Q&As

Historically, radio signal processing was done by dedicated hardware specifically designed for each type of signal. This remains an effective approach, still widely used by common forms of wireless communication. Yet its very effectiveness limits its flexibility. An alternative approach is to build generic hardware then undertake the specific signal processing using software. This approach to signal processing is known as Software Defined Radio or SDR.

SDR is certainly more flexible than dedicated hardware, yet it conventionally requires powerful servers to process in real time the high volumes of data generated by SDR. Dedicated SDR servers are neither cheap nor cost-effective run. At the same time, the complex real time software systems that run on them is challenging to write, and hard to maintain and upgrade in a commercial environment.

Rather than rely on off-the-shelf servers, cellXica’s approach has been to develop and use its own proprietary Field Programable Gate Array (FPGA)-based hardware together with bespoke, and complimentary SDR software infrastructure. This integrated approach retains the best of both worlds without accepting the compromises. Having this deeply structured architecture at the heart of all cellXica products means we can design, develop,  implement and combine the broadest possible range of radio standards.

cellXica’s approach brings many benefits:

• Forward compatibility: SDR-based hardware can often be updated in the field
• Long life: we’re still upgrading hardware sold and installed 10 years ago
• Custom variants: if you need a special feature, we can add it
• Standards tracking, with features and performance enhanced as specifications evolve
• Self-determination: freedom from design frameworks imposed by third party chipsets and equipment vendors
• Future proofing: upgrade 4G base stations to support new 5G handsets
• Significantly reduced power consumption

cellXica’s SDR approach creates the widest possible range of benefits for specialist applications without compromising on ease of use or limiting the performance needed by mainstream commercial industrial applications.

How are they the same?

In the simplest of terms, both technologies use radio transmissions to share information – data and voice – wirelessly between people and devices. Under certain circumstances (few users, little interference, low power) Wi-Fi and cellular offer good connectivity and similar data rates. It’s the context that’s critical, which is why Wi-Fi works so well in so many everyday scenarios, but you need mobile when out and about.

Both Wi-Fi and mobile cellular technologies are defined by protocols and standards. While both use radio waves, each does so differently. Radio waves behave in different ways depending on their frequency. Lower frequencies travel further but carry less information. Higher frequencies carry more information but over shorter distances. These variations make each frequency more or less suited to different purposes, for different reasons, and underpin the characteristics that distinguish cellular and Wi-Fi.

How are they different?

Unlicensed or licensed spectrum

Wi-Fi operates in unlicensed spectrum, meaning anyone can use the same frequencies. This makes it convenient but also unpredictable; other users’ transmissions can interfere with your network at any time. Private mobile networks use licensed spectrum. Once licensed, you have exclusive use of dedicated frequencies, giving you protection from interference and full control over performance.

Range and infrastructure

Private Mobile base stations are allowed to transmit 10 to 100 times more power than Wi-Fi access points. That extra power translates into dramatically greater range; often 10 times further or more. In practice, this means you may need 20 to 50 times fewer access points (or base stations) to achieve coverage comparable to Wi-Fi.

Security and access control

Wi-Fi security typically relies on usernames and passwords, which are easily shared and hard to manage at scale. In contrast, private mobile networks use SIM-based authentication, just like public cellular networks. Only devices with a valid physical SIM or eSIM can authenticate and connect to the network. Device access can be revoked instantly, and credentials can’t be reused, giving operators complete control over who and what is on the network.

Traffic management

Wi-Fi uses an uncoordinated “listen and retry” approach. If two devices transmit at the same time, both fail and try again. This works when user numbers are low, but under heavy load it can manifest as lag (at best) and network failure (at worse).

Cellular networks coordinate transmissions centrally. The core network software decides who can transmit and when, preventing collisions and ensuring predictable performance, even when user numbers are high.

When is Wi-Fi the right choice?

Wi-Fi excels over short distances and is ideal for indoor environments like offices. It suits applications such as web browsing, where users’ demands are sporadic, generating small bursts of downloaded and uploaded data. Wi-Fi’s comparatively simple access control can also reduce administrative overheads in smaller environments.

When does private mobile make more sense?

Private mobile makes more sense in larger spaces and demanding environments. Warehouses, factories and outdoor site are a natural fit for cellular’s greater range, and with it a corresponding reduction in access points and cable runs. In high-traffic environments, a parallel private mobile network can also offload and protect critical data when Wi-Fi capacity is stretched. Cellular’s stronger authentication and access control also suits critical business processes and production systems.

Using Wi-Fi and Private Mobile cellular Together

Rather than choosing one or the other technologies many companies and organisations are increasingly using both. cellXica enables this hybrid approach by offering a range of integrated base stations and one-box network solutions, such as the M5Q Plus, that work seamlessly alongside existing Wi-Fi infrastructure. With all the required software inside the PoE++ powered box, the M5Q Plus quickly extends the reach of an existing network.

Done properly, cellular and Wi-Fi wireless connectivity solutions across indoor and outdoor industrial sites create seamless future-ready networks that optimise performance, coverage, control and operational reliability.

Understanding spectrum

In wireless communications, spectrum refers to the full range of radio frequencies (measured in Hertz, or cycles per second) used to transmit information wirelessly. Individual sections of the spectrum are known as bands.

Different radio frequencies behave in different ways. Lower frequencies (longer wavelengths; fewer cycles) travel further but carry less information. Higher frequencies (shorter wavelengths; more cycles) carry more information but only over shorter distances. These variations make each individual band suited to different purposes, for different reasons.

Why licensing exists

Slicing the continuous spectrum into bands helps with managing access. Without regulation, unmanaged transmissions would overlap or otherwise interfere with each other, rendering communications unusable.

Regulators control who can transmit on each band, as well as what it’s used. Managing spectrum in this way means the bands can be used as effectively as possible for the largest number of users. At this level, a spectrum licence is simply formal permission to transmit on a band (over a specific set of frequencies), thereby ensuring predictable radio performance while preventing interference.

So, if you own a license, no one else can use your spectrum, and you get that predictable performance.

Who manages the licensing?

Individual governments choose how to manage the spectrum in their country, while aligning with international conventions and agreements. National regulators, such as Ofcom in the UK or the FCC in the US, decide who can use which bands, for what purpose, in which locations and at what transmitter power levels.

Public mobile operators

Public mobile operators such as EE, Vodafone, Telefónica and AT&T have exclusive rights to use nationwide spectrum, buying their licences from the regulators in those countries they operate in. These licences typically cost many hundreds of millions, given their scope (the number of bands and the geographics spread). Public interoperability is achieved through adherence to the global cellular standards created and managed by 3GPP, the organisation responsible for 4G and 5G technical specifications.

Private mobile operators

In recent years, many governments have allocated separate bands specifically for use by private network operators. These allocations have enabled companies to operate private mobile cellular using 4G and 5G standards, with licensing terms typically supporting private use. For example:

• Spectrum licences allow exclusive use. Unlike Wi-Fi, no one else is allowed to transmit on your licensed frequencies within your area.
• Licences permit higher power transmissions. Private mobile networks can typically transmit at 10 to 100 times higher power outputs than Wi-Fi. Higher power means fewer base stations (the equivalent of a Wi-Fi access point), better coverage and superior reliability.
• Use of industry-standard technology. Licences are usually conditional on the use of equipment that complies with 3GPP’s 4G or 5G standards, ensuring compatibility and performance.
• Affordability. Unlike public operators, private licence holders typically pay small annual fees, usually per base station.

While every country has its own application process, coverage rules and pricing model, applying for and using private spectrum is easier and more widespread than ever before.

What about Wi-Fi and Bluetooth?

Licensing in practice