users who are not allowed to access the internal enterprise applications. In the untrusted network solution, the WiMAX network is equivalent to an external enterprise network in respect of security. Users can not access the enterprise network until being strictly authenticated. Data are transferred in encrypted mode, and users may access safety part of the enterprise network via VPN mode. Therefore, information security for enterprise users is guaranteed via the VPN data encryption. This solution can also tell enterprise users from visiting users who are not allowed to access the internal enterprise applications. In terms of safety, both the user ID authentication and the encrypted air transmission are adopted. For the networking solution, an ASN-GW shall be added to the original enterprise network to perform access control and make sure that only legal users can access the enterprise network. At the same time, the 802.1x authentication shall be adopted.

3 Benefits of ZTE´s WiMAX Solutions

3.1 End-to-end Service Solution
    (1) An Integrated Solution to Wireline and Wireless Networks
    The system adopts the packet, open and layered all-IP network structure. It achieves seamless convergence of wireline and wireless networks, and delivers a variety of operation solutions.

    (2) Supporting Data, Voice and IP Video Services
    The system supports four types of service including UGS, rtPS, nrtPS and BE, fully meeting the demand for various services such as T1/E1, VoIP, VoD, FTP and Internet browse. It delivers data, voice and IP video services in the same network. For E1 transmission, it provides low end-to-end delay to meet the requirement on delay and jitter.

    (3) Complete QoS Solution
    The service types UGS, rtPS, nrtPS and BE correspond to different QoS parameters. Therefore, all these service types have their own complete QoS solutions. The system supports TOS-based priority and VLAN-based priority policies to guarantee normal transfer of data or circuit services of different priorities. In this way, the system can make full use of wireless network resources and meet the requirements for various operations.

3.2 Full Ranges of Product Series
    (1) Macro-BS, Compact BS and Enhanced Macro-BS
    The macro-BS provides the solution for users´ N-LoS data service access, and supports adaptive modulation. The enhanced macro-BS supports indoor coverage, nomadic applications and smooth upgrade to the IEEE 802.16e system. The compact BS employs the sub-rack other than the cabinet to support a carrier/sector. When few carrier/sectors (usually one to four carrier/sectors) are needed, the compact BS can effectively save operators´ investment. It is quite applicable for residential service access when combined with wired equipment and applicable on occasions where few carriers are needed or there is a limited installation space on the rack.

    (2) Outdoor/Indoor Multi-service Terminals
    A variety of outdoor/indoor terminals for multiple services such as data, voice, WLAN, VPN and TDM can meet the requirement for different applications and different levels of operations.

3.3 Low-cost Solution
    (1) IP-based Network Architecture to Low Network Construction Cost
The all-IP based network architecture allows easy interconnection with other equipment. ZTE´s WiMAX system not only reduces operators´ network construction cost, but also helps them roll out a variety of new, competitive and revenue-generating services.

    (2) Zero Installation at the Terminal to Low Network Construction Cost
Zero installation at the terminal considerably reduces the difficulty and workload of system maintenance and upgrade, thus making possible zero maintenance at the client. This operation mode of zero installation will drive large-scaled deployment and applications of the WiMAX system, as it is more easily accepted by mass consumers.

    (3) Rich Wireless Network Monitoring Information to Low Network Operation Cost
    With wireless network resource monitoring, illegal users can be found to ensure network security.

    With wireless network service monitoring, service allocation can be adjusted dynamically to make full use of network resources.

    With wireless network performance monitoring, possible problems of the system can be found in time, therefore, the operating personnel can act in advance and promptly to prevent possible network faults.

3.4 Support of Roaming Network Architecture
    (1) Terminal Authentication Server, Equipment-level Roaming and Future User-level Roaming
    The system in compliance with the IEEE 802.16 specifications enables interoperability among multiple operators. It supports equipment-level roaming, and the future hand-held equipment will support user-level roaming as network equipment is upgraded in the future.

    (2) Two-level Authentication Mechanism
    The system supports the equipment authentication and the service authentication. The operator can deploy a variety of services in a fast and easy manner. The two-level authentication mechanism increases network security by preventing illegal users access and stopping legal users from using
illegal services.

3.5 Smooth Upgrading to IEEE 802.16e
ZTE´s WiMAX product series is based on the modular and standard design concept. Its baseband part, software and RF part all employ standard interfaces, fully considering the upgrade to IEEE 802.16e protocols.

    ZTE´s WiMAX product series employs Software Defined Radio (SDR) technology for the baseband part. Its baseband channel processing unit board adopts significant number of programmable logic components in design, and reserves sufficient hardware resources. It can support IEEE 802.16e services through software upgrade.
 

4 Conclusions
WiMAX technologies provide an excellent platform for development and application of BWA networks, driving the market exploration of BWA/MBWA systems. Keeping abreast of WiMAX technologies, ZTE´s WiMAX products provide access to IP and E1/T1 services. They meet the requirements for fixed, portable and nomadic applications and support seamless upgrade to mobile and roaming applications in compliance with the IEEE 802.16e technology. In addition, they deliver powerful integrated solutions and demonstrate enormous advantages when combined with other communication products of ZTE. With further improvement of standards and further development of market requirements, ZTE´s WiMAX products are bound to occupy an important position in the field of BWA.

Manuscript received: 2005-10-25