WLL

 Wireless Local Loop (WLL) is a system that connects subscribers to the public switched telephone network (PSTN) using wireless technology for the "last mile." Traditionally, this last mile has been predominantly wired, typically using copper telephone wires. WLL is particularly valuable in areas where laying wires is impractical due to geographical challenges, or economically unfeasible due to low population density.

How Wireless Local Loop Works

Wireless Local Loop systems involve several key components:

1. Base Station: This acts as the central hub in the WLL system. It is connected to the PSTN and communicates wirelessly with the subscriber units. The base station manages signal transmission and reception over the network.

2. Subscriber Units: These are devices located at the subscriber's premises (homes or businesses) that communicate with the base station. These units can be fixed, portable, or mobile, depending on the technology and service provider.

3. Backhaul Connection: Connects the base station to the main telephone network (PSTN). This can be a wired connection (like fiber optic cables) or another form of wireless communication.

Types of Wireless Local Loop

Wireless Local Loop can be categorized based on the type of wireless technology used:

1. Radio WLL: Uses radio frequencies for wireless communication. This type can be further divided into two sub-types:

   • Fixed Radio Access (FRA): The subscriber has a fixed location.
   • Mobile Radio Access (MRA): The subscriber can move within the coverage area.

2. Microwave WLL: Uses microwave frequencies to establish a point-to-point link between the base station and subscriber unit.

3. Infrared WLL: Uses infrared signals for data transmission, which requires line-of-sight and is less common due to its range and environmental limitations.

Technologies Used in WLL

A variety of technologies have been deployed for WLL systems, including:

• DECT (Digital Enhanced Cordless Telecommunications): Originally designed for cordless phone systems in residential and corporate environments, DECT can also be used for WLL to provide a range of up to several hundred meters.

• CDMA (Code Division Multiple Access): Provides high capacity and security, making it suitable for both voice and data communications in WLL setups.

• GSM (Global System for Mobile Communications): While primarily known for mobile communications, GSM can also be adapted for fixed WLL setups.

Advantages of Wireless Local Loop

• Cost-effective: Eliminates the need for extensive underground cabling, which can be particularly expensive in difficult terrains or less densely populated areas.
• Rapid Deployment: Can be deployed much faster than traditional wired connections, allowing for quick service rollout.
• Flexibility: Can provide service in areas that are otherwise hard to reach with traditional wiring, including rural or newly developed areas.

Challenges Facing WLL

• Quality of Service: WLL systems can sometimes offer lower data rates and reliability compared to wired connections. Environmental factors like weather can also impact the quality of service.
• Interference: Wireless systems can suffer from interference from other wireless devices or networks operating in the same or nearby frequency bands.
• Regulatory and Spectrum Allocation: Effective deployment of WLL systems requires access to appropriate radio frequencies, which may involve regulatory challenges and costs related to spectrum licensing