PBCH Beam Hopping Patterns for Energy-Efficient NR Broadcast
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Solution Overview
Problem
Current PBCH transmission methods in beamforming systems face challenges such as high beam sweep overhead, energy inefficiency, and reduced performance, particularly in 5G New Radio (NR) systems.
Innovation Solution
The proposed solution involves using beam hopping transmission schemes for PBCH, where the transmission is based on predefined beam hopping patterns or WTRU beam-location profiles, and incorporating inverse HARQ processes to enhance energy efficiency and reduce latency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If traditional beam sweep methods are used for PBCH transmission, then coverage is ensured, but beam sweep overhead increases and energy efficiency decreases
Solution Approach 1:
The patent implements beam hopping transmission where the PBCH is transmitted in a periodic manner across different beams according to a predefined hopping pattern. Instead of performing a complete beam sweep for every PBCH transmission, the system periodically hops between a subset of beams, reducing the time and energy overhead while maintaining coverage through the periodic nature of the transmission
Solution Approach 2:
The patent uses WTRU beam-location profiles that are determined in advance through uplink signal analysis. By pre-identifying the likely beam directions where WTRUs are located, the system can prioritize PBCH transmission in these specific beams, avoiding unnecessary transmissions in directions without WTRUs and thus reducing overhead and energy consumption
2Use of energy by stationary object
If beam hopping transmission is used for PBCH, then energy efficiency improves, but system information transmission reliability may be affected
Solution Approach 1:
The patent incorporates feedback mechanisms where WTRUs report their beam location information to the base station through uplink signals. The base station uses this feedback to refine the beam hopping pattern and prioritize transmissions in directions where WTRUs are actually located, ensuring reliable system information delivery while maintaining energy efficiency
Solution Approach 2:
The patent employs dynamic beam hopping patterns that can adapt to changing channel conditions and WTRU mobility. The beam hopping sequence is designed to cover different spatial directions over time, and the pattern can be adjusted based on observed WTRU locations and channel quality, ensuring that system information is reliably transmitted to moving WTRUs while maintaining energy efficiency
3Loss of time
If inverse HARQ processes are implemented, then latency is reduced and energy efficiency improves, but system complexity increases
Solution Approach 1:
The patent implements inverse HARQ processes where the traditional HARQ acknowledgment flow is inverted. Instead of the base station waiting for WTRU acknowledgments before retransmitting, the WTRU is configured to automatically receive and process PBCH transmissions in predetermined time windows without requiring explicit acknowledgment exchanges. This inversion eliminates the back-and-forth signaling overhead, reducing latency and energy consumption while the standardized inverse HARQ mechanism keeps the added complexity manageable
Data Source
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AI summary
A method for transmitting system information on a PBCH is described herein. A transmission/reception point (TRP) may generate a concatenated master information block (MIB) transport block that includes information bits associated with system bandwidth information, timing information, system frame number (SFN), a beam sweeping configuration, and a control resource set (CORESET). The TRP may then attach at least 16 cyclic redundancy check (CRC) bits to the concatenated MIB and then prioritize the concatenated MIB and the at least 16 CRC bits based on content. The TRP may then perform channel coding of the prioritized concatenated MIB and the at least 16 CRC bits to produce coded bits using at least one polar encoder with a coding rate that is less than 1/3, perform rate matching via repetition on the coded bits, and then transmit the rate matched, coded bits on the PBCH of a radio frame.