Network initiated reselection of transmitter and receiver configurations
A network initiated procedure is introduced for updating an SS-BPL once the gNB TX beam and wireless device RX beam start to become misaligned due to movement/rotation of the wireless device. When the gNB measures and determines that a re-establishment of the SS-BPL should be performed, the gNB transmits a trigger signal to the wireless device to update the SS-BPL. In one embodiment, the trigger signal may initiate a new SS block measurement by the wireless device, and a transmission of an uplink signal (e.g., a PRACH transmission) to indicate to the gNB the new preferred SS block and thus a new SS-BPL. In another embodiment, the gNB determines a new SS block for the wireless device and indicates directly in a message from gNB to wireless device an SS block selected by the gNB to use for SS-BPL in subsequent transmissions.
1. A method implemented by a network node in a wireless communication network, the method comprising the network node:
selecting, based on a spatial quasi co-location (QCL) assumption, an initial transmitter configuration for transmitting downlink data signals to a wireless device by:
sending two or more downlink synchronization signals to the wireless device in different spatial directions;
receiving a random access signal from the wireless device on a random access channel, the random access signal indicating a preferred downlink synchronization signal; and
selecting the initial transmitter configuration based on the preferred downlink synchronization signal;
determining a quality of an uplink signal received from the wireless device; and
based on the quality of the uplink signal, initiating a reselection procedure to select a new transmitter configuration for transmitting the downlink data signals in accordance with further spatial QCL assumption.
2. The method of claim 1 , wherein the selecting the initial transmitter configuration based on the preferred downlink synchronization signal comprises selecting the initial transmitter configuration for transmitting the downlink data signals so that the transmission of the downlink data signals is quasi co-located with the transmission of the preferred synchronization signal.
3. The method of claim 1 :
wherein the initiating the reselection procedure comprises sending a trigger signal to the wireless device;
further comprising:
receiving, responsive to the trigger signal, a reselection signal from the wireless device, the reselection signal indicating a new preferred downlink synchronization signal; and
selecting the new transmitter configuration for transmitting based on the new preferred downlink synchronization signal.
4. The method of claim 3 , wherein the reselection signal comprises a random access signal transmitted by the wireless device on a random access channel.
5. The method of claim 3 , wherein the selecting the new transmitter configuration based on the new preferred downlink synchronization signal comprises selecting the initial transmitter configuration for transmitting the downlink data signal so that the transmissions of the downlink data signals are quasi co-located with the transmission of the new preferred synchronization signal.
6. The method of claim 1 , further comprising:
measuring uplink reference signals transmitted by the wireless device on an uplink channel; and
selecting a new transmitter configuration based on the measurements of the uplink reference signals.
7. A network node in a wireless communication network comprising:
interface circuitry configured to transmit signals to, and receive signals from, a wireless device served by the network node; and
processing circuitry configured to:
select, based on a spatial quasi co-location (QCL) assumption, an initial transmitter configuration for transmitting downlink data signals to the wireless device by:
sending two or more downlink synchronization signals to the wireless device in different spatial directions;
receiving a random access signal from the wireless device on a random access channel, the random access signal indicating a preferred downlink synchronization signal; and
selecting the initial transmitter configuration based on the preferred downlink synchronization signal;
determine a quality of an uplink signal received from the wireless device; and
based on the quality of the uplink signal, initiate a reselection procedure to select a new transmitter configuration for transmitting the downlink data signals in accordance with a further spatial QCL assumption.
8. A non-transitory computer readable recording medium storing a computer program product for controlling a network node in a wireless communication network, the computer program product comprising software instructions which, when run on processing circuitry of the network node, causes the network node to:
select, based on a spatial quasi co-location (QCL) assumption, an initial transmitter configuration for transmitting downlink data signals to a wireless device by:
sending two or more downlink synchronization signals to the wireless device in different spatial directions;
receiving a random access signal from the wireless device on a random access channel, the random access signal indicating a preferred downlink synchronization signal; and
selecting the initial transmitter configuration based on the preferred downlink synchronization signal;
determine a quality of an uplink signal received from the wireless device; and
based on the quality of the uplink signal, initiate a reselection procedure to select a new transmitter configuration for transmitting the downlink data signals in accordance with a further spatial QCL assumption.
9. A method implemented by a wireless device in a wireless communication network, the method comprising the wireless device:
selecting, based on a spatial quasi co-location (QCL) assumption, an initial receiver configuration for receiving downlink data signals from a network node by:
receiving, at the wireless device, two or more downlink synchronization signals transmitted by the network node in different spatial directions;
selecting a preferred one of the downlink synchronization signals;
selecting the initial receiver configuration based on the preferred downlink synchronization signal; and
sending a random access signal to the network node on a random access channel, the random access signal indicating the preferred synchronization signal;
receiving a trigger signal from the network node; and
responsive to the trigger signal, executing a reselection procedure to select a new receiver configuration for receiving the downlink data signals based on a further spatial QCL assumption.
10. The method of claim 9 , wherein the selecting the initial receiver configuration based on the preferred downlink synchronization signal comprises selecting the initial receiver configuration for receiving the downlink data signals based on the QCL assumption that the transmissions of the downlink data signals are quasi co-located with the transmission of the preferred synchronization signal.
11. The method of claim 9 , further comprising, responsive to the trigger signal:
detecting a new preferred one of two downlink synchronization signals transmitted by the network node in different spatial directions; and
selecting a new receiver configuration for receiving the downlink data signals from the network node based on the spatial QCL assumption that the transmissions of the downlink data signals are quasi co-located with the transmission of the new preferred downlink synchronization signal.
12. The method of claim 9 , further comprising, responsive to the trigger signal:
receiving an indication of a new preferred downlink synchronization signal from the network node;
detecting the preferred downlink synchronization signal indicated by the network node; and
selecting the new receiver configuration for receiving the downlink data signals from the network node based on the spatial QCL assumption that the transmissions of the downlink data signals are quasi co-located with the transmission of the new preferred downlink synchronization signal.
13. The method of claim 9 , wherein the selecting the initial receiver configuration and selecting the new receiver configuration comprise selecting beamforming weights used to generate a receive beam for receiving the downlink data signals.
14. A wireless device in a wireless communication network comprising:
interface circuitry for transmitting signals to and receiving signals from a network node; and
processing circuitry configured such that the wireless device is operative to:
select, based on a spatial quasi co-location (QCL) assumption, an initial receiver configuration for receiving downlink data signals from a network node by:
receiving, at the wireless device, two or more downlink synchronization signals transmitted by the network node in different spatial directions;
selecting a preferred one of the downlink synchronization signals;
selecting the initial receiver configuration based on the preferred downlink synchronization signal; and
sending a random access signal to the network node on a random access channel, the random access signal indicating the preferred synchronization signal;
receive a trigger signal from the network node; and
responsive to the trigger signal, execute a reselection procedure to select a new receiver configuration for receiving the downlink data signals based on a further spatial QCL assumption.
15. A non-transitory computer readable recording medium storing a computer program product for controlling a wireless device in a wireless communication network, the computer program product comprising software instructions which, when run on processing circuitry of the wireless device, causes the wireless device to:
select, based on a spatial quasi co-location (QCL) assumption, an initial receiver configuration for receiving downlink data signals from a network node by:
receiving, at the wireless device, two or more downlink synchronization signals transmitted by the network node in different spatial directions;
selecting a preferred one of the downlink synchronization signals;
selecting the initial receiver configuration based on the preferred downlink synchronization signal; and
sending a random access signal to the network node on a random access channel, the random access signal indicating the preferred synchronization signal;
receive a trigger signal from the network node; and
responsive to the trigger signal, execute a reselection procedure to select a new receiver configuration for receiving the downlink data signals based on a further spatial QCL assumption.