## 4 Routing Protocols for HCWSNs  
In the literature, only a few routing protocols have been defined for HCWSNs. In this section, we describe the routing protocols designed and employed in MASN, CodeBlue, and MEDiSN. _RMCP_[20]: As part of the MASN platform, [PERSON] _et al._ also proposed a reliable cluster-based communication scheme which is termed Reliable MASN Communication Protocol (RMCP) [20]. RMCP groups wireless sensor nodes into clusters to detect signals for the goal of prolonging the MASN lifetime, load balancing, and scalability. The authors state that RMCP differs from other cluster-based protocols that appear in the literature (e.g., LEACH [27] and HEED [28]), because it takes into consideration the energy level determination of sensor nodes, event-triggered and energy-aware cluster formation, and dynamic adaptation of reliability based on the cluster member density and event proximity. RMCP is a cluster based, energy-aware ECG collection scheme where the ECG data are reliably relayed to a sink node in the form of aggregated data packets. However, unlike many sensor network applications, health care monitoring can only make use of traditional in-network aggregation techniques in certain scenarios, for the collection of a specific type of data. In [20], the authors suggested that ECG data can be appropriately aggregated without compromising the integrity and privacy of the data. The simulation results show that the clustering technique used by RMCP can enable high enough throughput for the good observation of a patient's health condition. Furthermore, in the scenario where 150 sensors are in the network, MASN can maintain a PDR greater than 80%, making its deployment possibly suitable for a large nursing home. In terms of supporting the mobility pattern and speed of patients and doctors/nurses who move around in a health care environment, MASN is far from ideal as a real-time monitoring system due to excessive wireless transmission delay. For example, when the speed of a node is set to 3.6 kilometers per hour, the end-to-end delay exceeds 5 s [20]. The authors have not offered a solution to address this issue. Furthermore, the simulation results have shown increased reduction in reliability as the source data rate, number of nodes, and mobility are increased, without even considering any effects of interference or fading. In a real life deployment, the performance offered by MASN would be deemed unsuitable. _TinyADMR_[29]: The developers of CodeBlue use the TinyADMR routing protocol to meet their defined requirements of delivering data reliably and efficiently to multiple receivers. In the route discovery phase of TinyADMR, each node builds a node table that contains an entry for the publisher ID, previous hop node, and estimated cost for the best path from the publisher to the subscriber. To keep the entries in the node table updated, each publisher periodically floods a broadcast ADMR message that is propagated along all intermediate nodes. Each intermediate node that receives the ADMR message first consults its node table. If the estimated path cost from the publisher to the current node is lower than the node table entry, the new previous hop and path cost fields are updated accordingly. The path costs are estimated based on an empirical model that maps the mote's CC2420 radio's Link Quality Indicator (LQI) to an estimated link delivery ratio (LDR). For a particular path composed of several links, the PDR is computed as the product of each link's LDR. The PDR is carried in the header of each ADMR message and updated at each subsequent hop. When a subscriber wishes to receive data from a certain publisher, it sends a _route reply_ message along the reverse path from itself to the publishing devices, using the previous hop information in the node table. An intermediate node receiving the route reply message is assigned as a forwarding node and subsequently rebroadcasts it to its neighbors. Theperformance evaluation of CodeBlue aimed at exploring the effect of increased data rates on achieved throughput.