Jos van der Loop, Product Marketing Manager, Low Energy & VoIP Division, Dialog Semiconductor
A new generation of low power, self-configuring network devices capable of remote management via a web connected smartphone or tablet PC are set to deliver the next healthcare revolution.
The cost of providing healthcare to those recovering from illness or surgery has risen rapidly in recent years and there is now a significant pressure being placed on hospitals to release patients earlier, freeing up bed space and reducing costs. The desire to recover in familiar surroundings, and be close to family, has also led to this being a favourable option with the patient.
Yet it has remained limited to relatively few people and conditions, with figures from the US social medical insurance organisation, Medicare, stating that nearly 90% of those elderly and disabled patients in receipt of home care suffer just five conditions: circulatory disease (31%), heart disease (16%), injury and poisoning (15.9%), musculoskeletal and connective tissue disease (14.1%), and respiratory disease (11.6%). To enable a greater number of patients to receive home healthcare, clearly technology must be put in place to enable the monitoring of a greater number of conditions.
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If the number of conditions eligible for home treatment, and therefore the number of outpatients, is to increase the technology needs to be robust and several elements must be in place:
Web connectivity:Home care medical systems must be connected to the web, enabling easy remote monitoring by medical professionals from anywhere, via a 3G and WiFi connected tablet PC or smartphone. In addition, the web connectivity offers wide band voice connections up to 8KHz audio bandwidth.
Auto-configuration:There must be a great number of systems capable of monitoring a diverse range of symptoms, from sphygmomanometers for patients with blood pressure complications to blood sugar monitors for diabetic patients, these systems will likely come from a large number of manufacturers and must all connect with the same base station, therefore a single standard must be used, and this standard must allow for the auto-configuration of new devices as they’re added to the network.
Low power and low interference design:To prevent any risk of clinical incidents, reliability is essential. Devices must be able to update constantly and warn of potential complications as they arise - with time for an ambulance or travelling nurse to arrive promptly to deal with these. This means signals cannot be affected by other wireless networks that use the same frequency. It also means that a low power wireless standard must be selected to avoid battery failure.
One of the key emerging standards for such applications is the new ultra low power variant of the robust and proven DECT protocol (DECT ULE).
What is DECT ULE?
At a basic level ULE adds fast switching to the devices enabling a standby or deep “sleep” mode, only waking when a pulse is given by the internal counter (for battery check) or from external events.
Like standard DECT, it operates in the 1880 to 1900 MHz frequency band (outside Europe the 1910-1930 MHz and 1900-1920 MHz bands are also used). This 20 MHz of radio spectrum is split into ten channels with a spacing of 1.728 MHz. In addition to this division by frequency (Frequency Division Multiple Access or FDMA), DECT also splits up the available space into time slots (Time Division Multiple Access or TDMA). In total, there are 24 time slots per frequency band (12 “down” and 12 “up”). And 100 frames per second can be sent over each of the ten frequency bands.
To transmit data, DECT equipment first scans the entire DECT band and selects a channel by choosing a specific time slot combination on a specific frequency. For instance, after scanning it may decide that downlink slot 2 and uplink slot 14 in frequency band 2 (1888.248 MHz) are available.
With twelve possible time slot combinations and ten frequency bands, there are a total of 120 radio channels available. The total capacity can be extended further by adding more basestations. As long as basestations are far enough apart so as not to disturb each other, each one can manage its own sector. In this way, hundreds of thousands of users in a single office environment can be supported. What’s more, unlike many other low-power technologies, there is no need for frequency planning because the system dynamically selects the best channel to use.
Benefits of DECT ULE for medical applications
DECT ULE is an exceptionally wireless robust transmission protocol, which is essential in achieving healthcare product certification. Like the DECT standard, DECT ULE devices automatically configure with a base station unit to create simple star networks with over 100 connections, meaning new home healthcare system products can be easily added to a home’s network.
Additionally, by operating in the 1.9GHz spectrum, the standard doesn’t suffer interference from other wireless networks - reducing the chance of failure - and, unlike standards using 2.4GHz, DECT ULE base station chips can be integrated into a home’s WiFi enabled broadband router, allowing DECT ULE wireless sensor network devices to easily connect with the web for remote monitoring of symptoms - indeed many broadband gateways already integrate DECT chips that, following a software upgrade, work with DECT ULE systems. Finally, healthcare professionals and family will be able to manage DECT ULE healthcare systems remotely via a smartphone, laptop or tablet PC.
The diversity in DECT ULE applications also brings additional benefits that allow patients to stay at home and recover faster. Home healthcare devices are not solely those that monitor a patient’s symptoms, a true home healthcare system enables greater control for the user. For example, patient communication systems are truly vital, and the DECT ULE standard enables the transmission of 232 bit data and high quality, wide band audio, ensuring nothing is missed during contact with medical professionals or service centre used to monitor vital signs. Furthermore, DECT ULE can be used to create a wide range of web connected home automation systems, one such example is a door lock actuator, allowing a nurse to more easily gain access when a patient’s mobility is limited. This can be done from either the nurse’s tablet PC, or via a patient’s dedicated control device.
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Application example: Personal Health Button (PHB)
The company Viadact which is part of the Guard on Line family of companies, is a Belgian based provider of healthcare service solutions for care homes, hospitals and call centres and has recently launched one of the first home health communication devices that benefits from this new technology, the Personal Health Button. This wireless alarm pendant and base station integrates Dialog’s DECT ULE offering, SmartPulse, and enables users to alert nurses or family members of incidents at the press of a button. Contact can be instantly made and an incident assessed more accurately, meaning the appropriate response is taken more quickly.
The device has a range of 50m inside and 300m outside, so it can be used anywhere in the home or garden and the PHB has been designed to be usable at all times - including when in the bath or shower. Furthermore, the base station unit is simple to install; once connected via Ethernet to a home’s broadband router the device automatically establishes a secure connection with the correct server and uses 8kHz wideband VoIP to provide crystal clear audio quality.
Additionally, the system enables data transmission to communicate with other SmartPulse and DECT ULE devices throughout the home, allowing the patient, or nurse, to control almost anything, from light switches to door locks. Alerts for lost connections and low batteries have also been created and, as reliability is essential, GSM and PSTN fall back connectivity options are also implemented to enable continuous operation, even when the power grid goes down.
PHB in action
Once the PHB system is triggered, whether via a patient initiated request or via the system’s ‘listen-in’ safety feature, medical care professions can determine the level and nature of the problem before sending out a locally based emergency response nurse if applicable. Once at the home the nurse can talk to the patient using the PHB’s doorbell intercom link. Finally, using the PHB system the patient can give access for the nurse to enter the home, unlocking doors with DECT ULE actuators that control the locks – because the PHB system connects to the web, the nurse is also able to connect with and activate the door locks using an encrypted tablet PC or smartphone application should the patient be unconscious.
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Door-lock control is an essential feature. According to our care institute end customers, elderly people can often fall in hurried moments, for instance at the point of opening doors with keys. To minimise this risk care institutes, such as the Belgian firm Wit-Gele Kruis, often keep the keys in a nearby safe – a solution that, it is reported, is seen as far from ideal by nurses performing home visits.
The PHB is the first commercialised healthcare product in Viadact’s roadmap that uses SmartPulse. In developing the PHB, Viadact tested a wide range of wireless standards with the range and the network capabilities of the SmartPulse wireless system proving decisive for the choice of radio technology, according to Johan Fransen, CEO of Viadact
Long battery life
Of course, to avoid clinical incidents from occurring, failure is not an option. Battery life must be long as a door-lock, monitor or communication device that fails due to weak batteries could prove fatal for the patient. SmartPulse devices deliver up to 10 years of service from a single AAA battery pack: using just 5C per transaction and 3µA in sleep mode - based on six communications per hour to alert the base station that all is working well.
DECT ULE Implementation
The PHB is among the first devices to benefit from DECT ULE technology and the market is anticipated to grow rapidly.
Lisa Arrowsmith, a Senior Analyst in IMS Research’s Connectivity Group has reported that DECT ULE enables a variety of in-home applications – citing home health monitoring along side security, and home automation. “DECT technology has already proven its performance in residential environments, and the emerging DECT ULE standard will benefit from the maturity of previous DECT solutions, in terms of both technical development and consumer awareness. With low sleep-mode power consumption and a range well-suited to residential environments, IMS Research projects rapid uptake of the DECT ULE standard for wireless sensor networks.”
Dialog Semiconductor launched the industry’s first commercially available family of DECT ULE IC based devices in September 2011. The suite of products consists of the SC14WSMDATA (data) and SC14WSMDECT (data and audio) wireless sensor nodes, and the SC14CVMDECT base station device that can be integrated into standalone hub products or internet gateways - allowing the remote management of SmartPulse enabled systems over an internet connection.
The 25x29mm, 123-pin packages meet certification standards for all global markets – FCC, EU and J-DECT and are available in high-volume quantities. Furthermore, SmartPulse devices are backwards compatible with standard DECT, enabling SmartPulse sensor nodes to communicate with existing legacy DECT enabled hubs and internet gateways from multiple manufacturers, with a simple software update.
Dialog development kits and reference designs
To help accelerate product creation cycle, Dialog offers complete development kits for all SmartPulse™ modules. The wireless sensor module kit includes a SC14CVMDECT-based base station, a SC14WSMDATA development board (featuring a module, various interfaces, battery and power connector) and USB cables. Also included is demonstration software, application examples and the Athena IDE, enabling rapid application creation.
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SmartPulse reference design and dev kits enable rapid development of remotely managed home automation systems
Dialog’s DECT IP base station reference design kit offers easy prototyping of internet-enabled DECT ULE systems. The kit features a DECT IP base station that combines a SC14CVMDECT for base station-node communication with one of the company’s energy-efficient VoIP processors for hassle-free internet connectivity. It comes complete with example sensor and actuator nodes based on the SC14WSMDATA wireless sensor module, plus the Rhea μClinux-based VoIP software development platform.
The Athena Integrated Development Environment (IDE) is an easy-to-use, open-source toolset for creating new application software. It features an Eclipse-based IDE, a GNU C/C++ compiler and linker, and a code download and verification tool – all preconfigured and tested to work straight out of the box.
The cost of providing healthcare to those recovering from illness or surgery has risen significantly in recent times and this has led to many healthcare organisations around the globe seeking alternatives that allow patients to recover in comfort at home. The move frees up bed space and reduces cost. It is also extremely popular with patients, who prefer to recover in familiar surroundings and with greater access to family members.
New technologies are making it easier to remotely monitor a greater number of patients and classes of conditions, meaning home care is set to become more prevalent. But, healthcare providers and device manufacturers must get the technology decisions right if patients are to truly benefit from such systems.
Dialog’s SmartPulse DECT ULE wireless sensor network devices enable the creation of robust systems for home healthcare applications. Using the 1.9GHz licensed band means that interference is minimised and the standard’s efficiency enables long battery life, minimising the risk of failure and clinical incidence.
The standard enables devices to easily connect to and interact with other DECT ULE home automation and healthcare systems. Being a tested, robust and trusted standards-based communication protocol, it is simple to configure devices, from door locks and light switches to blood sugar monitors and sphygmomanometers. Furthermore, devices based on the technology connect easily with the web, enabling effective communication with medical professionals and allowing the remote management of such systems from a computer, or smartphone / tablet PC application.
Home healthcare will certainly prove to be cost efficient for the health service providers and become a more acceptable form of after-care for patients who will be able to remain comfortable and independent in their own home environment.