Marconi Invention of Wireless Telegraphy Essay Example
Marconi Invention of Wireless Telegraphy Essay Example

Marconi Invention of Wireless Telegraphy Essay Example

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  • Pages: 9 (4493 words)
  • Published: September 12, 2017
  • Type: Case Study
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In 1895, an Italian discoverer Guglielmo Marconi was the first adult male to develop the system which transmits informations via wireless media. Marconi innovation of radio telegraphy was the cardinal foundation to our modern radio communications such as satellite transmittal, wireless and telecasting broadcast medium, mobile telephone which wholly transform the manner we communicate. Wireless mesh web can be defined as a type of web that transmits informations, voice and picture traffic from one node to another via radio media ( wireless frequences ) .

The node in a mesh web are closely working together ( interconnected ) in order to supply infinitely connexion, alternate way and fast convergence of the web in the instance of node or nexus fails. Wireless mesh web was originally developed for military applications but for the past few old ages this engineering has been integrated into other commercial sectors such as medical and residential.

The designing of infirmary radio mesh web that integrated medical applications will significantly better the wellness attention bringing, cut down costs, increase the efficiency and effectivity of the wellness attention suppliers and do services more convenient for patients. It will besides enable clinicians to supervise patients remotely, give them seasonably wellness information, reminders and support ; in short WMN will well widen and dramatically alter the manner wellness attention staffs communicate with their patients and hospital systems. WMN for medical application is a type of web based on mesh architecture that allows wireless client devices anyplace within the scope of infirmary wireless signal to convey or have information from infirmary system or patient monitoring devices. The


web will dwell of the undermentioned constituents:

  • Wireless enabled pre-configured Pocket computing machine ( Personal computer ) :a device allow clinicians to have information and communicate with their patients, other clinicians and infirmary system.
  • Wireless detector:a device used to garner information from patient.
  • Wireless Hospital Pocket Electrocardiography ( ECG ) :a device used to have, direct and publish ECG.
  • Hospital information system and cognition base systems.
  • Last the Internetwhich will be used to link radio mesh web to the other webs.

There are many radio engineerings which can be used to implement radio mesh web for medical applications these including IEEE 802.11, IEEE 802.15.4, IEEE 802.16 and IEEE 802.20 or hybrid of more than one engineering. However, due to medical demands ideas of holding safe, low-priced, low-powered, wireless connexion and short scope medical devices together with undertaking purposes and aims ZigBee radio engineering was selected to be used.ZigBeeis the radio engineering which is based on IEEE 802.15.4 criterions.

It was developed by ZigBee confederation as an unfastened planetary criterion in order to supply low-power, low-priced radio communicating. This undertaking was selected because we want to research the engineering behind the radio mesh webs and the applications where it can be applied. I expect by making this I will derive deep apprehension of radio communicating which so will assist me when I go back to Africa to work in communications industry which is chiefly based in radio engineerings.

The range of this undertaking will be on look intoing the radio engineerings which can be used to supply medica

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application solutions and prove one selected engineering utilizing its development kits, specifically 802.15.4 - ZigBee. We will non incorporate this engineering into existent medical monitoring devices. This undertaking besides will extremely concentrated into researching of radio engineerings alternatively of developing the medical applications. Due to resources restraints we will make a web utilizing OPNET simulation together with ZigBee development kit faculties.

The attack, methodological analysis and resources used to finish this undertaking include the undermentioned

  • Gathering of information through reading books, diary, research documents, and cyberspace searching.
  • Select low cost, low power high suited radio engineering for medical applications.
  • Configure a little mesh web utilizing ZigBee development kit equipments so test assorted belongingss which are recommended for medical devices such as power ingestion, signal scope strength etc.
  • Analyse and compare the consequences obtained from proving, simulation and pull the decision.


Wireless mesh web ( WMN ) is a web that constructed by linking wireless nodes in a mesh topology  . This web is typically dwelling of two types of nodes ; wireless mesh routers and mesh clients. Wireless mesh routers are devices which forward traffic from one node to another and normally organize the anchor of the mesh web and have minimum mobility in mesh web. Wireless mesh routers are particular male monarch of routers which have more maps compared to conventional radio routers.

Example of these new maps including ability to back up multi-hop communicating in order to widen the wireless coverage ; usage of multiple wireless interfaces that support different frequences e.g. Wi-Fi and micro-cook in a individual node which so better the flexibleness when edifice mesh web ; and eventually with all of these maps the mesh router operate with much lower power. Wireless mesh clients are devices such as laptops, PDA, cell phones or any radio equipped devices that have individual radio interface.

These devices can be connected to a radio mesh router via either Ethernet overseas telegram or radio linkand are non limited to a fixed place if connected through radio nexus in order for them to pass on, but alternatively they are allowed to roll around and still be connected to the web every bit long as they are within the scope of web wireless moving ridge signals. The radio mesh web can be connected with assorted other webs e.g. cyberspace via the wireless gateway router. WMN can be used on the undermentioned usage instance scenarios including wellness and medical systems, enterprising networking, Transportation systems and Security and Surveillance systems.

This is a technique used in radio mesh web to increase country coverage, sing wireless client devices stay connected every bit long as possible and avoid intervention from next nodes . Multi-hopping is normally used when mesh router wants to direct informations to a client device, but the client device can non be reached or the connexion between two devices is non of acceptable quality. Therefore, alternatively of mesh router directing the informations direct to the client device, it sends this information to the nearest mesh router, presuming the following node is closer to the client device and has better connexion. By making this connexion quality can be

increased and cut down the power used by client devices to pass on.

Wireless mesh routers in general have to execute three cardinal maps, function client devices, receive traffic from another mesh node and eventually send oning traffic to another mesh node. If a individual wireless interface is used to function both mesh client devices and web backhauls, it can present web public presentation jobs and hinder scalability . Multiple wireless interface engineering mesh router solves this job by supplying multiple wireless interfaces which are dedicated to a individual communicating in a radio mesh web e.g. backhaul immersion traffic will hold dedicated individual interface, backhaul emersion traffic will hold another individual dedicated wireless interface and mesh client devices will hold one or two wireless interfaces which can be shared between them.

Besides if a individual wireless interface is used for both entrance and surpassing traffic so the throughput of this wireless interface is portion every bit, because the wireless interface can non convey and have informations at the same time. Another job of utilizing individual wireless interface is occurred when a wireless is conveying informations so the other device must be in a hearing manner and if this state of affairs is amplified throughout the mesh web so it may do the mesh web to get down decelerate and acquire to the point where it can no longer efficaciously back up voice or information traffic. Multiple wireless significantly increase the web capacity but on the other manus if client engagement ( peer-to-peer ) architecture is used to plan radio mesh web so the same job faced with individual wireless interface explained above are applied to the web since client devices on client mesh web are built in with a individual wireless interface.

Wireless mesh web inherently are more robust compared to traditional radio web, because WMN have the ability to car self-configurate, self-heal and self-organise, accordingly leting the web to go on working even in the instance of node failure  without trusting on alternate fixed. substructure.

Wireless mesh routers in wide speech production does non constraint on power ingestion since most of these devices in WMN will be powered via normal direct current overseas telegram. However, due to important progresss in power efficient protocols, and little wireless transceivers, some wireless client nodes now are able to work in really low power ingestion as a consequence make it possible to incorporate little 3-Volt DC battery into a wireless client devices to powered the device for up to 3 old ages. These devices are current used in a low-power, low informations rate applications e.g. in patient monitoring and control environments. WMN besides provides the highest grade of node mobility and flexibleness when rapid web population alterations and lowest power ingestion when the web expand beyond ( 30 -100 ) metres.

In the past few old ages many infirmaries have been faced with progressively higher wiring cost to stop up more devices on their web, but the progressively development of radio engineerings such as Wi-Fi, Bluetooth, ZigBee, and WiMax offers practical chance to replace these wired overseas telegrams with wireless media. However exchanging from overseas telegrams to wireless

engineerings requires careful consideration and analysis of these new radio engineerings in order to happen out if they are existent suited for wellness attention environment. As a measure in this way the IEEE-1073-Group was formed with the exclusive intent to develop guidelines for the usage of radio engineering for communicating in healthcare environments.

The medical applications such as delivering of existent clip wave form, patient monitoring normally have really low information rates, but require really rigorous high truth, little hold and latency, because any loss of informations or hold during transmittal of informations may hold life and decease deductions. There are different types of radio engineerings that can be used to make radio mesh web as mentioned above, but due to different demands imposed by different medical applications and utilize instance scenarios, no individual radio engineering will be able to back up all different medical applications.

Therefore, it is expected different radio engineerings will be used to plan radio mesh web in order to back up different medical applications. In this subdivision of the undertaking, we will seek to foreground different types of radio engineerings which are current used in medical field sphere and discuss in farther inside informations a low power, low cost ZigBee radio engineering, a engineering that will be used in our undertaking as explained above.

Wi-Fi is the first and oldest radio engineering criterion used in medical applications which was introduced in 1997. Wi-Fi engineering is based in IEEE 802.11 standard specifications. The original Wi-Fi engineering was design to run in a 2.4GHz set and covering distance up to 100ft with informations rate of 1- 2 Mbps on its initial version and 350ft outdoor and 150 indoor with informations rate of 54Mbps on its 2nd version. After extra development of Wi-Fi and demand from market new improved drawn-out versions of Wi-Fi was maintain introduced get downing with 802.11g which was released in 2003, work in a distance scope of up to 350ft outdoor and 150ft indoor with informations rate of 54Mbps ; 802.11n in 2003 was besides introduced to widen the information rate from 54Mbps to 200Mbps ; and farther more in 2004, 802.11i and 802.11s was introduce to heighten security characteristics and present mesh web capablenesss . Nowadays Wi-Fi engineering has been used about in every infirmary, to supply communicating between sections within the infirmaries and do it easy to reassign patient informations around the infirmaries.

WiMax ( Worldwide Interoperability for Microwave Access ) is a criterion based Wireless engineering that gives high throughput broadband connexions over long distances. WiMax has two versions used for a figure of applications Fixed WiMax and Mobile WiMax. Fixed WiMax support fixed and mobile entree applications e.g. can be used as option to overseas telegram and DSL to supply radio broadband to single and concern besides can be used as radio backhaul for metropolitan radio web. Mobile WiMax will supply mobility and rolling applications between WiMax towers and broaden the broadband services to mobile devices such as laptops, phones, PDA or any similar Mobile contraptions.

The engineering and standard specifications behind WiMax is defined in the IEEE 802.16 household  . WiMax is on the

rise as the hereafter of broadband communicating, supplying low-cost high velocity, long scope, and wireless public presentation as an option to wired webs. In a medical field sphere WiMax has assorted possible deployment scenarios e.g. in a big graduated table WiMax webs can be established and operated by regional wellness authorization in order to supply assorted telemedicine services between clinics, infirmaries and apothecary's shops in both fixed and nomadic environments. Besides in a little graduated table WiMax webs can be used to supply intranet for the infirmary.


Bluetooth is an unfastened radio engineering which was designed for usage of interchanging informations between fixed and nomadic devices over a short distance. It was original conceived as a low power, short scope radio engineering designed to replace overseas telegrams for complecting devices such as pressmans, keyboards, and mice and the engineering behind Bluetooth was based on 802.15.1 standard specification household . Bluetooth has much shorter scope comparison to other wireless engineerings ; the typical Bluetooth distance scope is about 10 meters, nevertheless optional high power scene can offer up to 100 meters coverage with the information rate of 1Mbps which is significantly little comparison to 802.11 engineerings.

However Bluetooth have the ability to supply true rolling capableness and signifier piconet “an ad-hoc computing machine web associating a user group of up to 8 devices” which accordingly from the scatternet “ a web which consist of more than one piconet” . With many advantages including low-power ingestion, little size, simple protocol, broad compatibility, and so on, Bluetooth can be applied to many medical applications including telemedicine system, permeant and uninterrupted patients supervising and wireless-integrated medical devices.

For illustration, in a mass casualty or catastrophe, trefoils can put bantam detectors on each patient to organize an ad hoc web utilizing Bluetooth, relaying uninterrupted critical mark informations to multiple having devices ( e.g. PDAs carried by doctors, or laptop base Stationss in ambulances ) . As another illustration for application of Bluetooth, radio EEGs ( EEG ) use Bluetooth radio interface to reassign EEG to PDAs

ZigBee – IEEE 802.15.4

ZigBee is wireless engineering that provides low cost, low powered, short scope wireless communicating. The engineering is based on IEEE 802.15.4 specifications and operates in unaccredited set all over the universe at the undermentioned wireless frequences ; 2.4GHz, and 900MHz .

The IEEE 802.15.4 criterion was engineered by the Institute of Electrical and Electronics Engineers in order to turn to the demands of low cost, low power radio solutions. This engineering will let wireless devices to intercommunicate and be powered by batteries which will last non for hours but alternatively for old ages. ZigBee was developed by the ZigBee Alliance, a non net income pool as an unfastened planetary criterion which is able to organize robust, self-healing ; secure ; multiple manner radio webs that are extremely suited for medical monitoring and control applications. Figure 1 below shows the relationship between the IEEE 802.15.4 and ZigBee.

From the diagram we see that ZigBee stack architecture consists of four beds, Physical bed and Media Access Control ( MAC ) bed defined by IEEE 802.15.4 and ZigBee beds such as Network, Security and Application

which place on top of IEEE 802.15.4 beds.

IEEE 802.15.4 Physical ( PHY ) Layer

This is a bed which provide interface to the physical transmittal medium e.g. Radio. It is used to supply two services ; PHY informations service and PHY direction service interfacing to the physical bed direction entity ( PLME ) . The PHY information service is used to pull off the physical wireless frequence transceiver and execute channel choice, energy and signal direction maps. This bed can run on one of the following unaccredited frequence sets.

  • A individual channel between 868 – 868.8 MHz in Europe.
  • 10 channels between 902 – 928MHz in North America.
  • 16 channels between 2400 – 2483.5 MHz worldwide.

The original 2003 criterion was designed to offer two physical bed options, both based on Direct Sequence Spread Spectrum ( DSSS ) technique. One option was designed to work in the 2.4GHz set with informations rate of 250kbps and the other in 868/915MHz sets with informations rate of 20 and 40kbps.The different informations rate between different sets was attributed to a usage of different transition techniques as explained in table 1 below.

The reversed 802.15.2 criterion was introduced in 2006 which specifies the betterment of informations rate in 868/915 MHz sets, conveying them up to back up 100 and 250kbps.Table 1 Frequency sets and informations rates


IEEE 802.15.4 Media Access Control ( MAC ) bed


Media Access Control ( MAC ) bed in ZigBee stack architecture is used to command entree to the wireless channel utilizing Carrier Sense Multiple Access with Collision Avoidance ( CSMA/CA ) mechanism . This bed is responsible for conveying beacon frames, synchronism and supplying dependable communications between nodes.


Network ( NWK ) Layer


Network bed in OSI theoretical account has defined as “a bed which is responsible to supply end-to-end way across the network” . The ZigBee web bed is responsible for managing web devices, and routing by raising actions in the MAC bed. The undertaking including get downing the web ( coordinator ) , adding and taking devices in a web, Assigning web reference, Configure new devices, routing messages, using security and discovering and maintaining of the paths.


Security Layer


ZigBee engineering adds in security functionality on its stack, controlled by the security bed in order to supply secure and dependable radio web. The different security engineering integrated on this security bed including Access Control List, Packet freshness timer, and 128- spot encoding based on the Advanced Encryption Standard ( AES ) .


Application ( APL ) Layer


The primary function of application bed is to specify the functionality of the nodes in a web. ZigBee application bed is dwelling of the undermentioned bomber beds ; Application Support ( APS ) bed and ZigBee Device Object ( ZDO )  . The APS bed is responsible for the undermentioned services

  • Keeping the binding tables that enable fiting two devices together based on their services and send oning messages between them.
  • Discovery the ability to find which other devices are runing in the same operating infinite.

While ZigBee Device Object is responsible for specifying the function of a device within the web ( e.g. ZigBee coordinator, router or end-device ) , Initiates

or answering to adhering petitions, and establishes unafraid connexion between web devices


ZigBee Routing


In by and large there are two types of routing protocols used in package switch web ; Distance vector routing and nexus province routing protocol. In distance vector routing protocol each node in the web publicize its routing tabular array to its next neighbors whereas in nexus province protocol every node in a web concept a map of the full connectivity of the web and shop this information to their routing tabular arraies. In both routing protocol there will be sporadically updates of the routing tabular arraies to see each routing tables contains merely valid routing information. Since these routing protocols require large memory and high power ingestions, the following routing algorithm were used as ZigBee routing protocol.

Ad hoc On Demand Distance Vector ( AODV ) Routing Algorithm

AODV is the type of routing protocol where by router within the web establishes the path to the finish merely on demand. That means path from beginning to finish will merely set up when beginning node want to direct packages to finish and the nodes which will be allowed to hive away and keep the routing entry of the path will be those participates in routing of packages from beginning to destination . The routing tabular array on each participant nodes will incorporate logical distance to the finish, and the reference of the following router in the way to the finish node. Any nodes which do non take portion in the relaying of packages will non keep any routing information or participating in any routing table exchange. Once the sending of package from beginning to destination finish so the path will be removed from the routing tabular arraies.

From the tabular array 2 above we see the Bluetooth engineering is besides based on 802.15.1 criterion but have less transmittal scope and battery life comparison to ZigBee. However, Bluetooth have high informations rate compared to ZigBee, while Wi-Fi engineering based on radio LAN criterion ( 802.11 ) and have really low battery life and high information rate compared to ZigBee and Bluetooth. The key points which can be analysed from the tabular array 2 above are as follows ;

  • These wireless criterions are built around what is called applications.
  • No individual criterion can run into the demands of all usage applications.

Therefore we can state application demands will find which of these wireless engineering will be used to make the web e.g. for our undertaking we choose ZigBee engineering since it meets the demands of low power low cost, and safe engineering which can be used for medical applications.


Example of medical applications utilizing ZigBee radio engineering


The terminal devices ( ZigBee Sensors ) are normally used for informations garnering from a human organic structure and so convey the informations to ZigBee enabled PDA which so display the information before path it to the other mesh linked ZigBee device to organize radio mesh web. The assemblage of informations will be performed in a timely interval manner assigned by patients so these informations will be stored and displayed in GUI at informations aggregation Centre

station for farther usage. This type of medical application can be deployed in infirmary environment in order to let clinicians to supervise critical marks of their patients.

Another radio medical application which is quickly turning up in measure and quality is wireless place monitoring systems for chronic and aged patients. The system was designed to rectify patient medical informations from their organic structure sporadically and continuously so convey the informations collected to cardinal informations waiter to be stored.

The information stored on the waiter can be accessed by clinicians remotely whenever required. This type of application has the following benefits to infirmaries and their materials including save a batch of clip for clinicians every bit good as patients, allow clinicians to at the same time supervise more than one patient at a clip which was practically impossible when utilizing traditional agencies of monitoring in which physician was required to hold direct contact with their patients and eventually patient are no longer required to be present at hospital hence cut down patient infirmary stay, increase patient safety and mobility and overall significantly cut down of infirmaries running cost.


Challenges of radio engineering in medical applications


The usage of radio engineerings in medical field doubtless can hold assorted advantages to the bing health care services. However these radio engineerings have the followers challenges which are required to be addressed in order to hold successfully wireless medical applications.

  • Network dependability: - dependability is one of the most of import factor in wireless infirmary country web, without dependable communicating infirmaries and clinics will non be willing to utilize these radio enabled devices and applications due to the fright of cases and other costs related to web failure. Therefore in order to supply robust, fast converged and dependable web, system interior decorators are required to plan a web with high redundancy links and nodes. Different web architectures are expected to be used depending on medical usage instance scenarios and application demands. In extra to redundancy links and nodes, Quality of Service ( QoS ) mechanism must be activated in any devices which have capableness to supply such services in a web.
  • Interoperability: - Since radio devices and applications that will be deployed in infirmaries are expected to be developed by different sellers which follow different criterions, hence insuring of these wireless medical devices and applications work together and work faithfully can be a challenge e.g. different radio medical devices working at different frequences. However the world of the affair is if sellers keep planing their devices and applications with interoperability capableness characteristics in head, they will significantly increase the diffusion of radio engineering and promote sellers competition which finally will consequences in more low-cost systems.
  • Device mobility: - Since both patients and clinicians could be nomadic when utilizing wireless medical application deployed in a infirmaries, so it is extremely recommended that when implementing these application system interior decorators must see utilizing multihop routing protocol. A protocol capable of facilitate speedy new paths find when health professionals moves from one room to another during unit of ammunitions and handovers between different entree points accordingly save terminal device power ingestion.
  • Wearability:

-To accomplish non-bothering and unassertive uninterrupted patient monitoring, wireless medical devices are required to be lightweight and little. But it has been known that the size and weight of battery powered devices are preponderantly determined by the size and the weight of the batteries itself and the capacity of these batteries is direct relative to its weight. However it is expected the important progresss in power efficient protocols and little wireless transceiver will great aid interior decorators to better these radio wearable medical devices and increases user 's degree of comfort.

The other major challenges arise when radio web is used to supply medical applications is security, privateness and the clip takes to larn how to utilize these new engineerings. As explain above most of these wireless devices will be powered by batteries. Therefore it traveling to be really hard for sellers to incorporate powerful encoding algorithms into these devices to see informations security and privateness does non acquire compromised, nevertheless since these complex security algorithms will necessitate high treating power and energy which can non be provided by many of these medical applications and devices, informations security and protection without utilizing complex security algorithms is traveling to be a large challenge for many developers of medical devices and applications. Besides as new radio engineerings for medical applications get farther implemented in many infirmaries and clinics presents, many of its users may happen it disputing to utilize these new applications and devices to the fullest. Therefore sellers are strong recommended to plan their best radio medical solutions which will non coercing the users to do unneeded attempts merely to larn how to utilize them.


Ethical issues refering radio mesh webs for medical applications


There are several figure of ethical issues originating when radio mesh webs engineerings are used to supply medical solutions and the most evidently ethical issue which arises in our undertaking is how both patient privateness and confidentiality will be preserved when utilizing these devices since some research workers have already exposed several exposures in the hallmark, informations privateness and unity mechanism defined in their criterions. The 2nd concerns is sing wireless moving ridge frequences used on these devices either they are safe or these wave frequences does lend in doing malignant neoplastic disease to people who stay near to them for long clip as already suspected in the past researches.