Due to the fact that home monitoring systems are already a research topic for several years, there are some existing systems, which are mainly designed proprietary. Basically the systems differ in the mode of signal transfer. Since the Saphire project concentrates on wireless sensors, this section focuses on wireless systems and names only few wired systems.

The first monitoring systems to be named are built up in the United States of America. These systems use wired sensors to measure blood pressure, pulse oximeter and blood glucose. These systems only measure the vital parameters of the patient a few times a day. The measured data are then sent to the homecare provider, which then can analyze the data and give feedback to the patient (i.e. well@home, HomeMed). The systems are commercially available and are already in use.

Other projects use wireless sensors to establish the data transfer with the homecare monitoring systems. Mainly two wireless architectures are used to collect the data and transmit them to the homecare provider. On the one hand there are projects which collect the sensor data in “Body Area Network” (BAN: i.e. Personal Health Monitoring, MobiHealth). On the other hand there is a Home Care Unit (HCU) at the home of the patient. A third possibility is shown in the Citizen’s Healthcare System (CHS), where the sensors provide their own connectivity. Last but not least there are mixed architectures. Another product is realized from Biotronik in Germany. Using this product it is possible to (wireless) monitor patients with implanted pacemakers, defibrillators or other heart failure therapy systems. The data of the sensors are then sent to the “CardioMessenger”, which works similarly to a cellular telephone, which then hands over the data via an encrypted SMS to the physician.

The projects which use HCU for the collection of sensor data are listed below: The three projects WiPaM, Motiva and TOPCARE are using Bluetooth for the connection between sensors and HCU. For the communication to the homecare provider these projects apply standard communication technologies. The data transfer is done with normal phone lines (analogue or ISDN), GSM or data lines (DSL, Ethernet).

In the project IDeAS WLAN is used for the communication between the medical sensors and the Home Care Unit. The HCU consists of two parts: Firstly there is a “Set Top Box”, which can be used for the communication between the doctors and the patient as well as it is also possible to use it for the automated data transfer to the clinic. Secondly, the communications with the sensors are realized with a separate box, a so called “Vital Signal Monitor” (VSM). This VSM is connected via WLAN to the Set Top Box, so the sensor data can be sent to the provider.

In the Citizens’ Healthcare System (CHS), a different kind of networking is used. Within the CHS approach the sensor also provide the communication interfaces to the homecare provider. It is not possible to combine the different data of the sensors locally. Only the homecare provider is able to combine the data after the transfer, so that a possible feedback to the patient can only be given after the data communication.

A special project is the Universal Remote Signal Acquisition For hEalth (U-R-SAFE). It is combination of the two kinds of Homecare Monitoring Systems with wireless sensors. The project separates two different scenarios: On the one hand side they use the BAN technique if the patient not at home. On the other hand side they use the HCU technique if the patient is at home. So it is possible to monitor the patient 24 hours online.

There are two more projects and products which have to be named, respectively. The first one is doc@HOME, which applies a home monitoring device based on a microcomputer with Windows CE. The second one is from Dr. Hein GmbH in Germany. They use some homecare products which they combine to realize the HomeCare system. The basic infrastructure is divided into the “EvoPhon”, a video phone system that works with a television, and the “EvoCare”, a health care system which has got an option for homecare. Additionally to the video phone and sensor data collection, there is a “Brain Jogging” module, which should train the brain by asking questions and a “Keep fit” module, which is a physical trainings program system. Planned are modules for “Smart Home”, health information services and home banking.