Introduction to five typical wireless access systems

If you hear about the wireless access system, you will find it relatively high-end and difficult to understand. In fact, the fixed terminal devices and mobile devices we are currently using belong to the category of the wireless access system. this section describes typical wireless access systems ｡

Wireless Access refers to the use of wireless means in part or whole from the exchange node to the user terminal ｡

A typical wireless access system consists of controllers, Operation and Maintenance centers, base stations, fixed user units, and mobile terminals ｡

Typical Wireless Access System 1. Controller

The Controller is connected to these functional entities through interfaces provided by the Controller with switches, base stations, and operation and maintenance centers. The main function of the controller is to process user calls (including call establishment and disconnection) management of base stations, wireless channel control through base stations, monitoring of base stations, and monitoring and management of fixed user units and mobile terminals ｡

Typical Wireless Access System 2. Operation and Maintenance Center

The operation and maintenance center is responsible for the operation and maintenance of the entire wireless access system. Its main function is to manage the configuration of the entire system and operate the software and various configuration data of each network unit: all parts of the system are monitored and collected during system operation. faults in the system operation are recorded and alarms are triggered. In addition, the system performance can be tested ｡

Typical Wireless Access System 3. Base Station

The base station provides a wireless channel between a fixed terminal device and a mobile terminal through a wireless transceiver, the Controller manages wireless channels through the base station. Different technologies can be used for wireless interfaces between the base station and fixed terminal devices and mobile terminals, it also determines the characteristics of the entire system, including the wireless frequency used and its applicability ｡

Typical Wireless Access System 4. fixed terminal Devices

The fixed end-to-end device provides users with the Z interface, a standard interface for user terminals such as telephone, fax, and data MODEM. It is connected to the base station through wireless interfaces and transparently transmitted to end users. provides services and functions. Fixed End-to-end devices can use oriented antennas or non-Directional antennas, direct targeting of a targeted antenna to a base station can improve the transmission quality of the signal in the wireless interface, and increase the coverage of the base station; fixed End-to-end devices can be divided into single-user units and multi-user units. A single-user unit (SSU) can only connect to one user terminal. It is applicable to scenarios with Low user density and long distance between users; multi-user units can support multiple user terminals. Generally, there are multiple user units that support four, eight, 16, and 32 users, multi-user units (such as a user upstairs) are relatively cost-effective when the distance between users is very close ｡

Typical Wireless Access System 5. Mobile Terminals

A mobile terminal can be regarded as a physical entity that combines a fixed terminal device with a user terminal. Because of its mobility, therefore, in addition to the functions of the Fixed Wireless Access System, it also has certain features such as mobility management for cellular mobile communication systems. If there is a breakthrough in the price, the mobile terminal will be more popular with users and operators ｡

Generally, wireless access can be divided into two types in terms of structure. One is that local devices are connected wirelessly, it is equivalent to a repeater. Another method is to connect a user terminal to a local device through wireless access ｡