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Spectral efficiency


Spectral efficiency of a point to point connection
Number of bits transported within a second and within a given bandwidth
Measured as bit/s/Hz
Increase by:
- Source coding e.g. Digital: MP3, Analog: Compander
- High order modulation e.g. 256 QAM
- MIMO multi antenna systems

Spectral efficiency of a wireless communication system
Number of bits transported within a second and within a given bandwidth summed over all users normalized to area
Measured as bit/s/Hz/km2
Increase by smaller cells, more dense placing of basestations

Efficiency of spectrum use, sometimes also called short “spectral efficiency”
Number of bits transported within a second and within a given summed over all users normalized to area
Measured as: bit/s/Hz/km2 across all systems
Increase by implementation of co-primary and secondary systems, that make use of resources actually not in use by primary systems, opportunistic access

(Source: Prof. Dr. rer.nat. Friedrich K. Jondral)

Spectral efficiency of PMSE

Spectrum efficiency with regards to PMSE can sometimes be interpreted differently:

1) The number of bits transported within a second and within a given bandwidth Measured as bit/s/Hz
Because of the very high quality and very low delay requirements for the operation of PMSE at the front-end of content and event production, the possible effect of source coding (compression) is limited. International documents also note that analogue audio PMSE devices already have source compression by means of their internal audio-companding systems. Therefore, no Digital Dividend for current digital audio PMSE equipment.

2) The number of PMSE links that can be operated in temporarily available local spectrum as PMSE/MHz
The document ' Four steps to understanding PMSE' splits the operation of audio PMSE in two basic methods
- Guaranteed intermodulation-free frequencies – the standard situation
- Linear frequency distribution