Signal Transmission with Broadened Beams for NTN Initial Access
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Solution Overview
Problem
The initial access delay of terminal devices in non-terrestrial networks is prolonged due to the long duration required for beam sweeping by satellites with large quantities of beams, leading to inefficient signal transmission.
Innovation Solution
A method involving a network device that broadens selected beams to reduce the number of beams required for signal transmission, optimizing beam width and gain distribution to minimize time domain resources and enhance signal-to-noise ratio, thereby reducing the duration and delay of initial access.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the satellite uses a large quantity of narrow beams to cover ultra-large ground area, then the coverage area is improved, but the beam sweeping duration and initial access delay increase significantly
Solution Approach 1:
The patent segments the large ground coverage area into multiple smaller coverage regions, each served by a broader beam. Instead of using many narrow beams to cover the entire area, the system divides the coverage area and assigns broader beams to each segment, reducing the total number of beams required and thus reducing beam sweeping duration.
Solution Approach 2:
The patent transitions from a one-dimensional approach (increasing beam quantity) to a two-dimensional approach (adjusting beam width and coverage area). By varying the beam width parameter, the system can cover the same ground area with fewer beams, effectively using beam width as an additional dimension to solve the coverage vs. time contradiction.
2Power
If the satellite increases the number of antennas to provide high array gain, then the transmit and receive array gain is improved, but the beam width decreases requiring more beams for coverage
Solution Approach 1:
The patent applies dynamic beam width adjustment, allowing the beam width to vary adaptively. Instead of using fixed narrow beams with high antenna gain, the system dynamically adjusts beam width to be broader when coverage is needed, and can use multiple narrower beams only when high precision is required. This dynamic adjustment resolves the contradiction between array gain and coverage efficiency.
Solution Approach 2:
The patent changes the beam width parameter from fixed narrow to variable broader widths. By adjusting this key parameter, the system achieves the same coverage area with fewer beams, thereby improving productivity while maintaining adequate array gain through optimized antenna resource allocation.
3Reliability
If the satellite performs beam sweeping on many beams with fixed periodicity, then the signal transmission reliability is improved, but the initial access delay increases
Solution Approach 1:
The patent applies partial action by performing beam sweeping on a reduced set of broader beams rather than all possible narrow beams. This partial approach maintains sufficient signal transmission reliability for initial access while significantly reducing the time required, as the broader beams provide adequate coverage with fewer instances.
Data Source
AI summary
A signal transmission method includes determining, a network device, M first beams from L first beams with different central directions, separately broadening the M first beams thereby obtaining M second beams, and separately performing signal transmission with the terminal device by using the M second beams. The M second beams are in a one-to-one correspondence with the M first beams. L is an integer greater than 1, and M is an integer less than L and greater than 1. A maximum gain of each of the M second beams is less than a maximum gain of a first beam corresponding to the second beam. The maximum gain of each of the M second beams is greater than or equal to a first value.