Method of adjusting the length of a data block in a time-division multiple access communication system
AssigneeAlcatel
InventorsChristophe Mourot, Vinod Kumar, Jean-Claude Dany, Armelle Wautier
Life of this patent
Estimating the term…
Abstract
A method for adjusting the length of a data block in a time-division multiple access communication system includes estimating the impulse response of a communication channel from received symbols of a reference sequence, estimating a signal-to-noise ratio from the channel impulse response, and estimating a maximum Doppler shift. Using these estimations, upper and lower limit functions of a normalized estimated mean squared error are calculated, and the length of the data block is adjusted to an optimal length determined from the upper and lower limit functions.
Claims7
A method of adjusting the length of a data block (BD) in accordance with time-varying behavior of a communication channel, the data block being transmitted as a signal on the time-varying communication channel of a time-division multiple access (TDMA) communication system, the signal being received at a receiver, said data block (BD) comprising:
- a training sequence (SA) including a reference sequence (SR) of length P;
- and a data sequence (D) of length n.sub.s containing data symbols having a symbol interval (T.sub.s), said communication channel having an impulse response of finite length K, the method comprising the steps of:
- estimating the impulse response of the communication channel from received symbols of the reference sequence (SR);
- estimating a signal-to-noise ratio from the channel impulse response;
- estimating a maximum doppler shift of the signal at the receiver;
- calculating, from the signal-to-noise ratio, the doppler shift, the length K of the impulse response, the length P of the reference sequence (SR) and the symbol interval (T.sub.s), lower and upper limit functions of normalized estimate mean squared error (E.sub.min (n.sub.s), E.sub.max (n.sub.s)) as a function of the length n.sub.s of the data sequence (D);
- determining a range for an optimal length of the data sequence (D) from the upper and lower limit functions and from a predetermined range of mean squared error which is acceptable in the communication system;
- and
- adjusting the length n.sub.s of the data sequence (D) to a length n.sub.opt which lies within said range for an optimal length of the data sequence.
Dependencies are inferred from the claim text.