brief introduction

The commercial square includes shopping malls, office buildings, hotels, apartments, luxury homes, as well as supporting facilities such as parking lots. The wireless cluster communication system is divided into three management modes (groups): large property, shopping malls, and hotels. Each format of communication requires relative independence. Each format has two to five departments, and their communication will not interfere with each other.



programme

The commercial square includes shopping malls, office buildings, hotels, apartments, luxury homes, as well as supporting facilities such as parking lots. The wireless cluster communication system is divided into three management modes (groups): large property, shopping malls, and hotels. Each format of communication requires relative independence. Each format has two to five departments, and their communication will not interfere with each other. In this case, large properties can schedule all intercom functions, including hotels and shopping malls.



The communication effect covers the communication needs of the entire ground floor, basement, vertical elevator cars, and nearby outdoor areas, achieving full coverage of wireless communication networks. In the above area, you can use walkie talkies to communicate with each other. Based on the actual situation and current usage of wireless frequency, the 400MHz frequency band can be selected as the wireless communication frequency for buildings. Due to the use of wireless clustering in the communication system of this walkie talkie to solve the problem of dividing the communication channel, it is necessary to apply for two sets of radio frequencies and use a combination branch method, while maintaining the wiring structure of the system unchanged.



The design of this system enables signals to effectively cover public areas of buildings and areas with frequent human activities, enabling the entire system to achieve unified coverage, with clear, stable, and reliable signals. This plan needs to ensure that the above requirements meet the requirements of internal management, property use and maintenance, as well as safety, fire protection, emergency communication, etc. of the building, in order to facilitate internal management, maintenance, safety, and firefighters can easily and quickly maintain contact and communication.



Design principles



① On the premise of ensuring system quality, try to use low-cost methods to design solutions;



② Reasonably set the position, quantity, and output power of antennas to ensure the use of fewer antennas and lower output power to achieve good coverage;



③ Due to frequent high-rise switching and high drop rate, the design should strive to achieve uniform indoor field strength and good signal strength;



④ Try not to use a trunk amplifier to reduce the introduction of noise;



⑤ Establish a comprehensive wireless coverage network;



⑥ Considering the relatively easy implementation and efficiency of construction, especially the reasonable layout of wiring;



⑦ The link meets a carrier noise ratio greater than 15dB in the coverage area.



operational principle



The system adopts IP networking to form a single base station cluster communication system with multiple digital relay stations. Supports up to 8 voice relay channels and 16 data channels. The maximum user capacity can reach 800. There is no need for the control channel of traditional cluster systems, and all 8 time slots can be used, without wasting system time slots and requiring application and licensing mechanisms. When a new call starts, the idle time slot will be transferred to the new idle time slot. The system notifies all idle walkie talkies to transfer to the idle time slot, converts the original idle time slot into a call time slot, and relays voice communication on that time slot. When the call is terminated, the call time slot will notify the radio of a new idle time slot or related time slot.



System structure



Based on the structure of the building, the actual situation of the surrounding electromagnetic environment has been considered. Due to the wide coverage of the communication network, including the South Tower and North Tower, with two underground floors and mezzanine layers, reinforcement technology has been adopted



Concrete structure has a significant shielding (attenuation) effect on radio frequency signals. Low coverage of wireless intercom communication. Ensure that there are no communication blind spots (spots) and that the wireless intercom system communicates normally.



The system design ensures that the signal is within the corresponding spatial area, that is, the effective coverage area of the intercom signal is the aboveground building. The intercom signal effectively covers the building equipment room, fire elevator, safety passage, and the entire outdoor building, ensuring clear and smooth communication of the wireless intercom system, and achieving unified coverage of the entire system, with clear, stable, and reliable signals.



It is recommended to install a cluster communication base station (fully automatic, unmanned) in the weak current machine room on the underground floor, and distribute the communication antennas in the following positions: design a channel system, multiple suction cup antennas, and non suction cup antennas. The outdoor antenna covers the entire office building, fully ensuring the reliability of the intercom system and wireless intercom communication between property management personnel and security personnel.



Indoor signal distribution



To meet the design requirements and take into account the difficulty of specific construction, the most reasonable route is selected for relay wiring and layout, achieving uniform indoor power distribution. The coverage signal in this scheme is transmitted to each floor through feeder lines by indoor active power distribution devices. Strictly calculated according to the equipment and feeder technical indicators, the indoor coverage antenna power is controlled below 15dBm, which meets the national electromagnetic environmental hygiene standards.



The omnidirectional suction cup antenna for sending and receiving signals is placed at the top of the ceiling and connected to the relay station on the first floor of the computer room through a feeder line. The wireless signal distribution system receives and sends signals from antennas, which are connected to shielded cables. The wireless intercom signal indoor distribution system solves the signal coverage of the entire public network and dedicated signals within the building.