**2.3 Wireless metropolitan area network (wireless MAN)**

This is a computer network (CN) that communicates and interconnects users with various computer resources in a geographic location of the size of an urban area. The term MAN is applied to the interconnection of LANs in an urban area into a single greater network which could similarly offer effective connection to a wide area network (WAN). Wireless MAN is also used in describing the interconnection of several LANs in an urban region via the use of "point-to-point connections" between them [32].

*Categories of WNs.*

#### **2.4 Wireless wide area network (wireless WAN)**

This is another form of WN. The greater size of a WAN compared to a LAN entails the modifications in technology. WNs of diverse dimensions deliver data in the form of web pages, telephone calls and streaming video. A wireless WAN often differs from wireless LAN by using mobile telecommunication cellular network (MTCN) machineries such as 2G, 3G, 4G LTE, and 5G in transferring data. Wireless WAN is sometime called mobile broadband (MBB). These machineries are existing nationally, regionally, or even globally and are provided by a wireless service provider (WSP). Wireless WAN connectivity permits a user with a CN and a wireless WAN card to surf the network, check electronic mail, or connect to a virtual private network (VPN) from somewhere within the boundaries of WNs. Several CNs could assist in the integration of wireless WAN proficiencies. A wireless WAN could also be a closed network that covers a huge geographic location. For instance, a "mesh network or MANET" with nodes on towers, trucks, planes and buildings. It could also be a "low-power, low-bit-rate (LBR) wireless WAN, (LPWAN)," proposed to carry minor packets of information between things, habitually in the form of battery-operated sensors. Since the RMSs hardly offer a physically protected connection path, the wireless WANs characteristically integrate "encryption and authentication" approaches to make them more protected. Reportedly, several early GSM encryption procedures are imperfect, and security professionals have issued cautions that MTCN, including wireless WAN, is not that secure [32].

#### **2.5 Wireless global area network (wireless GAN)**

This refers to any network that is composed of diverse interconnected CNs (WANs) and also covers an unrestricted geographical location. It is apprehensively identical with Internet, which is considered as a GAN. Unlike LANs and WANs, GANs cover a much larger geographical area. Since GANs are used for supporting MTCNs across a number of wireless LANs, one of the main challenges for any wireless GAN is in transferring of the user communications from one LAN to another. One of the utmost popular wireless GAN categories is a broadband (BB) wireless GAN. The BB wireless GAN is a worldwide satellite Internet network (SIN) that employs transferrable terminals for telephony. The terminals connect CNs located in LAN to BB Internet.

#### **3. The IEEE 802.15.4 technology**

The "IEEE 802.15.4 wireless technology" is a "short-range communication system" which is planned to offer applications with comfortable throughput and potential necessities in Wireless PAN [4]. The main features of the "IEEE 802.15.4 wireless technology" as reported by Buratti et al. [4] are; inexpensive, truncated complexity, low consumption of power, truncated transmission data rate, to be maintained by inexpensive either fixed or moving means. One of the foremost fields of applications of this technology is the implementation and execution of WSNs.

The "IEEE 802.15.4 Working Group (the IEEE 802.15.4 Working Group) as noted by Buratti et al. [4], emphases on the standardization of the lowest two layers of the "ISO/OSI protocol stack" [33]. There are two possibilities for the higher layers characterisation, viz.; Zigbee protocols, specified by "the industrial consortia ZigBee Alliance (the industrial consortia ZigBee Alliance) and 6LowPAN. Some technical specifics interrelated to the "physical and MAC layers" as well-defined in the standard

**29**

**Figure 2.**

*ZigBee procedure stack.*

*Wireless Sensor Networks: Applications and Challenges DOI: http://dx.doi.org/10.5772/intechopen.93660*

specific consideration to the former [35].

illustrated in **Figure 2**.

**3.1 The physical layer of the IEEE 802.15.4**

frequency bands. The organisation is as follows:

extent is roughly 1000 m

transmission extent of 220 m.

1000 m;

are would be briefly discussed [34]. Also, some physiognomies interrelated to

advanced layers would be presented, bearing in mind the "Zigbee and 6LowPan," with

Buratti et al. [4] in their study reported that "the IEEE 802.15.4" main system comprises of a "radio frequency (RF) transceiver and the procedure stack," as

According to Buratti et al. [4], the "802.15.4 physical layer" functions basically in three diverse unrestricted/unlicensed bands (as well as with the diverse modalities) in respect to the geographical location where the system is positioned or installed. Nevertheless, spread spectrum procedures are somewhere required for the reduction of the interference extent/range in shared unrestricted/unlicensed. The "IEEE 802.15.4" requires a total of "27 half-duplex channels" transversely on the three

• **The 868 MHz band:** This is just a channel with data rate availability of 20 kbps, with −92 dBm RF sensitivity essential and superlative (ideal) transmission

• **The 915 MHz band:** This has ten channels with rate availability of 40 kbps; the receiver sensitivity and the superlative transmission extent are also roughly

• **The 2.4 GHz ISM band:** This has sixteen channels with data rate availability of 250 kbps, with minimum −85 dBm RF sensitivity essential and superlative

The superlative transmission extent is calculated bearing in mind that, even though any legitimately suitable power is allowed, the "IEEE 802.15.4-compliant devices" ought to be capable of communicating and transmitting at −3 dBm. Giving, the energy efficiency challenges, short rate and short duty cycle are given. The "IEEE *Wireless Sensor Networks - Design, Deployment and Applications*

This is another form of WN. The greater size of a WAN compared to a LAN entails the modifications in technology. WNs of diverse dimensions deliver data in the form of web pages, telephone calls and streaming video. A wireless WAN often differs from wireless LAN by using mobile telecommunication cellular network (MTCN) machineries such as 2G, 3G, 4G LTE, and 5G in transferring data. Wireless WAN is sometime called mobile broadband (MBB). These machineries are existing nationally, regionally, or even globally and are provided by a wireless service provider (WSP). Wireless WAN connectivity permits a user with a CN and a wireless WAN card to surf the network, check electronic mail, or connect to a virtual private network (VPN) from somewhere within the boundaries of WNs. Several CNs could assist in the integration of wireless WAN proficiencies. A wireless WAN could also be a closed network that covers a huge geographic location. For instance, a "mesh network or MANET" with nodes on towers, trucks, planes and buildings. It could also be a "low-power, low-bit-rate (LBR) wireless WAN, (LPWAN)," proposed to carry minor packets of information between things, habitually in the form of battery-operated sensors. Since the RMSs hardly offer a physically protected connection path, the wireless WANs characteristically integrate "encryption and authentication" approaches to make them more protected. Reportedly, several early GSM encryption procedures are imperfect, and security professionals have issued

cautions that MTCN, including wireless WAN, is not that secure [32].

This refers to any network that is composed of diverse interconnected CNs (WANs) and also covers an unrestricted geographical location. It is apprehensively identical with Internet, which is considered as a GAN. Unlike LANs and WANs, GANs cover a much larger geographical area. Since GANs are used for supporting MTCNs across a number of wireless LANs, one of the main challenges for any wireless GAN is in transferring of the user communications from one LAN to another. One of the utmost popular wireless GAN categories is a broadband (BB) wireless GAN. The BB wireless GAN is a worldwide satellite Internet network (SIN) that employs transferrable terminals for telephony. The terminals connect CNs located

The "IEEE 802.15.4 wireless technology" is a "short-range communication system" which is planned to offer applications with comfortable throughput and potential necessities in Wireless PAN [4]. The main features of the "IEEE 802.15.4 wireless technology" as reported by Buratti et al. [4] are; inexpensive, truncated complexity, low consumption of power, truncated transmission data rate, to be maintained by inexpensive either fixed or moving means. One of the foremost fields of applications of this technology is the implementation and execution of WSNs. The "IEEE 802.15.4 Working Group (the IEEE 802.15.4 Working Group) as noted

by Buratti et al. [4], emphases on the standardization of the lowest two layers of the "ISO/OSI protocol stack" [33]. There are two possibilities for the higher layers characterisation, viz.; Zigbee protocols, specified by "the industrial consortia ZigBee Alliance (the industrial consortia ZigBee Alliance) and 6LowPAN. Some technical specifics interrelated to the "physical and MAC layers" as well-defined in the standard

**2.5 Wireless global area network (wireless GAN)**

in LAN to BB Internet.

**3. The IEEE 802.15.4 technology**

**2.4 Wireless wide area network (wireless WAN)**

**28**

are would be briefly discussed [34]. Also, some physiognomies interrelated to advanced layers would be presented, bearing in mind the "Zigbee and 6LowPan," with specific consideration to the former [35].
