a) 1G: (Analog)
- When wireless generation started, it was analog communication. That generation is 1G.
- They used various analog modulation for data transfer.
- Now when the communication migrated from analog to digital, the foundation of latest communication were led. Hence came 2G.
Note:1G = Analog
b) 2G: (Voice+SMS/MMS)
- It marked the start of digital voice communication era. Main motive of this generation was to provide secure and reliable communication channel.
- It implemented the concept of CDMA and GSM. Provided small data service like sms and mms.
Note: 2G internet services came after the 3G establishment.
- 2G = digital, voice (GSM)
- 2.5G added data (GPRS)
- 2.75G faster data (EDGE)
c) 3G:(Voice + Data)
- Then came the time of some decent speed internet connection and awesome voice channel.
- They exploited area of Wideband-CDMA(W-CDMA), provided better bandwidth and better connectivity even during motion(like in vehicle, train).
- There was some technical shift towards HSPA for better data communication and to maintain 4G compatibility.
- 3G = digital, supported data, packet switched (WCDMA, EvDO)
3.5G faster data (HSPA)
d) 4G: (Only DATA and Voice over data)
- Era of broadband wireless. This in the making and have been successfully deployed in only some part of the world.
- Best aspect of 4G is the use of data services for everything.
- Internet is the back bone and even voice call is done over internet. There is no separate voice channel. This allows usage of wider bandwidth in the communication channel for data.
- 4G: wireless broadband
(most people say this is LTE, some people are waiting for an upgrade to LTE-A)
e) 5G: (High Speed and Low data rate)
- The major issue with 5G technology is that there is such an enormously wide variation in the requirements: super fast downloads to small data requirements for IoT than any one system will not be able to meet these needs.
- 5G is not just a mobile technology. It is ubiquitous access to high & low data rate services.
- Much faster. Likely to be real ~2020
| Suggested 5G Wireless Performance
||10 000 times current network
|Peak data rate
|Cell edge data rate
||< 1 ms
Table1.1 Comparison of 1G to 5G technology
1.1 Frequency division multiple access (FDMA):
- It is a technology by which the total bandwidth available to the system is divided into frequencies. This division is done between non overlapping frequencies that are then assigned to each communicating pair (2 phones)
- FDMA is used mainly for analog transmission. Its not that this technology is not capable of carrying digital information, but just that it is not considered to be an efficient method for digital transmission.
Example: Imagine how FM radio works. All the radios have their own frequency bands and they send their signals at the carefully allocated unique frequencies within the available bands.
1.2 Code division multiple access (CDMA):
- Unlike FDMA, CDMA separates calls by code. Every bit of a conversation is been tagged with a specific and unique code.
- The system gets a call, it allocates a unique code to that particular conversation, now the data is split into small parts and is tagged with the unique code given to the conversation of which they are part of. Now, this data in small pieces is sent over a number of the discrete frequencies available for use at any time in the specified range.
- The system then at the end reassembles the conversation from the coded bits and deliver it.
Example: Recollecting your luggage at the end of the flight journey. When you check in, a tag with a code is given to you which is also given to your luggageJ And at the destination, you collects your luggage on the basis of thatJ I know you will say that you recognize your bag, but then I have a habit of always matching the codes of my bag and the one on the tag given to me and that is how I become sure of not picking up the wrong luggage.
1.3 Time division multiple access (TDMA):
- In TDMA the division of calls happens on time basis. The system first digitizes the calls, and then combines those conversations into a unified digital stream on a single radio channel.
- It divides each cellular channel into three time slots that means three calls get put on a single frequency and then, a time slot is assigned to each call during the conversation, a regular space in a digital stream.
- The users transmit in rapid succession, one after the other, each using its own time slot. This allows multiple stations to share the same transmission medium.
Example :Radio frequency channel) while using only a part of its channel capacity.
Note:This technology enables three different users to use one frequency at the same time, this technology is the one used in our GSM system.
Below is the table given:
Table 1.1 Comparison between TDMA/FDMA/CDMA
Below is the graphical representation with respect to frequency and time of respectively access fig 1.1
CDMA and GSM
CDMA: Code Division Multiple Access is a technology developed by Qualcomm in the United States, and it is currently the dominant network standard in North America.
GSM: Global System for Mobile communications was invented in 1987 by the GSM Association, an international organization dedicated to developing this standard worldwide.
Below are the different parameters discussed in detail of CDMA vs. GSM
1.1 Coverage of CDMA vs. GSM
- It is mostly used in America and some parts of Asia. It is currently making progress in other parts of the world, but the coverage is still limited compared to the GSM technology.
- CDMA generally offers a better coverage than GSM in some rural areas because it was deployed earlier.
- Its network reaches over 270 million users worldwide.
- GSM being an international standard, it is better suited for international roaming, provided you own a quad-band cell phone (850/900/1800/1900 MHz).
- The GSM network is also well established in North America, but not as much as the CDMA network yet. Its network reaches over a billion users worldwide.
Note: CDMA is prominent in North America, but GSM reaches a lot more users worldwide (about 1 billion vs 270 million).
1.2 Data Transfer
- The best data transfer technology it has to offer is the EVDO technology, allowing for a maximum download speed of about 2mb/s (about 700kbps in practice), which is similar to what a DSL line has to offer.
- GSM allows for a maximum download speed of 384kbps (around 140kbps in practice). More technologies are being developed on top of EDGE such as HSDPA to boost the transfer rate to over 384kbps in practice. This technology requires an EDGE-ready cell phone.
Note: CDMA offers faster data download and would therefore be the favoured choice for data transfer. GSM is catching up fast however, but its EDGE technology is subject to interference’s.
1.3 Phone Identification (SIM card)
- Your account information is programmed into your cellular phone. If you want to change your phone, you have to contact your carrier and have them reprogram your new phone.
- You will also need to re-enter your contact list and calendar information into your new phone. If you have a lot of contacts, your carrier might be able to help you perform this task.
- Some CDMA 2000 cell phones support R-UIM cards (Removable User Identity Module) which are used to store account information and contact lists, but these are not very common in North America yet.
- Your account information along with your contact list and other personal data are stored on a SIM card (Subscriber Identity Module).
- It is a small chip you can freely remove from your phone. When you get a new mobile device, you can simply insert your SIM card into it and it will work with your current account information and contact list.
- If you travel to another country, it might even be possible to purchase a prepaid SIM card which you can use to avoid roaming fees.
Note: GSM is a clear winner here. The SIM card technology offers many advantages if you plan to travel or switch phone often. CDMA phones are slowly catching up with R-UIM cards, but cell phones that make use of this technology as still rare.
Which technology is the best?
It depends upon the requirement of particular user-
1. Is international roaming important to user?
- If user travel a lot to foreign countries, user might want to opt for a GSM phone for a better coverage.
2. If user transfer a lot of data using the phone?
- If user intend to use the phone for mobile web browsing, watching television or downloading MP3s, user might be better off with a CDMA phone.
- Currently, it offers the best data transfer speed with its EVDO technology and is the clear winner for now.
3. if user plan to change phone often?
- If user do, a GSM phone is best for you since you can swap the SIM card to a new device without having to re-enter your personal data.
Table 1.1 ( comparison between CDMA vs GSM)
Parameter CDMA GSM
|| Code Division Multiple Access
||Global System for Mobile communication
|| Internal Memory
||SIM (subscriber identity module) Card
|Global market share
|| Dominant standard in the U.S.
||Dominant standard worldwide except the U.S.
|| There is one physical channel and a special code for every device in the coverage network. Using this code, the signal of the device is multiplexed, and the same physical channel is used to send the signal.
||Every cell has a corresponding network tower, which serves the mobile phones in that cellular area.
|| Less Accessible
| Single (850 MHz)
||Multiple (850/900/1800/1900 MHz)
|| Handset specific
||SIM specific. User has option to select handset of his choice.
1.1 History of Wireless Communication
The first wireless networks were developed in the Pre-industrial age.These systems transmitted information over line-of-sight distances using smoke signals, torch signaling, flashing mirrors, signal flares, or semaphore flags.
- 1838-These early communication networks were replaced first by the telegraph network (invented by Samuel Morse in 1838) and later by the telephone.
- 1971-The first network based on packet radio, ALOHANET, was developed at the University of Hawaii in 1971. This network enabled computer sites at seven campuses spread out over four is lands to communicate with a central computer on Oahu via radio transmission.
- 1885-In 1895, a few decades after the telephone was invented, Marconi demonstrated the first radio transmission from the Isle of Wight to a tugboat 18 miles away, and radio communications was born.
1990-Packet radio networks also found commercial application in supporting wide area wireless data services.
These services, first introduced in the early 1990’s, enable wireless data access (including email, file transfer, and
web browsing) at fairly low speeds, on the order of 20 Kbps.
1.2 Current Wireless Communication Systems
1.2.1 Cordless Phones
- The base units of cordless phones connect to the PSTN in the exact same manner as a landline phone, and thus they impose no added complexity on the telephone network.
- The ﬁrst cordless systems allowed only one phone handset to connect to each base unit, and coverage was limited to a few rooms of a house or ofﬁce.
- In Europe and Asia the second generation of digital cordless phones (CT-2, for cordless telephone, second generation) have an extended range of use beyond a single residence or ofﬁce. Within a home these systems operate as conventional cordless phones.
- A more advanced cordless telephone system that emerged in Japan is the Personal Handy phone System (PHS).The PHS system is quite similar to a cellular system, with widespread base station deployment supporting hand off and call routing between base stations.
1.2.2 Wireless LANs
- Wireless LANs provide high-speed data within a small region, e.g. a campus or small building, as users move from place to place.
- All wireless LAN standards in the U.S. operate in unlicensed frequency bands. The primary unlicensed bands are the ISM bands at 900 MHz, 2.4 GHz, and 5.8 GHz, and the Unlicensed National Information Infrastructure.
- These ﬁrst generation wireless LANs were based on proprietary and incompatible protocols. Most operated within the 26 MHz spectrum of the 900 MHz ISM band using direct sequence spread spectrum, with data rates on the order of 1-2 Mbps.
- The second generation of wireless LANs in the U.S. operate with 80 MHz of spectrum in the 2.4 GHz ISM band. A wireless LAN standard for this frequency band, the IEEE 802.11b standard, was developed to avoid some of the problems with the proprietary ﬁrst generation systems.
1.2.3 Satellite Networks
- A satellite communications system uses satellites to relay radio transmissions between earth’s terminals.
- The two types of communications satellites are ACTIVE and PASSIVE. A passive satellite only reflects received radio signals back to earth. An active satellite acts as a REPEATER; it amplifies signals received and then re-transmits them back to earth. This increases signal strength at the receiving terminal to a higher level than would be available from a passive satellite.
- The most appealing use for satellite system is broadcasting of video and audio over large geographic regions.
- In the U.S. approximately 1 in 8 homes have direct broadcast satellite service, and satellite radio is emerging as a popular service as well. Similar audio and video satellite broadcasting services are widespread in Europe.
- GPS stands for Global Positioning System,GPS is indeed a remarkable technological development.
- GPS satellites first orbited in 1983 and from that time efforts have been under way to include GPS in everything from marine navigation to guided missiles to tracking golf balls.
- Currently there are over 75 manufacturers of GPS products for applications such as Marine, Land, and Air Navigation, Surveying, Resource Management, and tracking applications for vehicles, people.
- GPS contribution to the development of future satellite and terrestrial wireless communications technologies may well be its single most important benefit to the world. Below is the table given for Wireless technologies and associated characteristics.Table 1. Wireless technologies and associated characteristics.
1.3 Evolving Wireless Communication System
1.3.1 Ad-Hoc Networks
- An Ad-Hoc network is a cooperative engagement of collection of mobile hosts with the intervention of any centralized Access Point.The idea to design each Mobile Hosts as a ‘specialized router’, which periodically advertises its view of the inter-connectivity topology with the mobile hosts in the network.
- An ad-hoc network is a WLAN in which mobile or portable devices are part of the network but only when they are in a relegated, close proximity.
- There is no fixed infrastructure, and information is forwarded in a peer-to-peer mode using multi-hop routing. Military applications for Ad-Hoc networks include a group of close-by soldiers who can share the information in their notebook computers using RF signals.
- Numerous civilian applications are being explored. Home net working is replacing WLANs in home devices is to employ a short-range frequency-hopping radio link of Bluetooth technology and connect a cellular telephone to laptops, printers,PDAs, desktops, fax machines,keyboards, joysticks, and other peripherals.
1.3.2 Sensor network
- Sensor networks [3, 5–7] are the newest of wireless networks in which a large number of tiny immobile sensors are planted on an ad-hoc basis to sense and transmit some physical characteristics of the environment.
- The information from sensors is aggregated on a “data centric basis.” Battlefield surveillance with a large number of sensors dropped from an airplane in enemy territory is the most noted example.
- Other potential commercial fields include machinery prognosis, bio sensing, and environmental monitoring.
- Data integration and Sensor Web-The data gathered from wireless sensor networks is usually saved in the form of numerical data in a central base station. Additionally, the Open Geospatial Consortium (OGC) is specifying standards for interoperability interfaces and metadata encoding that enable real time integration of heterogeneous sensor webs into the Internet, allowing any individual to monitor or control Wireless Sensor Networks through a Web Browser.
Considering the rate at which so many things are being connected wire lessly to the Internet, it’s be coming easier to imagine how cellular connectivity is expect to signal traffic to and from 50 billion emerging devices with in the next decade. While wireless carriers, chip set manufacturers, tower owners and infrastructure vendors have a lotto be excited about, there is also a growing prospect of greater Wi-Fi adoption. The technology, which distinguishes itself as one that runs on unlicensed spectrum, has been growing steadily and is increasingly seen as a fill-in alternative for certain locations where cellular signals are either too weak or too complex and ineffective due to cost.