Method of adjusting the length of a data block in a time-division multiple access communication system
First Claim
1. 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 ns containing data symbols having a symbol interval (Ts), 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 (Ts), lower and upper limit functions of normalized estimate mean squared error (Emin (ns), Emax (ns)) as a function of the length ns 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 ns of the data sequence (D) to a length nopt which lies within said range for an optimal length of the data sequence.
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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.
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Citations
7 Claims
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1. 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 ns containing data symbols having a symbol interval (Ts), 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 (Ts), lower and upper limit functions of normalized estimate mean squared error (Emin (ns), Emax (ns)) as a function of the length ns 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 ns of the data sequence (D) to a length nopt which lies within said range for an optimal length of the data sequence. - View Dependent Claims (2, 3, 4, 5, 6, 7)
- a training sequence (SA) including a reference sequence (SR) of length P; and
Specification