###### Abstract

Table 1: Requirements of sensors for patient monitoring systems [1]. Figure 1: Wireless body area sensor network overview. body area networks (WBANs). ZigBee is a popular industrial standard that works above the IEEE 802.15.4 MAC layer and is widely available in the market as a ready product [1]. Various challenges have been discussed when using different methodologies and approaches [25; 26; 27; 28; 29; 30; 31; 32; 33; 34]. The QoS concerns in WBASNs are different and more challenging as the patient monitoring applications generate a large number of small packets in short time intervals; these packets require timely and reliable delivery with efficient channel access. The collected data must reach the sink (coordinator) node within a predefined threshold of delay; otherwise, it will not remain meaningful [16; 17; 18]. In WBASNs, latency must be less than 250 ms for most applications; however, it is <125 ms for some critical medical applications. Similarly, sensor nodes should be capable of reliable data transmission, and the collected information must be sent to the coordinator node with a defined probability of success because lost or missing data could affect data processing and relevant decision-making. However, there are trade-offs among reliability, delay and energy consumption. If we want higher reliability, then delay and power consumption will increase. Moreover, less delay and high reliability tend to consume more energy. Table 1 shows values of the required data rate and latency for wearable sensors for patient monitoring systems. Meanwhile, several survey papers containing various aspects of WBASNs have been published [35; 36]. In [1], the authors provided a detailed survey of WBASNs by considering the IEEE 802.15.6 standard. It covers all the aspects, including applications, standardisation efforts and physical, MAC and routing protocols. The authors discussed the state of the art of WBASNs in terms of application requirements and then linked it to the routing protocols. A detailed comparison of routing protocols is provided by considering delay, reliability, throughput and energy consumption. Further, open issues in this area are highlighted. The authors [ focused on the energy and power issues of WBASNs. Various protocols are discussed and summarised by considering power and energy consumption as key performance contributors [37; 38; 39; 40; 41; 42]. In comparison to the existing surveys in the WBASN area, the summary of contributions for this paper is presented as follows:  
* We conduct a comprehensive survey of MAC and routing protocols of WBASNs by considering the patient monitoring systems under the standards IEEE 802.15.4 and IEEE 802.5.6; in contrast, most of the published surveys of WBASNs only focused on IEEE 802.15.6. The reason for selecting IEEE 802.15.4 along with IEEE 802.15.6 is that most industrial implementations use IEEE 802.15.4 for WBASNs. The IEEE 802.15.6 standard as a ready solution is still not available. * The categorisation of MAC protocols for WBASNs is provided based on the literature from the period 2005 to 2019 for the IEEE 802.15.4 and IEEE 802.15.6 standards. Based on the provided categorisation, a comparative analysis of the MAC protocols is provided; these protocols optimise the IEEE 802.15.4 and IEEE 802.15.6 standards in terms of delay reliability, throughput, mobility, interference and energy consumption. In contrast, the published surveys of WBASNs cover one or two categorisations of MAC protocols by only considering IEEE 802.15.6, which is still not widely available, and most patient monitoring systems use IEEE 802.15.4. * We provide a categorisation of the routing protocols for WBASNs for the standards IEEE 802.15.4 and IEEE 802.15.6 from the period 2005 to 2019. Although similar categorisation can be seen in the published surveys, in the published surveys, the discussion regarding open issues and challenges for each category is missing.