Limitations Of Wireless Communication

In Fig. 1, the 4 nodes are considered. Among the four nodes 2 of the nodes (Node 1 and Node 2) are primary networks and 2 other nodes (Node A and Node B) are secondary networks. The two networks act in different frequency range. The primary network acts at a range of 2.4GHz - 2.4835GHz range. The secondary network acts at a range of 433MHz - 473MHz represents the block diagram of the proposed system. The use of different frequencies increases the number of users. Node 1 and Node 2 communicate at 2.4GHz and Node A and Node B communicate at 433.9MHz. The nodes are made mobile and this causes high interference. This is cancelled by channeling where the frequencies are slotted. Multi-hop cognitive radio technique occurs when the data is transmitted from one secondary node to another which is out of range via primary node. At that time the primary node which is of MIMO antenna switches itself to the secondary node frequency and transmits the data. Wireless MIMO systems with multiple antennas employed at both the transmitter and receiver have gained attention because of their promising improvement in terms of performance and bandwidth efficiency [8].

In the recent years, wireless technologies have taken a new dimension in the ways society lives. Wireless broadband is available to everyone. Whether the users are at home, driving the car, sitting in the park, and it would even work while people are a pleasure boat ride in the middle of a lake. And because of this, the need to have information at any time and be connected in all places, all the time has been satisfied.

The market for wireless communications has experienced incredible growth over recent years and wireless LANs have rapidly become a very

In MIMO system there is multiple antennas is provided at the transmitter side as well as receiver side. Using multiple antennas at the transmitter and the receiver side could able to increase spectral efficiency, produces higher capacity and provides more data rates for wireless communication. In MIMO system there is SU-MIMO that is called single user MIMO in which when there is data rates need to be increased for single user then it is known as SU-MIMO, and if there is individual stream is allocated to multiple users; then it is called multiuser MIMO (MU-MIMO).

The increase in the transmission speed in the IEEE 802.11n standard is achieved, firstly, due to the doubling of the channel width from 20 to 40 MHz, and secondly, due to the implementation of MIMO technology. MIMO (Multiple Input Multiple Output) technology involves the use of multiple transmit and receive antennas. (Mitchell, 2017)

The best technology system for the Naval Academy would be the 802.11a standard. It has 54 Mbps throughput capability as well as adequate range, sufficient for classroom use. Since the 54 Mbps is shared amongst all users, it would allow, at a minimum, 2 Mbps for each user in a class of 20 midshipmen operating simultaneously. It also has higher data rates at comparable distances

Multipath propagation is an essential component of all wireless communication system. Conventional radio systems rely on the strong primary signal and also make use of multipath mitigation techniques to overcome multipath propagation and interference. Beam forming technology or smart antenna technology is used for this purpose. A smart antenna is capable of routing transmitted beam by scheming the phase of the signal at each element of the antenna array to the receiver. Receiving diversity, this uses numerous antennas at the receiver side and merges all the received signals to improve the signal reliability. These techniques are used to reduce the effect of multipath propagation on the communication systems. MIMO makes use of multipath propagation to get better throughput, range and reliability [Berrou 1996].

The wireless channel is different and much more unpredictable than the wire line channel because of factors such as multipath and shadow fading, Doppler shift, and time dispersion or delay spread. These factors are all related to variability introduced by mobility of the user and the wide range of environmental conditions that are encountered as a result.

UniFi is an amalgamation of “Uni” which denotes togetherness and camaraderie, while “Fi” symbolieses fibre optics.Unifi is the triple-play servis by Telekom Malaysia. The residential package is a triple play UniFi service which is called VIP because it comes with three services which are V – Video or internet Protocol television, I – High Speed Internet and P – Phone.Unifi is a broadband service that uses fibre optics to deliver high speed internet, phone and IPTV service at home. The type of technology use to deliver UniFi service to customer’s homes would depends on the type of customer premise. If the customer’s premise is a landed property. Fibre to the Home (FTTH) will be used whereas if the customer’s is a high rise building. Very high speed Digital Subscriber Line 2 (VDSL 2) will be use.

frequency offsets in the subcarriers, the orthogonality among the subcarriers breaks and this causes intercarrier interference (ICI). The second drawback, is that

WiMAX (Worldwide Interoperability for Microwave Access) is present as a solution to the limitations of access at Wi-Fi planned for adoption in the space. The use of OFDM technology is able to provide data service to 70 Mbps in a radius of 50 km. Radius to make WiMAX broadband telecommunications network as technology replaces fixedline. Compared to the fixedline network WiMAX installation fees are much cheaper.

Many households across the United States are using internet systems. Wireless internet connections can be found in almost every home. This makes access to the net simpler than ever. Consequently, the connection is not always the most reliable. Individuals that play online video games understand wireless connections are not as dependable as a hard wired connection. These WIFI connections tend to become overwhelmed when there are multiple devices sharing the same connection. For this reason, the result will be lagging, buffering, or complete signal loss. Many manufactured devices have the compatibility of wired connection use. Smart televisions, desktop computers, video game platforms, laptop computers and smart blu ray players are some

Wi-Fi Internet access is fast gaining popularity as we are entering the 'unplugged ' phase of communication technology. This journey towards an unplugged world began with the first telegraph and first radio. Since then, telecommunication technology has not looked back and has shown its versatility by contributing to every field of technology. Wi-Fi has developed from synergy of wireless communication, computer networking and Internet technology. It has radically changed the way we connect and communicate.Wi-Fi (Wireless Fidelity) is a generic term that refers to the IEEE 802.11 communications standard for Wireless Local Area Networks (WLANs). Wi-Fi works on three modes namely Ad hoc, Infrastructure and Extended modes.Ad hoc network is P2P mode. Ad hoc does not use any intermediary device such as Access Point. Infrastructure and Extended modes use Access Point as interface between wireless clients.To create wireless networks with a range of about one hundred meters,802.11 technologyWith proper planning and selection antennas, same equipment can be used to make point-to-multipoint links and point-to-point links of several hundred meters.In this projectto enhance the coverage area of an access point to several hundred

[1]S. M. Alamouti, describes a simple two-branch transmit diversity scheme. Using two transmit antenna and one receive antenna, the new transmit antenna provides the same diversity order as maximal-ratio receiver combining (MRRC) with one transmit and two receive antennas. The scheme easily be generated to two transmit antenna and M receive antenna to provide a diversity order of 2M. This scheme does not require any bandwidth expansion any feedback from the receiver to the

In this global world of technologies where the communication is being modern day by day, on every other day the new technologies are being invented so in this vast world of growing technologies the cognitive radio network is another addition and a step toward fast and secure communication. Cognitive radio network is the network used for wireless communication which uses the spectrum of frequencies. It is an intelligent network in a sense that it can recognize the channels in use or vacant, the ability of this network is that it can shift the data on vacant channel without letting the other busy channel get disturbed. CRN is a technology which works on the spectrum of frequencies, sensing the spectrum of frequencies at receiver’s