Low-complexity beam alignment by directional phase in 5G and 6G
View Patent ↗Beamforming is a critical element of 5G and especially 6G, but currently requires a series of time-consuming and resource-consuming messages. Disclosed are procedures by which base stations can transmit a phased beam pulse, having a phase that varies with angle, so that each user device can measure the received phase of the pulse and thereby determine its angle relative to the base station. Each user can then sequentially inform the base station of its orientation relative to the base station, or can append that information to another message such as an initial access message or an acknowledgement, for example. The user device and the base station can then exchange messages in narrow beams aimed at each other according to the alignment angle. Also disclosed are procedures to economically generate the wide-angle phased beam by combining overlapping beams of various phases.
1. A method for a first wireless entity to determine an alignment direction toward a second wireless entity, relative to the first wireless entity, the method comprising:
a) transmitting, by the first wireless entity, a first beam comprising a wide beam configured to span an angular range between a first angle and a second angle;
b) wherein the first beam comprises a first phase distribution which is modulated, at the first angle, according to a first phase value, and is modulated, at the second angle, according to a second phase value;
c) wherein the first phase distribution varies monotonically, from the first phase value to the second phase value, as the angle ranges from the first angle to the second angle;
d) receiving, from the second wireless entity, a reply message indicating a measured phase value, measured by the second wireless entity upon receiving the first beam; and
e) calculating, according to the first and second phase values and the first and second angles, and the measured phase value, the alignment direction toward the second wireless entity relative to the first wireless entity.
2. The method of claim 1 , wherein the first beam is transmitted according to 5G or 6G technology.
3. The method of claim 1 , wherein the reply message further indicates at least one of:
a) the alignment direction toward the first wireless entity from the second wireless entity; or
b) the alignment direction toward the second wireless entity from the first wireless entity.
4. The method of claim 3 , further comprising, when the reply message indicates the measured phase value of the first beam, as measured by the second wireless entity:
a) calculating the alignment direction toward the second wireless entity relative to the first wireless entity, wherein the calculating is based on:
i) a difference between the measured phase value and the first phase value;
ii) a difference between the first and second angles; and
iii) a difference between the first and second phase values.
5. The method of claim 4 , further comprising, after calculating the alignment direction toward the second wireless entity relative to the first wireless entity, then transmitting a unicast message to the second wireless entity indicating either:
a) the alignment direction toward the second wireless entity relative to the first wireless entity; or
b) the alignment direction toward the second wireless entity relative to the first wireless entity plus 180 degrees.
6. The method of claim 1 , further comprising:
a) transmitting, proximate to the first beam, a calibrator beam comprising a wide beam configured to span the angular range between the first angle and the second angle;
b) wherein the calibrator beam is transmitted with a constant phase value throughout the angular range between the first angle and the second angle.
7. The method of claim 6 , wherein the first beam and the calibrator beam occupy sequential symbol-times of a single subcarrier of a resource grid.
8. The method of claim 6 , wherein the first beam and the calibrator beam occupy sequential subcarriers of a single symbol-time of a resource grid.
9. The method of claim 1 , wherein the first and second wireless entities are mobile wireless devices, and the first beam is transmitted on a frequency allocated for sidelink communications.
10. The method of claim 1 , further comprising:
a) transmitting, by the first wireless entity, a second beam comprising a wide beam configured to span the angular range between the first angle and the second angle;
b) wherein the second beam comprises a second phase distribution which is modulated, at the first angle, according to the second phase value, and is modulated, at the second angle, according to the first phase value; and
c) wherein the second phase distribution varies monotonically, from the second phase value to the first phase value, as the angle ranges from the first angle to the second angle.
11. The method of claim 1 , further comprising:
a) before transmitting the first beam, transmitting or broadcasting a planning message that indicates the first and second phase values and the first and second angles.
12. The method of claim 1 , further comprising:
a) receiving a signal transmitted by the second wireless entity;
b) measuring a second received phase value of the signal, as received by the first wireless entity; and
c) transmitting a message to the second wireless entity, indicating the second received phase value.
13. The method of claim 12 , further comprising:
a) receiving, from the second wireless entity, a second reply message comprising an alignment direction toward the first wireless entity relative to the second wireless entity.