Wireless Networks - Methods to Tackle and Mitigate RF Multipath - Assignment Example

Running Header: Wireless Networks Student’s Name: Instructor’s Name: Course Code & Name: Date of Submission: (Q1)Discuss the methods to tackle and mitigate RF multipath that impact to WLAN throughput. RF interference is caused by devices such as cordless phones that host the 2.4GHz band and devices like cordless cameras that seek to disrupt the 802.11 operation. There are several ways to reduce the impact of the interference to WLAN throughput. One of the ways is quick guide hopping method that is intended to stand interference of the execution strategies of NICs (Network Interface Cards). The technique show that disjointing of the recipient and interfering by 5MHz lowers the impact of the interfering significantly, where some varying software methods like altering packet sizes, Clear Channel Assessment thresholds, rates, modulations and Forward Error Correction are unproductive. The main aim is that a particular radio connected to survive radio frequency interference from the attackers compared to radio sources, e.g. commodity NICs. Hopping is much successful than anticipated. E.g. the 3 interferences happening to channels of orthogonal would not slow down a line hoping connection (Kodialam, & Nandagopal, 2009). The reason is that hopping neighboring channels gives us a shield of security. The channel settle duration is recorded using milliseconds. It helps to avoid rapid duration measurement constraint that provide robustness and make it difficult the soaring rate of execution alongside interferences that may perhaps overpower fixed channels. Practically, many of the commodity network interface cards used currently give the capability to modify channels at moderate rate using the software platform. The other way to mitigate the impact of RF is in designing and implementation. The design uses two principles. At first is that it has to be effectual and survive nasty interferences. This dictates that it have to balance device dwelling time. During this period it will be able to aggressively make use of a channel before is revealed by interference. Secondly is that we ought to be capable of implementing it on the commodity network interface cards without altering their media access control. The hopping plan makes us to exercise dwelling period of 10 milliseconds. In the execution, a 10 millisecond dwell period is sufficient to give us a practically low of 2.5% operating cost during hopping. It can also be possible to result to similar radios to use up a portion of the dwelling period searching for the eleven channels and identifying which is being used. For the design to guarantee protection from the attacker, simply the lawful consumer be supposed to know how the hopping of the progression works. It is accomplished by means of an hash sequence to come to a decision about the next control in the progression. The implementation issue is minimized by avoiding worldwide synchronization and any alterations to 802.11 power communication behaviors that may not be well-matched. Q2) Describe the purposes of POE in WLAN design. Provide at least 3 scenarios of POE being used as the prime element in WLAN design to address the projects cost and management objectives. Power over Ethernet is passing of electrical cable along with data on Ethernet cabling. It is the use of Ethernet cables that transfer information to transmit power from the hub to the powered devices thus getting rid extra wires. The main purpose of the power over Ethernet is that the topology is very effective and little cost. Considering level of power, the fly back converter is normal option. It is not the simplest and the cheapest of the isolated topologies but also suitable to generation of many outputs. The greatest efficiency can be attained from the constant approach wherever the given productivity is smaller. The fly back converter is affected by the high electrical energy spikes throughout its power devices because of the power kept in the energy transformers’ outflow inductance (Zahedi, & Pahlavan, 2010). Maximum power over ethernet input electrical energy is fifty seven Voltages, there is no security isolation is required in the transformer and its outflow inductance it is possible to be kept very low. This leads to improved performance and reduction of electrical energy spikes so much that all electrical energy clamps be able to regularly be removed entirely from the power over Ethernet converter. There are different scenarios of POE being used. The first scenario is a single building scenario. It describes a five story building with total floor space of 50,000 square feet network connections which are provided to 120 cubicles, 15 offices, 8 other locations and 1 wireless access point on each floor. The assumption is made that other locations are to be for network printers and reception desks. This scenario provides a data port and voice port to each cubicle and office. Cubicles share the Work Group Terminal (WGT) used by the Passive Optical LAN (POL) solution while others do not. The second scenario is multiple- building scenario which consists of a campus with eight buildings and a separate data center 400 feet from each of the eight buildings. Each building has seven 25,000 square feet floors with the same distribution of cubicles, offices and other locations on each floor. There are five wireless access ports on each floor. The mix of the end-user port is identical. Each building has a main equipment room where cables are connected to the outside plant cables to the outside plant cables that connect the building to the data center. Scenario c take an example of company X which has the following; The wiring cabinet can hold 325 workers, has three switches that are stand-mounted, every switch has 3 48 cards of port and 1 24 card of port slotted in, which in it utilizes backup power over Ethernet from the switch. Q3) Describe at least 3 types of spread spectrum technology that evolve the speed and throughput for WLAN crunch wireless applications. There are different WLAN technologies that are used in the current digital age. Different types of technologies in networking wireless have become complex with time and many WLAN have come up which include direct sequence spectrum and narrowband. The first spectrum is narrow band and if we go by the name, narrow band normally use a precise radio frequency (range between 50 cps to few Kbps) for transmission of information. The other is the spread spectrum. It was earlier made for military use. The spread spectrum equipments allow for larger bandwidth by frequently changing the frequency of the signal being transmitted, making it to broaden the transmission within different frequencies. Spread spectrum makes use of larger bandwidth compared to narrowband, and the mode of the transmission is much reliable, safe and easier to distinguish. The third is the frequency hopping spread spectrum (Stallings, 2009). This spectrum uses a technology that changes the frequency by synchronization of the receiver and transmitter (by the use of a narrow band) which produces one signal during transmission. The hoping of the frequency occurs as many times as possible in a second. It changes from frequency to frequency constantly and transmission of data for a definite phase of moment in time then changing to the other frequency. Just similar to the spread spectrum, the frequency hopping spread spectrum devices take more bandwidth; this is due to the carrier in multiple frequencies. The fourth spectrum is the direct sequence. The transmitted data stream is broken down into tiny pieces through the channel. An unneeded bit prototype also is generated to any transmitted bit. Basically if the bits are long then there is a higher probability the inventive data is received properly. Direct sequence spread spectrum utilizes much of the bandwidth than the frequency hopping spectrum but direct sequence spread spectrum is dependable and interference resistance. For the reason of the chipping code, information will still be recoverable without being transmitted again to the original signal even if the bits of data are damaged. For example U.K nanotechnology networking wireless products make use direct sequence spread spectrum technology. Finally other technology is infrared. The Infrared systems make use much higher frequencies to transmit data. Similar to light, infrared will not pass through opaque materials and it should be directed to the sources should have direct contact. Q4) Provide a most implementable WLAN design solution for an office with 20 wireless employees, using WLAN capable laptops to access email, Internet, small accounting applications, printing service and other office requited applications and services for day-to-day activity. The implementation of WLAN for an office with 20 wireless employees using laptops to access emails, Internet, small accounting applications etc. has to consider the following for it to be successful. The laptops must have adapters for wireless for setting up a stand alone network which is independent when they are close to one another. It gives us an example of one on one for sharing data which does not require administration. The client will have entry to the materials of the other person but not server which is centralized. A point of access can be installed to widen the range of the network doubling-up the area at which the machines can exchange data. The point of access is linked to the network which is wired meaning that each person will gain access to the server. In our case 20 employees will only require a single point of access. Point of access is normally accomplished through surveying the site. The main aim is to cover the area of coverage with overlapping cells to enable the persons to shift effortlessly amongst group of point of access which is known as roving. During designing and implementation directional antenna is considered. Let us suppose in our case we have a wireless local area network in floor M and we want to enlarge it to hired building N, half kilometer away. One resolution should be to put an antenna which is directional facing one another. On M the antenna is linked to our network which is wired through point of access. The antenna N is linked to a point of access in that building which enable the wireless local area network connectivity in that building. Throughput in wireless local area network is product and depends on the set up. There are several reasons that affect output which may include the how many users, types of wireless LAN used, propagation factors such as multipath and the latency and bottle necks on the portions which are wired of the local area network. Wireless local area network provide throughput enough for the common local area network- applications such as access to printers which are shared and internet accessibility ( Haykin, & Moher, 2009). Technology which is wireless was developed from military for applications so security is well catered for well designed for cordless devices. It is very hard for unauthorized receivers for them to listen to the wireless local area network traffic. Encryption methods are used that make it hard for all but a good number complex to gain unofficial right of entry to network transfer of data. The cost of wireless local area network during completion may include the infrastructure expenses for the wireless point of access and user expenses for the adapters used for the wireless. Infrastructure expenses depend on the point of access numbers deployed and the number of point of access depends on the area to be covered. References. Kodialam, M., & Nandagopal, T., (2009). Characterizing achievable rates in multi-hop wireless networks. MobiCom: New Riders Zahedi, A., & Pahlavan, K. (2010). Natural Hidden Terminal and Throughput of a WLAN, IEEE Electronic Letters, 5(3), 38-49. Stallings, W., (2009). Wireless communication and networks, Prentice Hall Haykin, S. & Moher, M., (2009). Modern wireless communication, Prentice Hall Read More