Resource-efficient beam selection in 5G and 6G
Communications in 5G and 6G can use “beams” to focus electromagnetic energy on the recipient, and the recipient can likewise arrange a focused reception “beam” toward the transmitter, thereby saving energy and avoiding interference. However, aligning the transmission and reception beams remains an arduous process. Herein, procedures are disclosed for rapid and efficient beam alignment at both transmission and reception devices, using very brief response signals to select an optimal beam direction for best signal quality. By encoding the selected beam index in the time, frequency, and optionally modulation of the brief signal, the transmitter and receiver can cooperate to optimize communication and save energy.
1. A method for a base station of a wireless network to align a beam from the base station to a user device of the network, the method comprising:
a. transmitting a plurality of beam scan signals, each beam scan signal comprising a wireless transmission focused in a different direction, the beam scan signals spaced apart in time or in frequency;
b. receiving, from the user device, a reply signal indicating a particular beam scan signal, the reply message comprising a wireless transmission at a time corresponding to a time of the particular beam scan signal or at a frequency corresponding to a frequency of the particular beam scan signal; and
c. transmitting, to the user device, a subsequent message directed according to the particular beam scan signal;
d. wherein the subsequent message comprises an alignment message comprising a plurality of alignment message elements, wherein all of the alignment message elements are transmitted with the same amplitude, phase, and spatial distribution.
2. The method of claim 1 , wherein the beam scan signals are transmitted according to at least 5G technology.
3. The method of claim 1 , wherein the particular beam scan signal provides higher signal quality than any other beam scan signal, wherein signal quality comprises a received amplitude or a received power level or a received signal-to-noise ratio at the user device.
4. The method of claim 1 , wherein each beam scan signal comprises exactly one resource element, and the reply signal comprises exactly one resource element.
5. The method of claim 1 , wherein each beam scan signal comprises two resource elements configured as a demodulation reference, and the reply signal comprises a channel-state information message.
6. The method of claim 1 , wherein the beam scan signals are spaced apart in time, and the reply signal is received at a predetermined delay time after the particular beam scan signal.
7. The method of claim 1 , wherein the beam scan signals are spaced apart in frequency, and the reply signal is received at the same frequency as the particular beam scan signal.
8. The method of claim 1 , further comprising indicating, to the user device, a reply window comprising a plurality of resource elements, and receiving the reply signal within the reply window.
9. The method of claim 1 , wherein the beam scan signals are spaced apart in frequency and the alignment message elements are spaced apart in time.