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White Paper
Best Practices for UBR Installation in
Urban Areas to Mitigate RF Interference

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Optimal Strategies for UBR Installation

The Unlicensed Band Radio (UBR) operates in the 2.5GHz and UBRs are priced significantly lower than traditional
5/6GHz frequency bands, which are license-free in most licensed-band microwave radios, resulting in substantial cost
countries and commonly used in Wi-Fi networks. Currently, savings for telecom operators, encompassing equipment
the 5GHz UBR is employed for providing wireless leased lines costs, operation and maintenance (O&M) expenses, and
with dedicated capacity to enterprise customers in a recurring licensing fees.
point-to-multipoint (P2MP) configuration. Additionally, it is
utilized for backhauling small cell Base Transceiver Stations Due to the increased deployment of UBRs in Telco networks,
(BTS) in point-to-point (P2P) mode within mobile networks. interference issues are on the rise. Careful planning and
installation of UBRs in the field are essential to mitigate
The license-free status of the 5GHz frequency band makes it interference impact and enhance overall network
the preferred choice for telecom operators, particularly for performance. As collated based on field experience, below
small cell BTS backhauling. points should be considered while planning and installing
UBRs in the field so that optimum performance is achieved
and interference impact is reduced.
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Plan the Transmit Power carefully to achieve a Received Signal

Level (RSL) around -46dBm for MCS-9 and -40dBm for
MCS-11 UBR. This ensures a link fade margin of at least 15dB.

Avoid using maximum transmit power to prevent interference

with other links and to maintain network performance.

Link Budget & In urban areas, limit UBR deployment plans to a hop distance
of a maximum of 5 km. Optimal UBR performance, in terms of
throughput and stability, is observed for links with a hop

Planning distance equal to or less than 3 km.

In Rural, the hop distance can be extended to 12 km to 15 km

because the deployment of UBRs are very less compared with
urban. Therefore, the RF environment in rural areas is much
cleaner than in urban areas.

Plan two or more links from the same site only if the azimuth
difference between two adjacent links is more than 60o.
Restrict maximum four links from a single site.
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Antenna
Installation
Install the antenna at the lowest height necessary to maintain
a clear Line of Sight (LOS). Avoid placing the UBR antenna at
the tower's top, as this location is more susceptible to
interference.

Position the UBR antenna at least 2 m away, both horizontally

and vertically, from the BTS/RRU. This separation helps
eliminate the impact of high-power radiation from the RRU on
the UBR. UBRs are equipped with wide-band filters and
amplifiers, which may not sufficiently suppress high-power
RF signals radiated from nearby BTS/RRU installations,
potentially causing interference and impact on UBR
performance.
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UBR Antenna
Scenario 1
Edge Installation

Installation on
Installation on the edge of the building using a 2 ft pole, as
depicted in the diagram below. This type of setup is not
recommended as it exposes the antenna to receive undesired

the Rooftop of a
and interfering signals.

Building
When installing the UBR antenna on the rooftop of a building,
consider the following scenarios to optimize performance by
mitigating interference from surrounding signals.
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Scenario 2 Scenario 3
Near-Edge Roof Installation Backside Roof Installation
Install the antenna on the roof approximately 3 ft away from Install the UBR antenna on the back side of the roof with the
the building's edge, as illustrated in the diagram. The roof area in front of the antenna left exposed. The exposed
building's edge/wall serves as a barrier, blocking interfering roof in front acts as an effective obstruction against interfering
signals and improving performance in highly interfered signals from various directions. Refer to the diagram below for
environments. This is the preferred and recommended this scenario. Maintain a height of approximately 2 m or 7 ft
installation. from the roof to ensure that any human activity on the roof
does not obstruct the Line of Sight (LOS) for the link. This
installation is highly recommended when feasible.
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Antenna Alignment Procedure for Optimal RSL Achievement

Performing antenna alignment is crucial to achieving the Received Signal Level (RSL) specified in the link budget. Acceptable RSL
variation falls within the range of +/- 2dB. If the planned RSL is not attained, it has been observed that the antenna may be locked in
the side lobe. To come out from such a situation, it is advised to do antenna alignment following below steps:

Horizontal a Vertical b Horizontal c Vertical d Iterative e

Alignment (Azimuth) Alignment (Tilt) Realignment Realignment Alignment

Slowly align the antenna Align the antenna from top Repeat the alignment Move the antenna in the Repeat steps (c) and (d)
from left to right and then to bottom and then from process slowly in the vertical direction, both up until the planned RSL is
from right to left. bottom to top, adjusting it horizontal direction, and down, from the last consistently achieved.
slowly. moving left and right from achieved point in step (b).
Tighten the alignment at the previously achieved
the point where the Lock the alignment at the point in step (a). Lock the alignment at the
maximum RSL is achieved. point where the maximum point where the maximum
RSL is reached. Lock the alignment at the RSL is obtained.
maximum RSL point.

Adhering to these alignment steps systematically ensures that the antenna is precisely positioned to meet the desired RSL,
contributing to optimal performance in the link configuration.
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Optimal Channel Dynamic Channel Routine Radio

Selection Selection (DCS) for Health Check
Following antenna alignment, conduct a
spectrum scan and choose the channel
Interference-Prone Sites Perform regular day-to-day health checks
on the radio, monitoring critical Key
with the least interference at the specific For sites with high interference susceptibility, Performance Indicators (KPIs) such as
site. Configure the UBR to operate on the consider enabling the Dynamic Channel Selection Received Signal Level (RSL), throughput,
selected optimal frequency channel. (DCS) feature in the UBR to enhance channel and latency to ensure ongoing
adaptability and mitigate interference. operational integrity.

Summary
The strategic deployment of Unlicensed Band Radios (UBRs) in urban areas offers a compelling solution for wireless communication, balancing
cost-efficiency and operational excellence. The detailed considerations provided, encompassing frequency planning, antenna installation, alignment
procedures, and interference mitigation, establish a robust framework for telecom operators aiming to enhance UBR performance while navigating the
challenges of urban environments. By diligently implementing these practices, operators can optimize wireless networks, ensuring resilience against RF
interference and fostering a reliable communication infrastructure for the evolving demands of urban connectivity.

Author: Rakesh Kumar (Senior Vice President)

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Not all offerings are available in every country in which HFCL operates. The data used in this report may be derived from third-party sources and HFCL does
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guidance only. It is not intended to be a substitute for detailed research or the exercise of professional judgment. HFCL shall not be responsible for any loss
whatsoever sustained by any organization or person who relies on this publication.

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