by Ashutosh Vasudeva – Sr. RF Engineer
What is a Point-to-Point Wireless Link?
A Point-to-Point (PTP) wireless link is typically used to connect two locations that have a Line of Sight (LOS) and require network connectivity. Often there is one location that has network connectivity, and the other location doesn’t, thus the use of a PTP wireless link being used to extend the connectivity.
How does it work?
PTP wireless links use Radio Frequencies (RF) as the medium as opposed to an ethernet/fiber cable to establish a direct link between the two locations. Depending on the radio frequency being used, the LOS between the sites plays an important role, e.g. if you are using 900MHz unlicensed spectrum, you will be able to establish a non-LOS or near-LOS link whereas if you are using 60GHz spectrum, LOS is required. Each location will have a radio and an antenna. Commonly, this is an integrated antenna solution as the radio and antenna will be in the same housing. When the radio and the antenna are in separate housings, it is called a connectorized antenna solution. In the latter scenario, both are connected via RF Cable/Waveguide etc.
In order to transmit the data, it first must be digitized (converted into 0s and 1s) and modulated onto a carrier wave at a specific frequency. The modulated signal is then sent over the air using radio frequencies from the transmitting antenna to the receiving antenna, where it is demodulated so that the original data can be extracted. The data is then processed and forwarded to end-user devices, such as computers, routers, or other network equipment.
There are a multitude of frequency bands that can be used for wireless communications. In the US, some of these frequency bands are unlicensed, some are licensed, and some are reserved for Military use only. Unlicensed frequency bands like 900MHz, 2.4GHz, and 5GHz, are available for public use but are subject to interference from other devices and thus are mostly used for non-critical applications. Licensed frequency bands can be used for more critical or interference-sensitive applications. A licensed band gives the user/license holder exclusive rights to the frequency thus reducing the risk of interference and increasing the reliability of the transmissions.
To help prevent any potential errors from occurring PTP systems are equipped with mechanisms to detect and correct any errors that could occur during transmission either because of interference or sudden changes in environmental conditions. Radio software allows for monitoring of link performance, signal strength, and other key performance indicators. This software can also help diagnose alignment and interference-related issues. Some more advanced systems can automatically adjust settings like frequency, power, and modulation schemes to optimize performance in changing environmental conditions. For example, some unlicensed radios can perform frequency scans in the background and can seamlessly switch frequency/channel if high interference is detected on the operating frequency/channel. Most licensed radios are equipped with powerful features like Adaptive Coding and Modulation (ACM), which allows the radio to gear shift among multiple modulation schemes without dropping the link. Thus, increasing the reliability of the PTP link. Also to ensure the security of the transmitted data the PTP links often use encryption and authentication protocols to protect against unauthorized access or interception.
Reasons to implement a PTP solution?
There are many reasons why an organization or municipality could find the need to implement a PTP solution. Some of those reasons are explained below.
Lack of Physical Infrastructure
In remote or rural areas, laying down cables is often impractical due to the distance and natural obstacles like rivers, mountains, or forests. A wireless PTP link can bypass these obstacles by establishing a direct connection over the air.
High Cost of Wired Solutions
Installing wired connections, especially over long distances or difficult terrains, can be extremely expensive. Whereas a PTP wireless solution can be a much more cost-effective alternative, reducing the need for extensive physical infrastructure.
Time-Consuming Deployment
Wired solutions can take weeks or months to deploy, especially in areas requiring significant construction work. PTP wireless links can be set up relatively quickly, often within days, providing rapid deployment for urgent needs.
Temporary Connectivity Needs
Temporary events such as construction sites or emergency situations often require network connectivity that doesn’t justify permanent infrastructure. A PTP wireless solution can offer a quick and temporary solution that can be easily dismantled or relocated as needed.
Network Expansion in Built-up Areas
Expanding wired networks in densely populated or built-up areas can be challenging due to space constraints and the need to avoid disrupting existing infrastructure. PTP wireless link allows for network expansion without the need for additional cabling, minimizing disruption and avoiding physical limitations.
Reliability Issues with Existing Wireless Networks
Wi-Fi networks, especially in congested areas, can suffer from interference, limited range, and inconsistent performance. A PTP wireless solution can provide a dedicated, stable, high-bandwidth connection, overcoming the limitations of traditional Wi-Fi.
Interbuilding Connectivity
Connecting multiple buildings on a campus or within an industrial complex can be difficult with traditional cabling, especially if there’s a need to cross public roads or other barriers. A PTP wireless solution can create a seamless, reliable high bandwidth connection between buildings, avoiding the need to navigate physical obstacles.
Bandwidth Limitations
Some environments require the transfer of large amounts of data between two points, which can overwhelm traditional wireless solutions. A PTP solution often offers higher bandwidth and can support demanding applications like video surveillance or data-intensive business operations.
Security and Possible Interference from Public Wireless Networks
Public Wi-Fi networks can suffer from interference due to the large number of users and devices. These networks are also widely accessible and can be vulnerable to security threats like hacking. A PTP wireless network operates on dedicated channels and is a direct connection that is typically encrypted. Thus, providing a connection that is more secure and stable.
PTP technology offers a versatile and efficient solution for connecting two locations, especially when traditional wired infrastructure can be impractical and not cost effective. By utilizing radio waves and relying on a clear line of sight, PTP systems provide a secure, high-performance alternative to wired connections. With rapid deployment capabilities, cost savings, and scalability, a PTP wireless solution is ideal for a wide range of applications. A few examples can be connecting remote sites to enabling temporary networks. PTP solutions can overcome geographical obstacles, provide dedicated bandwidth, and enhance network security. These aspects are what make a PTP wireless link an attractive option for organizations seeking reliable, secure, and flexible connectivity solutions.