## 5 Challenges, Open Research Problems, and Future of WBANs
### The Future of WBAN Systems  
In order to exploit the features and benefits of WBANs in the future for the medical environment, it must include the following significant improvements design and features according to [113-116]:  
* Low cost and low size sensor node electronics design with wireless capability. Sensor nodes will be able to transmit data at a distance of several meters. Sensor nodes must be miniaturized so that they can be easily wearable or implantable. * Energy optimization methods should be developed by the combination of the link and physical layer functionality for wireless devices, which leads to provide longer battery lifetime and thus extends the lifetime of the sensor nodes. Sleep mode method should be used so that the sensor nodes will spend most of their time in a state of low consumption of electricity, when data transmission is not required. * Physiological data must be classified as crucial and noncrucial data for each patient. As an example, although it may be different with different patients, vital signals as electrocardiograms may be more important than the temperature for some patients. Thus WBANs system must give priority to the important data. * High gain miniature antennas should be designed for sensor nodes to increase the transmission reliability and to minimize interference, thus reducing the energy consumption. * Each sensor must be optimized in accordance with its characteristics using a variable sampling rate. * Unlike other systems, in the sensor network in a WBAN systems, each sensor signal has a different frequency (_i.e._, not uniform) and thus each sensor node must be optimized in accordance with to the frequency band of its sensor. In addition, given that some not important physiological signals such as temperature information can only be measured over longer period of time, WBANs will lead to better performance, if the \"adaptive\" communication protocol is used to accommodate such differences in the system, which will certainly make the system efficient power. * In order to ensure continued remote monitoring of WBANs, multiple gateway devices must be designed to interface with existing wireless systems in healthcare area. These gateways will mainly be used for communication between the CCUs and the remote computers or mobile devices. * A transmission mechanism should be integrated into WBANs, which could be useful for the free movement of patients in large medical applications. It can be used to track patient throughout a hospital or the patient can keep track of the places where they are outdoors doing their daily activities. An alarm feature can be enabled if the patient leaves the room or goes out of range of a CCU. This may give the last location of patients, which would allow staff to easily track the location of the patient location. Such features could be incorporated into the detection system of signals through multiple remote stations, which are generally known as soft handover. * Additional essential component in WBANs is security. Basic software components must be identified and developed to accommodate secure and efficient wireless network. Data should be only accessible by only an authorized person in remote destinations. Hardware components and software programs should be coordinated together to provide secure and reliable communications. * Personal health monitoring systems were used only for data collecting. Data processing and analysis are performed offline, which makes such devices impractical for continuous monitoring and early detection of health disorders. * Systems with multiple sensors for physical rehabilitation often feature unwieldy wires between the sensors and the monitoring system. These wires may limit the activity of the patient and level of comfort and thus negatively affects the measurement results. * Individual sensors often operate as standalone systems in WBANs and usually do not offer the flexibility and integration with third-party devices.