Why is there no mobile signal inside my building?
Because the building is doing its job.
Mobile signal is radio, and radio does not pass easily through the materials modern construction is made of. Four things account for most of it:
- Reinforced concrete. The steel inside the slab and the core acts as a barrier. The thicker the structure, the more signal it absorbs.
- Low-emissivity glazing. Energy-efficient glass carries a thin metallic coating that reflects heat, which is exactly why it is specified in Saudi. That same coating reflects radio. A fully glazed tower can be one of the worst buildings for indoor signal, not the best.
- Metal cladding and insulation. Foil-backed insulation and metal facades behave like a shield.
- Depth. Basement parking and lower ground floors are below the level any outside signal reaches.
None of this is a fault. A building specified for thermal performance in a Gulf climate is, almost by definition, specified to block radio as well. The two problems have the same cause.
How is it fixed?
A donor antenna on the roof or facade picks up the existing outdoor signal. That signal is carried to an amplification unit, then redistributed inside the building through coverage antennas placed where people actually are.
The important part is what sits in the middle. A crude repeater simply amplifies whatever it receives, including noise, and can push interference back into the operator's network. That is why uncontrolled boosters are a problem for operators rather than a solution.
CEL-FI systems manage their own gain, adjusting continuously to avoid feeding interference back into the network.
The CEL-FI range Nextivity lists for Saudi Arabia runs from GO smart signal boosters for homes and smaller spaces to QUATRA active distributed antenna systems for larger buildings, where a network unit feeds coverage units spread across the floors. Nextivity states that its Saudi solutions support all Saudi mobile and virtual network operators.
Are signal boosters legal in Saudi Arabia?
Yes, as long as the system is licensed and meets the regulator's specification.
Mobile signal boosters in Saudi Arabia are regulated by the Communications, Space and Technology Commission (CST, formerly CITC). Its Regulations for Selling and Using Mobile Signal Repeaters state that using boosters which are not licensed by the Commission and do not comply with its technical specifications is against the Telecommunications Act, because they degrade mobile network quality.
The technical requirements are set out in CST's Specification for Mobile Repeaters (Mobile Signal Boosters), which CST updated by Decision 545/1445. CST's rules cover both provider-specific repeaters and multi-operator repeaters, and Nextivity states that its CEL-FI products conform to CST's regulations for both.
The practical point for a building owner is simple: specify a system that conforms to CST's specification, not whichever repeater happens to be available.
How much area does one unit cover?
There is no single figure, and any supplier quoting one without asking a question first is guessing.
Coverage depends on the strength of the donor signal outside the building. A system with a strong, clean outdoor signal to work from covers considerably more internal area than the same system fed a weak one. Two identical buildings on opposite sides of the same district can need different designs.
The other variables are the building itself: floor plate size, how the space is divided, what the internal walls are made of, and how far below ground the lowest level sits.
At the top end, Nextivity describes the QUATRA family as scalable to around one million square feet, roughly 93,000 square metres, across a site. That is a ceiling for a full system, not a per-unit number.
This is why the process starts with a site survey that measures actual signal strength at the building rather than estimating from a map.
What does a survey involve?
Someone measures the existing signal at the building: outside at the proposed donor position, and inside at the points that matter. That produces the actual signal loss figures for that structure, which is what the system is then designed around.
The survey is also what establishes whether a booster is the right answer at all. Where there is no usable outdoor signal to amplify, amplification is not the solution and a different approach is needed.
When should this be designed in?
Earlier than most people do it.
Coverage systems need cable routes from the donor antenna to the amplifier and from the amplifier out to every coverage antenna, plus a position for the equipment and a power supply. Those are the same coordination decisions as any other building service, and they are far easier before ceilings close.
The common pattern is the opposite: the building completes, tenants move in, complaints start, and the system gets retrofitted through finished ceilings at several times the cost and disruption.
Basement parking is worth deciding early for a separate reason. It is the area most likely to have no signal at all and the area where people most expect their phone to work, particularly a resident arriving home or a driver waiting.