Wireless Communication and types

Wireless communication is among technology’s biggest contributions to mankind. Wireless communication involves the transmission of information over a distance without help of wires, cables or any other forms of electrical conductors. The transmitted distance can be anywhere between a few meters (for example, a television’s remote control) and thousands of kilometres (for example, radio communication).

Some of the devices used for wireless communication are cordless telephones, mobiles, GPS units, wireless computer parts, and satellite television.

Advantages Representational Image Of Wireless communication

Fig. 1: Representational Image Of Wireless Communication

Wireless communication has the following advantages:

i. Communication has enhanced to convey the information quickly to the consumers.

ii. Working professionals can work and access Internet anywhere and anytime without carrying cables or wires wherever they go. This also helps to complete the work anywhere on time and improves the productivity.

iii. Doctors, workers and other professionals working in remote areas can be in touch with medical centres through wireless communication.

iv. Urgent situation can be alerted through wireless communication. The affected regions can be provided help and support with the help of these alerts through wireless communication.

v. Wireless networks are cheaper to install and maintain.

Disadvantages

The growth of wireless network has enabled us to use personal devices anywhere and anytime. This has helped mankind to improve in every field of life but this has led many threats as well.

Wireless network has led to many security threats to mankind. It is very easy for the hackers to grab the wireless signals that are spread in the air. It is very important to secure the wireless network so that the information cannot be exploited by the unauthorized users. This also increases the risk to lose information. Strong security protocols must be created to secure the wireless signals like WPA and WPA2. Another way to secure the wireless network is to have wireless intrusion prevention system.

Types of wireless communication

The different types of wireless communication technologies include:

Type1: Infrared wireless communication

i. Infrared (IR) wireless communication:

IR wireless communication communicates data or information in devices or systems through infrared (IR) radiation. Infrared is electromagnetic energy at a wavelength that is longer than that of red light.

Working:

IR wireless is used for short and medium-range communications and security control. For IR communication to work, the systems mostly operate in line-of-sight mode which means that there must be no obstruction between the transmitter (source) and receiver (destination).

Infrared is used in television remote controls and security systems.

In the electromagnetic spectrum, infrared radiation lies between microwaves and visible light, therefore, they can be used as a source of communication.

Fig. 2: Image Showing Various Devices Using IR Communication

A photo LED transmitter and a photodiode receptor are required for successful IR communication. The LED transmitter transmits the infrared signal in the form of non-visible light, which is captured and retrieved as information by the photo receptor. In this way, the information between the source and the target is transferred.

The source and/or destination can be laptops, mobile phones, televisions, security systems and any other device that supports wireless communication.

Type2: Broadcast Radio

ii. Broadcast Radio

Basically an audio broadcasting service, radio broadcasts sound through the air as radio waves. It uses a transmitter to transmit radio waves to a receiving antenna. To broadcast common programming, stations are linked to the radio networks. The broadcast occurs either in syndication or simulcast (simultaneous broadcast) or both. Radio broadcasting can also be done via cable FM, the internet and satellites. A radio broadcast sends data over long distances (across countries) at up to 2 megabits per second (AM/FM Radio).

Fig. 3: Figure showing Broadcast Radio Transmission

Working:

Radio waves are electromagnetic signals transmitted by an antenna. Radio waves have different frequency segments, and you will be able to pick up an audio signal by tuning into a specific frequency segment.

Fig. 4: An Electromagnectic Spectrum With Range Of Frequencies And Wavelengths

Let us take an example of a radio station. When the Radio Jockey says “You are listening to 93.7 FM”, what he actually means is that signals are being broadcasted at a frequency of 97.3 megahertz, which in turn means that the transmitter at the station is oscillating at a frequency of 93,700,000 cycles per second.

When you wish to listen to 93.7 FM, all you have to do is tune the radio to accept that particular frequency and you will receive flawless audio reception.

Type3: Microwave Radio

iii. Microwave Radio

Microwave transmission involves the transfer of voice and data through the atmosphere as super high-frequency radio waves called microwaves. Microwave transmission is mainly used to transmit messages between ground-based stations and satellite communications systems.

Working:

Microwave transmission mainly uses radio waves whose wavelengths are conveniently measured in small units such as centimeters. Microwaves belong to the radio spectrum ranges of roughly 1.0 gigahertz (GHz) to 30 GHz.

Antennas used in microwave transmissions are of convenient sizes and shapes. Microwave transmission depends on line-of-sight in order to work properly. For two way communications to take place, two frequencies are used. However, this does not require two antennas because the frequencies can be dealt with one antenna at both ends.

The distance covered by microwave signals relies on the height of the antenna. Each antenna is built with a fitted repeater to regenerate the signal before passing it on to the next antenna in line. The ideal distance between each antenna is approximately 25 miles.

The main drawback of microwave signals is that they can be affected by bad weather, especially rain.

Type4: Communication Satellites

iv. Communications Satellites

A communication satellite is an artificial satellite used specifically as a communication transmitter/receiver in orbit. It behaves like a radio relay station above the earth to receive, amplify, and redirect analog and digital signals carried on a specific radio frequency.

Working:

Data is passed through a satellite using a transponder which is a signal path. Most satellites have between 24 to 72 transponders, with a single transponder capable of transmitting and receiving 155 million bits of information per second. This huge capability makes communication satellites an ideal medium for transmitting and receiving all kinds of content, including audios and videos.

Fig. 5: Simple Diagram To Show Working Of A Satellite Communication

Satellites transmit information by using frequency bands known as C-band and the higher Ku-band. In the near future, the use of a much higher frequency band known as Ka-band is expected to increase.

Applications

Applications of Wireless Communication

Television Remote Control – Modern televisions use wireless remote control. Currently radio waves are also used.

Wi-Fi – This is a wireless local area network that establishes internet connection with the portable computers.

Security systems – For homes and office buildings, hard wired implementation security systems are replaced by the Wireless technology.

Cellular Telephone – Radio waves are used to facilitate the operator to make phone calls from any place on the earth. CDMA, GSM, and 3G are examples of the advancement made by wireless communication in the domain.

Wireless energy transfer – A process where a power source transmits electrical energy to electrical load which does not have built-in power source wirelessly.

Computer Interface Devices – Computer hardware manufacturers had realized that having so many wires to communicate between devices would confuse the consumer. So they switched to wireless technology to facilitate their consumers, thus making it easy to mediate between a computer and other peripherals including mouse and keyboard. Earlier, such units required bulky, highly limited transceivers but recent generations of computer peripheralsuse compact and high-quality wireless devices such as Bluetooth for communication. These days, wireless devices have become very common and are preferred for their ease of handling and reliability. In reality, wireless-enabled devices have a slightly slower response time than conventional wired devices. This issue is being addressed by manufacturers and will be taken care of in the near future. Initial concerns that had risen regarding the security of wireless keyboards have also been taken care of with the advent of technology.

History

The birth of wireless communications dates back to 1901 when M. G. Marconi successfully established a radio link between a land-based station and a tugboat. Since then, rapid strides have been made in the realm of wireless communication, enabling man to live life better in this digital age.

Initially, wireless communication was solely used in the military to fulfil their strategic requirements. These wireless communication systems followed Marconi’s model and consisted of a base station with a powerful transmitter that served a particular geographic area. Each of these base stations was independent and isolated from each other.

Today, cellular networks have taken the lead in pioneering wireless communication across the globe. Cellular systems consist of a cluster of base stations, served by low-power transmitters. These base stations are able to connect and communicate with each other, thus ensuring that a wider range of customers are served.

Criteria for selecting a microcontroller

The microcontroller for your wireless applications should have the following attributes:

(i) The microcontroller must be compliant with the following:

· IEEE 802.15.4 Networks

· Zigbee™ Networks

(ii) Ultra-low power MCU.

(iii) 128 MB RAM and ROM desirable.

(iv) Digital audio interface.

(v) Reliable performance.

(vi) Long lasting.

Important Facts and Figures

1901 – Marconi successfully transmits wireless data
1902 – First two-way communication across the Atlantic
1909 – Marconi wins the Nobel prize for his work in wireless transmission

Radio Transmission

1914 – First voice radio transmission
1920s – Mobile receivers installed in vehicles for the first time
1930s – Mobile transmitters developed and used for the first time
1935 – Frequency modulation (FM) demonstrated for first time

Birth of Mobile Telephony

1946 – Launch of Public Switched Telephone Network (PSTN)

1960s – Launch of Improved Mobile Telephone Service (IMTS)
1979 – Deployment of the first cellular communication system by NTT, Japan
1983 – Launch of Advanced Mobile Phone System (AMPS)
1989 – Launch of well-defined standards (European digital cellular standard) for GSM byGroupe Spècial Mobile
1991 – Launch of US Digital Cellular phone system
1993 – Launch of CDMA standards
1994 – GSM deployed in US. Relabelled as Global System for Mobile Communications
2001 – Launch of 3G in Japan
2007 – 200 million 3G users
2010 – Nation-wide auction of 3G spectrum in India

Wireless Local Area Networks

1990 – Introduction of IEEE 802.11 to define standards for Wireless Local Area Networks (WLANs)
1997 – Introduction of IEEE 802.11 WLAN protocol
1999 – Introduction of IEEE 802.11b WLAN protocol
1999 – Introduction of IEEE 802.11a WLAN protocol
2003 – Introduction of IEEE 802.11g WLAN protocol
2009 – Release of IEEE 802.11n WLAN protocol

Wireless Local Area Networks

1997 – 50 million cellular users in the US alone
2000 – Launch of Bluetooth standards/enabled devices
2008 – Cellular providers no longer required to provide analog support.

Future

By the year 2013, nearly one-third of the world’s population will have access to high speed mobile networks, namely, 3G and 4G.

4G is the fourth generation in mobile communication networks and is aimed at fulfilling the ever-growing business and consumer needs of customers across Europe, North America and Asia. Mobile manufacturers will be gearing up to design and develop mobiles capable of supporting 4G technology.

Wireless communication will play a major role in the medical domain. Doctors will be able to monitor and diagnose patients who are thousands of miles away thanks to wireless communication.

The current generation of youngsters finds it difficult to believe that their elders used a phone tied to the wall for most of their lives. Similarly, the next generation will find it amusing that we once had to stick something up to our heads to talk. Researchers have put forth the theory of embedded intelligence through implantation, where a simple thought is enough to wirelessly communicate with another individual anywhere in the world.