Lean deterministic beam/power feedback during 5G/6G initial access
For efficient communication in 5G and 6G, transmission beams are to be aligned with each user device as soon as possible during the initial access procedure. Prior-art procedures for downlink beam alignment consume large amounts of power and resources. Therefore, low-complexity formats and procedures are disclosed for a new user device to indicate its angular position relative to the base station upon entering the network. In one embodiment, the SSB message is broadcast isotropically, along with test signals which are transmitted in different directions. The user device indicates which test signal is best received, thereby indicating its angular direction. In a second embodiment, the test signals and feedback messages are appended to various entry messages after initial contact. Using either method, the base station and user device can then aim their beams toward the other, for enhanced signal quality thereafter.
1. A method for a base station of a wireless network to align a transmission beam toward a new user device during initial access, the method comprising:
a) transmitting a synchronization signal block (“SSB”) message and a plurality of test signals; and
b) receiving, from the new user device, a feedback message indicating which particular test signal was received with a highest signal quality;
c) wherein the synchronization signal block message, other than the test signals, is transmitted isotropically, wherein each test signal of the plurality is transmitted in a different direction, wherein the test signals are placed in a formerly unallocated portion of the synchronization signal block message, separate from a primary synchronization signal (“PSS”) and separate from a secondary synchronization signal (“SSS”) and separate from a physical broadcast channel (“PBCH”) message comprising the synchronization signal block message, and wherein the test signals are placed in a first symbol of a synchronization signal block message comprising four symbols, wherein the test signals are positioned to avoid overlapping a primary synchronization signal therein.
2. A method for a base station of a wireless network to align a transmission beam toward a new user device during initial access, the method comprising:
a) transmitting a synchronization signal block (“SSB”) message and a plurality of test signals; and
b) receiving, from the new user device, a feedback message indicating which particular test signal was received with a highest signal quality;
c) wherein the synchronization signal block message, other than the test signals, is transmitted isotropically, wherein each test signal of the plurality is transmitted in a different direction, wherein the test signals are placed in a formerly unallocated portion of the synchronization signal block message, separate from a primary synchronization signal (“PSS”) and separate from a secondary synchronization signal (“SSS”) and separate from a physical broadcast channel (“PBCH”) message comprising the synchronization signal block message, and wherein an indication of a latitude and a longitude of the base station is placed in the first symbol, not overlapping the primary synchronization signal and the test signals therein.
3. A method for a base station of a wireless network to align a transmission beam toward a new user device during initial access, the method comprising:
a) transmitting a synchronization signal block (“SSB”) message and a plurality of test signals; and
b) receiving, from the new user device, a feedback message indicating which particular test signal was received with a highest signal quality;
c) wherein the synchronization signal block message, other than the test signals, is transmitted isotropically, wherein each test signal of the plurality is transmitted in a different direction, wherein the test signals are placed in a formerly unallocated portion of the synchronization signal block message, separate from a primary synchronization signal (“PSS”) and separate from a secondary synchronization signal (“SSS”) and separate from a physical broadcast channel (“PBCH”) message comprising the synchronization signal block message, and wherein the test signals are placed in a last symbol of a synchronization signal block message comprising five or six symbols.