High modulation, a key differentiator for microwave

High modulation, a key differentiator for microwave

There are several features today such as RF performance and capacity that allow each microwave vendors to develop those weapons to attack macro and small cell networks as operators densify their networks following initial LTE deployments.

High modulation is the key component in enabling high capacity and to eventually delivering Gbps scale microwave capacity in combination with multiplexing techniques as XPIC (Cross Polarization Interference Cancellation). 4096QAM (Quadrature Amplitude Modulation) is today the most advanced modulation technology for microwave communications and improves efficiency by as much as 55 percent over the widely implemented 256QAM. The same time, it sets the capacity and performance stage towards 5G.

Superior system gain is also one of the key parameters for microwave. The data transmission per symbol for the 4096 QAM modulation method is 12 bits/symbol, making it more highly efficient than the 8-bits/symbol of the current widespread 256QAM modulation method. These higher-order modulation levels have been implemented through advances in  radio design technologies that have reduced equipment-generated noise and signal distortion. As modulation gets higher, the receiver sensitivity is reduced by 3 dB for every increased step, while the related capacity gain gets smaller (in percentage terms).

Although we are approaching the modulation’s theoretical and practical limits, it is a very desirable feature since the higher modulation the higher increase of the potential capacity by coding bits on to each symbol.

Summarizing into a higher-order the 4096 modulation benefits:

  1. Higher capacity
  2. Increased sensitivity to noise and signal distortion.
  3. Superior system gain
  4. Link robustness

Are the vendors there yet? There are only few vendors that have already implemented 4096QAM and are ready to ship, Dragonwave and Intracom Telecom when others are rather planning to offer this feature in 2016.

Are operators interested into 4096QAM? The answer is yes (might even become mandatory in upcoming RFPs), it is of interest but it has to come with other functionality like 112MHz wide channels, possible for those operators managing their own spectrum but not an option yet for those dependant on regulator’s managed bands.

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