Synchronizing devices in a wireless communication network

1. A method for operating a base station of a wireless communication network, the base station comprising an antenna array having a plurality of antennas configured to communicate wirelessly with terminal devices positioned within a coverage area of the base station, a spatial transmission characteristic of the antenna array being configurable by applying precoding information, the method comprising:

determining the precoding information for concentrating a radio frequency power of a transmitted radio frequency signal to a group of terminal devices arranged in a sub area of the coverage area of the base station,

applying the determined precoding information to the antenna array,

transmitting, from the base station to the group of terminal devices, a synchronization signal using the precoding information,

receiving time interval information from at least one terminal device of the group of terminal devices, the time interval information indicating a required maximum time interval for synchronizing the at least one terminal device, and

determining schedule information indicating a schedule for transmitting the synchronization signal using the precoding information.

2. The method according to claim 1 , wherein determining the precoding information comprises at least one of:

determining the precoding information based on corresponding position information of each terminal device of the group of terminal devices,

determining the precoding information based on corresponding previous precoding information, which has been used during previous communications between the base station and each terminal device of the group of terminal devices,

selecting the precoding information from a predefined set of precoding information based on a pilot signal received from a terminal device, wherein the terminal device is assigned to the group of terminal devices, or

selecting the precoding information from a predefined set of precoding information based on a report received from a terminal device of the group of terminal device, wherein the report indicates which precoding information provides a synchronization signal having the strongest level in the sub area in which the corresponding terminal device resides.

3. The method according to claim 2 , wherein the position information comprises at least one of:

a geographical position of the terminal device,

a velocity of the terminal device, or

a moving direction of the terminal device.

4. The method according to claim 1 , further comprising:

transmitting the schedule information from the base station to the group of terminal devices.

5. The method according to claim 1 , further comprising:

acquiring, at a terminal device of the group of terminal devices, timing and/or frequency information of the base station based on the synchronization signal transmitted from the base station, and

transmitting a pilot signal from the terminal device to the base station based on the acquired timing and/or frequency information, the pilot signal being configured for a channel sounding of a radio frequency channel between the terminal device and base station for determining characteristics of the radio frequency channel.

6. The method according to claim 5 , further comprising:

receiving the pilot signal from the terminal device at the base station,

determining further precoding information based on the pilot signal received from the terminal device,

applying the further precoding information to the antenna array, and

transmitting, from the base station to the terminal device, the synchronization signal using the further precoding information.

7. The method according to claim 6 , further comprising:

receiving, from the terminal device, time interval information, the time interval information indicating a required maximum time interval for synchronizing the terminal device, and

determining further schedule information indicating a schedule for transmitting the synchronization signal using the further precoding information.

8. The method according to claim 7 , further comprising:

transmitting the further schedule information from the base station to the terminal device.

9. The method according to claim 1 corresponding transceiver is assigned, wherein applying the precoding information comprises at least one of:

applying to each transceiver corresponding gain information provided by the precoding information, or

applying to each transceiver corresponding phase information provided by the precoding information.

10. The method according to claim 1 , wherein the synchronization signal comprises a sequence of synchronization signals.

11. A base station, comprising:

an antenna array having a plurality of antennas configured to communicate wirelessly with terminal devices positioned within a coverage area of the base station, a spatial transmission characteristic of the antenna array being configurable by applying precoding information, and

a control unit configured

to determine precoding information for concentrating a radio frequency power of a transmitted radio frequency signal to a group of terminal devices arranged in a sub area of the coverage area of the base station,

to apply the determined precoding information to the antenna array,

to transmit a synchronization signal using the precoding information,

to receive time interval information from at least one terminal device of the group of terminal devices, the time interval information indicating a required maximum time interval for synchronizing the at least one terminal device, and

to determine schedule information indicating a schedule for transmitting the synchronization signal using the precoding information.

12. A terminal device, comprising

at least one antenna configured to wirelessly communicate with a base station of a wireless communication network,

a synchronization control unit configured

to receive a sequence of synchronization signals from the base station,

to acquire timing and/or frequency information of the base station based on the synchronization signals, and

to transmit time interval information to the base station, the time interval information indicating a required maximum time interval for synchronizing the terminal device.

13. The terminal device according to claim 12 , wherein the synchronization control unit is configured

to receive schedule information from the base station, and

to automatically change from an inactive state into an active state based on the received schedule information.