## 4 Comparison and Discussion
### MAC Approach
Therefore, in scenarios of context-aware mobility, AIIA works well because it can transmit data to its neighbors without synchronizing between WBASNs. AIIA reallocates time slots to mitigate interference without negotiating with other WBASNs. The higher-capacity WBASNs and lower energy consumption are shown in the AIIA simulation results. However, the QoS of sensors is not considered in this algorithm, nor is the convergence time of the constructing table. In addition, there is a tradeoff between the length of the TDMA duration and the performance of the AIIA. CFT [31], which uses a TDMA-based MAC protocol framework, can be considered as the simplest scheme. CFT is considered as a non-negotiation method which uses CCA for carrier sensing and schedules the time slot if the channel is idle. Due to the carrier sensing, the performance of CFT is better than TDMA. This method reduces unnecessary transmissions and is thus energy efficient. However, end-to-end delay and QoS are not considered in CFT. In a case involving interference between vital medical signals, retransmission may result in a long end-to-end delay. The coloring method in [32] supports high spatial reuse in WBASNs. Convergence time is fast while power consumption is low, because the coordinators transmit a beacon to indicate which sensor can transmit. When a transmission is suspended, wasted energy is low. Despite these advantages, RIC does not consider the mobility of WBASNs or the QoS requirement of the vital signal in the superframe. Because this algorithm colors nodes randomly, the priority of each sensor in WBASNs is not considered. The node that transmits a vital signal may not be colored and therefore may not transmit, which could cause a dangerous situation in healthcare service scenarios. The 2L-MAC scheme [33] is similar to service-based scheduling [29]. The QoS requirement is the primary factor that 2L-MAC uses to decide when to transmit a signal. The benefit of the cross-layer design is to avoid collisions at the physical layer and accessibility of the idle channel. A coordinator must scan for the idle channel then poll the channel with a back-off mechanism, which aims to prevent the polling from many hubs. Sensors switch to available channels, so the mechanism satisfies both the QoS requirement and the throughput of the WBASN. Nevertheless, the power consumption in the WBASN is high because the wake-up event at the sensor node is long. Also, the end-to-end delay is large because of the back-off mechanism. Although adaptive techniques based on the IMF [34] are quite simple, they are acceptable applications for mitigating inter-WBASN interference. The SINR value is used to set a threshold for the switching technique. The advantage of the IMF is simply that because it is based on the standard MAC superframe, it can be widely applied to existing WBASNs. Nevertheless, the IMF mechanism which does not perform the channel scanning may cause collisions at the physical layer. In addition, the priority of the signal in WBASNs is not considered. In [35], the main advantage of CBWS is that it considers interference at the node level with regard to the function of sensor nodes. In addition, the position of coordinators and sensors in WBASNs is considered for grouping sensors into a clique before reallocating them into time slots. Therefore, groups of the same type of sensors residing in the interference range can be rescheduled, resulting in a continuous communication link and reduced power consumption. Compared to RIC [32], CBWSapplies the random coloring algorithm, but on the basis of the graph setup. In RIC, the colors are assigned to WBASNs so that the function of sensor nodes is not considered. In CBWS, only active sensors will be assigned colors, which leads to low power consumption and a long network lifespan while mitigating interference. The AIM algorithm [37] combines the advantages of DRA [28] and the priority-based scheduling algorithm. The priority of each sensor node is considered for orthogonal scheduling.