Radio Frequency ( RF ) technology has been applied into many device in our life including our mobile phone, The same Radio Frequency that has been developed from long time ago, Radio frequency ( RF ) is the oscillation rate of an alternating electric currrent / voltage or of a magnetic, electric or electromagentic field or mechanical system in the frequency range from 20 KHz to 300 Ghz. This roughly between the audio frencuencies and the lower limit infrared frequencies. These are the frequencies at which energy from an oscillating current can radiate off a conductor into space as radio waves. Different sources specify different upper and lower bounds for the frequency range. Energy from RF currents in conductors can radiate into space as electromagnetic waves (radio waves). This is the basic of radio technology. The radio spectrum of frequencies is divided into bands with conventional names designated by the International Telecommunications Union ( ITU ) :
Mobile networks based on different standards may use the same frequency range; for example, AMPS, D-AMPS, N-AMPS and IS-95 many of country use the 800 MHz frequency band. Moreover, people can find both AMPS and IS-95 networks in use on the same frequency in the same area that do not interfere with each other. This is achieved by the use of different channels to carry data. The actual frequency used by a particular phone can vary from place to place, depending on the settings of the carrier's base station. Cellular frequencies are the sets of frequency ranges within the Ultra High Frequency ( UHF ) band that have been assigned for cellular-compatible mobile devices, such as mobile phones, to connect to cellular networks. Most mobile networks worldwide use portions of the radio frequency spectrum, allocated to the mobile service, for the transmission and reception of their signals. Radio frequencies used for cellular networks differ in ITU Regions (Americas, Europe, Africa and Asia). The GSM standard, which appeared in Europe to replace NMT-450 and other standards, initially used the 850 Mhz ( Known as GSM ) 900 MHz ( known as EGSM ) band and 1,800 MHZ ( known as DCS ) in the beginning, besides The AMPS standard that used the cellular band ( 800 MHZ ) was replaced by IS-95 or CDMA and IS-136 or D-AMPS as Digital AMPS / TDMA. Many GSM phones support three bands that permited to use in many cpunties ( 900/1,800/1,900 MHz or 850/1,800/1,900 MHz) or four bands ( 850/900/1,800/1,900 MHz ) and more, for their mobilephone usually referred to as tri-band, quad-band phones and multiband phones or world phones with this such a phone people can travel internationally and use the same mobilephone.
Modern mobile phone networks use cells because radio frequencies are a limited, shared resource. Cell-sites and handsets change frequency under computer control and use low power transmitters so that the usually limited number of radio frequencies can be simultaneously used by many callers with less interference. A cellular network is used by the mobile phone operator to achieve both coverage and capacity for their subscribers. Large geographic areas are split into smaller cells to avoid line-of-sight signal loss and to support a large number of active phones in that area. All of the cell sites are connected to telephone exchanges (or switches), which in turn connect to the public telephone network. In cities, each cell site may have a range of up to approximately 0.80 km, while in rural areas, the range could be as much as 8.0 km. It is possible that in clear open areas, a user may receive signals from a cell site 25 miles (40 km) away. There are a number of different digital cellular technologies, including: Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), cdmaOne, CDMA2000, Evolution-Data Optimized (EV-DO), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT), Digital AMPS (IS-136/TDMA), Integrated Digital Enhanced Network (iDEN) and Long term Evolution ( LTE ) based on FDD or TDD, The transition from existing analog to the digital standard followed a very different path in Europe and the US.[19] As a consequence, multiple digital standards surfaced in the US, while Europe and many countries converged towards the GSM standard. The effect of frequency on cell coverage means that different frequencies serve better for different uses, each frequency provide different cell radius, cell area and relative cell count
Any phone connects to the network via an RBS (Radio Base Station) at a corner of the corresponding cell which in turn connects to the Mobile switching center (MSC). The MSC provides a connection to the public switched telephone network (PSTN). The link from a phone to the RBS is called an uplink while the other way is termed downlink. Radio channels effectively use the transmission medium through the use of the following
multiplexing and access schemes: frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and space division multiple access (SDMA). As the phone user moves from one cell area to another cell while a call is in progress, the mobile station will search for a new channel to attach to in order not to drop the call. Once a new channel is found, the network will command the mobile unit to switch to the new channel and at the same time switch the call onto the new channel, this is called Cellular handover.
GSM ( Global System for mobile communication )
GSM is the second generation ( 2G ) of cellular network system using multyplexing Time Division Multiple access (TDMA) technology, usually use Very Large Scale Integration (VLSI) Frequency Range / Band : 850 Mhz ( GSM ),, 900 Mhz ( EGSM ), 1800 Mhz (DCS) and 1900 MHZ (PCS) , the Group / Band of Frequency range for 2G mention below :
1. 850, TX: 824-849 Mhz, RX: 869-894 Mhz ( GSM ) > Lowband ( LB ) Band 5
2. 900, TX: 870-915 Mhz, RX: 935-960 Mhz ( E-GSM ) > Lowband LB ( LB ) Band 8
3. 1800, TX: 1710-1785 Mhz, RX: 1805-1880 Mhz (DCS) > Highband ( HB ) Band 3
4. 1900, TX: 1850-1910 Mhz, RX: 1930-1990 Mhz (PCS) > Highband ( HB ) Band 2
This GSM protocol also have advanced data packet service technology inside of it :
- High Speed Circuit Switch Data (HSCSD) : 64 Kbps - 100 Kbps ( long time ago )
- General Packet Radio Service ( GPRS ) : 171.2 kbps
- Enhanced Data rates for GSM Evolution (EDGE) : 384 kbps
UMTS (Universal Mobile Telecommunications System)
UMTS is the third generation (3G ) cellular technology that establishes by ITU. Use the new radio spectrum to increase the number of subscribers. This is in line with the industry's future needs for data service requests for the future. The UMTS system uses the same core as GPRS but uses a new radio interface. Core network that allows switching, routing, transport, and database functions for user traffic. The Core network consists of automatic circuit systems, such as MSC, VLR, and MSC Gateway (GMSC). The new radio network system at UMTS is called the UTRAN (UMTS Terrestrial Radio Access Network) and is connected to the Core network (CN) by GPRS via the IU ( UTRAN ) interface, which connects the Radio Control Network (RNC) and the Core Network. The new Radio network is WCDMA (Wide - Code Division Multiply Access) the Wide band CDMA technology was chosen as a liaison UTRAN in the air. UMTS-WCDMA is a Direct Sequence CDMA system where user data is reproduced by random bits to obtain a random code in the style of WCDMA. In UMTS, in addition to channeling, codes are used for data matching and contention. WCDMA is a third generation (3G) technology based on packet service using the standard Direct Sequence Spread Spectrum and RF modulation used is QPSK when uplink or downlink. The bandwidth standard used is 5 Mhz which can be increased up to 10 Mhz, 15 Mhz and 20 Mhz. While mobility support can be served up to 120 km / hour. HSDPA ( High-Speed Downlink Packet Access ) Implemented in UMTS ( 3G ) This mobile phone protocol sometimes called as 3.5G technology. The first phase HSDPA has a capacity of 4.1 Mbps, then next phase with acapacity of 11 Mbps and maximum peak data rate downlink capacity up to 14 Mbit/s. HSDPA provides an evolutionary path for the Universal Mobile Telecommunications System ( UMTS ) network that allows for greater data capacity usage (up to 14.4 Mbit / sec downward direction). designed to increase data transfer speeds 5x higher. HSDPA defines a new WCDMA channel, the high-speed downlink shared channel ( HS-DSCH ), which operates differently from the existing W-CDMA channel. Until now the use of HSDPA technology is only in the downstream direction of communication to mobile phones. In a static position this technology can download data up to 3.7 Mbps. and In a mobile state, someone who is driving on a toll road with a speed of 100 km / h, can access the internet with a speed of 1.2 Mbps, Range of data speed (DL) in UMTS up to 2.4 Mbps, Range of data speed ( DL ) HSDPA up to 4.8 Mbps. 2100 Mhz ( Band 1 / IMT ) is the Most General Band that use for 3G
LTE ( Long Term Evolution )
This technology known as Forth Generation ( 4G ) in the celluler networks technology, 3GPP Long Term Evolution is a high-level wireless data access communication standard based on GSM / EDGE and UMTS / HSPA networks. The network interface is incompatible with 2G and 3G networks, so it must be operated through a separate wireless spectrum. This technology is capable of downloading up to 300 Mbps speeds and 75 Mbps uploads. 3GPP Long Term Evolution, or better known as LTE and marketed as 4G LTE is a wireless communication standard based on GSM / EDGE and UMTS /HSDPA networks for high speed data access using cellular phones or other mobile devices. LTE uses Orthogonal Frequency Division Mutiplexing (OFDM) which transmits data through many radio spectrum operators, each of which is 180 kHz. OFDM transmits by dividing the data stream into many slower streams that are transmitted simultaneously. By using OFDM minimize the possibility of multi path effects. Increase the overall transmission speed, the transmission channel used by LTE is enlarged by increasing the quantity of radio spectrum operators without changing the radio spectrum channel parameters themselves.
as Mobilphone Technician you already know, When mobilephone connected to some cellular provider and said EDGE or maybe GPRS in the Signal Bar, it still connected to the networks use same 2G or GSM protocol, not the 3G or 4G when you trace this line on the schematics you only need to looking for "2G" words, or maybe "GSM" words or some other use LB and HB to mention the electronics circuit of 2G networks on their mobilephone schematics. On the other side 3G or 4G will use prefix UMTS / WCDMA and LTE for 4G, or some other will mention Band ( B1, B3, B7, B8, B38, B40, etc ) name only, or some other maybe use prefix words PRX ( primary rx ) and DRX ( diversity rx ) in the Netname to mention the use of this frequencies for 3G and 4G, or some other mention name of the networks, such as DCS ( 1800 Mhz ), PCS ( 1900 Mhz ), IMT ( 2100 Mhz ) etc.
This is Table of Band ( range / group of frequencies ) that used for cellular RF, including their Range of Upling and Downlink, all Cellular operator / Provide need to choose whic Frequencies that they wanna use to provides their services, ofcourse they need to follow the regulation in their countries.
Please note that your 4G ( LTE ) maybe use same frequencies with 2G ( GSM ) in your countries, its depend on Telecomunicaton Ministry / Departement on your country, some countries already 2300 Mhz and 2600 Mhz ( recomended ) some countries not using it yet, 4G networks / LTE support both frequency division duplexing (FDD) and time-division duplexing (TDD). I hope from now on, we know what the meaning of thoose Band 1 / B1, Band 2 / B2, Band 3 / B3, Band 8 / B8 etc, ww know LTE, UMTS / WCDMA, PRX, DRX, FDD, TDD, and all things that mention in this post, in any of mobilephone schematics specially RF cellular blocks, atleast i hope this simple post motivate you search more of literature of it
Lets learn togather
br,
Yongky Felaz
Pragmafix team
Mobile networks based on different standards may use the same frequency range; for example, AMPS, D-AMPS, N-AMPS and IS-95 many of country use the 800 MHz frequency band. Moreover, people can find both AMPS and IS-95 networks in use on the same frequency in the same area that do not interfere with each other. This is achieved by the use of different channels to carry data. The actual frequency used by a particular phone can vary from place to place, depending on the settings of the carrier's base station. Cellular frequencies are the sets of frequency ranges within the Ultra High Frequency ( UHF ) band that have been assigned for cellular-compatible mobile devices, such as mobile phones, to connect to cellular networks. Most mobile networks worldwide use portions of the radio frequency spectrum, allocated to the mobile service, for the transmission and reception of their signals. Radio frequencies used for cellular networks differ in ITU Regions (Americas, Europe, Africa and Asia). The GSM standard, which appeared in Europe to replace NMT-450 and other standards, initially used the 850 Mhz ( Known as GSM ) 900 MHz ( known as EGSM ) band and 1,800 MHZ ( known as DCS ) in the beginning, besides The AMPS standard that used the cellular band ( 800 MHZ ) was replaced by IS-95 or CDMA and IS-136 or D-AMPS as Digital AMPS / TDMA. Many GSM phones support three bands that permited to use in many cpunties ( 900/1,800/1,900 MHz or 850/1,800/1,900 MHz) or four bands ( 850/900/1,800/1,900 MHz ) and more, for their mobilephone usually referred to as tri-band, quad-band phones and multiband phones or world phones with this such a phone people can travel internationally and use the same mobilephone.
Modern mobile phone networks use cells because radio frequencies are a limited, shared resource. Cell-sites and handsets change frequency under computer control and use low power transmitters so that the usually limited number of radio frequencies can be simultaneously used by many callers with less interference. A cellular network is used by the mobile phone operator to achieve both coverage and capacity for their subscribers. Large geographic areas are split into smaller cells to avoid line-of-sight signal loss and to support a large number of active phones in that area. All of the cell sites are connected to telephone exchanges (or switches), which in turn connect to the public telephone network. In cities, each cell site may have a range of up to approximately 0.80 km, while in rural areas, the range could be as much as 8.0 km. It is possible that in clear open areas, a user may receive signals from a cell site 25 miles (40 km) away. There are a number of different digital cellular technologies, including: Global System for Mobile Communications (GSM), General Packet Radio Service (GPRS), cdmaOne, CDMA2000, Evolution-Data Optimized (EV-DO), Enhanced Data Rates for GSM Evolution (EDGE), Universal Mobile Telecommunications System (UMTS), Digital Enhanced Cordless Telecommunications (DECT), Digital AMPS (IS-136/TDMA), Integrated Digital Enhanced Network (iDEN) and Long term Evolution ( LTE ) based on FDD or TDD, The transition from existing analog to the digital standard followed a very different path in Europe and the US.[19] As a consequence, multiple digital standards surfaced in the US, while Europe and many countries converged towards the GSM standard. The effect of frequency on cell coverage means that different frequencies serve better for different uses, each frequency provide different cell radius, cell area and relative cell count
Any phone connects to the network via an RBS (Radio Base Station) at a corner of the corresponding cell which in turn connects to the Mobile switching center (MSC). The MSC provides a connection to the public switched telephone network (PSTN). The link from a phone to the RBS is called an uplink while the other way is termed downlink. Radio channels effectively use the transmission medium through the use of the following
multiplexing and access schemes: frequency division multiple access (FDMA), time division multiple access (TDMA), code division multiple access (CDMA), and space division multiple access (SDMA). As the phone user moves from one cell area to another cell while a call is in progress, the mobile station will search for a new channel to attach to in order not to drop the call. Once a new channel is found, the network will command the mobile unit to switch to the new channel and at the same time switch the call onto the new channel, this is called Cellular handover.
GSM ( Global System for mobile communication )
GSM is the second generation ( 2G ) of cellular network system using multyplexing Time Division Multiple access (TDMA) technology, usually use Very Large Scale Integration (VLSI) Frequency Range / Band : 850 Mhz ( GSM ),, 900 Mhz ( EGSM ), 1800 Mhz (DCS) and 1900 MHZ (PCS) , the Group / Band of Frequency range for 2G mention below :
1. 850, TX: 824-849 Mhz, RX: 869-894 Mhz ( GSM ) > Lowband ( LB ) Band 5
2. 900, TX: 870-915 Mhz, RX: 935-960 Mhz ( E-GSM ) > Lowband LB ( LB ) Band 8
3. 1800, TX: 1710-1785 Mhz, RX: 1805-1880 Mhz (DCS) > Highband ( HB ) Band 3
4. 1900, TX: 1850-1910 Mhz, RX: 1930-1990 Mhz (PCS) > Highband ( HB ) Band 2
This GSM protocol also have advanced data packet service technology inside of it :
- High Speed Circuit Switch Data (HSCSD) : 64 Kbps - 100 Kbps ( long time ago )
- General Packet Radio Service ( GPRS ) : 171.2 kbps
- Enhanced Data rates for GSM Evolution (EDGE) : 384 kbps
UMTS (Universal Mobile Telecommunications System)
UMTS is the third generation (3G ) cellular technology that establishes by ITU. Use the new radio spectrum to increase the number of subscribers. This is in line with the industry's future needs for data service requests for the future. The UMTS system uses the same core as GPRS but uses a new radio interface. Core network that allows switching, routing, transport, and database functions for user traffic. The Core network consists of automatic circuit systems, such as MSC, VLR, and MSC Gateway (GMSC). The new radio network system at UMTS is called the UTRAN (UMTS Terrestrial Radio Access Network) and is connected to the Core network (CN) by GPRS via the IU ( UTRAN ) interface, which connects the Radio Control Network (RNC) and the Core Network. The new Radio network is WCDMA (Wide - Code Division Multiply Access) the Wide band CDMA technology was chosen as a liaison UTRAN in the air. UMTS-WCDMA is a Direct Sequence CDMA system where user data is reproduced by random bits to obtain a random code in the style of WCDMA. In UMTS, in addition to channeling, codes are used for data matching and contention. WCDMA is a third generation (3G) technology based on packet service using the standard Direct Sequence Spread Spectrum and RF modulation used is QPSK when uplink or downlink. The bandwidth standard used is 5 Mhz which can be increased up to 10 Mhz, 15 Mhz and 20 Mhz. While mobility support can be served up to 120 km / hour. HSDPA ( High-Speed Downlink Packet Access ) Implemented in UMTS ( 3G ) This mobile phone protocol sometimes called as 3.5G technology. The first phase HSDPA has a capacity of 4.1 Mbps, then next phase with acapacity of 11 Mbps and maximum peak data rate downlink capacity up to 14 Mbit/s. HSDPA provides an evolutionary path for the Universal Mobile Telecommunications System ( UMTS ) network that allows for greater data capacity usage (up to 14.4 Mbit / sec downward direction). designed to increase data transfer speeds 5x higher. HSDPA defines a new WCDMA channel, the high-speed downlink shared channel ( HS-DSCH ), which operates differently from the existing W-CDMA channel. Until now the use of HSDPA technology is only in the downstream direction of communication to mobile phones. In a static position this technology can download data up to 3.7 Mbps. and In a mobile state, someone who is driving on a toll road with a speed of 100 km / h, can access the internet with a speed of 1.2 Mbps, Range of data speed (DL) in UMTS up to 2.4 Mbps, Range of data speed ( DL ) HSDPA up to 4.8 Mbps. 2100 Mhz ( Band 1 / IMT ) is the Most General Band that use for 3G
LTE ( Long Term Evolution )
This technology known as Forth Generation ( 4G ) in the celluler networks technology, 3GPP Long Term Evolution is a high-level wireless data access communication standard based on GSM / EDGE and UMTS / HSPA networks. The network interface is incompatible with 2G and 3G networks, so it must be operated through a separate wireless spectrum. This technology is capable of downloading up to 300 Mbps speeds and 75 Mbps uploads. 3GPP Long Term Evolution, or better known as LTE and marketed as 4G LTE is a wireless communication standard based on GSM / EDGE and UMTS /HSDPA networks for high speed data access using cellular phones or other mobile devices. LTE uses Orthogonal Frequency Division Mutiplexing (OFDM) which transmits data through many radio spectrum operators, each of which is 180 kHz. OFDM transmits by dividing the data stream into many slower streams that are transmitted simultaneously. By using OFDM minimize the possibility of multi path effects. Increase the overall transmission speed, the transmission channel used by LTE is enlarged by increasing the quantity of radio spectrum operators without changing the radio spectrum channel parameters themselves.
as Mobilphone Technician you already know, When mobilephone connected to some cellular provider and said EDGE or maybe GPRS in the Signal Bar, it still connected to the networks use same 2G or GSM protocol, not the 3G or 4G when you trace this line on the schematics you only need to looking for "2G" words, or maybe "GSM" words or some other use LB and HB to mention the electronics circuit of 2G networks on their mobilephone schematics. On the other side 3G or 4G will use prefix UMTS / WCDMA and LTE for 4G, or some other will mention Band ( B1, B3, B7, B8, B38, B40, etc ) name only, or some other maybe use prefix words PRX ( primary rx ) and DRX ( diversity rx ) in the Netname to mention the use of this frequencies for 3G and 4G, or some other mention name of the networks, such as DCS ( 1800 Mhz ), PCS ( 1900 Mhz ), IMT ( 2100 Mhz ) etc.
This is Table of Band ( range / group of frequencies ) that used for cellular RF, including their Range of Upling and Downlink, all Cellular operator / Provide need to choose whic Frequencies that they wanna use to provides their services, ofcourse they need to follow the regulation in their countries.
Please note that your 4G ( LTE ) maybe use same frequencies with 2G ( GSM ) in your countries, its depend on Telecomunicaton Ministry / Departement on your country, some countries already 2300 Mhz and 2600 Mhz ( recomended ) some countries not using it yet, 4G networks / LTE support both frequency division duplexing (FDD) and time-division duplexing (TDD). I hope from now on, we know what the meaning of thoose Band 1 / B1, Band 2 / B2, Band 3 / B3, Band 8 / B8 etc, ww know LTE, UMTS / WCDMA, PRX, DRX, FDD, TDD, and all things that mention in this post, in any of mobilephone schematics specially RF cellular blocks, atleast i hope this simple post motivate you search more of literature of it
Lets learn togather
br,
Yongky Felaz
Pragmafix team
