Ubiquitous connectivity is the future of wireless
Systems capable of seamlessly using satellite, cellular and local area networks are nowadays a must-have.
Connecting people and everything, no matter where they are, has always been the main goal of wireless communications. Whether it is people talking on their mobile phones, vehicle communication (V2X) platforms helping cars negotiate traffic turns or Internet of Things (IoT) devices monitoring smart factories, today’s wireless systems are striving to realise that dream.
This power means that ubiquitous connectivity — systems capable of seamlessly using satellite, cellular and local area networks to maintain a fast, secure and reliable online connection — is no longer a nice-to-have feature but a must-have.
For the engineers building these technologies, the challenges of designing wireless systems optimised for ubiquitous connectivity have grown along with their capabilities. These include ensuring a device’s compliance with standard protocols for system and device interoperability; optimising multidomain system parameters which integrate algorithms, antenna, array and RF transceiver design choices; and verifying the designs of hardware prototypes with automated over-the-air tests and realistic channel and impairment models.
Fortunately, techniques and best practices exist that engineers can use to design, model and test these systems, ensuring they work together to provide businesses and consumers alike with not only wireless access, but true ubiquitous connectivity.
The evolution of wireless
From a technical perspective, the concept of ubiquitous connectivity is nothing new. However, it has been a challenge to execute for economic, technical and physical reasons. Economically, the number of access points have been historically limited by cost and reserved mainly for high-density population areas.
High throughput links could not be constructed seamlessly over a variety of ranges and distances and each technology has catered to its own niche market. Lastly, physically, each communication link is limited by the interference provided by other systems using the same or adjacent spectra. This has made coordination between various systems a necessity.
While modern high-level wireless systems have overcome many of these challenges, for example: low earth orbit (LEO) satellites are more cost-effective than their medium earth orbit (MEO) and geostationary orbit (GEO) counterparts, with their signals capable of providing substantial throughputs at large distances; but other challenges remain.
5G, Wi-Fi and satellite-based communication devices, for instance, rely on multi-user multiple-input and multiple-output (MIMO) beamforming technology to reach users in the service area. MIMO and beamforming-enabled devices are equipped to send and receive multiple signals, necessitating engineers to optimise use of multiple frequency bands at once.
This, however, requires constant monitoring of available signal space and precise scheduling as well as channel modelling and measurements on both ends of the link to connect two devices.
When designing for ubiquitous connectivity, engineers have typically designated Wi-Fi systems for shorter-range and cellular systems for longer-range communications. These heterogenous types of networks can operate in tandem, so that, for example, signals beamed to a congested cellular service area can be offloaded to a Wi-Fi service network and vice versa.
Bluetooth has a role to play in ubiquitous connectivity as well. While not meant to be part of a high-throughput wireless network, the low power and ISM band usage of its basic rate, enhanced data rate and Bluetooth low energy standards makes the platform ideal for sending short-range signals.
Engineers can leverage the short-range signals provided by Bluetooth as they best indicate whether a device needs to connect to the internet. Alternatively, Bluetooth can also help engineers save bandwidth and keep devices offline when they do not need to be connected.
Ensuring each of these types of networks, broad area networks such as satellite links, cellular wide area networks including 4G and 5G, local area networks (Wi-Fi) and personal area networks such as Bluetooth, are in sync providing ubiquitous connectivity requires extensive testing. For engineers working on these problems, the extensive testing is better conducted through modelling and simulations than with live equipment. This is where the value of large-scale simulation platforms become clear.
Simulation helps engineers achieve ubiquitous connectivity
Solving the challenge of ubiquitous connectivity requires engineers to not only understand the relationships and interferences between all wireless communications protocols and standards in place today, but test the standards’ compatibility with each other. Engineers can use large-scale modelling and simulation tools such as MATLAB and Simulink to design, model, test and analyse systems before deployment, ensuring the reliability of their systems long before a physical device is built.
For example, a key challenge when developing cellular network systems is the number and complexity of parameters associated with each mode of operation. Engineers need to understand that each parameter needs to be tested against a variety of channel conditions that can occur in a typical cellular network. If all the testing conditions are not met, the system cannot be certified.
To address this, engineers can use simulation platforms to provide an environment that makes reviewing all potential parameters and evaluating them against other systems easier, faster and more reliable than physical testing. Faster testing methodologies are largely possible due to the advancement of technologies included with MATLAB and Simulink, such as: ease of test waveform generation and use of automatic C code generation, GPUs and parallel computing for accelerating simulations.
Of course, multi-user MIMO and beamforming systems are only as effective as their ability to accurately point to and connect with target devices. This necessitates simulation platforms such as MATLAB and Simulink to make the task of verifying accurate positioning and localisation easier.
These solutions not only provide engineers with industry-standard compliant tools generating individual signals including Bluetooth, 5G, LTE and Wi-Fi but also a visualisation and testing environment enabling them to see the effect of indoor and outdoor RF propagation on maps. This will help them ensure the connections between multiple devices are accurate.
Ubiquitous connectivity continues to be a must-have in the modern world. This ultimately means that simulation platforms too will have to adapt to remain essential for engineers as they design systems capable of seamlessly using a multitude of modalities including satellite, cellular and local area networks, all while maintaining a fast, secure and reliable online connection.
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