Wireless Alarms: Commercially Acceptable?
Across a range of commercial sectors, wireless technology has become a mainstay. End users enjoy the flexibility, the benefits to installers and integrators are obvious, and R&D continues to improve performance. Should the security sector move towards greater use of the technology in commercial applications?
In recent years, the electronic security sector has seen wireless solutions undergoing something of a renaissance, and with good reason. Long gone are the days of frustratingly intermittent stability, poor product performance and questionable quality. With advances in modern wireless technology, coupled with enhanced system design, the security sector now has all the tools needed to deliver stable, robust and effective wireless products.
Wire-free security systems offer obvious advantages over their hard-wired counterparts. With speed of installation dramatically improved, greater freedom with regard to device positioning, avoidance of damage to a site resulting in less time ‘making good’ after an installation, reduced requirements for wiring and advantages when upgrading or refurbishing a system, it is clear why wireless technology has started to find favour with engineers and users alike.
Many in the security industry may have memories of unreliable wireless products causing problems in the past. However, developments in other sectors mean that end users nowadays expect wireless products to perform. With the exponential rise of advanced communications connectivity, users are increasingly technology-savvy and – given the relative reliability of wireless in other solutions, including some life safety systems – few have qualms over acquiring a wireless security system. Embracing the technology makes sense on a number of levels.
It is fair to say that over the lifespan of wireless technology in the security sector, the quality of systems has varied enormously. In the past, RF-savvy design engineers were few and far between, and that, coupled with the cost of creating resilient wireless solutions, was reflected in the performance of early wireless systems.
Whilst wireless solutions are typically more expensive than hard-wired options, radio-based security systems were predominantly developed for residential applications.
Even today, many engineers and system designers still see wireless solutions as a choice for residential applications. The quality of modern systems means that robust, reliable wireless products are now commonplace. Despite these advances, the technology is not an automatic choice when considering commercial applications.
With commercial sites, the demands with regard to performance placed on electronic security equipment is far greater than in residential installations. The environments are typically harsher, the number of devices and size of the system are greater, and the risk (and potential cost) of a security incident is significantly higher. In such conditions, challenges need to be faced to ensure continuity of performance.
Battery life can be an issue for commercial wireless devices, which in turn leads to a need to conserve power. In order to minimise power usage, wireless devices typically spend the majority of time in a dormant state. This can create issues if the system is not specifically designed to handle a large number of devices.
Commercial premises can be large in size and can be constructed from materials that are not ideal for the free transmission of radio signals. Also, a commercial application might require a high number of devices to deliver full coverage. These factors will create issues for a wireless solution which has not been specifically developed for commercial applications.
Basic systems typically use point-to-point communications. With a single signalling path available, devices are susceptible to being ‘lost’ if there are changes to the building infrastructure. Even something as simple as the addition of a metal filing cabinet could cause disruption.
Finally, for the engineer, commercial wireless solutions can lead to more complex site surveys. In order to verify the positioning and reliability of wireless communications, a site survey is essential. With larger and more complex applications, it is vital that systems deliver a good degree of diagnostic support.
For all the benefits of wireless technology, these issues may seem to tilt the balance towards hard-wired systems. In the past that was the case, but recent developments make such thinking obsolete!
The right solution
Today it is possible to deliver reliable wireless systems in commercial applications. Whilst a combination of intelligent system design and higher-grade products is required, manufacturers have addressed many of the traditional issues, and even built in a number of additional benefits. With careful system selection and consideration of basic design criteria, wireless systems are providing significant benefits, even in harsher environments.
Two-way radio-based signalling is a must for commercial environments. It simply cannot be considered wise to implement a basic point-to-point solution with one-way transmission. If the control panel can’t identify the loss of a device from the system, or a device identify that it must retransmit alarm data when the signal does not get through to the panel, performance can only be flawed.
Many manufacturers offer hybrid systems which combine wire-free functionality with established hard-wired products to create a ‘best-of-both-worlds’ solution. Where cabling is difficult to deploy, or where a hard-wired approach might result in compromise, wireless technology can be used. However, the core of the system can be retained in a hard-wired format.
Hybrid systems can often utilise powered hubs to overcome any range limitations of wireless communications. These are powered devices that receive wireless communications from devices and repeat the information to the control panel across the wired part of the system. Multiple powered hubs (or nodes, expanders, portals or whatever terminology a given manufacturer tends to use) can expand both coverage and the overall number of wireless devices.
Mesh-network technology is a more recent technological advancement for wireless security systems. With a mesh-network system, each device is capable of acting as a repeater, receiving and repeating wireless transmissions from other devices. In this scenario, the size, scalability and range of the entire wireless security system are extended, as the signals can hop from device to device. This enhances reliability, as diagnostics constantly assess the connected devices to identify the best routes for signals to the panel. If an obstruction exists, the system simply reroutes the data traffic!
Additionally, two parts of a site can linked via a single device, delivering wireless protection to areas that traditional systems simply cannot support!
The world of wireless alarm systems has changed significantly in recent years, and with the right system the benefits can be applied to commercial applications without any performance compromise. The wireless renaissance has arrived; the benefits are too good to ignore!
|Caught in a Mesh
Wireless mesh networks are not new; they have been in use for high risk applications such as military data transfer, critical connectivity and advanced communications for many years. As is typical with technological development, the lifecycle of wireless mesh devices has seen size, power requirements and costs fall, to a point where today the technology can be utilised in intruder alarm systems.
This isn’t to say that it’s simply a case of picking up mesh network technology and dropping it into the alarms sector. If anything, size, power requirements and cost are more sensitive in the security sector than in many higher risk networking environments.
Mesh networking uses what is best described as a multi-path interconnecting topology. Each device is required to process and transmit its own data, as well as acting as a relay point for the transmission of signals from other devices. Effectively, every device on the system is also a part of the transmission path for signals and data.
A mesh network routes its data signals along a variable path between the device which has created the signal and the receiver, in this case the control panel. It does this by effectively ‘hopping’ from device to device until the alarm data arrives at the panel.
Mesh networks are self-healing, in that if a loss of communication occurs, the system can assess the situation, and reroute alarm data. The system polls connections, and will reconfigure data routes around lost paths to ensure that the signal always arrives at the control panel.
Self-healing ensures that the system will operate as specified, even if a wireless link is lost, or if a device which is part of the transmission path fails. For example, if a temporary object that blocks radio-based signals, such as metal racking, is introduced to an area between a control panel and a specific device such as a detector, a traditional wireless alarm system might lose contact with that detector. If an event occurs, the signal will not arrive at the control panel. A self-healing mesh network will realise that the connection between the detector and the panel is lost, and will then send the signal via other devices with which it can communicate, effectively working around the blockage.
Traditional basic wireless systems rely on simple point-to-point communication, where each link is made directly between the control panel and the device. This communication is one-way, meaning that the device cannot tell whether the panel has received the data as signals only flow into the panel.
Even in two-way systems, the panel might be aware that it cannot communicate with a device, but it does not know what the status of the device is. Obviously, in intruder detection alarm systems, this is not acceptable.
By creating a mesh network of interconnecting points, signal integrity is preserved, even in the event of interference or link loss. However, there is another benefit of mesh networking.
Often, sites might have areas, or sub-systems, which simply cannot sustain wireless connectivity with the control panel or main system. This might be due to dense walls, being located in a cellar, or even an area with metal shutters or walls. If there is an accessible path which is not direct, a device can be fitted (even something as low cost as a door contact) to effectively reroute the signals. This removes any ‘line of sight’ issues and delivers greater flexibility when creating a solution.