26-07-2012, 04:13 PM
First Generation
[attachment=29128]
1st Generation devices
Introduced in the UK by Vodafone
January 1985
UK Technology (and Italy)
Total Access Cellular System (TACS)
This was based on the American design of AMPS
Used the 900MHz frequency range
Europe
Germany adopted C-net
France adopted Nordic Mobile Telephone (NMT)
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
PCS – 1G to 2G technology
FDMA
Breaks up the available frequency into 30 KHz 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 analogue data, which means that a large than required channel has to be allocated.
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)
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
Radio Planning
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
[attachment=29128]
1st Generation devices
Introduced in the UK by Vodafone
January 1985
UK Technology (and Italy)
Total Access Cellular System (TACS)
This was based on the American design of AMPS
Used the 900MHz frequency range
Europe
Germany adopted C-net
France adopted Nordic Mobile Telephone (NMT)
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
PCS – 1G to 2G technology
FDMA
Breaks up the available frequency into 30 KHz 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 analogue data, which means that a large than required channel has to be allocated.
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)
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
Radio Planning
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