## 5 Remote Monitoring Technologies
It employs a 250 kbps 2.4 GHz IEEE 802.15.4 radio protocol, with 15 Bytes per second maximum data rate per miTag and an augmented wireless range of 200 m indoor/400 m outdoor, which is similar to other specialized wireless sensing platforms (known as motes) [117]. This platform can sustain a range of commodity sensors, including GPS, pulse oximetry, blood pressure, temperature, electrocardiogram, to name a few, with the patient data being relayed over a self-organizing wireless mesh network. In the pilot trials, the system was shown to adequately and significantly increase the patient care capacity, reliably transmitting patient-related data within radio-interference-rich critical care settings [118]. MEDiSN wireless sensor network which uses miTag was also shown to tolerate high degrees of human mobility [117]. An exciting prospect, a sensor network of this size and complexity requires good understanding of the network dynamics, including the capacity of a routing protocol to respond to node malfunction and breakdown [111,119]. While employment of simulators and testbeds facilitate the advancement, debugging, and spatio-temporal analyses of the sensor networks, e.g., determining the power consumption, these tools are unable to fully account for the complexity of radio channel characteristics, environmental stimuli, node mobility, and hardware failures of a real life network [119, 120, 121, 122]. Several passive external tools capable of observing, recording and reconstructing of critical aspects of complex sensor networks _in situ_ have been proposed, including LiveNet developed by scientists at Harvard University [119,123]. LiveNet uses passive monitoring of radio packets recorded by packet analyzers co-deployed with the network. Traces intercepted by multiple packet analyzers (sniffers) are agglomerated to construct a global behavioral picture of the network to which a range of analyses can be applied to determine application behavior, data transfer rates, network topology, routing protocol dynamics, and packet loss [119]. When applied to a 184-node sensor network testbed used to monitor vital signs of patients during a emergency drill, LiveNet was able to correctly reconstruct the topology of the network, established bandwidth usage and routing paths, discover hot-spot nodes and sources of packet loss [119]. Compared to traditional network monitoring systems, LiveNet has a number of advantages, including (i) decoupling of packet interception from trace analysis, allowing for the as-captured packet trace analysis; (ii) performance and reliability of the network being investigated is preserved due to no changes to the network required; (iii) the infrastructure for the non-intrusive monitoring is installed, reconfigured, and dismantled independently from the network being monitored, and thus can be used on a need-to basis; (iv) the monitoring system can be employed to monitor mobile or physically inaccessible sensor nodes. Nonetheless, LiveNet and similar monitoring systems are faced with challenges, including insufficient coverage of sniffer infrastructure with respect to total number of packets intercepted; the trace merging being undermined by partial packet traces and insufficient sniffer time synchronization;in intricate extraction of comprehensive data from the detailed traces [119]. Furthermore, as with any other sensitive data storage and transmission, there are significant concerns regarding the security of the wireless body area network [124]. The security and privacy of the data are in direct competition with the practicality and usability requirements, particularly in light of the finite space and energy resources available within the implanted module [116]. Data tampering, e.g., the deliberate destruction or manipulation of data, can result in incorrect diagnosis and ineffective and/or wrong treatment of the patient [124]. The intruder can attain patient-related data by intercepting the radio transmissions between the sensor and the receiver, even when the data being transferred is encrypted [117].