Enterprise networking and tracking system

Cellular-based tracking system is ideal for businesses which is a cheaper, more efficient. Cellular-based tracking is a useful safety feature to help the operator trace the employees who may be driving a vehicle. The main advantage of this type of tracking system is low cost as compared to the other two forms of system. Locations are reported approximately every five to ten minutes. It even tracks while the driver is making a call so it's a non-intrusive way of checking on their location at any time.

The taxi owners want to make the tracking costs as simple as possible. Cellular-based tracking system can cost per vehicle per day around $ 16. Qualified services may achieve a precision of down to 50 meters in urban areas where mobile traffic and density of antenna towers is sufficiently high. Therefore this system will not be able to record any information if the vehicle is in a low or on network area of service provider.

Wireless-passive tracking

Wireless-passive tracking systems differ from cellular-based tracking systems in the way that it is a one-time payment. But the system setup is a bit expensive with the hardware and software installation. Modern passive systems are installing wireless modems to these devices to view the tracking information even without the memory card from the GPS system in the vehicle. This addition means that wireless-passive systems is also far more detailed such as vehicle's speed, stops made.

The system can cost $25 each vehicle per day. The systems don't need to pay monthly fees for the information provided by the GPS carrier. The controllers can only be retrieved the information after the vehicle returns to the taxi company. So it's not any help if the vehicle is stolen or involved in accident.

Real-time Satellite-based tracking

Satellite-based real-time tracking use satellite GPS technology to track vehicles that leads to the collection of vehicle and GPS data. It can accurately predict arrival times. The main advantage of this GPS vehicle tracking system is that works nation-wide so the controllers can track the details of your vehicle anywhere in the country. To use this system, the controllers must have a satellite navigation system to monitor their vehicles, computer links to this satellite navigation system.

This can be an expensive system to employ and can cost around $40 each vehicle per day depending on the details of information provided by the company. The satellite-based tracking system will report anywhere as it does not rely on cellular towers but rather on a communication satellite. However, the system does not give detailed information of other two systems such as vehicle's location, direction or speed.

Although vehicle tracking system is different, all of the tracking method is based on GPS. So the fundamental operation of GPS can be same. GPS can therefore be a useful feature for Controllers who need to be able to keep track of their vehicle movements.

b) The accuracy of the tracking method

GPS will not fail no matter how harsh the signal conditions, unmatched reliability, accuracy and ease of integration. GPS can support even in areas with no GPS signals, to be exact streets with high-rise buildings, tunnels and parking lots. Likewise the drivers will never be out of contact, even on airport runs or other long-distance trips. For taxi companies, drivers cannot log-on to the system outside their working hours. The Controllers can track in real-time where their taxi is from their workstation. Controllers can monitor the driver's work force every minute, any time, day or night to improve business efficiency. It can find correction directions to reach the time sensitive destinations.

c) The information delivered by the tracking system

     The Controllers deliver information to drivers such as job details and monitor which Queues have taxis ranked and which areas have work coming in. They have to send when job offer as the work is allocated to the drivers first come, first served and makes sure that every time the work is offered to nearby driver. They can warn the drivers about speed cameras and help to avoid jams.

When the driver attack or involve in an accident, a message is sent to the Control Centre for help quickly. And the driver makes phone call to announce its arrival.

e) The method of data transmission from vehicle to centre.

The connection between the vehicle and the control centre is the Mobile Phone network. The device can send data as SMS text message or over the internet and switch to Satellite automatically when it is out of cellular network coverage.

g) Additional services that the system can provide.

     GPS has built-in nationwide address database which involves pubs, restaurants and commercial premises. The Controllers can go back and see where the driver was at a particular time, how fast he was driving and the route he took for a particular job.

h) Limitations of the system

     GPS technology does not work whether terrestrial hurdles come across and signals are not relayed. Taxis are held up and can't get to the pick-up in time. GPS is nationwide radio coverage.

We know time is money in the taxi trade. We need to know company budget and requirements before choosing a tracking system that best suits for our business. For taxi company, A2B Cars, cellular-based tracking is the most suitable. As this system is simple, easy to use and can be set up in minutes. It's ideal for businesses that have staff working outdoors and use the mobile phone the drivers can convenient to carry around with them all the time. Cellular-based tracking can track the current position of a mobile phone even on the move. Based on the cell phone GPS tracking signal, controllers could be used to find the driver's way to a location and this information provide the taxi service to direct the nearest taxi to pick up the new passenger

Needless to say, this will save the taxi company a lot of fuel money and driving time. And use of GPS tracking systems has many reasons. Using the system automatic mileage reduces downtime and enhances vehicle resale values by encouraging schedules; reduce vehicle costs by targeting speeding employees. GPS can work for 24 hours in any type of weather conditions. So the cellular-based tracking system can take advantage of increase productivity, reduce costs, improve customer service, ensure driver safety and ultimately be used to the benefit of owner, controller, driver and customer.

Task 2

Two-way voice communications system is the type of communication system set up by a company which needs to keep in contact with employees working away from base or head offices. Today the main users are public safety and security organizations including police, fire and airports and industrial users who need a reliable means of communicating with personal or groups of personnel on the move such as for taxi. There have many methods for two-way voice communications that are currently in use. They are Public Trunked Mobile Radio (PTMR), Private Mobile Radio (PMR) and etc.

Public Trunked Mobile Radio (PTMR) is a service that is an easy to use two-way radio communication, mainly used for people communicates with each other, even if some or all of them are on the move. Like other mobile networks, PTMR was originally designed for voice communications but it can support data. PTMR is mainly used for vehicle fleet communication.

Private Mobile Radio (PMR) is ideal for organizations with mobile workforce who realize the need for reliable, easy to use, communication systems. A PMR service is provided by a company for the private use of its own staff, although system management can be outsourced. PMR networks are used in truck fleet as there instant and secure voice communication between a fleet Control Center and vehicles in their fleet.

(a) How each method works (frequencies, full/half duplex, etc).

PTMR

PTMR provides mobile radio trunking services within their service area of operation. One radio channel is used exclusively by all the mobile terminals of a specific user group. PTMR eliminates the need to monitor channel before transmitting. A mobile station give permission to transmit any frequency assigned to the associated base station. PTMR share a pool of frequencies freed when the redundant 405-line TV bands were cleared.

PTMR enables voice and data communication over a half-duplex channel with a central site, typically between mobile users in an area geographically restricted owing to the transmitter power of the base station. We can either send or receive at any given instant, but we can't do both. Therefore communication can take place only in one direction at any moment in time.

PMR

PMR first started the systems simply consisted of a single base station with a number of mobiles that could communicate with this single base station. In this way a single base station with a number of different channels can be run by one operator for a number of different users and this makes efficient use of the base station equipment. A base station is a mains powered two-way radio connected to a fixed antenna.

There are PMR bands available for use by private companies around 80MHz, 160MHz and 440MHz. PMR is part of the land mobile service based on the use of half-duplex at the terminal level in order to provide closed user group communications. Communications are half-duplex so this requires strict operating procedures to control conversation. Most PMR systems have integrated features such as GPS-based vehicle tracking devices, which allow companies to monitor vehicle's location constantly.

(b) Details of the legal requirements for operating the system in your country (e.g. allocation of frequencies, licensing requirements, etc).

PTMR

A channel is allocated to the user by the system only when required, and then immediately withdrawn after use. So this can improve the quality of service both for the driver and the Controllers through the optimization of frequency utilization and increased channel use. The controller allocates infrastructure channels to more efficiently meet the communication needs with drivers. Two-way systems allowed only one station to transmit at a time while others listened, since all signals were on the same radio frequency.

All business frequencies require license to determine which frequency to use and which service best suits for operation. Private companies usually applying for a license to operate special radio networks are radio-taxi companies. PTMR is eligible to obtain licenses for any number of service areas. PTMR is defined as the sharing of radio channels amongst a number of different user groups on the same system without over hearing or interfering with each other's conversations.

PMR

All professional use of two-way radio requires a license. A licensee will only need to hold a single license for a group of radio stations processed and operated. Licenses are allocated for operation on a particular channel or channels. The driver can use of these channels to contact the mobile stations in their taxi. In this way a single base station with a number of different channels can be run by one controller for a number of drivers and this makes efficient use of the base station equipment. All the PMR equipment operates on specially allocated bands in the VHF and UHF spectrum.

(c) Costs of setting up and operating the system, including licensing costs, equipment cost, etc.

PTMR

For the users their own licenses they must pay for the license and the cost of purchase and maintenance of that equipment. The fee for the use of spectrum/procession of wireless telegraphy equipment depends upon various factors such as frequency and link length, area of operation etc.

The equipment contains like mobile walkies installed in vehicles and base station equipment for the Controllers. The cost for equipment can be $ 110. The licensing costs can be approximately $200 per month. These networks are of most benefit to those who do not need to access public fixed telephone or data networks or to incur the associated costs.

PMR

License fees are paid for a license for usage of radio communication. For the PMR system this would be the cost of initial installation plus a regular maintenance cost. The system for setting the fee is in most countries a cost recovery system, in a few others the fee setting system is based on the frequency use; the higher the bandwidth required the higher the fees.

With regard to PMR (taxi systems) the costs of the licenses in relation to the equipment costs are calculated for small and big systems. The equipment used on the PMR bands includes mobile sets used in vehicles and base station equipment installed at central locations to communicate with mobile and hand-portable sets. PMR licensing can cost approximately $ 260 per month. Equipment for a taxi company, A2B Cars, can cost approximately $ 500.

(d) Limitations of each method (interference, range, etc).

PTMR

In all eases restrictions will be placed up on the frequencies used, power levels and antenna heights in order to accommodate as many users as possible within the restricted radio spectrum available. PTMR can offer coverage up to 60 kilometers. All communications on PTMR make prone to a time limit of one minute's duration. PTMR can be assigned to 30 frequency channels for analogue and digital system.

PMR

The limitations of a PBR system are the range and area of coverage they can provide and their weaknesses in communication outside world. The range afforded by the system is very much dependant upon the base station antenna height and the local coverage. The antenna may be mounted on a high tower; coverage may extend up to distances 50 kilometers.

Base stations must be located sufficiently far apart so that interference is not experienced. Although this is perfectly acceptable in some areas it is also very evident that a lot of taxi and private hire businesses have operational areas that are not 100% covered by anyone cellular operator.

For a taxi company, A2B Cars, We should choose two-way voice communication which eliminate wasted the driver time and raise revenues for the driver and the company. So Public Trunked Mobile Radio (PTMR) is the most suitable. PTMR is the type of mobile communication system fulfills the need for communication between mobile vehicles of specialized. It is cost effective mobile communication among members of the user group. It can increase availability because of allocation of channels according to need and improve in quality of service in voice and data transmission.

The drivers can get the facility of wide area roaming in cities where the controllers have its presence with telephone interconnect. Next, the drivers can send data as PTMR radio sets have a data port, RS-232. Most definitely, it can save any company money, support higher range and secure communication. Therefore we can increase quality of service and reduce infrastructure and operating cost by using PTMR.

Task 3

The common network topology for the whole network configurations are bus, star, ring, and mesh topology. In the bus topology, all nodes are connected via a backbone that many vehicles can share to ensure that minimum spacing is maintained between them. But the entire network can close down when a single cable breaks.

Ring topologies offer very high quality data transfer rates. Each node checks the information on the LAN as it passes by. If any part of ring gets broken, the network will continue to operate. Its access method is token passing.

Star topology is the most usual type used in telecommunication network, both for telephone and computer with using the modem. In the star topology, all the nodes are connected in branches that eventually lead back to a central device. If one computer or cable fails, it can't take down the entire network. On the other hand, the whole network will not be available if central device fails. When sending signals, all computer check destination address but only computer to which the data is addressed process the data.

Connecting each device in a network to every other device builds a mesh topology. This could be most expensive as more cable and hardware are essential. If a node fails, all sites remain able to communicate.

     The majority of cablings types such as the copper wire cables and fiber-optic cables that are used to transmit data between computers. The type of copper wire cable is relatively low cost. Under the heading of copper cabling, there have twisted-pair cabling and coaxial cabling. Coaxial cable is operated as the conductor that carries cable TV into our homes. This cable carries transmission of radio frequency signals travel over central conductor.

Another type of cabling, twisted-pair cabling consist of two or more pairs of insulated strands of copper twisted together to provide noise reduction. We can get two primary types of twisted-pair cabling, unshielded twisted-pair cable (UTP) and shielded twisted-pair cable (STP). Any kinds of UTP and STP cable is the most popular form of LAN cabling. UTP Local Area Network (LAN) connections are obtained through modular RJ-45 registered jacks and plugs. STP cable can support higher bandwidth over long distance than UTP cabling.

Fiber-optic cable is plastic or glass cable designed to carry voice or digital data in the form of light pulses. This type of cable can be protected from interference as any medium get. This cable offers high degree of security for data communication and it can handle much higher data transfer rates than copper conductors. But fiber-optic cable is most expensive of all cabling types.

     To create the in-house network (LAN) for use by the controllers in a taxi company, we should use star topology and 10BaseT unshielded twisted-pair cable. The reason of choosing star topology is any one computer can fail but it will not bring down the rest of the network and can withstand fault. Although the cost of star topology is same with other topology, it can be more secure, easy to use, has a high speed of data transmission. We use 10BaseT unshielded twisted-pair cable (UTP) because it is easy to install and is moderately cost than STP. Moreover, UTP cabling for bandwidth can support up to 1000Mps. Therefore, star topology and UTP cabling is suitable to use.

Task 4

Nowadays, on one side technological developments various sources on the other hand it becomes essential to develop system that can secure that information from misuse by outsiders. Due to this, we can run into a number of problems, the biggest of which are lack of security and interference. Securing vehicular communications is an essential requirement for vehicle tracking system. In particular, communication devices are being installed in more and more cars and roadside infrastructure components.

Although car communication networks assure safety against several technical interferences, they are mostly unprotected against malicious attacks System must ensure that the transmission comes from a trusted source and has not been tampered with since transmission. Due to the large number of independent network members and the presence of the human factor, it is highly possible that misconduct will arise in the Vehicular Networks.

(a) Transmission of vehicle location data

When wireless communication occurs directly between vehicles, security and scalability issues arise. Primary security concerns include assuring that transmissions are generated by a trusted source (data authenticity), that the data has not been degraded or tampered with after it was generated (data integrity). Vehicle communication applications broadcast messages about a vehicle's current location, speed. By offering real-time traffic information, collision-avoidance assistance, automatic emergency vehicular communications will help drivers to make better informed, more coordinated, and more intelligent decisions, increasing the overall safety and efficiency of the national high way system.

For example, Denial of Service (Dos) threats are present in the wireless medium and can disable communications in a network. These are often executed for no rational reason. When the Controller send information, a driver receive imperfect information about the status of traffic signals, road conditions, or the speed and location of nearby vehicles, and is forced to make operating decisions, such as when to brake or change lines, without the benefit of all available data. An incorrect transmission from an invalid or compromised unit might put at risk the safety of the vehicle and endanger others in the vicinity.

Attackers may send spurious information in the network to affect the behavior of other drivers. They can pretend to be other vehicles by using false identities. If system gathers all of these transmissions, it is plausible that every more a driver makes will be tracked by the system. Moreover, a threat actor can exploits third-party or supply chain access or technical susceptibility to intercept data.

(b) Voice communication transmission

The security of voice communication in vehicular network is crucial. Controllers and the drivers will communicate to know data likely include location coordinates, time and date, vehicle speed and a vehicle or message identification number, and job details. There is a concern that radio coverage could extend to uninvolved vehicles which could generate false or irrelevant information. Controllers are well aware that when the phones are down, the ability to accomplish work is limited. The threat to life and property when public safety officials cannot do their job because of a major disruption in their essential communications systems or when their communications are compromised

Depending on the system's features, hackers may infiltrate the system and reprogram radios, change security keys or reassign talk groups to different channels. Unsecured systems allow hackers to gain access through a variety of illicit hacking methods such as dialing phone numbers in search of modern tones to access a network and randomly guessing user passwords.

This is due to the fact that vehicular networks are open as that the radio medium is a broadcast medium and adversaries can easily witness anything that is transmitted; and open because vehicular networks are intended to use by every vehicle. Attackers may want to bring down vehicular networks or even cause an accident. Attacks include channel jamming and aggressive injection of dummy messages.

We need a method for reducing the ability of someone to tap our communications, and in the case of interference, some way to recover and resend the data for our A2B Company. The system must assure that the data are generated by a trusted source and has not been altered after it was generated. The full identity of a vehicle sending each data should be kept private. Privacy and security issues need to be handling both from the point of view of man made error and technologically advancement. As a security feature, together with the blocking of telephone numbers, data transmission with the land-based operations centre is restricted to the correct exchange of identifiable codes and password. To protect Network security, we need to protect the systems hardware, software and associated interfaces.

We also need Communication security relates to those measures taken to ensure the confidentiality and integrity of information transmitted over the airwaves. This includes the use of encryption, the management and reprogramming of encryption keys, and the safeguarding of key codes and software. As far as technology is concerned, data encryption techniques can be done some highly sensitive data like job data. All messages transmitted from the Controllers would be digitally signed using public key encryption and authenticated by the receiving vehicle. Vehicle-based units would utilize essentially the same encryption protocol as infrastructural units. We should also relied on encryption for voice communications security.

All messages need to be uniquely signed. However, the signatures will allow the signer to be tracked and eventually reveal its true identity. Most mobile network security architectures include provisions for key distribution. This is not only the case when an encrypted channel is set up; many settings require a key to be shared for authentication and data integrity reasons. For A2B Company, we must carry out these security measures to reduce and remove threats.

Task 5

A taxi company, A2B Cars is transportation services and this company provides two main services. One is when customer requires a taxi, the driver immediately driving to their destination within 15 minutes. Next, the customers make advance booking for their journey and the company accepts their booking just before one calendar month.

Task 1 is to examine vehicle tracking systems to track the company's vehicles. So, we choose Cellular-based tracking method which is one of the GPS tracking devices.

Vehicle tracking system is an electronic device installed in a vehicle to enable the owner to track the vehicle's location. This means that the operator has access to information on all of the vehicles in their location, speed, distance traveled and maintenance details. Most modern vehicle tracking systems use Global Positioning System (GPS) for accurate information on directions and locations of the vehicle. There are three distinct types of GPS vehicle tracking devices accessible on the market today. These are cellular-based tracking, wireless -passive tracking and real-time satellite-based tracking.

Cellular-based tracking system is ideal for businesses which is a cheaper, more efficient. Cellular-based tracking is a useful safety feature to help the operator trace the employees who may be driving a vehicle. The main advantage of this type of tracking system is low cost as compared to the other two forms of system. Locations are reported approximately every five to ten minutes. It even tracks while the driver is making a call so it's a non-intrusive way of checking on their location at any time.

The taxi owners want to make the tracking costs as simple as possible. Cellular-based tracking system can cost per vehicle per day around $ 16. Qualified services may achieve a precision of down to 50 meters in urban areas where mobile traffic and density of antenna towers is sufficiently high. Therefore this system will not be able to record any information if the vehicle is in a low or on network area of service provider.

Wireless-passive tracking systems differ from cellular-based tracking systems in the way that it is a one-time payment. But the system setup is a bit expensive with the hardware and software installation. Modern passive systems are installing wireless modems to these devices to view the tracking information even without the memory card from the GPS system in the vehicle. This addition means that wireless-passive systems is also far more detailed such as vehicle's speed, stops made.

The system can cost $25 each vehicle per day. The systems don't need to pay monthly fees for the information provided by the GPS carrier. The controllers can only be retrieved the information after the vehicle returns to the taxi company. So it's not any help if the vehicle is stolen or involved in accident.

Satellite-based real-time tracking use satellite GPS technology to track vehicles that leads to the collection of vehicle and GPS data. It can accurately predict arrival times. The main advantage of this GPS vehicle tracking system is that works nation-wide so the controllers can track the details of your vehicle anywhere in the country. To use this system, the controllers must have a satellite navigation system to monitor their vehicles, computer links to this satellite navigation system.

This can be an expensive system to employ and can cost around $40 each vehicle per day depending on the details of information provided by the company. The satellite-based tracking system will report anywhere as it does not rely on cellular towers but rather on a communication satellite. However, the system does not give detailed information of other two systems such as vehicle's location, direction or speed.

Although vehicle tracking system is different, all of the tracking method is based on GPS. So the fundamental operation of GPS can be same. GPS can therefore be a useful feature for Controllers who need to be able to keep track of their vehicle movements.

GPS will not fail no matter how harsh the signal conditions, unmatched reliability, accuracy and ease of integration. GPS can support even in areas with no GPS signals, to be exact streets with high-rise buildings, tunnels and parking lots. Likewise the drivers will never be out of contact, even on airport runs or other long-distance trips. For taxi companies, drivers cannot log-on to the system outside their working hours. The Controllers can track in real-time where their taxi is from their workstation. Controllers can monitor the driver's work force every minute, any time, day or night to improve business efficiency. It can find correction directions to reach the time sensitive destinations.

     The Controllers deliver information to drivers such as job details and monitor which Queues have taxis ranked and which areas have work coming in. They have to send when job offer as the work is allocated to the drivers first come, first served and makes sure that every time the work is offered to nearby driver. They can warn the drivers about speed cameras and help to avoid jams.

When the driver attack or involve in an accident, a message is sent to the Control Centre for help quickly. And the driver makes phone call to announce its arrival.

The connection between the vehicle and the control centre is the Mobile Phone network. The device can send data as SMS text message or over the internet and switch to Satellite automatically when it is out of cellular network coverage.

     GPS has built-in nationwide address database which involves pubs, restaurants and commercial premises. The Controllers can go back and see where the driver was at a particular time, how fast he was driving and the route he took for a particular job.

     GPS technology does not work whether terrestrial hurdles come across and signals are not relayed. Taxis are held up and can't get to the pick-up in time. GPS is nationwide radio coverage.

We know time is money in the taxi trade. We need to know company budget and requirements before choosing a tracking system that best suits for our business. For taxi company, A2B Cars, cellular-based tracking is the most suitable. As this system is simple, easy to use and can be set up in minutes. It's ideal for businesses that have staff working outdoors and use the mobile phone the drivers can convenient to carry around with them all the time. Cellular-based tracking can track the current position of a mobile phone even on the move. Based on the cell phone GPS tracking signal, controllers could be used to find the driver's way to a location and this information provide the taxi service to direct the nearest taxi to pick up the new passenger

Needless to say, this will save the taxi company a lot of fuel money and driving time. And use of GPS tracking systems has many reasons. Using the system automatic mileage reduces downtime and enhances vehicle resale values by encouraging schedules; reduce vehicle costs by targeting speeding employees. GPS can work for 24 hours in any type of weather conditions. So the cellular-based tracking system can take advantage of increase productivity, reduce costs, improve customer service, ensure driver safety and ultimately be used to the benefit of owner, controller, driver and customer.

Task 2 is for two-way voice communications methods between the taxi drivers and the Controllers. Public Trunked Mobile Radio (PTMR) is suitable two-way voice communications methods.

Two-way voice communications system is the type of communication system set up by a company which needs to keep in contact with employees working away from base or head offices. Today the main users are public safety and security organizations including police, fire and airports and industrial users who need a reliable means of communicating with personal or groups of personnel on the move such as for taxi. There have many methods for two-way voice communications that are currently in use. They are Public Trunked Mobile Radio (PTMR), Private Mobile Radio (PMR) and etc.

Public Trunked Mobile Radio (PTMR) is a service that is an easy to use two-way radio communication, mainly used for people communicates with each other, even if some or all of them are on the move. Like other mobile networks, PTMR was originally designed for voice communications but it can support data. PTMR is mainly used for vehicle fleet communication.

Private Mobile Radio (PMR) is ideal for organizations with mobile workforce who realize the need for reliable, easy to use, communication systems. A PMR service is provided by a company for the private use of its own staff, although system management can be outsourced. PMR networks are used in truck fleet as there instant and secure voice communication between a fleet Control Center and vehicles in their fleet.

PTMR provides mobile radio trunking services within their service area of operation. One radio channel is used exclusively by all the mobile terminals of a specific user group. PTMR eliminates the need to monitor channel before transmitting. A mobile station give permission to transmit any frequency assigned to the associated base station. PTMR share a pool of frequencies freed when the redundant 405-line TV bands were cleared.

PTMR enables voice and data communication over a half-duplex channel with a central site, typically between mobile users in an area geographically restricted owing to the transmitter power of the base station. We can either send or receive at any given instant, but we can't do both. Therefore communication can take place only in one direction at any moment in time.

PMR first started the systems simply consisted of a single base station with a number of mobiles that could communicate with this single base station. In this way a single base station with a number of different channels can be run by one operator for a number of different users and this makes efficient use of the base station equipment. A base station is a mains powered two-way radio connected to a fixed antenna.

There are PMR bands available for use by private companies around 80MHz, 160MHz and 440MHz. PMR is part of the land mobile service based on the use of half-duplex at the terminal level in order to provide closed user group communications. Communications are half-duplex so this requires strict operating procedures to control conversation. Most PMR systems have integrated features such as GPS-based vehicle tracking devices, which allow companies to monitor vehicle's location constantly.

A channel is allocated to the user by the system only when required, and then immediately withdrawn after use. So this can improve the quality of service both for the driver and the Controllers through the optimization of frequency utilization and increased channel use. The controller allocates infrastructure channels to more efficiently meet the communication needs with drivers. Two-way systems allowed only one station to transmit at a time while others listened, since all signals were on the same radio frequency.

All business frequencies require license to determine which frequency to use and which service best suits for operation. Private companies usually applying for a license to operate special radio networks are radio-taxi companies. PTMR is eligible to obtain licenses for any number of service areas. PTMR is defined as the sharing of radio channels amongst a number of different user groups on the same system without over hearing or interfering with each other's conversations.

All professional use of two-way radio requires a license. A licensee will only need to hold a single license for a group of radio stations processed and operated. Licenses are allocated for operation on a particular channel or channels. The driver can use of these channels to contact the mobile stations in their taxi. In this way a single base station with a number of different channels can be run by one controller for a number of drivers and this makes efficient use of the base station equipment. All the PMR equipment operates on specially allocated bands in the VHF and UHF spectrum.

For the users their own licenses they must pay for the license and the cost of purchase and maintenance of that equipment. The fee for the use of spectrum/procession of wireless telegraphy equipment depends upon various factors such as frequency and link length, area of operation etc.

The equipment contains like mobile walkies installed in vehicles and base station equipment for the Controllers. The cost for equipment can be $ 110. The licensing costs can be approximately $200 per month. These networks are of most benefit to those who do not need to access public fixed telephone or data networks or to incur the associated costs.

License fees are paid for a license for usage of radio communication. For the PMR system this would be the cost of initial installation plus a regular maintenance cost. The system for setting the fee is in most countries a cost recovery system, in a few others the fee setting system is based on the frequency use; the higher the bandwidth required the higher the fees.

With regard to PMR (taxi systems) the costs of the licenses in relation to the equipment costs are calculated for small and big systems. The equipment used on the PMR bands includes mobile sets used in vehicles and base station equipment installed at central locations to communicate with mobile and hand-portable sets. PMR licensing can cost approximately $ 260 per month. Equipment for a taxi company, A2B Cars, can cost approximately $ 500.

In all eases restrictions will be placed up on the frequencies used, power levels and antenna heights in order to accommodate as many users as possible within the restricted radio spectrum available. PTMR can offer coverage up to 60 kilometers. All communications on PTMR make prone to a time limit of one minute's duration. PTMR can be assigned to 30 frequency channels for analogue and digital system.

The limitations of a PBR system are the range and area of coverage they can provide and their weaknesses in communication outside world. The range afforded by the system is very much dependant upon the base station antenna height and the local coverage. The antenna may be mounted on a high tower; coverage may extend up to distances 50 kilometers.

Base stations must be located sufficiently far apart so that interference is not experienced. Although this is perfectly acceptable in some areas it is also very evident that a lot of taxi and private hire businesses have operational areas that are not 100% covered by anyone cellular operator.

For a taxi company, A2B Cars, We should choose two-way voice communication which eliminate wasted the driver time and raise revenues for the driver and the company. So Public Trunked Mobile Radio (PTMR) is the most suitable. PTMR is the type of mobile communication system fulfills the need for communication between mobile vehicles of specialized. It is cost effective mobile communication among members of the user group. It can increase availability because of allocation of channels according to need and improve in quality of service in voice and data transmission.

The drivers can get the facility of wide area roaming in cities where the controllers have its presence with telephone interconnect. Next, the drivers can send data as PTMR radio sets have a data port, RS-232. Most definitely, it can save any company money, support higher range and secure communication. Therefore we can increase quality of service and reduce infrastructure and operating cost by using PTMR.

Task 3 is to create the in-house network (LAN) for use by the Controllers. We should use star topology and 10BaseT unshielded twisted-pair cable

The common network topology for the whole network configurations are bus, star, ring, and mesh topology. In the bus topology, all nodes are connected via a backbone that many vehicles can share to ensure that minimum spacing is maintained between them. But the entire network can close down when a single cable breaks.

Ring topologies offer very high quality data transfer rates. Each node checks the information on the LAN as it passes by. If any part of ring gets broken, the network will continue to operate. Its access method is token passing.

Star topology is the most usual type used in telecommunication network, both for telephone and computer with using the modem. In the star topology, all the nodes are connected in branches that eventually lead back to a central device. If one computer or cable fails, it can't take down the entire network. On the other hand, the whole network will not be available if central device fails. When sending signals, all computer check destination address but only computer to which the data is addressed process the data.

Connecting each device in a network to every other device builds a mesh topology. This could be most expensive as more cable and hardware are essential. If a node fails, all sites remain able to communicate.

     The majority of cablings types such as the copper wire cables and fiber-optic cables that are used to transmit data between computers. The type of copper wire cable is relatively low cost. Under the heading of copper cabling, there have twisted-pair cabling and coaxial cabling. Coaxial cable is operated as the conductor that carries cable TV into our homes. This cable carries transmission of radio frequency signals travel over central conductor.

Another type of cabling, twisted-pair cabling consist of two or more pairs of insulated strands of copper twisted together to provide noise reduction. We can get two primary types of twisted-pair cabling, unshielded twisted-pair cable (UTP) and shielded twisted-pair cable (STP). Any kinds of UTP and STP cable is the most popular form of LAN cabling. UTP Local Area Network (LAN) connections are obtained through modular RJ-45 registered jacks and plugs. STP cable can support higher bandwidth over long distance than UTP cabling.

Fiber-optic cable is plastic or glass cable designed to carry voice or digital data in the form of light pulses. This type of cable can be protected from interference as any medium get. This cable offers high degree of security for data communication and it can handle much higher data transfer rates than copper conductors. But fiber-optic cable is most expensive of all cabling types.

     To create the in-house network (LAN) for use by the controllers in a taxi company, we should use star topology and 10BaseT unshielded twisted-pair cable. The reason of choosing star topology is any one computer can fail but it will not bring down the rest of the network and can withstand fault. Although the cost of star topology is same with other topology, it can be more secure, easy to use, has a high speed of data transmission. We use 10BaseT unshielded twisted-pair cable (UTP) because it is easy to install and is moderately cost than STP. Moreover, UTP cabling for bandwidth can support up to 1000Mps. Therefore, star topology and UTP cabling is suitable to use.

Task 4 is to provide security issues for our A2B company when transmission of vehicle location data and voice communications transmission. Nowadays, on one side technological developments various sources on the other hand it becomes essential to develop system that can secure that information from misuse by outsiders. Due to this, we can run into a number of problems, the biggest of which are lack of security and interference. Securing vehicular communications is an essential requirement for vehicle tracking system. In particular, communication devices are being installed in more and more cars and roadside infrastructure components.

Although car communication networks assure safety against several technical interferences, they are mostly unprotected against malicious attacks System must ensure that the transmission comes from a trusted source and has not been tampered with since transmission. Due to the large number of independent network members and the presence of the human factor, it is highly possible that misconduct will arise in the Vehicular Networks.

When wireless communication occurs directly between vehicles, security and scalability issues arise. Primary security concerns include assuring that transmissions are generated by a trusted source (data authenticity), that the data has not been degraded or tampered with after it was generated (data integrity). Vehicle communication applications broadcast messages about a vehicle's current location, speed. By offering real-time traffic information, collision-avoidance assistance, automatic emergency vehicular communications will help drivers to make better informed, more coordinated, and more intelligent decisions, increasing the overall safety and efficiency of the national high way system.

For example, Denial of Service (Dos) threats are present in the wireless medium and can disable communications in a network. These are often executed for no rational reason. When the Controller send information, a driver receive imperfect information about the status of traffic signals, road conditions, or the speed and location of nearby vehicles, and is forced to make operating decisions, such as when to brake or change lines, without the benefit of all available data. An incorrect transmission from an invalid or compromised unit might put at risk the safety of the vehicle and endanger others in the vicinity.

Attackers may send spurious information in the network to affect the behavior of other drivers. They can pretend to be other vehicles by using false identities. If system gathers all of these transmissions, it is plausible that every more a driver makes will be tracked by the system. Moreover, a threat actor can exploits third-party or supply chain access or technical susceptibility to intercept data.

The security of voice communication in vehicular network is crucial. Controllers and the drivers will communicate to know data likely include location coordinates, time and date, vehicle speed and a vehicle or message identification number, and job details. There is a concern that radio coverage could extend to uninvolved vehicles which could generate false or irrelevant information. Controllers are well aware that when the phones are down, the ability to accomplish work is limited. The threat to life and property when public safety officials cannot do their job because of a major disruption in their essential communications systems or when their communications are compromised

Depending on the system's features, hackers may infiltrate the system and reprogram radios, change security keys or reassign talk groups to different channels. Unsecured systems allow hackers to gain access through a variety of illicit hacking methods such as dialing phone numbers in search of modern tones to access a network and randomly guessing user passwords.

This is due to the fact that vehicular networks are open as that the radio medium is a broadcast medium and adversaries can easily witness anything that is transmitted; and open because vehicular networks are intended to use by every vehicle. Attackers may want to bring down vehicular networks or even cause an accident. Attacks include channel jamming and aggressive injection of dummy messages.

We need a method for reducing the ability of someone to tap our communications, and in the case of interference, some way to recover and resend the data for our A2B Company. The system must assure that the data are generated by a trusted source and has not been altered after it was generated. The full identity of a vehicle sending each data should be kept private. Privacy and security issues need to be handling both from the point of view of man made error and technologically advancement. As a security feature, together with the blocking of telephone numbers, data transmission with the land-based operations centre is restricted to the correct exchange of identifiable codes and password. To protect Network security, we need to protect the systems hardware, software and associated interfaces.

We also need Communication security relates to those measures taken to ensure the confidentiality and integrity of information transmitted over the airwaves. This includes the use of encryption, the management and reprogramming of encryption keys, and the safeguarding of key codes and software. As far as technology is concerned, data encryption techniques can be done some highly sensitive data like job data. All messages transmitted from the Controllers would be digitally signed using public key encryption and authenticated by the receiving vehicle. Vehicle-based units would utilize essentially the same encryption protocol as infrastructural units. We should also relied on encryption for voice communications security.

All messages need to be uniquely signed. However, the signatures will allow the signer to be tracked and eventually reveal its true identity. Most mobile network security architectures include provisions for key distribution. This is not only the case when an encrypted channel is set up; many settings require a key to be shared for authentication and data integrity reasons. For A2B Company, we must carry out these security measures to reduce and remove threats.

Reference

Web Reference

http://www.cse.wustl.edu/~jain/cse574-06/ftp/vehicular_wireless.pdf

http://www.springerlink.com/content/x8q6260026m8676m/

http://crypto.stanford.edu/portia/papers/Zimmer_EIT.pdf

http://www.safecomprogram.gov/NR/rdonlyres/95138DCD-D7AD-4A76-88E33022CCA79112/0/Public_Safety_Communication_Security_Awareness_Guide.pdf

http://www.ics.uci.edu/~dsm/papers/sec001.pdf

http://elle.baxpace.com/Networking/Enterprise%20Networking/Enterprise%20Networking_Vis2.pdf

http://www.thehindubusinessline.com/2003/01/08/stories/2003010800170700.htm

http://www.gpsvehicletrackingreview.com/tag/wireless-passive-tracking/

http://www.mynationlink.com/blog/?page_id=183

http://www.networktutorials.info/pages/mobile_tracking.html

http://www.themobiletracker.com/english/tracking.html

http://voicendata.ciol.com/content/vNd100/2003/103072824.asp

http://www.bmv.ohio.gov/misc/fees.htm

http://www.radiowholesale.com/

http://varma.ece.cmu.edu/Auto-CPS/Guo_Michigan.pdf

http://crypto.stanford.edu/portia/papers/Zimmer.pdf

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