Microwave Radio System : 5 Key Advantages & Disadvantages

Introduction : Microwave radio systems are a unique class of wireless communication technology that operate in the microwave frequency range (1 to 100 GHz) and are best known for their point to point, line of sight (LOS) transmission capability. They are used in applications ranging from cellular backhaul and broadcasting to satellite ground links, radar and military communication.

Microwave Radio System can be used to transmit informations such as voice, data or video over long distances. It relies on radio waves instead of using physical cables. Radio waves travel through free space usually along line of sight path between two fixed points.

Microwave Radio System Architecture & interfaces

The microwave radio system mainly consists of two modules viz. transmitter and receiver. Transmitter converts electrical signals into modulated microwave signal. Receiver demodulates signal back into electrical form for processing. The antenna at transmitter radiates microwave signal into space as focused beam where as receiving antenna captures microwave signal at the other end.

As shown in the figure, it also interfaces with other systems such as cellular, satellite, coaxial cable and fiber optic line. Multiplexer module is used to combine voice and data signals at transmitter. Demultiplexer will perform reverse operations at the receiver.

Let us understand various interfaces of Microwave Radio System.

1. Air Interface (Radio Interface) : This is the open space between two antennas through which modulated microwave signals carrying information are transported. This is Line of Sight link operating at microwave frequencies.

2. Baseband/Data Interface : User traffic equipments are interfaced with radio system carrying voice, data or video or any other form of information. Mux/Demux are used to combine and segregate them at transmit and receive end respectively. This interface allows smooth integration of radio system with circuit switched and packet switched networks. Following are types of interfaces commonly used.

• Ethernet/IP (for data networks, 4G/5G backhaul).

• TDM (E1/T1, STM-1, etc.) (legacy telecommunication systems).

• Hybrid (IP + TDM) in transitional networks.

3. Management Interface : Used for monitoring, configuration and fault management of the microwave radio system. SNMP protocol is used for IP-based monitoring. NMS (Network Management System) software with GUI is used for centralized control.

4. Synchronization Interface : Provides precise timing and frequency synchronization required in telecom networks. Technologies such as SyncE (Synchronous Ethernet), PTP (Precision Time Protocol, IEEE 1588v2), Legacy clock interfaces (2 MHz, 2048 kHz signals) are used. It ensures microwave systems work in harmony with cellular networks (2G, 3G, 4G, 5G), transmission systems and timing sensitive applications.

5. Power Supply Interface : There are two options to power radio equipments viz. DC power supply (−48 V DC common in telecom sites) and AC supply with converters. Often integrated with power backup systems (UPS, batteries, solar panels) for uninterrupted operation.

6. Auxiliary Interfaces : It includes alarms for various failures such as dry contacts, door open, power failure etc.Test ports are also provided by manufacturers for field engineers to measure RF/baseband signals.

Advantages of Microwave Radio

Following are some of the benefits of microwave radio.

1. It eliminates need for laying cables.
2. It offers higher bandwidth/data rates.
3. It is faster to install compared to fiber optic cables. Hence it is useful in emergencies or temporary setups.
4. It is cheaper than satellite links for regional communication.
5. It is easy to add new links without much infrastructure changes.
6. It offers stable and predictable communication for point to point links.

Disadvantages of Microwave Radio

Following are some of the drawbacks of microwave radio.

1. It requires clear LOS between antennas.
2. It supports limited range (typically 30-50 Km). For longer distances, repeaters are needed.
3. At higher microwave frequencies, rain, fog and snow can cause signal attenuation.
4. It is vulnerable to interference from other radio systems.
5. Wireless signals can be intercepted; requires encryption for secure communication.

Conclusion: Compared to other wireless systems, microwave radio systems strike a balance between capacity, cost and coverage. While satellite communication provides global reach and cellular systems deliver mobility, microwave systems excel in offering high speed, stable and cost effective point to point wireless connectivity where fiber installation is difficult or impractical. Despite limitations such as line of sight dependency and weather sensitivity, their benefits like scalability, quick deployment and proven reliability continue to make them a preferred solution for bridging communication networks in both urban and remote environments.