Infrastructure guidance

Planning for the provision of wireless connectivity should start at the outset of the construction process. This ensures that clinical and business networking requirements are met, that the costs of implementing wireless connectivity solutions are minimised, and that there is the flexibility and capacity required to meet future networking requirements.

For example, it is important to identify at the very beginning, whether the requirement is to allow external commercial network coverage to penetrate the building, or whether this ‘outdoor-in’ coverage should be prevented for the benefit of private indoor networks. This will be driven by the technology use cases that will take place at each particular health and care setting.

As an example of a design and build process, the Royal Institute of British Architects (RIBA) Plan of Work is an industry-standard methodology that details each step of the process in a building, construction or design project.

The Plan of Work lists all the tasks and outputs required at key stages of the project. Though other methodologies are available, the RIBA Plan of Work is the one most commonly used in UK construction and has become the de facto model for the construction process. Regardless of the construction methodology used, the principles described in this report apply.

The RIBA Plan of Work provides a framework against which the planning, design and implementation of wireless networks can be aligned.

However, the RIBA Plan of Work does not currently identify a requirement to engage with radio frequency engineering professionals.

A common error in the construction of new health and care buildings is that radio frequency engineering professionals are not involved in a new build or major refurbishment project until after the works have been completed.

This results in additional construction costs, additional effort from technicians and installers, lengthier and more complex implementations, delays in service provision, delays to the overall construction project, and potentially reduced performance.

The 8 stages of the RIBA Plan of Work are summarised below:

0: Strategic definition: During Stage 0, the project must be strategically appraised and defined, so that a detailed brief can be drafted. This ensures that the client’s business case has been properly considered and addressed.

1: Preparation and briefing: Stage 1 involves developing the project brief and conducting any necessary feasibility studies. Factors like site information, spatial requirements, budget restrictions, risk analysis and project outcomes must all be considered.

2: Concept design: The initial concept design for the building will now be produced in line with the project brief. At Stage 2, the team will also develop several key project strategies, like security and sustainability.

3: Spatial coordination: The concept design will be further developed, and the architectural, building services and structural engineering designs are coordinated and checked by the lead designer.

4: Technical design: Refining the architectural, building services and structural engineering designs in greater detail. Technical designs will be developed. Designs by any specialist subcontractors will be completed.

5: Manufacturing and construction: This stage is when the actual process of building starts. This includes manufacturing building systems and erecting any components of the building that have been made off-site.

6: Handover and close out: This phase focuses on the successful handover of the completed building, in line with the project programme and includes completing initial aftercare tasks.

7: In use: This involves a post-occupancy evaluation of the building to determine the project’s performance. It is also when facilities and asset management is implemented.

The following diagram summarises at what stage of the RIBA Plan of Work the various stages of the planning, design, implementation and maintenance of wireless networks should be addressed.

The Radio Frequency Engineering Methodology (RFEM) described in this report is not a ‘one size fits all’ approach. The methodology is to be applied in a manner appropriate to the circumstances of the individual project concerned. It is likely that the RFEM would be applied in full for the construction of a new hospital, but not for the construction of a small GP surgery.

In all cases, the services of an appropriately skilled and experienced RF expert should be utilised to provide advice and guidance. In this section of the report, we refer to this person(s) as the RF expert. The RF expert will determine which aspects of the RFEM should be applied to the individual circumstances of the project.

The same approach should be applied, in an appropriate manner, for both new builds and major refurbishment projects.

Figure 3: Alignment of the RIBA Plan of Work and RF engineering methodology

It is, of course, possible to install wireless networks in buildings regardless of whether or not radio frequency engineers have been consulted during the design and build/refurbishment process. However, this always results in delays to the completion of the project and in additional avoidable costs.

By following the guidance contained in this document and engaging an RF expert at the earliest possible stage; the cost and complexity of installing the wireless networks required will be significantly reduced.

During RIBA Stages 0 and 1, the RF expert will review the client’s business case, assess the business requirements and determine whether ‘outside-in’ commercial coverage is required and/or a private Wi-Fi or 5G network, undertake a feasibility study, and produce a budgetary estimate of costs.

Site surveys are appropriate for new builds and for major refurbishments. During the site survey, the RF expert may undertake the following activities:

• carry out field measurements to estimate the existing macro coverage inside the building (such as outdoor macro signal leakage inside the building)
• determine whether a dedicated indoor wireless solution is needed or not based on the macro signal data collected during the evaluation survey
• propose a range of options for wireless solutions, alongside budgetary cost estimates, based on the building size
• assure that the proposed wireless solutions are ‘future-proof’ – capable of being upgraded and of supporting technology roadmaps that reach at least 10 years into the future

During RIBA Stages 2 and 3, the RF expert will create an initial high level RF design. This is a desktop assessment produced using a planning tool (computer software) and is based on the architect’s initial concept designs.

The RF expert’s high-level design will estimate the RF coverage inside the building based on the proposed layout, antenna locations and the effect of the internal walls on the radio propagation. The RF expert will recommend which building materials to use based on the impact of those materials on radio propagation. The RF expert can assist the architects by modelling the impact of the clutter profiles of different materials being considered for ceilings, corridor walls, doors, windows, outer walls, separations and wall partitions. These recommendations can then be taken into consideration by the architects. It is recognised that the requirements of the RF expert will need to be balanced with the needs of other stakeholders and that compromises will need to be made. The following points will be provided by the RF expert at this stage:

• propose potential routing for cables and ducts including use of vertical risers
• plan the location of antennas and access points
• define the installation challenges and recommendation to overcome them
• provide a robust estimate of the costs for installing the wireless connectivity solutions in the building

The product vendors for the wireless solution product will be selected at this stage to allow the RF experts to finalise the network design and deployment plan which will be used during the construction of the building.

At this stage, a document showing the proposed antenna placement, the cable routing, and the coverage predictions based on proposed wall materials is essential. It must be available in advance of RIBA Stages 4 and 5 which relate to finalising the technical designs for the building and starting the construction work.

It is assumed that ICT requirements are covered by the RIBA Plan of Work and are addressed in the mechanical and engineering specifications.

Towards the final phases of RIBA Stages 4 and 5, and once the bulk of the construction is completed, the RF expert will carry out detailed site inspections, collect key information and compile quality reports. This information will be used to fine tune the plan, design and install the wireless connectivity solutions in the recently constructed or refurbished building.

During site surveys, the RF expert may undertake the following tasks:

• Inspect and assure that the telecom equipment room is constructed appropriately based on the high level design
• inspect and assure the distribution rooms for fibre and ethernet cables
• inspect and assure the location of heating and cooling systems, and power equipment
• perform continuous wave (CW) testing to estimate the clutter profile (including the transmission, diffraction, and reflection wall losses) of ceilings, corridor walls, doors, windows, outer walls, separations and wall partitions

The RF expert will produce a detailed RF design. This document contains all the information required to plan, design and install the wireless connectivity solutions required. The detailed design will contain:

• antenna layouts
• design schematics (showing the vertical RF power distribution)
• coverage predictions
• RF and optical link budget
• sectorisation plan
• telecom node configuration (building distribution room design)
• fibre and ethernet cabling diagrams

Once the network design is finalised, the hospital construction company will be able to install the required infrastructure including cabinets and cable trays, the construction company will also be able to lay out the RF cables required.

The hospital construction company will then be joined by a team of RF network experts in order to deploy the proposed RF network solution during the construction of the building. The team will deploy, commission and configure the solution. The team will install switches, access points, antennas, controllers. 

The team of RF network experts will be one of the last trades on site, to enable the solution to be adjusted to account for last minute changes in the layout and construction of the building.

During RIBA Stages 6 and 7, the RF networks installed will be commissioned, integrated, tested, optimised and, following final acceptance testing, they will go live.

Network acceptance testing addresses all aspects of the solution. Specialist industry approved tools will be used to validate all aspects of network performance. This will include: fibre testing, switch configuration, core set up, RF coverage surveys and optimisation.

The Key Performance Indicators (KPIs) used during acceptance testing include:

• throughput tests
• backhaul speed tests
• latency tests
• resiliency tests
• handover tests
• user connectivity at distance
• RF surveys which include: received signal strength, noise level, signal/noise ratio

These KPIs will be used when troubleshooting and optimising network performance after installation. During the acceptance testing process, the RF engineers will collaborate with network design experts to fine tune and optimise the network, to provide optimum performance.

The team of RF network experts will include a design authority responsible for decision making. During acceptance testing, the network design authority may request final adjustments to the physical deployment of the network. For example, adding or removing antennas during network optimisation. Such changes are expected to be minimal, as the initial designs are usually accurate to around 80%.

Once acceptance testing has been completed satisfactorily, the network will be handed over to the network operation team, following a formal transition process.

Installation cost is a key consideration for any RF wireless solution.

To manage these costs, it is essential that the provision and location of a telecom/equipment room, cable distribution rooms, cable trays, antennas and access points are considered at the earliest opportunity.

The earlier in the RIBA Plan of Work process, the better.

Addressing these factors retrospectively will result in avoidable construction costs, additional effort from technicians and installers, lengthier and more complex implementations, delays in service provision, postponements to the overall construction project, and potentially reduced performance.

This principle applies equally to GP surgeries, care homes, community health centres and major hospitals. It applies to new builds and to major refurbishments.

The following case study, provided with the kind permission of Norfolk and Suffolk NHS Foundation Trust (NSFT), illustrates the importance of engaging an RF expert at the earliest stage of the RIBA construction process.

This case study describes the challenges faced by the RF network design and implementation team during the deployment of an enterprise Wi-Fi network across approximately 50 sites located across Norfolk and Suffolk region each containing multiple buildings.

This case study refers to the problems encountered in legacy buildings that were constructed decades ago and prior to the advent of modern mobile telecommunications.
However, it illustrates the potential problems and additional costs that could be incurred if the design, layout and construction of a new building or a major refurbishment does not adequately consider the needs for wireless networks at the earliest possible stage.

Munro’s ‘Shadow Diagram’ illustrates this point. This describes how investment in the design of a building can represent only 5% of a project’s total budget. However, poor design can cause 70% of the waste encountered in later stages of construction and during the lifecycle of the building.

Munro’s diagram is concerned with lean construction. For a non-lean purpose 60% of the total cost of the design, installation and operation of a network are determined by the initial design, and yet only 5% of a wireless network project budget is spent on that stage of the project.

If there is a requirement for an indoor Wi-Fi or 5G network, then fixed infrastructure will also be needed.

Wireless antennas and access points in larger indoor networking solutions will need connecting by cable to a distribution point (for example a cabinet on each floor of a hospital), from there to a central distribution point (for example a communications room in the basement), and from there to the local area network or to the internet from where the wireless network will be managed.

The size and scale of the fixed infrastructure required will vary depending on the size and scale of the building. However, it is essential that the fixed infrastructure requirements of a wireless network (which may include vertical risers), are considered at the earliest stage of a new build or major refurbishment.

This section of the report describes the key considerations for fixed infrastructure for wireless communication technologies. It does not cover ICT requirements such as local area network cabling and local area network access points.

Cabling is required to connect antennas and access points to local area networks and to backhaul. ANSI/TIA-568-C provides generic standards and best practice guidance for the architecture of cabling systems in buildings.

The Telecommunications Industry Association (TIA) has also issued the ANSI/TIA-1179 standard to address the specific needs of health and care facilities. ANSI/TIA-1179 recognises that hospital and medical facilities require different amounts of network connections and cable densities.

The standard identifies eleven application-specific types of work areas, providing guidance for each. For example: ambulatory care, critical care, diagnostic and treatment.

The impact of electromagnetic interference (EMI) must also be considered in the design of the cable routes.

Cables must avoid sources of interference such as radiology equipment. Here EMI can cause the excessive retransmission of data on wired and wireless networks reducing effectiveness as a result.

Cables should not create interference. EMI can cause errors in medical equipment, leading to faulty readings, missed diagnoses, or malfunction in treatment equipment.

EMI can be reduced in several ways:Use of shielded cable which reduces the effects of EMI; use of optical fibre which is immune to EMI; routing cables away from sources of EMI; use of shielded conduits to isolate cables; and shielding the rooms and/or equipment – some rooms, such as those involved in epilepsy monitoring, are RF shielded and all cables into the room pass through an EMI filter.

Cable plant requirements should be considered at RIBA Stages 0-4 for new builds and major refurbishments. This will reduce the challenges faced in the design, engineering and installation of wireless networks. The factors to consider include:

• providing adequate riser facilities between floors to support vertical cable plant
• providing adequate horizontal pathways to antenna locations
• avoiding installing drywall ceilings with little or no access panels
• providing adequate AC/DC power and cooling in IDR/SDR to support active equipment
• documenting the location of all fire-rated partitions
• avoiding any outdated, inaccurate, or non-existent blueprints describing potential cable pathways and potential obstacles

Involving the RF expert at RIBA Stages 0-4 will ensure these factors are considered appropriately.

The routing of cables within hospitals and other health and care buildings requires special consideration.

Because of the critical nature of health applications, redundancy is often built into the systems, with connectivity provided by more than one pathway.

It is advisable to segregate cables by application and network function, either physically in the pathways or visually through colour coding the cables, in order to simplify installation and maintenance.

Spaces for running cable in hospitals can be at a premium since cables must share space with gas delivery, pneumatic tubes, and other needs that distinguish medical facilities from other buildings.

The routing of cables must also consider the requirements of infection control. Here air filtering and area segregation cannot be compromised by the cabling system. The need to avoid atmospheric contamination may require special cables with filled or blocked construction and low-gassing materials. Infection control policies may limit access to the cabling system in sensitive areas. Other policies may place strict rules limiting access to the pathways (plenum spaces for example) for reasons of health and safety. Thus, even lifting a ceiling tile may require careful scheduling.

High-voltage wiring and highly sensitive gases and fluids will be encased in closed conduits in their pathways. Therefore, open cable trays offer a clean and convenient way to route low-voltage communications cable through pathways. They prevent accumulation of debris during and after installation and are available in stainless steel. The open structure makes it easy to ensure correct separation of cables by visual inspection. It can also reduce crosstalk or other electrical performance negative influences.

Coaxial cable

Indoor wireless networks may require coaxial cable, sometimes known as coax cable, to transmit RF signals from one point to another. It is typically used in the building distribution room and in service distribution rooms. As coaxial cables are thicker, they occupy more space in cable trays, and are more difficult to install, for example, they require more space when curved around a corner.

Thick coaxial cable (for example 7/8" Feeder Cable) is usually used to minimise signal loss and has excellent electrical features such as low damping and reflection coefficient since it incorporates high foaming polyethylene insulation technology. It is used in many applications where it is necessary to transfer radio frequency energy from one point to another such as in-building distribution systems and antenna feed lines for various wireless communication systems.

Thin coaxial cables (for example, 1/2" feeder cable) can also be used for in-building distribution systems and various wireless communication systems. It also has the advantage of consuming less space in the cable tray and being easier to install than 7/8".

Ethernet cable

Power over ethernet (PoE) cables are practical and convenient for the installation of RF network antennas, small cells and access points because a single cable can carry data and provide power. Factors to consider when selecting PoE cables include:

• conductor size: larger conductors decrease resistance which generates less heat in the cable. This is an important factor to consider for transferring power over distances
• copper core: cables with a pure copper core cause lower signal degradation
• heat rating: selecting cables with an appropriate heat rating prevents them getting too hot when transferring data and power, which reduces performance

The main obstacle when using PoE equipment is that the quality of the data transfer starts to degrade once the cables reach a certain length.

Therefore, the ANSI/TIA/EIA 568 standards, commercial building telecommunication standard, limits the length of Unshielded Twisted Pair (UTP) cabling to 100 metres in length. That length assumes up to 90 metres of solid-core (better performance, but fragile) horizontal cable, and no more than 10 metres of stranded (poor performance, but less fragile) patch cord divided between both ends.

The higher frequencies used by modern networks require strict compliance with the standards and specifications to operate effectively. The correct installation of cables is critical, as is ensuring that the same category of components are used throughout a cable run. Each cable run must be thoroughly tested to meet or exceed all of the criteria in the test suite for that category of cable. Simply connecting the two ends of a cable is not sufficient.

The following table describes the specification of categories of ethernet cable at the time of writing.

Table 4: Specification of ethernet cables

There are 2 common types of distribution room:

• building distribution room (also referred to as comms room)
• service distribution room

The service distribution room (SDR) is a free-standing or wall-mounted rack for managing and interconnecting the telecommunications cable between end user devices and the building distribution room (BDR).

In hospitals, it is highly recommended to have at least one SDR per floor. For example, an SDR might be located on each floor of a multi-floor building routing the cabling down the walls to a BDR on the first floor. Typically, SDRs are centrally located on each floor within a facility and become a wiring medium management point between horizontal cable runs to antenna points on the floors and vertical cable runs to the BDR.

The BDR would contain cabling that would interconnect the backhaul cables to other floors within the same building. It is further recommended to have both horizontal and vertical cable paths necessary to support the potential wireless networks needed for the hospital.

The BDR is typically co-located in the basement level of a facility within a telecommunication/ server room and becomes the wiring demarcation between multiple SDRs located throughout the facility and the RF signal sources or data application servers.

Floor space and/ or wall space must be provisioned in the SDRs/BDR to accommodate cable terminations and interconnects. In most cases, and to systematically support and manage the cabling infrastructure, various sizes of telecommunications equipment racks are employed in the SDRs/BDR to support: the various active/passive equipment; AC/DC powering equipment; cable termination hubs; wireless service provider bi-directional amplifier or micro-cells; emergency power backups; telecommunications interfaces.

For cable installation purposes, adequate horizontal and vertical cable pathways must be clearly identified and readily available to support the targeted wireless technology.

Commonly, vertical cable conduit is employed between floors to support the interconnection and homing of multiple SDRs to a single BDR location. Depending on the cable medium utilised, ample space must be readily available via conduits to support the vertical cable plant. Furthermore, if fibre is being employed in the conduit between the SDR and BDR in support of the wireless technology, additional innerduct within the conduit to protect the fibre against future potential cabling installation damage must be considered.

Likewise, horizontal cable runs must be clearly identified to obtain precise antenna locations for optimal RF propagation. Horizontal cable pathways must be clearly identified and unobstructed in order to ensure the cost-effective installation of the cable plant from the SDR to the antennas on the various floors.

The following table provides an indicative cost of the hardware and installation of Wi-Fi and 5G networks within different categories of building.

Table 5: Typical wireless network installation costs (March 2022)

Small size surgery or clinic 

Medium size clinic or hospital or care home 

Large hospital