More professional WiMAX broadband wireless access features

WiMAX is no stranger to everyone. As a new generation of promising wireless access technology, WiMAX has many advantages, mature technologies, low costs, and wider bandwidth, all of which are luminous advantages. This article will introduce the features of WiMAX broadband wireless access from the perspective of professional principles.

WiMAX broadband wireless access features 1. application features

First, WiMAX, as a broadband wireless access application, has the characteristics of gradual investment and flexible deployment. network operators can gradually increase investment and gradually expand their capacity to meet the needs of user capacity growth, achieve a relatively smooth cost curve. Secondly, network planning is not restricted by terrain and topography, and is flexible in ministries and bureaus. At the same time, areas with low user density can still achieve low-cost coverage, reducing the risk of initial investment. Once again, the network deployment is fast, and the installation and resizing are convenient. complex network planning is not required, and the network structure is flexible, which can play a huge role in temporary and emergency communication. Finally, as a broadband wireless access technology with a cell radius of 50 km and a access rate of 70 Mbit/s, it can be used as a wireless extension of the man wired mode, it can also be used as an alternative to cable. In particular, it is more competitive for areas with low user density or business volume and scattered distribution than cable mode.

WiMAX broadband wireless access features 2. Physical Layer features

The WiMAX operating frequency ranges from 2 to 66 GHz (for the 802.16 standard: 2-11 GHz; For the 802.16a standard: 10-66 GHz ), the channel bandwidth can be flexibly adjusted within the range of 1.5-20 MHz, facilitating the full use of spectrum resources in the allocated channel bandwidth.

WiMAX uses a macro-cell mode with a maximum coverage of 50 km. When the channel bandwidth is 20 MHz, it supports a shared data transmission rate of up to 70 Mbit/s (in this case, the maximum coverage is 3-5 km ). Multi-sector technology can be used to increase system capacity. One sector can support more than 60 enterprise users or hundreds of home users who use E1/T1 at the same time.

WiMAX uses a variety of advanced technologies, such as OFDM, diversity, and adaptive modulation, to achieve NLOS and block line of sight ONLOS transmission, effectively improving the efficiency of wireless transmission in the city.

The physical layer supports TDD/DMTA and FDD/TDMA radio duplex multiplexing modes to meet the requirements of telecom systems in different countries or regions. Supports single-carrier (SC), OFDM (256 points), and OFDMA (2048 points) modulation modes, which can be flexibly selected as needed. The physical layer can dynamically adjust modulation and physical layer parameters (such as modulation parameters, FEC parameters, power levels, and polarization modes) based on the performance changes of transmission channels to ensure better transmission quality.

WiMAX broadband wireless access features 3. MAC layer features

Supports QoS management to meet different service quality requirements. The MAC layer requests connection bandwidth or adjusts bandwidth in polling mode based on service QoS requirements and service parameters to ensure low latency Requirements for real-time services such as voice and video. In addition, for high error rate and packet loss rate in wireless channels, ARQ is defined based on each application stream to ensure automatic re-transmission of MSDU, a business data unit in the MAC layer, ensure the transmission quality of end-to-end packets.

The MAC layer has the sub-layer CS for the ATM service and grouping service, which can be used to conveniently implement network applications characterized by the ATM service or IP service. At the same time, the MAC layer has a security sub-layer that supports MAC layer security mechanisms for security management such as authentication and encryption.

WiMAX broadband wireless access features 4. business capability

WiMAX uses connection-oriented methods to provide users with data, video, and voice (VoIP) services with QoS performance. In the standard, the MAC layer defines a complete QoS mechanism and defines four different services: Non-requested bandwidth allocation service (UGS) real-time round-robin service (rtPS), non-real-time round-robin service (nrtPS), best-effort service (BE ), they can be used to provide users with high-quality video and voice services, normal quality video and voice services, and non-guaranteed services such as Internet. Bandwidth can be dynamically allocated based on actual business needs, with great flexibility. Therefore, WiMAX can provide different service quality QoS for different services.

WiMAX broadband wireless access features 5. Network Structure Features

Supports point-to-point (PMP, PointtoMultipoint) architecture to build a star access network structure centered on WiMAX base stations. The newly promulgated 802.16a also supports the Mesh architecture. In this architecture, many WiMAX nodes are allowed to build a Mesh through wireless interconnection. This means that the structure of the access network can be flexibly expanded, and WiMAX mesh network coverage can be used in areas not covered by the backbone network to achieve elastic expansion of the man.