## 2 State of the Art
### Related Work
The former type includes those systems that allow for patients monitoring inside the boundaries of a specific area, usually a hospital facility, as in LOBIN [44]. The latter refers to those systems where patients can virtually have any arbitrary location (inside the coverage area of WAN technology, typically a Cellular Network technology). In \"Self-Monitoring\" systems patients can also have any arbitrary location but there is no involvement of medical specialists. In this case, patients are provided feedback on its own medical status. Some systems provide information to both medical specialists and the patient while not imposing limits on patient's location. Such systems are assigned to both the \"Wide Area\" and the \"Self-Monitoring\" categories. From the communications point of view, systems can be compared in terms of the network segments that make up their architectures and the communication technologies used in each of them. In this sense, selected projects are analyzed taking as reference model the General Communications Architecture for WHMS introduced in Section 2.1 (Figure 1). Abbreviations are used to specify the concrete communications technology used in the network segments that are deployed in each system. For non-deployed network segments corresponding fields are left blank. More detailed descriptions of selected projects follow. They are done in terms of individual tables specifying the same concepts for each system, so that the different systems can be further compared. Such concepts have been chosen with the purpose of providing the reader with a general overview of both the medical purpose and the architecture of the system, and include:  
* \"Project name/Funding\": whenever defined, the project name is used to refer to the system, otherwise paper authors are used. Funding can be provided either by specific research funding programs or by research institutions. System presentation year is also specified. * \"Target Application\": states the specific medical purpose of the system. * \"Tracked Parameters\": lists the medical parameters that the system considers classified into two different categories, namely physiological and non-physiological. For those parameters that appear in more than one system, abbreviations are used. Such parameters are:* \"Physiological\" parameters: Blood Pressure (BPr), Electrocardiogram (ECG), Electroencephalogram (EEG), Electromyogram (EMG), Galvanic Skin Response (GSR), Heart Rate (HR), Photoplethysmogram, Respiration (R), Blood Oxygen Saturation (SpO2) and Temperature (T). * \"Non-physiological parameters\": Activity (A), Acceleration (Acc), Humidity, Location (L), Movement (M), Position (P), Voice and Weight. * \"System Architecture\": provides a brief description of the main building blocks composing the system considering both hardware and software elements. * \"Communications Technologies\": states the concrete communications technologies used in each network segment of the system (\"BAN\", \"PAN/AN\" and \"WAN/Backhaul\"), taking as a reference the General Communications Architecture for WHMS presented in Figure 1. In case the system does not implement any of the network segments the corresponding field is left blank. * \"System Highlights\": in this field, peculiar features of the system are commented. System descriptions are presented in chronological order below from Tables 3-38: