First Generation NetworkMuhammad Uzair Rasheed 2009-CPE-03 UCE&T BZU MULTAN
First Generation What we will look at 1st Generation technology Frequency Division Handover Infrastructure
First Generation Early Wireless communications Signal fires Morse Code Radio Radio Transmitter 1928 Dorchester
First Generation 1st Generation devices Introduced in the UK by Vodafone January 1985 UK Technology (and Italy) Total Access Cellular System This was based on the American design Used the 900MHz frequency range Europe Germany adopted C-net France adopted Nordic Mobile Telephone (NMT)
First Generation Operates Frequency Division Multiple Access (FDMA) Covered in next slide Operates in the 900MHz frequency range Three parts to the communications Voice channels Paging Channels Control Channels
1G technology FDMA Breaks up the available frequency into channels Allocates a single channel to each phone call The channel is agreed with the Base station before transmission takes place on agreed and reserved channel The device can then transmit on this channel No other device can share this channel even if the person is not talking at the time! A different channel is required to receive The voice/sound is transmitted as analog data.
Continued…. FDMA You use this technology all of the time! Consider your radio in the house(well use too!!!) As you want different information you change the frequency which you are receiving
Voice calls.. Are transferred using Frequency modulation The rate at which the carrier wave propogates is changed Encoding information More resistant to interference than AM radio (www.tiscali.co.uk/reference/encyclopaedia/hutchinson/m0030280.html, 2004)
First Generation Infrastructure Base Station Carries out the actual radio communications with the device Sends out paging and control signals MSC Takes responsibility Controls all calls attached to this device Maintains billing information Switches calls (Handover/hand off)
First Generation Cellular Architecture Allows the area to be broken into smaller cells The mobile device then connects to the closest cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell Cell
First Generation Cellular Architecture continued Cellular architecture requires the available frequency to be distributed between the cells If 2 cells next to each other used the same frequency each would interfere with each other Cell Cell Cell Cell Frequency 900 Cell
First Generation Cellular Architecture continued There must be a frequency difference between adjoining cells. Cell Frequency 900 Cell Frequency 920 Cell Cell Cell Cell Frequency 940 Cell Cell Frequency 960
First Generation Logically we picture a cell as being a Octagon In reality the shape of a transmission will change depending on the environment In this diagram of a cell you can see this The building are the rectangles in dark green The darker the shade of green the stronger the signal Cell Cell Cell Cell Cell
First Generation Cellular infrastructure why ?? Cells with different frequencies allow devices to move between these cells The device just informing what frequency they are communicating at. Cellular communications can only travel a certain distance Cell sizes are flexible Examples in the AMP system were up to 50 Miles!
First Generation Cellular infrastructure Once you get to the ‘edge’ of a cell you will need a handover Handover allows the user to move between cells After a certain distance the area covered by a certain cell ends so it switches over to the domain of the next cell.
Cellular infrastructure Communicating with BS1 Moving towards BS2 Tnm rasis snS ioB2 SBosm n i nT is s ar 1 BS1BS2
First Generation Cellular infrastructure Power of signal now weakening BS1BS2
First Generation Cellular infrastructure Paging signal stronger so hand over to new MSC BS1BS2
First Generation Handover Once a handover is decided upon by the BS The MSC is informed All BS in the area of the current location are informed to start paging the device The BS with the strongest signal is then handed over to The call can continue In reality a lot of calls were dropped whilst waiting for a handover to take place Ending a call The phone returns to an idle state and pagging ends
First Generation Problems Roaming was not applicable All of Europe was using different standards Different frequencies Different frequency spacing Security Calls were easily ‘listened’ upon Limited capacity of the available spectrum Analog signal meant a larger than required amount of the frequency had to be allocated to each call Expansion of the network was difficult This was unacceptable GSM was introduced….
Summary 1G systems Frequency Used Infrastructure Handover Problems Jazak Allah!!!!