Worldwide Interoperability for Microwave Access (WiMAX) technology has rapidly developed in recent years. It is becoming one of the hotspots among broadband wireless access technologies. A WiMAX system can provide ban...Worldwide Interoperability for Microwave Access (WiMAX) technology has rapidly developed in recent years. It is becoming one of the hotspots among broadband wireless access technologies. A WiMAX system can provide bandwidth efficiency higher than 2 bps/Hz. In order to improve coverage and reliability of the WiMAX system,the IEEE 802.16 standard supports multiple antenna techniques such as Alamouti Space-Time Coding (STC),Adaptive Antenna System (AAS) and Multiple Input Multiple Output (MIMO). The applications of the multiple antenna techniques improve system capacity and bandwidth efficiency significantly,and enhance the competence of the WiMAX technology greatly.展开更多
Based on the introduction of the WiMAX standards, relevant technologies and applications, three essential factors for WiMAX networking are analyzed. They are the frequency plan, Authentication Authorization Accounting...Based on the introduction of the WiMAX standards, relevant technologies and applications, three essential factors for WiMAX networking are analyzed. They are the frequency plan, Authentication Authorization Accounting (AAA) and the mobility management. Networking solutions for the fixed and mobile applications are presented respectively. It is noted that the evolution of wireless WiMAX networking will go through four phases: the outdoor access phase, the indoor access phase, the seamed roaming phase and the seamless mobility phase. It is predicted that WiMAX will eventually converge with the NGN and the mobile cellular networks.展开更多
Despite the rapid development in Worldwide Interoperability for Microwave Access (WiMAX) technologies,key technologies for the Physical Layer (PHY) still need to be further improved so as to achieve highly efficient a...Despite the rapid development in Worldwide Interoperability for Microwave Access (WiMAX) technologies,key technologies for the Physical Layer (PHY) still need to be further improved so as to achieve highly efficient and reliable communication performance,as well as to support a mobile environment with a higher transmisison rate. As an amendment to IEEE 802.16d (for fixed broadband wireless access systems),IEEE 802.16e (for mobile broadband wireless access systems) introduces the Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) technologies into the PHY,doubling the transmission rate while supporting a certain degree of mobility. In the future,more advanced Air Interface (AI) technology is to be applied in the IEEE 802.16m standard.展开更多
It is a difficult problem to improve network performance and resource utilization efficiency in wireless communications. As a standard of broadband wireless access systems, IEEE 802.16 adopts Orthogonal Frequency Divi...It is a difficult problem to improve network performance and resource utilization efficiency in wireless communications. As a standard of broadband wireless access systems, IEEE 802.16 adopts Orthogonal Frequency Division Multiplexing (OFDM) and multi-modulation/coding techniques at the physical layer, combines contend and pre-contract mechanisms at the Medium Access Control (MAC) layer. Based on the QoS-related concepts such as connection and service flow, IEEE 802.16 optimizes network entry and initialization, and frame format in order to improve network throughput, reduce network delay, and increase the flexibility of network configuration. Based on IEEE 802.16, WiMAX adopts Point-to-Multipoint (PMP) network topology to realize flexible networking. It is a typical application technology of broadband wireless access systems.展开更多
文摘Worldwide Interoperability for Microwave Access (WiMAX) technology has rapidly developed in recent years. It is becoming one of the hotspots among broadband wireless access technologies. A WiMAX system can provide bandwidth efficiency higher than 2 bps/Hz. In order to improve coverage and reliability of the WiMAX system,the IEEE 802.16 standard supports multiple antenna techniques such as Alamouti Space-Time Coding (STC),Adaptive Antenna System (AAS) and Multiple Input Multiple Output (MIMO). The applications of the multiple antenna techniques improve system capacity and bandwidth efficiency significantly,and enhance the competence of the WiMAX technology greatly.
文摘Based on the introduction of the WiMAX standards, relevant technologies and applications, three essential factors for WiMAX networking are analyzed. They are the frequency plan, Authentication Authorization Accounting (AAA) and the mobility management. Networking solutions for the fixed and mobile applications are presented respectively. It is noted that the evolution of wireless WiMAX networking will go through four phases: the outdoor access phase, the indoor access phase, the seamed roaming phase and the seamless mobility phase. It is predicted that WiMAX will eventually converge with the NGN and the mobile cellular networks.
文摘Despite the rapid development in Worldwide Interoperability for Microwave Access (WiMAX) technologies,key technologies for the Physical Layer (PHY) still need to be further improved so as to achieve highly efficient and reliable communication performance,as well as to support a mobile environment with a higher transmisison rate. As an amendment to IEEE 802.16d (for fixed broadband wireless access systems),IEEE 802.16e (for mobile broadband wireless access systems) introduces the Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) technologies into the PHY,doubling the transmission rate while supporting a certain degree of mobility. In the future,more advanced Air Interface (AI) technology is to be applied in the IEEE 802.16m standard.
文摘It is a difficult problem to improve network performance and resource utilization efficiency in wireless communications. As a standard of broadband wireless access systems, IEEE 802.16 adopts Orthogonal Frequency Division Multiplexing (OFDM) and multi-modulation/coding techniques at the physical layer, combines contend and pre-contract mechanisms at the Medium Access Control (MAC) layer. Based on the QoS-related concepts such as connection and service flow, IEEE 802.16 optimizes network entry and initialization, and frame format in order to improve network throughput, reduce network delay, and increase the flexibility of network configuration. Based on IEEE 802.16, WiMAX adopts Point-to-Multipoint (PMP) network topology to realize flexible networking. It is a typical application technology of broadband wireless access systems.
