Resource-efficient low-complexity beamforming feedback in 5G/6G
View Patent ↗Feedback messages are essential for controlling transmission beams between network devices in 5G and 6G. Disclosed are brief signals and procedures for a user device to provide feedback to a base station on beam direction, transmission power, beam width, and other transmission parameters. The resource cost is so low, the base station can provide alignment test signals with each downlink message, and the user device can provide feedback selecting a best-received test signal as part of each uplink message, such as an acknowledgement. With such near-real-time beam fine-tuning, base stations and user devices can maintain the tight directional communications required for next-generation communications, without burdening the network with cumbersome feedback messages of prior art. Numerous other aspects are disclosed.
1. A method for a base station of a wireless network, the method comprising:
a) transmitting a leading demodulation reference, concatenated with a downlink message, concatenated with a following demodulation reference, each demodulation reference of the leading and following demodulation references modulated according to a maximum modulation level and a minimum modulation level of a modulation scheme;
b) wherein the downlink message is transmitted with a transmission parameter set to an initial value;
c) a “higher” demodulation reference, of the leading and following demodulation references, is transmitted with the transmission parameter set to a higher value than the initial value;
d) a “lower” demodulation reference, of the leading and following demodulation references, is transmitted with the transmission parameter set to a lower value than the initial value;
e) receiving, from a user device of the wireless network, a feedback message comprising a selection, the selection comprising either the leading demodulation reference, or the downlink message, or the following demodulation reference;
f) determining, by a processor in the base station, an adjusted value of the transmission parameter according to the selection; and
g) transmitting an acknowledgement to the user device with the transmission parameter set to the adjusted value;
h) wherein the transmission parameter comprises a polarization angle; and
i) wherein the determining the adjusted value comprises:
i) when the selection indicates the higher demodulation reference, setting the adjusted value equal to the initial value plus a predetermined increment;
k) when the selection indicates the lower demodulation reference, setting the adjusted value equal to the initial value minus the predetermined increment; and
l) When the selection indicates the downlink message, setting the adjusted value equal to the initial value.
2. The method of claim 1 , wherein the downlink message is transmitted according to 5G or 6G technology.
3. The method of claim 1 , wherein the transmission parameter comprises a transmission beam width.
4. The method of claim 1 , wherein the determining the adjusted value comprises:
a) when the selection indicates the higher demodulation reference, setting the adjusted value a) equal to the higher value;
b) when the selection indicates the lower demodulation reference, setting the adjusted value equal to the lower value; and
c) when the selection indicates the downlink message, setting the adjusted value equal to the initial value.
5. The method of claim 1 , further comprising:
a) determining, by the processor, that the transmission parameter has been increased twice in succession or decreased twice in succession, and responsively increasing the predetermined increment by a predetermined amount;
b) determining, by the processor, that the transmission parameter has been increased and then decreased in succession, or has been decreased and then increased in succession, and responsively decreasing the predetermined increment to a predetermined minimum size.
6. The method of claim 5 , further comprising:
a) determining, by the processor, that the adjusted value equals the initial value, and responsively decreasing the predetermined increment to the predetermined minimum size.
7. The method of claim 6 , further comprising:
a) determining, by the processor, that the transmission parameter is set to a value that was previously used for transmitting a previous downlink message or a previous demodulation reference, and responsively decreasing the predetermined increment to the predetermined minimum size.
8. The method of claim 7 , wherein the predetermined increment is increased or decreased before the transmission parameter is adjusted.
9. The method of claim 7 , wherein the transmission parameter is adjusted before the predetermined increment is increased or decreased.
10. The method of claim 1 , further comprising:
a) receiving, concatenated with the feedback message, two test signals; and
b) transmitting, concatenated with or multiplexed with the acknowledgement message, an indication indicating which item, of the feedback message and the two test signals, was received by the base station with a highest signal quality.