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We have 2 types of modulation:
- Fixed modulation
- Adaptive modulation
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In Fixed modulation we set the microwave link to operated on specific modulation order
- For example 265 QAM
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In adaptive modulation we set and configure the microwave Link to operate on range of modulations
- For example minimum modulation will be 128 QAM and maximum modulation will be 1024 QAM
- In that case the link will change the modulation order according to the change happening in the channel condition.
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Channel condition means the power level and bot errors and signal to noise ratio.
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Important formula : as the channel condition become better, the modulation can reach the maximum.
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In case the channel condition become worse, the Link will downgrade the modulation to recover the data.
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As modulation order increasing, the data rate increasing and the bot errors also increasing
- And vice versa
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We have to use adaptive modulation with Ethernet traffic and fixed modulation with SDH PDH traffic
Credits: