4G LTE Mobile 

 SANTI PADA CHAKRABORTY, FELLOW OF INSTITUITIONS OF ENGININEERS (INDIA), EX-SUPERINTENDING ENGINEER (ELECTRICAL), WBSEB.   spchakra1324@gmail.com                                        

    Introduction: - Mobile communication technologies have revolutionized communications and connectivity by adding mobility. Upgrade from 1G to evolution of 4G access technologies in less than 5 years has taken place.. The use of mobile phones is increasing day by day. At present, nearly 90 million mobile phones are being used in India.  At first, talking on the cell phone or sending SMS message was simple. But the modern cell phone can be connected to the Internet  network. Moreover, the needs of human nature are such that the people always want fastest communication. As a result LTE technology is daveloped. LTE technology 4G i is fast and advanced.

4G systems.

The fourth Generation mobile (4G) system is all internet protocol ( IP) based network system.  4G technologies provide high speed, high quality, high capacity, security and low cost services for voice and data services, multimedia and internet over IP.

 It provides wireless services anytime and anywhere, terminal mobility is a key factor in 4G. 4G introduced new physical radio interface known as Evolved UMTS Terrestrial Radio Access (E-UTRA) and new packet –switching based core network called as Evolved Packet Core (EPC).  IP-based network architecture, allows seamless   voice and data to GSM, UMTS or CDMA2000 technology.

4G has following   characteristics:

Standards - Long-Term Evolution Time-Division Duplex (LTE-TDD and LTE-FDD) Mobile WiMAX standard (802.16m standardized by the IEEE

Speed - 100Mbps while moving and 1Gbps while stationary with the help of following features

IP telephony

New frequency bands, wider channel frequency bandwidth

Multiplexing/Access Technologies - OFDM, MC-CDMA, Bandwidth - 5–20 MHz, optionally up to 40 MHz

Frequency Bands: - LTE standard covers a range of many different bands.

In North America, 700, 750, 800, 850, 1900, 1700/2100 (AWS), 2300 (WCS) 2500 and 2600 MHz are used (bands 2, 4, 5, 7, 12, 13, 17, 25, 26, 30, 41); 2500 MHz in South America;

700, 800, 900, 1800, 2600 MHz in Europe (bands 3, 7, 20); 800, 1800 and 2600 MHz in Asia (bands 1, 3, 5, 7, 8, 11, 13, 40)

1800 MHz and 2300 MHz in Australia & New Zealand (bands 3, 40).

Services - Mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, 3D television, and cloud computing, manage multi broadcast streams and handle quick-moving mobile phones , Digital Video Broadcasting (DVB),  smooth  connection  across different  networks and automatic roaming between different wireless networks

It is a huge change in the mobile and video conferencing.  

4G implementation variants:

The LTE standard supports only Packet Switching & is all IP Network. Voice calls in GSM, UMTS and CDMA2000 are circuit switched, so with the adoption of LTE, carriers will have to modify their voice call network.  However since it requires lot of infrastructure changes, three different approaches are

   It's easy to say now that the future of mobile communications and mobile generation is revolutionary enhancements over the world coming to grip. From 1G to 4G mobile phone has evolved. 5G and will come after wards. 

From 1G to 3G mobile networks are being discussed below.        

      1G, 1 ^st Generation, it is a analogue system. 2 ^nd Generation is Digital system. These are GSM (Global System for Mobile) and CDMA (Code Division Multiple Access) 2 ^nd Generation Mobile Communication System sends voice at slow speed. GSM launched in 1990 , then comes CDMA. 2G narrow band digital-based. Transmission of digital data signals on 2G transmission reduced complexity and voice quality has improved a lot. 2 ^nd generation sends data at limited speed 9.6 kbps to 19.2 kbps. It can only send SMS and voice. General 2G Network 800/900 Mhz or 1800/1900 MHz spectrum range. The 2G Bandwidth 30-200 Khz.   

   2.5G - between 2G and 3G to 2.5G (GPRS) arrived. After 2G technology advanced to the  2.5G GPRS (General Pocket Radio Service) comes. Its has more bandwidth, packet routing and multimedia convention aspects are there. Circuit switching and packet switching for voice and data are used to send. Speed is 56 kbps. In 2.5G the amount of radio wave is much less. It has changed the structure of the mobile phone small. However, not much improvement was there. The world is talking. No Email, Web browsing and video are found, but it helps evolve 3G. 

     GPRS EDGE speed only 236.8 kbps. 

   3G - which has a bunch of 3G technology such as WCDMA, EV-DO and HSPA, etc.. It is 3 ^rd Generation mobile  launched in Japan in 2001.  It uses a wide banding network. Wide banding has improved voice quality.  Mobile Internet speed  2Mbps are available. The 3G bandwidth is 1.6GHz and 2.5 GHz. Data can be sent, voice and video calling can be done. Can send files and internet surfing can be done. Download speed is low. video is available

    4G LTE: -  4G UMTS (Universal Mobile Telecommunication System) upgrade was introduced. It's standard UMTS is developed by 3GPP.                                              

    What is called 4G LTE technology wireless? LTE (Long Term Evolution) is the Third Generation Partnership Project. 3GPP has developed very good technologies. It is well-known that GSM, GPRS, EDGE, UMTS, HSPA and LTE and LTE-A has been developed 3GPP. 

   The 3GPP is UMTS hybrid circuit switched / packet switched core networks converted into packet-only core network that enables higher data rates and higher throughput , delay or latency of data transfer rate is less, less costly and increase in efficiency. LTE radio wave technology has been developed. 

 Spectrum channel bandwidth 1.25 MHz to 20 MHz is found and is used efficiently.

  LTE promises data rates of 50 Mbps to 100 Mbps download, upload cell within a radius of 50 km.  400 to 200 customers in a cell be connected.  Speed is 100Mbps speed ও 1Gbps is in still condition.  

It can use Channel bandwidth from 1.4 MHz to 20 MHz LTE 4G uplink and down link. There are six different bandwidth. These are 1.4 MHZ, 3MHZ, 5 MHZ, 10 MHz, 15 MHz and 20 MHz. In addition, the subcarrier apart from one another is 15KHz. LTE UMTS 1800 MHz frequency band and uses the serial upgrade technology. Reduces the frequency range and signal more than a lot of distance (penetration) cannot go. 

  Key Parameters (TABLE)

            3G                                                  4G

Frequency Band 1.8-2.5 GHz          2-8 Ghz

Bandwidth 5-20 MHz                        5-20 MHz

Data Rate Upto 2 Mbps                   Upto 20 Mbps

Access W-CDMA MC-CDMA or OFDM (TDMA)

Switching circuit / packet switch.

    LTE supports speeds up to 360 kmph intercell handover soft.  At 120 Kmph (vehicle speed)   4G LTE speed mobility will work well. 4G LTE supports fixed position (0 kmph), during walking (10 kmph), the vehicle running speed (120kmph) and the car speed (350 kmph) or more. Up to 500 kmph to 350 kmph speed 4G can work.   

    UMTS 3G technologies, which is the seed of the next WCDMA, HSDPA, HSUPA, and HSPA based LTE is a normal GSM / UMTS carrier's upgrade path. The modern version of UMTS LTE //UMTS rather than replaces.

    4G LTE smartphone with 4G network laptop modem, will support hotspot. 4G Internet surfing  can  download quickly. Video calling, video conferencing  can be done, on-line TV can be viewed.Titanic movie can be downloaded in 1 minute. It will initiate Lightning speed. The highest speed of 4G  will be 100 Mbps.  

    How 4G LTE works: -  LTE technology is very advance. LTE works in radio wave. In 4G LTE from Base station (BS) Antenna will transmit and receive the radio frequency signals from the mobile phone.  Base station Antenna connects a mobile to all land line and mobile phones.

 Base station is low-power radio transmitter and is to be installed in the rooftop or mast in area where mobile connections is to be given. Area are called cell. For seamless Connection cell should overlap. A BS can cater fewer mobile connections at a time. A outdoor base station can be 10W to 40W power. Where, a TV transmitter power is more than 1000 times. Radio Wave exposer in public areas would be lower than the safety limit. Radio intensity decreases as distance from base station increases. More base stations will have to be installed if the number of customers increases.

  Reliance Jio 4G

On  5.9.16 Reliance Jio has launched full-fledged 4G service  in the country.

Airtel 4G use TDD-LTE, Reliance 4G Jio services launched at 1800 MHz band using FDD-LTE technology overall leveraging TDD- FDD technology leverage.

Pure 4G:- Reliace Jio  is giving pure 4G service. Reliace Jio 4G network are offering voice call , SMS and data in pure 4G. where  Airtel, Vodafone, Idea offer voice calling in 2G, and 3G  and data in pure 4G.

Reliance JioFi offer  pure 4G service in voice call and also data in 4G.  Airtel, Vodafone and Idea use 3G and 2G network for  voice call and SMS. These automatically transferred to 3G or 2G. 4G Jio voice call is on pure 4G.

Voice over LTE, or VoLTE, is similar to VoIP (Voice over Internet Protocol), which is Internet voice applications such as Skype and  use to support voice calls over a broadband connection.

Why VoLTE is necessary?  The problem with Voice over LTE is that 4G LTE is a data-only networking technology, so it doesn’t  support voice calls. While 3G and 2G were primarily designed for voice calls  and data was added to them later.

As such it’s been necessary to create new protocols to support voice calling over 4G and it’s a big job, requiring upgrades across the entire voice call infrastructure. There’s no one standard for this, with different networks creating their own solutions.

Previous cellular networks, such as 2G and 3G, were designed mainly to carry voice calls-- data service support added later. LTE turns the network around and uses Internet Protocol packets for all communications. As such, it doesn't support traditional voice-call technology, so a new protocol and applications for Voice over LTE are needed.

 Your voice quality will not reduce in VoLTE or voice over LTE  even if your data is turned on while making and receiving a call. Where as in LTE the voice quality reduces if you keep your data on.

   Advantages Volte: Superior call quality, Improved coverage and connectivity, Better battery life, Video calling 

 Three is fully relying on its 800MHz spectrum for VoLTE calls.

SPEED:- Jio VoLTE  is giving  real 4G at high speed. Jio speed is 60Mpps, 70 Mpps ও 150Mbps. Reliance Jio pan-India has launched 4G service.  

Reliance JioFi:- Jio's 4G LTE Hotspot has started.

Reliance JioFi gives pure 4G service of  voice call using 4G network. Airtel Vodafone and Idea use 3G ও 2G network for voice call, SMS. Voice call, SMS are automatically transferred to 3G or 2G. They offer  data  in pure 4G. Jio call is done in 4G.

In a nutshell, VoLTE allows voice to become just another app that rides on a data network. The new protocol may bring faster, better voice calls and even video chat tied to your cell phone service and number. Voice-minutes billing will go away.

methods  basically "tunneled" data inside of voice-call connections.

  

      FDD-LTE versions of  LTE standard, defined by 3GPP uses FDD (frequency division duplex) or 'paired spectrum'. The uplink is on band (say 10MHz wide at 2.600GHz) and the paired downlink is another 10MHz at a sepated frequency (eg 2.720GHz) This is sometimes called 10+10. It is symmetric and uses two frequencies one up, one down.

In LTE the differences are nearly all in the duplex method (implication in radio and allocation / scheduling) but it is very sensible / credible to make dual mode systems. There are no significant differences in applications or usage.

   TD-LTE is Time division. It has one frequency band, and switches between up and down in turn as a 'ping-pong'.

    As stated above,Airtel 4G use TDD-LTE, Reliance 4G Jio services launched at 1800 MHz band using FDD-LTE technology overall leveraging TDD- FDD technology leverage
    Multiple Access:-In any cellular systems must have access to multiple numbers of consumers together. There should be multiple access schemes. Variety of multiple access schemes are there such as TDMA, CDMA, or OFDMA, etc. These are the main way mobile radio system technology works.

  OFDMA (Orthogonal Frequency Division Multiple Access) is  a multiple access which  LTE technology  is using,  because  it is more suitable for broadband or  more data transmission. Orthogonal Frequency Division Multiplexing OFDM is a radio wave modulation technique for increasing amounts of digital data  transmitted via radio wave. In this manner the number of radio signals (closely spaced) to be around a lot of orthogonal where data is broken down into sub-carrier. Different frequencies are transmitted together with the receivers. Orthogonal sub-carrier frequency OFDM reduce signal  interference or reduce the amount of crosstalk between transmission channel. Spread spectrum radio technology  is applied to 3G  but not  applied to 4G. Multi-carrier OFDMA Transmission is used instead. OFDMA is a multi-user version of OFDM Modulation Scheme and the digital time division multiple access, but it is not like the TDMA and CDMA, or code and is not shared, it's frequency domain equalization system. A divided three-time slot TDMA channel sends data. CDMA is a channel that sends data to a receiver, and is identified by a code. There is more to the effectiveness of OFDMA data packets sent shares band narrow channel. OFDM multiple access scheme for the two methods are used in cellular technology, for an uplink and a down link. BS link, which sends down signal to mobile phone all the data it receives and collects. Based on data from one or more carrier in uplink handset is assigned to each of the cellular network to send and receive data to control. spectral efficiency of OFDMA MIMO is more. Spectral efficiency or spectrum efficiency or bandwidth is the  information rate which in any  bandwidth can be send in specific communication systems. It can send much more  bit rate though much higher multi-path radio signal (echo) is spread

   Full Duplex - Each party can transmit and receive data simultaneously. The communication is two-way and two frequencies are used. one for transmitting and one for receiving.  

    
 FIG  4G LTE MIMO antenna

   MIMO:- Multiple Input Multiple Output technology  uses multiple antennas to make use of reflected signals to provide gains in channel robustness and throughput.

     MIMO (multiple input, multiple output) is an antenna technology for wireless communications in which multiple antennas are used at both the source (transmitter) and the destination (receiver). MIMO is one of several forms of smart antenna technology . MIMO can increase throuput in scattering condition. Scattering signal is reflected in enviroment. Spread signal in different path and signal to noise ratio  are utilised to improve throughput without purchasing more spectrum.

Several different diversity modes are available and provide a number of advantages: Time diversity, frequency diversity,and apace diversity.

  Space diversity in the broadest sense of the definition is used as the basis for MIMO. It uses antennas located in different positions to take advantage of the different radio paths that exist in a typical terrestrial environment.

MIMO is  a radio antenna technology as it uses multiple antennas at the transmitter and receiver to enable a variety of signal paths to carry the data, choosing separate paths for each antenna to enable multiple signal paths to be used.

Antennas are multiple spatially distributed i.e. the use of multiple antennas located at different points. Accordingly MIMO wireless systems can be viewed as a logical extension to the smart antennas that have been used for many years to improve wireless.
It is found that between a transmitter and a receiver, the signal can take many paths. Additionally by moving the antennas even a small distance the paths used will change. The variety of paths available occurs as a result of the number of objects that come come to the side or in the direct path between the transmitter and receiver. By using MIMO, these additional paths can be used to advantage. They can be used to provide strength s to the radio link by improving the signal to noise ratio, or by increasing the link data capacity.
Use of  multiple antennas, MIMO wireless technology  will increase the capacity of a given channel while still obeying Shannon's law. By increasing the number of receive and transmit antennas it is possible to linearly increase the throughput of the channel with every pair of antennas added to the system. This makes MIMO wireless technology one of the most important  wireless techniques to be employed in recent years.
As commodity for radio communications systems, spectral bandwidth is becoming becoming costly, MIMO  techniques  are using  to available bandwidth more effectively.