A Primer About Distributed Antenna System (DAS)

Cell Phone Signal Repeater
Cell Phone Signal Repeater
Cell Phone Service Booster
Cell Phone Service Booster

Nowadays we depend on cellular devices like smartphones for accomplishing various daily tasks. These are possible with the help of applications that requires good cellular network connectivity. This is also true for businesses as well. So, having bad cellular signal reception can be quite frustrating due to issues like dropped calls, poor data services, bad calls, and video quality, etc. The best way to ensure good network connectivity is to use a distributed antenna systems (DAS), and one such widely used device is a cellular signal booster; read on to know more about DAS.

What Is A Distributed Antenna System (DAS)?

The DAS is a network of antennas distributed throughout an area or a building to improve cellular network connectivity. It is connected to a common source signal, which is broadcasted through the antenna network of the DAS. The antennas are distributed in such a way that their coverage area does not overlap with each other. This ensures seamless connectivity inside the building where DAS is installed. Besides, it is power efficient compared to a large antenna used for covering a wider area.

A DAS can be customized for indoor or outdoor use, and it is widely used inside large spaces like shopping malls, airports, hospitals, roadway tunnels, subways, etc. Due to this, there is also the added benefit of improving public safety, and this is especially useful during emergencies as it ensures that people can call emergency services.

Different Type Of Distributed Antenna Systems (DASs)

There are two basic components for a DAS, the signal source and the signal distribution system. The input of the DAS is the signal source, and it can be on the site like a Base Transceiver System (BTS), an antenna on the rooftop, or a small cell. The received signal is distributed through the distribution system of antennas. The four types of DAS are active, passive, hybrid, and digital; they are explained in detail below.

Active DAS

In an active DAS, an analog RF signal from the signal source is transmitted to the master unit to be converted into a digital signal. The digital signal is transmitted to the network of distributed antenna system through a fiber optic or Ethernet cable. There, the digital signal is reconverted to analog RF and broadcasted throughout the building where the DAS is installed.

An Active DAS requires a carrier-grade high capacity infrastructure, and due to this, it provides high-quality cellular network connectivity. Its installation process is complex and invasive to the structure of a building due to fiber optic cabling. Because of this, its implementation is a costly and time-consuming process. Due to these reasons, active DAS systems are not widely used.

Passive DAS

Passive DAS is also known as a cell phone service booster and is one of the most popular solutions to improve cellular network connectivity inside buildings. Its main components are the outside antenna, the amplifier, and the inside antenna. These three components are connected using coaxial or coax cables. The outside antenna is also known as the donor antenna, and it receives weak cellular signals. They are transmitted to the amplifier for boosting, and the boosted signals are retransmitted to the inside antenna for broadcasting. A signal booster can enhance weak cellular signals by up to 32 times, and this depends on the gain of the amplifier.

The performance of a passive DAS depends on multiple factors. It depends on the type of the outside antenna used, i.e. an omnidirectional antenna or a directional antenna. It is also affected by the gain of the amplifier, and this is determined according to the strength of the outside antenna. Besides, the type and length of coaxial cables used also determines the performance of the cell phone service booster. As the length of the cable increases, more will be the loss in signal strength.

Hybrid DAS

In hybrid DAS, the analog RF signal from the signal source is transmitted to the master unit that converts it to a digital signal. It is then transmitted via fiber optic or Ethernet cables to Remote Radio Unit (RRU) installed on each floor of a building. The digital signal is converted back into RF signal by the RRU and is transmitted to the network of distributed antennas through coaxial cables. Hence, a hybrid DAS uses a combination of coaxial and fiber optic cables for signal distribution inside a building.

Digital DAS

In digital DAS the baseband unit, i.e. signal source communicates directly with the master unit of the DAS system without any conversion to analog RF interface. The communication with remote units is also similar.

The Advantages And Disadvantages Of DAS

The most important advantage of the DAS is that it improves the coverage area, and as a result, there are fewer dead zones or bad network coverage areas. Its power consumption is lower than the larger antenna used for covering wider areas. Its main disadvantage is the higher cost due to additional hardware installation.

We hope this guide clarified your doubts about Distributed Antenna Systems (DAS) and will be of use to you in selecting one.