Method for channel estimation when using different modulation methods within one signal interval
View Patent ↗The method is based on a signal interval (DB) which comprises a first part (ET) (which is modulated using a first modulation method (GFSK)) of the signal interval and a second part (which is modulated using a second modulation method (DMPSK)) of the signal interval. The channel parameters (c(i)) relating to the second part (which is modulated using the second modulation method) of the signal interval are determined using a received data signal (a(i); p(i)) from the first part (ET) of the signal interval (DB).
1. A method for determination of channel parameters in a mobile radio receiver relating to a second part of a signal interval, with the signal interval comprising a first part which is modulated using a first modulation method and a second part which is modulated using a second modulation method, with the first part and the second part being filtered using different pulse shapes, the method comprising:
estimating channel parameters relating to the first part of the signal interval from the first part of the signal interval, and
determining the channel parameters relating to the second part of the signal interval from the channel parameters relating to the first part of the signal interval, further comprising:
applying the pulse-shape of the first part of the signal interval to determine the channel parameters relating to the second part of the signal interval independent of the modulation-dependent pulse shaping of the first part, and
using the pulse-shape of the second part of the signal interval to determine the channel parameters relating to the second part of the signal interval from the channel parameters relating to the first part of the signal interval.
2. The method according to claim 1 , wherein the signal interval corresponds to a data burst.
3. The method according to claim 2 , wherein the first part of the data burst comprises an access code and a first header, and the second part of the data burst comprises a training sequence.
4. The method according to claim 3 , wherein the channel parameters relating to the first part of the data burst are estimated by a MMSE estimation method using the received data signal from the first part of the data burst and reference information which is associated with this data signal.
5. The method according to claim 3 , wherein the channel parameters relating to the first part of the data burst are estimated by a MAP-LMMSE estimation method using the received data signal from the first part of the data burst and reference information which is associated with this data signal.
6. The method according to claim 4 , wherein the reference information and/or, depending on this, a plurality of results of the computation operations of the MMSE estimation method are stored in the receiver at a factory.
7. The method according to claim 5 , wherein the reference information and/or, depending on this, a plurality of results of the computation operations of the LMMSE estimation method are stored in the receiver at a factory.
8. The method according to claim 3 , wherein the channel parameters relating to the first part of the data burst are estimated with the aid of an iterative LMS estimation method using the received data signal from the first part of the data burst and reference information which is associated with this data signal.
9. The method according to claim 4 , further comprising:
determining a modulation-dependent reference signal as reference information by pulse-shaping of a modulation-independent reference sequence using the first modulation method.
10. The method according to claim 3 , further comprising:
determining additional channel parameters relating to the second part of the data burst which is modulated using the second modulation method from the training sequence of the received data signal and reference information which is associated with this data signal.
11. The method according to claim 10 , wherein the determination of the channel parameters relating to the second part of the data burst is carried out using the additional channel parameters.
12. The method according to claim 11 , wherein the channel parameters relating to the second part of the data burst are determined as a function of a selection variable, which is dependent on the respective connection,
as resultant channel parameters relating to the first part of the data burst which are obtained from a transmission-end pulse-shaping using the second modulation method of the determined channel parameters relating to the first part of the data burst, or
as additional channel parameters relating to the second part of the data burst, with these additional channel parameters taking account of the transmission-end pulse-shaping in the second modulation method, or
as averaging of the individual resultant channel parameters and of the individual additional channel parameters, in which case these take account of the transmission-end pulse-shaping in the second modulation method.
13. The method according to claim 1 , wherein the first modulation method is GFSK modulation, and the second modulation method is DMPSK modulation with M≧4.
14. The method according to claim 12 , wherein the method comprises:
determination of a modulation index of a GFSK modulation, wherein the selection variable is the modulation index.
15. The method according to claim 1 , wherein the method is used in a Bluetooth transmission system based on a Bluetooth Standard Version 1.2 or higher.
16. A method for determination of channel parameters in a mobile radio receiver relating to a second part of a data burst, with the data burst comprising a first part which is modulated using a first modulation method and a second part which is modulated using a second modulation method, the method comprising:
determining a modulation-dependent reference signal by pulse-shaping of a modulation-independent reference sequence using the first modulation method,
determining channel parameters relating to the first part of the data burst from the received data signal of the first part of the data burst and from the modulation-dependent reference signal, with these channel parameters describing only the modulation-independent part of the channel, and
determining the channel parameters relating to the second part of the data burst from the channel parameters relating to the first part of the data burst and from the pulse shape of the second part of the signal interval.
17. The method according to claim 16 , wherein the first part of the data burst comprises an access code and a first header, and the second part of the data burst comprises a training sequence.
18. The method according to claim 17 , wherein the channel parameters relating to the first part of the data burst are estimated with the aid of an MMSE estimation method using the received data signal from the first part of the data burst and reference information which is associated with this data signal.
19. A method for determination of channel parameters in a mobile radio receiver relating to a second part of a signal interval, with the signal interval having a first part which is modulated using a first modulation method of the signal interval and a second part which is modulated using a second modulation method of the signal interval, the method comprising:
estimating channel parameters relating to the first part of the signal interval from the first part and by applying the pulse-shape of the first part so that the estimated channel parameters relating to the first part of the signal interval only describe the modulation-independent part of the channel, and
estimating the channel parameters relating to the second part of the signal interval which is modulated using the second modulation method from the estimated channel parameters relating to the first part of the signal interval and by using the modulation-dependent pulse-shape of the second part of the signal interval.
20. The method according to claim 1 , wherein the channel parameters relating to the second part of the signal interval also describe the modulation-dependent part of the channel.
21. The method according to claim 19 , wherein estimating the channel parameters relating to the first part of the signal interval comprises
convoluting or filtering a modulation-independent reference sequence associated with the first part of the signal interval by a pulse shape of the first modulation method to generate a modulation-dependent reference signal, and
estimating the channel parameters relating to the first part of the signal interval from the first part and the modulation-dependent reference signal.
22. The method according to claim 19 , wherein estimating the channel parameters relating to the second part of the signal interval comprises
convoluting or filtering the channel parameters relating to the first part of the signal interval by a pulse shape of the second modulation method.