Efficiency of TDMA system

The efficiency of a full form of a TDMA  system is a measure of the percentage of the data that is transmitted. In this system, the transmitted data has information for providing overhead for the access scheme.

We can measure the frame efficiency of TDMA is a percentage of bits per frame that contain transmitted data.

So the number of overhead bits per frame is expressed as in this form : 

overhead  = Nr br + Nt bp + Nt bg + Nr bg 

Nr = Number of reference burst per frame
Nt = Number of  traffic burst per frame
br = Number of overhead bits per reference burst for system
bp = Number of overhead bits per preamble in each slot for system
bg = Number of an equivalent bit in each guard time interval for the system

So we have to calculate the total number of bits per frame (bT)  is :

bT  = Tf  R

Tf = Frame duration
R = Channel bit rate

The frame efficency is ( 1 - boverhead / bT ) * 100 %