Chapter 3   

Technical Efficiency of Spectrum Utilisation 

3.1 

Definition of Spectrum Utilisation Efficiency 

3.1.1  ITU definition of Spectrum Utilisation Efficiency 

ITU R Recommendations SM.1046 1 on  

DEFINITION OF SPECTRUM USE AND 

EFFICIENCY OF A RADIO SYSTEM

  mentions 

 Efficient use of spectrum is achieved by (among other things) the isolation 

obtained from antenna directivity, geographical spacing, frequency sharing, or 

orthogonal frequency use and time sharing or time division and these 

considerations reflected in definition of spectrum utilization. Therefore, the 

measure of spectrum utilization   spectrum utilization factor, U, is defined to 

be the product of the frequency bandwidth, the geometric (geographic) space, 

and the time denied to other potential users: 

U  =  B     S     T 

where: 

B

: frequency 

bandwidth 

S

:  geometric space (usually area) and 

T

: time. . 

Also, the recommendation mentions 

 According to the definition of SUE (or spectrum efficiency as a shortened 

term) of a radiocommunication system, it can be expressed by: 

M

M

SUE  =  U  =  B     S     T (2) 

where: 

M

: 

amount of information transferred over a distance  

For cellular mobile systems, it can be expressed as 

(Traffic in Erlangs) 

SUE   =     (Amount of Spectrum in MHz) X (Area in Sq. Kms) 

For a 

specified 

GoS 

The time factor can be taken as 1 as the system operates continuously.  

This definition takes into account the traffic carrying capacity of a technology 

per MHz and the capability of the technology to replicate the available 

spectrum in the unit area for a specified Quality of Service. However, it does 

not take into account the cost involved in the implementation of individual 

technologies, and hence does not take into account any economic aspect of 

spectrum utilisation. Also, this definition presupposes that all the required QoS 

parameters are met at all times.  

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