I. INTRODUCTION
In today’s world there is an increasing demand for wireless connectivity. But with the present technology there is an inefficient use of the available. A large part of the spectrum is underutilised as shown in Fig 1. Due to the inefficient use of spectrum by the current spectrum allocation methods there is a need for developing new methods which aids in efficient use of available spectrum.
One alternative solution to this is the use of alternate technology. Cognitive radio (CR) is an available option. Cognitive radio concept was introduced by Mitoala [2]. CR in general can be defined as the usage of licensed spectrum by an unlicensed user when the former is not using it. This is called as spectrum hole. CR uses these for transmission of data/voice [3]. CR as defined by Haykin is:
“Cognitive radio is an intelligent wireless communication system that is aware of its surrounding environment (i.e., outside world), and uses the methodology of understanding by- building to learn from the environment and adapt its internal states to statistical variations in the incoming RF stimuli by making corresponding changes in certain operating parameters (e.g., transmit-power, carrier-frequency, and modulation strategy) in real-time, with two primary objectives in mind: highly reliable communication whenever and wherever needed; efficient utilization of the radio spectrum.” [4]
To clearly understand the concept of CR systems a background on software defined radio (SDR). Traditional radio systems which is oriented around hardware limits cross functionality and physical intervention is needed for modification. This reduces the flexibility and increases the cost of implementation and operation. An alternative to this is softwar...
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...CR-BS environment.
5) PS-MS ↔ PS-BS: This link being bi-directional at all times is a connection between MS and BS which has to be done in one hop. PR-BS being the master has the function of communication coordination in its cell coverage area and also providing access to PR-MS to backbone network.
6) PS-MS ↔ CR-MS: This is needed for enabling interoperability between systems of different kind. Here CR-MS will become a part of PS by reconfiguring itself.
7) PS-MS ↔ CR-BS: This link also serves the same purpose as that between PS-MS↔CR-MS. Additionally if CR-BS has the capability of running the protocol of PS, access service to PR-MS can be provided through it.
8) PS-MS ↔ PS-MS: This link may be useful as ad-hoc network for wireless connection. This is present in PS. Here, if both the nodes are given CR capability, this link will mirror that of between CR-MS↔CR-MS.
a. Systems: Personnel Readiness Management (PRM), Personnel Information Management (PIM), Personnel Accounting and Strength Reporting (PASR), Unit Manning Roster (UMR), Electronic Military Personnel Office (eMILPO), Defense Theater Accounting System (DTAS), Interactive Personnel Electronic Records Management System (iPERMS).
8) Ian F. Akyildiz, Ismail H. Kasimoglu, “Ad Hoc Networks’’, Wireless sensor and actor networks: Research Challenges, Georgia Institute of Technology, USA, May-2004.
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Simultaneous communication, also known as Sim-com is a form of communication process that utilizes both signs and sound. Quite often Sim-com has been referred to as a sign supported speech; these signs are usually in English in order to ensure that there is fluency in the language. In this, it is noted that some other non-verbal cues like the use of finger spelling and visual aids which rhyme to the spoken language can be used. Simultaneous communication has always been known to be a form of communication that is intended to help people who have hearing problems (deaf) understand what is being said. In this, it is realized that over the years, Sim-com has been able to utilize other systems of communication like seeing essential English. Sim-com has proven its advantageous use in both the deaf and hearing people because it presents both the spoken language and also the non-verbal. Simultaneous language is not only used by the deaf, but also used when communicating with students at the preschool level. This is important because these children tend not to understand verbal communication fully (Beginnings, 2014).
The uses of Digital Signal Processing in communications has become so large scale that nearly any form of analog communication is considered obsolete. Today, nearly any form of communication used, aside from verbal communication, relates to Digital Signal Processing. Some of the more prominent uses for DSP in communications are; local area networks, cell pho...
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Terminal Operating Systems often utilize other technologies such as internet, EDI processing, mobile computers, wireless LANs and Radio-frequency identification (RFID) to efficiently monitor the flow of products in, out and around the terminal. Data is either a batch synchronization with, or a real-time wireless transmission to a central database. The database can then provide useful reports about the status of goods, locations and machines in the terminal. The objective of a Terminal Operating System is to provide a set of computerized procedures to manage cargo, machines and people within the facility to enable a seamless link to efficiently and effectively manage the facility. Terminal operating systems can be stand-alone systems, managed as a service or
As wireless communication and multimedia applications are increasing at a rapid pace and there is need to meet the requirements a better standard for communication is developed titled LTE. With the release of various versions over the years shows a continuous enhancement in the framework standard. This paper discusses about the advent of LTE into the mobile and wireless communication universer and the need for it. The various features and technical aspects are also discussed. With features such as closed subscriber group, self-organising networks, location services, enhancement cell ID and Multimedia Broadcast services this is a standard which pretty much became the norm. Technologies such as Orthogonal Frequency Division Multiplexing (OFDM) and Multiple-Input Multiple-Output(MIMO) which were instrumental in the evolution to the LTE-Advanced are also discussed.
When I drive my car around town running errands and going from place to place, it’s nice to listen to the radio. Now since this distance I am traveling seems to be within a 30-40 mile radius, flipping through the stations is not much of a problem for me. Now on the other hand, I do travel out of town frequently, and I hate it when I want to listen to the radio and there is no signal. The reason why none of us can is because radio signals don’t carry much farther than the town’s radius. Trying to find a station in the static is very annoying. Most of the time (especially in Iowa it seems) there are no stations for miles. Now who would honestly like to travel like that? Not me that is for sure. There is an alternative though. It’s not very expensive to get either. Satellite radio is the key to traveling without boredom. Satellite radio’s signals are cast from over 22,000 miles away from the earth’s surface. There is no static interference either!
During the increase in popularity of radio, Arthur Edwin Kennelly said (1926) "through radio I look forward to a United States of the World. Radio is standardizing the peoples of the Earth, English will become the universal language because it is predominantly the language of the ether. The most important aspect of radio is its sociological influence." Kennelly was foreseeing the potential power and impact that radio would soon come to have. By the late twenties, we would see radio become quite the sensation in the household, and this sensation would continue to prosper even through the Great Depression with aid of soap operas and popular programs such as the Lone Ranger. Radio would see a decrease in popularity during the rise of the television. Eventually, radio would find itself a niche in the media market, allowing it to continue to prosper. This would be due to the help of Frequency Modulation radio broadcasting and localization. Radio stations were now able to offer more local content than radio, touching on local news, weather, and advertisements for local businesses all at a higher sound quality. That joined with a symbiotic relationship with the recording industry and the start of formatted radio programs, the two industries were set to last for almost another fifty years (Adams, n.d.).
main advantage of FM broadcasting is of it is static free. But the drawback to