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The main reason of selecting a lower frequency for up-link channel in GSM is because of free space path loss. The more is the frequency the more is the loss.
As mobile phones, being a battery driven device, have limitation in terms of power we should always look for lower path loss. Whereas BTS antennas can transmit the signal (in down-link channel) with a comparatively high power, which will compensate the path loss.
And that is why it is chosen to have lower frequency for up-link and higher frequency for down-link in GSM standards. The same theory applies in almost all type of radio communication.
NOTE: Frequency and power are independent of each other. For example you can control the transmission power of BTS antenna, which still transmits in the same frequency.
Wiki User
∙ 13y ago
Wiki User
∙ 13y agoBecause GSM work in multiplex mode it transmit and receive at the same time and if you use the same frequency the receiver section will receive the same signal that is transmitted, that is also why the frequencies is so far apart, is to prevent second channel interference so thatswhy bothfrequencyare different.
Wiki User
∙ 16y agoHi. If you mean why is the downlink frequency higher than the uplink frequency, it's because - all other things being equal - signals propagate for less distance the higher the frequency gets. Having the (slightly) lower frequency transmitting from the handset allows for a slight advantage in achievable propagation distance from the handset to the base station. The base station has more power and larger antennas, so it can usually transmit further than the mobile station.
Wiki User
∙ 13y agoUp-link freq is higher than down-link freq in GSM
You answer is wrong
Correct answer is that, down-link frequency is greater than the up-link frequency in GSM.
Up-link Frequency = 890 MHz - 915 MHz
Down-link Frequency = 935 MHz - 960 MHz
Wiki User
∙ 12y agoSince path loss is directly propotional to frequency so the Mobile station transmits at lower frequencies in the uplink channel in order to conserve battery power. BTS downlink signal can however afford to experience path loss and still provide good enough transmission to the receiver(mobile station).
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What is E-GSM?
WHEN I WAS IN THE U.S. ARMY FROM 1966 THRU 1968, I WAS IN A UNIT KNOWN AS "EGSM" IN GERMANY. IT STOOD FOR "EQUIPMENT GENERAL SUPPORT MAINTENENCE", WHICH IS WHAT WE DID. EGSM stands for Extended Global System for Mobile communication . This is introduced to enhance the capacity of the network, i.e., to accomodate more number of mobile subscribers .
How many channels are present in GSM 900?
174 no ........ the uplink is 890-915 & down link is 935-960.....MHz each channel having band width of 200KHz & using by 8 subsciber.... so 25MHz/200Khz ......=125...so there are 125 channels present in GSM900 but one channel is use as a guard so only 124 channel present in GSM900
Is razr is gsm phone?
RAZR WILL WORK WITH BOTH GSM & IDEN THE PROGRAMING MAKES THE DIFFERANCE
Does Vodafone have CDMA or GSM facility?
The Vodafone group operates in 16 different countries in Europe. Vodafone-Germany operates both GSM and UMTS (W-CDMA) networks
What are the merits and demerits of GSM?
Advantages of 2G GSM * GSM is mature; this maturity means a more stable network with robust features. * Less signal deterioration inside buildings. * Ability to use repeaters. * Talktime is generally higher in GSM phones due to the pulse nature of transmission. * The availability of Subscriber Identity Modules allows users to switch networks and handsets at will. * GSM covers virtually all parts of the world so international roaming is not a problem. [edit] Disadvantages of 2G GSM * Pulse nature of TDMA transmission used in 2G interferes with some electronics, especially certain audio amplifiers. 3G uses W-CDMA now. * Intellectual property is concentrated among a few industry participants, creating barriers to entry for new entrants and limiting competition among phone manufacturers. * GSM has a fixed maximum cell site range of 35 km, which is imposed by technical limitations.
What is gsm uplink?
Hi, For every GSM band there are Uplink and downlink frequencies. Example: GSM 900 TX: 880 MHz to 915 MHz is an uplink frequency range GSM 900 RX: 925 MHz to 960 MHz is a downlink frequency range Aloha, Maverick
What is uplink frequency in gsm?
GSM 900: Uplink frequency: 890 - 915 MHz GSM 1800 : Uplink frequency: 1710 - 1785 MHz GSM 1900: Uplink frequency: 1850 - 1910 MHz
Frequency band of uplink in GSM?
1800mhz
Why is the gsm 900 better than gsm 1800 and gsm 1900?
As the frequency increase its penetration power decreases.The signal travels a lesser distance.Hence for a perticular area more no of towers need to be erected in 1800/1900 than in 900MHZ for full coverage...Hence vodafone( 1800MHZ) has more towers per unit area than Idea Cellular ( 1800+900) ..... Band of 900 is from 890-915( uplink) 935-960Mhz( downlink).... Band of 1800 is from 1710-1785(uplink) and 1805-1880MHZ(Downlink).... Same property is followed here.....The uplink is lower ( MOBILE -BTS) than the downlink frequency (BTS-MOBILE)...so that this may help the uplink signal to travel futher without consuming much power...BTS due to its increased power ,has higher frequency to tavel the same distance....
Why gsm 880 mhz to 915 mhz is known as downlink frequency?
This is actually the EGSM uplink band. It carries signals "up" from the mobile station to the base station. EGSM downlink is from 925MHz to 960MHz and carries signals from the base station "down" to the mobile station.
What is upink frequecy in GSM?
It varies - according to which system is in use. The related link to Wikipedia lists the uplink & downlink frequencies.
Why does GSM use separate channels for Uplink and Downlink?
So that they can both be used at the same time (i.e. full duplex) without interference.
Gsm 900 vs gsm 1800?
GSM-900 and GSM-1800 are used in most parts of the world: Europe, Middle East, Africa, Australia and most of Asia. In South and Central America the following countries use the following: : :* Costa Rica - GSM-1800 :* Brazil - GSM-850, 900 and 1800 :* Guatemala - GSM-850, GSM-900 and 1900 :* El Salvador - GSM-850, GSM-900 and 1900 GSM-900 uses 890-915 MHz to send information from the mobile station to the base station (uplink) and 935-960 MHz for the other direction (downlink), providing 124 RF channels (channel numbers 1 to 124) spaced at 200 kHz. Duplex spacing of 45 MHz is used. Guard bands 100 kHz wide are placed at either end of the range of frequencies[1]. : In some countries the GSM-900 band has been extended to cover a larger frequency range. This 'extended GSM', E-GSM, uses 880-915 MHz (uplink) and 925-960 MHz (downlink), adding 50 channels (channel numbers 975 to 1023 and 0) to the original GSM-900 band. The GSM specifications also describe 'railways GSM', GSM-R, which uses 876-915 MHz (uplink) and 921-960 MHz (downlink). Channel numbers 955 to 1023. GSM-R provides additional channels and specialized services for use by railway personnel. : All these variants are included in the GSM-900 specification. GSM-1800 uses 1710-1785 MHz to send information from the mobile station to the base tranceiver station (uplink) and 1805-1880 MHz for the other direction (downlink), providing 374 channels (channel numbers 512 to 885). Duplex spacing is 95 MHz. : GSM-1800 is also called DCS (Digital Cellular Service) in the United Kingdom, while being called PCS in Hong Kong[2] (not to mix up with GSM-1900 which is commonly called PCS in the rest of the world.)
Are gsm use sfh to improve signal?
Frequency Hopping is an old technique introduced firstly in military transmission system to ensure the secrecy of communications and combat jamming. Frequency Hopping is mechanism in which the system changes the frequency (uplink and downlink) during transmission at regular intervals. It allows the RF channel used for signaling channel (SDCCH) timeslot or traffic channel (TCH) timeslots, to change frequency every TDMA frame (4.615 ms). The frequency is changed on a per burst basis, which means that all the bits in a burst are transmitted in the same frequency.
How do you convert cellphone gsm frequency to another gsm frequency?
How do you convert cellphone gsm frequency to another gsm frequency?"
What is the operating frequency of cellular communication?
There are two main types of Cellular phone com usage, that being CMDA and GSM. GSM operates, typically in a range of 850mhz, 900mhz, 1800 and 1900mhz. In parts of Europe it also uses 2100mhz. Older GMS specs can go as low as 380mhz for uplink and downlink and the channel will vary. CDMA operates at usually at 800mhz or 1900mhz. Some of the 4g WiMax signals can run as high as 2.7ghz. That however is used for data, not for voice mode. Again, different variations of this will run at other speeds but those are the most common ones.
What is frequency used by GSM antenna?
1.25MHz
