Repeaters and Bi-Directional Amplifiers (BDAs) BDAs boost the cellular signal by rebroadcasting it inside the building from an existing local cell site. They are coverage-only solutions. Operators must approve BDA deployments as they can interfere with the macrocellular network. Depending on the services in the area, multiple BDAs might be needed to properly cover the area. Small Cells Small cells are an umbrella term given to microcells, metrocells, picocells, and enterprise radio access networks (E-RAN). These are operator-controlled, low- powered radio access nodes, including those that operate in licensed spectrum and unlicensed carrier- grade Wi-Fi spectrum. Traditional small cells are typically low-power radio access points designed to increase coverage and capacity within a short range and can handle a limited number of users; they generally have a range from ≈10 m (32 ft) to several hundred meters. An E-RAN can scale to cover very large venues and thousands of data sessions. Small cells are generally indoor, premise- based deployments that go beyond a home office environment. They are primarily coverage-driven, with a need for high reliability, although they can be deployed to support capacity requirements as well. DESIGN PHASE CONSIDERATIONS Mobile broadband connectivity is not always considered during initial architectural drawings, or early in the design process for new buildings. In fact, some building design aspects, like low- emission glass and building material choices like aluminum, can hinder RF transmissions and necessitate additional in-building connectivity to be brought into the venue. That challenge is compounded by higher frequencies now being used in cellular networks that are inherently less able to penetrate buildings. More established buildings also can suffer from poor in-building connectivity. This can result in buildings being less desirable when trying to attract new tenants or improve employee productivity. Much of the cost of deploying in-building connectivity can be defrayed by including plans for licensed and lightly licensed
connectivity into the process early in the design stage for new buildings or during planned renovations to an existing building. It is easier to run the necessary optical fiber, antennas, and other equipment when ceilings, floors, and walls are exposed. In existing buildings, adding wireless infrastructure should be considered during remodeling periods or as a stand- alone service. In both cases, new buildings or existing ones, those who plan and account for the venue’s connectivity needs can achieve the desired outcomes and make the process less costly. Many factors can influence how in-building networks are designed and optimized, including the availability of optical fiber, cabling pathways, physical space to house equipment, building aesthetics, carrier approvals, power requirements, ongoing maintenance needs, the size of the building, and traffic patterns within the structure. While each venue is unique, they generally have common design, approval, and construction issues. Up front preparation, thoughtful design, and continued project support can save sig- nificant installation time, improve design efficiency, and reduce costs even in the most difficult project environments.
To ensure seamless connectivity throughout a building, the following items should be part of the initial design process and followed during con- struction of the system: • Depending on the size of the building(s)/venue and the number of wireless carriers connecting to the DAS, having a common equipment space for the head-end equipment is critical. Locating equipment in existing IT rooms and closets can be an option. However, the building IT department will need to review and understand future space and resource requirements for both the building IT and DAS equipment. Often these spaces end up on mechanical, basement, or parking levels, which can pose environmental issues. The design in these areas should be reviewed carefully to mitigate potential issues like moisture and dust. • HVAC is critical for DAS equipment spaces. Existing cooling capacity should be assessed for both the initial and anticipated future growth of the system. Dedicated IT cooling is required year-round so standard building cooling or small residential-type applications should be reviewed carefully. HVAC systems that are designed specifically for IT applications and that are scalable are strongly recommended. Ductwork and raised floor applications required for proper air circulation should be coordinated with the cabling design to minimize pathway conflicts. • Power for the DAS head-end is an important consideration. The capacity of the existing power distribution system should be analyzed. Neutral- host DAS power designs should include considerations for the additional requirements of future carriers. If the building is supplying the power, metering and interconnection for smart- building monitoring will need to be coordinated with building management. Utility metering will require coordination with the local power utility and can be a long lead item that can delay system activation. Utilizing building back-up power or installing a back-up generator to harden the system are additional design considerations.
• Fire protection for the head-end and maintenance of existing fire wall assemblies is another important design consideration. For spaces with existing sprinkler systems, new walls or rooms within the space may require modifications or additional sprinkler heads. For critical system infrastructure or larger DAS systems, a pre-action sprinkler system may be a consideration to reduce the chance of accidental discharge. Clean agent gas systems like the FM-200 fire suppressant agent can also be used to minimize damage to the electrical equipment should fire suppression be required. Early warning notification air sampling systems can also minimize notification and response time to a smoke or fire situation. Fire stopping of cabling and utility penetrations throughout the building is also an important consideration. All wall and floor penetrations should be sealed to maintain the existing wall rating. This is especially critical in hospital environments, where wall fire ratings are critical to the venue’s evacuation plan. For penetrations where future cabling is anticipated, penetration products are available that are resealable and accelerate future cabling installations. It should be noted that cabling should never be routed through egress hallways or stairwells unless it is related to the function of that egress as allowed by the building code. Cabling that passes through plenum spaces is required to be plenum-rated to meet low-smoke, low-flame spread requirements. • The design requirements for accessory equipment cabinets should not be overlooked. Depending on the system manufacturer and configuration, remote cabinets that are required for conversion from optical fiber to coaxial cabling will need to be located throughout the building. Locations for these remotes are often in IT or mechanical rooms, where space may be limited, so performing initial inspections of potential remote locations should be performed during the design phase. Considerations for power and back-up batteries should also be reviewed and included as part of the design phase.
FIGURE 2 : Wireless infrastructure supporting high volume of attendees at the Super Bowl. Source: WIA
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ICT TODAY
April/May/June 2025
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