## 1 Introduction  
The advancement of the human race has been driven to a great extent by the innovation, expansion, and diffusion of new technologies, which play a central role in modern societies by enhancing social welfare and defining new ways for humans to interact with their environment. In the last century, humans achieved unprecedented levels of comfort and wellbeing. Naturally, this progress was due to the large scale introduction of technologies in all aspects of human existence.  
However, the exploitation of our resources is not sustainable, and if we continue the consumption of energy at the current levels, then it may cause the end or at least a pause in the prosperity cycle we have been accustomed to since the beginning of the last century. Besides, our society faces serious challenges which jeopardize our model of economic and social development. As a consequence, mankind has to find a way to rationalize existing resources. The change in our habits is inevitable.  
Society is gradually getting older; we are witnessing the growth of an aging population and a significant reduction in the birth rate. Given this scenario, within medium- and long-term horizons, states will not be able to afford the expenses since this is going to place a huge burden on the health care systems, and the pressure and demands on the health care providers will increase. Therefore, medical care for the elderly has become a major health and ethical issue and a critical part of government policy [1]. On the one hand, we have an unsustainable pattern of energy consumption and, on the other hand, we have an aging society.  
An emerging idea to overcome such challenges is to transfer part of these responsibilities to common citizens, to enable them to play an active role in the collective effort of rationalization.  
In recent years, a new paradigm that allows people to manage consciously home energy resources and to improve their behaviour in order to reduce energy consumption is the smart home. This concept, which could be the answer to the challenges stated above, has gained importance due to four factors [2]: (a) the fast progress and miniaturization observed in semiconductor technology resulting in a proliferation of computing and electronic devices in our everyday lives; (b) the exponential growth of microcontrollers unit (MCU's) processing power; (c) the integration of advanced signal conditioning in very small sensor nodes that can measure and store data using complex processing techniques; and (d) the rapid development and progress of wireless technologies, essentially short range and low power applications. All four factors are generating remarkable possibilities.  
As life expectancy has risen significantly over the last century, and people enjoy more satisfying lives, they desire as much independence as possible. However, autonomous lifestyles bring new demands and challenges. One is a constantly aging population and the other is the unsustainable habit of energy consumption; both require new ways to manage this apparently impossible problem.  
The smart home concept is based on the interaction between services and features. This idea results from a convergence of several areas: entertainment, security, energy management and health care.  
The smart home paradigm can be the answer to such demands since the residence is equipped with technology that observes the inhabitants and provides proactive services that can deliver comfort, security and safety, energy saving and sustainability, and home care.  
In this work, we intend to survey the characteristics of wireless protocols, in order to determine the strengths and weaknesses of each of the communication protocols. With the knowledge of these characteristics, it is possible to integrate the communication and collaboration capabilities of the various systems and devices within their habitat to reach a common goal.