Positional determination of a user in a mobile communications system with emission diversity
View Patent ↗The invention relates to a method for increasing the precision during the determination of system parameters dependent on the propagation delay, e.g. for a positional determination, in a mobile communications system with emission diversity, according to which a subscriber data signal and a reference signal are assigned to a subscriber. The subscriber data signal is emitted by at least two antenna devices on the emission side, whereas the reference signal is emitted exclusively by one antenna device on the emission side. The reference signal is used to precisely determine signal propagation delays, upon which the system parameters depend.
1. A method for data transmission in a wireless communication system, comprising:
emitting a subscriber data signal assigned to a subscriber from at least two antenna devices using a diversity method;
emitting a reference signal assigned to the subscriber from only one of the at least two antenna devices; and
measuring propagation delay of the reference signal to determine runtime critical system parameters for a positional determination of the subscriber, wherein
the antenna device used to send the reference signal is switched between the at least two antenna devices
when the antenna device used to send the reference signal is switched, the propagation delay is compared for the at least two antenna devices, and
for future propagation delay measurements, the antenna device used to send the reference signal is selected to be the antenna device associated the smaller propagation delay.
2. The method according to claim 1 wherein when the antenna device used to send the reference signal is switched, a comparison is made, and
for future propagation delay measurements, the antenna device most closely within line-of-sight of the subscriber is selected.
3. The method according to claim 1 wherein the reference signal is selected from a plurality of manufacturer-specific reference signals, and
the manufacturer-specific reference signals are stored on a transmit side in a table.
4. The method according to claim 1 wherein the at least two antenna devices have polarizations orthogonal to one another.
5. The method according to claim 1 wherein the at least two antenna devices have the same polarization, but are at a fixed distance from one another.
6. The method according to claim 1 wherein the antenna device used to send the reference signal is switched between the at least two antenna devices.
7. The method according to claim 1 wherein the subscriber data signal and the reference signal are transmitted using a time division multiple access method.
8. The method according to claim 7 , wherein the reference signal is a training sequence transmitted in a time slot used for synchronization.
9. The method according to claim 8 , wherein the wireless communication system is a GSM mobile radio system, and an extended training sequence of a synchronization time slot is used as the reference signal.
10. The method according to claim 1 wherein the positional determination is performed with a timing advance mechanism.
11. The method according to claim 10 wherein the subscriber data signal and the reference signal are transmitted using a time division multiple access method.
12. The method according to claim 11 , wherein the reference signal is a training sequence transmitted in a time slot used for synchronization.
13. The method according to claim 12 , wherein the wireless communication system is a GSM mobile radio system, and an extended training sequence of a synchronization time slot is used as the reference signal.
14. The method according to claim 13 , wherein the reference signal is selected from a plurality of manufacturer-specific reference signals, and
the manufacturer-specific reference signals are stored on a transmit side in a table.
15. The method according to claim 14 , wherein the at least two antenna devices have polarizations orthogonal to one another.